Helen Giannakopoulos

Biomet Microfixation Temporomandibular Joint Replacement System: A 3-Year Follow-Up Study of Patients Treated During 1995 to 2005

PURPOSE To assess the safety and efficacy of a stock alloplastic total temporomandibular joint (TMJ) implant system, the Biomet Microfixation TMJ Replacement System. MATERIALS AND METHODS During a 10-year multicenter clinical trial from 1995 to 2005, 442 Biomet Microfixation TMJ Replacement Systems were implanted in 288 patients (154 bilaterally and 134 unilaterally). Patients were followed at landmark times, including the date of surgery and at 1 month, 3 months, 1 year, 1 year 6 months, and 3 years. The 3 major metrics that were evaluated were preoperative and postoperative pain, interference with eating, and maximal incisal opening. Paired t tests and comparison analyses were used to assess outcomes. RESULTS There was statistically significant improvement in pain level (P = .0001), jaw function (P = .0001), and incisal opening (P = .0001). Although there were complications necessitating the removal of 14 of 442 implants (3.2%), there were no device-related mechanical failures. CONCLUSIONS The clinical study presented supports the conclusion that a stock TMJ alloplastic replacement, based on sound orthopedic and biomedical principles, is a safe and efficacious option when alloplastic reconstruction of the TMJ is indicated.

Mortised genioplasty in the treatment of obstructive sleep apnea: an historical perspective and modification of design.

We describe a modified technique for mortised genioglossus advancement for treating obstructive sleep apnea and review the history of osteotomies in this region. This new osteotomy technique allows for greater soft tissue advancement of the hypopharyngeal region. Anatomical data from a previous study were used to evaluate the dimensions of the anterior mandible and design an osteotomy that overcomes shortcomings of previous designs. These anatomic measurements enabled us to estimate the size and formulate a design utilized in the anterior mandible for the treatment of obstructive sleep apnea. We believe this design offers the greatest amount of muscular advancement by including genioglossus, geniohyoid, digastric, and mylohyoid. This advancement results in increasing the posterior airway space by volumetric expansion. Custom-designed fixation was utilized to increase stability laterally and decrease the risk of mandibular fracture. The design should be a significant aid in reconstruction of the hypopharyngeal airway in patients with obstructive sleep apnea.

Posttraumatic Temporomandibular Joint Disorders

The temporomandibular joint (TMJ) has many essential functions. None of its components are exempt from injury. Facial asymmetry, malocclusion, disturbances in growth, osteoarthritis, and ankylosis can manifest as complications from trauma to the TMJ. The goals of initial treatment include achievement of pretraumatic function, restoration of facial symmetry, and resolution of pain. These same objectives hold true for late repairs and reconstruction of the TMJ apparatus. Treatment is demanding, and with opposing approaches. The following article explores various treatment options for problems presenting as a result of a history of trauma to the TMJ.

Beta-adrenergic Blocking Agents and Dental Vasoconstrictors

A clinically significant interaction between epinephrine or levonordefrin with nonselective beta-adrenergic blocking agents, although apparently rare in the dental setting, is potentially serious and can lead to significant hypertension with a concomitant reflex bradycardia. Based on the results of epinephrine infusion studies, the severity of the interaction seems dose related; small epinephrine doses cause less of a pressor response than larger doses. The interaction can be seen after intraoral submucosal injections but is generally of a smaller magnitude, at least with only 1 or 2 cartridges of lidocaine plus 1:100,000 epinephrine. However as demonstrated by 1 case report, some individuals are hypersensitive to this interaction. Inadvertent intravascular injections of local anesthetic plus vasoconstrictor and the use of high doses of vasoconstrictor are likely to result in a more pronounced response. Patients with significant cardiovascular disease may be especially vulnerable to the most serious sequelae resulting from the pressor reactions of the drug combination.

Lack of Methemoglobin Elevations After Topical Applications of Benzocaine Alone or Benzocaine Plus Tetracaine to the Oral Mucosa

PURPOSE This study evaluated changes in methemoglobin and oxygen saturation concentrations after the administration of recommended doses of 14% benzocaine alone or 14% benzocaine combined with 2% tetracaine. METHODS American Society of Anesthesiology class 1 and 2 subjects (n = 40) were enrolled in this modified crossover study. Subjects were administered 0.2 mL of 14% benzocaine alone, 0.2 mL of 14% benzocaine plus 2% tetracaine, or 0.4 mL of 14% benzocaine plus 0.2% benzocaine to their cheek mucosa. Venous blood (5 mL) was drawn from the antecubital fossa before and 60 minutes after drug application for methemoglobin analyses. Oxygen saturation was also recorded via pulse oximetry at baseline and every 10 minutes through 60 minutes after drug application. FINDINGS Methemoglobin and oxygen saturation levels did not change from baseline after the administration of benzocaine alone or when combined with tetracaine. IMPLICATIONS Recommended doses of benzocaine or benzocaine combined with tetracaine when applied to the cheek mucosa do not induce even clinically insignificant elevations in methemoglobin levels. Metered dosing, such as that used in this study, can help avoid this overdose phenomena with these drugs. ClinicalTrials.gov identifier: NCT02908620.

Retrospective Study of Facial Nerve Function Following Temporomandibular Joint Arthroplasty Using the Endaural Approach

The aim of this retrospective case–control study is to evaluate the incidence of facial nerve injury associated with temporomandibular joint (TMJ) arthroplasty using the endaural approach for the treatment of TMJ pathology. The sample consisted of 36 consecutive patients who underwent TMJ arthroplasty. A total of 39 approaches were performed through an endaural incision. Patients undergoing total joint replacement and/or with preexisting facial nerve dysfunction were excluded from the study. Five patients were lost to follow-up and were excluded from the study. Facial nerve function of all patients was clinically evaluated by resident physicians preoperatively, postoperatively, and at follow-up appointments. Facial nerve injury was determined to have occurred if the patient was unable to raise the eyebrow or wrinkle the forehead (temporalis branch), completely close the eyelids (zygomatic branch), or frown (marginal mandibular branch). Twenty-one of the 36 patients or 22 of the 39 approaches showed signs of facial nerve dysfunction following TMJ arthroplasty. This included 12 of the 21 patients who had undergone previous TMJ surgery. The most common facial nerve branch injured was the temporal branch, which was dysfunctional in all patients either as the only branch injured or in combination with other branches. By the 18th postoperative month, normal function had returned in 19 of the 22 TMJ approaches. Three of the 22 TMJ approaches resulted in persistent signs of facial nerve weakness 6 months after the surgery. This epidemiological study revealed a low incidence of permanent facial nerve dysfunction. A high incidence of temporary facial nerve dysfunction was seen with TMJ arthroplasty using the endaural approach. Current literature reveals that the incidence of facial nerve injury associated with open TMJ surgery ranges from 12.5 to 32%. The temporal branch of the facial nerve was most commonly affected, followed by 4 of the 22 approaches with temporary zygomatic branch weakness. Having undergone previous TMJ surgery did not increase the incidence of facial nerve injury using the endaural approach. This information is important for patients and surgeons in the postoperative period, as a majority of patients will experience recovery of nerve function.