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Biomedical subjects

C R Forrest

Publications and source records attributed to C R Forrest.

At least 19 recordsLinked to original sources
PubMed2002

Tuberous sclerosis: clinicopathologic features and review of the literature.

INTRODUCTION: Tuberous sclerosis is a hamartoneoplastic syndrome, which may involve multiple organ systems. Oral hard tissue manifestations of the syndrome have been described in the literature only as recently as 1955. Patients who presented with clinical manifestations of tuberous sclerosis did not routinely undergo oral surveys to rule out 'lesions', and consequently data on 'lesions' in the maxillofacial complex is scant. Ten cases have been found in the English language literature, which describe maxillofacial 'lesions', which may be tumours, new growths, neoplasms or overgrowths occurring in patients diagnosed with tuberous sclerosis. PURPOSE: To review the literature for all maxillofacial lesions associated with tuberous sclerosis and to present an eleventh case of a patient with a maxillofacial lesion diagnosed as having tuberous sclerosis. RESULTS: Eleven cases were found with maxillofacial fibroblastic lesions associated with tuberous sclerosis. These lesions were all fibrous benign neoplasms found in the maxillofacial bony complex. CONCLUSIONS: Maxillofacial fibroblastic lesions in tuberous sclerosis have various histopathological presentations, some of which may be difficult to differentiate. Consequently, close microscopic examination of these lesions is necessary so that adequate surgical treatment is provided.

Child, Preschool↗
PubMed2001

Trigonomicrocephaly, severe micrognathia, large ears, atrioventricular septal defect, symmetrical cutaneous syndactyly of hands and feet, and multiple café-au-lait spots: new acrocraniofacial dysostosis syndrome?

We report on a patient with a unique constellation of anomalies comprising trigonomicrocephaly, asymmetric severe micrognathia, large ears, atrioventricular septal defect, vertebral anomalies, bilateral cutaneous syndactyly of fingers and toes, unilateral cryptorchidism and multiple café-au-lait spots. The mother of the propositus has multiple café-au-lait spots. Search of POSSUM and the London Dysmorphology Database (LDDB) uncovered no similar case. We think that this patient represents a new acrocraniofacial dysostosis syndrome.

Abnormalities, Multiple↗
PubMed2001

Use of a mechanical leech in a reverse-flow radial forearm flap: case report.

The reverse-flow radial forearm flap provides excellent coverage for distal upper-limb defects. It is simply raised and does not require microsurgical skills. However, since its vascular pedicle is reversed, its venous outflow can be significantly diminished because of the venous valves. The authors present the case of a 16-year-old patient with a sagittal amputation of the radial aspect of the right thumb, who manifested at the time of surgery marked venous engorgement of a reverse-flow radial forearm flap. This was successfully relieved by the placement of a mechanical leech consisting of a Silastic rubber catheter--of the kind used to gain central vascular access in newborns--introduced in the lumen of the reversed vein at the extremity of the flap. This permitted intermittent evacuation of blood from the flap postoperatively, contributing to the success of this procedure. The technique used is detailed and pertinent literature is reviewed.

Adolescent↗
PubMed2001

Postoperative infections in craniofacial reconstructive procedures.

The rate of, and possible risk factors for, postoperative craniofacial infection is unclear. To investigate this problem, we reviewed 349 cases of craniofacial skeletal procedures performed from 1996 to 1999 at our institution. Infection rate was determined and correlated with the use of implants, operative site, and cause of deformity. The inclusion criteria consisted of all procedures requiring autologous or prosthetic implantation in craniofacial skeletal sites, as well as all procedures involving bone or cartilage resection, osteotomies, debridement, reduction and/or fixation. Procedures that did not involve bone or cartilage surgery were excluded. The criteria for diagnosis of infection included clinical confirmation and one or more of 1) intravenous or oral antibiotic treatment outside of the prophylactic surgical regimen; 2) surgical intervention for drainage, irrigation, and or debridement; and 3) microbiological confirmation. Among the 280 surgical cases that fit the inclusion criteria and had complete records, there were 23 cases of postoperative infection (8.2%). The most common site for postoperative infection was the mandible (infection rate = 16.7%). Multiple logistic regression analysis revealed gunshot wound to be the most significant predictor of postoperative infection. Additionally, porous polyethylene implantation through a transoral route was correlated with a significant risk of postoperative infection.

Adult↗
PubMed2001

Surface anatomy of the face in Down's syndrome: linear and angular measurements in the craniofacial regions.

