Biomedical subjects
Publications and source records attributed to M A Pogrel.
At a recent meeting I attended in Bournemouth there was a lot of talk about 'managed care' in medicine and dentistry arriving in the UK. Managed care has already been introduced in the US and is the subject of many passionate debates. This article reviews managed care in the US and how it has affected health care over the last few years.
BACKGROUND AND OBJECTIVE: To assess whether the gallium-aluminum-arsenide low energy laser will increase cell proliferation, cell attachment, or cell migration in cultured fibroblasts and keratinocyte models. STUDY DESIGN/MATERIALS AND METHODS: Monolayer cultures of fibroblasts and keratinocytes were subjected to gallium-aluminum-arsenide laser irradiation at varying power densities for varying time intervals. Cell proliferation was assessed by absorbent spectrophotometry while cell adhesion was assessed by a microcolorimetric assay for cells attached to bovine dermis collagen. Cell migration was assessed through a filter utilizing high power microscopic fields. RESULTS: There were no differences in cell proliferation, adhesion, or migration in either the fibroblasts or keratinocyte culture treated with the gallium-aluminum-arsenide laser at any power density or time compared with nontreated controls. CONCLUSION: The gallium-aluminum-arsenide laser, when utilized at powers 5-100 milliwatts and times of between 10-120 seconds has no biostimulatory effects on fibroblasts or keratinocyte cultures as assessed by cell proliferation, adhesion, or migration.
PURPOSE: This study tested the hypothesis that some sensory innervation to the lower incisor teeth comes from reentry of the terminal branches of the mental nerve through the labial plate of the anterior mandible. PATIENTS AND METHODS: Ten cadaveric heads (20 sides) were dissected and studied to determine whether the mental nerve crossed the midline or reentered the labial plate. Using careful dissection, the most posterior branch of the nerve was exposed from its point of emergence at the mental foramen to its insertions, and any entries into the labial plate were recorded and photographed. RESULTS: Three of 20 (15%) specimens showed unequivocal evidence of nerve reentry into the labial plate. Five specimens displayed strong evidence of nerve fibers reentering the plate, but these were too fragile to be dissected through the periosteum without breaking. In 12 of 20 (60%) specimens, there were no branches identified that reentered the bone plate. Of the eight specimens showing evidence of reentry, four had substantial midline crossover. CONCLUSIONS: The finding that branches of the mental nerve may reenter the labial plate to supply the lower incisors explains the phenomenon of crossover innervation from the contralateral mental nerve and the fact that a labial infiltration injection will anesthetize the lower incisor teeth.
PURPOSE: This study compared vascularized and nonvascularized bone grafts for the reconstruction of segmental defects of the mandible. PATIENTS AND METHODS: The results in 39 patients having vascularized bone grafts (38 fibulas and one iliac crest) and 29 patients having nonvascularized bone grafts (26 iliac crest [22 corticocancellous block grafts, four cancellous bone grafts in a tray] and three rib grafts) for segmental mandibular reconstruction were evaluated in terms of overall success rate, total number of surgeries performed, total blood loss, total number of hospital days, and total number of hours in the operating room. RESULTS: Of 39 vascularized bone grafts, two failed (95% success rate), whereas of 29 nonvascularized bone grafts, seven failed (76% success rate). Failure for the nonvascularized bone grafts was closely correlated to the length of the defect. Nonvascularized bone graft patients underwent an average of one more surgical procedure for total reconstruction than vascularized bone graft patients, including osseointegrated implants. However, vascularized bone graft patients spent a mean of over 14 additional days in the hospital for all of their reconstructive procedures and an additional 3 hours in the operating room as compared with nonvascularized bone graft patients. Blood loss was similar in both groups (1,100 mL). Only 20% to 24% of patients in each treatment group have completed reconstruction to include osseointegrated implants. CONCLUSIONS: The success rate for vascularized bone grafting is high and is the treatment of choice when primary reconstruction is required, when the patient has been previously irradiated, or when simultaneous replacement of soft tissue is required. Vascularized bone grafts are also the treatment of choice for mandibular replacements over 9 cm in length. Nonvascularized bone grafts create a better contour and bone volume for facial esthetics and subsequent implant insertion, and may be the treatment of choice for secondary reconstruction of defects less than 9 cm in length.
