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Purpose: To further evaluate a novel treatment protocol for the management of aggressive giant cell lesions (GCLs) consisting of enucleation followed by adjuvant subcutaneous interferon alpha therapy., Patients and Methods: Using a retrospective case series study design, a sample of patients with aggressive GCLs was enrolled between April 1995 and June 2006. Lesions were enucleated with preservation of vital structures. Postoperatively, the patients received daily subcutaneous interferon alpha (3 million units/m2 of body surface area). Interferon treatment continued with regular clinical and radiographic follow-up until the surgical defects filled in with bone, as demonstrated by panoramic radiographs and confirmed by computed tomography. Side effects, such as fever, fatigue, weight loss, decreased white blood cell count, decreased platelet count and elevated liver enzymes, were monitored. After completion of interferon therapy, patients followed for 2 years without evidence of recurrence were considered cured of disease., Results: The study sample was comprised of 26 subjects (65% female) with a mean age of 18.5 years. At the time of this writing, 16 of the subjects have completed the protocol and are cured of disease, 6 are in remission, and 4 are in active treatment. Four subjects experienced significant side effects from the interferon, requiring modification of treatment., Conclusions: Enucleation of aggressive GCLs with preservation of vital structures and adjuvant interferon is an excellent strategy for managing aggressive GCLs. Approximately 15% of subjects developed significant side effects limiting interferon administration and necessitating alternative therapies.

Purpose: Osteonecrosis of the jaw (ONJ) has been observed recently in patients with cancer who are receiving intravenous bisphosphonate (BP) therapy. The incidence of BP-associated ONJ has not been well established. The purpose of this study was to determine the incidence of ONJ in a cohort of patients with multiple myeloma (MM), breast cancer (BC), or prostate cancer (PC) who were receiving BP therapy., Patients and Methods: A retrospective chart review was performed. Medical record numbers were identified by ICD-9 codes: 203.0, 203.01, 174.9, and 185.0 for active MM, MM in remission, BC, and PC, respectively. Patients were included if they were evaluated and/or treated between January 1, 2000, and December 31, 2005, and had received zoledronic acid and/or pamidronate. Patients were excluded if they had a history of radiation therapy to the jaws or of tumors or cysts. ONJ was defined as clinical evidence of "exposed necrotic bone" in the mouth., Results: Through evaluation of 1,086 patient medical records, it was determined that 447 subjects met the inclusion criteria: 11 of 292 patients with MM (3.8%; 95% confidence interval [CI], 1.6%, 6.0%) had ONJ, as did 2.5% of 81 patients with BC (0%, 6.9%) and 2.9% of 69 patients with PC (0%, 5.9%)., Conclusion: The incidence of ONJ associated with intravenous BPs was at least 3.8 per 100 patients with MM, 2.5 per 100 patients with BC, and 2.9 per 100 patients with PC during the 5-year study period. The next phase of this study involves assessment of risk factors that differentiate these patients from those treated with BPs who do not develop ONJ.

Purpose: This study evaluated the relationship between timing of lingual nerve repair and functional sensory recovery., Materials and Methods: Using a retrospective cohort study design, the investigators enrolled a sample of subjects who had lingual nerve repair. The predictor variable was time between injury and repair, categorized as early (<90 days after injury) or late (>90 days after injury). The outcome variable was the time to functional sensory recovery (FSR), measured in days. Other variables were categorized as demographic, anatomic, and operative. Uni- and multivariate Cox proportional hazards models were used to evaluate the association between the timing of the repair and time to FSR., Results: The study sample was composed of 64 subjects who had lingual nerve repair between January 1998 and January 2005. The mean time between injury and repair was 153.2 (31-1606) days; 21.9% of subjects had early repair. The mean age was 28.4 +/- 8.0 years, 62.5% of subjects were female; 77% of the injured nerves were repaired by direct suture, and 23% had surgical exploration with decompression/neurolysis. In bivariate analyses, early repair, method of repair, and neuroma were statistically or near-statistically associated with time to FSR (P

Idiopathic condylar resorption almost exclusively affects women. Its exact etiology and pathogenesis remain unclear. It has been associated with rheumatoid arthritis, temporomandibular joint internal derangement, condylar fractures, connective tissue or autoimmune diseases, orthodontic treatment, and orthognathic surgery. In most cases, however, there is no identifiable precipitating event, hence the term "idiopathic condylar resorption." The female predisposition to this condition may be attributed to the influence of estrogen and prolactin on the bone response. Treatment of idiopathic condylar resorption is controversial. Condylectomy and reconstruction with costochondral graft offer definitive management of active idiopathic condylar resorption.

Purpose: The aim of this study was to estimate the proportion of subjects who achieved functional sensory recovery (FSR) 1 year after inferior alveolar or lingual nerve repair and to identify risk factors associated with failure to achieve FSR., Methods: Using a retrospective cohort study design, we developed a sample composed of subjects who underwent lingual or inferior alveolar nerve repair. Eligible subjects had at least 1 postoperative visit. For subjects having bilateral nerve repair, 1 side was selected randomly for analysis. Predictor variables were categorized as demographic, anatomic, and operative. The outcome variable was the time to FSR, measured in days. Kaplan-Meier survival methods were used to estimate the proportion of subjects with FSR at 1 year. Uni- and multivariate Cox proportional hazard models were used to identify risk factors for the failure to reach FSR at 1 year., Results: The study sample was composed of 60 subjects with a mean age of 28.7 +/- 8.3 years; 68.3% were female. The majority (86.7%) of subjects presented with a preoperative chief complaint of altered sensation and had lingual nerve damage (93.3%) that was repaired by direct suturing (75%). The mean interval between injury and repair was 145.9 +/- 200.0 days. At 1 year postoperatively, 75% of the subjects had achieved FSR (95% confidence interval [CI]: 64% to 86%)., Conclusions: The majority of subjects undergoing trigeminal (V(3)) nerve repair achieved functional sensory recovery within 1 year of surgical repair. Patients with evidence of neuroma formation were less likely to achieve FSR at 1 year in a multivariate model.

Purpose: Patients undergoing enucleation and adjuvant interferon therapy for giant cell jaw tumors have been observed to exhibit exuberant bone formation in the resultant defects. We hypothesize that interferon promotes bone formation by enhancing mesenchymal stem cell (MSC) differentiation and by stimulating osteoblasts. This is a preliminary study to determine the effects of interferon on porcine mesenchymal stem cells (pMSCs) in culture., Materials and Methods: Isolated pMSCs were grown under the following conditions: 1) MSCs alone (negative control); 2) MSCs + osteogenic supplements (positive control); and 3) MSCs + interferon (experimental). Cell cultures were evaluated morphologically, by quantitative DNA analysis, and quantitative and qualitative alkaline phosphatase analysis., Results: Cells treated with interferon exhibited a slower but constant proliferation rate, did not clump, and produced more alkaline phosphatase as compared with the negative control., Conclusion: The data indicate that interferon may act to differentiate MSCs into osteoblasts and to stimulate metabolic activity while not increasing the proliferation rate.

Tissue engineering is a rapidly growing interdisciplinary field that focuses on the interactions between cells, growth factors, and scaffolds to produce replacement tissue and organs. Recent developments in tissue engineering technology include refinements in isolation and differentiation of progenitor cells, 3-D printing technology to produce scaffolds, new biomaterials for scaffolds, and growth factor delivery systems. The purpose of this article is to review advances in biomaterials, scaffolds, and implant coatings for craniomaxillofacial (bone) tissue engineering.

