The effect of rim mandibulectomy configuration and residual segment size on postoperative fracture risk: an in vitro study.

PURPOSE: This study evaluated the effect that size and shape of rim mandibulectomy has on residual mandibular strength and resistance to fracture, with the ultimate goal of improving the use of this technique and establishing a threshold for the application of prophylactic internal fixation. MATERIALS AND METHODS: Ten partially dentate dry human mandibles were mounted in a manner replicating the pterygomasseteric musculature. Unilateral midbody serial rim excisions of increasing size were completed in both a curvilinear and right-angled fashion, and physiologic forces were gradually applied to a level of residual segment fracture. Dimensional measurements were taken of the specimens before and after fracture to understand which factors contributed to failure. RESULTS: On average, a curvilinear excision configuration resisted higher occlusal forces with a smaller residual segment than did the right-angled excision configuration. A residual inferior border thickness of less than 9 mm could not predictably withstand force application within the limits of the experimental model. CONCLUSION: These data support the use of a curvilinear excision configuration for rim mandibulectomies. Reproducibility of the location of the residual segment failure and other consistent residual segment dimensional information have implications regarding the limitations of this technique, beyond which the use of adjunctive support in the form of maxillomandibular fixation or prophylactic internal fixation may be indicated.

Strain gauge analysis of the frontozygomatic region of the zygomatic complex.

PURPOSE: This study evaluates the biomechanical consequences of physiologic forces acting on the frontozygomatic suture region, with the ultimate goal of defining appropriate fixation techniques and improving the surgical management of this complex anatomic region. MATERIALS AND METHODS: Single foil strain gauges were bonded to the cortical surface of the frontal process of the zygoma in 13 subadult Cercopithecus africanus. Subdermal electrodes were used to induce tetanic contractions of the jaw elevator muscles, and bite force was measured using a twin-beam bite force transducer placed between the teeth. Microstrain was simultaneously measured and recorded. RESULTS: Tensile strains predominated in the region of the frontal process of the zygoma, with balancing side strains twice as large as working side strains; incisal strains were intermediate. CONCLUSIONS: The tensile strains observed in the frontozygomatic region contradict the concept of this area as a "stress riser" for compressive occlusal forces, and supports the use of compression plate osteosynthesis for improved stabilization of fractures in this region.

Ultrasound detection of abscesses in the temporomandibular joint following surgical reconstruction.

The purpose of this investigation is to report the technique and assess the utility of ultrasound diagnosis of abscess in the postoperative temporomandibular joint (TMJ). Fourteen patients had 18 ultrasound examinations of the postoperative temporomandibular joint (TMJ) to detect a possible abscess. Ultrasound examinations were performed with either a 5-MHz linear array and/or a 7.5-MHz sector probe following placement of implants (16) and autogenous costochondral grafts (2). The TMJ was scanned in both coronal and axial planes. In 14 examinations, an abscess was not detected; there were no false-negatives. Soft-tissue edema was found in 1 of these 14 examinations; at surgery, there was no abscess. Four examinations were positive for an abscess; 3 of these were confirmed at surgery. One examination was false-positive. We conclude that ultrasonography can detect an abscess in the symptomatic postoperative TMJ. A negative examination is reliable.

Temporomandibular joint arthroscopy: a 6-year multicenter retrospective study of 4,831 joints.

Four health outcomes (range of motion, pain, diet, and disability) were measured in six diagnostic categories (internal derangement with closed lock, internal derangement with painful click, osteoarthritis, hypermobility, fibrous ankylosis, and arthralgia) in a 6-year retrospective multicenter study of 4,831 temporomandibular joints having undergone arthroscopic surgery. After arthroscopic surgery, 91.6% of all patients had good or excellent motion; 91.3% had good or excellent pain reduction; 90.6% had good or excellent ability to maintain a normal diet; and 92% had a good or excellent reduction in disability. These health outcomes compare favorably with all other known treatments for these conditions. Also, the surgical technique was relatively free of complications (4.4%).

Early response of canine temporomandibular joint tissues to arthroscopically guided neodymium: YAG laser wounds.

A neodymium yttrium aluminum garnet (Nd:YAG) laser inserted through an operating arthroscope was used to introduce applied energy to synovial tissues, articular discs, and bone in the temporomandibular joint of mongrel dogs. Arthroscopic inspection of the wounds was performed at 1 and 2 weeks postoperatively. The animals were killed and the temporomandibular joints were examined grossly and histologically to determine the extent of injury and healing. The results show that laser wounds of bone and articular disc undergo no repair, whereas laser wounds of synovium show rapid repair. Laser damage to condylar marrow under an articular disc wound was unexpectedly found.

The morbidity associated with fifty maxillary fractures treated by closed reduction.

Fifty patients with maxillary fractures treated by closed reduction over an 85 month period at a Level I trauma center were reviewed. Thirty patients (60%) experienced forty-one midfacial complications. The most frequent problems were infraorbital nerve paresthesia (12), enophthalmus (5), septal deviation (3), and altered vision (3). No relationship could be established between complications and age, sex, cause of injury, or the method of suspension used. Most complications were related to concomitant injury or the concurrent management of fractures of other facial bones. Only eight problems (16%) were directly attributed to the closed reduction of maxillary fractures. Patients treated by closed reduction and maxillomandibular fixation without suspension experienced no surgical complications.

The third molar as a cause of deep space infections.

An 81-month review of patients with deep space infections attributed to third molars requiring hospital admission is presented. Thirty-one patients were identified, with males predominating 2:1 and mandibular third molars as an etiology predominating 15:1. All patients were aged 23 years or older. Most patients identified (24) had one or more medical problems or other risk factors, the most frequent of which was smoking (18). All patients developing postoperative infections (9) had complete or partial bone impactions and a preoperative diagnosis of pericoronitis.

