Clinical Evidence

Examining the Relationship Between Wound Complications and the Use of Resorbable Plates in Cranial Vault Reconstruction, Reilly et al. (2021).
J Craniofac Surg. 2021 Oct 1;32(7):2310-2313.
https://doi.org/10.1097/scs.0000000000007663

Abstract
Background: Resorbable plates are commonly used in cranial vault reconstruction surgery. There are few published papers examining their safety profile. The authors examined the prevalence of wound complications associated with the use of resorbable plates (Inion CPS Fixation System) in pediatric patients undergoing cranial vault reconstruction.

Methods: A retrospective review of patients (n = 182) who underwent cranial vault reconstruction using resorbable plate fixation was undertaken. All procedures were performed by a single Craniofacial Surgeon at the National Pediatric Craniofacial Center from 2008 to 2016. Wound complications were identified from a prospectively maintained database and medical note review. Several key patient characteristics and surgical variables were also recorded and tested for associations with wound complications.

Results: A total of 58.8% (107 of 182) of patients were male with a median age at surgery of 16.2 months. Overall, 12.1% (22 of 182) experienced a postoperative wound complication requiring hospital admission. A total of 2.73% (5 of 182) of the patients that returned to theatre had remnants of plates removed. The authors had a mean time from primary operation to secondary reoperation of 103 days. In univariate statistical analysis, females were more likely to develop a wound complication. However, in stratified analyses excluding patients with an underlying genetic syndrome, increasing age, and lower weight but not gender were associated with wound complications.

Conclusions: A 12.1% (22 of 182) wound complication rate with the use of the Inion CPS Fixation System was observed. Inion plates appear to have an equivalent safety profile to other fixation devices. Increasing age and lower weight were associated with an increased risk of wound complications in nonsyndromic patients.

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Delayed Foreign Body Reaction Caused by Bioabsorbable Plates Used for Maxillofacial Fractures, Jeon et al. (2016).
Arch Plast Surg. 2016 Jan;43(1):40-5.
https://doi.org/10.5999/aps.2016.43.1.40

Abstract
Background: Bioabsorbable plates and screws are commonly used to reduce maxillofacial bones, particularly in pediatric patients because they degrade completely without complications after bone healing. In this study, we encountered eight cases of a delayed foreign body reaction after surgical fixation with bioabsorbable plates and screws.

Methods: A total of 234 patients with a maxillofacial fracture underwent surgical treatment from March 2006 to October 2013, in which rigid fixation was achieved with the Inion CPS (Inion, Tampere, Finland) plating system in 173 patients and Rapidsorb (Synthes, West Chester, PA, USA) in 61 patients. Their mean age was 35.2 years (range, 15-84 years). Most patients were stabilized with two- or three-point fixation at the frontozygomatic suture, infraorbital rim, and anterior wall of the maxilla.

Results: Complications occurred in eight (3.4%) of 234 patients, including palpable, fixed masses in six patients and focal swelling in two patients. The period from surgical fixation to the onset of symptoms was 9-23 months. Six patients with a mass underwent secondary surgery for mass removal. The masses contained fibrous tissue with a yellow, grainy, cloudy fluid and remnants of an incompletely degraded bioabsorbable plate and screws. Their histological findings demonstrated a foreign body reaction.

Conclusions: Inadequate degradation of bioabsorbable plates caused a delayed inflammatory foreign body reaction requiring secondary surgery. Therefore, it is prudent to consider the possibility of delayed complications when using bioabsorbable plates and surgeons must conduct longer and closer follow-up observations.

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Use of biodegradable plates and screws in the treatment of pediatric facial bone fractures, Ali et al. (2016).
Egyptian Journal of Oral & Maxillofacial Surgery 7.3 (2016): 86-93.
https://doi.org/10.1097/01.OMX.0000496444.08336.3d

Abstract
Background
Pediatric patients with facial fractures are a unique challenge in terms of their treatment planning, which is different from that of adult patients. Early literature has advocated conservative closed management of pediatric facial fractures to prevent complications. However, recent advances in treatment have enabled us to use biodegradable plates and screws, which overcome the limitations of metallic plates.

Aim
This study was conducted to evaluate the effectiveness of Inion CPS biodegradable plates and screws on pediatric facial fractures.

Patients and methods
The study was conducted on 30 pediatric patients with maxillofacial fractures requiring open reduction and internal fixation. Fractures with infection and comminuted fractures were excluded. Patients were aged 3–12 years, 18 boys and 12 girls, with different types of trauma: 12 patients had suffered falls, 12 patients had middle cerebral artery (MCA), four patients had sports-related fracture; and two patients had assault-related fractures. The site of fracture was different: 18 patients had mandibular fractures, four patients had zygomatic complex fractures, four patients had orbital fractures, two patients had maxillary fractures (one isolated and the other with mandibular fracture), and one patient had frontal bone and sinus fractures (anterior wall). Fractures were plated with a biodegradable system (Inion CPS) using standard plating principles. Postoperative complications were assessed.

Results
Satisfactory reduction was obtained in all patients, as judged from the position of the fracture segments in 24-h postoperative radiographs compared with all subsequently obtained images. The undisturbed reduction was considered as a marker of the stable fixation provided by the bioresorbable system. The screw holes visible as radiolucencies on the radiograph were also seen to maintain their position throughout the period of follow-up.

Conclusion
In our study, we concluded that the use of Inion bioresorbable plates is effective in the treatment of facial fracture in pediatric patients. There was no complication and no growth disturbance in the follow-up period, which proves that bioresorbable plates provide stable fixation in children. Our data support the use of bioresorbable plate fixation in pediatric craniofacial surgery as a means of avoiding the potential and well-documented problems associated with rigid metal fixation.

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Management of pediatric mandibular fractures using bioresorbable plating system – Efficacy, stability, and clinical outcomes: Our experiences and literature review, Singh et al. (2016).
J Oral Biol Craniofac Res. 2016 May-Aug;6(2):101-6.
https://doi.org/10.1016/j.jobcr.2015.09.004

Abstract
Aims: The purpose of this study was to determine the efficacy and stability of the biodegradable fixation system for treatment of mandible fractures in pediatric patients by measuring the bite force.

Methods: Sixty pediatric patients with mandibular fractures (36 males, 24 females) were included in this study. The 2.5-mm resorbable plates were adapted along Champy’s line of ideal osteosynthesis and secured with four 2.5 mm diameter monocortical resorbable screws, 8 mm in length. All patients were followed for 10 months. Clinical parameters, such as soft tissue infection, nonunion, malunion, implant exposure, malocclusion, nerve injury, and bite force for stability, were prospectively assessed.

Results: Adequate fixation and primary bone healing was achieved in 100% of the cases. Six minor complications (10%) were observed: 2 soft tissue infections (3%), 1 plate dehiscence (2%), 1 malocclusion (2%), and 2 paresthesia (3%).

Conclusion: 2.5-mm resorbable plating system along Champy’s line of ideal osteosynthesis is a good treatment modality for mandible fractures in pediatric patients.

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Clinical and radiographic evaluation of biodegradable bone plates in the treatment of mandibular body fractures, Elhalawany et al. (2015).
Niger Med J. 2015 Jan-Feb;56(1):48-53.
https://doi.org/10.4103/0300-1652.149171

Abstract
Background: Many different systems are available for the treatment of fractures ranging from the heavy compression plates for mandibular reconstruction to low profile plates for mid-facial fixation, and are made either from stainless steel, titanium or vitallium. Recently, biodegradable, self-reinforced polylactide plates and screws have been used for the internal fixation of fractures of the mandible with good results.

Aim of this study: This study evaluated clinically the biodegradable bone plates for treatment of mandibular body fracture and to evaluate bone healing during the follow-up period using digital radiography.

Materials and methods: Eight patients had been suffered from mandibular body fractures were treated using Inion CPS(TM) bioresorbable fixation system and the healing process were followed up using digitised panoramic radiography at first week and after 1, 3 and 6 months.

Results: Clinical examination of fractured segments revealed stable fixation across the fracture sites while visual and quantitative assessment of radiograph showed healing process was comparable with results previously reported by titanium bone plates.

Conclusion: Open reduction and internal fixation of mandibular fractures using bioresorbable fixation system with a brief period of inter-maxillary fixation have evolved to the point where the physical properties are sufficient to withstand the post-operative loads required for fracture repair of mandibular body fractures. The foreign body reaction is a major material-related problem which requires further studies.

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Comparison of the long-term skeletal stability between a biodegradable and a titanium fixation system following BSSO advancement – a cohort study based on a multicenter randomised controlled trial, Van Bakelen et al. (2015).
Br J Oral Maxillofac Surg. 2014 Oct;52(8):721-8.
https://doi.org/10.1016/j.bjoms.2014.06.014

Abstract
Biodegradable fixation systems could reduce or eliminate the problems associated with removal of titanium plates. A multicenter randomised controlled trial (RCT) was performed in the Netherlands from December 2006-July 2009, and originally 230 injured and orthognathic patients were included. The patients were randomly assigned to either a titanium control group (KLS Martin) or to a biodegradable test group (Inion CPS). The aim of the present study was to compare the long-term skeletal stability of advancement bilateral sagittal split osteotomies (BSSO) of a biodegradable system and a titanium system. Only patients from the original RCT who were at least 18 years old and who had a BSSO advancement osteotomy were included. Those who had simultaneous Le Fort I osteotomy or genioplasty were excluded. Analysis of skeletal stability was made by digital tracing of lateral cephalograms. Long-term skeletal stability in BSSO advancement did not differ significantly between patients treated with biodegradable plates and screws and those treated with titanium plates and screws. Given the comparable amount of relapse, the general use of Inion CPS in the treatment of BSSO advancement should not be discouraged. On the basis of other properties a total picture of the clinical use can be obtained; the short-term stability, the intraoperative switches, the number of plates removed and cost-effectiveness. Trial registration of original RCT: http://www.controlled-trials.com; ISRCTN 44212338.