PURPOSE: This article discusses the cause, appropriate diagnostic evaluation, and management of progressive condylar resorption. PATIENTS AND METHODS: This retrospective study evaluated 28 adult patients with bilateral progressive condylar resorption. Investigation included serial clinical examination, lateral cephalograms, tomograms, and a technetium isotope bone scan when indicated. Twenty-two patients were managed by either condylectomy and reconstruction with a costochondral graft (n = 5 patients) or orthognathic surgery (n = 18 patients). One patient initially had orthognathic surgery and subsequently underwent condylectomy and costochondral grafting, making a total of 23 procedures on 22 patients. Six patients received no surgical treatment. All patients were observed at least 2 years postoperatively. RESULTS: Of the 18 patients who underwent orthognathic surgery, four again demonstrated condylar resorption with recurrence of open bite and retrognathism. Four patients had a stable result, but currently have temporomandibular joint (TMJ) symptoms, whereas 10 patients had a stable result (no change in postoperative occlusion or jaw position) without TMJ symptoms. The five cases receiving condylectomy and costochondral grafting were stable and asymptomatic, with good mandibular function. Analysis of the 18 orthognathic surgery patients showed that relapse occurred in patients having bimaxillary surgery with mandibular advancements greater than 5 mm and with a preoperative posterior ramus height of less than 35 mm. CONCLUSION: The management of progressive condylar resorption remains controversial. Orthognathic surgery in this small sample was associated with a complication rate (relapse or TMJ dysfunction) of approximately 45% (8 of 18). In contrast, condylectomy and costochondral grafting appeared to produce stable and functional results. Further long-term outcome studies for patients with condylar resorption are needed to corroborate these results.
PURPOSE: The purpose of this study was to determine the efficacy of vascularized free fibula bone grafts for mandibular salvage reconstruction. PATIENTS AND METHODS: Seven patients had fibula grafts after failed attempts at mandibular reconstruction. The prior attempts involved 20 operative procedures. Four of the seven patients (57%) had a history of radiation to the affected mandible. Bony defects averaged 10.2 cm (range, 4.5 to 24 cm), and the associated soft tissue defects averaged 6 x 12 cm. Average follow-up was 16 months. Cosmetic (facial symmetry) and functional (speech quality, oral continence, deglutition, donor site morbidity, dental rehabilitation) results were evaluated by questionnaire and clinical examinations. RESULTS: Soft tissue coverage and mandibular restoration were successful in all patients, and flap survival was 100%. Five of the seven patients (70%) achieved good or excellent functional results, and five of seven (70%) achieved good or excellent esthetic results. Complications were minimal, and the average hospital stay was 14 days. CONCLUSIONS: When the initial attempt at mandibular reconstruction is unsuccessful, mandibular function and esthetics can be salvaged with reliable vascularized soft tissue and bone flaps. As long as appropriate flap options are considered and the patient is medically stable, successful mandibular reconstruction should be achievable despite the number or cause of prior failed attempts.
