Characterization of a biomaterial with cartilage-like properties expressing type X collagen generated in vitro using neonatal porcine articular and growth plate chondrocytes.

OBJECTIVE: The availability of cartilage with or without the potential to ossify and suitable for surgical restoration and resurfacing of joints is an important clinical problem in arthritis-related pathology, trauma and reconstructive surgery. Here, we designed experiments to generate a biomaterial with cartilage-like properties by culturing neonatal porcine articular and growth plate chondrocytes on a hydrogel substrate and to examine the biochemical and histological characteristics of the resulting tissue. DESIGN: Neonatal porcine epiphyseal and growth plate chondrocytes were cultured on poly(2-hydroxyethyl methacrylate) (polyHEMA)-coated dishes to prevent their adherence to plastic. We previously described that this procedure allows the maintenance of the chondrocyte-specific phenotype for > or = 8 months. Chondrocytes were isolated by successive enzymatic digestions and cultured at high density (>2.0 x 10(7) cells/ml) in DMEM with 10% FBS, 50 microg/ml ascorbic acid, glutamine, vitamins, and antibiotics for up to 10 weeks on 60 mm plastic culture dishes coated with polyHEMA. The tissues produced during culture were studied histologically and biochemically and were examined for cellular proliferation employing(3)H-thymidine incorporation and for their collagen production employing biosynthetic labeling with(14)C-proline and Western blot with specific antibodies. The expression of relevant collagen genes was examined employing RT-PCR. RESULTS: Within 24 h of culture, isolated chondrocytes organized into well-formed clusters and in 2 weeks formed structures with gross appearance and consistency similar to those of natural cartilage. The wet weight of the tissue formed in vitro increased six-fold during the 10-week period of study. Cell proliferation measured by the incorporation of(3)H-thymidine increased during the first 3 weeks and reached a plateau in subsequent weeks. Histological examination showed that the cultures contained rounded chondrocytes embedded in an abundant cartilaginous extracellular matrix. The cartilage formed contained large amounts of collagen and sulfated proteoglycans as examined by staining with Masson's Trichrome and Alcian blue, respectively. Deposition of calcium in the deeper layers of the tissue was demonstrated with the von Kossa stain. Western analyses with specific antibodies showed that type II collagen was present from the first week and progressively increased in the cultures, whereas type X collagen was first detected at 4 weeks and increased with length of culture. When chondrocytes isolated from the growth plate were included, small amounts of type I collagen were detected in the medium of cultured biomaterial as expected. Type III collagen was not detected by Western blot over the 10-week period. High levels of type II and type X collagen gene expression were demonstrated by RT-PCR. CONCLUSION: These studies demonstrate the production in vitro of cartilage-like tissue with similar morphological, histochemical and biochemical characteristics to those of natural growth plate cartilage. The cartilage generated in vitro has the potential to be used in reconstructive surgery and in joint resurfacing and restoration of skeletal defects.

Predictors of outcome for uvulopalatopharyngoplasty.

The objective of this study was to assess the value of preoperative fiberoptic nasopharyngoscopy with the Müller maneuver (FNMM) and cephalometric radiography in predicting response to uvulopalatopharyngoplasty (UPPP) in patients with obstructive sleep apnea syndrome. Fifty-three such patients having significant obstruction at the soft palatal level and variable degrees of obstruction at the base-of-tongue level underwent both diagnostic procedures before UPPP. Outcome was assessed by the apnea-plus-hypopnea index (AHI) as determined by polysomnography, which was performed before and after surgery. As a group, patients exhibited a significant 10-point reduction in AHI (46.5 to 36.7). However, 17 (32.1%) were judged to be responders as defined by a reduction of the AHI by an increment of 50% or greater with respect to baseline. Of all the cephalometric variables assessed, soft palate length was the only one that differed between responders and nonresponders (45.5 mm versus 42.6 mm, respectively). However, this difference only approached significance (P = .067). Similarly, FNMM results did not discriminate between responders and nonresponders. These results indicate that preoperative cephalometric radiography and FNMM cannot be reliably used to enhance surgical success.

