Reconstruction of mandibular symphyseal defects by trifocal distraction osteogenesis: an experimental study in Rhesus.

Mandibular symphyseal defects caused by tumor surgery, trauma, or congenital misshape can produce maxillofacial deformity and functional handicap. Recently, the technique of distraction osteogenesis has become a valuable reconstructive method for craniofacial bone defects. Four adult rhesus monkeys were used in this study. The anterior mandibulectomy (ranged from canine to canine) was performed, and bilateral transport segments (ranged from first premolar to first molar) were created. Custom-made multiplanar distractors were applied for the reconstruction of the monkeys' artificial mandibular symphyseal defects by trifocal distraction osteogenesis. After a delay period of 7 days, the bilateral transport discs were distracted forward and inward simultaneously. Serial X-ray and three-dimensional CT films were taken within the experimental period. Two monkeys were sacrificed at 8 and 16 weeks, respectively, after the completion of distraction. The distracted calluses and united areas between bilateral transport discs were harvested and processed for histological examination. The mandibular symphyseal defects in all animals were repaired successfully and the anterior mandibular contours were similar to the normal ones. Perfect bone regeneration in the distraction gaps was found, and fibro-bony union between the bilateral transport segments was observed in the midline region at 16 weeks after the end of distraction. The success of distraction osteogenesis for repair of mandibular symphseal defects in monkeys by this distractor may provide an alternative method to reconstruct the anterior part of mandible.

Abundant expression of myosin heavy-chain IIB RNA in a subset of human masseter muscle fibres.

Type IIB fast fibres are typically demonstrated in human skeletal muscle by histochemical staining for the ATPase activity of myosin heavy-chain (MyHC) isoforms. However, the monoclonal antibody specific for the mammalian IIB isoform does not detect MyHC IIB protein in man and MyHC IIX RNA is found in histochemically identified IIB fibres, suggesting that the IIB protein isoform may not be present in man; if this is not so, jaw-closing muscles, which express a diversity of isoforms, are likely candidates for their presence. ATPase histochemistry, immunohistochemistry polyacrylamide gel electrophoresis and in situ hybridization, which included a MyHC IIB-specific mRNA riboprobe, were used to compare the composition and RNA expression of MyHC isoforms in a human jaw-closing muscle, the masseter, an upper limb muscle, the triceps, an abdominal muscle, the external oblique, and a lower limb muscle, the gastrocnemius. The external oblique contained a mixture of histochemically defined type I, IIA and IIB fibres distributed in a mosaic pattern, while the triceps and gastrocnemius contained only type I and IIA fibres. Typical of limb muscle fibres, the MyHC I-specific mRNA probes hybridized with histochemically defined type I fibres, the IIA-specific probes with type IIA fibres and the IIX-specific probes with type IIB fibres. The MyHC IIB mRNA probe hybridized only with a few histochemically defined type I fibres in the sample from the external oblique; in addition to this IIB message, these fibres also expressed RNAs for MyHC I, IIA and IIX. MyHC IIB RNA was abundantly expressed in histochemical and immunohistochemical type IIA fibres of the masseter, together with transcripts for IIA and in some cases IIX. No MyHC IIB protein was detected in fibres and extracts of either the external oblique or masseter by immunohistochemistry, immunoblotting and electrophoresis. Thus, IIB RNA, but not protein, was found in the fibres of two different human skeletal muscles. It is believed this is the first report of the substantial expression of IIB mRNA in man as demonstrated in a subset of masseter fibres, but rarely in limb muscle, and in only a few fibres of the external oblique. These findings provide further evidence for the complexity of myosin gene expression, especially in jaw-closing muscles.

Esthetic facial surgery for women.

Women of all ages are increasingly seeking facial cosmetic surgery for personal and professional reasons. A wide array of surgical procedures is available to address each woman's specific request. Esthetic facial surgery and cosmetic dentistry may complement each other to provide dramatic results.

