Myron R. Tucker

Arterial blood gas levels after midazolam or diazepam administered with or without fentanyl as an intravenous sedative for outpatient surgical procedures

The purpose of this study was to compare arterial blood gas measurements made during the baseline, initial sedation, maintenance, and recovery periods in patients sedated with midazolam and saline (MS), midazolam and fentanyl (MF), diazepam and saline (DS), and diazepam and fentanyl (DF). During induction both the MF and the DF groups had significantly lower average PO2, pH, and O2 saturations and significantly higher PCO2 values than either the MS or the DS group. While the differences were not as great, the same was also true during the maintenance phase of the procedure. During recovery, patients receiving MF had lower average PO2, pH, and O2 saturation and higher PCO2 values than the MS or the DF group. Patients receiving MF had significantly lower average PO2, pH, and O2 saturation levels and significantly higher average PCO2 levels during all three postsurgical periods than at baseline. Patients receiving DF had significantly lower average PO2, pH, and O2 saturation levels and significantly higher Pco2 levels during both induction and maintenance than at baseline.

Internal screw fixation: Comparison of placement pattern and rigidity

Multiple screw placement patterns and techniques have been described for fixation of the sagittal split ramus osteotomy. This study evaluated transverse strength (rigidity) of six groups of simulated sagittal osteotomies fixed with different screw patterns and placement techniques. Osteotomies fixed with screws placed in an inverted L pattern were significantly more rigid than those fixed with screws placed in a linear pattern or K-wires placed in a triangular pattern (P less than .05). No significant difference in rigidity was noted between compression and bicortical screws placed in identical patterns.

Histomorphometric evaluation of stress shielding in mandibular continuity defects treated with rigid fixation plates and bone grafts

Histomorphometric techniques were used to evaluate the stress shielding effect in bilateral bone grafts in 4 Macaca fascicularis monkeys. Bilateral continuity defects were created and grafted by replacing the resected portion of the mandible and iliac crest bone into the defect area. Both sides were plated with rigid internal fixation plates. Three months after bone grafting, the plate was removed from one side while the other plate was left in place. The animals were sacrificed at 1, 4, 6, and 8 months after plate removal and the grafted areas removed for histomorphometric analysis. This study documents decreased bone volume as well as smaller interlabel width on the plated side, suggesting a stress shielding effect as a result of the rigid internal fixation plate.

Coronoid process hyperplasia causing restricted opening and facial asymmetry

A case of coronoid process hyperplasia is presented. The primary presenting complaint and clinical feature was restriction of opening, although there was marked facial asymmetry in the area of the right zygoma. Presurgical documentation of this anatomic variation by routine radiography and computed tomography with sagittal reconstruction is presented.

The effectiveness of flumazenil in reversing the sedation and amnesia produced by intravenous midazolam

In this double-blind study 31 outpatients undergoing third molar extraction were randomly assigned to one of two groups. All patients were sedated with intravenous midazolam (IV) by titration method. The flumazenil group (n = 20) received an average of 0.8 +/- 0.17 mg of flumazenil IV. The placebo patients (n = 11) each received 10 mL of normal saline. By both observer and patient alertness ratings, patients receiving flumazenil appeared significantly more alert than placebo patients at 5, 15, 30, and 60 minutes following reversal. After reversal the flumazenil group had significantly higher scores than the placebo group at all intervals through 60 minutes. All the patients receiving flumazenil were able to walk without assistance at 5 minutes, compared with only one patient in the placebo group, and more patients in the flumazenil group recognized the picture card shown to them at 5, 15, 30, and 60 minutes postreversal. Flumazenil is effective in terminating the amnestic properties of midazolam, but this appears to occur to a lesser extent than the reversal of its sedative properties.