Measurements (23 projective linear, 2 angular) taken in the 6 craniofacial regions of 127 patients with Down's syndrome showed that 63.1% (1,836 of 2,908) were within normal limits and 36.9% (1,072) were outside them. Abnormal measurements were subnormal in 90.8% (973) and supernormal in 9.2% (99). All statistical summaries were based on z scores (adjusting for age and sex differences) classified into a small number of ranges to yield a simplified frequency distribution for each measurement. The purpose of the study was to identify the measurements closest to normal and those indicating the most severe degrees of sub- or supernormality. Approximately a quarter of normal measurements were classified as optimal, and half the subnormal or supernormal measurements were classified as severe. Intercanthal width had the highest frequency of optimal measurements (93.7%, 119 of 127), head circumference the smallest (28.6%, 36 of 126). Knowledge of the frequency of extreme abnormalities in the craniofacial regions will help during visual examination of patients with Down's syndrome. This study found the highest percentage of severely subnormal measurements in the orbital region (57.8%, 74 of 128) and the smallest in the labio-oral region (32.7%, 16 of 49). The measurement with the highest proportion of severely subnormal to all subnormal values was the palpebral fissure length (68%, 51 of 75), and the nose width had the smallest proportion (14.3%, 1 of 7).

Adolescent↗
PubMed2001

Surface anatomy of the face in Down's syndrome: anthropometric proportion indices in the craniofacial regions.

The objective of the study was to identify the proportions closest to normal and those indicating mild-to-moderate and severe degrees of disproportion. Eight proportion indices were analyzed in five craniofacial regions of 125 Down's syndrome patients, based on a total of 985 data points. More than two thirds of the patients fell within the normal range, although more than one quarter were abnormal (disproportionate). All statistical summaries were based on z-scores (adjusting for age and sex differences), converted into descriptive anthropometric categories to yield a simplified frequency distribution for each proportion index. Normal proportions were harmonious in 55.9% of patients. Disproportions were mild to moderate in 66.4%, severe in 33.6%. The highest frequency of harmony was found in the head (70.2%), the lowest in the orbits (40.8%). The highest percentage of mild-moderate disproportion was found in the face (79.3%). The highest percentage of severe disproportions was recorded in the intercanthal index of the orbits (44.7%) and the smallest frequency in the face (20.7%). In the five craniofacial regions among the normal proportions, harmonies were more frequent than disharmonies. Among the disproportions, the percentage of mild-moderate ones was greater than those of severe degree.

Adolescent↗
PubMed2001

Radiation-induced craniofacial bone growth inhibition: development of an animal model.

Craniofacial deformities caused by therapeutic radiation-induced bone growth inhibition can occur in up to 100% of survivors of childhood head and neck cancers. The mechanism of radiation-induced craniofacial bone growth inhibition is poorly understood. The objective of this study is to establish a model of radiation-induced craniofacial bone growth inhibition to study the pathophysiology of radiation on growing membranous bone. Seven-week-old male New Zealand white rabbits were randomized into 4 groups (n = 10/group) and received a single dose of orthovoltage radiation (0, 15, 25, or 35 Gy) to the right orbital-zygomatic complex. Serial radiographs and computed tomography scans were performed for cephalometric analysis, bone volume, and bone density measurements until skeletal maturity at 21 weeks. Statistically significant ( P < 0.05) reductions in orbital-zygomatic complex linear bone growth, bone volume, and bone density were found after radiation with 25 or 35 Gy compared with nonirradiated control animals. A significant ( P < 0.05) decrease in orbital-zygomatic complex volume was noted after 15-Gy radiation but there were no significant effects on linear bone growth as assessed by cephalometric analysis at this dose. This study establishes the rabbit orbital-zygomatic complex as a suitable model for the study of radiation-induced craniofacial bone growth inhibition and will permit investigation into the underlying cellular and molecular basis of this injury.

Analysis of Variance↗
PubMed2001

Effect of isolation of periosteum and dura on the healing of rabbit calvarial inlay bone grafts.