SPECIFIC AIM. To evaluate the take of skin grafts on conventionally prepared beds and on beds prepared by a carbon dioxide laser, with and without abrasion of the bed. SIGNIFICANCE. Graft take is dependent on hemostasis, immobility, and nutrition of the graft. Scalpel excision of the skin graft can be associated with hemostatic difficulties and laser treatment of the skin graft bed can provide hemostasis. Abrasion of the bed after laser treatment may then be a means of opening small lymphatic and blood vessels to maintain the graft. Laser treatment followed by abrasion of the bed may provide an ideal graft base before suturing of the skin graft. MATERIAL AND METHODS. Full-thickness skin grafts were taken with a scalpel at three sites on the dorsal skin of 24 guinea pigs. The three beds were prepared with pressure alone to provide hemostasis, laser vaporization followed by abrasion with gauze to produce pinpoint bleeding, and laser vaporization alone. The original skin from each of the sites was then sutured back in place. At postoperative days 1, 3, 5, 10, 21, and 35 the graft sites were assessed clinically for "take." Laser Doppler measurements were also made to evaluate blood flow. Histologic sections of the three sites were prepared. Immunohistochemical analysis was performed to evaluate cell proliferation and angiogenesis. RESULTS. For the animals sacrificed through day 10 the rate of take for the sites that were not lased was 100%. For the sites that were lased alone and lased and abraded the rate of take was 71% with no difference between the two techniques. The lased sites demonstrated increased inflammatory response and graft necrosis. Immunohistochemical analysis showed increased cellular proliferation and angiogenesis in the bed. DISCUSSION. Grafts take best on a scalpel-prepared bed. Laser preparation of the bed, with or without abrasion, demonstrates decreased "take." Therefore the carbon dioxide laser is not a recommended means to take a graft or prepare the graft bed.
Buccal mucosa is the preferred donor tissue for urethroplasty in many cases. This study documents donor site morbidity associated with this technique in 12 patients. Nine patients had a transiently decreased parotid salivary flow for 1 week, and one patient reported transient nerve involvement (long buccal nerve). Intraincisal opening returned to presurgical values within 6 weeks and in some cases exceeded presurgical values. This appears to be a low morbidity technique with high patient acceptance.
The purpose of this study was to determine the role of the fibular free flap in reconstructing lateral segmental defects of the mandible. Over the past 5 1/2 years, 17 consecutive patients underwent reconstruction of their lateral mandible with the fibular free flap. Patients included 12 men and 5 women, the mean age was 54 years (range, 29-76 years), and the mean length of the mandibular defect was 6.3 cm (range, 2.5-9 cm). The majority of patients with tumors (54%) were treated for recurrence and 92% received radiation to the operative field. The mean operative time to perform the microsurgery and bone plating was 4 hours. Postoperative morbidity occurred in 3 patients (18%) (plate fracture, malocclusion, orocutaneous fistula). Five patients (29%) required leg donor site skin grafting. Donor site morbidity included a minor cellulitis, a transient neuropraxia, and one case of leg swelling. None required additional surgery for donor complications. Thus far, 71% of the patients have received dental rehabilitation and 35% had osseointegrated implants placed in their bone flap. Eighty-two percent of the patients achieved both good or excellent aesthetic and functional results. Sixteen patients (94%) tolerate at least a soft diet and 65% are on a regular diet. Five patients developed tumor recurrence an average of 9 months postoperatively with a mean survival of 21 months. This study demonstrates that the fibular free flap is highly reliable for reconstructing the lateral mandible in a single stage, with low overall morbidity, and provides for excellent dental and speech rehabilitation. For most patients, the fibular free flap should be considered for lateral mandibular reconstruction even in those patients with a limited life expectancy.
Central giant cell granulomas (CGCGs) are jaw tumors of unknown origin that often exhibit an aggressive, though unpredictable, clinical course. The purpose of this study was to determine the immunoprofile of the mononuclear cells that seem to be responsible for the biologic behavior of these tumors. Numbers of cells in cell cycle were also determined and compared in clinically aggressive and non-aggressive CGCGs. Sixteen aggressive and 12 non-aggressive CGCGs were immunohistochemically stained with antibodies to CD34, CD68, factor XIIIa, alpha-smooth muscle actin, prolyl 4-hydroxylase, Ki-67, and p53 protein. Cell populations and numbers of cells in cell cycle were determined through microscopic quantitative assessment. CD34-positive cells were limited to support vessels. CD68-positive mononuclear cells constituted a small population of cells in all tumors. With two exceptions, factor XIIIa-positive cells were rarely seen. Alpha-smooth muscle actin staining was present in approximately half the tumors, and occasionally large numbers of positive cells were seen. Most mononuclear cells were positive for fibroblast-associated antigen. No phenotypic differences were detected between aggressive and non-aggressive tumors. P53 protein did not appear to be overexpressed in CGCGs. Ki-67 staining showed that only mononuclear cells were in cell cycle, and that there were no differences between aggressive and non-aggressive tumors. We conclude that CGCGs are primarily fibroblastic (and myofibroblastic) tumors in which macrophages appear to play a secondary role. Tumor cells show no differentiation toward endothelial cells or macrophage-related dendrocytes (factor XIIIa). Cellular phenotypes and numbers of cells in cell cycle are similar in both aggressive and non-aggressive tumors.
