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Biomedical subjects

W H Bell

Publications and source records attributed to W H Bell.

At least 73 records · Page 4Linked to original sources
PubMed1991

Condyle position and mobility before and after intraoral vertical ramus osteotomies and neuromuscular rehabilitation.

Correction of dentofacial deformities in patients with existing temporomandibular dysfunction and pain by intraoral vertical ramus osteotomies may result in improved function and resolution of symptoms. A prospective study of condylar position and mobility was made in nine patients with anterior disk displacements with reduction and associated temporomandibular pain and dysfunction. Each patient was treated by bilateral intraoral vertical ramus osteotomies with 2 to 3 weeks of maxillomandibular fixation and no interosseous fixation of the proximal segment. Condylar position and mobility in the surgical group were compared with normative values derived from seven individuals without discernible pain or dysfunction. Immediately postoperatively, the condyle was consistently positioned anteriorly and inferiorly, but the condyles tended to return to their preoperative position. Condylar mobility after surgery exceeded presurgical mobility and was associated with improved mandibular function.

Centric Relation↗
PubMed1990

Safe extracranial vascular evaluation and surgery without preoperative arteriography.

Carotid surgery without preoperative arteriography was performed in 101 consecutive patients with an average age of 68.5 years and almost equal sex distribution. This prospective study analyzed risk factors, operative approach, bruits, indications for surgery, and outcome. All patients were studied by real-time B-mode ultrasound and spectral analysis and none were referred for arteriogram. The majority of patients had a standard carotid endarterectomy, and the findings at surgery correlated with noninvasive imaging. No mortality was recorded in this series of patients; a 1% rate of neurologic morbidity was noted. These results suggest that one can safely operate on the basis of a duplex scan. A preoperative arteriogram is not always necessary for carotid evaluation.

Aged↗
PubMed1990

Increased prostacyclin and thromboxane A2 formation in human varicose veins.

Increased urinary metabolites of the antiaggregatory vasodilator prostacyclin (PGI2) and the proaggregatory vasoconstrictor thromboxane A2 (TXA2) have been reported in deep vein thrombosis; however, the tissue(s) of origin is uncertain. Because little is known about the formation of PGI2 or TXA2 from its common precursor, prostaglandin (PG) endoperoxide H2 (PGH2), by varicose veins, we determined the formation of 6-keto-PGF1 alpha (the stable metabolite of PGI2), TXB2 (the stable metabolite of TXA2), and PGE2. Segments of normal saphenous vein and varicose vein (nine and six patients, respectively) were incubated with 10 microM [14C]PGH2 for 2 min at 37 degrees C; products were separated by thin-layer chromatography. Surface area and mass of normal and varicose vascular segments were 19.5 +/- 0.8 versus 18.8 +/- 0.6 mm2 and 11.6 +/- 1.4 versus 10.7 +/- 0.7 mg, respectively. Formation of 6-keto-PGF1 alpha and TXB2 by the segments of varicose vein was significantly increased over that of normal vein: 157 +/- 14 versus 243 +/- 17 pmole of 6-keto-PGF1 alpha (P less than 0.005) and 22 +/- 3 versus 35 +/- 5 pmole of TXB2 (P less than 0.01). The formation of PGE2 by segments of varicose vein was not significantly different from that of normal vein (201 +/- 9 vs 219 +/- 11, respectively). Deoxyribonucleic acid (DNA) content of normal and varicose vein was 1.69 +/- 0.12 and 1.51 +/- 0.13 mg per gram of tissue, respectively. The data suggest that the increased PGI2 formation may reflect increased activity or content of PGI2 synthase. The increase in TXA2 formation may reflect increased productivity or an increased presence of residual platelets or microemboli.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

Normal angiograms and carotid pathology.

Nonstenotic ulcerated atherosclerotic plaques of the carotid arteries may be associated with symptoms of transient ischemic attacks, amaurosis fugax, and stroke. Preoperative evaluation of patients with these symptoms has traditionally included ultrasound and arch aortography angiograms of the area of the carotid bifurcation. Recent evidence has shown that ultrasound is more accurate in detection and morphologic delineation of these nonstenotic lesions. We analyzed the hospital records of 21 patients with ultrasonographic evidence of disease in whom arteriograms were negative. The patient group comprised 15 men and six women, with an average of 66 years. All patients had symptoms of hemispheric transient ischemic attacks and were evaluated with B-mode ultrasound and arteriography. Ultrasound was positive and arteriogram "negative" in all of the patients (i.e., described by the radiologist as without hemodynamic significant disease or ulceration, or as normal). The ultrasound diagnosis was confirmed at operation with findings of 20 to 50 per cent stenosis and ulcerative plaques. At retrospective review of the arteriograms, three ulcerations were found in the 21 patients. We conclude that B-mode ultrasound better defines nonstenotic ulcerative lesions and decisions to perform carotid endarterectomy may be based on either positive test. An ulcerative plaque by B-mode ultrasound and appropriate symptoms, therefore, may not require angiography before operation.