Little is understood about the role of the recipient site in the revascularization and incorporation of autogenous inlay bone grafts in the craniofacial skeleton. Clinical experience demonstrates that secondary complex cranial vault reconstruction performed with scarred avascular dura or poor soft-tissue coverage may undergo significant resorption, thus compromising the aesthetic outcome. This study was designed to determine the effect of isolating autogenous orthotopic inlay calvarial bone grafts from the surrounding dura and/or periosteum on graft revascularization, healing, and volume maintenance in the adult rabbit. Adult rabbits were randomized into four groups (n = 10 per group); in each rabbit, the authors created a circular, 15-mm in diameter, full-thickness cranial defect followed by reconstruction with an autogenous calvarial bone graft, which was replaced orthotopically and held with microplate fixation. Silicone sheeting (0.5 mm thickness) was used to isolate the dura (group II), the periosteum (group II), or both dura and periosteum (group IV) from the graft interface. No silicone was placed in group I. Animals were killed 10 weeks postoperatively, and calvaria were harvested to assess graft surface area, morphology, quantitative histology, fluorochrome staining, and revascularization. Grafts isolated from both the dura and periosteum exhibited significant decreases in total bone (cortical and trabecular) surface area, blood vessel count, and interface healing compared with nonisolated control grafts. Isolation of either the dura or periosteum significantly (p < 0.05) decreased blood vessel count but had no significant effect on interface healing. Isolation of the dura alone was associated with a significant (p < 0.05) decrease in graft cross-sectional surface area and dural cortical thickness compared with nonisolated control grafts, but this effect was not observed when the periosteum alone was isolated. Quantitative histology performed 10 weeks after surgery indicated that graft isolation was associated with increased marrow fibrosis and necrosis compared with nonisolated controls; it also demonstrated evidence of increased activity in bone remodeling (osteoblast and osteocyte count, new trabecular bone, and surface resorption). Triple fluorochrome staining suggested increased bone turnover in the nonisolated grafts compared with isolated grafts at 1 and 5 weeks postoperatively. This study demonstrates that isolating a rabbit calvarial inlay autogenous bone graft from the dura and/or periosteum results in significantly (p < 0.05) decreased revascularization, interface healing, and cross-sectional areas of amount of mature bone compared with nonisolated control grafts 10 weeks after surgery. At this time point, histologic examination demonstrates a paradoxical increase in bone remodeling in isolated bone grafts compared with controls. It is possible that the inhibition of revascularization results in a delayed onset of the remodeling phase of graft incorporation. However, in the model studied, it is not known whether the quantitative histologic and morphometric parameters measured in these isolated grafts exhibit a "catch-up" phenomenon at time points beyond 10 weeks after surgery. The results of this study emphasize the importance of a healthy recipient site in the healing and incorporation of calvarial bone grafts but stress the need for further investigation at later time points.

Animals↗
PubMed2001

Amplification effect and mechanism of action of ET-1 in U-46619-induced vasoconstriction in pig skin.

The aim of this study was to investigate if a low concentration of endothelin-1 (ET-1; 8 x 10(-10) M) may amplify the skin vasoconstrictor effect of other vasoactive substances in the pathogenesis of skin vasospasm. Pig skin flaps (6 x 16 cm) were perfused with Krebs buffer equilibrated with 95% O(2) and 5% CO(2) at 37 degrees C and pH 7.4. Skin perfusion pressure measured by a pressure transducer and skin perfusion assessed by the dermofluorometry technique were used for assessment of skin vasoconstriction. We observed that ET-1 (8 x 10(-10) M) significantly amplified the concentration-dependent (10(-7)-10(-5) M) skin vasoconstrictor effect of norepinephrine. More importantly, we observed for the first time that this low concentration of ET-1 also amplified the concentration-dependent (10(-8)-10(-6) M) skin vasoconstrictor effect of the thromboxane A(2) mimetic U-46619, and this amplification effect of ET-1 was completely blocked by the protein kinase C (PKC) inhibitor chelerythrine (5 x 10(-6) M). Conversely, the PKC activator phorbol 12,13-dibutyrate (10(-7) M) amplified the vasoconstrictor effect of U-46619. Furthermore, the sensitivity of the skin vasculature to the vasoconstrictor effect of extracellular Ca(2+) in U-46619-induced skin vasoconstriction was significantly enhanced in the presence of 8 x 10(-10) M ET-1. Finally, the cyclooxygenase inhibitor indomethacin (5 x 10(-6) M) did not affect the amplification effect of ET-1 on U-46619-induced skin vasoconstriction. We conclude that a low concentration of ET-1 can amplify the skin vasoconstrictor effect of U-46619 independent of endogenous cyclooxygenase products, and the mechanism may involve activation of PKC and increase in sensitivity of the contractile apparatus to Ca(2+) in smooth muscle cells.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2001

Effect of nicotine on vasoconstrictor and vasodilator responses in human skin vasculature.