Ergonomics investigation of retail ice cream operations.

A comprehensive ergonomics evaluation of retail ice cream shops, including field and laboratory data collection, was conducted using a human:workplace model approach to ergonomics practice. The goal of the evaluation was to provide recommendations to enhance the health, safety, and productivity of shop employees. Active and passive surveillance and facility walk-throughs were used to guide the selection of analyses. A primary focus of the investigation was quantifying the task demands of scooping ice cream, which have not been documented in the literature. This goal was accomplished through the use of a custom-designed instrumented ice cream scoop. Data were collected at an ice cream shop under typical conditions, while the laboratory experiment investigated task demands of ice cream scooping over a range of realistic temperatures. Manual materials handling task analyses and anthropometric evaluations comprised the majority of other analyses performed. Recommendations are presented that are applicable to the operation of retail ice cream shops that serve hard (i.e., scooped) ice cream.

Subjective and objective assessment of the temporalis myofascial flap in previously operated temporomandibular joints.

PURPOSE: This study evaluated the subjective and objective findings in patients who had undergone temporomandibular joint (TMJ) reconstruction with a temporalis myofascial flap. All joints had previously been reconstructed with alloplastic, allogeneic, or autogenous material. PATIENTS AND METHODS: Twenty-three consecutive patients who underwent 28 temporalis myofascial flap procedures were assessed subjectively and objectively preoperatively and at an average of 36 months postoperatively. Panoramic radiographs, magnetic resonance imaging (MRI), or coronal computed axial tomography scans (CT scans) were performed on all patients preoperatively to evaluate for joint disease. A visual analog scale (VAS) was used to assess pain preoperatively and postoperatively. Patients also reported their use of pain medication, ability to function, diet, complications, and overall satisfaction. Preoperative and postoperative objective assessment consisted of an evaluation of range of motion, deviation on opening, joint noise on function, and cosmesis. RESULTS: On preoperative radiographic examination, 24 of 28 joints showed signs of bony degeneration, including cortical erosion, condylar flattening, and joint space alterations. Four joints showed evidence of ankylosis. The average preoperative maximal interincisal opening (MIO) was 23.7 mm, and the postoperative average was 32.3 mm (P<.05). Preoperatively, all patients displayed one or more objective clinical signs of joint disease such as joint noise on function, deviation on opening, limited mouth opening (less than 20 mm), or limited excursions (less than 2 mm). Postoperatively, 65% displayed one or more of these signs, a significant reduction (P<.05). Preoperatively, the average pain score was 8.2 on the VAS, and postoperatively the average pain score was 3.4 (P<.0005). Fifteen patients used less pain medication postoperatively, 7 used the same amount, and 1 patient used more. Thirteen patients were very satisfied with the overall results of the surgery, 4 were satisfied, and 4 were not satisfied. Two patients were satisfied with their increased function but were not satisfied with their pain reduction. All were satisfied with their cosmetic appearance. Minor complications after the procedure included 3 patients who had preauricular paresthesia and 1 who had an intraoperative dura mater exposure without sequelae. Two patients had postoperative superficial suture infections, and 2 noted hearing changes that were found to be clinically insignificant by audiologic examination. CONCLUSION: The temporalis myofascial flap is an autogenous graft that has the advantages of close proximity to the temporomandibular joint, minimal surgical morbidity, and successful clinical results. It was found to be a valuable option for TMJ reconstruction in joints in which alloplastic, allogeneic, or autogenous materials have previously been placed unsuccessfully.

Preoperative, intraoperative, and postoperative management of patients with obstructive sleep apnea syndrome.

The patient with untreated, obstructive sleep apnea may present difficult or potentially life-threatening challenges to the surgical team. This is true even if the anticipated surgery is remote to the upper airway. Preoperative recognition of the obstructive apnea is essential as the first step in preventing potential complications. When recognized, intraoperative and postoperative initiative can result in a satisfactory outcome.