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Comparison of resorbable plates and titanium plates for fixation stability of combined mandibular symphysis and angle fractures, Lim et al. (2014).
J Korean Assoc Oral Maxillofac Surg. 2014 Dec;40(6):285-90.
https://doi.org/10.5125/jkaoms.2014.40.6.285

Abstract
Objectives: We compared resorbable plates with titanium plates for treatment of combined mandibular angle and symphyseal fractures.

Materials and methods: Patients with mandibular angle and symphysis fractures were divided into two groups. The control (T) group received titanium plates while the experimental (R) group received resorbable plates. All procedures were carried out under general anesthesia using standard surgical techniques. We compared the frequency of wound dehiscence, development of infection, malocclusion, malunion, screw breakage, and any other technical difficulties between the two groups.

Results: Thirteen patients were included in the R group, where 39 resorbable plates were applied. The T group consisted of 16 patients who received 48 titanium plates. The mean age in the R and T groups was 28.29 and 24.23 years, respectively. Primary healing of the fractured mandible was obtained in all patients in both groups. Postoperative complications were minor and transient. Moreover, there were no significant differences in the rates of various complications between the two groups. Breakage of 3 screws during the perioperative period was seen in the R group, while no screws or plates were broken in the T group.

Conclusion: Resorbable plates can be used to stabilize combined mandibular angle and symphysis fractures.

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Can resorbable screws effectively be used in fixating bilateral sagittal split osteotomies for mandibular advancement? A randomized controlled trial, Yu et al. (2014).
J Oral Maxillofac Surg. 2014 Nov;72(11):2273-7.
https://doi.org/10.1016/j.joms.2014.04.033

Abstract
Purpose: Resorbable fixation material is an attractive option for those patients undergoing orthognathic surgery. The efficacy of resorbable screws was tested in bilateral mandibular sagittal split osteotomies (BSSOs) performed for correction of retrognathic mandibles.

Materials and methods: One hundred one patients were enrolled in this prospective randomized clinical trial. Patients in group 1 (n = 51) received titanium screws (Stryker) and patients in group 2 (n = 50) received resorbable screws (Inion CPS). Outcome measurements were compared for statistical significance.

Results: There was a statistically significant difference in the use of postoperative elastics (P < .0001). There was no statistically significant difference in other outcome measurements, including clinical evidence of relapse.

Conclusion: Resorbable screws can be used effectively for fixation of BSSO for mandibular advancement. A higher incidence of rotation around positional screws can result secondary to the mechanical “looseness” when using resorbable screws. This can be treated effectively using Class III mechanic elastics during the initial stages of bone healing.

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3D vector analysis of mandibular condyle stability in mandibular setback surgery with bicortical bioabsorbable screw fixation, Lee et al. (2014).
J Craniomaxillofac Surg. 2014 Jul;42(5):e105-10.
https://doi.org/10.1016/j.jcms.2013.07.005

Abstract
Introduction: Bioabsorbable screws became widely used for stable fixation in orthognathic surgery as biomechanical technology advanced. Recently, 3D image analyses begin to be used to evaluate surgical changes. The purpose of this study was to evaluate, using 3D vector analysis, the stability of bicortical bioabsorbable screw fixation in mandibular setback using a sagittal split ramus osteotomy. Spatial change of the mandibular condyle was determined by 3D coordinates containing directional information.

Materials and methods: Bicortical screw fixation was performed using either a bioabsorbable screw (25 patients) or a titanium screw (5 patients) in orthognathic surgery. Pre- and post-operative CT images (6 months after surgery) were superimposed digitally. A 3D coordinate (X, Y, Z) and vectors were employed to quantify spatial changes of the condyle and analysed statistically.

Results: Measuring on 3D image showed stable error about 0.16 mm. There were no significant differences in the total spatial changes of the condyle between titanium and bioabsorbable screws with the exception of the lateral-medial direction of the condylar centre (P = 0.042). The directional vector components were stable, regardless of mandibular setback.

Conclusion: In 3D vector analysis, bioabsorbable screw fixation in SSRO with distal segment osteotomy shows clinically acceptable postoperative condylar position stability.

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Skeletal stability of bioresorbable fixation in orthognathic surgery: a systemic review, Yang et al. (2014).
J Craniomaxillofac Surg. 2014 Jul;42(5):e176-81.
https://doi.org/10.1016/j.jcms.2013.08.003

Abstract
Background: Over the past 20 years, there has been an increase in the use of bioresorbable fixation system in orthognathic surgery, but concerns remain about the stability of fixation. This review is to seek evidence for the effectiveness of bioresorbable fixation systems compared to titanium systems used for orthognathic surgery.

Methods: A systematic review of the scientific literature listed on PubMed, Embase, Cochrane Central Register of Systemic Reviews and Cochrane Central Register of Controlled Trials was performed, up to December 2012.

Results: Twenty articles were selected based on inclusion and exclusion criteria: five RCTs and fifteen prospective. We compared these studies, published between 1997 and 2012 and involving 1092 participants examining skeletal stability of bioresorbable fixation in orthognathic surgery.

Conclusion: This review found that the published data have shown that bioresorbable fixation systems produce reliable skeletal stability.

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The “in situ molding technique: ” an accurate and simple way to fix resorbable plates to the facial skeleton, Sadigh et al. (2014).
J Craniofac Surg. 2014 Sep;25(5):1766-8.
https://doi.org/10.1097/scs.0000000000000884

Abstract
Bioabsorbable plates developed for use in the facial skeleton have become an integral part of the craniomaxillofacial surgeon’s reconstructive armamentarium. They avoid the problems associated with the retention of metal plates and can be easily contoured when heated in a thermobath. The technical process of molding and securing these devices, often through small access incisions, to achieve rigid fixation of facial fractures can be difficult. In this article, we describe a simple, novel technique that we have developed, using hot water suction irrigation, to achieve in situ molding of resorbable plates during facial fracture fixation. We used this technique to fix 123 facial fractures in 110 patients over a 4-year period. No complications secondary to the use of hot water suction irrigation were encountered.

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Are bioresorbable polylactate devices comparable to titanium devices for stabilizing Le Fort I advancement?, Blakey et al. (2014).
Int J Oral Maxillofac Surg. 2014 Apr;43(4):437-44.
https://doi.org/10.1016/j.ijom.2013.10.006

Abstract
The purpose of this study was to evaluate whether skeletal and dental outcomes following Le Fort I surgery differed when stabilization was performed with polylactate bioresorbable devices or titanium devices. Fifty-seven patients with preoperative records and at least 1 year postoperative records were identified and grouped according to the stabilization method. All cephalometric X-rays were traced and digitized by a single operator. Analysis of covariance was used to compare the postsurgical change between the two stabilization methods. Twenty-seven patients received bioresorbable devices (group R), while 30 received titanium devices (group M). There were no statistically significant differences between the two groups with respect to gender, race/ethnicity, age, or dental and skeletal movements during surgery. Subtle postsurgical differences were noted, but were not statistically significant. Stabilization of Le Fort I advancement with polylactate bioresorbable and titanium devices produced similar clinical outcomes at 1 year following surgery.

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To evaluate the efficacy of biodegradable plating system for fixation of maxillofacial fractures: A prospective study, Bali et al. (2013).
Natl J Maxillofac Surg. 2013 Jul;4(2):167-72.
https://doi.org/10.4103/0975-5950.127645

Abstract
Aims: The present study was undertaken to evaluate the efficacy of biodegradable plating system for fixation of maxillofacial fractures and to study the morbidity associated with the use of biodegradable plates and screws.

Materials and methods: This prospective study consisted of 10 patients with maxillofacial fractures requiring open reduction and internal fixation. Fractures with infection, comminuted and pathological fractures were excluded. All were plated with biodegradable system (Inion CPS) using standard plating principles and observed for a total period of 24 weeks. Characteristics of the fractures, ease of use of bioresorbable plate/screw system and post operative complications were assessed.

Results: Of total 10 patients, eight patients were of midface fracture and two pediatric patients with mandibular fracture, with nine male and one female. The mean age was 32.8 years. Out of 20 plates and 68 screws applied to the 10 fractures sites; there were three incidences of screw breakage with no other intraoperative difficulties. Paresthesia of the infraorbital nerve was present in two patients, and recovered completely in four weeks after surgery. Fracture reduction was considered to be satisfactory in all cases. One patient developed postsurgical infection and was managed with oral antibiotics and analgesics.

