Screw osteosynthesis compared with wire osteosynthesis in advancement genioplasty: a retrospective study of skeletal stability

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.

Long-term hard and soft tissue response following isolated genioplasty: a systematic review

PURPOSE

Genioplasty facilitates alteration of the chin position and contour which contributes to aesthetics and function. The response of the hard and soft tissues following genioplasty has not been assessed after a year or more of the surgery being performed. Hence, the aim of this systematic review was to assess the response of the hard and soft tissues occurring at least 1 year after the procedure.

MATERIAL AND METHODS

A literature search was conducted in the following electronic databases: PubMed, Ovid, LILACS, and Cochrane Library. Potential articles were identified wherein only studies with genioplasty performed as an isolated procedure and with data at least 12 months after the procedure were included.

RESULTS

Five studies were included in this systematic review. Two of the articles included were considered to be of good quality while three were considered to be of moderate quality using a modified Downs and Black tool. The ROBINS-I tool showed a moderate risk of bias for most domains. The study characteristics revealed varying degrees of relapse for the hard and soft tissues.

CONCLUSIONS

In the anteroposterior plane, the soft tissue relapsed more than the hard tissues 3 years post genioplasty. However, relapse in the vertical plane showed a wide variation for both the hard and soft tissues. In the anteroposterior plane, the hard tissue to soft tissue response 2 years or more following genioplasty ranged from 1:0.77 to 1:0.91 while in the vertical plane the hard tissue to soft tissue response ranged from 1:0.67 to 1:1.16.

Reoperative genioplasty: a 10-year retrospective study

PURPOSE

The purpose of this retrospective cohort study was to identify the causes of requiring reoperative genioplasty and determine the factors associated with reoperation.

METHODS

Medical records and radiographs of patients who underwent genioplasty were reviewed. The demographic data, characteristics of operation, and treatment outcomes were gathered to analyze the causes that required reoperation. Descriptive statistics and logistic regression analysis were computed to evaluate the study.

RESULTS

Of the 157 patients included, there were 12 patients (7.6%) who needed reoperation after genioplasty. Age ≤ 25 years significantly decreased the likelihood for the need for reoperative genioplasty compared with age > 35 years. However, the need for reoperative genioplasty was not directly associated with gender, simultaneous orthognathic operation, direction and amount of movement, method of fixation, or bone graft interposition. Fixation failure, esthetic problems, residual obstructive sleep apnea, and palpable step at the inferior border of the mandible were the causes that required a second operation by reposition and re-fixation with rigid fixation, recontouring, or reoperation by genioplasty.

CONCLUSION

Genioplasty procedure provided a predictive result. A reoperative rate was only 7.6% and younger age decreased the risk of reoperative genioplasty.

Long-term stability of isolated advancement genioplasty, and influence of associated risk factors: A systematic review

The aim of this review was to investigate the skeletal and soft tissue stability of isolated advancement genioplasty after more than 1 year, and to observe the influence of associated risk factors. A literature search was performed on PubMed, Web of Science, Embase, ScienceDirect, and Cochrane. Only studies with at least 10 patients who underwent an isolated advancement genioplasty, and with a follow-up period of at least 1 year, were included. Of the 2224 records initially identified, eight articles met the eligibility criteria. The mean age of the total study population was 23 years and ranged from 19.1 to 26.5 years in the individual studies. The average surgical advancement at pogonion was 8.2 mm and ranged from 6.2 to 11.7 mm in the individual studies. After 1 year, the horizontal hard tissue relapse at the level of pogonion varied from 0.1 to 2.1 mm. In two studies, this was reported as statistically significant. Regarding the soft tissue, the horizontal relapse varied from 0.3 to 2.9 mm, which was also considered statistically significant in two studies. Isolated advancement genioplasty was found to be a predictable and stable orthognathic procedure in the sagittal plane at both soft and hard tissue levels. The amount of relapse was not associated with the fixation method or with the amount of surgical advancement.

Stability of the chin after advancement genioplasty using absorbable plate and screws with template devices

PURPOSE

The purpose of this study was to compare the stability of the chin between absorbable plate and screws with a template device and titanium plate after advancement genioplasty in class II patients.