Correlation of inflammatory cytokines with arthroscopic findings in patients with temporomandibular joint internal derangements.

PURPOSE: The goal of this study was to evaluate the presence of the inflammatory cytokines interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) within the superior temporomandibular joint (TMJ) space in patients with internal derangements and to compare these values with the pathologic findings seen arthroscopically. PATIENTS AND METHODS: Thirty patients with symptomatic TMJ dysfunction and clinical and imaging evidence of internal derangements of the TMJ were evaluated. Before entering the superior joint space with the arthroscope, 2 mL sterile saline was injected and, after 30 seconds of equilibration, was aspirated for analysis. The surgeon then performed diagnostic arthroscopy. The degree of synovitis, degeneration, percent condylar roofing, and any pathologic changes, such as perforations, were recorded. The level of total protein in each sample was ascertained, as well as the levels of IL-1 beta, IL-6, and TNF-alpha. RESULTS: Of 30 samples tested, three were discarded because of failure to gain access into the superior joint space. Of the 27 remaining samples, IL-6 showed the closest correlation with the level of acute synovitis demonstrated arthroscopically. Two of the higher IL-6 levels (167 and 324 pg/microg protein) were seen with patients with a significant disc perforation. In patients with a high degree of vascularity, IL-6 was found to be between 0 to 581 pg/microg protein with an average of 80 pg/microg protein and a median value of 43 pg/mg. These values significantly correlated with the degree of vascularity (P < or = .02). This is in comparison with the 10 remaining patients, who showed significantly fewer vascular changes arthroscopically. In these patients, the range of IL-6 was 0 to 35 pg/microg protein, with an average of 19 pg/microg protein and a median value of 14.5 pg/microg. These values significantly correlated with the smaller degree of vascularity (P < or = .02). In seven patients, the role of nonsteroidal antiinflammatory drug (NSAID) use resulted in decreased levels of IL-6, which has been noted in previous studies. In patients with higher rated redundancy of the synovial tissue, the average IL-6 level was 92 pg/microg protein, whereas the median value was 44 pg/microg protein. In patients with little or no redundant synovial tissue, an average IL-6 level of 22 pg/microg protein was present. The median value in these same joints was 15 pg/microg protein. These IL-6 values significantly correlated with the degree of redundancy (P < or = .03). The degree of degenerative change (chondromalacia, fibrillation), disc displacement (roofing), and the presence or absence of adhesions did not significantly affect the levels of IL-6 within the patients studied. The presence of IL-1 beta and TNF-alpha was not found to correlate with the arthroscopic findings in the superior joint space. CONCLUSIONS: The presence of IL-6 correlated with the degree of acute synovitis. IL-1 beta and TNF-alpha were not found in significant levels within the superior joint space. These findings correlated with those reported by other investigators. The production of IL-6 by synovial cells and its role in TMJ disease warrants further investigation.

Pharmacology of agents used in the management of patients having skin resurfacing.

Many medications are used in the preparation, operative, and postoperative phases of skin resurfacing. This article reviews those medications that impact on laser, chemical peel, and dermabrasion surgery. Facial cosmetic surgeons must fully appreciate the "chemistry" of skin resurfacing.

Changes in facial movement after maxillary osteotomies.

