Segment Stability in Bimaxillary Orthognathic Surgery After Resorbable Poly(L-lactide-co-glycolide) versus Titanium Osteosyntheses

Systematic mapping review of orthognathic surgery

STUDY DESIGN

Systematic mapping review AIM AND SCOPE: The objective of this mapping review was to identify, describe, and organize clinical research currently available from systematic reviews and primary studies regarding co-interventions and different surgical modalities used in orthognathic surgery (OS) and their outcomes.

METHODS

Systematic reviews (SRs), randomized controlled trials, and observational studies that evaluated perioperative OS co-interventions and surgical modalities were identified in an exhaustive search of MEDLINE, EMBASE, Epistemonikos, Lilacs, Web of Science, and CENTRAL. Grey literature was also screened.

RESULTS

Included were 35 SRs and 253 primary studies, 103 from SRs, and another 150 identified in our search. Overall, SR quality was rated as critically low, with only two SRs rated as of high quality. 19 questions on population, interventions, comparisons, and outcomes (PICO) extracted from the SRs focused on osteosynthesis methods, surgical cutting devices, and use of antibiotics, corticosteroids, and induced hypotension. Also identified were 15 research gaps. Evidence bubble maps were created to graphically depict the available evidence.

CONCLUSION

Future high-quality research, both primary and secondary, is needed to address the knowledge gaps identified in this systematic mapping review.

A Narrative Review of u-HA/PLLA, a Bioactive Resorbable Reconstruction Material: Applications in Oral and Maxillofacial Surgery

The advent of bioresorbable materials to overcome limitations and replace traditional bone-reconstruction titanium-plate systems for bone fixation, thus achieving greater efficiency and safety in medical and dental applications, has ushered in a new era in biomaterial development. Because of its bioactive osteoconductive ability and biocompatibility, the forged composite of uncalcined/unsintered hydroxyapatite and poly L-lactic acid (u-HA/PLLA) has attracted considerable interest from researchers in bone tissue engineering, as well as from clinicians, particularly for applications in maxillofacial reconstructive surgery. Thus, various in vitro studies, in vivo studies, and clinical trials have been conducted to investigate the feasibility and weaknesses of this biomaterial in oral and maxillofacial surgery. Various technical improvements have been proposed to optimize its advantages and limit its disadvantages. This narrative review presents an up-to-date, comprehensive review of u-HA/PLLA, a bioactive osteoconductive and bioresorbable bone-reconstruction and -fixation material, in the context of oral and maxillofacial surgery, notably maxillofacial trauma, orthognathic surgery, and maxillofacial reconstruction. It simultaneously introduces new trends in the development of bioresorbable materials that could used in this field. Various studies have shown the superiority of u-HA/PLLA, a third-generation bioresorbable biomaterial with high mechanical strength, biocompatibility, and bioactive osteoconductivity, compared to other bioresorbable materials. Future developments may focus on controlling its bioactivity and biodegradation rate and enhancing its mechanical strength.

Efficacy and morbidity of biodegradable versus titanium osteosyntheses in orthognathic surgery: A systematic review with meta-analysis and trial sequential analysis

Titanium osteosynthesis is currently the gold standard in orthognathic surgery. Use of biodegradable osteosyntheses avoids removal of plates/screws in a second operation. This systematic review aimed to assess the efficacy and morbidity of biodegradable vs. titanium osteosyntheses in orthognathic surgery (PROSPERO CRD42018086477). Patients with syndromic disorder(s) and/or cleft lip/palate were excluded. Randomised, prospective and retrospective controlled studies were searched for in nine databases (February 2021). The time periods perioperative, short‐term, intermediate, long‐term, and overall follow‐up were studied. Meta‐analyses were performed using random‐effects models. A total of 9073 records was assessed, of which 33 were included, comprising 2551 patients. Seven RCTs had ‘some concerns’ while another seven RCTs had ‘high’ risk of bias (Cochrane‐RoB2). No differences in malunion (qualitative analyses), mobility of bone segments [RR 1.37 (0.47; 3.99)], and malocclusion [RR 0.93 (0.39; 2.26)] were found. The operative time was longer in the biodegradable group [SMD 0.50 (0.09; 0.91)]. Symptomatic plate/screw removal was comparable among both groups [RR 1.29 (0.68; 2.44)]. Skeletal stability was similar in most types of surgery. Biodegradable osteosyntheses is a valid alternative to titanium osteosyntheses for orthognathic surgery, but with longer operation times. Since the quality of evidence varied from very low to moderate, high‐quality research is necessary to elucidate the potential of biodegradable osteosyntheses.

