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Biomedical subjects

W F Blair

Publications and source records attributed to W F Blair.

At least 19 recordsLinked to original sources
PubMed1995

Results of combined internal and external fixation for the treatment of severe AO-C3 fractures of the distal radius.

Combined internal and external fixation for distal radius fractures has been previously reported, but the indications, technique, and results are not defined. This study reviews an experience with a specific surgical strategy for the treatment of a homogeneous population of AO-C3 fractures of the distal radius. The technique is composed of combined palmar and dorsal surgical approaches for open reduction and internal fixation of fracture fragments after neutralizing the wrist with a rigid external fixator. Thirteen fractures in 12 patients were followed an average of 27 months. Wrist motion averaged 60 degrees of flexion and 45 degrees of extension. The injured extremities had a mean grip strength that was 83% of the uninjured side. Follow-up x-ray films showed a dorsal tilt of 1 degree, radial inclination of 18 degrees, and radial length of 12 mm. Using the rating system of Green and O'Brien, the results were excellent or good in 10 wrists. The results indicate that this surgical strategy, though technically demanding, can be successfully used in this specific subset of difficult to treat distal radius fractures.

Adult↗
PubMed1994

Acute effects of smoking on digital artery blood flow in humans.

Smoking induces several immediate physiologic changes in the distal arteries of the human upper extremity. We examined the hemodynamic effects of cigarette smoking on blood flow in normal human digital arteries using 20 MHz pulsed ultrasonic Doppler velocimeter methods. In each of nine subjects, two presmoke measurements and six postsmoke measurements were collected over a 30-minute period. Maximum velocity and volumetric flow data were averaged. Although no statistical differences were present between presmoke and postsmoke variables, maximum velocity decreased 14% and volumetric flow decreased 60% in the first postsmoke measurement interval. These observations suggest that smoking produces increased vascular resistance in the fingers and an overall reduction in both volumetric blood flow through arteries and tissue perfusion.

Adult↗
PubMed1993

Anatomy of the oblique retinacular ligament of the index finger.

The available literature includes conflicting descriptions of the anatomy and function of the oblique retinacular ligament. We have studied this ligament in the index finger to better define its presence, configuration, points of attachment, length, and relationship to the proximal interphalangeal joint axis. Twenty fresh frozen index fingers were dissected. Five additional specimens were decalcified, mounted, sectioned transversely at 1 mm intervals and studied under the microscope. An oblique retinacular ligament was identified on the radial side of the index finger in 95% and on the ulnar side in 90% of the specimens. The radial oblique retinacular ligament was usually longer and more developed than the ulnar oblique retinacular ligament. Proximally, the ligament arose from the middle third of the proximal phalanx and the A-2 pulley whereas, distally, it inserted into the lateral extensor band with a fan-shaped expansion centered 4 to 6 mm distal to the proximal interphalangeal joint line. In 70% of the specimens, the oblique retinacular ligament was supplemented by a contribution from the proximal cruciform pulley (C-1). Histologic cross sections also confirmed the presence of the oblique retinacular ligament but not the supplemental contribution arising from the C-1 pulley. The relationship of the oblique retinacular ligament to the proximal interphalangeal joint axis is dependent on the proximal interphalangeal joint position; the ligament lies palmar to the proximal interphalangeal joint axis only when the proximal interphalangeal joint is flexed.

Cadaver↗
PubMed1992

Bilateral spontaneous extensor tendon ruptures in Madelung's deformity.

Rupture of finger extensor tendons by attrition is an extremely rare complication of Madelung's deformity. We report a case of bilateral rupture in a previously symptom-free woman. The dorsally subluxed distal ulna was resected to prevent further rupture. The mechanism of injury, clinical and radiographic features, and treatment of this uncommon complication are reviewed.

Aged↗
PubMed1992

Extensor tendon injuries.

A thorough knowledge of anatomy, injury patterns, repair techniques, and evolving rehabilitation methods is necessary to best treat extensor tendon injuries. These injuries are conceptualized as occurring in one of eight zones, which are numbered distally to proximally in the hand and forearm. Even though surgical technique and rehabilitation are specific in each zone, injuries over and proximal to the proximal interphalangeal joint tend to yield less satisfactory results. Dynamic postoperative extension splinting is one factor that is improving long-term results.

Hand Injuries↗
PubMed1991

Digital periarterial sympathectomy for ischaemic digital pain and ulcers.