Elusive "stuck" disk in the temporomandibular joint: diagnosis with MR imaging.

PURPOSE: To determine the incidence of a "stuck" disk and its importance in the overall scheme of internal derangement. MATERIALS AND METHODS: Magnetic resonance (MR) images of 212 temporomandibular joints (TMJs) in 106 symptomatic patients were obtained and reviewed. Image analysis included assessment of disk position; disk mobility; and degree of condylar translation, with or without disk recapture in joints with displaced disks. RESULTS: Of the 127 joints with disks in a normal position, 94 had mobile disks and 23 had stuck disks. Ten joints revealed no condylar translation, which precluded assessment of disk mobility. Of 85 joints with displaced disks, 67 joints showed mobility, with recapture in 25 and no recapture in 42. Significant correlation existed between disk mobility and degree of condylar translation (P < .001). CONCLUSION: The TMJ disk may be stuck in a normal or displaced position and limits the normal degree of condylar translation, leading to restricted jaw opening. Recognition of a stuck TMJ disk could alter patient care.

Microscrew and microplate systems for select osteotomies in orthognathic surgery.

The use of the semirigid screw and plate systems is common place in orthognathic surgery by many oral and maxillofacial surgeons. The size of the screw and plate systems used is commonly designated as mini or osteotomy size. Screw diameter is generally 2.0 mm and plate thickness range is 0.8 mm to 1.2 mm. The systems available perform very well for the majority of osteotomies. There are circumstances when these mini systems are not appropriate. Recently developed microsystems have been applied by us in selected cases of orthognathic surgery. The smallest of the microsystem screws are 0.8 mm diameter and all are available in 2, 3, 4, 5, 6, 8 mm lengths. Some microplates are 0.3 mm thick and available in various shapes including a straight chain. The resultant profile thickness of screw plus plate system becomes 0.8 mm.

Nondiscogenic causes of temporomandibular joint pain.

Magnetic resonance imaging of the temporomandibular joint is a topic of recent interest and has gained widespread use for the assessment of internal derangement and other temporomandibular joint-related symptoms. In this article the authors present six proven cases of pathologic abnormalities of the temporomandibular joint region that may clinically mimic internal derangement. These cases demonstrate the importance of the monitoring of studies by a radiologist and also the utility of computed tomography as an adjunctive modality. Magnetic resonance imaging and computed tomography are often complimentary in diagnosing etiologies that may mimic internal derangement. Because abnormalities other than internal derangement are often encountered during the use of magnetic resonance imaging, it is essential for the radiologist to assume an active role in monitoring such cases.

A unique indexing splint for use in combined Le Fort and nasal injuries to avoid tracheostomy.

Midface fractures with associated displaced and/or comminuted nasal fractures can require tracheostomy for a general anesthetic airway if these fractures are to be reduced simultaneously. We describe a unique indexing splint that allows oral intubation yet also allows simultaneous reduction of midface and nasal fractures under one anesthetic. Furthermore, tracheostomy with its potential complications is avoided. The case report illustrates the technique, and alternative treatments for these injuries are discussed.

Temporomandibular joint dysfunction: correlation of MR imaging, arthrography, and arthroscopy.

This prospective study correlated the results of magnetic resonance (MR) imaging, arthrography, and arthroscopy in 27 patients with clinically suspected temporomandibular joint (TMJ) dysfunction. Open surgical confirmation was available in 12 TMJs. The variables assessed with each modality were disk position and morphology, disk perforation, joint adhesions, and degenerative joint disease. MR imaging was superior to dual joint arthrography with arthrotomography in delineation of the disk position. MR imaging accurately demonstrated the disk position in 11 joints (92%); arthrography was accurate in nine of the 12 joints (75%) with surgically confirmed dysfunction. Disk perforations and joint adhesions were not demonstrated with MR imaging. Arthroscopy was superior to arthrography and MR imaging in the detection of disk perforations, joint adhesions, and early degenerative changes along the articular eminence and glenoid fossa. The authors believe MR imaging should constitute the first line of imaging because it provides accurate information about disk position in a noninvasive manner. In most cases, information obtained with MR imaging is adequate in deciding whether to institute conservative or surgical management; in difficult cases, triple correlation may be needed.