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Modern treatment of complex midfacial defects has evolved over the past 5 years, primarily with the advent of reliable vascularized bone flaps and osseointegrated implants. To determine the effectiveness of these advances, 26 consecutive patients with complex midfacial defects treated from 1991 through 1995 with immediate muscle-flap coverage were evaluated. The etiology of the defect included neoplasm (n = 23) and trauma (n = 3). Seventy-eight percent of the patients received adjuvant radiation therapy. Follow-up ranged from 3 months to 4 years, with a mean of 18 months. Twenty-three patients (88 percent) were reconstructed with a single major procedure. All patients had free-flap reconstruction, and 100 percent of the flaps survived. Late tumor recurrence was seen in 5 of 23 patients (22 percent) and was detected promptly. Aesthetic and functional results were rated good or excellent in 77 and 88 percent of the patients, respectively, as determined by patient questionnaires and physical examinations. Fourteen of 18 patients (78 percent) undergoing partial or complete alveolar ridge resection received dental rehabilitation, 43 percent of whom received osseointegrated implants into either a bone flap or remaining native bone. Osseointegrated implants were inset during the initial reconstruction 50 percent of the time. A treatment algorithm for free-flap selection based on the size of the defect and the bony requirement for reconstruction is presented. Bony restoration is only required in those areas where osseointegrated implants need to be placed. In such cases, the fibula osteocutaneous free flap is the flap of choice. Otherwise, soft-tissue flaps are selected based on wound size. Immediate free-flap coverage provides effective, single-stage treatment, both aesthetically and functionally, for complex midfacial defects.
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OBJECTIVE: To establish a treatment algorithm for reconstructing complex midfacial defects. DESIGN: Retrospective case series. SETTING: University-based teaching hospital. PATIENTS: Thirty-one consecutive patients were treated from 1991 through 1995. The 18 males and 13 females were aged 15 to 90 years (mean age, 58 years). The cause of the defect included neoplasm (n = 27) and trauma (n = 4). Reconstruction consisted of 1 of 4 free flaps: rectus abdominis, radial forearm, fibula, or latissimus dorsi. Aesthetic and functional results were determined by patient questionnaires and physical examinations. MAIN OUTCOME MEASURES: Length of stay, postoperative morbidity and mortality, degree of aesthetic and functional restoration, and detection of tumor recurrence. RESULTS: Twenty-seven (87%) of the 31 patients underwent reconstruction with a single major procedure. All of the flaps survived. Postoperative hospital stays averaged 14 days. Late tumor recurrence occurred in 7 (23%) of the 31 patients and was promptly detected. Aesthetic and functional results were rated good or excellent in 77% (24/31) and 87% (27/31) of patients, respectively. Of the 20 patients who underwent alveolar ridge resection, 16 (80%) received dental rehabilitation, 44% of whom received osseointegrated implants into either a bone flap or remaining native bone. Osseointegrated implants were inset during the initial reconstruction 57% (4/7 patients) of the time. CONCLUSIONS: For complex midfacial defects, free-flap transfer can be performed with a high degree of success, restoring both appearance and function in most patients. The only instance in which bone is necessary to reconstruct the midface involves those areas in which osseointegrated implants are needed, ie, alveolar ridge (dental implant) and/or orbit (ocular prosthesis). In such cases, the fibula osteocutaneous free flap is the flap of choice. Otherwise, soft-tissue flaps are selected based on wound size.