PATIENTS AND METHODS

The subjects consisted of 22 Japanese class II patients who underwent genioplasty advancement in combination with bi-maxillary surgery. After genioplasty horizontal osteotomy, the template plate and screws were fixed at the central region of the chin temporarily. Then, two absorbable bi-cortical screws (uncalcined and unsintered hydroxyapatite and poly-l-lactic acid: uHA/PLLA) were used and fixed bilaterally. After removal of the template plate and screws, one absorbable plate and screws were added to fix the segment in the advancement genioplasty (n = 14). The remaining 8 patients underwent genioplasty advancement surgery with the conventional titanium plate. For all patients, lateral cephalograms were obtained pre- and immediately after surgery and at 1 year after surgery. Change in the Pogonion (Pog) and Menton (Me) points and the corresponding soft tissue points (PogS and MeS) were evaluated.

RESULTS

Although there were no significant differences in the change from before to immediately after surgery between the absorbable and titanium groups, there were significant differences in the Pog (Y) (P = 0.0379) and PogS (Y) (P = 0.0379) from immediately after surgery to after 1 year between both groups.

CONCLUSION

This study shows that predicted advancement of the chin in the absorbable group could be achieved by using a template and screws, and likewise in the titanium group. However, this study suggested that vertical relapse to the inferior site or resorption at the antero-superior edge of the segment could occur in the absorbable group.

Musculoskeletal Changes as a Sequel to Advancement Genioplasty: A Long-Term Cephalometric Prospective Study

Aims

The aim of this study was to evaluate cephalometrically the stability of hard tissues and soft tissue changes of advancement genioplasty 2 years after surgery.

Methods

A prospective study was conducted which comprised of 25 patients, who underwent advancement genioplasty alone with no other orthognathic surgical procedures. Immediate pre-operative, 6 months postoperative, and 2 years postoperative lateral cephalograms were compiled and assessed.

Results

The mean surgical advancement planned was around 8 mm. Six months post-surgery, the relapse rate was 15% of the surgical advancement which was considerably reduced in the following 18 months to 7%. The ratio of soft tissue to bony advancement at pogonion was 0.9:1. There are significant alterations in the soft tissue profile in terms of decrease in the soft tissue thickness, facial convexity angle, deepened mentolabial sulcus and minimal increase in the lower lip height.

Conclusion

Advancement genioplasty was considered as a relatively stable procedure, if adequate muscular pedicle and internal rigid fixation were maintained. The present study was of 2 years, and we can expect further changes in the hard and soft tissues, which are clinically irrelevant.

Evaluation of ultrasonic and conventional surgical techniques for genioplasty combined with two different osteosynthesis plates: a cadaveric study

OBJECTIVES

The aim of this study was to compare genioplasties performed using traditional saw or piezosurgery combined with different osteosynthesis plates.

MATERIALS AND METHODS

Thirty-two genioplasties were first performed on fresh human cadavers using a saw or piezosurgery, followed by chin osteosynthesis with bending or pre-shaped plates. The time required for osteotomy and plate fixation was measured, and the suprahyoid pedicle was inspected.

RESULTS

The mean time required was 204 s (SD 43) with the saw and 52 s (SD 67) with piezosurgery. Osteosynthesis fixation time was 100 s (SD 31) for pre-shaped plates and 124 s (SD 24) for individual plates. Statistical differences were found between both osteotomy techniques (p < 0.001) and osteosynthesis plates (p = 0.025). Injuries of the suprahyoid muscle pedicle were found in 10/16 saw cases and 3/16 piezosurgery cases (p = 0.012).

CONCLUSIONS

Although piezosurgery is more time consuming compared with saw osteotomy, it is still adequate in time and allows a reduction of the suprahyoid pedicle injuries. Therefore, piezosurgery seems to be a viable alternative technique for genioplasty. From a clinical point of view, the time difference for osteosynthesis fixation has no significance.

CLINICAL RELEVANCE

The time taken for ultrasonic surgery is suitable for clinical use and leads additional to less damage to the suprahyoid pedicle.

A systematic review on soft-to-hard tissue ratios in orthognathic surgery part II: Chin procedures

PURPOSE

Precise soft-to-hard tissue ratios in orthofacial chin procedures are not well established. The aim of this study was to determine useful soft-to-hard tissue ratios for planning the magnitude of sliding genioplasty (chin osteotomy), osseous chin recontouring and alloplastic chin augmentation.