Resorbable Versus Titanium Fixation of Le Fort I Osteotomy

Resorbable and titanium systems have been used in maxillary fixation. The aim of this review was to evaluate stability and morbidity of Le Fort I osteotomy by comparing both systems. It was performed in 11 databases, and reported according to preferred reporting items for systematic reviews and meta-analysis. Randomized and nonrandomized clinical trials, and retrospective comparative studies with patients who underwent nonsegmented Le Fort I osteotomy were included. Eleven articles were selected, with a total of 262 patients treated with resorbable and 252 with titanium fixation. The meta-analysis showed that when measured at point A, horizontal stability was 0.06 mm (95% confidence interval [CI] -0.19, 0.30), vertical stability for impaction was -0.43 mm (95% CI -0.94, 0.07), and for inferior repositioning was -1.29 mm (95% CI -2.62, 0.04). Morbidity was similar in the groups. Regarding infection, resorbable presented an absolute risk (AR) = 0.032, and titanium an AR = 0.025 (P = 1.0). For soft tissue reaction, an AR = 0.120 was shown for resorbable, and an AR = 0.132 for titanium (P = 0.85). Removal of fixation showed an AR = 0.024 for resorbable, and an AR = 0.025 for titanium (P = 1.0). Based on these results, resorbable and metal fixation systems seem to be equivalent with respect to stability and morbidity. This review was limited by the quality of the studies. Future studies should address these quality limitations to improve comparison between these 2 fixation approaches.

Bone healing after Le Fort I osteotomy with SSRO, using uHA/PLLA plates and screws, in class II and III patients

PURPOSE

The purpose of this study was to compare bone healing after Le Fort I osteotomy with sagittal split ramus osteotomy (SSRO) in class II and class III patients.

PATIENTS AND METHODS

The subjects consisted of 46 Japanese class II and III patients. Le Fort I osteotomy was performed in combination with SSRO. They were divided into two groups (23 class II cases and 23 class III cases). Four absorbable plates (uncalcined and unsintered hydroxyapatite and poly-l-lactic acid - uHA/PLLA) and screws were used to fix the maxillary segment in all patients, in the same manner. Postoperative computed tomography (CT) was analyzed for all patients at 1 week and 1 year postoperatively. The anterior and lateral areas between the maxillary segments were measured using two-dimensional frontal and lateral views from the three-dimensional images reconstructed over a constant CT value.

RESULTS

There were no significant differences in the area of bone defect healing between classes II and III at 1 year postoperatively, although there were significant differences between the two groups at 1 week postoperatively (p < 0.05). Furthermore, there were no significant differences in the areas of bone defect between 1 week and 1 year postoperatively, in both groups.

CONCLUSION

Using measurements based on CT value threshold within 1 year after Le Fort I osteotomy, this study suggests that the areas of bony defect in the region of the anterior and lateral walls of the maxilla do not always decrease in both classes II and III.

Comparative study on long-term stability in mandibular sagittal split ramus osteotomy: hydroxyapatite/poly-l-lactide mesh versus titanium miniplate

Background

Resorbable devices have recently been adopted in the field of orthognathic surgery with controversies about their postoperative skeletal stability. Hence, we determined the long-term skeletal stability of unsintered hydroxyapatite/poly-l-lactic acid (HA/PLLA) mesh for osteofixation of mandibular sagittal split ramus osteotomy (SSRO), and compared it with that of titanium miniplate.

Methods

Patients were divided into resorbable mesh and titanium miniplate fixation groups. A comparative study of the change in the mandibular position was performed with preoperative, 1-day, 6-month, and 2-year postoperative lateral cephalograms.

Results

At postoperative 6 months—compared with postoperative 1 day, point B (supra-mentale) was significantly displaced anteriorly in the titanium-fixation group. Moreover, at postoperative 2 years—compared with postoperative 6 months, point B was significantly displaced inferiorly in the titanium-fixation. However, the HA/PLLA mesh-fixation group did not show any significant change with respect to point B postoperatively.

Conclusions

The HA/PLLA mesh-fixation group demonstrated superior long-term skeletal stability with respect to the position of mandible, when compared with the titanium-fixation group.

Bioabsorbable osteofixation for orthognathic surgery

Orthognathic surgery requires stable fixation for uneventful healing of osteotomized bony segments and optimal remodeling. Titanium plates and screws have been accepted as the gold standard for rigid fixation in orthognathic surgery. Although titanium osteofixation is the most widely used approach, the use of bioabsorbable devices has been increasing recently. Biodegradation of bioabsorbable devices eliminates the need for a second operation to remove metal plates and screws. However, long-term stability and relapse frequency in bioabsorbable osteofixation are still insufficiently studied, especially in cases of segmental movements of great magnitude or segmental movements to a position where bony resistance exists. This paper reviews the background, techniques, and complications of bioabsorbable osteofixation and compares bioabsorbable and titanium osteofixation in orthognathic surgery in terms of skeletal stability.

Biodegradable and Titanium Osteosynthesis Provide Similar Stability for Orthognathic Surgery

PURPOSE

The purpose of this study was to test the hypothesis that there is no difference in skeletal stability and material-related complications for titanium or biodegradable fixation when used for various orthognathic surgeries.

MATERIALS AND METHODS

A systematic and electronic search of several databases with specific keywords, a reference search, and a manual search through September 2014 was performed. The inclusion criteria were clinical human studies, including randomized controlled trials, controlled clinical trials, and retrospective studies, with the aim of comparing titanium and biodegradable osteosynthesis after various orthognathic surgeries. The outcome variables of horizontal and vertical relapse using cephalometrics and material usability were statistically analyzed.

