One-stage approach to the correction of facial skeletal deformity with malocclusion

A total of 40 patients with varying degrees of facial skeletal deformity and Class III malocclusion were treated by bimaxillary osteotomy combining maxillo-malar augmentation and/or osseous genioplasty at the same sitting by the author. In all patients, the maxillary advancement and mandibular set back were performed, using Le Fort I maxillary osteotomy and bilateral sagittal split osteotomy of the mandibular rami. In additional bimaxillary osteotomy, simultaneous maxillo-malar augmentation and genioplasty in 20 patients, genioplasty in 12 patients, maxillo-malar augmentation in eight patients, were performed to improve facial harmony. All patients were followed clinically and radiographically for at least 1 year and as much as 5 years after undergoing surgical correction. No cases with relapse or other major complications have been encountered up to now. There were, however, persisting unilateral inferior alveolar nerve damage in two patients, prolonged nerve anesthesia or hypoesthesia in four patients, and short period anesthesia or hypoesthesia in 11 patients, wide alar base in three patients and slight deviation of cartilage septum in two patients. There were no other complications encountered and an unexpected result. The facial skeletal deformity and malocclusion were always treated satisfactorily as patient and plastic surgeon's expectations in one-stage operation, without significant complications and morbidity.     

Effect of modified bilateral sagittal split osteotomy on inferior alveolar nerve neurosensory disturbance

The aim of this study was to assess the occurrence of neurosensory disturbance of the inferior alveolar nerve (IAN) following modified mandibular bilateral sagittal split osteotomy (BSSO) that preserves the mandibular inferior border. All patients undergoing BSSO, associated or not with a Le Fort I osteotomy (performed by the same senior operator) between January 2018 and December 2019, were eligible. The modified BSSO consists of a modification of the technique described by Epker: the bony section of the buccal cortex stops 3-4 mm above the basal mandibular edge. While respecting the basilar border, sectioning is then performed up to the gonial angle where bicortical section is finally performed. Sensibility of the labial and chin area was evaluated immediately postoperatively, and at six months and two years of follow up. A total of 140 eligible patients underwent the modified BSSO between January 2018 and December 2019, and 72 were included. Hypoaesthesia was found in 81.9% of the patients (59/72 patients) at initial evaluation. It decreased to 45.8% (33/72 patients) at the six-month examination and to 12.5% (9/72 patients) at the last examination. Four bad splits were recorded. The modified BSSO preserves the inferior border of the mandible and maintains the IAN in the lingual fragment. There is no need to release the IAN, hence its manipulation is reduced and the incidence of IAN postoperative hypoaesthesia is also reduced.     

A prospective electromyographic and computer-aided thermal sensitivity assessment of nerve lesions after sagittal split osteotomy and Le Fort I osteotomy.

PURPOSE: The purpose of this study was to determine the incidence of temporary and permanent sensory disturbance of the inferior alveolar nerve (IAN) after bilateral sagittal split osteotomy (BSSO) of the mandible and of the infraorbital nerve (ION) after Le Fort I osteotomy, as well as the rate of recovery of sensory function using subjective and objective measures. PATIENTS AND METHODS: Preoperatively and after 1 week, and 1, 3, 6, and 12 months postoperatively, sensibility in the distribution of 36 IONs after Le Fort I osteotomy and 24 IANs after BSSO in 19 patients were investigated by using sharp-blunt testing, 2-point discrimination, electromyographic recording, and thermal sensitivity (Pain and Thermal Sensitivity Test Device [PATH]) tests of the Adelta and C nerve fibers. RESULTS: With conventional clinical sharp-blunt and 2-point discrimination tests, the incidence of temporary impairment was 81% for the ION (29 of 36) and 83% for the IAN (20 of 24). The rate of permanent sensibility disturbance with conventional clinical testing was 6% for the ION and 15% for the IAN. Obvious recovery was found after 1 to 3 months for the ION, but it took 6 to 12 months for the IAN. In contrast, electromyography (EMG) testing showed lower rates of temporary sensory disturbance, namely, 54% (13 of 24) for the ION and 68% (15 of 22) for the IAN. Permanent sensory losses were not found. The results of the EMG test was confirmed by the PATH test. CONCLUSIONS: Objective tests for sensory disturbances show lower rates than the conventional tests. For quality control, preoperative and postoperative measurement and documentation of postoperative recovery of sensation is recommended.     

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.     

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.     