Aged↗
PubMed1990

Treatment of temporomandibular joint dysfunction by intraoral vertical ramus osteotomy.

The purpose of this study was to determine if the intraoral vertical ramus osteotomy is an effective treatment for anterior disk displacements with reduction and associated temporomandibular joint pain and dysfunction. Success with this procedure was predicated on producing a more functional articular disk-condyle relationship by anterior and inferior repositioning of the condyle. The prospective study was undertaken of nine (eight female and one male) patients (mean age of 25.8 years) with anterior disk displacement with reduction and associated temporomandibular joint pain and dysfunction (mean duration of pain of 6.8 years). History, clinical dysfunction, and pain indices were used to determine the frequency and severity of temporomandibular joint dysfunction. The incidence of ear pain, muscle fatigue, tinnitus, headaches, and clicking was also assessed. The severity of the pain experience in the masticatory muscles and temporomandibular joints was evaluated through the use of a pain index. The severity of the pain experience and temporomandibular joint dysfunction in all of the patients was significantly reduced or totally eliminated during the period of followup. Surgical treatment of anterior disk displacement with reduction by intraoral vertical ramus osteotomy resulted in improved temporomandibular joint function and resolution of symptoms.

Adolescent↗
PubMed1989

Masseter muscle adaptation following surgical correction of vertical maxillary excess.

This study was designed to examine the adaptive response of the human masseter muscle following surgical correction of abnormal facial form. Biopsies of the deep surface of the anterior superficial masseter muscle were obtained from five patients demonstrating vertical maxillary excess (VME), one at the time of corrective surgery, and a second at a long-term postoperative time interval (mean, 8 months). Control biopsies were also obtained from five individuals (three cadavers and two patients) with normal dentofacial morphology. A standard regimen of histologic and histochemical staining was used to classify individual muscle fibers as either type 1, type 2, or intermediate. In both VME patients and normal subjects type 1 fibers predominated, with the control group displaying a higher percentage (50% vs. 43%). On the average, type 1 fibers also had the largest areas. Following surgery there was an increase in type 2 fibers (30% vs. 52%). Two patients receiving maxillary surgery only exhibited either no change in mean fiber area or only a slight increase. The three remaining patients who underwent concomitant maxillary and mandibular surgery all showed a significant decrease in mean fiber area. Two persons in the latter group also showed features consistent with a denervation-reinnervation process. The results of this study indicate that the human masseter responds to surgical manipulation of the jaws in a histochemically demonstrable manner, with the nature and magnitude of the response associated with the particular surgical procedure(s) performed.

Adaptation, Physiological↗
PubMed1989

Cost effectiveness of regional anesthesia in carotid endarterectomy.

The purpose of this prospective study was to assess safety, efficacy, and hospital costs (excluding medications) and laboratory tests related to general (GA) and regional anesthesia (RA) for carotid endarterectomy (CEA). One hundred patients underwent CEA; 50 received GA and 50 received RA. Thirty-eight men (eight diabetic) and 12 women (two diabetic), with an average age of 62.4 (47 to 79) years comprised the GA group; 35 men (six diabetic) and 15 women (one diabetic), with an average age of 64.1 (51 to 74) years comprised the RA group. Twenty-one patients (17 men, 4 women) in the GA and 24 patients (19 men, 5 women) in the RA group had hypertension. Every patient had some stigmata of cardiac disease. Patients receiving GA for CEA spent an average of 1.2 days in the surgical Intensive Care Unit (ICU) and 6.1 days in a regular hospital bed, for an average cost of $4547. The patients who underwent CEA under RA had an average of 0.1 ICU days and 4.1 regular hospital days, for a cost of $2067. RA saved $2480 per patient and $124,000 in our study group, with no increase in mortality or morbidity rates (P less than 0.001). RA is superior to GA in cost-effectiveness for patients undergoing CEA.

Anesthesia, Conduction↗
PubMed1989

Amaurosis fugax: carotid endarterectomy without an angiogram.