Digital periarterial sympathectomy was performed on 11 digits in three patients with chronic digital ischaemia which was a manifestation of either Raynaud's disease, C.R.E.S.T. syndrome or traumatic ulnar artery thrombosis. Before operation, all patients had pain in the affected fingers and five digits had ulcers, two of which were infected. Using the operating microscope, the adventitia was stripped circumferentially over the distal 2 cm. of the common digital arteries, the bifurcation and the proximal 1 cm. of the proper digital arteries distal to the bifurcation. The same procedure was repeated, at the wrist level, for the ulnar artery and/or the radial artery and its dorsal branch. Follow-up ranged from three to 16 months. After two weeks, all patients reported relief of pain and the ulcers were progressively healing. By three months, all ulcers had healed.

Adolescent↗
PubMed1991

Long-term follow-up of primary flexor pollicis longus tenorrhaphies.

This study retrospectively analyzes primary flexor pollicis longus repairs. Ninety-four patients were identified and had extensive chart review. Thirty patients returned for follow-up (mean of 6.8 years) interview, range of motion, and strength testing. At follow-up, interphalangeal active range of motion, metacarpophalangeal active range of motion, and carpometacarpal active range of motion was 68 degrees, 48 degrees, and 46 degrees, respectively. Comparisons between active range of motion for the injured and noninjured hands revealed percentage differences of 71, 82, and 96% for the interphalangeal, metacarpophalangeal, and carpometacarpal joints. The percentage differences between active range of motion and passive range of motion for the injured metacarpophalangeal and interphalangeal joints were 71% and 75%. Injured thumbs had averages of 6.7, 7.0, 5.4, and 30.6 kg for the key, chuck, thumb-index pinches and JAMAR grip mean. The percentage differences of injured to uninjured hands in these tests were 91%, 84%, 92%, and 92%. Factors that appear to have a consistently negative effect on outcome include mechanism of injury and associated damage. Factors that did not uniformly affect outcome included zone of injury, age, sex, and postoperative splinting.

Adolescent↗
PubMed1991

Transcutaneous blood flow measurements in arteries of the human hand.

Technical advances in twenty MHz pulsed ultrasonic Doppler velocimetry (PUDVM) permit increasingly accurate measurements of blood flow in small vessels. This study applied advanced twenty MHz PUDVM methods to the transcutaneous, noninvasive quantitation of blood flow in arteries of the human hand. One hundred forty-four measurements were completed bilaterally in the digital arteries of all fingers and in the distal radial and ulnar arteries of the forearm. The data were averaged by artery for maximum velocity and average volumetric flow. The maximum velocity for digital and forearm arteries was about 20 centimeters per second and 50 centimeters per second, respectively. The average volumetric flow for these same arteries was about 0.02 cubic centimeters per second and 0.18 cubic centimeters per second, respectively. Statistical analysis demonstrated no differences between paired, contralateral arteries; within given fingers a difference occurred only between the radial and ulnar arteries of the index finger.

Adult↗
PubMed1990

Flow field mapping in the anesthetized rat.

This study measured the hemodynamics of peripheral arterial sites in the rat, using 20 MHz pulsed ultrasonic Doppler velocimeter (PUDVM) methods. The lower extremities of 14 male Sprague-Dawley rats were studied. The targeted sites included the abdominal aorta, external iliac, proximal femoral, mid-femoral, and saphenous arteries. The hemodynamic variables of pulse period, maximum centerline velocity, lumen diameter, and mean volumetric flow were calculated interactively from temporal-spatial plots of local velocity distributions. An analysis of variance revealed significant differences between right and left sides for lumen diameter (P = 0.028) and mean volumetric flow (P less than 0.0001). The analysis showed no statistical difference for pulse period (P = 0.0836) among sites. However, three distinct groupings of sites: 1) abdominal aorta, 2) external iliac, proximal femoral, and mid-femoral arteries, and 3) saphenous artery were noted for the remaining hemodynamic variables (P less than 0.05). These results indicate that three hemodynamically distinct regions are available for microvascular research in the rat lower extremity arterial tree.

Anesthesia, General↗
PubMed1990

Long-term results of extensor tendon repair.

