Risk Factors for Neurosensory Disturbance After Bilateral Sagittal Split Osteotomy Based on Position of Mandibular Canal and Morphology of Mandibular Angle

doi:10.1016/j.joms.2011.01.040

Journal of Oral and Maxillofacial Surgery

Volume 70, Issue 2, February 2012, Pages 401-406

https://doi.org/10.1016/j.joms.2011.01.040 Get rights and content

Purpose

The aim of the present study was to evaluate the potential morphologic risk factors for postoperative neurosensory disturbance (NSD) after bilateral sagittal split osteotomy.

Patients and Methods

The study subjects were 30 skeletal Class III patients (9 males and 21 females), with a mean age of 22.0 years (range, 16-39 years). All patients underwent bilateral sagittal split osteotomy for setback to correct mandibular prognathism. The bone marrow space between the outer mandibular canal and the lateral cortex of the ramus was measured on transaxial computed tomography images, and the length at the mandibular angle between the retromolar and gonion was measured on the lateral cephalograms. The NSD was tested bilaterally using discrimination to touch with the sharp head of a mechanical probe. Each patient was evaluated at 1, 3, and 6 months postoperatively.

Results

The median bone marrow space was 1.96 mm (range, 0-4.5 mm), and median length of the mandibular angle was 30.93 mm (range, 23-37 mm). Neurosensory disturbance was present on 15 sides (25.0%) at 1 month postoperatively, 9 sides (15.0%) at 3 months postoperatively, and 7 sides (11.7%) at 6 months postoperatively. The difference in the incidence of NSD with a small bone marrow space and a long mandibular angle from that with a large bone marrow space and short mandibular angle was highly statistically significant (P = .006 and P < .01, respectively).

Conclusions

The frequency of NSD after bilateral sagittal split osteotomy in Class III cases was dependent not only on the position of mandibular canal, but also on the length of the mandibular angle. A lateral course of the mandibular canal and a long mandibular angle appeared to result in a high risk of injury to the inferior alveolar nerve, resulting in NSD owing to a compromised splitting procedure.

Section snippets

Patients and Methods

The institutional ethics committee of Kyushu Dental College approved the present retrospective study. The study subjects were 30 skeletal Class III patients (9 males and 21 females), with a mean age of 22.0 years (range, 16-39 years). All patients underwent BSSO for mandibular setback at the Division of Oral and Maxillofacial Reconstructive Surgery at Kyushu Dental College (Kitakyushu, Japan) and had the same sequence of preoperative radiographic and clinical examinations, treatment planning,

Results

The median bone marrow space was 1.96 mm (range, 0-4.5 mm), and the median length of the mandibular angle was 30.9 mm (range, 23-37 mm).

Neurosensory disturbance was seen on 15 sides (25.0%) at 1 month postoperatively, 9 sides (15.0%) at 3 months postoperatively, and 7 sides (11.7%) at 6 months postoperatively (Fig 3). The frequency of NSD decreased with an increasing bone marrow space. Neurosensory disturbance at 1 month postoperatively was observed in 8 (57.1%) of 14 in group I, 5 (25.0%) of

Discussion

Neurosensory disturbance remains 1 of the major complications of BSSO. Previous studies have revealed that the risk factors include neurosensory damage, compression or decompression injuries during medial periosteal dissection, fixation methods, postoperative swelling or bleeding, patient age, the osteotomy line, and the direction of mandibular movement.5, 8, 9, 10 Neurosensory disturbance arising from the splitting procedure can directly interfere with function; thus, it is important to

References (20)

R.B. Macintosh
Experience with the sagittal split osteotomy of mandibular ramus: A 13 year review
J Oral Maxillofac Surg
(1981)
A. Al-Bishri et al.
Neurosensory disturbance after sagittal split and intraoral vertical osteotomy: As reported in questionnaires and patients' records
Int J Oral Maxillofac Surg
(2005)
L. Ylikontiola et al.
Factors affecting neurosensory disturbance after mandibular bilateral sagittal split osteotomy
J Oral Maxillofac Surg
(2000)
F. Tamas
Position of the mandibular canal
Int J Oral Maxillofac Surg
(1987)
R. Yamamoto et al.
Relationship of the mandibular canal to the lateral cortex of the mandibular ramus as a factor in the development of neurosensory disturbance after bilateral sagittal split osteotomy
J Oral Maxillofac Surg
(2002)
Y. Tsuji et al.
Computed tomographic analysis of the position and course of the mandibular canal: Relevance to the sagittal split ramus osteotomy
Int J Oral Maxillofac Surg
(2005)
R.R. Lemke et al.
Neurosensory differences after wire and rigid fixation in patients with mandibular advancement
J Oral Maxillofac Surg
(2000)
K. Nakagawa et al.
Trigemial nerve hypesthesia after sagittal split osteotomy in setback cases: Correlation of postoperative computed tomography and long-term trigeminal somatosensory evoked potentials
J Oral Maxillofac Surg
(2003)
D. Hallikainen et al.
Cross-sectional tomography in evaluation of patients undergoing sagittal split osteotomy
J Oral Maxillofac Surg
(1992)
T. Teerijoki-Oksa et al.
Recovery of nerve injury after mandibular sagittal split osteotomy: Diagnostic value of clinical and electrophysiologic tests in the follow-up
Int J Oral Maxillofac Surg
(2004)

There are more references available in the full text version of this article.

