Gertjan Mensink

Neurosensory disturbances one year after bilateral sagittal split osteotomy of the mandibula performed with separators: A multi-centre prospective study

Bilateral sagittal split osteotomy (BSSO) is an effective and commonly used treatment to correct mandibular hypo- and hyperplasia. Hypoesthesia of the inferior alveolar nerve (IAN) is a common complication of this surgical procedure. This prospective multi-centre study aimed to determine the incidence of neurosensory disturbances of the IAN after BSSO procedures performed without the use of chisels. Our study group comprised 158 patients, with a follow-up period of 1 year, who underwent BSSO (with or without Le Fort I) that incorporated the use of sagittal split separators and splitters but no chisels. The percentage of BSSO split procedures that resulted in IAN damage was 5.1%. The percentage of patients (without genioplasty) who experienced IAN damage was 8.9%. The concomitant genioplasty in combination with BSSO was significantly associated with hypoesthesia. Peri-operative removal of the wisdom tooth or a Le Fort I procedure did not influence post-operative hypoesthesia. We believe that the use of splitting forceps and elevators without chisels leads to a lower incidence of persistent post-operative hypoesthesia 1 year after BSSO of the mandible, without increasing the risk of a bad split.

Bad split during bilateral sagittal split osteotomy of the mandible with separators: a retrospective study of 427 patients

An unfavourable fracture, known as a bad split, is a common operative complication in bilateral sagittal split osteotomy (BSSO). The reported incidence ranges from 0.5 to 5.5%/site. Since 1994 we have used sagittal splitters and separators instead of chisels for BSSO in our clinic in an attempt to prevent postoperative hypoaesthesia. Theoretically an increased percentage of bad splits could be expected with this technique. In this retrospective study we aimed to find out the incidence of bad splits associated with BSSO done with splitters and separators. We also assessed the risk factors for bad splits. The study group comprised 427 consecutive patients among whom the incidence of bad splits was 2.0%/site, which is well within the reported range. The only predictive factor for a bad split was the removal of third molars at the same time as BSSO. There was no significant association between bad splits and age, sex, class of occlusion, or the experience of the surgeon. We think that doing a BSSO with splitters and separators instead of chisels does not increase the risk of a bad split, and is therefore safe with predictable results.

Presence of mandibular third molars during bilateral sagittal split osteotomy increases the possibility of bad split but not the risk of other post-operative complications

Timing of third molar removal in relation to bilateral sagittal split osteotomy (BSSO) is controversial, especially with regard to post-operative complications. We investigated the influence of mandibular third molar presence on complications after BSSO with sagittal splitters and separators, by a retrospective record review of 251 patients (502 surgical sites). Mandibular third molars were present during surgery at 169 sites and removed at least 6 months preoperatively in 333 sites. Bad splits occurred at 3.0 % (5/169) and 1.5% (5/333) of the respective sites. Presence of mandibular third molars significantly increased the risk of bad splits (OR 1.08, CI 1.02-1.13, p < 0.01). The mean incidences of permanent neurosensory disturbances, post-operative infection, and symptomatic removal of the osteosynthesis material were 5.4% (OR, 0.89; 95% CI, 0.79-1.00; p = 0.06), 8.2% (OR, 1.09; 95% CI, 0.99-1.20; p = 0.63), and 3.4% (OR, 0.97; 95% CI, .92-1.03; p = 0.35) per site, respectively, without a significant influence of mandibular third molar status. In conclusion, the presence of mandibular third molars during surgery increases the possibility of bad split but does not affect the risk of other complications. Therefore, third molars can be removed concomitantly with BSSO using sagittal splitters and separators.

Endoscopically assisted reduction of anterior table frontal sinus fractures

AIMS To present a retrospective series of six patients with endoscopically assisted reduction of anterior table frontal sinus fractures. MATERIALS AND METHODS The patients with isolated anterior table fractures were treated between April 2005 and June 2006 in the Leiden University Medical Centre. In two of the six patients the procedure was performed under local anaesthesia. The endoscope was introduced via existing lacerations, an incision in a natural skin crease or just above the hairline. The fracture was reduced and if necessary fixed. RESULTS In all patients restoration of the cosmetic deformity was achieved clinically. CONCLUSION The use of endoscopes makes minimally invasive reduction of outer table fractures of the frontal sinus possible, even under local anaesthesia.

Autotransplantation of premolars.

Autotransplantation is a reliable treatment option for the replacement of missing teeth; however, there is a wide variation in reported survival rates. The purpose of this study was to evaluate the success and survival rate of premolar autotransplantation and to underline the importance of autotransplantation in the treatment of missing teeth. We present the treatment and follow-up of 63 premolar autotransplants in 44 patients. After transplantation under local anaesthesia, radiological and clinical follow-up showed a survival rate of 100%, ie all premolars were still functional. We conclude that autotransplantation of premolars is a reliable treatment method especially for agenesis. It is not difficult to perform and is aesthetically superior and more cost-effective than other treatments, especially when orthodontic alignment is necessary.

Skeletal stability after mandibular advancement in bilateral sagittal split osteotomies during adolescence.

Bilateral sagittal split osteotomy (BSSO) is the most frequently performed surgery for correcting mandibular retrognathia. Few studies have reported the use of BSSO in young patients, as growth may cause relapse. The aim of the present study was to determine the amount of relapse after performing BSSO in patients aged less than 18 years. Patients who had a mandibular advancement by BSSO surgery between January 2003 and June 2008 were evaluated. Eighteen patients were treated before the age of 18 years and compared with patients treated at 20-24 years of age. Cephalometric radiographs were used to determine the amount of relapse. For patients aged less than 18 years, the mean horizontal relapse after 1 year was 0.5 mm, (10.9% of perioperative advancement). For patients aged 20-24 years, the mean relapse was 0.9 mm, (16.4% of perioperative advancement). There were no significant differences between the age groups (p > 0.05). In conclusion, the BSSO procedure is a relatively stable procedure, even during adolescence.