Hyaluronan (hyaluronic acid) is a glycosaminoglycan that functions as a constituent of ground substance, a mediator of cell proliferation and would healing, and that plays a prominent part in tumorigenesis as well as in embryogenesis. Its presence and possible role in saliva has been subjected to little study. Unstimulated and stimulated pure parotid and mixed saliva was obtained from 10 volunteers. The protein content of the samples was assayed and the hyaluronan concentration was evaluated by means of an enzyme immunosorbent-like assay using a hyaluronan-binding peptide. Stimulated whole saliva had the highest protein content (mean 1.26 mg/ml) followed by unstimulated parotid saliva (1.15 mg/ml), stimulated parotid saliva (0.95 mg/ml) and unstimulated whole saliva (0.93 mg/ml). Absolute hyaluronan concentrations were highest in unstimulated whole saliva (mean 459.2 ng (nanograms)/ml), and lowest in stimulated parotid saliva (82.7 ng/ml). When hyaluronan concentrations are expressed as ng/mg of protein, the highest are in the unstimulated whole saliva (mean 477.5 ng/mg protein) followed by stimulated parotid saliva (229.7 ng/mg), unstimulated parotid saliva (179.6 ng/mg) and stimulated whole saliva (159.9 ng/mg). There are wide variations in the levels of hyaluronan in human saliva depending on the type of saliva and the conditions at the time of collection. Regulation of hyaluronan metabolism represents an intricate balance between production and degradation, and it is unclear whether elevated concentrations of hyaluronan in response to tissue proliferation, regeneration or repair. The hyaluronan may contribute to the healing properties of saliva, assisting in protecting the oral mucosa and adding to the lubricating properties of saliva.
PURPOSE: This study evaluates magnetoencephalography (MEG) as an objective monitor for the evaluation of post-traumatic inferior alveolar nerve injuries. MATERIALS AND METHODS: Six patients with unilateral inferior alveolar nerve injuries were assessed using conventional sensory examination techniques. All damaged nerves, and their contralateral controls, were then reexamined using MEG technology. Regions of somatosensory-induced magnetic activity were superimposed on three-dimensional magnetic resonance imaging (MRI) scans to give cortical magnetic source images (MSI). All patients subsequently underwent surgical exploration of the damaged nerves. RESULTS: All six patients had no sensitivity to conventional testing on the damaged side. On evaluation with MEG, all six control nerves had an appropriate cortical signal in response to repetitive lip stimulation. Somatosensory stimulation of two of the six damaged nerves resulted in cortical magnetic field changes. Surgical exploration showed that the four nerves with negative MEG tests had discontinuity defects. In contrast, the two patients with positive MEG signals had intact nerves. CONCLUSION: This technology may differentiate between intact but damaged nerves and transected nerves.
PURPOSE: This cadaver dissection studied the relationship of the buccal branch of the facial nerve to the parotid duct and its relevance to surgical procedures in this area. MATERIALS AND METHODS: Ten cadaveric heads (twenty sides) were dissected. The superficial tissues were removed, and the buccal branch of the facial nerve and the parotid duct were identified. The vertical and horizontal relationships were recorded and analyzed. RESULTS: Eighty-five percent of the cadavers had a single buccal branch of the facial nerve, whereas 15% had two branches. In 75% of cases, the nerve was inferior to the duct as it emerged from the parotid gland, whereas in 25% of cases the nerve crossed the duct, usually from superior to inferior. CONCLUSION: The buccal branch of the facial nerve has a close relationship with the parotid gland for over 2.5 cm after it emerges from the parotid gland; it normally lies inferior to the duct. This relationship is of importance in performing parotid gland surgery, parotid duct surgery, and some facial cosmetic surgery.
From a systematic study of 500 references randomly selected in the January through July, 1992, issues of the Journal of Oral and Maxillofacial Surgery, it was found that 26% had errors. 6.2% of the referenced articles could not be found at all; either due to the fact that they were obscure foreign articles, their age made it difficult to verify, they cited non-peer reviewed journals, or the references cited journals that possibly did not exist. The remaining references were verified either from the original source or from other indexing tools if the original was not available.