Neurosensory differences after wire and rigid fixation in patients with mandibular advancement.

PURPOSE: The purpose of this analysis was to compare the frequency and severity of nerve damage with rigid and wire fixation in patients participating in a prospective, randomized clinical trial. PATIENTS AND METHODS: One hundred twenty-six patients who required a bilateral sagittal split osteotomy and mandibular advancement were randomly assigned to receive either rigid or wire fixation. Tactile sensation in the mental nerve region bilaterally was determined presurgically and throughout the subsequent 2 years by using monofilament detection and brush stroke direction. Neurosensory levels were compared between the types of fixation over time. RESULTS: Evaluation with monofilament detection showed no significant difference between types of fixation throughout the 2-year follow-up. However, brush stroke determination showed significantly greater hypesthesia with rigid compared with wire fixation from 8 weeks through 2 years postoperatively. CONCLUSION: Rigid fixation resulted in more anesthesia in the mental nerve distribution than wire fixation when tested with brush stroke direction. However, increased anesthesia was not present when measured with monofilament determination.

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.

Hyoid myotomy and suspension for obstructive sleep apnea syndrome.

Hyoid bone suspension with inferior myotomy has been shown to be a successful technique in the treatment of obstructive sleep apnea. However, little mention is made in the literature concerning the details of the surgical procedure. Anatomic details have been given even less attention. This article addresses the regional anatomy, surgical technique, and materials for suspension of the hyoid bone, along with newer modifications of the procedure. Potential risks and complications are also discussed.

The perimeter marking technique for rigid fixation of frontal sinus fractures: procedure and report of cases.

PURPOSE: Fractures of the frontal sinus region frequently need operative intervention in the form of reconstruction and obliteration. This requires removing the anterior table of the frontal sinus to gain access to the floor as well as the entire lateral extent of the sinus. Prior techniques to obtain this access have involved fabrication of preoperative radiographic templates. This article describes a technique of perimeter marking for delineating the precise location of the frontal sinus perimeter without the use of a radiographic template. METHODS: A 7-cm bayonet forceps is used for the perimeter marking. One prong is placed inside the sinus to the maximum peripheral extent and the corresponding prong then reflects its position on the external surface of the outer table. A no. 701 bur in a high-speed drill marks the perimeter adjacent to the bayonet forceps. After sinus marking is complete, the osteotomy is accomplished using either a drill or oscillating saw. RESULTS: Because the exact perimeter of the proposed osteoplastic flap is known prior to the osteotomy, bone plates can be preinserted, removed, and then replaced at the end of the procedure to anatomically reconstruct the frontal contour. Additionally, it is possible to remove a large region of the anterior table during the osteoplasty in one segment. CONCLUSION: This technique creates an unobstructed view of the lateral recesses of the frontal sinus and makes esthetic reconstruction of the frontal bar region possible.

Electromyographic evaluation of continuous passive motion versus manual rehabilitation of the temporomandibular joint.

There have been a myriad of rehabilitation techniques for patients after temporomandibular joint (TMJ) surgery, varying from professionally delivered physical therapy to self use of tongue blades. Most recently continuous passive motion (CPM) has been introduced for postsurgical TMJ patients. The benefits of CPM have been attributed both to its continuous and its passive nature. While the continuous nature of the therapy is accepted, questions remain regarding the passivity of the motion. The purpose of this study was to electromyographically evaluate the degree of activity that occurs with CPM compared with simple mandibular exercises in TMJ rehabilitation. Eight patients who had arthroscopy or arthrotomy were begun on a CPM device postsurgically. Electromyographic data were obtained for jaw closing and opening activity. Patients were measured using CPM as well as tongue depressors. Three different exercises were performed: 1) activity at rest was compared with rest with CPM; 2) opening and closing with CPM versus use of tongue depressors was compared; and 3) maximum opening to a comfortable position was compared using tongue depressors versus the CPM device in a fixed open position. The degree of opening was matched for both groups. A significant difference in electromyographic activity was shown between patients using CPM versus tongue depressors during the open/closing cycles. This suggests that TMJ CPM is truly passive.

Hysteresis in jaw positioning following lateral stretches.

The purpose of this study was to examine hysteresis of the masticatory system following brief, voluntary lateral positioning of the mandible. Hysteresis was studied in ten healthy subjects, as a function of both time and distance that the mandible was held laterally off the midline. So that the effects of distance of lateral stretch on hysteresis could be studied, subjects positioned their jaws to the left or right of the midline distances of 2, 4, 6, 8, and 10 mm for ten s. So that the effects of time could be studied, the distance of lateral stretch was held a constant 8 mm for durations of two, four, six, 12, 16, and 20 s. Following each voluntary lateral stretch, subjects relaxed the muscles using EMG biofeedback and allowed the mandible to reposition itself passively. Hysteresis was defined as the difference in the mandibular resting position between pre- and post-stretch recordings. Mean hysteresis effects ranged from 0.7 mm to 1.8 mm. Hysteresis effects were found to increase with both distance and time; after eight s, however, no additional effect of time was noted.

Electromyographic relaxed mandibular position in long-faced subjects.

Previous articles have presented conflicting results concerning the relationship of EMG rest position in subjects with varying craniofacial morphology. This study sought to resolve the issue by studying long-faced subjects and controlling head position. Our findings showed that long-faced subjects have large EMG rest positions in contrast to the results reported by Wessberg et al. We were not able to resolve the differences between these two studies by variation in head position or lack of consistent sample population. The results of this study and earlier studies question the clinical practice of using EMG rest as a starting point to establish vertical dimension of occlusion.