A retrospective analysis was done in 62 patients with 101 digits having extensor tendon injury. Quality of outcome and parameters that might influence outcome were evaluated. The majority of patients were treated with conventional static splinting. Sixty percent of all fingers sustained an associated injury (fracture, dislocation, joint capsule or flexor tendon damage). Patients without associated injuries achieved 64% good/excellent results, and total active motion of 212 degrees. This difference was statistically significant (p less than 0.05). Distal zones (1 to 4) had a significantly poorer result than more proximal zones (5 to 8). The percentage of fingers losing flexion was greater than the percentage of fingers losing extension. In addition, the average degree loss of flexion was greater than the average degree loss of extension. This would seem to indicate that loss of flexion may be a more significant complication from extensor tendon injury than previously thought.

Adolescent↗
PubMed1990

A role delineation study of hand surgery.

In 1986, The American Association for Hand Surgery and the American Society for Surgery of the Hand jointly sponsored a Role Delineation Study of Hand Surgery. The purpose of this study was to define the knowledge and skills necessary for competent hand surgery practice and to determine the responsibilities and activities of hand surgeons. Eight hundred thirty-eight hand surgeons returned a self-report questionnaire. This questionnaire was designed to collect information relative to the demographic characteristics of the respondents, the importance of 38 surgical procedures, and 60 categories of knowledge related to hand surgery, and to elicit respondents opinions regarding certification in hand surgery. This study is a first attempt to define the domain of hand surgery. The data collected in this study provide the basis for designing residency fellowship and continuing education programs and may also be used to study manpower needs, regional variations in practice patterns, and to identify the educational needs of the profession of hand surgery.

Education, Medical↗
PubMed1990

Schultz metacarpophalangeal arthroplasty: a long-term follow-up study.

We describe a prospective, long-term evaluation of the Schultz metacarpophalangeal joint implant. The prosthesis is a semiconstrained, cemented implant with a ball-in-socket articulation. Thirty-six implants were followed for an average of 10.9 years. There was a progressive decrease in range of motion and strength and a recurrence of ulnar deviation. The neck of the proximal phalangeal component fractured in 39% of the joints. Periarticular heterotopic bone formed in all joints, but was extensive in only 22%. Although some lucency of the bone-cement interface was seen in 80% of the joints, no prosthetic loosening occurred in this series. Our results indicate that long-term, intramedullary cement fixation of relatively long-stemmed components can be satisfactory. However, the articulated portion of this implant does not consistently withstand the stresses transmitted across the joint and does not provide long-term joint stability.

Adult↗
PubMed1989

A microvascular anastomotic device: part I. A hemodynamic evaluation in rabbit femoral arteries and veins.

This study quantitatively assesses the hemodynamic consequences of inserting a 1.5-mm polyethylene anastomotic device in both small arteries and veins. The device was placed in 20 rabbit femoral arteries and 20 femoral veins. Using 20-MHz pulsed ultrasonic Doppler velocimetry techniques, blood flow was measured in 5 immediate postoperative intervals and at the 24-hour and 3-week postoperative intervals. In arteries, volumetric flow (Q) was not statistically different in any postoperative interval; maximum spatial velocity (Vmax) was significantly increased in the immediate postoperative intervals but was not different at 24 hours or 3 weeks. In veins, significant decreases in Q and increases in Vmax occurred in the immediate postoperative intervals, but differences were not noted at the 24-hour or 3-week intervals. The results of this study indicate that the hemodynamic consequences of anastomosing small vessels with a polyethylene device are minimal and that this mechanical technique is an effective method for experimental microvascular repairs.

Anastomosis, Surgical↗
PubMed1989

A microvascular anastomotic device: Part II. A histologic study in arteries and veins.

This study analyzes the histology associated with the polyethylene ring-pin device. The device was placed in 20 rabbit femoral arteries and 20 femoral veins. Specimens were harvested at 24-hour and 3-week postoperative intervals and were analyzed using light, scanning electron, and transmission electron microscopy. Generally, the reparative process in the arteries and veins was similar. In 24-hour artery and vein specimens, the endothelial cells were absent, the media tapered within the device, but smooth muscle cells (SMC) remained partially viable. In 3-week specimens, the device junction was well healed and reendothelialized. Subintimal hyperplasia was present, the internal elastic lamina was not reconstituted, and the SMCs were partially viable. Small vascular channels formed at the device junction, and small venous valves were noted near the device. Macrophages lined the margins of the device. The early reparative process proceeds favorably, by histologic criteria, after vessel repair with the polyethylene ring-pin device.

Anastomosis, Surgical↗