Conclusions: Favorable healing can be observed through the use of biodegradable plates and screws to stabilize selected midface fractures in patients of all ages, as well as mandible fractures in early childhood, however further studies with more sample size are required.

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Treatment of mandible fractures using resorbable plates with a mean of 3 weeks maxillomandibular fixation: a prospective study, Vázquez-Morales et al. (2013).
Oral Surg Oral Med Oral Pathol Oral Radiol. 2013 Jan;115(1):25-8.
https://doi.org/10.1016/j.oooo.2012.03.019

Abstract
Purpose: In this study, a 2.5-mm resorbable plating system (Inion CPS, Tampere Finland) was assessed for the fixation of mandibular fractures with 3 weeks of maxillomandibular fixation.

Patients and methods: Fifty mandibular fractures in 34 patients (32 males, 2 females) with a mean of 20.8 days of maxillomandibular fixation (MMF) were included in this study. The 2.5-mm resorbable plates were adapted along Champy’s line of ideal osteosynthesis and secured with four 8 × 2.5 mm monocortical resorbable screws. All patients were followed for a minimum of 6 weeks with an average long-term follow-up of 10 months. The incidence of soft tissue infection, nonunion, malunion, malocclusion, osteomyelitis, nerve injury, and tooth damage was prospectively assessed.

Results: Primary bone healing was achieved in 100% of cases. Ten minor complications (20%) were observed: 5 soft tissue infections (10%), 4 plate dehiscences (8%), and 1 malocclusion (2%). No evidence of malunion, nonunion, osteomyelitis, plate fracture, or iatrogenic dental or nerve injury was noted; no readmission or reoperation was necessary.

Conclusion: The Inion 2.5-mm resorbable plating system along Champy’s line of ideal osteosynthesis plus 3 weeks of MMF is a viable option for the treatment of mandible fractures.

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Can resorbable screws effectively be used in fixating bilateral sagittal split osteotomies for mandibular advancement? A randomized controlled trial, Yu and Bloomquist (2013).
J Oral Maxillofac Surg. 2014 Nov;72(11):2273-7.
https://doi.org/10.1016/j.joms.2014.04.033

Abstract
Purpose: Resorbable fixation material is an attractive option for those patients undergoing orthognathic surgery. The efficacy of resorbable screws was tested in bilateral mandibular sagittal split osteotomies (BSSOs) performed for correction of retrognathic mandibles.

Materials and methods: One hundred one patients were enrolled in this prospective randomized clinical trial. Patients in group 1 (n = 51) received titanium screws (Stryker) and patients in group 2 (n = 50) received resorbable screws (Inion CPS). Outcome measurements were compared for statistical significance.

Results: There was a statistically significant difference in the use of postoperative elastics (P < .0001). There was no statistically significant difference in other outcome measurements, including clinical evidence of relapse.

Conclusion: Resorbable screws can be used effectively for fixation of BSSO for mandibular advancement. A higher incidence of rotation around positional screws can result secondary to the mechanical “looseness” when using resorbable screws. This can be treated effectively using Class III mechanic elastics during the initial stages of bone healing.

Link to the article

Two-Year Follow-up on the Use of Absorbable Mesh Plates in the Treatment of Medial Orbital Wall Fractures, You et al. (2013).
Arch Plast Surg. 2013 Nov;40(6):728-34.
https://doi.org/10.5999/aps.2013.40.6.728

Abstract
Background: Absorbable materials offer many advantages in the reconstruction of orbital walls; however, the possibility of postoperative enophthalmos after complete absorption cannot be excluded. We evaluated the postoperative results of absorbable mesh plates used as onlay implanting on the medial orbital wall to determine whether they are suitable for medial orbital wall reconstruction.

Methods: The study included 20 patients with medial orbital wall fractures who were followed up for more than 2 years postoperatively. We used absorbable mesh plates in all of the patients. We measured the following: the changes in the expanded orbital volume by comparing the preoperative and postoperative computed tomography (CT) scans and the degree of clinical enophthalmos.

Results: There were no major complications associated with the use of absorbable materials such as infection, migration, or extrusion of mesh plates during the long-term follow-up. The orbital volumetric changes between the preoperative and postoperative CT scans were not statistically significant. However, the expanded orbital volume was not related to the degree of clinical enophthalmos.

Conclusions: The reconstructed orbital wall may provide supportive scar tissue to the orbital contents even after the absorbable materials have dissolved completely. Absorbable mesh plates could be another option for the reconstruction of the medial orbital wall.

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Evaluation of the Fatigue Performance and Degradability of Resorbable PLDLLA-TMC Osteofixations, Landes et al. (2013).
Open Biomed Eng J. 2013 Nov 29;7:133-46.
https://doi.org/10.2174/1874120701307010133

Abstract
The fatigue performance of explanted in-situ degraded osteofixations/osteosyntheses, fabricated from poly (70L-lactide-co-24DL-lactide-6-trimethylane-carbonate or PLDLLA-TMC) copolymer was compared to that of virgin products. The fatigue test was performed on 21 explants retrieved from 12 women and 6 men; 16-46 years by a custom-designed three-point bend apparatus using a staircase method and a specified failure criterion (an increase of the deflection of the specimen > 1 mm) with run-out designated as “no failure” after 150,000 loading cycles. While all the virgin products showed run-out at 38N, all of the specimens fabricated from explants failed at this load level. For the explant specimens, although there was a trend of decreased failure load with increased in-situ time, this decrease was pronounced after 4 months in-situ, however, not yet statistically significant, while a 6-month in-situ explant had significantly less failure load. Three and four month in-situ explants had highly significant differences in failure load between measurements close and distant to the osteotomy line: p=0.0017 (the region of maximum load in-situ). In the virgin products, there were only traces of melt joining and cooling, left from a stage in the manufacturing process. For the implants retrieved after 4.5 months in-situ, the fracture surfaces showed signs of degradation of the implants, possibly caused by hydrolysis, and for those retrieved after 9 months in-situ, there were cracks and pores. Thus, the morphological results are consistent with those obtained in the fatigue test. The present results suggest that resorbable osteofixations fabricated from PLDLLA-TMC are stable enough to allow loading of the healing bone and degrade reliably.

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Fixation of zygomatic and mandibular fractures with biodegradable plates, Degala et al. (2013).
Ann Maxillofac Surg. 2013 Jan;3(1):25-30.
https://doi.org/10.4103/2231-0746.110072

Abstract
Context: In this prospective study, 13 randomly selected patients underwent treatment for zygomatic-complex fractures (2 site fractures) and mandibular fractures using 1.5 / 2 / 2.5-mm INION CPS biodegradable plates and screws.

Aims: To assess the fixation of zygomatic-complex and mandibular fractures with biodegradable copolymer osteosynthesis system.

Materials and methods: In randomly selected 13 patients, zygomatic-complex and mandibular fractures were plated using resorbable plates and screws using Champy’s principle. All the cases were evaluated clinically and radiologically for the type of fracture, need for the intermaxillary fixation (IMF) and its duration, duration of surgery, fixation at operation, state of reduction at operation, state of bone union after operation, anatomic reduction, paresthesia, occlusal discrepancies, soft tissue infection, immediate and late inflammatory reactions related to biodegradation process, and any need for the removal of the plates.

Statistical analysis used: Descriptives, Frequencies, and Chi-square test were used.

Results: In our study, the age group range was 5 to 55 years. Road traffic accidents accounted for the majority of patients six, (46.2%). Postoperative occlusal discrepancies were found in seven patients as mild to moderate, which resolved with IMF for 1-8 weeks. There were minimal complications seen and only as soft tissue infection.

Conclusions: Use of biodegradable osteosynthesis system is a reliable alternative method for the fixation of zygomatic-complex and mandibular fractures. The biodegradable system still needs to be refined in material quality and handling to match the stability achieved with metal system. Biodegradable plates and screws is an ideal system for pediatric fractures with favorable outcome.

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Bio-resorbable plates as effective implant in paediatric mandibular fracture, Singh et al. (2012).
J Maxillofac Oral Surg. 2012 Dec;11(4):400-6.
https://doi.org/10.1007/s12663-011-0330-x

Abstract
Aim: To evaluate the efficacy of bio-resorbable plates in paediatric mandibular fracture.

Materials and methods: In the present study, 40 cases of mandibular fractures were treated by Inion Cps plating system using, 2 and 2.5 mm (LPLA/DLPLA/TMC/PGA) bio-resorbable bone plates and screws of 6 and 8 mm screws. The assessment of the patients was done at 2 week, 1, 3, and 6 months using the clinical parameters and bite force recording.

Results: There was significant reduction in pain at different follow-ups. Paraesthesia was found in two patients with body fracture which remained for 2 week and 1 month follow-up. No paraesthesia was found after 3rd follow-up. Significant stability of fracture fragments were found on different follow ups. Implant exposure was present only in two patients (5%) at 1 month follow up. There was significant increase in incisor, right molar and left molar bite force at 1, 3 and 6 months, from 2nd week onwards.

Conclusion: These findings show that the use of bio-resorbable plates in paediatric mandibular fracture was efficacious enough to bear the masticatory loads during osteosynthesis of the fracture. The recent and significant achievement is the advent of bio-resorbable osteosynthesis devices that has almost solved the problems of stress shielding, secondary surgery and corrosion when metal implants are left-in situ.

