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Biomedical subjects

H B Williams

Publications and source records attributed to H B Williams.

At least 19 recordsLinked to original sources
PubMed1995

Alveolar cleft bone grafts: results and imprecisions of the dental radiograph.

Alveolar cleft bone grafts customarily have been evaluated by one-dimensional dental radiographic measurements. Based on the dental radiograph, remarkable successes with just a single bone graft have been reported in the literature. At the Montreal Children's Hospital, the experience with 101 alveolar bone grafts in 62 cleft lip and palate patients was retrospectively reviewed to determine (1) the precision of dental radiographs at evaluating the clinical outcome, (2) the effect of dental maturation on alveolar bone grafts, and (3) the effect of augmentation bone grafts. The dental radiograph significantly overestimated the number of clefts that could be managed orthodontically (p < 0.01, McNemar's test) and thus poorly prognosticated the ability to achieve bony obliteration of the alveolar cleft and orthodontic closure of the dental gap. Bone grafts performed during the preeruptive canine dentition yielded significantly better results (p < 0.05, chi-squared test). With each subsequent augmentation bone-graft procedure performed, there existed a trend toward improved dental arch stability and radiographic and clinical outcomes.

Adolescent↗
PubMed1989

The importance of venous drainage in rat flaps: an experimental study.

Venous drainage of musculocutaneous grafts prepared on the backs of rats survived successfully by preserving the draining vein. Even in musculocutaneous flaps, venous drainage at the distal part of the flap plays an important role in a successful take. An experiment was prepared in a rat model in which the iliolumbar veins were utilized as the draining veins, and musculocutaneous flaps, 4 x 10 cm in size, were created. In this experiment, it was shown that even in random pattern musculocutaneous flaps, necrosis can be prevented by preserving the draining vein.

Angiography↗
PubMed1988

The effects of electrical stimulation on denervated muscle using implantable electrodes.

This experimental study investigated the effects of continuous electrical stimulation on denervated muscle. The canine peroneal nerve was severed and repaired microsurgically, and the denervated extensor muscle group of the leg was stimulated continuously with an implantable electrode and pulse generator. EMG study, muscle force measurement, muscle weight measurement, histology, and histochemistry were performed to study the effect at eight weeks after the operation. Continuous electrical stimulation (pulse frequency 130 pps, burst rate approximately 1 train/min) was effective in decreasing muscle atrophy and in improving muscle force. These findings may have broader clinical applications.

Animals↗
PubMed1986

The importance of internal anatomy of the peripheral nerves to nerve repair in the forearm and hand.

We have completed and analyzed recent studies on the internal topography of the median and ulnar nerves of the forearm and hand. These findings have been compared with the classic studies of Sir Sydney Sunderland and more recent work by other authors has been included. Our studies confirm that there is a complex interfascicular relationship between the various components of the median and ulnar nerves in the forearm and hand, but, with careful dissection, several anatomic relationships can be defined. Individual branches and bundles can be traced within the main nerve trunks for considerable distances without significant trauma to the conducting fibers. These include the recurrent branch of the median nerve, the branches to the lumbrical muscles, the motor and sensory components of the ulnar nerve, and the dorsal sensory branch of the ulnar nerve. These findings have a direct relationship to the clinical repair of fresh nerve injuries as well as those injuries that require nerve grafting for significant gaps in the neural tissue. Intraneural neurolysis can be safely performed if detailed knowledge of the internal topography of the peripheral nerves is understood. This knowledge may also be applied to the dissection and management of neuromas in continuity. The increased awareness of the interfascicular relationships of the peripheral nerves may well influence a more favorable outlook in the care of patients with nerve injuries.

Dissection↗
PubMed1984

Circulation, bone scans, and tetracycline labeling in microvascularized and vascular bundle implanted rib grafts.

