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.

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.

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.

Effect of electrical stimulation on mandibular distraction osteogenesis.

This study was designed to examine whether the use of electrical stimulation during mandibular lengthening accelerates new bone formation. Twenty adult female rabbits weighing between 2800 g and 3200 g underwent left mandibular body osteotomy. After a 3 day latency period, an external fixation device was activated at a rate of 0.7 mm per day for 10 days. Direct current electrical stimulation of 10 microA was applied to 10 rabbit mandibles. Two of the screws were used as electrodes during the distraction phase. The other 10 rabbits (control group) were not stimulated. The device was then stabilized for periods of 10, 20, 30 and 60 days in both groups. The distraction segment was evaluated radiographically by assessing the proportion of bone mineral density using a dichroma scan. The amount of new bone formation was studied histologically with an image analyzer to evaluate the bone formation in the distraction gap. Histological examination showed that the new bone formation 10 and 20 days after distraction was greater in the electrical stimulation group than in the control group. Ten and 20 days after distraction, image analysis and analysis of bone mineral density in areas of newly formed bone indicated that there was a greater amount of new bone formation in the stimulation group than in the control group. The radiographic evaluation, however, did not demonstrate significantly different images between the stimulation group and the control group. Thirty and 60 days after distraction, no difference in the amount of new bone formation was noted in either the experimental or the control groups. These results indicate that electrical stimulation during gradual distraction promotes new bone formation in the early retention period in a rabbit model.

Long-term osseous and soft tissue changes after large chin advancements.

When a large chin advancement is performed and a broad musculo-periosteal pedicle is preserved, excessive stretching of the suprahyoid musculature may occur, leading to instability or resorption of the advanced genial segment. The present study was designed to evaluate long-term osseous and soft tissue changes after large advancement genioplasties (greater than 10 mm), achieved by horizontal osteotomy of the inferior border of the mandible, with preservation of a musculo-periosteal pedicle to the advanced genial segment. Bone remodeling and the inherent soft tissue changes were radiographically assessed in a long-term follow-up period (mean = 26.8 months), with attention to observe progressive osseous changes. Despite the observed 17% bone resorption, the enveloping soft tissues of the chin followed the bony movement in a ratio of 1:0.83. Osseous resorption was not progressive, and the soft tissue changes remained unaltered. A broad musculo-periosteal pedicle consistent with the surgical objective should remain attached to the advanced genial segment to minimize osseous resorption and achieve more predictable soft tissue changes. We emphasize the need for a longer follow-up period (25-30 years) to determine the effect of the stabilization devices and osseous remodeling, specially in younger patients.

Mandibular widening by intraoral distraction osteogenesis.

Transverse mandibular deficiency with crowding of the mandibular anterior teeth is frequently present in patients with Class I and II malocclusions. The hallmarks of treatment by compensating orthodontics, functional appliances or orthopaedic devices are instability, compromised periodontium and compromised facial aesthetics. A new surgical technique has been developed to widen the mandible. The method is based upon gradual osteodistraction following vertical interdental symphyseal osteotomy. Ten patients with transverse mandibular deficiency and significant dental crowding were treated by symphyseal distraction and subsequent non-extraction decompensating orthodontic treatment. Either an intraoral tooth-borne Hyrax appliance or a new custom-made bone-borne osteodistractor was used to gradually widen the mandible. The surgical procedures were accomplished under local anaesthesia and intravenous sedation in an ambulatory surgical setting using an individualized distraction protocol. The appliances were activated 7 days after symphyseal osteotomies, once each day at a rate of 1 mm per day and stabilized for 30-40 days after distraction. After the segments were distracted, non-extraction orthodontic alignment of the mandibular anterior teeth was accomplished. The symphyseal distraction gaps were bridged by new bony regenerate. Distraction osteogenesis provided an efficient surgical alternative to orthognathic surgery for widening the mandible and treatment of transverse mandibular deficiency without extraction of teeth.

Distraction osteogenesis to widen the mandible.

