The Association of Body Mass Index and Early Outcomes Following Orthognathic Surgery.

BACKGROUND: The existing data on the link between body mass index (BMI), operative characteristics, and surgical outcomes across orthognathic surgery are limited. PURPOSE: The purpose was to measure the association between BMI and early postoperative outcomes in orthognathic surgery. STUDY DESIGN, SETTING, AND SAMPLE: This is a retrospective cohort study of patients (n = 118) aged > 14 years undergoing bimaxillary orthognathic surgery between 2015 and 2018 by a single surgeon within the Kaiser Permanente Northern California-integrated healthcare system. Patients undergoing unilateral or additional procedures, history of prior orthognathic surgery, or pre-existing pain conditions were excluded. PREDICTOR VARIABLE: The predictor variable was BMI measured as a continuous (kg/m2) and categorical variable (underweight/normal, overweight, obese). MAIN OUTCOME VARIABLE(S): The primary outcome variables were additional postoperative antibiotics, increased postoperative visits, wound dehiscence, and wound infection. The secondary outcome variables were total operative and anesthesia time. COVARIATES: The demographic covariates included age, sex, and race/ethnicity. The clinical covariates included history of obstructive sleep apnea, Mallampati score, tobacco use, American Society of Anesthesia classification, thyromental distance, history of difficult intubation, and Angle's classification. ANALYSES: Bivariate and multivariate analyses were performed to measure the associations between BMI and the primary and secondary outcomes. Multivariable logistic regression analyses were used to measure associations between BMI and the postoperative outcomes. Statistical significance was defined as P < .05. RESULTS: The study sample was composed of 118 subjects with a mean age of 26.91 years (standard deviation 9.43). Forty-seven percent (n = 55) were male, and the mean BMI was 25.13 (standard deviation 5.19). BMI category was significantly associated with age, with increasing age associated with higher BMI category (P = .02). According to the bivariate and multivariable logistic regression analyses, controlling for age, race/ethnicity, BMI, and total operative time, increased total operative time was associated with additional postoperative antibiotics (odds ratio = 1.03, 95% confidence interval: 1.01, 1.05), and increased postoperative appointments (odds ratio = 1.02, 95% confidence interval: 1.01, 1.04). No significant association between BMI and other clinical or operative characteristics was seen aside from American Society of Anesthesia classification. CONCLUSION AND RELEVANCE: Elevated BMI was not associated with worsened operative characteristics or postoperative outcomes. This supports the suitability of orthognathic surgery in a BMI-diverse population.

Role of computed tomographic angiography in treatment of patients with temporomandibular joint ankylosis.

PURPOSE: To evaluate the use of preoperative computed tomographic angiography (CTA) and selective embolization as an ancillary tool for the treatment of patients with temporomandibular joint (TMJ) ankylosis. MATERIALS AND METHODS: The present study was a case series of subjects with bilateral TMJ ankylosis who had undergone preoperative CTA and surgical release with immediate reconstruction. The indications for CTA were either an intimate association between the vessels and the ankylotic mass on the facial computed tomography (CT) scan or a history of multiple previous TMJ operations. In cases in which intimate anatomic association was present between the branches of the maxillary artery and the ankylotic masses, preoperative selective embolization was performed. All subjects underwent a standard approach to ankylosis release with immediate reconstruction and were followed up for up to 6 months postoperatively. The demographic and operative variables were recorded for each subject. RESULTS: Five subjects (mean age, 36.4 years; 3 females) with bilateral TMJ ankylosis underwent release and had undergone preoperative CTA for vascular assessment. Three subjects underwent preoperative embolization. The total operating time ranged from 5.9 to 10.3 hours. The intraoperative blood loss ranged from 150 to 3,750 mL. One patient who had undergone unilateral embolization required an intraoperative transfusion because of bleeding on the nonembolized side. No adverse cardiac, renal, or neurologic events developed secondary to the blood loss. In all 5 subjects, the preoperative maximal incisor opening was less than 15 mm, increased to more than 35 mm intraoperatively, and was 30 mm or more at 6 months or longer of follow-up. CONCLUSIONS: In select cases, CTA can be a useful adjunct in the treatment of patients with TMJ ankylosis.