An epidemiologic and anatomic survey of odontogenic infections.

An 81-month review of patients with infections of odontogenic origin admitted to the oral and maxillofacial surgery service at a county hospital and teaching facility in northeast Ohio is presented. Age, sex, race, etiology, pathogens isolated, admission temperature, and admission white blood cell count were identified and related to the anatomic space(s) encountered. Multispace and single-space infections occurred with equal distribution. In both the multispace and single-space infections, the submandibular and buccal spaces were most frequently involved. Males were affected with single-space infections twice as often as females. An equal distribution among sexes was found in multispace infections. The most common age range for all infections was 25 to 30 years. alpha-Hemolytic streptococci, Bacteroides melaninogenicus, and beta-hemolytic streptococci were the most frequently isolated pathogens. Third molars were the prevalent cause in both multispace and single-space infections that required hospital admission.

Management of the oral and maxillofacial surgery patient on anabolic steroids.

Recent Food and Drug Administration estimates indicate that the anabolic steroid market has reached the $100 million level. Although the news media report steroid-related deaths, there is little in the medical literature communicating the clinical implications concerning these drugs. Electrolyte disturbances, coagulopathies, hypertension, and dysrhythmias are a few of the potential side effects. The pharmacology and pathophysiology of anabolic steroids are presented with a discussion of the anesthetic and surgical concerns for the patient undergoing oral and maxillofacial surgery.

Care of the asthmatic oral and maxillofacial surgery patient.

It is estimated that asthma affects 6 to 9 million people in the United States. The nature of this disease makes it a special concern to the oral and maxillofacial surgeon. Appropriate management of the asthmatic patient with regard to anesthesia and surgical procedures of the oral and maxillofacial region is discussed.

Reviewing the unicystic ameloblastoma: report of two cases.

Classification of ameloblastoma into solid, multicystic, unicystic, and peripheral types based on clinical appearance and effects has gained recent recognition. The unicystic ameloblastoma is a less encountered variant of the ameloblastoma. It appears more frequently in the second or third decade with no sexual or racial predilection. It is almost exclusively encountered asymptomatically in the posterior mandible. The following report of two cases discusses the pathophysiology, demographics, histology, and prognosis of the unicystic ameloblastoma.

Estimation of maxillary alveolar cleft volume by three-dimensional CT.

Reconstruction of cleft lip and palate deformities is a challenging problem involving a variety of the subspecialties of surgery, dentistry, and medicine as well as radiology. This paper outlines the contribution of three-dimensional CT to preoperative treatment planning for bone grafting of a maxillary cleft alveolus.

An epidemiologic survey of facial fractures and concomitant injuries.

A 5-year review of facial fractures and concomitant injuries at a level 1 trauma center is presented. The anatomic location of the facial fractures, age and sex of the patients, cause of injury, and associated systems injuries are presented. The majority of facial fractures were found in males; the most prevalent age range was 16 to 30 years. Mandible fractures outranked zygomatic and maxillary fractures (6:2:1). Assaults and motor vehicle accidents were the most frequent causes of facial fractures, and lacerations followed by neurologic and orthopedic injury were the most frequently encountered concomitant injuries. Motor vehicle accidents were the most frequent cause of associated injury.

Dermal grafts of the temporomandibular joint: postoperative appearance on MR images.

Complications may follow meniscectomy and placement of an allogenic implant in temporomandibular joint (TMJ) dysfunction. To characterize the anatomy of autogenous dermal grafts for repair and repositioning of the meniscus, the authors performed T1-weighted magnetic resonance (MR) imaging of 20 TMJs in 10 patients 6-23 months after surgery that was considered successful. MR imaging did not enable detection of the dermal grafts. Comparison of preoperative and postoperative MR images revealed little, if any, change in meniscal position. MR images of 20 menisci revealed anterior displacement (n = 11), normal position (n = 4), focal areas of increased signal intensity (n = 4), fragmentation (n = 2), and suboptimal visualization (n = 5). MR images of 20 condyles revealed normal features (n = 11), erosions (n = 2), early avascular necrosis (AVN) or subchondral cysts (n = 2), AVN (n = 3), an osteophyte (n = 1), and loss of bone (n = 2). One TMJ demonstrated increased soft tissue in the bilaminar zone.

Treatment of oral squamous cell carcinoma with simultaneous chemotherapy and radiation: results and surgical implications.

Thirty-seven patients with oral squamous cell carcinoma, many with advanced disease, were treated initially with a protocol using simultaneous intravenous 5-fluorouracil (5-FU) cis-platinum, and radiation. Twenty-two patients (62%) experienced complete remission after one cycle of therapy. Fifteen patients (38%) demonstrated an incomplete response; surgical resection was possible in 14 of these 15 patients. A second cycle of chemoradiotherapy was administered to all 37 patients. After this treatment resection is possible for some patients who are initially inoperable, and surgery is necessary only for those patients (38%) who show an incomplete remission after the first cycle of therapy and for those who present initially with bony invasion. Furthermore, the treatment of cervical nodes and intraoral disease may be divorced and the extent of surgery may be reduced for many patients. A 5-year survival of 76% is predicted for this group of patients. The described protocol shows promise for treatment of oral squamous cell carcinoma.

Diagnosis and treatment of the retropharyngeal abscess in adults.

While the retropharyngeal space abscess is an extremely rare entity that may arise from odontogenic infections, its potential complications may be fatal. When infection of the retropharyngeal space occurs, urgent surgical and antibiotic therapy is required. A review of the anatomy, symptoms, treatment, diagnostic methods and complications is provided. As well, the successful treatment of a multispace odontogenic infection is discussed as a reminder that the retropharyngeal abscess does exist.