Our objective was to test the hypothesis that acute exposure of human skin vasculature to nicotine may have deleterious effects on endothelial function. Vasoconstriction and vasorelaxation in isolated perfused human skin flaps (approximately 8 x 18 cm) derived from dermolipectomy specimens were assessed by studying changes in skin perfusion pressure measured by a pressure transducer, and skin perfusion was assessed by a dermofluorometry technique (n = 4 or 5). It was observed that nicotine (10(-7) M) amplified (P < 0.05) the norepinephrine (NE)-induced concentration-dependent (10(-7)-10(-5) M) increase in skin vasoconstriction compared with the control. This amplification effect of nicotine in NE-induced skin vasoconstriction was not blocked by the nicotine-receptor antagonist hexamethonium (10(-6) M) or the cyclooxygenase inhibitor indomethacin (10(-5) M). It was also observed that ACh and nitroglycerin (NTG) elicited a concentration-dependent (10(-8)-10(-5) M) vasorelaxation in skin flaps preconstricted with 8 x 10(-7) M of NE. The vasorelaxation induced by ACh was attenuated (P < 0.05) in the presence of nicotine (10(-7) M) compared with the control. However, skin vasorelaxation induced by NTG was not affected by nicotine (10(-7) M). ACh and NTG are known to induce endothelium-dependent and -independent vasorelaxation, respectively. The present findings were interpreted to indicate that acute exposure of human skin vasculature to nicotine was associated with 1) amplification of NE-induced skin vasoconstriction and 2) impairment of endothelium-dependent skin vasorelaxation. Cyclooxygenase products and nicotine receptors blocked by hexamethonium were not involved in the amplification of NE-induced skin vasoconstriction by nicotine. These findings may provide further insight into the pathogenesis of skin vasospasm in skin flap surgery and skin ischemic disease associated with cigarette smoking or use of smokeless tobacco.

Acetylcholine↗
PubMed2001

Minimally invasive approaches to mandibular fractures.

Excellence in mandibular fracture repair requires anatomic restoration of the displaced bone segments, maintenance of the reduction until bone union has been confirmed, and minimization of surgical stigmata. Repairs should ideally be cost-effective, reproducible, adaptable, and expeditiously executed. Fractures of two subregions of the mandible, the condylar neck and the symphysis, can benefit from minimally invasive surgical techniques. The use of these techniques in the mandible is reviewed.

Endoscopy↗
PubMed2000

Comparison of the morphology of the "cleft face" and the normal face: defining the anthropometric differences.

Morphological characteristics of the "cleft face" were analyzed by calculating proportion indices in young adults who had undergone surgery in childhood for cleft lip and/or palate: 592 in 37 subjects with unilateral clefts and 432 in 27 with bilateral clefts. Three areas of the face with 16 indices based on 12 projective linear measurements were analyzed in each subject: 5 indices in the general face, 6 in the upper face, and 5 in the lower. Although a balanced relationship was found in two thirds of the indices assessed, severe disproportions, which greatly influence appearance, were noted in about one quarter. In the general face, the most frequent abnormal anthropometric findings contributing to severe disproportions were small upper-face height and a severely high or moderately narrow mandible. In the soft tissues, disproportions included wide nose, small nasal tip protrusion, and short or long columella. Deviations from normality were rarely noted in the nose and upper-lip height, mouth width, total facial height, and width of the upper face. In the upper face, severe disproportions occurred much more frequently in bilateral cleft subjects (67.6%) than in unilateral clefts (30.3%). In the lower face, however, severe disproportions were twice as frequent among unilateral clefts (39.4%) than bilateral (14.7%). The results, although interesting, require complementary preoperative data for reliable analysis of the adult "cleft face."

Adolescent↗
PubMed2000

The vascularized pig fibula bone flap model: effect of segmental osteotomies and internal fixation on blood flow.