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Comparative study of skeletal stability between bicortical resorbable and titanium screw fixation after sagittal split ramus osteotomy for mandibular prognathism, Paeng et al. (2012).
J Craniomaxillofac Surg. 2012 Dec;40(8):660-4.
https://doi.org/10.1016/j.jcms.2011.11.001

Abstract
Introduction: Resorbable screw fixation for orthognathic surgery is widely used in oral and maxillofacial surgery and has several advantages. However, surgeons are concerned about using resorbable screws in orthognathic surgery because of possible postoperative complications such as relapse, screw fracture, and infection. The purpose of this study was to evaluate the skeletal stability of bicortical resorbable screw fixation after sagittal split ramus osteotomies for mandibular prognathism.

Materials and methods: This study included 25 patients who underwent mandibular setback surgery fixed with resorbable screws after sagittal split osteotomy at the Department of Oral and Maxillofacial Surgery at Seoul National University Dental Hospital. Five resorbable screws (Inion CPS(®), Inion Ltd., Finland) were applied bicortically at each osteotomy site via a transbuccal approach. No rigid intermaxillary fixation was applied on the first postoperative day. Passive mouth opening exercises were allowed, using two light, rubber elastics for guidance. The control group was 25 patients fixed with four titanium screws. The follow-up period was 12-22 months (mean 17.8 months). Postoperative skeletal changes on lateral cephalometric radiographs were analyzed and compared between the two groups preoperatively, immediately postoperatively, and 6 months postoperatively.

Results: The average setback was 6.9 mm and no major intraoperative complications occurred. One patient experienced infection immediately after surgery that was controlled uneventfully. The data did not demonstrate any significant difference in postoperative skeletal stability between the two groups. Differences between the immediate postoperative state and 6 months after surgery were not significant. In earlier cases, especially for patients with severe mandibular prognathism, immediate postoperative elastic traction was needed for stable occlusal guidance.

Conclusions: The results of this study indicate that bicortical resorbable screws offer a clinically stable outcome for the fixation of mandibular sagittal split osteotomies in mandibular prognathism. However the resorbable screws showed less stable results vertically than the titanium screws.

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Treatment of frontal sinus fracture using bioabsorbable mesh plates, Kim et al. (2012).
J Craniofac Surg. 2012 Mar;23(2):549-51.
https://doi.org/10.1097/scs.0b013e3182418f40

Abstract
Accurate reduction and stable fixation are important in the treatment of frontal sinus fracture. Usually, metal plates and screws were used because of easy handling and delicate fixation. However, palpability and possibility for secondary operation for plate removal were shortcomings. For improving these problems, we used absorbable mesh plate for fixation of reduced frontal bones.In this study, 14 patients with frontal sinus fracture were treated by open reduction and rigid fixation using absorbable mesh plates. Mean follow-up period was 17.6 months. Considering anterior and posterior table involvement, nasofrontal duct injury, and concomitant neurosurgical problems, additional surgical procedures including degloving sinus mucosa, cranialization, and obliteration of nasofrontal duct were also conducted.There was no remarkable early and late postoperative complication. Aesthetic results were also satisfactory. Absorbable mesh plates were easy to mold and convenient for screw fixation. Moreover, there was no necessity of secondary operation for removal of plates.We believe that absorbable mesh plates might be a useful material for fixation instead of metal plates and screws especially in mild to moderate degree of frontal bone fractures.

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Effect of number and geometry of resorbable screws on biomechanical stability of in vitro model with sagittal split ramus osteotomy, Hwang et al. (2012).
J Craniofac Surg. 2012 Mar;23(2):363-6.
https://doi.org/10.1097/scs.0b013e318240c826

Abstract
The purpose of this study was to investigate the effect of the number and the geometry of resorbable screws (RSs; Inion CPS System; Inion Ltd, Tampere, Finland) on the biomechanical stability of the in vitro model with sagittal split ramus osteotomy. The sagittal split ramus osteotomy polyurethane hemimandible (Synbone, Malans, Switzerland) was fixed by 7 osteosynthesis methods after 5 mm advancement of the distal segment (n = 5 for each method): 1TP (1 titanium miniplate and 4 screws), 3RL (3 RSs with linear configuration at the retromolar area [RMA]), 2R1B (2 RSs at RMA and 1 RS at the mandibular body [MB]), 2R1A (2 RSs at the RMA and 1 RS at the mandibular angle [MA]), 3R1B (3 RSs at RMA and 1 RS at the MB), 3R1A (3 RSs at RMA and 1 RS at the MA), and 3R1A1B (3 RSs at the RMA, 1 RS at the MA, and 1 RS at the MB). Values of linear compressive load were measured at 1- to 5-mm displacement of the lower first molar with a 1-mm interval and were statistically analyzed. From 1- to 5-mm displacement, there were significant differences in load values among groups (P < 0.05, P < 0.01, P < 0.01, P < 0.001, and P < 0.001, respectively). When the amount of displacement was increased, the difference in load values between 1TP, 3RL, and 2R1B became significantly prominent. There was a significant difference in total load values according to number and geometry of RSs (P < 0.001). All kinds of geometry with more than 3 RSs were more rigid than 1TP. The 3R1A1B method showed better biomechanical stability than 1TP, 3RL, and 2R1B. In 3 RS and 4 RS groups, fixation in MA (2R1A, 3R1A) exhibited a tendency of better stability than fixation in MB (2R1B, 3R1B). Fixation with 2R1A could provide better biomechanical stability than 1TP and similar rigidity with 3R1A1B.

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Comparative study of bone repair in mandibular body osteotomy between metallic and absorbable 2.0 mm internal fixation systems. Histological and histometric analysis in dogs: a pilot study, Sverzut et al. (2012).
Int J Oral Maxillofac Surg. 2012 Nov;41(11):1361-8.
https://doi.org/10.1016/j.ijom.2012.04.012

Abstract
The objective of this study was to compare the bone repair along a mandibular body osteotomy stabilized with 2.0 mm absorbable and metallic systems. 12 male, adult mongrel dogs were divided into two groups (metallic and absorbable) and subjected to unilateral osteotomy between the mandibular third and fourth premolars, which was stabilized by applying two 4-hole plates. At 2 and 18 weeks, three dogs from each group were killed and the osteotomy sites were removed and divided equally into three parts: the upper part was labelled the tension third (TT), the lower part the compression third (CT), and the part between the TT and CT the intermediary third (IT). Regardless of the treatment system, union between the fragments was observed at 18 weeks and the CT showed more advanced stages of bone repair than the TT. Histometric analysis did not reveal any significant differences among the 3 parts or systems in the distance between bone fragments at 2 weeks. Although at 18 weeks the proportions of newly formed bone did not differ among TT, IT and CT, significantly enhanced bone formation was observed in all sections for the metallic group. The patterns of repair were distinct between treatments.

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Segmental stability of resorbable P(L/DL)LA-TMC osteosynthesis versus titanium miniplates in orthognatic surgery, Ballon et al. (2012).
J Craniomaxillofac Surg. 2012 Dec;40(8):e408-14.
https://doi.org/10.1016/j.jcms.2012.02.014

Abstract
After two decades of the use of resorbable miniplates, new polymer compositions for resorbable osteosynthesis are still being developed to make the handling and outcome of operations even more predictable and give higher stability to the repositioned segments. This study investigates a new resorbable osteosynthesis system in orthognathic patients. 50 patients were treated with P(L/DL)LA-TMC resorbable osteosynthesis and compared to a group of 50 patients treated with titanium miniplates. Segmental stability and relapse were measured comparing preoperative, postoperative and follow-up lateral cephalograms. Throughout this study, resorbables appeared to be as stable as titanium miniplates except in maxillary elongation and mandibular setback. Here, the titanium miniplates showed significantly higher stability than resorbable plates. P(L/DL)LA-TMC osteosynthesis seem to have less strength against compressive forces after maxillary elongation and they are less resistant to the forces the tongue exerts, pressing against the mandible after setback. It can therefore be concluded that the resorbable osteosynthesis can be used in the same situations as titanium miniplates except in maxillary elongation and mandibular setback.

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Patients’ preoperative expectations and postoperative satisfaction of dysgnathic patients operated on with resorbable osteosyntheses, Ballon et al. (2011).
J Craniofac Surg. 2011 Mar;22(2):730-4.
https://doi.org/10.1097/scs.0b013e318207b700

Abstract
Background: This study evaluated whether personal expectations and satisfaction throughout orthognathic surgery were fulfilled. In addition, patients were interrogated about their experience of resorbable osteosynthesis.

Methods: A total of 50 patients were interviewed 3 times each throughout the study by a mixed questionnaire of standard psychologic tests and a tailored itemized questionnaire regarding their expectations regarding resorbable osteofixation and their postoperative satisfaction.

Results: A postoperative increase in self-esteem and approach to life were evident. An examination of Oral Health-Related Quality of Life showed constant quality of life; an examination of Oral Health Impact Profile-Germany) showed no postoperative difficulties in dental hygiene and nutrition. No statistically significant change in any of the tests could be expressly determined. Avoidance of secondary surgery motivated 94% to choose resorbable osteofixations, although a mere 66% had heard of them before; 90% of patients were satisfied with the operation result.