PURPOSE: Determine changes in facial movement while smiling after maxillary Le Fort I osteotomies. MATERIALS AND METHODS: Twenty patients (ages 15 to 38) treatment-planned for maxillary Le Fort I osteotomies were divided into two groups. Group A consisted of 10 patients who underwent superior and/or posterior positioning of the maxilla. Group B consisted of 10 patients who underwent anterior and/ or inferior repositioning of the maxilla. All patients underwent preoperative and postoperative (3 to 8 months) videographic analysis of a maximal closed mouth smile by the Johnson Maximal Static Response Assay, evaluating four landmarks around the mouth and nose (alar base--A, cheilion--C, labrale superioris--Ls, and intermediate between cheilion and labrale superioris--Im). RESULTS: Group A was noted to have a statistically significant decrease in movement of the face at points C and Im. No significant change was seen for points Ls and A. Group B was noted to have a statistically significant increase in movement of the face at point A, C, and Im. Point Ls was also found to increase, however not significantly. CONCLUSION: Surgical repositioning of the maxilla anteriorly and/or inferiorly lengthens the facial musculature resulting in an increase in facial movement while smiling. Likewise surgically repositioning the maxilla superiorly and/or posteriorly reduces the length of the facial musculature, resulting in a decrease in facial movement while smiling.

Intramuscular temporalis fascia: a guide to procurement of temporalis myofascial flaps.

The purpose of this study is to demonstrate an intramuscular fascial layer within the temporalis muscle. This can be used as an inferior plane when developing a temporalis myofascial flap for temporomandibular joint reconstruction. The advantages of using this plane include relatively bloodless zone, adequate thickness of flap for reconstructive purposes, and residual temporalis muscle to prevent the temporal concavity deformity. Cadaveric and clinical examples are presented.

Economic analysis and its application to oral and maxillofacial surgery.

PURPOSE: Recent clinical publications have increasingly emphasized comparison of cost with benefits in such areas such as drug therapies, surgical procedures, and prophylaxis regimes within certain populations. In the past, cost analysis was based principally on the comparative market price of new treatment compared with standard therapy. Benefits were assessed solely in terms of objective clinical and imaging improvement. Now, issues such as quality of life, early return to occupation, and subjective symptoms of pain and discomfort caused by a treatment are also being critically evaluated. Addressing these latter issues, however, is often complicated and expensive. This article reviews some terms and principles of cost analysis, cost effectiveness, and cost-benefit analysis. Examples are given of recent attempts to quantify costs and benefits for individuals, hospitals, health organizations, and society as a whole. Guidelines are suggested concerning how these studies can be applied to oral and maxillofacial surgery.

Relationship of the infraorbital nerve and vessels in the pathogenesis of idiopathic trigeminal neuralgia: a theoretical discussion and cadaveric study.

Many etiologies have been postulated to explain the pathogenesis of Trigeminal Neuralgia (TN). Most theories focus on a demyelinating process resulting in ephaptic transmission and recruitment of small pain fibers or a restrictive relationship of the superior cerebellar arteries and the trigeminal nerve roots at the level of the pons which may lead to demyelination. It is postulated that vasodilation or constriction of these vessels in a confined bony canal can create localized regions of demyelination and restrictive relationships creating painful stimuli. It is the purpose of this study to grossly investigate the relationship of the infraorbital nerve and vessels passing through the infraorbital canal to discuss whether their relationship may play a role in the pathogenesis of idiopathic TN. Patterns of relationship have been elucidated and will be described. This preliminary gross anatomical study should set the framework from which to base further microscopic and clinical studies.

Nuclear dacryoscintigraphy: its role in oral and maxillofacial surgery.

Obstruction of the lacrimal drainage apparatus may result in excessive tearing or epiphora. This may occur as a result of a traumatic injury or accumulation of debris, mucus, or pus. In nuclear dacryoscintigraphy, a radioactive solution is introduced into the conjunctival sac by pipette and allowed to follow the flow of the tear solution through the lacrimal drainage system. This article will review normal lacrimal anatomy and indications for nuclear dacryoscintigraphy in oral and maxillofacial surgery.

Management of condylar fractures in children: review of the literature and case presentations.

The treatment of mandibular condylar fractures has remained a controversial subject. Although many fractures can be treated by closed reduction with subsequent physiotherapy, others are treated by open reduction and rigid internal fixation. The management of these fractures in children and adolescents is more controversial. This article will review the treatment options for condylar fractures in children along with indications and contraindications for open repair.