Robert A. Bays

Surgically assisted rapid palatal expansion: An outpatient technique with long-term stability

This study presents the results of surgically assisted rapid palatal expansion done on an outpatient basis in 19 patients with a mean age of 30 years. Postsurgical and postorthodontic evaluation (mean, 2.4 years) showed a mean relapse rate of 8.8% in the canine region, 1% in the premolar region, and 7.7% in the molar region. These results show that the surgical procedure is feasible on an outpatient basis and the technique, as outlined, yields a stable long-term result.

Complications of orthognathic surgery

Evidenced-based medicine criteria are becomingthe standards by which clinical studies are rated [1].Articles that evaluate clinical outcomes can be cate-gorized according to a hierarchy of evidence-basedmedicine. The strongest evidence is that derived fromrandomized, clinical trials or, even better, a meta-analysis of several randomized, controlled trials. Thenextstrongestevidenceisderivedfromcohortstudies.This is followed by evidence that is derived fromcase control series. Isolated case reports provide theweakest evidence in this hierarchy. Numerous chap-ters in various texts have reported a wide spectrum ofcomplications of orthognathic surgery based on allfour of these types of evidence. Little has been addedin the recent literature regarding the range or typesof complications. A few studies have tightened ourfocus on the already known complications of or-thognathic surgery with regard to prevalence andseverity. This article concentrates on studies thatreport complications with the weight of randomizedclinical trials or cohort studies. Where possible, ametaanalysis has been performed to provide the high-est level of evidence-based medicine. Means for allstatistics are weighted to account for the differentsample sizes. Where original publications providedadequate information, confidence intervals (error barson figures) were determined that allow the reader todetermine the range that is required to be 95% certainthat if the study were repeated the new mean wouldfall within that range. Where narrow confidenceintervals are shown, this suggests a high degree ofprecision and reproducibility. When the confidenceinterval crosses the null value (ie, 0%), the results arenot statistically significant, although they may stillbe clinically important.Neurosensory changesInferior alveolar nerve injuryAlthough inferior alveolar nerve (IAN) injury hasbeen reported as a result of several mandibularoperations, its association with the bilateral sagittalsplit osteotomy (BSSO) is well documented [2–8].Evaluation of these studies is confounded by thenumerous techniques that have been used to performthe operation and methods and timing of postsurgicalneurosensory changes. Variations in techniqueinclude the use of burs, saws, blunt or heavy chisels,sharp, thin chisels, and spreaders to complete theosteotomy. The method of fixation may includeinterosseous wiring plus intermaxillary fixation,bicortical lag screws, bicortical position screws,monocortical plates, or a combination of these. Thereis no ‘‘standard technique’’ to provide guidance, andoutcome study comparison is difficult.For BSSO with rigid internal fixation (RIF), thepostoperative incidence of IAN neurosensory lossvaries from 0% to 75% (Table 1), with a mean of35% for subjective reporting and 33% for objectivetesting at a mean follow-up of 21 months [2–8](Fig. 1). The methods of data collection for subjectiveand objective parameters vary considerably, whichwould be likely to influence the results. Whether the

Risk factors for infection following operative treatment of mandibular fractures : a multivariate analysis

Utilizing a retrospective study design and a study sample of 284 consecutive patients, we measured the association between five different risk factors and the development of infection following the operative management of mandibular fractures. The five risk factors analyzed were age, sex, number of fractures per patient, time from admission to treatment, and treatment modality. The overall infection rate was 5.3 percent. The infection rate for each treatment modality was (1) 0 percent for closed reduction, (2) 20.0 percent for open reduction and internal fixation with wire osteosynthesis, and (3) 6.3 percent for open reduction and rigid internal fixation. To measure the association between the various risk factors and postoperative infection, we used multivariate logistic regression. After controlling for potential confounding variables, the only risk factor statistically associated with postoperative infection was treatment modality.

Osteoarthrosis of the temporomandibular joint following experimental disc perforation in Macaca fascicularis.

The aim of this experiment was to study the sequela of experimental temporomandibular joint (TMJ) disc perforation. Each TMJ of four Macaca fascicularis adult monkeys was surgically exposed, and a 4- to 6-mm perforation at the posterolateral portion of the avascular disc was produced by electrosurgery. Four monkeys were used as controls. The animals were killed 11 weeks (two experimental and two controls) or 12 weeks (two experimental and two controls) after disc perforation. The perforations were increased in size in five joints, and healed in one joint. In addition, two joints of one animal showed complete loss of the disc, denudation of articular surfaces, and bone-to-bone contact. In contrast to control joints, the experimental joints exhibited the following changes histopathologically: thick, highly cellular and fibrillated fibrous coverings of articular surfaces (five joints); marked hyperplasia of synovial membrane; migration of synovial cells on the surfaces of the disc and margins of perforation; multiple adhesions of disc to articular surfaces; increase in cellularity and vascularity of discs; and chondrocytic clustering in temporal fibrous covering; and osteophytes of condylar and temporal components and focal or complete denudation of articular surfaces (2 joints). Most of these changes were consistent with the diagnosis of osteoarthritis. From this study, one can conclude that disc perforation can lead to osteoarthritis.

Evaluation of long-term sensory changes following mandibular augmentation procedures

Having undergone mandibular augmentation using several osteotomy techniques, 12 patients were evaluated for long-term sensory changes in the mental nerve distribution. The mean follow-up period was 32 months. The evaluation included both subjective and objective testing. Objectivity was achieved via the two-alternative forced-choice technique in testing light touch, thermal, and brush directional discrimination. All patients reported persistent subjective neurosensory alteration at the mental nerve distribution, four of which were judged as dysesthetic. Objective sensory alteration was observed in all three modalities tested, with brush directional discrimination most greatly affected, followed by light touch and then thermal discrimination. It was concluded that mandibular augmentation procedures requiring repositioning of the inferior alveolar neurovascular bundle lead to both subjective and objective neurosensory alteration, which were shown to be persistent at long-term follow up.