Cited by (60)

Risk factors of neurosensory disturbances at 1 year postoperatively after bilateral sagittal split osteotomy
2022, Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
To investigate morphologic and surgical risk factors causing neurosensory disturbances (NSDs) after bilateral sagittal split osteotomy (BSSO).
A total of 237 patients (with 474 sides) who underwent BSSO were followed up for 1 year. Parameters examined included age, sex, asymmetry, mandibular movement direction, mandible cutting devices, split type, intraoperative exposure of the inferior alveolar nerve (IAN), contact between the IAN and screw, distance between mandibular canal and inner surface of the cortical bone (distance A), distance from lateral osteotomy to mental foramen (distance B), and NSD at 1 year postoperatively.
NSD was observed in 62 (13.1%) sides of 51 patients. Exploratory factor analysis determined 4 factors (factor 1: distance A; factor 2: direction of mandibular movement; factor 3: distance B and cutting devices; factor 4: IAN exposure). Logistic regression analysis was performed using the above factors and age, sex, and asymmetry, making a total of 7 variables. Age, factor 1, and factor 4 were significant predictors of NSD.
Advanced age, close distance between mandibular canal and inner surface of the cortical bone, and IAN intraoperative exposure are risk factors for NSD 1 year postoperatively. Cases at high risk for NSD must be treated with great care.
Bone marrow space volume of the mandible influencing intraoperative blood loss in bilateral sagittal split osteotomy: A pilot Study
2022, Journal of Stomatology, Oral and Maxillofacial Surgery
Citation Excerpt :
BSSO involves separating buccal cortical bone from inner cancellous bone, exposing the bone marrow space of the mandible. A previous report mentioned that a smaller bone marrow space was associated with a greater risk of neurosensory disturbance after BSSO [6]. However, whether the bone marrow space volume of the mandible affects blood loss during BSSO remains unclear.
The aim of this study was to investigate whether the bone marrow space volume of the mandible affects blood loss during bilateral sagittal split osteotomy (BSSO).
Sixteen patients who underwent BSSO in our hospital were included in this study. Bone marrow space volume of the mandible was measured by analyzing images from computed tomography. Blood loss during BSSO was measured by weighing gauze, measuring suctioned blood, and adjusting for the volume of irrigation solution used during BSSO.
Mean blood loss during BSSO for the 16 patients was 200.5 ml, and patients were divided into: Group I, with less than mean blood loss; and Group II, with greater than mean blood loss. Total bone marrow space volume was significantly greater in Group II (12,450.7 ± 2644.3 mm³) than in Group I (9130.3 ± 3005.8 mm³; P<0.05).
A correlation between bone marrow space volume and blood loss during BSSO was suggested, and these results are beneficial for surgeons planning and preparing the orthognathic surgery.
Radiologic Risk Factors for Persistent Mandibular Nerve Neurosensory Disturbance Following Sagittal Split Osteotomy
2022, Journal of Oral and Maxillofacial Surgery
Neurosensory disturbance (NSD) occurring in the lower lips and chin is a major postoperative complication related to bilateral sagittal split osteotomy (SSO). The purpose of this study is to identify preoperative radiographic findings following SSO procedure associated with persistent NSD.
This retrospective cohort study analyzed data for consecutive patients who underwent SSO. Primary predictor variables, including ramus width, mandibular body height, mandibular angle length, gonial angle, distance from mental foramen to distal aspect of mandibular second molar (MFD), and measurement of bone marrow space (BMS), were examined in a series of radiographic images. The primary outcome variable was NSD. Patients with NSD were divided into 2 groups based on findings obtained 1 year postoperatively: persistent, for those with NSD remaining after 1 year, and transient, when NSD occurred for less than 1 year. Covariates included sex and age. Comparisons were analyzed by use of Mann-Whitney U test or χ² test. Multivariate analysis was performed using step-wise logistic regression to determine significant factors related to persistent NSD. A P value .005 or less was considered statistically significant.
Of the 349 sides investigated, the persistent NSD group consisted of 59 sides (16.9%), while the transient NSD group consisted of 290 sides (83.1%). The occurrence of persistent NSD was correlated with age (P < .05), MFD (P < .001), mandibular body height (P < .05), and BMS (P < .001). Multivariate logistic analysis also showed a significant association of MFD (P < .001) and BMS (P < .001).
Preoperative MFD and BMS are radiographic findings that are associated with an increased risk for persistent NSD following SSO procedure.
Position of the mandibular canal before and after bilateral sagittal split ramus osteotomy: a cone beam computed tomographic study
2022, British Journal of Oral and Maxillofacial Surgery