RESULTS

The initial PubMed search identified 557 studies, 22 of which met the inclusion criteria (8 randomized controlled trials, 10 controlled clinical trials, and 4 retrospective studies). No statistical difference was found between the 2 groups regarding skeletal stability after various orthognathic surgeries. There was no statistical difference with regard to wound problems, plate and screw removal, and palpability between biodegradable and titanium osteosynthesis, but there was a statistical difference with regard to intraoperative fracture of plates and screws in the biodegradable group.

CONCLUSION

The results of this meta-analysis support the hypothesis that biodegradable fixation devices offer similar skeletal stability as titanium fixation for orthognathic surgery. The results of this study also show that titanium fixation produced fewer broken screws during surgery compared with biodegradable screws.

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

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.

Segmental stability in orthognathic surgery: hydroxyapatite/Poly-l-lactide osteoconductive composite versus titanium miniplate osteosyntheses

Hydroxyapatite was included into F-u-HA/PLLA (unsintered hydroxyapatite - Poly l-lactide) composite osteosynthesis material for its documented osteoconductive capacity. This study investigates segmental retention capacities and outcome stability using F-u-HA/PLLA composite osteosyntheses in orthognathic surgery. Of fifty patients in total, 25 patients were osteofixated with F-u-HA/PLLA osteoconductive bioabsorbable osteosyntheses and compared to a group of 25 patients treated with titanium miniplates. The F-u-HA/PLLA group included 14 maxillary advancements, 4 setbacks, 13 impactions, 5 elongations at A-point; the titanium group included 20 maxillary advancements, 2 setbacks, 11 impactions and 11 elongations. In the mandible the F-u-HA/PLLA group included 13 advancements at B-point, 11 setbacks, 16 clockwise rotations and 8 counterclockwise rotations at the Gonial angle (Ar-Go-Gn); the titanium group included 9 mandibular advancements, 5 setbacks, 8 clockwise rotations and 6 counterclockwise rotations at Ar-Go-Gn. Segmental stability and relapse were assessed comparing preoperative, postoperative and follow-up roentgen cephalometrics at 22 ± 11 months on average in F-u-HA/PLLA cases, 24 ± 22 months on average in the titanium group. All absolute operative movements were nonsignificant in the F-u-HA/PLLA cases compared to the titanium osteosynthesis cases. Relapses were nonsignificant but there was greater vertical relapse in maxillary impactions with titanium osteosyntheses. Throughout this study, F-u-HA/PLLA composite osteosyntheses appeared as stable as titanium miniplates. It can therefore be concluded, although from a limited number of patients, that the investigated osteoconductive osteosynthesis can be used in a similar way to titanium miniplates in orthognathic surgery. Compared to earlier studies using other bioabsorbable polymers in the literature, F-u-HA/PLLA proved to be more stable in segmental retention.

Complications of absorbable fixation in maxillofacial surgery: a meta-analysis

BACKGROUND

The use of titanium during maxillofacial fixation is limited due to its palpability, mutagenic effects and interference with imaging, which lead to the requirement for subsequent removal. The use of a biologically absorbable fixation material will potentially eliminate these limitations. In this meta-analysis, we analyzed the complications of absorbable fixation in maxillofacial surgery.

METHODS

We performed a systematic search of PubMed, Embase, Cochrane Central Register of Systematic Reviews and Cochrane Central Register of Controlled Trials for trials published through December 2012. Data extracted from literature were analyzed with Review manager 5.0.24.

RESULTS

Relevant data was extracted from 20 studies (1673 participants) and revealed that patients in the absorbable group had significantly more complications than those in the titanium group (RR = 1.20; 95% CI: 1.02-1.42; P = 0.03) in all enrolled maxillofacial surgeries. For bimaxillary operation subgroup, the absorbable fixation group did not have a significant increase in complications when compared with the titanium group (RR = 1.89; 95% CI: 0.85-4.22; P = 0.12). There was no significant difference observed between the absorbable and titanium groups receiving a bilateral sagittal split ramus osteotomy (BSSRO) (RR = 1.45; 95% CI: 0.84-2.48; P = 0.18) and Le Fort I osteotomy (RR = 0.65; 95% CI: 0.34-1.23; P = 0.18). The combined results of the five trials revealed that the absorbable group had a significantly lower rate of complications compared to the titanium group (RR = 0.71; 95% CI: 0.52-0.97; P = 0.03) in fracture fixation.

CONCLUSION

This meta-analysis shows that absorbable fixation systems used for fixation in maxillofacial surgery do not have adequate safety profiles. Subgroup indicated the safety of absorbable fixation systems was superior during fracture fixation. The absorbable fixation systems tend to have a similar favorable safety profile as titanium fixation during Le Fort I, bimaxillary operation and BSSRO.

Segmental stability of resorbable P(L/DL)LA-TMC osteosynthesis versus titanium miniplates in orthognatic surgery

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.

Patients' preoperative expectations and postoperative satisfaction of dysgnathic patients operated on with resorbable osteosyntheses

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.