The purpose of this investigation was to elucidate the biology of distraction osteogenesis during mandibular widening. Midsymphyseal vertical interdental osteotomies were performed in nine Macaca mulatta monkeys. After a latency period a tooth-borne appliance was activated at a rate of 0.5 mm twice a day for 7-10 days. The appliance was then stabilized for a period of 4 or 8 weeks. The distraction gap at the inferior portion of the symphysis was bridged completely by new bony trabeculae. Bone formation in the interdental area was apparently related to the surgical technique. Newly formed bony trabeculae were oriented parallel to the direction of distraction. The location of the osteotomy site with an adequate margin of alveolar bone contiguous with the adjacent teeth was necessary for the induction of the distraction osteogenesis. Disproportional movement between superior and inferior portions of the distracted segments was noted.

Positional changes and stability of bone segments during simultaneous bilateral mandibular lengthening and widening by distraction.

The purpose of this study was to analyse the skeletal changes and stability of the distracted segments during and after simultaneous widening and bilateral lengthening of the mandible in baboons with a miniaturized intraoral bone-borne osteodistractor. Distraction appliances were activated 5 days after vertical posterior body and midsymphyseal osteotomies at a rate of 0.9 mm/day for 10 days. The appliances were then stabilized for a period of 8 weeks, after which the animals were killed. The distraction gaps and gingival tissues were studied clinically and on standardized radiographs. The proportional movement of the distracted segments that we found supports the clinical use of the miniaturized intraoral bone-borne distraction appliance to widen and lengthen the mandible selectively. It also supports the concept of positioning the mandibular osteodistractors parallel to the common vector of distraction, which should parallel the corrected maxillary occlusal plane.

Reactive changes in the temporomandibular joint after mandibular midline osteodistraction.

The purpose of this study was to evaluate the histologic changes within the condyle in response to mandibular widening using osteodistraction. Mandibular midline osteotomies were made in nine Macaca mulatta monkeys and tooth-borne distraction devices were bonded to the mandibular dentition. Distraction was continued until a 3-5 mm widening was achieved. The appliances were then stabilized for a period of 4 weeks. Non-decalcified sagittal sections of the lateral, middle and medial thirds of the condyles were analyzed. Although three of the seven animals showed no unusual morphology, four others exhibited morphologic differences within the fibrous layer, cartilage layer or bone/cartilage interface. Histologic changes were seen to occur in the fibrous layer, cartilaginous layer and cartilage/bone interface. The severity of these changes were correlated with the likely rotational forces directed at the condyle on the postero-lateral and antero-medial surfaces.

Soft-hard tissue correlations and computer drawings for the frontal view.

Hard and soft tissue measurements were obtained for nine Caucasian women. Based on these measurements, regression formulas were derived to approximate the soft tissue covering based on hard tissue data. The results are presented iconically by computer drawings. The preliminary data presented would suggest a definite predictable influence exerted by the facial skeleton on the position of landmarks in the overlying soft tissue.

Temporomandibular joint adaptation following inferior repositioning of the maxilla in adult monkeys.

Treatment of adults with vertical maxillary deficiency (short faces) has continually been an intriguing challenge for surgeons and orthodontists. For this category of patients, the introduction of simultaneous bone grafting and Le Fort I osteotomy has opened the door for improved treatment. However, despite the improved surgical techniques, surgeons have been reluctant to increase the vertical dimension of the maxilla by Le Fort I osteotomy with interpositional bone grafts because of inconsistent and variable stability after surgery. This study examines structural and functional adaptation of the adult temporomandibular joint and stability in a primate model following surgical lengthening of the maxilla in the vertical dimension. Results suggest that maxillary surgery and autorotation can alter condylar stress within physiologic ranges. However, further studies are indicated to clarify the surgery's long-term effect.

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.

Intraoral mandibular distraction osteogenesis.

During recent years, distraction osteogenesis has gained in popularity for the treatment of various bone deficiencies either in the vertical, transverse, or anteroposterior dimension. Distraction osteogenesis has been shown to be an effective technique for mandibular widening and lengthening where traditional orthognathic surgery has important limitations. The intraoral approach to these procedures prevents damage to the inferior alveolar nerve and the developing dental follicles, and eliminates hypertrophic facial scars. Intraoral distraction osteogenesis also avoids donor-site morbidity, and minimizes the need for blood transfusion or prolonged fixation. This intraoral application provides for enhanced patient acceptance and reduces the potentially negative psychosocial effects of wearing an extraoral distraction appliance.