The free fibular flap is the flap of choice for reconstruction of complex mandibular defects, although two or more osteotomies may be required to recreate the normal mandibular contour. The effect of these surgical manipulations on the fibula has not been adequately investigated. This study was designed to study the effect of multiple segmental osteotomies and internal fixation techniques on blood flow in the vascularized pig fibula bone flap model. The hindlimbs of 15 Yorkshire pigs were randomized into 1 of 5 groups (n = 6 fibulae per group) consisting of: (1) a nonoperated, in situ fibula; (2) an elevated fibula flap; (3) an elevated fibula flap with two segmental osteotomies; (4) an elevated fibula with two segmental closing osteotomies rigidly fixed with 2-mm miniplates; (5) an elevated fibula with two segmental closing osteotomies rigidly fixed with 2-mm lag screws. Total and gradient blood flow was measured in the bone and soft-tissue components of these flaps using the 15-microm radioactive microsphere technique. The creation of two segmental osteotomies in the vascularized pig fibula bone flap model resulted in a significant decrease (p<0.05) in the gradient blood flow in the segment of bone distal to the second osteotomy. Application of miniplates or lag screws across closing osteotomies resulted in a significant decrease (p<0.05) in total and gradient blood flow to the bone component of the fibulae, as compared with the elevated and osteotomized fibulae groups. An increase in blood flow suggesting a hyperemic response was noted in the bone and soft tissue in the elevated and osteotomized flap groups as compared with the in situ, nonoperated controls. This study established the validity of the pig fibula as a suitable model for investigating the pathophysiology of blood flow changes in the face of standard surgical maneuvers necessary for the restoration of mandibular form and function. The results demonstrated that the creation of multiple segmental osteotomies and the application of internal fixation significantly decreases (p<0.05) blood flow to the distal portion of the flap. The effects of segmental osteotomies and internal fixation on healing and growth of the pig fibula bone flap model are investigated in a separate study.

Animals↗
PubMed2000

Role and mechanism of PKC in ischemic preconditioning of pig skeletal muscle against infarction.

Protein kinase C (PKC) inhibitors, chelerythrine (Chel, 0.6 mg) and polymyxin B (Poly B, 1.0 mg), and PKC activators, phorbol 12-myristate 13-acetate (PMA, 0.05 mg) and 1-oleoyl-2-acetyl glycerol (OAG, 0.1 mg), were used as probes to investigate the role of PKC in mediation of ischemic preconditioning (IPC) of noncontracting pig latissimus dorsi (LD) muscles against infarction in vivo. These drugs were delivered to each LD muscle flap (8 x 12 cm) by 10 min of local intra-arterial infusion. It was observed that LD muscle flaps sustained 43 +/- 5% infarction when subjected to 4 h of global ischemia and 24 h of reperfusion. IPC with three cycles of 10 min ischemia-reperfusion reduced muscle infarction to 25 +/- 3% (P < 0.05). This anti-infarction effect of IPC was blocked by Chel (42 +/- 7%) and Poly B (37 +/- 2%) and mimicked by PMA (19 +/- 10%) and OAG (14 +/- 5%) treatments (P < 0.05), given 10 min before 4 h of ischemia. In addition, the ATP-sensitive K(+) (K(ATP)) channel antagonist sodium 5-hydroxydecanoate attenuated (P < 0.05) the anti-infarction effect of IPC (37 +/- 2%), PMA (44 +/- 17%), and OAG (46 +/- 9%). IPC, OAG, and Chel treatment alone did not affect mean arterial blood pressure or muscle blood flow assessed by 15-microm radioactive microspheres. Western blot analysis of muscle biopsies obtained before (baseline) and after IPC demonstrated seven cytosol-associated isoforms, with nPKCepsilon alone demonstrating progressive cytosol-to-membrane translocation within 10 min after the final ischemia period of IPC. Using differential fractionation, it was observed that nPKCepsilon translocated to a membrane compartment other than the sarcolemma and/or sarcoplasmic reticulum. Furthermore, IPC and preischemic OAG but not postischemic OAG treatment reduced (P < 0.05) muscle myeloperoxidase activity compared with time-matched ischemic controls during 16 h of reperfusion after 4 h of ischemia. Taken together, these observations indicate that PKC plays a central role in the anti-infarction effect of IPC in pig LD muscles, most likely through a PKC-K(ATP) channel-linked signal-transduction pathway.

Adenosine↗
PubMed1999

A biomechanical analysis of the orbitozygomatic complex in human cadavers: examination of load sharing and failure patterns following fixation with titanium and bioresorbable plating systems.