MATERIAL AND METHODS

A systematic review of English and non-English articles using PubMed central, ProQuest Dissertations and Theses, Science Citation Index, Elsevier Science Direct Complete, Highwire Press, Springer Standard Collection, SAGE premier 2011, DOAJ Directory of Open Access Journals, Sweetswise, Free E-Journals, Ovid Lippincott Williams & Wilkins total Access Collection, Wiley Online Library Journals, and Cochrane Plus databases from their onset until July 2014. Additional studies were identified by searching the references. Search terms included soft tissue, ratios, genioplasty, mentoplasty, chin, genial AND advancement, augmentation, setback, retrusion, impaction, reduction, vertical deficit, widening, narrowing, and expansion. Study selection criteria were as follows: only academic publications; human patients; no reviews; systematic reviews or meta-analyses; no cadavers; no syndromic patients; no pathology at the chin or mandible region; only articles of level of evidence from I to IV; number of patients must be cited in the articles; hard-to-soft tissue ratios must be cited in the articles or at least are able to be calculated with the quantitative data available in the article; if all patients of one article have had bilateral sagittal split osteotomy (BSSO) performed along with chin osteotomy, there should be an independent group evaluation of the data concerning to the chin; and no restriction regarding the size of the group. Independent extraction of articles by two authors using predefined data fields, including study quality indicators (level of evidence).

RESULTS

The search identified 22 articles. Eleven additional articles were found in their reference sections. Of these, two were evidence level IIIb, three were evidence level IIb, and the rest were evidence level IV. Three studies were prospective in nature. A high variability of soft-to-hard tissue ratios regarding genioplasty seemed to disappear if data were stratified according to confounding factors. With the available data, a soft-to-hard pogonion ratio of 0.9:1 and 0.55:1 could be used for chin advancement and chin setback surgery, respectively.

CONCLUSION

Advancement and extrusion movements of the chin segment show respectively a 0.9:1 of sPg:Pg horizontally and 0.95:1 of sMe:Me vertically. Setback and impaction movements show respectively a -0.52:1 of sPg:Pg horizontally and -0.43:1 of sMe:Me vertically. Prospective studies are needed that stratify by confounding factors such as type of osteotomy technique, magnitude of the movement, age, sex, race/ethnicity, and quantity and quality of the soft tissues. More specifically, studies are needed regarding soft-to-hard tissue changes after chin extrusion ("downgrafting"), intrusion ("impaction"), and widening and narrowing surgery.

Cost comparison of genioplasty: when indicated, wire osteosynthesis is more cost effective than plate and screw fixation

PURPOSE

This retrospective study was conducted to determine the difference in the cost of genioplasty according to the osseous fixation technique used.

PATIENTS AND METHODS

A retrospective study among orthognathic surgery patients treated over a 54-month period ending in June 30, 2011 was conducted. Immediately post surgery, panoramic and cephalometric radiographs of these patients were assessed to determine the presence of genioplasty procedure and the type of fixation used. The cost of the actual fixation used by the surgeons was compared with that which the cost would have been had the surgeons used the criteria described in the hypotheses, for plate and screws fixation when genioplasty is performed.

RESULTS

A review of 1,498 orthognathic surgery patients revealed that 473 of these patients underwent genioplasty. Out of 473 patients, 425 had genioplasty to either advance and-or superiorly reposition the chin. Of these, 230 had wire osteosynthesis and 243 had some form of rigid fixation. The unit cost of fixation for genioplasty when wire osteosynthesis is used is less than C$5.00. The mean unit cost estimate in our patient group when pre-bent plates are used was C$542.00. All 230 patients in whom wire osteosynthesis was used demonstrated stable fixation of the bony parts and no immediate postsurgical adjustment was required in any patient.

CONCLUSIONS

For patients requiring genioplasty to advance and-or superiorly reposition the chin, it is possible to use wire osteosynthesis to achieve accurate and stable fixation while reducing the fixation cost by more than C$500.00 per case. The surgeon should include cost considerations in the selection of treatment methods.