Purpose: The purpose of this study was to determine the range of fixed trajectory curvilinear distraction devices required to correct a variety of severe mandibular deformities., Materials and Methods: Preoperative computed tomography (CT) scans from 18 patients with mandibular deformities were imported into a CT-based software program (Osteoplan). Three-dimensional virtual models of the individual skulls were made with landmarks to track movements. An ideal treatment plan was created for each patient. Upper and lower boundaries for the dimensions of curvilinear distractors were established based on manufacturing and geometric constraints. Then, anatomically acceptable distractor attachment points were identified on the models using proximal and distal grids. Treatment plans were simulated for a series of distractors with varying radii of curvature, elongations (arc-length of device), and placements along the grids. The outcomes using these distractors were compared with the ideal treatment plans. Discrepancies were quantified in millimeters by comparing landmarks in the simulated versus ideal movements., Results: Approximately 400,000 simulated 3-dimensional movements, based on the distractor parameters and variations in placement were computationally evaluated for the 18 cases. It was determined that, by varying distractor placement, a family of 5 distractors, with 3, 5, 7, and 10 cm radii of curvature and a straight-line device, could be used to treat all 18 cases to within 1.8 mm of error., Conclusions: The results of this study indicate that a family of 5 curvilinear distractors may suffice to treat a broad range of mandibular deformities.

The field of minimally invasive surgery is defined as the combination of surgical innovation with modern technology. This article describes the history of surgery and newer developments in endoscopic surgery for mandibular orthognathic surgery.

Purpose: Unilateral mandibular distraction osteogenesis (DO) has been shown to cause gross changes in the mandibular condyle and articular disc. The purpose of this study was to correlate histologic findings with these gross changes in a minipig distraction model., Materials and Methods: Semiburied distractors were placed via submandibular incisions in 15 minipigs. Two unoperated animals served as controls. The protocol consisted of 0-day latency and rates of 1, 2, or 4 mm/day for a 12-mm gap. After the minipigs were killed (at 0, 24, or 90 days), ipsilateral and contralateral condyles and discs were harvested, decalcified, prepared for standard paraffin embedding, and evaluated to determine changes in 1) morphology and thickness of the articular cartilage and subchondral bone and 2) morphology of the disc., Results: In control animals, there were no degenerative changes in the articular cartilage and underlying condylar bone; there were no significant differences in the mean articular cartilage thickness. The temporomandibular joint discs were normal. In experimental animals, distracted condyles showed increasing degenerative changes and mean articular cartilage thickness as the DO rate increased. The discs were thinner. These changes were present, but to a lesser degree, in the contralateral condyles. After 90 days, degenerative changes in the condyles and discs were reduced, after remodeling, except in the 4 mm/day DO group., Conclusions: Histologic changes in the condyles and temporomandibular joint discs in response to mandibular DO correlated with previously reported gross changes. These changes were greater at higher distraction rates and remodeling back to normal occurred in mandibular condyles distracted at 1 mm/day.

During the last 25 years, there have been considerable advances in the prevention, diagnosis and management of craniomaxillofacial injuries in children. When compared to adults, the pattern of fractures and frequency of associated injuries are similar but the overall incidence is much lower. Diagnosis is more difficult than in adults and fractures are easily overlooked. Clinical diagnosis is best confirmed by computed tomographic (CT) scans. Treatment is usually performed without delay and can be limited to observation or closed reduction in non-displaced or minimally displaced fractures. Operative management should involve minimal manipulation and may be modified by the stage of skeletal and dental development. Open reduction and rigid internal fixation is indicated for severely displaced fractures. Primary bone grafting is preferred over secondary reconstruction and alloplastic materials should be avoided when possible. Children require long-term follow-up to monitor potential growth abnormalities. This article is a review of the epidemiology, diagnosis and management of facial fractures in children.

During the last 25 years, there have been considerable advances in the prevention, diagnosis and management of craniomaxillofacial injuries in children. When compared to adults, the pattern of fractures and frequency of associated injuries are similar but the overall incidence is much lower. Diagnosis is more difficult than in adults and fractures are easily overlooked. Clinical diagnosis is best confirmed by computed tomographic (CT) scans. Treatment is usually performed without delay and can be limited to observation or closed reduction in non-displaced or minimally displaced fractures. Operative management should involve minimal manipulation and may be modified by the stage of skeletal and dental development. Open reduction and rigid internal fixation is indicated for severely displaced fractures. Primary bone grafting is preferred over secondary reconstruction and alloplastic materials should be avoided when possible. Children require long-term follow-up to monitor potential growth abnormalities. This article is a review of the epidemiology, diagnosis and management of facial fractures in children.

Fibro-osseous lesions are benign mesenchymal skeletal tumors in which mineralized tissue, blood vessels, and giant cells in varying proportions replace normal bone. Included in this group are fibrous dysplasia, cherubism, ossifying fibromas, and osteoblastoma, with fibrous dysplasia being the most common entity. Although fibro-osseous lesions have similar histologic and radiographic features, they may exhibit a wide range of biologic behaviors. Because the histologic appearance does not predict the rate of growth or prognosis, treatment is based on the clinical and biologic behavior of the tumor. The purpose of this article is to describe advances in diagnosis and management of fibro-osseous lesions.

Tooth loss accompanied by alveolar bone resorption presents a significant clinical problem. We have investigated the utility of a tissue-engineering approach to provide corrective therapies for tooth-bone loss. Hybrid tooth-bone tissues were bioengineered as follows. Tooth implants were generated from pig third molar tooth bud cells seeded onto polyglycolide (PGA) and polyglycolide-colactide (PLGA) scaffolds, and grown for 4 weeks in the omenta of adult rat hosts. Bone implants were generated from osteoblasts induced from bone marrow progenitor cells obtained from the same pig, seeded onto PLGA fused wafer scaffolds, and grown for 10 days in a rotational oxygen-permeable bioreactor system. The tooth and bone implants were harvested, sutured together, reimplanted, and grown in the omenta for an additional 8 weeks. Histological and immunohistochemical analyses of the excised hybrid tooth-bone constructs revealed the presence of tooth tissues, including primary and reparative dentin and enamel in the tooth portion of hybrid tooth-bone implants, and osteocalcin and bone sialoprotein-positive bone in the bone portion of hybrid tooth-bone constructs. Collagen type III-positive connective tissue resembling periodontal ligament and tooth root structures were present at the interface of bioengineered tooth and bone tissues. These results demonstrate the utility of a hybrid tooth-bone tissue-engineering approach for the eventual clinical treatment of tooth loss accompanied by alveolar bone resorption.