Autogenous auricular cartilage implantation following discectomy in the primate temporomandibular joint

The purpose of this study was to evaluate the histologic changes in primate temporomandibular joints (TMJ) treated with autogenous auricular cartilage grafts following total discectomy. Four Macaca fascicularis monkeys underwent bilateral TMJ disc removal and high condylar shaves. One TMJ in each monkey was treated by grafting autogenous auricular cartilage to the glenoid fossa; the contralateral joint served as a control. Monkeys were killed at 6, 12, 16, and 24 weeks postoperatively. Viable auricular cartilage was found in all grafted joints. There was a variable amount of fibrous connective tissue surrounding the cartilage grafts, with some grafts being directly fused to the glenoid fossa. One joint showed significant fibrous connective tissue adhesions between the condylar surface and the inferior portion of the graft. Degenerative changes in the grafted joint appeared grossly to be less severe than in the control joints. The cartilaginous tissues appeared to be a suitable autogenous tissue graft, maintaining its viability and functioning as an interpositioning material between the condyle and fossa.

Orthognathic surgery versus orthodontic camouflage in the treatment of mandibular deficiency

Surgical correction of Class II malocclusions, when associated with mandibular deficiency, often has improved results with combined orthodontic and surgical correction compared with orthodontic treatment alone. Strong consideration of surgical correction of mandibular deficiency should be based on the following questions: 1) Do the patients goals for treatment place a high priority on improvement in facial esthetics? As a corollary, even patients who are not particularly concerned with facial esthetics, but who may have a worsening in facial appearance as a result of orthodontic camouflage, should be considered for surgical correction. This may include patients with lack of upper lip support, an obtuse nasolabial angle, a large nose, and a long lower face height, all of which may become more apparent as a result of orthodontic camouflage treatment. 2) Are the orthodontic movements required in excess of the envelope of discrepancy so that adequate orthodontic correction may not be achieved? 3) Could orthodontic-surgical treatment result in a significant decrease in treatment time? An example would be when surgical treatment in combination with orthodontics could be accomplished without extraction, whereas orthodontic treatment alone would require extraction and space closure. 4) Is there adequate patient compliance? Would orthodontic treatment alone be as ineffective without adequate patient cooperation? 5) Are the risks of surgery within acceptable levels? Are the benefits of surgical treatment, as previously described, obvious?

Autogenous dermal grafts for repair of temporamandibular joint disc perforations

In five Macaca fascicularis monkeys bilateral 5-mm perforations of the intra-articular disc were followed by unilateral repair with autogenous dermal grafts. The monkeys were killed at three, six, 12, 24, and 36 weeks after surgery. The temporomandibular joints (TMJs) were removed en bloc, decalcified, and sectioned in the sagittal plane for histologic examination. All of the control untreated disc perforations, with the exception of one, failed to heal. With all of the grafted disc perforations, viable dermis and fibrous connective tissue proliferation were seen in the area of the repaired perforation. Therefore, autogenous dermal grafting appears to be an acceptable technique for repair of the damaged disc in degenerative joint disease of the TMJ.

Uniaxial pullout evaluation of internal screw fixation

Multiple techniques of internal screw fixation are being used in clinical oral and maxillofacial surgery. This study evaluated the uniaxial pull-out strength of five commonly used screws and Kirschner pins placed by five different techniques. The pull-out strength of the Kirschner pins was significantly less (P greater than .0001) than that of the screws. The screw techniques did not differ significantly.

Sensory retraining after orthognathic surgery: Effect on patient report of altered sensations

INTRODUCTION The purpose of this analysis was to determine whether, over a 2-year period after bilateral sagittal split osteotomy, patients who received facial sensory-retraining exercises with standard opening exercises in the first 6 months after surgery were as likely to report an alteration in facial sensation as those who received standard opening exercises only. METHODS 186 subjects were enrolled in a multi-center, double-blind, stratified-block, randomized clinical trial with 2 parallel groups. Patient reports of altered sensations were obtained before surgery, and 1, 3, 6, 12, and 24 months after surgery. A marginal model was fit to examine the effect of sensory retraining while controlling for potential explanatory effects related to demographic, psychological, and clinical factors on the odds of postoperative altered sensations being reported. RESULTS Age (P <0.0001) and severity of presurgical psychological distress (P <0.0001) were significantly associated with the presence of altered sensations after controlling for the exercise training received. After controlling for age and psychological distress, patients who received opening exercises only were approximately 2.2 times more likely to report postoperative altered sensations than those who also received sensory-retraining exercises (P <0.03). CONCLUSIONS These results suggest that a simple noninvasive exercise program started shortly after orthognathic surgery can lessen the likelihood that a patient will report altered sensations in the long term after orthognathic surgery.