A retrospective evaluation of rigid fixation in orthognathic surgery using a biodegradable self-reinforced (70L:30DL) polylactide.

OBJECTIVE: This study was designed to evaluate clinical and radiological evidence of osteotomy site healing in orthognathic surgery after rigid fixation using a biodegradable plating system. STUDY DESIGN: A follow up of 30 patients who underwent orthognathic surgery using a biodegradable self-reinforced (70L:30DL) polylactide plating system was presented. The follow-up schedule for all patients consisted of regular appointments at 1-180 days after surgery. Clinical evaluation involved notation of any abnormal swelling, infection, discoloration, or discharge at the osteotomy sites. Stability was evaluated by manual palpation. For radiographic evaluation, panoramic radiographs were taken immediately after surgery, and again at 7-180 days. The radiographs were analyzed for any visual changes in osteotomy fragments, resorptive changes in osteotomy fragments, callus formation, and union of the osteotomy segments. RESULTS: No clinical complications and no radiological changes in the osteotomy sites were observed. Regarding the clinical usefulness of the biodegradable fixation system, fixation at the time of operation was considered as excellent in all 30 cases. CONCLUSIONS: The conclusions of this study were that self-reinforced (70L:30DL) polylactide was considered to be comparable to other forms of rigid internal fixation for orthognathic surgery.

Long-term evaluation of arthroscopic discectomy of the temporomandibular joint using the Holmium YAG laser.

PURPOSE: The goal of this study was to evaluate the clinical results with arthroscopic discectomy using a Holmium YAG laser for treatment of patients with pain and dysfunction and large disc perforations resulting by advanced internal derangement. PATIENTS AND METHODS: The subjects comprised 30 patients (38 joints) who underwent arthroscopic discectomy with Holmium YAG laser. All patients had chronic pain, restricted range of motion, and a diagnosis of disc perforation (Wilkes stage IV to V of internal derangement). All patients had not responded to conventional nonsurgical treatment (eg, appliance therapy, nonsteroidal anti-inflammatory drugs, physical therapy) or previous temporomandibular joint (TMJ) arthroscopy. All patients filled out a questionnaire preoperatively and postoperatively for assessment of their signs and symptoms. The questionnaire consisted of a visual analog scale (VAS) with items on pain and diet. RESULTS: The overall success rate for arthroscopy discectomy using a Holmium YAG laser was 93.33% (28 of 30 patients) in a mean follow-up of 31.7 months. No complications were observed in this study. Maximal interincisal opening improved from a mean of 25.40 to 39.96 mm after 18 months or more from surgery. The subjective data elicited from VAS scores showed a significant improvement in pain score, in interference of pain with normal diet, and effect of pain on life in general. All preoperative scores were significantly different from postoperative scores (P <.05). CONCLUSIONS: On the basis of this follow-up study, arthroscopic discectomy for treatment of large disc perforations seems to provide an effective treatment for TMJ pain and dysfunction, decreasing the pain and improving the range of motion.

Opossum adrenal medulla: II. Differentiation of the chromaffin cell.

The ultrastructure of the opossum adrenal medulla was examined in its postnatal development. Maturation of chromaffin cells and genesis of chromaffin vesicles were of particular interest. The primitive sympathetic cell was seen to contain few organelles with no apparent polarity. Initial pheochromoblasts contained more organelles with some polarity. Endoplasmic reticulum and the Golgi complex increased as the pheochromoblasts matured, which suggested increased synthetic activity. Structures resembling Golgi/endoplasmic reticulum/lysosome (GERL) systems were seen in the pheochromoblasts. It is suggested that some of the components of the chromaffin vesicle may be processed by the GERL while others come directly through the Golgi complex. It is stressed that the developing pheochromoblast in the opossum presents an interesting model in which to study the genesis of the chromaffin vesicle.

Opossum adrenal medulla: I. Postnatal development and normal anatomy.

The anatomy and histology of the adrenal gland in the adult opossum were found to be typical for mammals. The development of the adrenal medulla was also found to follow the typical mammalian pattern. Primitive sympathetic cells were found in both intra- and extra-adrenal locations in the newborn at a time when chromaffin precursor cells were migrating to the adrenal anlage. Pheochromoblasts first appeared within the forming medulla where at a later stage chromaffin cells could be observed forming columns of cells between adjacent sinusoids. Unlike in other mammals, much of this development takes place postnatally when the neonate is in the mother's marsupium. The value of the developing opossum adrenal medulla as an experimental model is stressed, since a significant amount of development takes place in an environment that is accessible to experimental manipulation.

Perfusion fixation of the newborn opossum: equipment and techniques.

A 30-gauge cannula was used to perfuse fixative through the fragile heart of a newborn opossum. The cannula was gently maneuvered into the heart and held in place with a specially designed manipulator. The flow rate of the fixative was regulated with an infusion set connected to the cannula.