Influence of BSSO surgical technique on postoperative inferior alveolar nerve hypoesthesia: A systematic review of the literature

ObjectiveThe aim of this study was to evaluate the influence of different splitting techniques, namely, “mallet and chisel” versus “spreading and prying”, used during bilateral sagittal split osteotomy (BSSO) on postoperative hypoesthesia outcomes.Study designWe systematically searched the PubMed and Cochrane databases (from January 1957 to November 2012) for studies that examined postoperative neurosensory disturbance (NSD) of the inferior alveolar nerve (IAN) after BSSO.ResultsOur initial PubMed search identified 673 studies, of which, 14 met our inclusion criteria. From these 14 studies, 3 groups were defined: (1) no chisel use (4.1% NSD/site), (2) undefined chisel use (18.4% NSD/site), and (3) explicit chisel use along the buccal cortex (37.3% NSD/site).ConclusionStudy heterogeneity and a frequent lack of surgical detail impeded our ability to make precise comparisons between studies. However, the group of studies explicitly describing chisel use along the buccal cortex showed the highest incidence of NSD. Moreover, comparison of the study that did not use chisels with the 2 studies that explicitly described chisel use revealed a possible disadvantage of the “mallet and chisel” group (4.1% versus 37.3% NSD/site). These results suggest that chisel use increases NSD risk after BSSO.     

Soft tissue changes after mandibular setback and bimaxillary surgery in Class III patients

Objective:To evaluate the relationship between soft tissue and bone structure for Class III patients before and after bilateral sagittal split osteotomy (BSSO) and bimaxillary orthognathic surgery; to determine the impact of other factors on soft tissue change; and to evaluate correlations between thickness of tissue before surgery, SNA, SNB, and ANB angles, and soft tissue changes.Materials and Methods:The study included 78 Class III patients treated only with BSSO or with BSSO and Le Fort I osteotomy. Lateral cephalograms were taken before and 3 months to 1 year after surgery. After all points of the Zagreb82 and Legan and Burstone profile analysis were traced, the ratio of five soft tissue points before and after surgery was evaluated.Results:Soft tissue between points Sn and A and upper lip showed statistically significant changes for patients treated with bimaxillary surgery and BSSO. Only gender had an influence on soft tissue change. The correlation between soft tissue thickness and changes after surgery was significant. A change in SNB angle correlated with upper lip thickness for patients treated with BSSO but not for patients treated with BSSO and Le Fort I. SNA angle changes correlated with soft tissue changes between points Sn and A.Conclusion:Results of this study show soft tissue changes after BSSO and BSSO and Le Fort I and eliminate the deficiencies that were indicated in the meta-analysis of soft tissue changes from a previous study.     

Neurosensory disturbances one year after bilateral sagittal split mandibular ramus osteotomy performed with separators.

BACKGROUND: The most frequently performed osteotomy for correction of mandibular retrognathia is a bilateral sagittal split ramus osteotomy. Permanent neurosensory disturbance of the inferior alveolar nerve is one of the most frequently and severe complications. Many authors have reported this, but the incidence differs widely. In the recent literature, only four authors have reported a percentage of less than 10% after 1 year follow-up. OBJECTIVE: To determine the incidence of permanent neurosensory disturbance of the inferior alveolar nerve after bilateral sagittal split ramus osteotomy, and possible influences of the technique used. PATIENTS AND METHODS: A series of 109 patients is reported who underwent a bilateral sagittal split mandibular ramus osteotomy with the use of separators and without the use of chisels. The segments were hold by rigid transbuccal screw fixation. RESULTS: The incidence of neurosensory disturbances 1 year after surgery was 8.3%. CONCLUSION: The use of sagittal split separators without the use of chisels, may play an important role in the relatively low percentage of persistent hypoaesthesia of the inferior alveolar nerve.     

Stability of the Le Fort I osteotomy with anterior internal fixation alone: a case series.