Conclusions: Orthognathic surgery cannot change preexistent depression or a problematic social background. Mastication and oral health improved, and postoperative happiness and confidence increased. When given the choice between resorbable fixation and titanium osteofixation, patients generally preferred resorbable fixations.

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Poster 49: Assessment of Biomechanical Stability, Stress Distribution and Resorption Patterns of Biodegradable 2.0mm Inion® CPS Fixation System in a Rabbit Model, Atali et al. (2011).
J Oral Maxillofac Surg 2011; 69(9).
https://doi.org/10.1016/j.joms.2011.06.149

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Poster 66: Evaluation of the Inion Resorbable Plating System for Open Reduction Internal Fixation (ORIF) of Mandible Fractures, Rock et al. (2011).
J Oral Maxillofac Surg 2011;69(9).
https://doi.org/10.1016/j.joms.2011.06.166

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The perilobule approach to subcondylar fractures, Baek et al. (2011).
Ann Plast Surg. 2011 Mar;66(3):253-6.
https://doi.org/10.1097/sap.0b013e3181e1333f

Abstract
Several approaches to the management of subcondylar fractures have been used, including the submandibular approach, the preauricular approach, and the retromandibular approach. Although they provide excellent access to repair fractures of body, ramus, and condyle, we have found it difficult to manage subcondylar fractures using either of these approaches. We describe a novel approach for subcondylar fractures that provides direct access to the fracture site. A total of 17 consecutive patients underwent open reduction and internal fixation of their subcondylar fractures using this technique. The incision line is located just anterior and posterior to the ear lobe, and is comprised of lower part preauricular and upper retroauricular incisions. Intraoperatively, the method applied shortened the time necessary for and simplified the procedure of reduction and osteosynthesis. The postoperative course was uneventful in most patients. Radiologic follow-up revealed correct reduction and fixation in all the cases. There were no occlusal disturbances, no trismus, no lateral deviations of the mandible, and no nerve lesions. Our findings indicate that the short perilobe approach is an easy and safe technique for displaced subcondylar fractures.

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Biodegradable fixation for craniomaxillofacial surgery: a 10-year experience involving 761 operations and 745 patients, Turvey et al. (2011).
Int J Oral Maxillofac Surg. 2011 Mar;40(3):244-9.
https://doi.org/10.1016/j.ijom.2010.11.024

Abstract
Patient acceptance, safety, and efficacy of poly-l/dl-lactic acid (PLLDL) bone plates and screws in craniomaxillofacial surgery are reported in this article. Included in the sample are 745 patients who underwent 761 separate operations, including more than 1400 surgical procedures (orthognathic surgery (685), bone graft reconstruction (37), trauma (191) and transcranial surgery (20)). The success (no breakage or inflammation requiring additional operating room treatment) was 94%. Failure occurred because of breakage (14) or exuberant inflammation (31). All breakage occurred at mandibular sites and the majority of inflammatory failure occurred in the maxilla or orbit (29), with only two in the mandible. Failures were evenly distributed between the two major vendors. PLLDL 70/30 bone plates and screws may be used successfully in a variety of craniomaxillofacial surgical applications. The advantages include the gradual transference of physiological forces to the healing bone, the reduced need for a second operation to remove the material and its potential to serve as a vehicle to deliver bone-healing proteins to fracture/osteotomy sites. Bone healing was noted at all sites, even where exuberant inflammation required a second surgical intervention.

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Evaluating the applicability of a biodegradable osteosynthesis plating system in the management of zygomatico-maxillary complex fractures, Singh et al. (2011).
Otolaryngol Head Neck Surg. 2011 Dec;145(6):924-9.
https://doi.org/10.1177/0194599811421750

Abstract
Objective: The present study was undertaken to evaluate and analyze the efficacy of bioresorbable plates and screws in internal fixation of zygomatico-maxillary complex (ZMC) fractures and to evaluate the incidence of complications associated with the procedure.

Study design: Case series with planned data collection.

Setting: Pt BD Sharma University of Health Sciences.

Subject and methods: A total of 14 patients with isolated ZMC fractures were included, and exclusion of grossly comminuted, pathological, and infected fractures was done. Open reduction internal fixation was done with biodegradable plates and screws. All patients were reviewed clinically and radiographically at regular follow-up. Occlusion, stability of fracture segments, anesthesia or paresthesia of the infraorbital nerve region, and various complications were assessed periodically.

Results: Fourteen patients with 34 fracture sites were included in the study. Intraoperatively, there were 2 incidences of screw head fracture. As observed clinically, there was complete stability of fracture segments, and no maxillomandibular fixation was required postoperatively. Paresthesia of the infraorbital nerve was present in 5 patients, but the sensation recovered completely in the first 3 months after surgery. The mean pain score was 3 on a visual analogue scale. In 1 case, ectropion developed, and dehiscence occurred in another patient in the early postoperative period. Postoperative radiographs were evaluated for the accuracy of fracture reduction and stability of fixation.

Conclusion: The biodegradable osteosynthesis system exhibits adequate strength and has negligible complications. This system is technique sensitive with satisfactory results in the management of mild to moderately displaced ZMC fractures.

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Fractured facial bone reduction and resorbable plate fixation using tapper, Kim and Kim (2011).
J Craniofac Surg. 2011 Jul;22(4):1215-8.
https://doi.org/10.1097/scs.0b013e31821c0d84

Abstract
A resorbable fixation system has many advantages, but there are complicated procedures to be accomplished to fix a resorbable plate. The complicated procedures in the fixation of a resorbable plate make the operation for facial fractures more difficult and can result in extended operation time and incomplete reduction or fixation. For these reasons, we suggest a new way of using a tapper that can make the surgery more simple and accurate than before. After the resorbable plate is properly located above the fractured site, a hole on the fracture fragment is made by drill, and the tapper is inserted into the hole. When the tapper is inserted at the proper depth, the fracture fragment can be reduced to right place by handling the inserted tapper. Then, the tapper is inserted to the end, and the handle is split. While the inserted tapper acting as a temporary metal screw is placed, another hole is made at nearby site and the screw is inserted. Next, the inserted tapper acting as a temporary metal screw is removed, and another screw is inserted into the hole from which the tapper was removed. From October 2006 to April 2008, we applied this procedure to 106 facial bone fractures in 68 patients, and no major complications were noted. In conclusion, we tried to make the operation more simple and accurate by using the tapper as an instrument for reduction and fixation of fracture fragment.

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Equivalence randomized controlled trial of bioresorbable versus titanium miniplates in treatment of mandibular fracture: a pilot study, Bhatt et al. (2010).
J Oral Maxillofac Surg. 2010 Aug;68(8):1842-8.
https://doi.org/10.1016/j.joms.2009.09.005

Abstract
Purpose: The present study was undertaken to test bioresorbable fixation versus titanium for equivalence in terms of clinical union and complications using the American Association of Oral and Maxillofacial Surgeons parameters of care. The study design was a randomized, controlled, equivalence trial.

Materials and methods: A total of 40 patients were enrolled and allocated to the titanium group and bioresorbable group using a computerized randomization table. All were plated using standard plating principles. In the bioresorbable group, 2 weeks of maxillomandibular fixation was also used. Evaluation of the study endpoint was done at 8 weeks postoperatively. For statistical analysis, the upper limit of the 95% confidence interval was calculated for failure to achieve the primary outcome variable and compared with the maximal clinically acceptable difference between the standard and test modalities in the failure to achieve clinical union (delta). Delta was predetermined as 2%. The other complications were tested for significance using Fisher’s exact test.

Results: Of the 40 patients, 21 were in the titanium group and 19 were in the bioresorbable group, with 20 men and 1 woman in the titanium group and 18 men and 1 woman in the bioresorbable group. The mean age was 28.7 years in the titanium group and 26.6 years in the bioresorbable group. In the titanium group, the complications noted were nonunion in 0%, malocclusion in 7.7%, continued postoperative swelling in 0%, chronic pain in 2%, infection in 5.2%, an inability to chew hard food after 8 weeks in 7.7%, the need for alternative treatment in 0%, and the need for reoperation in 31%. In the bioresorbable group, the complications were nonunion in 4.17%, malocclusion in 11.1%, swelling in 8.3%, chronic pain in 37.5%, infection in 0%, an inability to chew hard food in 11.1%, the need for alternative treatment in 11.1%, and need for reoperation for plate removal in 0%.

Conclusions: The small sample size did not allow any meaningful conclusion to be drawn from the present study in terms of the primary question of achieving union. Both groups matched in outcomes when evaluated only on a clinical basis. The avoidance of repeat surgery for plate removal is a definite advantage of using resorbable plates. However, the results are inconclusive in favor of any particular plating system.

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Treatment of mandibular angle fractures using a single bioresorbable miniplate, Bayat et al. (2010).
J Oral Maxillofac Surg. 2010 Jul;68(7):1573-7.
https://doi.org/10.1016/j.joms.2009.11.017

Abstract
Purpose: This study evaluated the treatment of mandibular angle fractures via a single biodegradable plate and addressed complications such as malocclusion, infection, soft tissue dehiscence, and nonunion in these patients.