Purpose: The purpose of this study was to compare objective and subjective assessments of neurosensory function after trigeminal nerve repair., Methods: This was a retrospective cohort study using a sample of patients who underwent surgical repair of trigeminal nerve injuries. The primary study variables were categorized as objective or subjective. The objective variable was the change in neurosensory examination between preoperative and 1-year postoperative visits. Neurosensory status was measured using an ordinal scale ranging from anesthetic (0) to normal (4). Subjective variables included patient satisfaction with the nerve repair and patient assessment of injury-related oral dysfunction. Demographic, anatomic, and operative variables were also collected. Appropriate univariate and bivariate statistics were computed., Results: The sample was composed of 19 patients (14 female, 17 Caucasian) who had trigeminal nerve repair (17 lingual, 2 inferior alveolar). The mean duration between injury and repair was 4.5 +/- 2.3 months; between repair and postoperative assessment was 11.9 +/- 0.9 months. The mean change in neurosensory status was 1.3 +/- 1.0 levels. The majority of patients (63.1%) rated their satisfaction with the outcome of treatment as "good" to "excellent." There was a statistically significant correlation between change in neurosensory status and patient satisfaction (rho = 0.86; P < .01)., Conclusion: There is evidence of a strong correlation between improvement in the neurosensory examination following trigeminal nerve repair and patient satisfaction with the surgical outcome 1-year postoperatively. Patients who experience greater neurosensory improvement also report lower frequencies of related oral dysfunction.

Purpose: The purpose of this study was to evaluate mandibular lengthening by distraction osteogenesis (DO) to achieve decannulation of micrognathic children with "permanent" tracheostomies., Patients and Methods: Using a retrospective chart review, patients were included who had 1 ) airway compromise/tracheostomy, 2 ) micrognathia, 3 ) polysomnography-documented obstructive apnea, and 4 ) mandibular advancement using DO. Excluded were 1 ) adults, 2 ) neonates without tracheostomy, and 3 ) patients with central apnea. Patient age, past medical history, age at tracheostomy, and distraction protocol were documented. Oxygen saturation, posterior airway space (in millimeters), and sella-nasion-B point (SNB) angle were recorded. The distraction protocol consisted of a latency of 48 hours and a rate of 1 mm/day., Results: There were 5 children, aged 2 to 14 years, who received a tracheostomy between ages 2 and 36 months for airway obstruction. All patients underwent bilateral mandibular distraction using semiburied, unidirectional devices. The average latency was 58 hours, the rate was 1 mm/day, the duration of fixation was 40 to 60 days, and the magnitude of advancement was 23 mm. Healing was evaluated by clinical, radiologic, and ultrasound examinations. No complications were experienced. Mean follow-up was 3.2 years. Postdistraction sleep studies demonstrated no obstructive apneic events and a mean oxygen saturation of 98% (preoperative, 76%, P < .005). Cephalometric values improved: posterior airway space 4 to 14 mm; SNB 66 degrees to 72 degrees ( P < .005 for both variables). Four of the 5 patients have been successfully decannulated to date., Conclusions: The results of this preliminary study indicate that mandibular advancement by DO is a potentially viable treatment option for tracheostomy-dependent children with upper airway obstruction secondary to micrognathia.

Purpose: Synovial chondromatosis (SC) is a benign monoarticular condition that is uncommon in the temporomandibular joint (TMJ). The purpose of this article is to present 11 additional cases of SC of the TMJ and discuss newer modes of imaging, diagnostic approaches, treatment options, and follow-up data., Methods: Medical records of 11 patients with SC treated within our department from 1991 to the present were reviewed. Demographic data, etiology, clinical presentation, diagnostic evaluation, treatment, and follow-up information were collected. Previously reported cases (both TMJ and others) from 1988 to present were identified for comparison and the literature reviewed., Results: There were 8 females and 3 males with an average age of 54 years. Pain and preauricular swelling were the most common presenting clinical complaints. Etiologic factors (parafunction, inflammatory joint disease) were found in 7 of 11 cases. Plain radiographs showed joint calcifications in only 2 of 11 cases. Computed tomography identified calcifications in 3 of 6. Magnetic resonance imaging clearly demonstrated the mass and its extension in 10 of 10 cases. Fine needle aspiration was diagnostic in 4 of 9. All patients were treated with an open arthrotomy. Meniscectomy was required in 7 of 11. Average follow-up was 5.2 years with no recurrences reported., Conclusion: The current case series of SC shows a female predilection with age and presenting complaints similar to those previously reported. A traumatic etiology was not identified, although a weak association is reported in the literature. The superiority of magnetic resonance imaging for both diagnosis and evaluation of extension of disease is shown. In a subset of cases, fine needle aspiration is useful for confirming the clinicoradiographic impression. Complete removal of involved tissue is associated with an excellent prognosis.

The purpose of this study was to document the progression and pattern of endosteal bone formation in a porcine mandibular distraction wound. Bone formation was assessed in a 0-day latency model (n=24 pigs) using distraction rates of 1, 2, or 4 mm/day to create a 12-mm gap. Macro-radiographs and sagittal histologic sections, from the center of the mandible, were evaluated by computer morphometrics (% bone fill) and by a semi-quantitative bone formation score. Mean percent area of new bone was 12.4% (0-25.9%), 7.5% (0-21.3%) and 3.8% (0-10.5%) in mandibles distracted at 1, 2 or 4 mm/day respectively. At all time points, percent area of new bone was highest in mandibles distracted at 1 mm/day. Bone was deposited from the margins of the osteotomy toward the center of the wound and occurred first around the inferior alveolar canal and tooth bud regions. New bone formed by intramembranous ossification alone. The results of this experiment document the contribution of endosteal bone formation in this model of distraction osteogenesis.

Purpose: The purpose of this study was to use geometric parameters of movement, calculated from 3-dimensional computed tomography (CT) data, to determine the curvilinear distractor dimensions required to correct mandibular deformities in a series of patients., Materials and Methods: Preoperative CT scans from 15 patients with symmetric (n = 5) and asymmetric (n = 10) deformities were imported into a CT-based software program (Osteoplan; an open-source visualization application developed by Gering et al at the Surgical Planning Laboratory [SPL, Brigham and Womens Hospital, Boston, MA]). The software was used to reconstruct virtual 3-dimensional models from these scans. Two experienced surgeons, working with a computer scientist, then used Osteoplan to create an ideal treatment plan for each patient. In each case, the 3-dimensional curvilinear movement was quantified using 4 "parameters of movement" (POMs). These parameters were then used to prescribe a distraction device capable of executing the planned skeletal correction. Curvilinear distractor dimensions calculated by Osteoplan included the radius of curvature of the prescribed device, and the distractor elongation, pitch, and handedness., Results: Treatment plans including POMs were developed for each patient. The radii of curvature for the prescribed distractors ranged from 2.3 to 14.1 cm, the distractor elongation dimensions ranged from 0.7 to 3.2 cm, and the pitch (horizontal plane) dimensions ranged from 0.005 to 0.8 cm. Handedness was either a left (n = 12) or right (n = 8) turning helix., Conclusion: The results of this study indicate that, using geometric parameters of movement calculated from 3-dimensional CT scans, curvilinear devices could be prescribed for correction of the range of skeletal deformities in this group of patients.

The purpose of this study was to document the progression of bone formation in a porcine mandibular distraction wound, at various distraction rates and fixation times, using three-dimensional computed tomography. Bone formation was assessed in a 0-day latency model (n=24 minipigs) using distraction rates of 1, 2, or 4 mm/day to create a 12 mm distraction gap. Animals were sacrificed at 0, 8, 16, or 24 days fixation. For experimental and control sides, three-dimensional data from computed tomographic scans were used to calculate the percent bone volume in the regions of interest. Standardized plain radiographs were used to evaluate bone formation with a semiquantitative scale: 0, 1, 2, 3. Mean percent bone volume and radiographic bone fill scores (pooled sample) increased with fixation time from 16.8% and 0.17 at 0 days, to 64% and 2.0 at 24 days fixation. Mandibles distracted at 1mm/day had higher CT values and bone fill scores than mandibles distracted at 2 or 4 mm/day. At 24 days fixation, the maximum percent bone volume (64%--1 mm/day; 24 days fixation) remained below control values (81.3%). The results of this study indicate that despite high bone fill scores on plain radiographs, the highest percent CT bone volume achieved in this model was 64%.