PURPOSE: The purpose of this case series was to evaluate the late postsurgical stability of the Le Fort I osteotomy with anterior internal fixation alone and no posterior zygomaticomaxillary buttress internal fixation. PATIENTS AND METHODS: Sixty patients with maxillary vertical hyperplasia and mandibular retrognathia underwent a 1-piece Le Fort I osteotomy of the maxilla with superior repositioning and advancement or setback. A bilateral sagittal split ramus osteotomy for mandibular advancement was also performed in 22 patients. Stabilization of each maxillary osteotomy was achieved using transosseous stainless steel wires and/or 3-hole titanium miniplates in the piriform aperture region bilaterally, with no zygomaticomaxillary buttress internal fixation. (Twelve of the 60 identified patients were available for a late postoperative radiographic evaluation.) Lateral cephalometric radiographs were taken preoperatively (T1), early postoperatively (T2), and late postoperatively (T3) to analyze skeletal movement. RESULTS: These 12 patients (5 male, 7 female) had a mean age of 24.5 years at surgery. Mean time from surgery to T2 was 41.2 days; mean time from surgery to T3 was 14.8 months. One patient received anterior wire osteosynthesis fixation, while 11 patients received both anterior titanium miniplate internal skeletal fixation and anterior wire osteosynthesis fixation. Six patients underwent Le Fort I osteotomy with genioplasty, 1 patient underwent Le Fort I osteotomy with bilateral sagittal split ramus osteotomy, and 5 patients underwent Le Fort I osteotomy with bilateral sagittal split ramus osteotomy and genioplasty. These 12 patients all underwent maxillary superior repositioning with either advancement (11 patients) or setback (1 patient). Statistically significant surgical (T2-T1) changes were found in all variables measured. In late postsurgical measurements (T3-T2), all landmarks in the horizontal and vertical plane showed statistically significant skeletal stability. CONCLUSION: This case series suggests that anterior internal fixation alone in cases of 1-piece Le Fort I maxillary superior repositioning with advancement has good late postoperative skeletal stability.     

Operative time,length of stay and reoperation rates for orthognathic surgery

Orthognathic surgery improves quality of life in terms of oral function and facial aesthetics. Our aim was to establish and compare operative time and length of inpatient stay for orthognathic procedures, and to assess the reoperation rate. Departmental electronic data base was used to identify all patients undergoing orthognathic surgery in a single unit between the 01/01/2016 and the 01/08/2018. 251 patients were identified who underwent 409 orthognathic surgery procedures. The mean operating time for a bimaxillary osteotomy (n=107) was 139.3 min. For single jaw procedures, the mean operating time for a Le Fort I osteotomy (n= 42) was 82.2 min and for a bilateral sagittal split osteotomy (BSSO) (n= 102) was 80.3min. Bimaxillary osteotomy combined with genioplasty (n=17) this increased the operating time on average by 31 min. and of a BSSO combined with a genioplasty (n=14) by 27 mins. The mean postoperative hospital stay was 1.2 ± 0.2 days. 96.4% patients spent only one postoperative night in hospital. 6/251 (2.4%) patients required re-operation. In regression analysis, age was the only significant factor in increasing length of stay (p<0.008), 95% CI 0.03-0.2). Our review shows short operating times and postoperative inpatient stays in a large cohort of patients undergoing orthognathic surgery. This is combined with a low reoperation rate. This may point to a patient benefit from high volume orthognathic centres.     

Positional changes of the masseter and medial pterygoid muscles after surgical mandibular advancement procedures: an MRI study

This study evaluated whether surgical mandibular advancement procedures induced a change in the direction and the moment arms of the masseter (MAS) and medial pterygoid (MPM) muscles. Sixteen adults participated in this study. The sample was divided in two groups: Group I (n=8) with a mandibular plane angle (mpa) <39° and Group II (n=8) with an mpa >39°. Group I patients were treated with a bilateral sagittal split osteotomy (BSSO). Those in Group II were treated with a BSSO combined with a Le Fort I osteotomy. Pre- and postoperative direction and moment arms of MAS and MPM were compared in these groups. Postsurgically, MAS and MPM in Group II showed a significantly more vertical direction in the sagittal plane. Changes of direction in the frontal plane and changes of moment arms were insignificant in both groups. This study demonstrated that bimaxillary surgery in patients with an mpa >39° leads to a significant change of direction of MAS and MPM in the sagittal plane.     

Endoscopically assisted Le Fort I osteotomy to correct transverse and sagittal discrepancies of the maxilla.

PURPOSE: The purpose of this report was to show the feasibility of the combination of a minimally invasive endoscopic approach to the maxilla with transverse and sagittal distraction procedures. MATERIALS AND METHODS: Four human cadavers were used for training of a minimally invasive access to the maxilla to perform a endoscopically assisted Le Fort I osteotomy, before this technique was applied in 3 patients with transverse and sagittal growth deficits of the maxilla. Access to the maxilla was gained through a small mucosa incision in the vestibule to create a visualization port to the maxillary sinus through a bur hole. Landmarks were identified through the endoscope before a Le Fort I osteotomy was performed using chisels of different shapes and angulations. In 2 patients the maxilla was split sagittally to perform a transverse maxillary expansion; in 1 patient, a buried distractor was applied close to the piriform aperture to correct a sagittal growth deficit in a hypoplastic maxilla. RESULTS: Endoscopic exposure of the maxillary sinus walls from within the sinus, the accurate identification of landmarks, and the creation of a Le Fort I osteotomy were achieved in all cases. Distractor application close to the piriform aperture rendered good stability. CONCLUSION: The results of these cases indicate that the endoscopic approach to the maxillary sinus allows excellent exposure of the sinus walls to perform a endscopically assisted Le Fort I osteotomy. The combination of endoscopy and osteodistraction processes supports the tendency to perform minimally invasive, less-traumatizing surgical procedures, especially in individuals who are still growing.     