Patients and methods: This prospective study consisted of 19 fractures in 19 patients (18 males and 1 female) with unilateral fractures of the mandibular angle treated by open reduction and rigid internal fixation using 1 biodegradable plate through an intraoral incision. The resorbable plates and screws used consisted of an amorphous injection molded copolymer of L-lactide/D-lactide/trimethylene carbonate (Inion CPS System, Tampere, Finland). Light elastic traction was placed for 14 days postoperatively and patients were followed after operation at 1, 4, 8, and 24 weeks. Panoramic and posteroanterior views of the mandible were taken for evaluation of union.

Results: Clinical and radiographic evaluation indicated union of all fractures after 24 weeks. Three of the patients (15.7%) treated with single biodegradable plate experienced some complications. All the complications were minor and treated in the office. Two patients with infection were treated with oral antibiotic administration without plate removal. One patient with mild malocclusion was treated with elastic traction. There were no cases of nonunion or dehiscence.

Conclusion: Based on this limited series of patients, the use of a single biodegradable plate for unilateral mandibular angle fractures is a reliable fixation technique with minor complications.

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A use of poly-L-lactide, D-lactide sheet on posterior orbital floor fracture, Hwang et al. (2010).
J Craniofac Surg. 2010 Jul;21(4):1221-3.
https://doi.org/10.1097/scs.0b013e3181e17a30

Abstract
We present the cases of orbital posterior wall fractures that were fixed with poly-l-lactide, D-lactide (PLDLA) sheets. Poly-L-lactide, D-lactide sheet (0.5-mm thickness) was shaped exactly to fit to the area of orbital floor, and then an extended 1 cm was bent across on the infraorbital rim. That part was fixed with 2 absorbable screws to prevent the sheet from crumpling. Orbital floor fractures of 6 patients (3 posterior-one-half defects and 3 posterior-two-thirds defects) were repaired using PLDLA sheets. Diplopia in 5 patients before surgery was improved, usually within 6 months postoperatively. Clinical enophthalmos was not appreciated in any patient. However, preoperative exophthalmometry measured -1.3 +/- 0.3 mm and postoperatively -0.4 +/- 0.2 mm, respectively. Poly-l-lactide, d-lactide sheet is applicable to safely repair the orbital posterior floor fracture.

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Comparison of the supporting strength of a poly-L-lactic acid sheet and porous polyethylene (Medpor) for the reconstruction of orbital floor fractures, Hwang and Kim (2010).
J Craniofac Surg. 2010 May;21(3):847-53.
https://doi.org/10.1097/scs.0b013e3181d7f2ff

Abstract
The aim of this study was to elucidate the supporting strength of the curved poly-L-lactic acid (PLLA) sheet and porous polyethylene (Medpor) for reconstruction of orbital floor fractures. For one-half and two-thirds orbital floor fractures, reconstruction was performed using the PLLA sheet and Medpor. The PLLA sheet was molded to fit the orbital floor (concavity). The anterior portion (1 cm) was curved to fit the inferior orbital rim and fixed with a screw. Medpor was designed to fit the orbital floor. A screw was fixed 6 mm away from the anterior border of the orbital floor. Each implant was hung by wire, and the degree of sagging of the implant was measured using micrometers by the power of a force gauge. For one-half orbital floor fractures, the power of the PLLA sheet to sag 5 mm was 2.46 (SD, 0.14) N, and that of Medpor was 0.59 (SD, 0.04) N. The power of the PLLA sheet to sag 10 mm was 6.9 (SD, 0.14) N, and that of Medpor was 1.52 (SD, 0.16) N. For two-thirds orbital floor fractures, the power of the PLLA sheet to sag 5 mm was 1.79 (SD, 0.24) N, and that of Medpor was 0.39 (SD, 0.04) N. For 10 mm of sagging, the power of the PLLA sheet was 5.61 (SD, 0.29) N, and that of Medpor was 0.94 (SD, 0.09) N. For sagging of 15 mm, the power of the PLLA sheet was 8.99 (SD, 0.16) N, and that of Medpor was 2.98 (SD, 0.24) N. The PLLA sheet was irreversibly bent when the force reached approximately 8 to 9 N. For Medpor, the degree of sagging during the early stage was larger than at the later stage. In all situations, the supporting power of the PLLA sheet was greater than that of Medpor. The differences were significant in all situations (P = 0.000). The degree of sagging in one-half orbital floor fractures was 2.87 mm for the PLLA sheet and 7.96 mm for Medpor. There was an increased orbital volume of 0.4 mL with the PLLA sheet and 1.19 mL for Medpor. The predicted enophthalmos was 0.41 mm with the PLLA sheet and 1.07 mm with Medpor. The degree of sagging for the two-thirds orbital floor fractures was 4.28 mm for the PLLA sheet and 11.47 mm for Medpor. The increased orbital volume was 0.78 mL for the PLLA sheet and 2.22 mL for Medpor. The predicted enophthalmos was 0.73 mm with the PLLA sheet and 1.93 mm with Medpor. The predicted enophthalmos was below 2 mm with both the PLLA sheet and Medpor for reconstruction of orbital floor fractures; however, it was near 2 mm with Medpor in reconstruction of two-thirds orbital floor fractures. The results of this study show that the PLLA sheet and Medpor were sufficient for reconstruction of one-half and two-thirds orbital floor fractures with a defective posterior part. However, the supporting power of the PLLA sheet was stronger than that of Medpor.

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The fate of an extruded biodegradable mandibular plate, Nazim (2009).
Journal of Plastic Reconstructive and Aestethic Surgeons, 2009; 62(6): 850-852.
https://doi.org/10.1016/j.bjps.2008.04.068

After the introduction of biodegradable plates and screws for maxillo-facial fixation over the last decade, there have been many studies related to safety, indications, contraindications, complications, outcomes and other aspects of clinical use. 1 , 2 , 3 , 4 , 5 Degradation by converting into CO2 and H2O via bulk hydrolysis by the liver removes the need of re-operation to remove the plates and screws. Problems associated with metal fixation such as growth disturbances in young children, hypersensitivity to cold exposure, interference with radiological evaluation, stress shielding and bone resorption are no longer considerations.

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Do we have to dissect infraorbital nerve from periorbita in orbital floor fracture?, Hwang and Hwang (2009).
J Craniofac Surg. 2009 Jul;20(4):1260-2.
https://doi.org/10.1097/scs.0b013e3181acde42

Abstract
The aim if this study was to see whether we have to dissect the infraorbital nerve from periorbita in orbital floor fractures.Orbital floors were reconstructed in 174 patients. Among them, 31 patients were treated with horseshoe-shaped synthetic sheets. Preoperative and postoperative findings including hypesthesia, diplopia, Hertel exophthalmometry, and occurrence of complications were checked.After the subciliary incision through skin and orbicularis oculi muscle, the skin-muscle flap was elevated just superficial to the orbital septum to the arcus marginalis. The periosteum was incised and elevated to expose the fracture site. The orbital branch of the infraorbital artery was identified. The periorbita was not separated from the infraorbital nerve, and the orbital branch of the infraorbital artery was preserved. The sheet was trimmed in horseshoe shape as the cleft fits to the infraorbital groove.On physical examination before surgery, diplopia was the most common (58.1%) associated complication, followed by hypesthesia (35.5%), limited ocular movement (9.7%), enophthalmos (3.2%), and hematoma (3.2%).Even if the fracture site is the posterior half, the periorbita does not have to be separated from the infraorbital nerve to avoid injury of the orbital branch of the infraorbital artery. Instead, the fracture site might be covered by a horseshoe-shaped sheet.

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Medial orbital wall reconstruction through subciliary approach: revisited, Hwang et al. (2009).
J Craniofac Surg. 2009 Jul;20(4):1280-2.
https://doi.org/10.1097/scs.0b013e3181ae1761

Abstract
The aim of this study is to determine the safety and complication of subciliary approach through the retrospective review of our experiences. From 2005 through 2008, the subciliary skin-muscle flap methods were used in 30 patients undergoing medial orbital wall reconstruction. Preoperative and postoperative ophthalmic findings including diplopia, Hertel exophthalmometry, and occurrence of complications were checked. Resorbable polylactic acid sheet or porous polyethylene sheet was trimmed and molded in L shape, vertical portion to cover the medial wall defect and horizontal portion for stability in orbital floor.In the follow-up of diplopia, half of the patients (3 cases) presenting with diplopia improved during the first month of follow-up, and all of them improved by 6 month. For hypesthesia, all patients improved by 3 months. Enophthalmos of 1 patient improved after operation and did not recur. No patients complained of visible scar 6 months postoperatively, and no ectropion was observed.We think that medial orbital wall could be reconstructed safely through skin-muscle flap subciliary approach without resulting in ectropion or lacrimal canaliculus injury.