Posterior airway changes associated with mandibular advancement surgery: implications for patients with obstructive sleep apnea.

Obstructive sleep apnea syndrome is caused by loss of tone in the pharyngeal muscles. Bilateral sagittal ramus osteotomy has occasionally been used to treat this syndrome. To determine if postsurgical changes in posterior airway space are predictable, the posterior airway space in 25 patients who did not have obstructive sleep apnea was measured before and after surgery. Analysis revealed that the posterior airway space usually increased after advancement of the mandible, but the changes were varied. Therefore, the procedure may be helpful in some patients with obstructive sleep apnea syndrome and may obviate the need for tracheostomy, but success cannot be guaranteed.

Arthroscopy of the temporomandibular joint.

Arthroscopy is a technique that allows direct visual examination of the internal surfaces of the joint. In the past decade, arthroscopy has become a major diagnostic and therapeutic tool in the treatment of articular disorders of the knee. The purpose of this report is to present a comprehensive overview of temporomandibular joint (TMJ) arthroscopy in order to familiarize the practitioner with this adjunct to temporomandibular disorder diagnosis and treatment.

Induced hypotension with labetalol for orthognathic surgery.

Induced hypotension is an accepted technique for reducing blood loss in various surgical procedures. This study evaluates the effectiveness of labetalol in producing controlled reduction in mean arterial pressure during orthognathic surgery. The potential advantages of this technique are ease of administration, decreased pulmonary shunting, and absence of tachycardia or rebound hypertension compared to other commonly used agents.

Temporal screw suspension for complicated midface fractures.

A technique that uses a temporal screw for skeletal suspension has been described. This alternative is useful when other methods cannot be used because of avulsion or comminution of routinely used skeletal fixation points.

Garre's osteomyelitis: report of case associated with a granuloma.

This article reports a case of Garre's osteo with an atypical cause, and a differential diagnosis of other conditions that appear with similar clinical and radiographic findings is included.

Reflex sympathetic dystrophy syndrome. Case report with a review of the literature.

A case of reflex sympathetic dystrophy syndrome (RSDS) is presented in which the condition was exacerbated after the excision of impacted teeth. A review of the English language literature describes manifestations, distribution, etiology, pathogenesis, histology, and diagnosis of RSDS. Treatment modalities are reviewed, and recommendations for the management of the patient with a history of RSDS are detailed.

Nitroglycerin-controlled circulation in orthognathic surgery.

Significant blood loss is a potential complication of maxillary osteotomies and maxillary and mandibular osteotomies. Controlling circulation by lowering blood pressure is a technique that has been used successfully to avoid this problem. Of the various agents available, nitroglycerin was chosen because of its known beneficial cardiovascular effects and its lack of toxicity as compared with sodium nitroprusside. Nine patients undergoing either maxillary or maxillary/mandibular osteotomies were anesthetized with halothane, N2O, O2, and supplemental doses of a muscle relaxant and narcotic. Nitroglycerin was used to lower mean arterial pressure during periods of potential increased blood loss. Estimated blood loss was 439 +/- 1.19 ml. The hemoglobin and hematocrit fell slightly from 13.8 +/- 1.74 g/dl and 41.2 +/- 5.11% to 12.04 +/- 1.8 g/dl and 35.6 +/- 4.9%. Attenuation of the pulmonary hypoxic vasoconstriction reflex was also seen, as was evidenced by a decrease in PaO2 after nitroglycerin administration. It was concluded that nitroglycerin is a safe and efficacious agent for controlled circulation during maxillary osteotomy surgery.