Evaluation of alveolar nerve function after surgical lengthening of the mandible by a bilateral sagittal split osteotomy or distraction osteogenesis

This study compares the effects of bilateral sagittal split osteotomy (BSSO) and distraction osteogenesis (DO) for lengthening the mandible regarding loss of function of the inferior alveolar nerve (IAN). In a retrospective cohort study design, the function of the IAN was tested with a Weinstein monofilament 3.22, 1 year after the surgical procedure in 65 patients (35 BSSO; 30 DO). This was defined as the upper limit for normal function. Of 130 IAN studied (70 BSSO, 54%; 60 DO, 46%), nerve function was disturbed in 23 (18%). In this group, 14 cases (61%) had undergone BSSO and 9 (39%) DO. One-hundred and seven nerves had no neurosensory IAN changes; of these BSSO had been performed in 56 cases (52%) and DO in 51 cases (48%). After eliminating confounding factors, there was no significant difference in the occurrence of neurosensory changes between the treatment options (DO versus BSSO, odds ratio: 1.254 with 95% CI: 0.366–4.300). In conclusion, there was no difference in IAN function between patients treated with BSSO or DO for lengthening the mandible.     

The role of intraoperative positioning of the inferior alveolar nerve on postoperative paresthesia after bilateral sagittal split osteotomy of the mandible: prospective clinical study

Bilateral sagittal split osteotomy (BSSO) aims to correct congenital or acquired mandibular abnormities. Temporary or permanent neurosensory disturbance is the most frequent complication of BSSO. To evaluate the influence of IAN handling during osteotomy, the authors undertook a prospective study in 290 patients who underwent BSSO. The occurrence and duration of paresthesia was evaluated 4 weeks, 3 months, 6 months, and 1 year after surgery. Paresthesia developed immediately after surgery in almost half of the patients. Most cases of paresthesia resolved within 1 year after surgery. A significantly higher prevalence of paresthesia was observed on the left side. The authors found a correlation between the type of IAN position between the left and right side. The type of split (and IAN exposure) did not have a significant effect on the occurrence or duration of neurosensory disturbance of the IAN. The authors did not find a correlation between the occurrence and duration of paresthesia and the direction of BSSO. Mandibular hypoplasia or mandibular progenia did not represent a predisposition for the development of paresthesia. In the development of IAN paresthesia, the type of IAN exposure and the split is less important than the side on which the split is carried out.     

The impact of Le Fort I advancement and bilateral sagittal split osteotomy setback on ventilation during sleep

The impact of orthognathic surgery for class III malocclusion on ventilation during sleep was examined using a comparison of pre- and post-surgical respiratory parameters. 21 patients with both maxillary hypoplasia and mandibular excess underwent Le Fort I osteotomy and advancement together with bilateral sagittal split osteotomy (BSSO) setback. Respiratory parameters, ECG and position of the body were monitored before surgery and postoperatively after the fixation removal (mean 8.5 months). Average Le Fort I advancement was 4.44 mm, BSSO setback was 4.96 mm. Generally, the orthognathic procedure worsened breathing function during sleep, as reflected in significant increase of index of flow limitations and decrease in oxygen saturation. The posterior airways space decreased to 75% of its original volume, the distance between mandibular plane and hyoid bone increased to 133%. The results indicate that bimaxillary surgery for class III malocclusion increased upper airway resistance. A young person would probably be able to balance such a decline in respiratory function using different adaptive mechanisms, but the potential impact of orthognathic surgery on the upper airways should be incorporated in a treatment plan.     

An accurate bimaxillary repositioning technique using straight locking miniplates for the mandible-first approach in bimaxillary orthognathic surgery

Bimaxillary orthognathic surgery has been widely performed to achieve optimal functional and esthetic outcomes in patients with dentofacial deformity. Although Le Fort I osteotomy is generally performed before bilateral sagittal split osteotomy (BSSO) in the surgery, in several situations BSSO should be performed first. However, it is very difficult during bimaxillary orthognathic surgery to maintain an accurate centric relation of the condyle and decide the ideal vertical dimension from the skull base to the mandible. We have previously applied a straight locking miniplate (SLM) technique that permits accurate superior maxillary repositioning without the need for intraoperative measurements in bimaxillary orthognathic surgery. Here we describe the application of this technique for accurate bimaxillary repositioning in a mandible-first approach where the SLMs also serve as a condylar positioning device in bimaxillary orthognathic surgery.     