Comparison of rigid and semirigid fixation for advancement genioplasty

To compare the skeletal stability of rigid versus semirigid fixation for advancement genioplasty by the assessment of vertical and horizontal measurements pre-operatively and post-operatively on lateral cephalometric radiographs. The study comprised of patients who underwent standard advancement genioplasty by inferior osteotomy of the chin with broadest musculoperiosteal pedicle with either rigid fixation or wire fixation. The displacements of vertical and horizontal measurements resulting following surgery was derived by calculating the difference between preoperative, immediate post-operative and 1 year post-operatively on lateral cephalometric radiographs. Preoperative measurements were marked as T1, immediate post-operative as T2, 1 year follow up post-operative as T3. In the semirigid group a mean horizontal advancement of 5.97 mm was accompanied by a relapse of 1.623 mm during a period of minimum 1 year. The mean superior repositioning of menton was 0.7 mm. This was accompanied by a relapse of 0.325 mm during a period of 1 year. In the rigid group a mean horizontal advancement of 4.815 mm was accompanied by a relapse of 0.2 mm during a period of 1 year. The mean superior repositioning of menton was 0.975 mm. This was accompanied by a relapse of 0.1 mm during a period of 1 year. This study confirms the findings of several previous studies that contribute data specific towards the use of rigid fixation in advancement genioplasty. In our study we also observed that, in cases where large advancements are necessary, wire fixation may offer insufficient means of fixation particularly if the movement is complex and asymmetrical, in which case rigid fixation devices are more helpful.

Medpore versus osseous augmentation in genioplasty procedure: A comparison

BACKGROUND

Genioplasty deals with small area of craniofacial complex, namely, chin. Alloplastic chin implants and sliding genioplasty represent the two currently accepted methods of chin augmentation. Chin augmentation with medpore has become popular in the recent years.

MATERIAL AND METHODS

The study comprised 16 patients having retruded chin, out of whom 8 patients underwent sliding genioplasty while the other 8 underwent chin augmentation using medpore. The versatility and benefits of the two techniques are discussed.

RESULT AND CONCLUSION

All the patients achieved satisfactory results with no complication. Both the techniques can be used for mild to moderate retrogenia, while in the case of severe retrogenia, sliding genioplasty is recommended. Medpore is especially used for revision of chin shape. Medpore can give the same satisfactory result as osseous genioplasty in cases of mild to moderate horizontal chin deficiency. All the patients from both the groups showed significant improvement in facial profile and high degree of satisfaction resulting in improved self-esteem.

Long-term skeletal and soft-tissue responses after advancement genioplasty

INTRODUCTION

The objectives of this cephalometric study were to assess the skeletal stability of advancement genioplasty 3 years after surgery and to evaluate the predictability of soft-tissue changes.

METHODS

The subjects comprised 21 consecutive patients who had no additional orthognathic surgical procedures. Lateral cephalograms were taken at 5 times: immediately preoperative, immediately postoperative, 6 months postoperative, and 1 and 3 years postoperative.

RESULTS

Mean surgical advancement at pogonion was 8.4 mm. Three years after surgery, mean relapse at pogonion was 8% of the surgical advancement. Part of this change was most likely due to bone remodeling. No patient demonstrated a clinically significant postoperative change at pogonion. The soft tissue of the chin was found to follow bony movement in a ratio of 0.9:1. Great individual variability was observed. The mentolabial fold depth increased as a result of the treatment. Effects of advancement genioplasty on the lips were small.

CONCLUSIONS

A prediction ratio based on long-term skeletal changes is likely to generate an estimate that is more appropriate to present to the patient.

Bilateral Sagittal Split Osteotomy for Correction of Mandibular Prognathism: Long-Term Results

PURPOSE

To identify the long-term maxillomandibular changes after surgical correction of mandibular prognathism using bilateral sagittal split osteotomy (BSSO).

PATIENTS AND METHODS

Twenty patients who underwent BSSO to setback the mandible and had cephalometric radiographs taken preoperatively and postoperatively at 6 weeks, 1 year, and long-term follow-up (mean, 28 months). The cephalograms were traced and measured to determine the operative and postoperative changes. Correlation analyses were performed to see the relationship between the magnitude of setback and the amount of long-term postsurgical change at B point and pogonion.

RESULTS

The mean surgical setback was 8.2 mm at B point and 8.8 mm at pogonion. The mean long-term horizontal relapse was 2.3 mm (28.0%) at B point and 3.0 mm (34.1%) at pogonion. Out of 20 patients, 12 (60.0%) relapsed horizontally greater than 2 mm at B point and 13 (65.0%) at pogonion. The mean vertical surgical changes showed downward displacement of B point (2.3 mm) and pogonion (2.0 mm). The mean long-term vertical relapse was 1.6 mm (69.6%) at B point and 1.7 mm (85.0%) at pogonion.

CONCLUSION

There was no correlation between the magnitude of setback and the amount of relapse at B point and pogonion. However, there was significant correlation between the magnitude of vertical, downward surgical displacement and the amount of vertical relapse at B point and pogonion. The majority of the maxillofacial changes occurred within 1 year postoperatively.