Purpose: The benefits of minimally invasive surgery have been well documented. The purpose of this report was to present early results in a series of patients who had endoscopic mandibular orthognathic surgery. Patients and methods This is a retrospective evaluation of 14 patients who underwent endoscopic vertical ramus osteotomy and rigid fixation for the treatment of mandibular prognathism (n = 9), malocclusion secondary to trauma (n = 3), or other pathology (n = 2). A 1.5-cm incision was made directly below the mandibular angle. The dissection was continued bluntly to the masseter muscle, which was incised using a needlepoint electrocautery. Then, with endoscopic elevators, an optical cavity was created for insertion of a Hopkins endoscope and visualization of the ramus/condyle unit. Anatomic landmarks were identified and the operation carried out with specially designed endoscopic equipment. Preoperative (T0), postoperative (T1), and follow-up (T2) clinical examinations; lateral cephalograms; and panoramic radiographs were used to evaluate the outcomes., Results: The procedures performed included: vertical ramus osteotomy (n = 13 patients, 23 sides) and condylectomy plus vertical ramus osteotomy (n = 1 patient, 1 side). Mean operating time was 37 minutes per side. One patient had temporary marginal mandibular nerve weakness. The occlusal result was as planned in all cases. Panoramic radiographs documented postoperative ramus/condyle unit position and lateral cephalograms documented mandibular position., Conclusions: The results of this case series indicate that endoscopic vertical ramus osteotomy with rigid fixation is feasible for correction of a variety of mandibular deformities.

Purpose: The purpose of this study was to document perioperative neurosensory changes in the inferior alveolar nerve (IAN) after mandibular fracture treatment and to identify risk factors associated with these changes., Materials and Methods: This was a prospective cohort study composed of patients treated for mandibular fractures. The primary study variable was the change between the postinjury/pretreatment IAN neurosensory examination score and the score after fracture reduction. Risk factors were categorized as demographic, anatomic, and treatment. Appropriate descriptive, bivariate, and multivariate statistics were computed., Results: The cohort was composed of 61 patients with 97 fractured sides. Forty-seven fractures (49%) were located between the lingula and mental foramen, and 50 fractures (51%) were located distal to the mental foramen. Thirty-nine fractures (41%) were displaced by 5 mm or more. Abnormal preoperative IAN neurosensory examinations were documented in 81% of the fractured sides. Fifty-three fractures (54%) were treated by closed reduction and 44 (46%) by open reduction and internal fixation. In 82 fractures (85%), the IAN neurosensory score was unchanged or improved after treatment. In a multivariate model, preoperative neurosensory score, displacement, and treatment were associated with a statistically significant risk (P < or =.05) for postoperative deterioration of IAN sensation., Conclusion: Open reduction and internal fixation, fracture displacement of 5 mm or more, and a normal preoperative IAN neurosensory examination were associated with an increased risk for deterioration of the IAN neurosensory score after treatment of mandibular fractures. Additional studies are indicated to determine long-term IAN neurosensory function after mandibular fracture treatment and the factors that affect prognosis.

Purpose: Maxillofacial reconstructive procedures often require bone graft harvesting, which results in donor site morbidity; the use of tissue-engineered bone would eliminate this problem. In this study, a novel scaffold design and new fabrication protocol were used to produce autologous tissue-engineered constructs (scaffolds seeded with cells) to reconstruct segmental mandibular defects in a minipig model., Materials and Methods: Porcine mesenchymal stem cells were isolated from the ilium. They were expanded in culture and seeded onto poly-dl-lactic-coglycolic acid scaffolds. The constructs were placed in a bioreactor and incubated for 10 days in medium and osteogenic supplements. Four full-thickness bony defects (2 x 2 cm) were created in the same pig's mandible. The constructs (n = 2) were placed into 2 of the defects as autologous grafts. One unseeded scaffold and 1 empty defect served as controls. At 6 weeks postimplantation, the pig was sacrificed, the mandible was harvested, and the grafted sites were evaluated by clinical, radiographic, and histologic methods., Results: The construct-implanted defects appeared to be filled with hard tissue resembling bone, whereas controls were filled with fibrous tissue. Radiographically, the tissue-engineered constructs were uniformly radiodense with bone distributed throughout. The interface between native bone and constructs was indistinct. Complete bone ingrowth was not observed in control defects. Osteoblasts, osteocytes, bone trabeculae, and blood vessels were identified throughout the defects implanted with constructs., Conclusion: This "proof-of-principle" study indicates that porcine mandibular defects can be successfully reconstructed by in vitro cultured autologous porcine mesenchymal stem cells on a biodegradable polymer scaffold with penetration of bone and blood vessels.

Purpose: The purpose of this study was to evaluate early outcomes in patients who underwent endoscopic condylectomy and costochondral graft reconstruction (CCG) of the ramus/condyle unit (RCU)., Patients and Methods: A retrospective evaluation of 10 consecutive patients who underwent endoscopic condylectomy and CCG (n = 17 sides) for the treatment of idiopathic condylar resorption (n = 7), degenerative joint disease (n = 1), and malunion of a fractured condyle (n = 2) was completed. Patients were included who had 1) adequate documentation after endoscopic condylectomy and CCG reconstruction and 2) a minimum of 6-months follow-up. Patients with inadequate documentation or follow-up were excluded. The surgical technique included a 1.5-cm incision inferior to the mandibular angle. Blunt dissection was carried to the masseter muscle, which was incised using needle point electrocautery. An optical cavity was created for insertion of a Hopkins (Karl Storz, Culver City, CA) endoscope. The resection and reconstruction were carried out with endoscopic instrumentation. Preoperative (T0), postoperative (T1), and follow-up (T2) clinical examinations, lateral cephalograms, and panoramic radiographs were used to evaluate the outcomes., Results: In all 10 cases, condylectomy and CCG reconstruction (n = 17 sides) were successfully performed using the endoscopic approach. The mean follow-up period was 17 months (range, 8 to 38 months). All submandibular scars were aesthetically satisfactory, and there were no facial, inferior alveolar, or lingual nerve injuries. No other intraoperative or postoperative complications occurred. Postoperative RCU length, mandibular position, and correction of the occlusion were documented using lateral cephalometric and panoramic radiographs., Conclusion: The results of this study indicate that endoscopic condylectomy and CCG reconstruction produce satisfactory clinical outcomes without significant morbidity. Long-term follow-up studies are in progress.

