Management of giant cell lesions.
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Bone Density Conservation Agents↗
Biomedical subjects
L B Kaban
Publications and source records attributed to L B Kaban.
Pediatric facial fractures: recent advances in prevention, diagnosis and management.
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.
Bone Transplantation↗
Pediatric facial fractures: recent advances in prevention, diagnosis and management.
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.
Adolescent↗
Histology of the porcine mandibular distraction wound.
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.
Analysis of Variance↗
Assessment of bone formation in a porcine mandibular distraction wound by computed tomography.
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%.
Animals↗
Correlation of biomechanical stiffness with plain radiographic and ultrasound data in an experimental mandibular distraction wound.
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.
Animals↗
Development of a mechanical testing system for a mandibular distraction wound.
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.
Animals↗
Biomedical technology revolution: opportunities and challenges for oral and maxillofacial surgeons.
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.'
Adult↗
IGF-I, TGF-beta, and BMP-4 are expressed during distraction osteogenesis of the pig mandible.
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.
Animals↗
Development of a three-dimensional treatment planning system based on computed tomographic data.
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.
Algorithms↗
Proliferation of masseter myocytes after distraction osteogenesis of the porcine mandible.
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.
Animals↗
Endoscopic approach to the ramus/condyle unit: Clinical applications.
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.
Adolescent↗
Taste perception after lingual nerve repair.
PURPOSE: This retrospective study evaluates patients' perception of taste after lingual nerve injury and repair. It is hypothesized that return of taste is a distinct neurophysiologic phenomenon related to specialized taste physiology and it does not correlate with specific, objective sensory return. PATIENTS AND METHODS: During 1995 to 1996, 30 patients underwent microsurgical repair of lingual nerve injuries. Of these, 22 patients met the inclusion criteria for this study. Chart review documented the date and cause of injury, sensory examination, injury classification, procedures, operative findings, and postoperative sensory examination. A telephone questionnaire addressed whole mouth taste perception with normal daily eating. The questions asked were: 1) Was your sense of taste changed or abnormal after your nerve injury? and 2) Did your sense of taste recover after nerve repair? RESULTS: All patients had a postinjury, prerepair sensory deficit on levels A, B, and C testing: neurotmesis (n = 14); and axonotmesis (n = 8). The mean time from injury to repair was 16 weeks (range, 3 to 41 weeks). Operative findings confirmed 12 Sunderland Class IV (partial transection) injuries and 10 Class V (complete transection) injuries. All patients had primary microsurgical repair without a nerve graft or entubulization. Postoperatively, 18 patients showed marked improvement in sensory testing at levels A, B and C, and 4 patients showed no significant change. A telephone interview regarding whole mouth taste perception indicated that 20 of 22 patients perceived changed, abnormal taste postinjury and pre-repair. Two patients reported normal taste perception. Postrepair, only 7 of 20 patients reported an increase or return of taste perception to a more normal level. The mean follow-up time was 80 weeks. CONCLUSION: Most patients (20 of 22) with lingual nerve injuries in this study perceived whole mouth taste as abnormal. After nerve repair, although 82% (18 of 22) of patients had improvement in somatosensory function, whole mouth taste was perceived as improved by only 35% (7 of 20). It is proposed that the perception of whole mouth taste may not be related to the ability to perceive multiple sensory modalities, but rather to special sensory (taste) modality perception. Also, central changes may occur in the special sensory fibers that impact on the brainstem nucleus for taste (nucleus solitarius) and therefore the patient's perception of taste.
Cranial Nerve Injuries↗
Effects of latency and rate on bone formation in a porcine mandibular distraction model.
PURPOSE: Long treatment protocols currently limit the application of distraction osteogenesis (DO). The purpose of this study was to develop a porcine model for DO and to define the effects of latency and distraction rate on bone formation. MATERIALS AND METHODS: Distractors were placed through submandibular incisions. For analysis of latency, mandibular osteotomies were distracted after 0 (n = 3) or 4 (n = 2) days at a rate of 1 mm/d (7 days) with 14 days fixation. For analysis of rate, osteotomies were distracted at 1 mm (n = 4), 2 mm (n = 4), or 4 mm (n = 4) per day to produce a 12-mm gap with 24 days fixation. DO wounds were assessed in vivo with bimanual palpation to detect mobility across the gap. Harvested specimens were evaluated by gross appearance and bimanual palpation. Standardized radiographic techniques were used to estimate bone density. RESULTS: During DO, animals showed normal activity. There were no infections, and no distractors were removed prematurely. Clinical and radiographic evaluation of the groups that underwent distraction after 0- or 4-day latency showed equivalent healing. In the comparison of distraction rates, stability was greatest in the group distracted at 1 mm/d. CONCLUSIONS: A porcine model for mandibular DO has been developed in which mandibular lengthening was successfully performed without latency and at a rate of 1 mm/d. The relationships among latency, gap size, rate, and duration of fixation are poorly understood and can be defined with relevant animal models.