Neuropathic pain following sagittal split ramus osteotomy of the mandible: prevalence, risk factors, and clinical course.

PURPOSE: To estimate the prevalence of, risk factors for, and clinical course of neuropathic pain (NPP) after sagittal split ramus osteotomy (SSRO) of the mandible in a large cohort of patients. MATERIALS AND METHODS: A retrospective cohort of all patients who underwent SSRO at 2 medical centers within Kaiser Permanente Northern California from January 2007 through September 2012 was assembled. Demographic, clinical, and surgical factors were abstracted from medical records and relevant comorbidities were identified. The prevalence of NPP in the cohort was calculated and the clinical signs, symptoms, temporal characteristics, and treatment response in affected patients were noted. RESULTS: The authors identified 1,778 patients who underwent SSRO and excluded 107 patients according to predefined criteria. The remaining 1,671 patients had a median age of 24 years (interquartile range, 19 to 35 yr) and 62.4% were women. Seven patients developed NPP after SSRO, which was an overall prevalence of 0.42%. All patients with NPP in this cohort were women and had a median age of 49 years. The risk factors for developing NPP after this surgery were older age (P = .0098), depression (P = .0100), and female gender. NPP developed an average of 30 days postoperatively (range, 18 to 56 days) and persisted for a median duration of 52 days (range, 30 to 69.5 days). All patients responded favorably to anticonvulsant (n = 6) or tricyclic (n = 1) medications, and no patients developed chronic postsurgical pain. CONCLUSIONS: NPP was an infrequent complication after SSRO, occurring in 1 of 238 patients in this cohort. The short duration and positive response to medication are reassuring findings. The results of this investigation highlight the need for prospective studies to further understand the spectrum of postoperative NPP.

Serial histologic and immunohistochemical changes in anterior digastric myocytes in response to distraction osteogenesis.

PURPOSE: To document histologic and immunohistochemical changes in the anterior digastric muscle during distraction osteogenesis (DO). MATERIALS AND METHODS: Nineteen Yucatan minipigs with mixed dentition were used for these experiments. Group A (n = 16) underwent unilateral mandibular distraction at a rate of 1 mm/day (no latency) for 12 days. Animals were killed at mid-DO (n = 5), end-DO (n = 5), mid-fixation (n = 4), and end-fixation (n = 2). Group B (n = 2) underwent acute 12-mm advancement, and group C (n = 1) dissection and osteotomy. Animals from groups B and C were killed at the end-DO time point. Digastric muscles from treatment and contralateral sides of all animals were harvested and embedded in paraffin. Specimens were stained with hematoxylin/eosin or immunohistochemically for proliferating cell nuclear antigen (PCNA; total cell proliferation), paired Box-7 gene protein (Pax7; satellite cells), or myogenic differentiation 1 protein (MyoD; differentiating myoblasts). Descriptive and bivariate statistics were computed to compare groups (P ≤ .05 statistically significant). RESULTS: All animals survived the operation and observation period; there were no device failures. Two animals (1 at mid-DO, 1 at mid-fixation) were eliminated from the study because of postoperative infection. There was minimal digastric inflammation, fibrosis, and muscle fiber size variability during active DO. Immunohistochemical analysis showed statistically significant increases in PCNA (cellular proliferation), Pax7 (satellite cells), and MyoD (differentiating myoblasts) positive nuclei in digastrics at mid-DO and end-DO. CONCLUSIONS: Results of this study indicate that there are minimal pathologic changes but significant increases in PCNA, Pax7, and MyoD positive nuclei during active distraction. This supports the hypothesis that the digastric muscle response to DO consists of proliferation and hypertrophy.

Histomorphometric analysis of the porcine mandibular distraction wound.