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Analysis of orbital bone fractures: a 12-year study of 391 patients, Hwang et al. (2009).
J Craniofac Surg. 2009 Jul;20(4):1218-23.
https://doi.org/10.1097/scs.0b013e3181acde01

Abstract
This retrospective study evaluates 391 patients with orbital bone fractures from a variety of accidents that were treated at the department of Plastic and Reconstructive Surgery, Inha University Hospital, Incheon, South Korea, between February 1996 and April 2008. The medical records of these patients were reviewed and analyzed to determine the clinical characteristics and treatment of the orbital bone fractures.The following results were obtained. The mean age of the patients was 31.1 years, and the age range was 4 to 78 years. The most common age group was the third decade of life (32.5%). There was a significant male predominance in all age groups, with a ratio of 4.43:1. The most common etiology was violent (assault) or nonviolent traumatic injury (57.5%) followed by traffic accidents (15.6%) and sports injuries (10.7%).The most common isolated orbital bone fracture site was the orbital floor (26.9%). The largest group of complex fractures included the inferior region of the orbital floor and zygomaticomaxilla (18.9%). Open reduction was performed in 63.2% of the cases, and the most common fracture reconstruction material was MEDPOR (56.4%) followed by a resorbable sheet (41.1%). The postoperative complication rate was 17.9%, and there were no statistically significant differences among the reconstruction materials with regard to complications. During follow-up, diplopia, hypoesthesia, and enophthalmos occurred as complications; however, there was no significant difference between porous polyethylene sheet (MEDPOR) and resorbable sheet groups.Long-term epidemiological data regarding the natural history of orbital bone fractures are important for the evaluation of existing preventative measures and for the development of new methods of injury prevention and treatment.

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Degradative and mechanical properties of a novel resorbable plating system during a 3-year follow-up in vivo and in vitro, Nieminen et al. (2010).
J Mater Sci Mater Med. 2008 Mar;19(3):1155-63.
https://doi.org/10.1007/s10856-007-3082-x

Abstract
We tested the tissue reactions and mechanical strength of a novel biodegradable craniomaxillofacial plating system, Inion CPS, in the course of degradation. Plates and screws composed of L-lactide, D-lactide and trimethylene carbonate were implanted to the mandible and dorsal subcutis of 12 sheep. The animals were sacrificed at 6-156 weeks. Histological evaluation was done using paraffin and methylmetacrylate techniques. Degradative and mechanical properties during the follow-up were measured both of in vivo and in vitro implants. In light microscopy, the in vivo implant material began to fragment at 52 weeks and could not be detected at 104 weeks. No significant foreign body reactions were seen in the mandibles. The dorsal subcutis disclosed mild reactions, which were, however, not of clinical significance. The implants in vitro maintained their entire mass for 26 weeks and lost 63-80% of the mass by week 104. The inherent viscosity of the implants in vitro and in vivo diminished uniformly. The screws retained their shear strength for 12-16 weeks. The plates maintained their tensile strength for at least 6 weeks. The maximum capacity of the plates in 3-point bending tests diminished gradually by 87% in 26 weeks. In conclusion, the plates and screws examined maintain adequate strength for the healing period of a bone fracture or osteotomy, producing no harmful foreign body reactions.

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Stability and morbidity of Le Fort I osteotomy with bioresorbable fixation: a randomized controlled trial, Cheung et al. (2008).
Int J Oral Maxillofac Surg. 2008 Mar;37(3):232-41.
https://doi.org/10.1016/j.ijom.2007.09.169

Abstract
A randomized controlled clinical trial was conducted to compare the use of bioresorbable and titanium mini-plates and screws in Le Fort I maxillary osteotomies for evaluation of clinical morbidity and stability. Forty patients requiring Le Fort I osteotomies were randomly assigned to two groups. One group underwent bioresorbable mini-plate fixation and the other titanium mini-plate fixation. Stability of the maxilla was determined by serial cephalometric analysis at 2 and 6 weeks and at 3, 6 and 12 months postoperatively. Subjective and objective assessment of clinical morbidity was made prospectively. There were no differences in complications between the two fixation materials. Maxillae with bioresorbable fixation were significantly more mobile at the second postoperative week. Bioresorbable plates were initially more easily palpable, but their palpability decreased with time. Titanium plates became significantly more palpable at the 1-year follow-up. There was no difference in neurosensory disturbance between groups. Patients with bioresorbable plate fixation showed significantly more upward displacement in anterior maxilla following impaction and posterior maxilla following downgrafting from the 2nd to 6th postoperative week. The horizontal and angular relapses in the two groups were comparable. Le Fort I osteotomy with bioresorbable fixation results in no greater morbidity than with titanium fixation up to 1 postoperative year.

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INION compared with titanium osteosynthesis: a prospective investigation of the treatment of mandibular fractures, Leonhardt et al. (2008).
Br J Oral Maxillofac Surg. 2008 Dec;46(8):631-4.
https://doi.org/10.1016/j.bjoms.2008.04.021

Abstract
We prospectively studied two groups of 30 patients to assess the outcome of treatment of mandibular fractures with the biodegradable INION system compared with osteosynthesis with titanium miniplates. The degree of occlusion, wound healing, and swelling, were noted preoperatively and at 1 week, 6 weeks, and 6 months postoperatively. All fractures healed uneventfully, both clinically and radiologically, and independently of the osteosynthesis used. We found no long-term disturbance of occlusion, but there were twice as many malocclusions in the INION group at one week. We now use a 3-5 day period of postoperative elastic intermaxillary fixation (IMF) to prevent material deformities. Both groups developed problems with wound healing; with INION adequate soft tissue closure combined with appropriate positioning of the plates prevented this. At 6 months a dense swelling developed in some patients in the INION group as a result of biodegradation of the plates. INION plates were biocompatible and strong enough to treat mandibular fractures.

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Bicortical biodegradable screws for rigid fixation of traumatic sagittal split mandibular fracture, Canter and Mavili (2007).
J Craniofac Surg. 2007 May;18(3):626-9.
https://doi.org/10.1097/scs.0b013e31805344f4

Abstract
Rigid fixation is the most important issue in the bone healing process. Although internal metallic bone fixation has become increasingly popular over the past 10 years, the presence of several potential problems of metallic bone implants with the popularity of the use of biodegradable plates and screws for craniomaxillofacial fixation have increased in the last 10 years. Rigid fixation of bony fragments was achieved by bicortical applied biodegradable screws in a patient with a sagittal oblique mandibular fracture. Precise bone reduction was maintained with bicortical applied biodegradable screws in the postoperative period. The postoperative period was uneventful and the patient retained the intraoperatively achieved perfect occlusion within a 9-month follow-up period. In this particular case, the advantages of use of resorbable fixation systems are combined with the advantages of bicortical screw fixation of split osteotomy without sacrificing the stability of rigid fixation.

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Resorbable plates for the fixation of mandibular fractures: a prospective study, Laughlin et al. (2007).
J Oral Maxillofac Surg. 2007 Jan;65(1):89-96.
https://doi.org/10.1016/j.joms.2005.10.055

Abstract
Purpose: The hypothesis for this prospective evaluation is that resorbable plates are equal to the performance of titanium 2-mm plates, regarding healing of the fracture with bone union and restoration of function. To prove this hypothesis, specific end points will be compared with literature norms for titanium 2-mm miniplate rigid fixation. The primary end point variable for this analysis is the union of the fracture and return to normal function. Secondary end point variables included the incidence of complications such as infection, malunion with malocclusion, soft tissue dehiscence, the need for revision surgery, specific technical challenges, operative time, and the learning curve for the surgeon.

Patients and methods: This prospective study consisted of a sequential enrollment of 50 fractures that met the inclusion criteria of having a fracture of the mandibular body, symphysis, angle, or ramus, and required an open reduction and internal fixation for stabilization and repair. The resorbable plates and screws used consisted of an amorphous injection molded copolymer of L-lactide/D-lactide/trimethylene carbonate (Inion CPS system, Tampere, Finland). Data were collated and compared with literature norms for titanium plates and also compared with nonrigid fixation data from a prospective study performed on a similar population in the same institution.

Results: Clinical and radiographic evaluation indicated union of all fractures at the eighth follow-up visit. Three sites (6%) noted to have clinical signs of infection were treated immediately upon presentation, with fracture union by 8 weeks. There was no need for revision surgery in this series of patients; 12 screw heads fractured during screw placement and were immediately replaced without significant fracture sequelae.

Conclusion: Based on this limited series of patients, the hypothesis formulated for this study was validated.

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Reconstruction of traumatic orbital floor fractures with resorbable mesh plate, Tuncer et al. (2007).
J Craniofac Surg. 2007 May;18(3):598-605.
https://doi.org/10.1097/01.scs.0000246735.92095.ef

Abstract
Various materials such as autogenous bone, cartilage and alloplastic implants have been used to reconstruct orbital floor fractures. A new material is needed because of disadvantages of nonresorbable alloplastic materials and difficulties in harvesting autogenous tissues. In this study safety and value of the use of resorbable mesh plate in the treatment of orbital floor fractures are discussed. Between 2002 and 2004 a total of 17 maxillofacial trauma patients complicated with orbital floor fractures were treated with resorbable mesh plate through subciliary or transconjunctival incisions. Pure blow-out fractures were determined in 6 patients and 11 patients had accompanying maxillofacial fractures. Resorbable plate was easily shaped to fit to the orbital floor by cutting with scissors. Patients were evaluated clinically and with computed tomography scans preoperatively and at 3-, 6- and 12-month intervals postoperatively. Twelve patients had preoperative enophthalmos. Two patients had diplopia that was corrected postoperatively. In all 17 cases there was no evidence of infection, diplopia and gaze restriction postoperatively. Scleral show appeared in three patients by the second postoperative week but resolved totally within 3 to 6 weeks except one patient. In this patient anterior displacement of mesh was evident which caused ectropion and enophthalmos and required re-operation. No any other mesh related problems were seen at 15 months mean follow-up time. The advantage of the resorbable mesh system in orbital floor fracture is the maintenance of orbital contents against herniation forces during the initial phase of healing and then complete resorption through natural processes after its support is no longer needed. Our experience represents that resorbable mesh is a safe and effective material for reconstruction of the selected, non-extensive orbital floor fractures.

