Risk factors for a bad split during sagittal split osteotomy

One of the operative complications during sagittal split osteotomy (SSO) in orthognatic surgery is a bad split, meaning an undesired fracture of the mandible during osteotomy. The aim of this study was to find out if there is a relation between the occurrence of bad splits during SSO and the presence of third molars, the patient's age, or the surgeon's experience. Clinical notes of 110 consecutive patients who had had a total of 220 SSOs using the Obwegeser/Dal Pont technique were evaluated and divided into three groups: 1 missing third molar (n=168); 2 retained or impacted third molar that was removed during the SSO (n=23); and 3 third molar left in place during SSO (n=29). There were a total of 12 (6%) bad splits. 9 (5%) in group 1, two (9%) in group 2, and one (3%) in group 3. There were no significant differences between groups 1-3, in particular the surgeon's qualification had no influence on the incidence. Older patients seemed more at risk of a bad split than younger ones.     

Risk factors and prevention of bad splits during sagittal split osteotomy

Purpose

One of the operative complications of the sagittal split osteotomy of the mandible is a bad split, which describes an unfavorable or irregular fracture of the mandible in the course of the osteotomy. The purpose of this study is to identify previous studies which reported incidences of bad split occurrence during sagittal split osteotomy and to discuss its mechanisms and risk factors, based on a literature review, in order to minimize their occurrence. A few illustrative cases are also presented.

Methods

An electronic search was undertaken in January 2011. The titles and abstracts from these results (n?=?363) were read for identifying studies which reported incidences of bad split occurrence during sagittal split osteotomy procedures.

Results

Twenty-one studies were identified and assessed. The incidence of bad splits from these studies varied between 0.21% and 22.72%. The buccal plate of the proximal segment and the posterior aspect of the distal segment were the most affected areas.

Discussion

The surgical patient should be evaluated according to age and the presence of unerupted/impacted third molars. Prevention is focused on adequate osteotomy design, eliminating sharp angle where abnormal stress occurs on bony segments, completion of adequate cuts into the retrolingular depression and through the inferior border, and careful separation of the segments. The SSO is an extremely technical and sensitive procedure, and careful attention will probably prevent most unfavorable splits. If a fracture occurs, the fractured segments should be incorporated into the fixation scheme if possible. The occurrence of bad splits cannot always be avoided. When adequately treated the chances of functional success are good.     

Complications after mandibular sagittal split osteotomy

Sagittal split osteotomy has been performed routinely for correction of mandibular prognathism, retrognathia, mild open bite, and asymmetry. Intraoperative and early or late postoperative complications were evaluated in 258 patients operated on by this technique. With meticulous performance of the operation and long-term maxillomandibular fixation, complications can be negligible, and relapse, the most problematic postoperative issue, can be significantly reduced.     

下颌升支矢状劈开术并发下牙槽神经损伤的研究进展

下牙槽神经(inferior alveolar nerve,IAN)损伤是下颌正颌手术后最为常见的并发症,也是患者和术者共同关心的问题。其发生率报道不一。有关其发生的影响因素主要包括解剖因素与手术因素。下颌升支矢状劈开术作为最常用的下颌正颌外科术式,术中操作技巧与IAN损伤密切相关。IAN损伤的主要症状是患侧下唇、颏部、牙龈的感觉缺失,少数患者出现持续疼痛,触痛以及咬合疼痛或不适。该文对正颌术后IAN损伤的发病特点、影响发病的相关因素、临床表现及治疗方法等作一综述。     

Traumatic neuroma following sagittal split mandibular osteotomy

A 23-year-old female patient had a sagittal split mandibular osteotomy performed to correct prognathism. Two years after surgery she developed pain in the distribution of the right inferior dental and mental nerves. The area was investigated surgically and a traumatic neuroma was excised.     

An evaluation of clinical and electrophysiologic tests in nerve injury diagnosis after mandibular sagittal split osteotomy

The yield of clinical sensory tests and electrophysiologic tests in the diagnostics of inferior alveolar nerve (IAN) damage after bilateral sagittal split osteotomy (BSSO) was studied. The diagnostic value of these tests was evaluated by comparing the test results to the degree of nerve damage at the end of the operation as documented by means of the intraoperative nerve conduction recording of the IAN. Twenty patients undergoing BSSO were analysed preoperatively and 2 weeks postoperatively. The frequency of the IAN disturbance ranged from 10% to 94% depending on the test method and the test site used. Of the clinical sensory tests, the touch detection threshold (TD) test was the most sensitive and clinically useful test. It also correlated best with the electrophysiologically verified intraoperative nerve damage (R = -0.603, P = 0.017 on the right, R = -0.626, P = 0.01 on the left). The blink reflex and quantitative cold detection threshold tests were almost as often abnormal as the TD-test, but nerve conduction study (NCS) was the most sensitive (88%) of all clinical and electrophysiologic tests. The frequency of abnormal findings in the electrophysiologic tests indicating IAN injury, 75% on the right side and 90% on the left side, corresponded exactly with the figures of subjective sensory alteration. Almost all electrophysiologic tests showed obvious associations with the objectively verified IAN damage. All tests, except the NCS, showed only moderate sensitivity. Specificity of the tests was generally high, the only exceptions being the TD test and the NCS. To increase the diagnostic accuracy of the testing and to detect different types of damage in different nerve fibre populations, a combination of different sensory and electrophysiologic tests is recommended.     

Surgical emphysema complicating mandibular sagittal split osteotomy

A case of surgical emphysema is reported. occurring after a mandibular sagittal split osteotomy. The aetiology and possible complications of this condition are discussed.     