Purpose: The purpose of this study was to evaluate a staged protocol for resection of jaw tumors and reconstruction including implants in pediatric patients., Patients and Methods: Nine children were evaluated retrospectively. Data included age at resection, tumor type, use of adjuvant therapy, type of bone graft, and number of implants. Occurrence of postoperative infection, tumor margins, recurrence, plate fractures, number of bone grafts, implants restored, and failures were recorded., Results: Ages ranged from 3.5 to 16 years with 2 maxillary and 7 mandibular tumors. Diagnoses included giant cell lesion (n = 3), osteosarcoma (n = 2), myofibroma (n = 1), ossifying fibroma (n = 1), desmoplastic fibroma (n = 1), and ameloblastoma (n = 1). No patients experienced postoperative infection, wound dehiscence, or jaw instability after en bloc resection. One patient had recurrence of a giant cell lesion. To date (mean, 56 months; range, 24 to 93 months), there have been no additional recurrences. There was 1 plate fracture. Eight patients underwent iliac bone grafts (stage 2), and in 1 patient, the mandible regenerated. There were no graft infections or wound dehiscences. Three patients required additional bone grafting for implant placement. Twenty-three implants were placed in 7 patients without complications, and 21 implants have gone to second stage. One implant failed to osseointegrate. Six patients have had prostheses placed and loaded for a mean of 26 months (range, 5 to 64 months). One patient is scheduled for prosthetic restoration and 2 for implant placement., Conclusion: Pediatric maxillofacial tumors can be successfully treated by resection, rigid fixation, and delayed reconstruction with minimal morbidity and a high success rate.

Distraction osteogenesis is a technique for skeletal lengthening that exploits the body's innate capacity for bone formation in response to tension forces on the repair callus. The authors developed a distraction osteogenesis model with a semiburied device in the Yucatan minipig mandible because of similarities between human and porcine mandibular anatomy, temporomandibular function, chewing patterns, and bone turnover rates. The purpose of this study was to measure histomorphometric bone fill after different latency periods, rates of distraction, and duration of neutral fixation in the minipig mandible. In addition, the relationship between histomorphometric bone fill and clinical stability was investigated. Mandibular osteotomies in 20 female Yucatan minipigs weighing 25 to 30 kg were distracted with modified semiburied distraction devices. Variables included 0-day or 4-day latency; 1-mm, 2-mm, or 4-mm daily distraction rates; gap size of 7 or 12 mm; and evaluation after neutral fixation for various lengths of time. Specimens were fixed in 2% paraformaldehyde, pH 7.4, before being embedded in methylmethacrylate. Sections were prepared from the region just below the inferior alveolar canal. The area of new bone formation within the gap was measured and expressed as a percentage of the total area of the distraction gap. Bone fill ranged from 0 to 100 percent. A pilot study with 7-mm advancements showed similar bone fill with 0-day or 4-day latency, but with poor reproducibility. Mandibles that were distracted to 12 mm at 1 mm per day exhibited nearly complete bone fill, either with 0-day latency (average, 93 percent) or 4-day latency (average, 100 percent). Mandibles that had been distracted for 3 days at 4 mm per day showed moderate osteogenesis and clinical stability with increasing time of neutral fixation. Bone fill was significantly correlated with clinical stability (Spearman r = 0.801, p = 0.001). Histological examination showed exuberant periosteal osteogenesis in distracted mandibles, even in those that showed poor bone fill and clinical stability. Thus, the periosteum appears to be a major source of new bone formation. These results show that osteogenesis was nearly complete with 1 mm per day and 0-day or 4-day latency. These results are consistent with the authors' previously reported clinical and radiographic observations that a latency period is not necessary for successful healing of the mandibular distraction osteogenesis wound.

Purpose: The first resident enrolled in the Massachusetts General Hospital/Harvard MD Oral and Maxillofacial Surgery (MD/OMFS) program graduated from Harvard Medical School (HMS) in 1972. The purpose of this report is to provide a summary of the first 30 years of the program and to outline plans for its future., Materials and Methods: This was a retrospective cohort study and the sample was composed of the residents enrolled in the MD/OMFS program between 1971 and 2000. Study variables included the dental school from which the resident graduated, successful completion of the MD/OMFS program, performance on parts I and II of the United States Medical Licensing Examination/National Board of Medical Examinations (USMLE/NBME), HMS grades, and career trajectories (full- or part-time academic or private practice). Appropriate descriptive and bivariate statistics were computed for all study variables., Results: During the study interval, 56 residents entered the MD/OMFS program and graduated from HMS. All members of the cohort, regardless of the dental school from which they graduated, performed well as evidenced by USMLE/NBME scores and medical school grades. Ninety-four percent of eligible graduates have completed the American Board of Oral and Maxillofacial Surgery examination. The pass rate was 100%. Thirty-four graduates are involved in full- or part-time academic practice. Four trainees completed medical school but did not complete the OMFS program., Conclusion: The overwhelming majority of trainees completed the program, became board certified, and currently practice OMFS or a related specialty. A disproportionate number entered academic careers.

Purpose: Common methods of assessment of the clinical distraction osteogenesis (DO) wound consist of serial physical examinations, plain radiographs, and computed tomography (CT). Ultrasound (US) is an inexpensive and efficient method of imaging that provides detailed assessment of bone formation across a defect. It has proved to be useful for the evaluation of long bone DO healing. The purpose of this study was to determine the efficacy of US for evaluation of bone formation in the mandibular distraction wound., Patients and Methods: Ten patients underwent mandibular expansion (18 sides) with semiburied, unidirectional distraction devices. The wounds were assessed with plain radiographs and US immediately before device removal. Estimates of bone formation, using a semiquantitative bone fill score, were made for plain radiographs and US. US beam penetration depth, in millimeters, was also measured. During removal of the distraction device, bone formation and mandibular stability were assessed by the surgeon and graded on a semiquantitative scale., Results: US bone fill scores correlated with intraoperative assessment of bone formation and stability (r = 0.758, P =.0018) at all 18 mandibular sites. Plain radiographic scores also correlated with bone formation (r = 0.592). However, in 14 of 18 sides, plain radiographs underestimated bone formation compared with US and operative findings., Conclusion: The results of this study indicate that US is an accurate noninvasive technique that may prove to be useful in assessing the mandibular DO regenerate in patients.

The purpose of this study was to develop a mechanical testing system to estimate stiffness of an experimental porcine mandibular distraction osteogenesis (DO) wound. The system was designed to function without changing the morphology of the healing mandible. A customized jig was designed to allow cantilever-bending tests of the Yucatan mini-pig hemi-mandible. Experimental and control hemi-mandibles were placed in the jig and the proximal segment was secured. A material testing unit applied progressively increasing downward force on the pre-molar occlusal surface. The maximum force applied was 0.030 kN. The stiffness value for each hemi-mandible was represented by the slope of the plot of force (kN) vs displacement (mm). Radiographs were taken before and after mechanical testing to demonstrate any gross morphologic changes or identifiable fractures across the distraction wound. A total of 24 mini-pigs underwent DO of the right mandible with 0-day latency and distraction rates of 1, 2, and 4 mm per day resulting in a 12 mm gap. At the completion of 0, 8, 16, and 24 days of neutral fixation, two animals for each of three different distraction rates were sacrificed for mechanical testing. Stiffness of control hemi-mandibles ranged between 0.018 and 0.317 kN/mm (median 0.063; mean 0.099 +/- 0.080). Stiffness of experimental hemi-mandibles ranged between 0 and 0.025 kN/mm (median 0.004; mean 0.005). The subset that was tested at the end of neutral fixation had stiffness between 0.005 and 0.025 (median 0.011; mean 0.012 +/- 0.011). No morphologic changes were evident on the X-rays after testing. The results indicate that the cantilever-bending model is useful for testing stiffness of an experimental mandibular DO wound without destroying its morphology.