The aim of this study was to evaluate the position of the mandibular canal (MC) before and after bilateral sagittal split ramus osteotomy (BSSRO) using cone-beam computed tomography (CT), and to compare the position of the MC in Class II and Class III patients in the preoperative period. Patients were divided into two groups: Class II (n = 38) and Class III (n = 41). Measurements of the superior, inferior, buccal, and lingual distances of the MC in relation to the cortical bone were taken at three levels in the proximal segment of the mandible. Results were analysed using the Kruskal–Wallis test (p < 0.05). In the Class II group the superior distance of the MC at levels 2 and 3, and the inferior distance at level 3 significantly decreased after BSSRO. In the Class III group, no significant differences were found at any level, and the inferior distances at all levels were smaller preoperatively than those in the Class II group. In the Class II group the position of the MC altered in relation to superior and inferior cortical bone after BSSRO. However, the position of the MC remained stable in the Class III group. Our results also suggest a deeper cut in inferior cortical bone in Class III patients.
POST-SURGICAL NEUROSENSORY DYSFUNCTION OF INFERIOR ALVEOLAR NERVE IN BILATERAL SAGITTAL SPILT OSTEOTOMY OF THE MANDIBLE USING SAW VERSUS PIEZOTOME: A SYSTEMATIC REVIEW AND META-ANALYSIS
2022, Journal of Evidence-Based Dental Practice
Citation Excerpt :
The incidence of transection is reported in 2% to 3.5% of the operated patients.3 IAN NSD has been reported to occur in 25% to 98% of the patients immediately or up to one month after BSSO4-7 and in 11.7% to 85% of the injured patients, 6 months post-operatively.3,5-8 Long-term neurologic deficit occurs in 10% to 30% of the affected patients, whether annoyed or not.3
Purpose: The purpose of this systematic review was to compare neuro-sensory dysfunction incidence between saw and piezotomes in patients requiring bilateral sagittal split osteotomy.
Methods: Searches were performed electronically in 4 databases (PubMed, LILACS, Cochrane Library, and grey literature) up to September 2020 and manually to identify studies addressing the subject. Randomized and non-randomized clinical trials were included.
Results: Six studies met the eligibility criteria with a total number of 284 participants. The risk of bias assessment for randomized clinical trials was high, and for non-randomized clinical trials was critical and serious. Regarding inferior alveolar neuro-sensory dysfunction, the meta-analysis showed no significant difference between saw and piezotome 1 week [RR = 0.99, 95% CI (0.90, 1.08) P = 0.79], and 3 months [RR = 0.39, 95% CI (0.09, 1.75) P = 0.22], post-operatively.
Conclusions: For patients requiring bilateral sagittal split osteotomy, piezotomes seem to offer no advantage over conventional saws regarding the incidence of neurosensory disturbance. Follow-up periods longer than 3 months may reveal faster physiologic regain of sensations. They seem to be safer than conventional saws regarding blood loss. However, proper training for using the device is mandatory, while considering the longer operating time required. Further RCTs are still recommended to improve the level of evidence.
Computed tomography assessment of mandibular morphologic changes and the inferior mandibular border defect after sagittal split ramus osteotomy
2021, Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
This study aimed to assess mandibular morphologic changes to the condyle, ramus, mandibular body, and inferior mandibular border defect after sagittal split ramus osteotomy in class II and III patients.
The relationships among the condyle, ramus, and mandibular body measured by computed tomography preoperatively and postoperatively were assessed and factors related to the reduction of the condylar square and mandibular inferior border defect were examined.
Patients included 72 female patients with jaw deformity (36 skeletal class II cases, 36 skeletal class III cases). Postoperative reduction of the condylar square was significantly correlated with preoperative condylar height in patients with class II (P = .0297) vs preoperative condylar height and preoperative mandibular height in patients with class III (P < .0001). A mandibular inferior border defect was found in 18 of 72 class II sides (25.0%) and was significantly related to the position of the osteotomy line and attachment side of the inferior border cortex (P < .0001).
This study's findings suggest that the postoperative reduction of the condyle could be associated with preoperative condylar height. However, the mandibular inferior border defect in class II advancement surgery could be independently associated with technical factors in sagittal split ramus osteotomy.

View all citing articles on Scopus

View full text

Craniomaxillofacial deformities/cosmetic surgeryRisk Factors for Neurosensory Disturbance After Bilateral Sagittal Split Osteotomy Based on Position of Mandibular Canal and Morphology of Mandibular Angle

Purpose

Patients and Methods

Results

Conclusions

Section snippets

Patients and Methods

Results

Discussion

J Oral Maxillofac Surg

Int J Oral Maxillofac Surg

J Oral Maxillofac Surg

Int J Oral Maxillofac Surg

J Oral Maxillofac Surg

Int J Oral Maxillofac Surg

J Oral Maxillofac Surg

J Oral Maxillofac Surg

J Oral Maxillofac Surg

Int J Oral Maxillofac Surg

Craniomaxillofacial deformities/cosmetic surgery
Risk Factors for Neurosensory Disturbance After Bilateral Sagittal Split Osteotomy Based on Position of Mandibular Canal and Morphology of Mandibular Angle