Maxillary perfusion during Le Fort I osteotomy after ligation of the descending palatine artery

PURPOSE Controversy exists regarding management of the descending palatine artery (DPA) during Le Fort I osteotomy. Some surgeons advocate preserving the DPA, and others ligate the vessels. The purpose of this study was to evaluate maxillary gingival blood flow (GBF) during Le Fort I osteotomy in a sample of patients with and without ligation of the DPA. PATIENTS AND METHODS Using a prospective randomized clinical study, we enrolled a study sample composed of 34 patients undergoing Le Fort I osteotomy. The patients were randomly assigned to either study group 1 (16) (DPA ligated) or group 2 (18) (DPA preserved). To measure maxillary GBF during the operation, we used laser Doppler flowmetry (LDF). The predictor variable was status of DPA management (ligated or preserved). The outcome variable was change in GBF over time. RESULTS (DPA). Before ligation (or simulated ligation) of the DPA, the mean GBF for groups 1 and 2 was 11.4 +/- 8.6 and 11.9 +/- 9.4 mL/min/100 g tissue, respectively (P = .88). After ligation of the DPA in group 1, the mean GBF was 10.0 +/- 7.7 mL/min/100 g tissue. At the corresponding time in group 2 (DPA preserved), the mean GBF was 12.6 +/- 9.4 mL/min/100 g tissue. The difference in mean GBF between groups 1 and 2 was not statistically significant (P = .43). CONCLUSION There were no statistically significant differences in mean maxillary GBF between patients having the DPA ligated and those having the DPA preserved as measured using LDF during Le Fort I osteotomy.

Intraoperative assessment of maxillary perfusion during Le Fort I osteotomy.

Intraoperative maxillary blood flow was measured using laser Doppler flowmetry (LDF) in two groups of patients undergoing orthognathic surgery. Group 1 (n = 14) consisted of patients undergoing Le Fort I osteotomy and group 2 (n = 8) consisted of patients undergoing isolated mandibular osteotomies. In group 1, the mean gingival blood flow (GBF) decreased significantly over time during the course of the operation from 29.5 mL/min/100 g of tissue to 13.2 mL/min/100 g of tissue (P = .0001). The mean GBF did not change significantly over time in group 2 (P = .39). The results of this study demonstrate that 1) LDF may be used to measure intraoperative GBF during Le Fort I osteotomy with an acceptable level of variability, and 2) maxillary GBF decreased significantly over time during Le Fort I osteotomy procedures.

Management of frontal sinus fractures: Review of the literature and clinical update

The purpose of this article is to discuss and analyze the controversial treatment protocols that are currently recommended in the management of frontal sinus fractures. Embryology, anatomy, and diagnostic radiology of the frontal sinus are also discussed.

A comparative study of skeletal and dental stability between rigid and wire fixation for mandibular advancement.

This study examined the skeletal and dental stability after mandibular advancement surgery with rigid or wire fixation for up to 2 years after the surgery. Subjects for this multisite, prospective, randomized, clinical trial were assigned to receive rigid (n = 64) or wire (n = 63) fixation. The rigid cases received three 2-mm bicortical position screws bilaterally and elastics; the wire fixation subjects received inferior border wires and 6 weeks of skeletal maxillomandibular fixation with 24-gauge wires. Cephalometric films were obtained before surgery, and at 1 week, 8 weeks, 6 months, 1 year, and 2 years after surgery. Skeletal and dental changes were analyzed using the Johnstons analysis. Before surgery both groups were balanced with respect to linear and angular measurements of craniofacial morphology. Mean anterior advancement of the mandibular symphasis was 5.5 mm (SD, 3.2) in the rigid group and 5.6 mm (SD, 3.0) in the wire group. Two years after surgery, mandibular symphasis was unchanged in the rigid group, whereas the wire group had 26% of sagittal relapse. Dental compensation occurred to maintain the corrected occlusion, with the mandibular incisor moving forward in the wire group and posteriorly in the rigid group. However, at 2 years after surgery, when most subjects were without braces, the overjet and molar discrepancy had relapsed similarly in both groups.

Effects of hypesthesia on oral behaviors of the orthognathic surgery patient

PURPOSE The purpose of this study was to compare orthognathic surgery patients with and without significant hypesthesia with respect to perceived problems with specific oral behaviors. PATIENTS AND METHODS Data from 116 patients 6 months after bilateral sagittal split osteotomy (BSSO) and mandibular advancement were analyzed. Tactile sensation in the right and left mental nerve areas was determined using monofilaments and brush strokes (von Frey hairs). The right infraorbital region was used as a control. A difference of 450 mg of force between the control and test sites was considered significant hypesthesia. Patients rated their level of subjective problems with swallowing liquids or solids, smiling, spitting, kissing, speaking, eating, and drooling on a scale from 1 (none to mild) to 7 (extreme). A value of 5 or greater was considered significant impairment. RESULTS Hypesthesia was shown in 23 patients (19.8%) with the monofilaments and in 29 patients (25.0%) using brush stroke direction. In each of these two groups, a significant correlation was observed between hypesthesia and difficulty in chewing and kissing. No correlation was observed between any of the remaining seven oral behaviors and hypesthesia. CONCLUSION These findings suggest that only certain oral behaviors are affected by hypesthesia of the mental nerve.