The aim of this study was to determine the stiffness of a porcine mandibular distraction wound at the end of neutral fixation.Twenty-four Yucatan minipigs underwent unilateral mandibular distraction: zero-day latency, rates of 1, 2, and 4 mm per day, distraction gap of 12 mm. Radiographic and ultrasound bone fill scores at 0, 8, 16 and 24 days of neutral fixation were used to evaluate interval healing. At sacrifice, biomechanical stiffness was determined using an Instron machine to produce a downward force of 2 mm/min at the premolar occlusal surface. Force (kilo-Newton, kN) and displacement (mm) were recorded at a rate of 10,000 points/second. Stiffness across the distraction wound, plain radiographic and ultrasound bone fill scores all increased with duration of neutral fixation and were highest for the 1 mm per day group at all time points. At the end of fixation, even in the most clinically stable group, stiffness across the distraction wound was only 25.5% of control.Despite clinical stability and high bone fill scores by X-ray and ultrasound, the distraction wound did not achieve normal stiffness at the end of neutral fixation in this model. This may have implications for the management of patients who undergo large movements by distraction.

Purpose: Cytokeratin-10 expression by cystic epithelium has been shown in the suprabasilar layers of odontogenic keratocyts (OKCs) but not in dentigerous cysts. Cyst decompression and irrigation result in the loss of keratinization. In this study, we used cytokeratin-10 antibody staining to evaluate changes in OKC epithelium to determine if decompression/irrigation treatment results in an epithelial modulation that may be associated with lower long-term recurrence., Methods: Fourteen OKCs were exteriorized by removal of mucosa and bone. An irrigation port was placed into the cyst for twice-daily irrigations. At 3-month intervals, panoramic radiographs were obtained and cyst-lining cells were sampled and stained for cytokeratin-10. Residual cystectomy was performed when necessary based on clinical and radiographic criteria, and the lining was evaluated by histologic and immunohistochemical examination., Results: There were 6 males and 8 females with a mean age of 32 years. Ten cysts were mandibular, and 4 were maxillary. Average duration of irrigation was 8.4 months (range, 6 to 12 months), and the mean shrinkage of the radiolucency was 65% (range, 5% to 91%). All cytologic samples obtained at 3 and 6 months contained cytokeratin-10-positive epithelial cells. At the time of cystectomy, 9 of 14 cases were cytokeratin-10 negative and no longer showed histologic features of OKCs. Specimens from the remaining 5 patients were histologically consistent with OKC and were cytokeratin-10 positive. Mean treatment time of the cytokeratin-10-positive group was 7 months, and that of the cytokeratin-10-negative group was 9 months., Conclusion: Epithelial dedifferentiation and loss of cytokeratin-10 production were observed in 64% of patients treated by cyst decompression/irrigation after a 9-month average treatment time. Longitudinal follow-up of these patients will determine whether this change is associated with lower rates of recurrence than alternative OKC therapy., (Copyright 2003 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 61:678-683, 2003)

Objective: The purpose of this study was to measure patient satisfaction and to evaluate the factors influencing patients' perceptions of the outcome of inferior alveolar nerve or lingual nerve repair., Study Design: We used a retrospective cohort study design and a sample of patients who underwent repair of inferior alveolar nerve or lingual nerve injuries. The major outcome variable was the patient's overall satisfaction with treatment. The patient's satisfaction was rated as either good to excellent (group A) or fair to poor (group B)., Results: The study sample was composed of 46 patients with a mean age of 28 +/- 12 years; 76% were female. Fifty-five percent of the sample reported their overall satisfaction to be good to excellent. No individual predictor factors were statistically associated with patient satisfaction. Among the outcome variables, the measures of taste, pronunciation, self-consciousness, and function were statistically significantly different (P <.05) between the 2 groups., Conclusions: After nerve repair, more than half of the patients rated their overall satisfaction with the operative results to be good to excellent.

Purpose: The purpose of this study was to estimate the association between specific panoramic radiographic signs and inferior alveolar nerve (IAN) injury during mandibular third molar removal., Patients and Methods: A case-control study design was used; the sample consisted of patients who underwent removal of impacted mandibular third molars. Cases were defined as patients with confirmed IAN injury after third molar extraction, whereas controls were defined as patients without nerve injury. Five surgeons, who were blinded to injury status, independently assessed the preoperative panoramic radiographs for the presence of high-risk radiographic signs. Bivariate analyses were completed to assess the relationship between radiographic findings and IAN injury. The sensitivity, specificity, and positive and negative predictive values were computed for each radiographic sign., Results: The sample was composed of 8 cases and 17 controls. Positive radiographic signs were statistically associated with an IAN injury (P <.0001). The presence of radiographic sign(s) had positive predictive values that ranged from 1.4% to 2.7%, representing a 40% or greater increase over the baseline likelihood of injury (1%) for the individual patient. Absence of these radiographic findings had a strong negative (>99%) predictive value., Conclusions: This study confirms previous analyses showing that panoramic findings of diversion of the inferior alveolar canal, darkening of the third molar root, and interruption of the cortical white line are statistically associated with IAN injury. Based on the estimated predictive values, the absence of positive radiographic findings was associated with a minimal risk of nerve injury, whereas, the presence of one or more of these findings was associated with an increased risk for nerve injury., (Copyright 2003 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 61:417-421, 2003)

Purpose: Mandibular reconstructive procedures often produce significant donor site morbidity. Recently, the use of minimally invasive techniques has been reported for mandibular reconstruction with decreased morbidity at the primary operative site. To date, these techniques have not addressed the graft donor site. We hypothesize that tissue-engineering techniques may be used to fabricate bone and thereby eliminate donor site morbidity., Methods: Porcine mesenchymal stem cells (pMSCs) were isolated from the bone marrow of 3 Yucatan minipigs and grown in standard culture flasks. When they became near-confluent, cells were detached and replated with the addition of osteogenic supplements. A model of a porcine mandibular condyle was made and used to fabricate porous polymer scaffolds from biodegradable poly DL-lactic-co-glycolic acid (PLGA). Differentiated osteoblasts were transferred to the PLGA scaffold and cultured for 6 weeks in a rotational oxygen-permeable bioreactor system. The cultured constructs, consisting of scaffold and cells, were evaluated by gross, radiologic, and histologic examinations., Results: The engineered constructs were white and hard and had a shape that closely resembled that of the model condyle. Plain radiographs demonstrated that the radiodensity of the construct was between that of the normal condyle and that of control scaffolds. Histologically, bone was observed on the entire surface of the PLGA scaffolds with an average thickness of 0.03 mm. Bone was not observed in the control scaffolds., Conclusion: In this pilot study, autologous tissue-engineered bone constructs were successfully made by combining biodegradable polymers and pMSCs., (Copyright 2003 American Association of Oral and Maxillofacial Surgeons)

Purpose: Distraction osteogenesis (DO) is a commonly used technique for mandibular lengthening, but changes in the temporomandibular joint have not been well documented. The purpose of this study was to evaluate the effect of DO, at varying rates, on the mandibular condyle and articular disc., Materials and Methods: Semiburied distractors were placed via submandibular incisions in 15 minipigs. Two unoperated animals served as controls. The protocol consisted of 0 day latency and rates of 1, 2, or 4 mm/d for a 12-mm gap. After the animals were killed (0, 24, or 90 days), ipsilateral and contralateral condyles and discs were harvested and evaluated to determine changes in 1) condylar form and size, 2) condylar surface, and 3) the articular disc., Results: Articular surfaces of the condyles in control animals were smooth, with no irregularities or erosions. In animals undergoing distraction, ipsilateral condyles showed increasing changes in morphology and AP dimension, and surface contour irregularities as the DO rate increased. These changes were present, but to a lesser degree, in the contralateral condyles. Articular discs of both ipsilateral and contralateral sides showed variable thinning at the medial aspect at end DO. After 90 days, changes in the condyles and discs were reduced by remodeling except in the 4 mm/d DO groups., Conclusions: Results of this preliminary study indicate that gross changes occur in condyles and discs after unilateral mandibular DO. These changes are more severe at faster distraction rates (4 mm/d) and tend to resolve during neutral fixation when a rate of 1 mm/d is used., (Copyright 2002 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 60:1327-1333, 2002)