Animals↗
Special considerations for the pediatric emergency patient.
Management of pediatric maxillofacial infections and trauma continue to challenge the clinician, because both conditions are uncommon. Therefore, individual clinicians might not see enough cases to formulate systematic and consistent treatment plans. When one is evaluating pediatric maxillofacial infections, the location of infection (upper or lower face) can serve as a diagnostic aid to develop a differential diagnosis and to initiate empiric treatment. When evaluating pediatric maxillofacial injuries while implementing acute treatment measures, the clinician should also be aware of the potential for late adverse sequalae owing to alteration of growth. In the absence of controlled studies, however, growth alternation from traumatic injuries to the facial skeletal remains a plausible but unproved hypothesis.
Child↗
A financial analysis of maxillomandibular fixation versus rigid internal fixation for treatment of mandibular fractures.
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.
Adult↗
Differentiation of odontogenic keratocysts from nonkeratinizing cysts by use of fine-needle aspiration biopsy and cytokeratin-10 staining.
PURPOSE: In this study, the efficacy of fine-needle aspiration biopsy (FNAB) and cytokeratin 10 immunocytochemical staining to differentiate odontogenic keratocysts (OKC) from dentigerous and other nonkeratinizing cysts was evaluated. PATIENTS AND METHODS: This was a prospective study of 18 FNABs of odontogenic cystic lesions performed at the Massachusetts General Hospital between 1995 and 1998. A consistent and standardized technique was used to obtain the cytologic material. Immunocytochemistry was performed on destained smears by using a monoclonal antibody against cytokeratin 10. Identical immunohistochemical methods were applied to the final surgical specimen, and results were compared. RESULTS: Cells of 10 of 18 FNABs showed a markedly positive immunoreaction to anti-cytokeratin 10, supporting a diagnosis of OKC. In all 10 cases, the diagnosis was confirmed by histology. Six of 18 cases showed an absence of staining and were interpreted as anti-cytokeratin 10 negative. In the 2 remaining cases, there were occasional squamous cells on the smear with weak anti-cytokeratin 10 uptake. The overall pattern was negative, and these were interpreted as nonkeratinizing cysts. In all 8 of these cases, the diagnosis of OKC was excluded based on the immunocytochemistry, and the final histologic diagnoses were: dentigerous cyst (n = 4) and radicular cyst (n = 4). CONCLUSIONS: The combination of FNAB with immunocytochemical determination of cytokeratin 10 expression by sampled epithelial cells was 100% accurate in distinguishing an OKC from a nonkeratinizing odontogenic cyst in this series. The technique allows for early diagnosis and rational surgical planning.
Antibodies, Monoclonal↗
Progression of facial asymmetry in hemifacial microsomia.
Hemifacial microsomia is a common craniofacial anomaly, variably affecting structures derived from the first and second pharyngeal arches. Correction of the skeletal deformity in children has been advocated to improve growth potential and reduce secondary deformity. However, contrary reports have suggested that facial asymmetry in hemifacial microsomia does not increase with growth; therefore, skeletal correction can be postponed, even until adolescence. The purpose of this study was to test the hypothesis that facial asymmetry in hemifacial microsomia is progressive. This is a retrospective evaluation of 67 patients with untreated hemifacial microsomia. The patients were categorized as: group I (mandible type I, IIa), n = 38, and group II (mandible type IIb, III), n = 29. Pretreatment posterior-anterior cephalometric radiographs were used to analyze asymmetry by measuring the angle between the true horizontal and the following planes: piriform rim, maxillary occlusal plane, and intergonial angle. Angular measurements were averaged for patients in the deciduous (<6 years), mixed (> or =6<13 years), and permanent dentition (> or =13 years). In group I, angle piriform rim, maxillary occlusal plane, and intergonial angle increased from 7.0, 4.3, and 4.4 to 8.4, 6.6, and 6.1 degrees, respectively [mean age, 4.1 (deciduous) to 8.6 (mixed) to 21.0 (permanent) years]. In group II, angle piriform rim, maxillary occlusal plane, and intergonial angle increased from 9.5, 6.2, and 5.3 to 11.7, 7.6, and 8.0 degrees, respectively [mean age, 3.4 (deciduous) to 8.0 (mixed) years]. These data demonstrate that hemifacial microsomia is progressive and underscores the importance of early surgical correction of mandibular asymmetry in this disorder.
Adolescent↗