The circulation in microvascularized rib grafts has been compared with that in conventional rib grafts and in those augmented by a direct vascular bundle implantation into the bone grafts. A new experimental model has been designed to correlate vascular perfusion, bone scan patterns, tetracycline labeling, and histological findings in these bone grafts. Posterior microvascularized rib grafts were found to have a circulatory pattern identical to that of the normal rib. Failed microvascularized rib grafts were revascularized more slowly than conventional rib grafts. Vascular bundles implanted into rib grafts remained patent and increased the rate of revascularization. The stripping or preservation of periosteum had no observable effects on the rate or pattern of conventional rib graft revascularization. The circulation in rib grafts was accurately reflected in technetium 99 bone scans, as was the patency of the anastomoses of microvascularized rib grafts and of implanted vascular bundles. In contrast, tetracycline labeling was repeatedly observed in avascular areas of bone grafts and, therefore, is not a reliable indicator of bone graft circulation.

Animals↗
PubMed1984

The vascular pattern and viability of microvascularized rib grafts based on periosteal circulation--an experimental study.

Previous reports have stressed the importance of the nutrient blood supply in rib grafts transferred by microvascular anastomoses. In the present experimental study, we have demonstrated that a rib graft transferred by microvascular anastomoses based on periosteal vessels can survive; vascular clearing studies demonstrated that the vascularity of these grafts extends not only into the cortex but the medulla as well. The relative facility of harvesting these grafts (compared with those based on nutrient vessels) should make them the favored choice. Technetium bone scintigraphy proved accurate in the assessment of both vascular pattern and microanastomotic patency. Tetracycline labeling did not correlate well with the patency of a rib graft's pedicle blood supply.

Animals↗
PubMed1984

Are burn wound biopsies obsolete? A comparative study of bacterial quantitation in burn patients using the absorbent disc and biopsy techniques.

A study of bacterial quantitation in burn wounds was undertaken to compare a new absorbent paper disc technique with the standard burn wound biopsy technique. In the first part of the study 228 paired samples were used to compare the two methods; a high correlation coefficient was found with the four most commonly encountered bacteria, and both methods showed a high specificity and sensitivity for each of the organisms. In the second portion of the study, the discs were compared with burn wound biopsies that had been divided into their superficial and deep segments. Thirty paired samples were studied and again the correlation was high, indicating that the disc technique also measured the organisms found in the deeper tissue levels. The absorbent disc technique is simple, convenient, noninvasive, inexpensive, and yields reproducible results. These findings indicate that burn wound biopsies may no longer be required for infection monitoring in the burn patient.

Bacterial Infections↗
PubMed1984

Early enteral feeding of patients with major burns: prevention of catabolism.

The immediate onset of hypermetabolism after a major burn dictates that nitrogen and calories be supplied as early as possible to such patients to prevent the well-documented catabolic state. However, intravenous hyperalimentation is not always possible, and enteral feeding is not usually attempted in the early resuscitative period. Twelve patients with major burns (40% to 70%) were fed nasoduodenally in the early postburn period with a new solution (3.5% Aminosyn, 25% Polycose, and appropriate additions of electrolytes and vitamins). All patients reached positive nitrogen balance in 9.8 +/- 2.3 days, tolerated the feeding extremely well, and had no distention or diarrhea. Metabolic assessment showed remarkable stability. The characteristic signs of hypermetabolism, such as hyperglycemia and hypoinsulinemia or hyperinsulinemia, were absent. Furthermore, there was no persistent neutrophilia or leukocytosis and there was a significant (p less than .01) decrease in the percentage of juvenile neutrophils and a significant (p less than 0.001) increase in absolute lymphocytes between days 0 and 14 of the study. These data indicate that early enteral feeding of Polycose-Aminosyn is safe and well tolerated, and that the small intestine absorbs nutrients readily in the early postburn period, leading to positive nitrogen balance, preventing loss of serum protein, assisting in the maintenance of normal carbohydrate metabolism, and restoring granulocytes and lymphocytes to normal ratios.

Blood Cell Count↗
PubMed1984

Epignathus: a report of two cases.

Two cases of epignathus are presented. The classification and clinical and radiological diagnoses are reviewed. Epignathi are rare embryological tumors, but with better preoperative assessment and awareness, safe surgical excision can be carried out. A careful long-term follow-up with regular examinations is essential to detect any residual lesions or extensions of the original embryological malformation.