The risks of carotid angiography--technical, allergic, cardiac, renal, or emotional--may be lessened or absented by the use of real-time B-mode ultrasound to evaluate carotid artery disease. A patient with amaurosis fugax, a positive fluorescein angiogram, ulceration on ultrasound, and an unremarkable computed tomography scan was operated on without angiography. The pathology was correct and the patient did well.

Aged↗
PubMed1988

Relationship of mandibular anterior tooth apices to genial muscle attachments.

Ten adult midsagittally sectioned cadaver heads were used to measure the distance between the apex of the central incisor or canine teeth and the attachment of the genioglossus or geniohyoid muscles. Measurements were made on both cadaver specimens and radiographs. The results of the two methods showed no statistically significant difference. The results indicate that there is a relatively small chance (5.6%) of including the genioglossus attachment in the lingual pedicle if an anterior mandibular subapical osteotomy is positioned 3 to 5 mm below the incisor apex but a large chance (65%) of including the genioglossus muscle when the osteotomy procedure includes the canine teeth.

Adult↗
PubMed1988

Long-term evaluation of human teeth after Le Fort I osteotomy: a histologic and developmental study.

Transient pulpal vascular ischemia and direct injury to the apices of the teeth have been implicated as the causes of degenerative and atrophic pulpal changes in experimental animals after Le Fort I osteotomy despite the presence of collateral circulation. The long-term clinical effect of these pathologic changes in human teeth has not been studied. Seventeen maxillary third molar teeth from 10 patients whose postsurgical follow-up ranged from 6 months to 78 months (mean, 40 months) were extracted. The long-term biologic effects of Le Fort I osteotomy on the pulp and on the development of teeth were retrospectively evaluated with clinical and standard histologic techniques. Normal teeth from patients who were not operated on were used as controls. Histologic examination revealed an intact pulpal circulation and minimal pathologic changes in the pulpal tissue. Clinical and radiographic studies showed that the growing teeth developed normally after surgery. The Le Fort I downfracture procedure had little discernible long-term effect on the pulp and on the development of human third molar teeth.

Adolescent↗
PubMed1988

Microangiographic and histologic evaluation of revascularization and healing after genioplasty by osteotomy of the inferior border of the mandible.

Correlated microangiographic and histologic studies in adult rhesus monkeys indicate that a pedicled genioplasty involving osteotomy of the inferior mandibular border maintains circulation and osseous viability of the repositioned genial segment. Circulation to the dental pulps was also not discernibly affected when accomplished a minimum of 8 mm below the root apices.

Angiography↗
PubMed1988

Does intracranial dye study contribute to evaluation of carotid artery disease?

One thousand consecutive cerebral arteriograms for suspected carotid artery disease were retrospectively evaluated for the intracranial disease component. Only 784 patients (78 percent) had arteriograms of the intracranial circulation. Forty-six patients (6 percent) had siphon stenosis in the range of 5 to 70 percent. No patient had a lesion encompassing more than 75 percent of the vessel diameter. Thirteen patients (2 percent) had intracranial aneurysms. All patients were asymptomatic from the standpoint of their aneurysms and none required surgical intervention. One additional patient was noted to have an intracranial tumor, which was confirmed by computerized tomography. In this patient population, intracranial dye study did not provide information that altered management.

Adult↗
PubMed1986

Simultaneous repositioning of the maxilla, mandible, and chin. Treatment planning and analysis of soft tissues.

There is a clinical, biologic, and biomechanical foundation for simultaneous surgical repositioning of the maxilla, mandible, and chin in a significant proportion of adult and adolescent patients. The restoration of normal jaw function, optimal facial esthetics, and long-term stability are the sine qua non of successful orthognathic surgical procedures to simultaneously reposition the jaws. The key to the achievement of these objectives is to carefully and systematically analyze facial esthetics, establish esthetic priorities, and then coordinate and implement them through the use of cephalometric planning and occlusal studies. By meticulous and precise surgical technique, properly programmed, coordinated, and sequenced with efficient presurgical and postsurgical edgewise orthodontic therapy, and systematic postsurgical neuromuscular rehabilitation, the maxilla, mandible, and chin can be simultaneously repositioned with relatively few postoperative complications or sequelae. This article purposes to elucidate on the indications for two-jaw surgery and describe a simplified clinical-cephalometric analysis for orthognathic surgery. Representative case reports are presented and discussed to illustrate the esthetic, orthodontic, and surgical treatment objectives. The basic problems involved in diagnosis and treatment planning of patients who require two-jaw surgery are discussed as well.

Adolescent↗