A novel osteosynthesis plate design for routine corrective facial surgery

Plating systems for the osteosynthesis of facial osteotomies have different requirements to those used to treat facial fractures. The aim of fracture treatment is anatomical fragment reduction, functional/rigid immobilization, restoration of occlusion and aesthetics, and occasionally defect bridging. In corrective facial surgery however there is a need for intra-operative adjustments related to changes in occlusion and aesthetics, and defect bridging occurs frequently. Postoperatively, training elastics are used to control temporary neuromuscular imbalance. To accommodate these demands a new plating system is presented, based on five requisites: allowance of occlusal and aesthetic adjustment without hardware removal, plate dimensions that accommodate routine skeletal repositionings, reduced hardware volume compared with trauma plating systems, screws that fit the inter-dental spaces when tension banding, and capability for micro-screw fixation of bone grafts in the osteotomy site. The files of 1000 non-congenital facial deformity patients were analyzed. The sagittal, vertical and transverse movements were drawn and the bridging distances calculated. Slotted plates with double-armed interconnections were designed for maxillary, zygomatic-sandwich, chin and segmental osteotomies. A separate design was made for the sagittal split plate. A pilot study was performed using 20 patients. The system showed great versatility and adaptability, but a multicenter morbidity study is necessary, mainly to study postoperative stability.

Long-term hard and soft tissue relapse rate after genioplasty

PURPOSE

The purpose of this study was to assess hard and soft tissue stability 12 months after advancement genioplasty.

MATERIAL AND METHODS

This is a retrospective study of 20 patients who underwent either advancement genioplasty alone (n = 11) or in combination with bilateral sagittal split osteotomy for mandibular advancement (n = 9). Lateral cephalometric radiographs were traced and immediate postoperative changes and 12-month postoperative changes were defined. The relapse rate for the pogonion, the soft tissue pogonion, and the soft tissue B point (Bs) were evaluated. The results were compared for combined mandibular advancement plus genioplasty versus genioplasty alone. Relapse rates were also correlated with the amount of advancement. All patients were treated with rigid internal fixation.

RESULTS

After 12 months, the pogonion, the soft tissue pogonion, and the soft tissue B point had a mean relapse rate of -0.38 mm, -1.2 mm, and -1.5 mm (negative value indicates a relapse, and a positive value indicates prolapse), respectively, which was not significant at probability values of.45,.069, and.054, respectively. Relapse was not statistically related to the amount of advancement. There was no significant difference between the relapse rate for genioplasty alone versus combined bilateral sagittal split osteotomy and genioplasty, even with different amounts of advancement.

CONCLUSIONS

Advancement genioplasty is an important and reliable technique for the esthetic treatment of the lower facial skeleton. The results indicate that there is no significant relapse after genioplasty and bilateral sagittal split osteotomy or genioplasty alone after 12 months when rigid internal fixation is used. The changes were minimal and hard to detect clinically. Genioplasty, with or without mandibular advancement, is a stable surgical procedure when used in conjunction with rigid internal fixation.

Osseous remodeling after inferior border osteotomy for chin augmentation: an indication for early surgery

PURPOSE

This study investigated the relationship of age at surgery and type of fixation to the pattern and extent of bone remodeling associated with inferior border osteotomy for chin augmentation.

PATIENTS AND METHODS

Four groups of patients with similar chin advancement were established by age at the time of surgery: younger than 15, 15 to 19, 20 to 24, and older than 39 years. Cephalometric radiographs for immediate preoperative, immediate postoperative, and at least 9 months postoperative times were traced, digitized, and superimposed.

RESULTS

The pattern of osseous remodeling was similar for all age-groups. This consisted of resorption of the superior-buccal aspect of the distal segment, bone apposition on the buccal surface of the proximal segment, and modest resorption at pogonion (mean change, 1 mm or less). There was no significant difference in stability of the chin advancement between wire and rigid (screw) fixation. There was a marked difference in the symphysis thickness regeneration of the youngest group (92% of the original symphysis thickness) compared with the rest of the groups (< or =66%, P < .001).

CONCLUSIONS

Minimal remodeling at pogonion occurs in all age-groups with both wire and rigid fixation. Regeneration of symphysis thickness is much more complete in patients younger than 15 years at the time of surgery. This is potentially important for early treatment of severe chin deficiency, because it permits additional advancement of the chin later in life, if necessary.