Purpose: Giant cell tumors are classified and treated based on their biologic behavior. We hypothesize that they are proliferative vascular lesions and would be expected to respond to antiangiogenic therapy. The purpose of this report is to present a treatment protocol consisting of enucleation, with preservation of vital structures, followed by subcutaneous interferon alpha., Materials and Methods: Patients with a biopsy-confirmed giant cell lesion satisfying criteria for "aggressive giant cell tumor" were included. Instead of wide en bloc resection, lesions were enucleated and the patients started on interferon alpha-2 or beta (3,000,000 units/m(2)) 48 to 72 hours postoperatively. The subjects were followed by clinical examination and radiography, immediately after surgery and every 3 months until the bone cavity completely healed. Thereafter, follow-up was every 6 months., Results: Eight patients (7 females), with a mean age of 18.7 +/- 11.1 years, have been enrolled. Six tumors were in the posterior mandible, and 2 were in the anterior maxilla. The mean size was 29.0 mm (range, 15 to 70 mm). All patients underwent enucleation. There were no postoperative complications, and all patients tolerated interferon. There was no evidence of tumor growth during treatment. Seven of 8 patients have completed interferon therapy, and there have been no recurrences during 1 to 6 years of follow-up. The other patient continues on treatment with no evidence of disease., Conclusion: Antiangiogenic therapy, in combination with curettage, is a promising strategy for treatment of aggressive giant cell tumors. Combined treatment results in a high rate of tumor control with decreased operative morbidity compared with conventional treatment., (Copyright 2002 American Association of Oral and Maxillofacial Surgeons)

Purpose: A standardized, noninvasive technique to assess healing of the mandibular distraction wound is not available. Current methods include clinical examination, plain radiography, and computed tomography. These imaging techniques are expensive and obligate the patient to serial radiation exposure. In addition, anatomic overlap and metal artifacts may obscure the distraction gap. In contrast, ultrasound has been shown to be a noninvasive, efficient, and inexpensive way to evaluate bone healing. The purpose of this study was to test the feasibility of ultrasound to evaluate an experimental mandibular distraction osteogenesis wound., Materials and Methods: Distraction devices were placed via a submandibular incision into 24 minipigs. The protocol consisted of 0-day latency and distraction rates of 1, 2, or 4 mm/d for a 12-mm gap. The wounds were assessed in vivo after 0, 8, 16, and 24 days of neutral fixation. Ex vivo radiographs were used to estimate bone fill using a semiquantitative score. A semiquantitative ultrasound score was assigned, and the beam penetration depth was measured in millimeters., Results: In all groups, clinical stability of the distraction wound increased with the duration of fixation. Plain radiographs, taken during neutral fixation, showed that the desired distraction gap was achieved and maintained. The ultrasound score increased with fixation time, whereas beam penetration depth decreased as expected. Ex vivo radiographs showed increasing bone fill score with time and paralleled the ultrasound score., Conclusions: The results of this feasibility study indicate that ultrasound is potentially useful for the assessment of bone formation in distraction osteogenesis wounds., (Copyright 2002 American Association of Oral and Maxillofacial Surgeons)

Purpose: The incidence of deformational posterior plagiocephaly has increased dramatically since 1992. We tested the hypothesis that mandibular asymmetry, associated with this condition, is secondary to anterior displacement of the ipsilateral temporomandibular joint. The response to molding helmet therapy was also evaluated., Patients and Methods: A caliper was used to measure mandibular dimensions in 27 infants (16 boys and 11 girls) with deformational posterior plagiocephaly; the mean age was 6.2 months (range, 3 to 12 months). Anthropometric measures included ramal height (condylion-gonion), body length (gonion-gnathion), and condylion-gnathion. Gonial angle was calculated from the law of cosines: C(2) = A(2) + B(2) - 2AB cos c. The position of the temporomandibular joint was accepted as corresponding to auricular position and measured from tragion to subnasal. Cranial asymmetry was measured, in the horizontal plane, from orbitale superius to the contralateral parieto-occipital point at the level of inion. Ten of 27 patients were remeasured 5 months after beginning helmet therapy to evaluate change in mandibular dimensions., Results: Two thirds of infants (67%) had right-sided and one third (33%) had left-sided deformational posterior plagiocephaly. The mean auricular anterior displacement was 79.7 mm on the affected side and 83.4 mm on the unaffected side. The mean difference of 3.8 mm between the sides was statistically significant (P <.001). Transverse cranial dimension averaged 136.0 mm on the affected side and 146.8 mm on the unaffected side; this was also significant (P <.001). There was a significant positive correlation between auricular displacement and cranial asymmetry [R(23) =.59, P <.01). Auricular (temporomandibular joint) displacement also resulted in an apparent mandibular asymmetry with rotation of the jaw to the affected side. Mean mandibular measurements on the affected and unaffected sides were ramus height of 35.2 and 36.4 mm, body length of 59.0 and 60.3 mm, and gonial angle of 127.1 degrees and 126.8 degrees, respectively. Comparison of the affected with the unaffected sides, using a paired-samples t test, was not statistically significant. Improvement in cranial asymmetry occurred with helmet therapy, but there was no correction of auricular and temporomandibular joint position., Conclusions: This study supports the clinical observation that the mandibular asymmetry in deformational posterior plagiocephaly is secondary to rotation of the cranial base and anterior displacement of the temporomandibular joint (quantified by anterior auricular position) and not the result of primary mandibular deformity., (Copyright 2002 American Association of Oral and Maxillofacial Surgeons.)

Current surgical treatment planning systems predict three-dimensional (3D) corrections from two-dimensional (2D) data and are inadequate for complex movements. In this paper, we present a 3D planning system based on computed tomographic (CT) data. A three-dimensional CT scan of the craniofacial skeleton forms the database. Software developed in the Harvard Surgical Planning Laboratory was modified for the craniofacial skeleton. Reproducible skeletal landmarks are identified for superimposition. A 'cutting tool' is used to segment the mandible and segments are moved to their predicted positions. A 'collision tool', alerts the operator of skeletal interferences. An analysis of selected scans is used to demonstrate the system. Three-dimensional visualization of the facial skeleton, selection of landmarks, measurement of angles and distances, simulation of osteotomies, repositioning of bones, detection of collisions and super-imposition of scans were accomplished. In an illustrative case of Hemifacial Microsomia, predicted and actual 3D corrective movements of the entire mandible were documented. Analysis of scans indicated that 3D planning can prevent insufficient jaw lengthening or other surgical inaccuracies which occur with standard 2D methods. Software demonstrated here will allow the surgeon to accurately plan treatment and evaluate craniomaxillofacial surgery outcomes. Future applications may include surgical navigation.