Modification of the mandibular ramus sagittal split osteotomy

The sagittal split osteotomy of the mandibular ramus is a common procedure used in the correction of mandibular deformities. Modifications of the procedure will be presented for advancement and setback of the mandible. Major advantages of this technique include controlled splitting of the segments and predictable positional control of the proximal segment. The advantages and disadvantages of rigid skeletal stabilization are discussed, as well as application to the modified mandibular ramus sagittal split osteotomy.     

Facial nerve injury as a complication of sagittal split ramus osteotomy

A little-considered potential complication to the sagittal ramus split has been called to the attention of surgeons. The abnormal EMG recordings, coupled with the pattern of recovery, suggests Wallerian degeneration as the pathologic process in this patient.     

Original sagittal split osteotomy revisited for mandibular distraction

Introduction: A malformed mandible and an abnormally positioned mandibular foramen make it difficult to plan an ideal osteotomy line for mandibular distraction. In addition, there have been reports of such complications as nonunion, damage and stretch injury of the inferior alveolar nerve and tooth germ damage when conventional osteotomy or corticotomy are used for mandibular distraction. The authors utilized the original sagittal split ramus osteotomy for mandibular distraction. Patients and Methods: Five patients (three unilateral hemifacial microsomia, one bilateral hemifacial microsomia, and one mandibular retrusion) were included in this study of distraction osteogenesis using the sagittal split ramus osteotomy. Extraoral distraction devices were applied to the first four patients. An intraoral device with mono-cortical screw fixation was used for the fifth patient. Result: In all five cases, the results of the distraction were satisfactory. Complications (as listed) of conventional osteotomy when used for distraction were avoided. Satisfactory results were achieved and these were also well maintained postoperatively (mean follow up: 36 months). Conclusion: The authors believe that sagittal osteotomy for mandibular distraction osteogenesis makes it possible, to avoid injury to the inferior alveolar nerve during operation and stretching injury during distraction and to prevent tooth germ injury. It is also possible to diversify the osteotomy line for various force vectors to enlarge the bony contact surface area. Therefore, we suggest that sagittal split ramus osteotomy should be used as a preferred modification of osteotomy for mandibular distraction. Copyright 2001 European Association for Cranio-Maxillofacial Surgery.     

Risk factors contributing to symptomatic plate removal following sagittal split osteotomy

The records of 80 consecutive patients (160 plates) undergoing orthognathic surgery over a 2-year period were analysed to assess the percentage of plate removal from the mandible following sagittal split osteotomy. Factors considered in the study included age, sex, duration of operation, antibiotic prophylaxis regimen, general medical condition, smoking habits, mandibular moves, extraction of 3rd molars at time of surgery and the favourability of the mandibular splits. Infection was the sole reason for plate removal in this study. A removal rate of 15.6% was noted. Age and duration of operation were the only 2 statistically significant factors to affect plate removal whilst some of the other factors showed increased odds ratios but were not statistically significant.     

Original sagittal split osteotomy revisited for mandibular distraction.

INTRODUCTION: A malformed mandible and an abnormally positioned mandibular foramen make it difficult to plan an ideal osteotomy line for mandibular distraction. In addition, there have been reports of such complications as nonunion, damage and stretch injury of the inferior alveolar nerve and tooth germ damage when conventional osteotomy or corticotomy are used for mandibular distraction. The authors utilized the original sagittal split ramus osteotomy for mandibular distraction. PATIENTS AND METHODS: Five patients (three unilateral hemifacial microsomia, one bilateral hemifacial microsomia, and one mandibular retrusion) were included in this study of distraction osteogenesis using the sagittal split ramus osteotomy. Extraoral distraction devices were applied to the first four patients. An intraoral device with mono-cortical screw fixation was used for the fifth patient. RESULT: In all five cases, the results of the distraction were satisfactory. Complications (as listed) of conventional osteotomy when used for distraction were avoided. Satisfactory results were achieved and these were also well maintained postoperatively (mean follow up: 36 months). CONCLUSION: The authors believe that sagittal osteotomy for mandibular distraction osteogenesis makes it possible, to avoid injury to the inferior alveolar nerve during operation and stretching injury during distraction and to prevent tooth germ injury. It is also possible to diversify the osteotomy line for various force vectors to enlarge the bony contact surface area. Therefore, we suggest that sagittal split ramus osteotomy should be used as a preferred modification of osteotomy for mandibular distraction.     

Long-term stability of mandibular advancement with bilateral sagittal split osteotomy

Introduction

Aim of this study was 1) to evaluate long-term dental/skeletal stability in patients with mandibular retrognathia corrected by BSSO, and 2) to examine factors associated with relapse.

双侧升支矢状劈开截骨后退下颌术后骨的稳定性的研究

目的：探讨双侧升支矢状劈开截骨术（BSSRO）后退下颌骨以钢丝结扎固定两骨段加颌间固定术后骨的稳定性，了解导致复发的有关因素。方法：双侧下颌升支矢状劈开截骨手术后退下颌的患者14例，于手术前1周，手术后1周，术后6个月分别拍摄定位头颅侧位片及许勒位X线片，用于测量下颌移动的距离及确定下颌骨髁状突的位置。结果：双侧下颌升支矢状劈开截骨后退术后，6个月的复发率为27.2%，多元逐步回归分析示下颌后退的距离与复发相关。结论：BSSRO后退下颌骨的距离越大，术后下颌骨向前移位的可能越大。     

Technical modification of the sagittal split mandibular ramus osteotomy.

The sagittal split mandibular ramus osteotomy is a versatile surgical option for the correction of mandibular prognathism, retrognathism, and asymmetry. At the same time, it enables the use of internal rigid fixation. However, surgical complications including injury to the inferior dental neurovascular bundle and unfavorable fracture can occur. A technical modification and a concept in instrumentation is suggested with the view of minimizing such complications.