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Frontal cranial modeling using endocranial resorbable plate fixation in 27 consecutive plagiocephaly and trigonocephaly patients, Salokorpi et al. (2015).
Childs Nerv Syst. 2015 Jul;31(7):1121-8.
https://doi.org/10.1007/s00381-015-2657-y

Abstract
Introduction: Premature ossification of coronal and metopic sutures is treated by fronto-orbital remodeling. Such operations require stable fixation of the reshaped cranial bones. Currently, biodegradable plating systems are used to provide sufficient stability over the time that takes for the osteotomies to ossify. Plates that are placed traditionally on the outer surface of the cranium are often palpable and even visible through the thin overlying skin, compromising the cosmetic results of these operations. Improved aesthetics could be achieved by placing the plates endocranially.

Purpose: This study aimed to evaluate endocranial resorbable plate fixation and its clinical and radiographic results in frontal remodeling cranioplasty for plagiocephaly and trigonocephaly patients with follow-up sufficiently long for the plates to have been completely resorbed.

Methods: A poly(lactide-co-glycolide) (PLGA) resorbable plating system was used on the inner aspect of frontal bone in 27 patients treated for coronal and metopic craniosynostoses. The outcome was evaluated at follow-up visits. The mean follow-up was 79.2 months.

Results: Three patients had complications that required reoperations. None of these complications were related to the endocranial location of the plates. There were no problems with ossification of the osteotomy sites. All but one patient’s outcome was judged as good or excellent.

Conclusion: Placement of resorbable fixation on the endocranial surface of the calvarial bones is safe, stable, and results in satisfactory aesthetics without interfering with the ossification of the cranial bones.

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Distraction osteogenesis with pivot plate in the treatment of scaphocephaly, Nam et al. (2011).
J Craniofac Surg. 2011 Jan;22(1):96-9.
https://doi.org/10.1097/scs.0b013e3181f6c5ca

Abstract
In scaphocephaly, traditional distraction osteogenesis increases only the bitemporal width. We describe distraction osteogenesis with a pivot plate for scaphocephaly, which not only increases the bitemporal width but also decreases the anteroposterior length. Three patients with scaphocephaly were treated using distraction osteogenesis with a pivot plate between January 2005 and June 2006. These children underwent cranial reshaping by gradual distraction using an external distraction device and pivot plate. The distraction rate was 1 mm/d, and the latency period was 5 days. The follow-up period after distraction osteogenesis ranged from 16 to 24 months. No specific complications, such as accidental removal of the distraction devices, infection, or neurologic problems in any patient, occurred. The mean distraction was 45 mm. The mean cranial index was 73.6. Distraction osteogenesis for scaphocephaly is still in the development stage, but it is becoming accepted as a useful method because of its many advantages. Distraction osteogenesis with a pivot plate for scaphocephaly is better than other distraction osteogenesis techniques because it induces increased bitemporal width and decreased anteroposterior length synchronously.

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Surgical treatment of metopic synostosis, Hormozi et al. (2011).
J Craniofac Surg. 2011 Jan;22(1):261-5.
https://doi.org/10.1097/scs.0b013e3181f7b80c

Abstract
Metopic synostosis is characterized by keel-shaped forehead (trigonocephaly), prominent midline ridge of the forehead, bitemporal narrowing, bilateral retrusion of supraorbits, egg-shaped orbits, low nasal dorsum, and reduced volume of the anterior cranial fossa. The mainstay treatment is early surgical intervention before the age of 12 months, which usually consists of bifrontal craniotomy with bilateral recontouring, lateral advancement, and lateral displacement of the superior orbital rims. Here, we have developed a new simplified technique for surgical treatment of trigonocephaly. A total of 60 cases of trigonocephaly were operated on between January 1995 and January 2010 by the first author. Surgical outcomes were evaluated 6 months after surgery using postoperative photographs and clinical examination notes, and scaling was made using the Whitaker classification. The evaluation showed that 85% of them were in class I, 11.6% were in class II, and 3.3% were in class III. No case was in class IV. Only the last 10 cases received the new surgical technique, and all were in class I. Complication rate was 38.3% for all cases and was only 20% for the last 10 cases, that is, the new technique group. Revision rate for trigonocephaly surgery was 13.3%, and the most common reason was hardware removal. None of the patients from the new technique group underwent revision surgery. We believe that our new technique is fast and easy, can provide sufficient bone graft, and is more useful for older patients (>1 y). Early postoperative results have been promising.

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Biodegradation of Inion fast-absorbing biodegradable plates and screws, Losken et al. (2008).
J Craniofac Surg. 2008 May;19(3):748-56.
https://doi.org/10.1097/scs.0b013e31816aab24

Abstract
Biodegradable plates and screws are recommended for use in surgery of the craniofacial skeleton of children. To be effective and not interfere with growth of the child’s skull, the plates must biodegrade sufficiently to release the holding power of the plate and screw within 1 year. It is also essential that excessive foreign body reaction and cyst formation does not occur when the plates and screws biodegrade. The purpose of this experimental study was to evaluate the rate of biodegradation of Inion CPS Baby biodegradable plates and screws under different clinical circumstances in the rabbit craniofacial skeleton and evaluate their efficacy for use in pediatric craniofacial surgery. Foreign body reaction would be evaluated. Inion baby plates and screws were tested in a rabbit model. Plates were applied to the frontal bone, over a bony defect of the parietal bone, to a nasal bone fracture, and inserted in the subcutaneous space over the occipital bone in thirty 6-week-old rabbits. Six rabbits were euthanized at 9, 12, 15, and 18 months’ postoperative time point and examined for residual plates and screws. Bone from each surgical site was excised, fixed by immersion in 10% neutral-buffered formalin, decalcified in Immunocal solution, and examined by 7-microm paraffin sections stained with hematoxylin and eosin. At 9 months, the plates and screws had effectively biodegraded and no longer had holding power on the bones. Fragmentation of the implant material was noted. Residual implant material was still present on gross and histologic examination in rabbits at 9, 12, 15, and 18 months. Residue of a screw was still palpable in 1 rabbit at 18 months. There was no evidence of cyst formation in any of the examined specimens. Macrophages and giant cells were present in most of the specimens at 9, 12, 15, and 18 months. Findings from the current study revealed a relative short resorption time (9 mo) and normal inflammatory sequelae in an adult rabbit model. These findings suggest that these plates may be used safely in fixing the pediatric craniofacial skeleton.

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Effective correction of frontal cranial deformities using biodegradable fixation on the inner surface of the cranial bones during infancy, Serlo et al. (2007).
Childs Nerv Syst. 2007 Dec;23(12):1439-45.
https://doi.org/10.1007/s00381-007-0470-y

Abstract
Purpose: Fixation of cranial bones in pediatric craniofacial surgery with biodegradable materials has developed into an accepted method. However, placing the fixation material on the outer surface of the cranial bone at the frontal cranium in infants can result in suboptimal cosmetic outcomes, as the plates and screws can be palpable. The placement of resorbable fixation devices on the inner surface of the skull would allow for less obvious fixation beneath the skin with a potentially superior cosmetic result. The authors report the use of such resorbable fixation devices on the inner or endocranial aspect of the cranium which appears to be novel.

Materials and methods: Ten patients with the mean age of 14 months (range 7-35 months) were treated with cranial remodeling using poly(lactide-co-glycolide) (PLGA) biodegradable fixation on the inner surface of the cranial bones. Five patients had trigonocephaly, four plagiocephaly, and one brachycephaly. All patients had 3D computed tomography (CT) and clinical photographs done preoperatively and postoperatively at follow-up. The outcome was judged at follow-up by clinical evaluation, photographs, 3D CT, and interview of the parents. The mean follow-up time was 3.5 years (range 0.5-6 years).

Results: The primary recovery was uneventful in all cases. No wound infection occurred, but one patient had a minor skin necrosis which required a single revision operation to correct. The cosmetic outcome was scored as excellent, good, fair, or poor. There was no case with delayed union. Seven out of ten cases were judged as excellent and three as good, none as fair or poor.

Conclusions: The use of resorbable PLGA fixation devices on the inner aspect of the skull appears to provide a satisfactory cosmetic result in this small preliminary group of pediatric patients. Further long-term study of these materials in this specific location in a larger patient group is needed.

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Treatment of a mandibular fracture with biodegradable plate in an infant: report of a case, Senel et al. (2006).
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006 Apr;101(4):448-50.
https://doi.org/10.1016/j.tripleo.2005.07.020

Abstract
Mandibular fractures in infants are rare. Different methods have been described for treatment of fractures of the mandible in infants. Internal fixation of a mandibular fracture with a biodegradable plate in an 8-month-old baby is described. In addition, choices of treatment modality in such cases are discussed.

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