Angled Osteotomy Design Aimed to Influence the Lingual Fracture Line in Bilateral Sagittal Split Osteotomy: A Human Cadaveric Study

PURPOSE The traditional osteotomy design in the bilateral sagittal split osteotomy includes a horizontal lingual bone cut, a connecting sagittal bone cut, and a vertical buccal bone cut perpendicular to the inferior mandibular cortex. The buccal bone cut extends as an inferior border cut into the lingual cortex. This study investigated a modified osteotomy design including an angled oblique buccal bone cut that extended as a posteriorly aimed inferior border cut near the masseteric tuberosity. MATERIALS AND METHODS The authors implemented a randomized controlled study. The study sample was comprised of 28 cadaveric dentulous mandibles. The primary outcome variable was the pattern of lingual fracture induced using the conventional (n = 14) and modified (n = 14) osteotomy designs. The secondary outcome variables included the incidence of bad splits and the status of the inferior alveolar nerve (IAN). Descriptive and bivariate statistics were computed. RESULTS The angled osteotomy design resulted in a significantly larger number of the lingual fractures originating from the inferior border cut (odds ratio [OR] = 1.54; 95% confidence interval [CI], 1.27-1.86; P < .01), with a significantly more posterior relation of the fracture line to the mandibular canal (OR = 2.11; 95% CI, 1.22-3.63; P < .01) and foramen (OR = 1.99; 95% CI, 1.28-3.08; P < .01). No bad splits occurred with the angled design, whereas 3 bad splits occurred with the conventional design, although this difference was not statistically significant (OR = 1.11; 95% CI, 0.99-1.25; P = .07). IAN status was comparable between designs, although the nerve more frequently required manipulation from the proximal mandibular segment when the conventional design was used (OR = 1.21; 95% CI, 0.99-1.47; P = .06). CONCLUSION The results suggest that the angled osteotomy design promotes a more posterior lingual fracture originating from the inferior border cut and a trend was apparent that this also might decrease the incidence of bad splits and IAN entrapment. These results must be carefully extrapolated to the clinical setting, with future studies clarifying these findings.

Removal of bicortical screws and other osteosynthesis material that caused symptoms after bilateral sagittal split osteotomy: a retrospective study of 251 patients, and review of published papers

Rigid fixation with either bicortical screws or miniplates is the current standard way to stabilise the mandibular segments after bilateral sagittal split osteotomy (BSSO). Both techniques are widely used and the superiority of one or other method is still debatable. One complication of rigid fixation is the need to remove the osteosynthesis material because of associated complaints. The main aim of this retrospective study was to analyse how often we needed to remove bicortical screws because they caused symptoms after BSSO in our clinic. Review of other published papers also enabled us to investigate the reported rates of removal of screws and miniplates at other centres. The mean (SD) duration of follow-up of 251 patients (502 sites) was 432 (172) days, and the number of bicortical screws removed in our clinic was 14/486 sites (3%). Other methods of fixation were used at 16 sites. We found no significant association between removal of bicortical screws and age, sex, presence of third molars, or bad splits. Published rates of removal of bicortical screws and miniplates are 3.1%-7.2% and 6.6%-22.2% per site, respectively. These findings show that fixation with bicortical screws after BSSO is associated with a low rate of removal of osteosynthesis material. Reported incidences imply a lower rate of removal for screws than for miniplates.

Bilateral sagittal split osteotomy in a mandible previously reconstructed with a non-vascularized bone graft

We report a bilateral sagittal split osteotomy (BSSO) in a reconstructed mandible. A 28-year-old woman underwent a segmental mandibulectomy due to a multicystic ameloblastoma in the left jaw. After primary plate reconstruction, final reconstruction was performed with a left posterior iliac crest cortico-cancellous autograft. Due to a pre-existing Class II malocclusion, the patient was analyzed for combined orthodontic-surgical treatment. Subsequently, after 1 year of orthodontic treatment, the BSSO was planned. The sagittal split was performed in the remaining right mandible and on the left side in the iliac crest cortico-cancellous autograft. Ten months later, oral rehabilitation was completed with implant placement in the neomandible. Follow-up showed a Class I occlusion, with good function. The patient was very satisfied with the functional and aesthetic results. This case shows that a BSSO can be performed in a reconstructed mandible, without side effects and with good functional and aesthetic results.

Coronectomy of the mandibular third molar: Respect for the inferior alveolar nerve

The aim of this study was to evaluate the outcomes of coronectomy as an alternative surgical procedure to complete removal of the impacted mandibular third molar in patients with a suspected close relationship between the tooth root(s) and the mandibular canal. A total of 151 patients underwent coronectomy and were followed up with clinical examinations and panoramic radiographs for a minimum of 6 months after surgery. None of the patients exhibited inferior alveolar nerve injury. Eruption of the retained root(s) was more frequent in younger patients (18-35 years). Thirty-six patients (23.8%) exhibited insufficient growth of new bone in the alveolar defect, and 11.3% required a second surgical procedure to remove the root remnant(s). Our results indicate that coronectomy can be a reliable alternative to complete removal of the impacted mandibular third molar in patients exhibiting an increased risk of damage to the inferior alveolar nerve on panoramic radiographs.