Endoskopisch unterstützte LeFort-I-Osteotomie bei Distraktionsverfahren im Oberkiefer

Purpose. The purpose of this study was to demonstrate the feasibility of combining a minimally invasive endoscopic approach to the maxilla with transverse and sagittal distraction procedures. Materials and methods. Four human cadavers were used for training of a minimally invasive access to the maxilla to perform an endoscopically assisted Le Fort I osteotomy, before this technique was applied in three patients with transverse and sagittal growth deficits of the maxilla. Access to the maxilla was gained through a small mucosa incision in the vestibule to create a visualization port to the maxillary sinus through a bur hole. Landmarks were identified through the endoscope before a Le Fort I osteotomy was performed using straight and angulated chisels of different form and angulation. In two patients, the maxilla was split sagittally to perform a transverse maxillary expansion. In one patient, a buried distractor was applied close to the piriform aperture to correct a sagittal growth deficit in a hypoplastic maxilla. Results. The endoscopic exposure of the maxillary sinus walls from within the sinus, the accurate identification of landmarks, and the creation of a Le Fort I osteotomy was achieved in all cases. Distractor application close to the piriform aperture rendered good stability. Conclusion. The results of these case reports indicate that the endoscopic approach to the maxillary sinus allows excellent exposure of the sinus walls to perform an endoscopically assisted Le Fort I osteotomy. The combination of endoscopy and osteodistraction supports the trend toward minimally invasive, less traumatic surgical procedures, especially in individuals still growing.     

Risk factors of nerve injury during mandibular sagittal split osteotomy

There is little objective data about whether surgical technique or mandibular anatomy are a risk for inferior alveolar nerve (IAN) injury during bilateral sagittal split osteotomy (BSSO). Orthodromic sensory nerve action potentials (SNAPs) of the IAN were continuously recorded on both sides in 20 patients with mandibular retrognathia during BSSO operation. Changes in latency, amplitude, and sensory nerve conduction velocity (SNCV) at baseline and at different stages of the operation were analyzed. The SNAP latencies prolonged, the amplitudes diminished, and the SNCVs slowed down during BSSO (P = 0.0000 for all parameters). The most obvious changes occurred during surgical procedures on the medial side of the mandibular ramus. There was a clear tendency towards more disturbed IAN conduction with longer duration of these procedures (right side R = -0.529. P = 0.02; left side R = -0.605, P = 0.006). Exposure or manipulation of the IAN usually had no effect on nerve function, but the IAN conduction tended to be more disturbed in cases with nerve laceration. Low corpus height (R = 0.802, P = 0.001) and the location of the mandibular canal near the inferior border of the mandible (R = 0.52, P = 0.02) may increase the risk of IAN injury. There was no correlation between the age of the patients and the electrophysiological grade of nerve damage.     

Condylar and temporomandibular joint disc positions after mandibular osteotomy for prognathism

PURPOSE: The purpose of this study was to compare the changes in temporomandibular joint (TMJ) morphology and clinical symptoms after sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) with and without a Le Fort I osteotomy. PATIENTS AND METHODS: Of 43 patients with a diagnosed jaw deformity, 20 underwent IVRO without internal fixation and 23 underwent SSRO with rigid internal fixation. Some operations were performed in combination with a Le Fort I osteotomy. The TMJ symptoms and joint morphology, including the disc position, were assessed preoperatively and postoperatively using magnetic resonance imaging (MRI) and axial cephalography. RESULTS: A significant difference in the direction of condylar rotation was seen in horizontal axial cephalography images (P <.01). Fewer or no TMJ symptoms were reported postoperatively by 88% of the patients who underwent IVRO with or without a Le Fort I osteotomy and by 66.7% of patients who underwent SSRO with or without a Le Fort I osteotomy. In sagittal images, no change was seen in anterior disc displacement after SSRO; however, improvement was seen in 44.4% of patients with anterior disc displacement who underwent IVRO with or without a Le Fort I osteotomy. CONCLUSION: These results suggest that SSRO does not improve anterior disc displacement; IVRO improves anterior disc displacement in the initial postsurgical period, and both procedures may improve TMJ symptoms.