Purpose: Entubulization is a well known method of nerve repair for defects too large to be reconstructed by direct suturing without tension. Vein grafts and alloplastic tubes have been used for entubulization in peripheral and cranial nerves, but the mechanism by which they promote healing is poorly understood. The overall hypothesis of this laboratory is that nerve growth factor (NGF) plays an important role in nerve regeneration after entubulization with a vein graft. The purpose of this pilot study was to localize NGF protein expression in the rat femoral vein., Materials and Methods: Sciatic nerves and femoral veins were harvested from adult male Sprague-Dawley rats. Femoral arteries were also collected and used for comparison and validation of the analysis. All specimens were fixed in paraformaldehyde and embedded in paraffin. Specimens were either stained with hematoxylin and eosin or used for immunohistochemical reaction with anti-NGF antibody., Results: Sciatic nerve was used as a positive control to identify the monofascicular architecture with hematoxylin and eosin and to document the positive immunohistochemical reaction. NGF immunoreactivity was present in the tunica intima and tunica adventitia of femoral vein and artery but not in the tunica media., Conclusion: The results of this pilot study indicate that NGF is detectable in both the intimal and adventitial layers of the rat femoral vein and artery but not in the smooth muscle wall. These findings suggest that vein grafts could potentially promote nerve regeneration by supplying NGF to the injured nerve., (Copyright 2002 American Association of Oral and Maxillofacial Surgeons)

The mechanisms that regulate bone formation during distraction osteogenesis (DO) are not completely understood. Our hypothesis is that local cytokines that stimulate osteoblast activity are potential regulators of this process. The purpose of this study was to determine gene expression of insulin-like growth factor I (IGF-I), transforming growth factor-beta (TGF-beta), and bone morphogenetic protein 4 (BMP-4) in distracted wounds. A semiburied, rigid distraction device was placed across an osteotomy at the right mandibular angle in 9 Yucatan minipigs. Distraction was begun immediately at a rate of 1 mm/day. The animals were sacrificed after 4 and 7 days of distraction, and after 7 days of distraction plus 4 days of neutral fixation. Excised wound tissues were processed for histologic and gene expression analyses. Competitive reverse-transcription polymerase chain reaction (RT-PCR) assays were developed and validated for porcine genes. Histologic analysis showed membranous ossification within the DO wound. Gene expression of IGF-I, TGF-beta and BMP-4 was detected during distraction and neutral fixation. These results show that gene expression analyses can be performed in a large animal model of mandibular DO. As the pig mandible closely resembles that of the human in morphology and physiology, this is an important step toward characterization of the early molecular events in the DO wound.

During this 45-minute presentation, I have tried to describe my vision of the exciting future that awaits us. I have tried to impart my enthusiasm for the opportunities provided to us as surgeons by the advances in molecular biology and genetics, imaging, surgical technology and bioinformatics. Most of all, I hope I have transmitted my optimism for the future to our younger members. I think the following statement or observation by the great educator Margaret Mead accurately summarizes our current situation regarding the application of all this new knowledge that will become available to us as surgeons: 'We are now at the point where we must educate people (surgeons) in what nobody knew yesterday, and prepare in our schools (training programs) for what no one knows yet but what some people must know tomorrow.'

Purpose: The purpose of this report is to describe use of an endoscopic technique for exposure of the mandibular ramus/condyle unit (RCU) to facilitate reconstructive jaw procedures., Patients and Methods: This is a retrospective evaluation of 10 patients with diagnoses of idiopathic condylar resorption (n = 2), subcondylar fracture (n = 5), mandibular prognathism (n = 1), condylar hyperplasia (n = 1), and mandibular asymmetry (n = 1), who underwent endoscopic exposure of the RCU., Results: All 10 patients had successful reconstruction of the RCU using the endoscopic approach. The procedures performed included the following: condylectomy (n = 5 sides), costochondral graft reconstruction (n = 4 sides), reduction of subcondylar fracture (n = 5 sides), and mandibular ramus osteotomy (n = 4 sides). Mean operating time was 84 minutes. No patients had marginal mandibular nerve weakness or other complications., Conclusion: This case series demonstrates the feasibility of endoscopic access to the RCU. The procedures can be performed with no increase in operative time and with minimal morbidity., (Copyright 2001 American Association of Oral and Maxillofacial Surgeons)

Purpose: Long-term success of distraction osteogenesis depends on the ability of the surrounding soft tissues to tolerate distraction forces and to adapt to the resulting increase in skeletal length and volume. The hypothesis tested in this study was that mandibular elongation by distraction induces myocyte proliferation., Materials and Methods: Unilateral mandibular angle osteotomies were performed in 16 Yucatan minipigs. The hemimandibles were lengthened using semiburied distraction devices (Synthes Maxillofacial, Paoli, PA) with 0-day latency, 1, 2, or 4 mm/d distraction rates, and a neutral fixation period of twice the gap size in days. In 2 additional animals, the dissection and osteotomies were performed, and distraction devices were placed without activation (sham control). At the end of neutral fixation, tissues were taken from masseter muscle overlying the osteotomy and the equivalent region on the unoperated side (contralateral control). Proliferation of myocytes was estimated using immunohistochemical localization with antibodies against proliferating cell nuclear antigen (PCNA)., Results: Muscle overlying the distracted mandible showed 6-fold more PCNA-positive myocytes (16.8% +/- 11.3%) than the contralateral control side (2.8% +/- 1.1%, P < .0001). In the 2 sham-control animals, there was a low index of PCNA-positive myocytes on both the osteotomy (2%, 5%) and the contralateral sides (1%, 2%)., Conclusions: The results of this study suggest that distraction of the porcine mandible by the protocol described induces myocyte proliferation in the masseter muscle. A proliferative response may contribute to improved long-term stability of mandibular expansion by distraction osteogenesis.

Purpose: The aim of this study was to compare the cost-effectiveness of mandibular fracture treatment by closed reduction with maxillomandibular fixation (CRF) with open reduction and rigid internal fixation (ORIF)., Patients and Methods: This was a retrospective study of 85 patients admitted to the Oral and Maxillofacial Surgery Service at San Francisco General Hospital and treated for mandibular fractures from January 1 to December 31, 1993. The patients were divided into 2 groups: 1) those treated with CRF and 2) those treated with ORIF. The outcome variables were length of hospital stay, duration of anesthesia, and time in operating room. The charge for primary fracture treatment included the fees for the operation and hospitalization without any complications. Within the group of 85 patients treated for mandibular fractures in 1993, 10 patients treated with CRF and 10 patients treated with ORIF were randomly selected, and hospital billing statements were used to estimate the average charge of primary treatment. The average charge to manage a major postoperative infection also was estimated based on the billing statements of 10 randomly selected patients treated in 1992 (5 treated with CRF, 5 with ORIF) who required hospital admission for the management of a complication. The average total charge was computed by using the average charge for primary treatment plus the incidence of postoperative infection multiplied by the average charge for management of that complication., Results: Eighty-five patients were included in the study. The average charge for primary treatment was $10,100 for the CRF group and $28,362 for the ORIF group. The average charge for the inpatient management of a major postoperative infection was $26,671 for the CRF group and $39,213 for the ORIF group. The average total charge for management of a mandible fracture with CRF was $10,927; the total charge for the ORIF group was $34,636., Conclusion: The results of this retrospective study suggest that the use of CRF in the management of mandibular fractures at our institution provides considerable savings over treatment by using ORIF. The use of ORIF should be reserved for patients and fracture types with specific indications.