PURPOSE: To analyze the sequence of histomorphometric changes in the regenerate during distraction osteogenesis (DO) of the minipig mandible. MATERIALS AND METHODS: A total of 16 minipigs underwent unilateral mandibular DO using a protocol of 0-day latency and a 1-mm/day rate for 12 days, and 24 days of fixation. The mandibles were harvested at mid-DO, end-DO, mid-fixation, and end-fixation. An additional 2 minipigs underwent acute lengthening, and 1 sham control was included. Serial gross examinations and plain radiographs were performed before paraffin embedding. The sections were stained with hematoxylin-eosin or hematoxylin/alcian blue/sirius red stain. Histomorphometric analysis was performed to determine the percentage of surface area (PSA) occupied by hematoma, fibrous tissue, cartilage, and bone. RESULTS: All 19 minipigs survived the operation, and 17 survived the observation period; 2 were killed because of infection (mid-DO, n = 1 and end-fixation, n = 1). No device failures occurred. Of the 17 specimens, 4 were at mid-DO, 4 at end-DO, 4 at mid-fixation, and 2 at end-fixation; 2 were in the acute lengthening group, and 1 was the sham control. Hematoma was present only at mid-DO (16.61 +/- 8.07 PSA) and end-DO (1.17 +/- 2.33 PSA). Fibrous tissue decreased from mid-DO (53.12 +/- 8.59 PSA) to end-fixation (25.00 +/- 0.83 PSA). Cartilage was present in end-DO (1.72 +/- 2.71 PSA), mid-fixation (5.82 +/- 6.64 PSA), and acute lengthening (1.43 +/- 0.95 PSA). Bone increased from mid-DO (25.18 +/- 0.99 PSA) to end-fixation (64.89 +/- 0.79 PSA) and occurred earlier in the superior and middle thirds of the wounds. Periosteal bone formation predominated over endosteal bone formation early in distraction. CONCLUSION: The results of the present study indicate that bone formation in this model consists of both intramembranous and endochondral components, with intramembranous osteogenesis predominating. Bone formation occurred earlier in the superior/middle portions of the wound, possibly owing to osteoinductive properties of developing tooth buds and the inferior alveolar nerve, respectively.

Condylectomy and costochondral graft reconstruction for treatment of active idiopathic condylar resorption.

PURPOSE: The purpose of this study was to evaluate the outcomes in patients with active bilateral idiopathic condylar resorption treated by condylectomy and costochondral graft (CCG) reconstruction. PATIENTS AND METHODS: This was a retrospective evaluation of 15 consecutive patients treated at Massachusetts General Hospital from 1999 to 2004 who had: 1) active bilateral idiopathic condylar resorption confirmed by clinical examination, plain radiographs, and technetium-99 bone scan; 2) adequate documentation; and 3) a minimum of 12 months follow-up. Patients with an identifiable cause of condylar resorption such as rheumatoid or degenerative arthritis, trauma, or steroid use, or who had less than 12 months follow-up were excluded. Preoperative, immediate postoperative, 6-month, 12-month, and latest follow-up clinical examinations, lateral cephalograms, and panoramic radiographs were used to evaluate the outcomes. Inferior alveolar and marginal mandibular nerve function, jaw motion, and occlusion were evaluated by history and physical examination. All patients underwent bilateral condylectomy and CCG reconstruction. RESULTS: There were 13 female and 2 male patients with a mean age of 24 years. Mean follow-up was 34 months (range, 12 to 84). Preoperatively, all patients had Class II malocclusion: mean overjet 6.2 mm and mean anterior open bite -2.65 mm. At latest postoperative follow-up, all patients showed Class I occlusion with no anterior open bite, a stable and reproducible occlusion, and a normal range of TMJ motion with a mean maximal incisal opening of 39 mm. CONCLUSION: The results of this study indicate that a stable and satisfactory outcome is achievable in patients with active idiopathic condylar resorption treated by condylectomy and CCG reconstruction.

Effect of interferon-alpha-2b on porcine mesenchymal stem cells.

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.

Reconstruction of mandibular defects with autologous tissue-engineered bone.

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.

Endoscopic mandibular condylectomy and reconstruction: early clinical results.

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.

Staged protocol for resection, skeletal reconstruction, and oral rehabilitation of children with jaw tumors.

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.