The orbitozygomatic complex (OZC) and zygomatic arch act as key buttresses in the restoration of midfacial projection and width in the treatment of panfacial fractures, yet little is known about the biomechanical and deformational forces placed on this region under applied load conditions. The aims of this project were (1) to study the stress-force relationships and load sharing of the intact human OZC under subfailure loads, (2) to assess load sharing and breaking strength of the OZC when intact and after four-point miniplate fixation with either titanium (1.2 and 1.7 mm) or bioresorbable (1.5 and 2.0 mm) systems, and (3) to analyze failure patterns. Using the MTS machine, fresh frozen human skulls stripped of soft tissue underwent loading with subfailure and failure forces directed in a standard fashion. Electrical resistance gauges applied directly to local and remote bony buttresses demonstrated temporary deformation at local (zygomatic arch, lateral and inferior orbital rim) and remote (supraorbital rim) buttresses under subfailure loading conditions. Breaking strength of the OZC (N = 10) measured before and after four-point application of 1.2- or 1.7-mm titanium or 1.5- or 2.0-mm bioresorbable miniplates demonstrated a significant (p < 0.05) decrease compared with intact controls. Surprisingly, the 2.0-mm bioresorbable miniplate construct provided only 13% of the intact breaking strength of the OZC compared with 39% for the 1.7-mm titanium system (p < 0.05). Plate bending or breakage was responsible for failure of the OZC following rigid fixation. Biomechanical testing of the OZC demonstrates (1) load sharing at regional and remote bony buttresses, (2) significant decreases in breaking strength following miniplate fixation, and (3) deformation of miniplates as a primary cause of failure under load conditions. Data generated from this project may be useful with regard to optimizing fixation of the OZC in the context and treatment of panfacial fractures.

Absorbable Implants↗
PubMed1999

The vascularized pig fibula bone flap model: effects of multiple segmental osteotomies on growth and viability.

Previous work by this laboratory introduced the pig fibula bone flap as a model for the study of the pathophysiology of vascularized bone flaps. Anatomic and hemodynamic studies demonstrated a significant (p < 0.05) decrease in vascular perfusion after a series of segmental osteotomies and rigid fixation (lag screws and miniplates) in the distal end of the flap, suggesting that blood flow to the distal osteotomized segment of the flap may be impaired. Killing the animals after blood flow studies precluded assessment of the effect of these hemodynamic changes on bone healing. Therefore, the aim of this study was to assess the pig fibula bone flap model with respect to viability, healing, and subsequent growth after multiple segmental osteotomies and rigid fixation to contribute to the understanding of vascularized bone flap pathophysiology. Yorkshire pigs (20 to 25 kg) were used for all experiments. Eight pigs underwent unilateral elevation of a vascularized fibula bone flap, which was osteotomized into three segments and orthotopically rigidly fixed using a 2.4-mm mandibular reconstruction plate. The left fibula remained as the control. Fluorochrome labels were injected to assess bone viability and turnover, and both fibulae were assessed for growth radiologically. The fibulae were harvested 21 days postoperatively (when the animals were killed), and bone healing was assessed histologically and clinically. There were no significant differences in preoperative and postoperative lengths of the osteotomized fibulae compared with the controls, suggesting that there was no impairment of growth potential after multiple segmental osteotomies and rigid fixation. Significant (p < 0.05) bony hypertrophy of the osteotomized fibulae was noted when compared with controls. Mobility was observed in 3 of the 32 osteotomies (9 percent), occurring across one proximal and two distal osteotomies in association with failure of fixation. However, histologic and fluorochrome assessment confirmed the viability of all bone segments, as supported by the presence of tetracycline given 2 days postoperatively. The pig fibula bone flap model is well tolerated by the pig. Multiple segmental osteotomies and rigid fixation, previously associated with a significant decrease in blood flow in the distal segment, did not impair either growth potential, viability, or healing ability. It is suggested that the pig fibula is a suitable model for the study of bone flap pathophysiology.

Animals↗
PubMed1999

Application of minimal-access techniques in lag screw fixation of fractures of the anterior mandible.

A modification of the traditional open methods for the surgical management of anterior mandibular fractures using the principles of minimal-access surgery is presented; it was successfully performed in five patients. This technique incorporates the use of lag screws introduced through small incisions transmucosally or percutaneously after anatomic reduction of the fracture, and it relies on accurate preoperative radiologic assessment of the fracture pattern and location. This technique is indicated for any favorable fracture in the anterior mandibular arch that could achieve osteosynthesis with lag screw fixation, and it depends on the use of a dental arch bar as a tension band. Contraindications include unfavorable fracture patterns (long oblique, comminuted, or flat mandibular plane), inadequate dental support to maintain an arch bar due to missing or loose teeth, the inability to determine the fracture pattern preoperatively, and operator inexperience. Potential advantages include a shorter operative time, economic savings, decreased patient morbidity (swelling, scarring, and mental nerve and lower-lip muscle dysfunction), and improvement in functional rehabilitation.

Adult↗