Angiography↗
PubMed1984

The painful stump neuroma and its treatment.

Successful clinical management of symptomatic neuromas continues to present a challenge to the responsible surgeon. It is unexplained why some patients with neuromas are completely asymptomatic while others exhibit debilitating symptoms. Prevention of neuromas is paramount with precise attention to severed nerves following amputations and other surgical procedures. Once established, treatment of neuromas consists of careful patient counseling, local massage, and desensitization procedures. Sympathetic blockade with guanethidine may be beneficial in some patients. When necessary, surgical excision of the neuroma along with a combination of funiculectomy, epineurial sleeve suture ligation, and silicone capping offers the best chance for eradication. In intractable or recurrent cases and following careful patient selection, neuroma excision followed by nerve grafting combined with sympathetic blockade using guanethidine can be successful in a significant number of cases.

Autonomic Nerve Block↗
PubMed1983

Use of myocutaneous flaps to repair defects in cases of multiple trauma.

The successful closure of soft tissue and bony defects caused by multiple trauma continues to present a formidable challenge to surgeons. The advent of myocutaneous flaps and their broadening use has given a new dimension to the clinical management of these patients. The excellent blood supply of these anatomically designed flaps allows for their transposition and coverage even of large defects. Increasing use of these flaps will undoubtedly lead to more rapid healing, fewer infections and a subsequent reduction in morbidity for patients with these complex problems of the trunk and extremities.

Adolescent↗
PubMed1982

Staged repair of ectopia cordis.

Ectopia cordis is a challenging congenital anomaly that generally has defied repair because of the magnitude of the deformity and the associated defects, particularly the intracardiac anomalies. We were fortunate to be presented with a boy who had successfully undergone an operation on the day of his birth to provide skin coverage over his bare ectopic heart. Subsequent studies disclosed no intracardiac anomalies. This paper describes the second stage of his repair designed to place the heart within the thorax and construct a bony shield anterior to it.

Follow-Up Studies↗
PubMed1980

Vascular neoplasms.

Vascular neoplasms in the broad sense represent a very common group of tumors or hamartomas that show great variability in gross appearance, microscopic appearance, and clinical course. Generally, neoplasms are composed of one cell type, but vascular neoplasms are collections of endothelial-lined tubes or tubules with connective tissue walls that may contain smooth muscle cells, pericytes, and nerve elements according to the specific tissues of origin. The classification of vascular neoplasms as outlined in this article attempts to delineate each tumor or hamartoma according to its histologic appearance and clinical behavior. The clinical course ranges from completely benign, self-involuting malformations such as the strawberry hemangioma to highly malignant angiosarcomas with their rapid growth and frequent metastases. Defects in the lymphatic system show gradations from simple lymphangiomas through lymphedema and lymphangiectasia, which can probably be explained by faulty embryologic development. Management of these lesions has been discussed, including brief descriptions of most of the currently accepted treatment methods for these frequently encountered clinical problems.

Adolescent↗
PubMed1979

Facial bone changes with vascular tumors in children.

Deformities of the adjacent facial bones are common with large vascular tumors. Most hemangiomas will resolve spontaneously, but the incidence of resolution appears to be quite low when the adjacent bones are affected. In these, we have used high dosage corticosteroid therapy in the early cases, particularly those involving the orbit. Surgical excision has been used in most of the other cases, with reasonable improvement.

Adolescent↗
PubMed1979

Ventricular wall thickness in the fetal dog.

Ventricular wall thickness of 21 50-to 60-day canine fetuses was determined by direct measurement with calipers. Measurements were made of the left and right ventricular walls and of the interventricular septum, perpendicular to the apico-basilar axis at the location just below the aortic valve, and midway between the coronary sulcus and the apex. Mean determiniations were used to characterize the wall thickne-s at the various levels. The right wall was found to be thickpreciable thickness differences between the septal and left wall at this location. At the level of the midventricular wall, the septal wall thickness exceeded that of the left and right wall. Left and right wall thickness at this level were similar.

Animals↗