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Biomedical subjects

E Z Browne

Publications and source records attributed to E Z Browne.

At least 19 recordsLinked to original sources

Evaluation of nerve recovery from minimal-duration crush injury.

The recovery of damaged peripheral nerves has been the subject of multiple studies. The effects of an inadvertent clamping of a nerve has not been well examined. An experiment was performed to evaluate the effects of a minimal-duration crush injury on the rat sciatic nerve and to determine if walking track analysis was useful in evaluating the short-term functional deficit. Ten Sprague-Dawley rats underwent high-pressure, short-duration crush injuries. Walking track analysis was done regularly for 3 weeks. Histological specimens for light and electron microscopy were taken at postoperative days 3, 7, 14, 21, and 42 from similar animals. There was significant decrease in function by the second week, which then improved to control levels after week 3. Toluidine blue and electron microscopic findings confirmed the clinical course, while routine histological findings tended to lag behind the return of function. Walking track analysis appears to be an effective method of evaluating the short-duration nerve crush injury.

Animals↗

Evaluation of a pressure sore model using monoplegic pigs.

This study evaluated a newly developed swine monoplegic pressure sore model by testing the uniformity of the initial wound size. The natural healing also was evaluated. Nine minipigs were used. The hindlimb was denervated by transecting the unilateral nerve roots L1 through S2. At 5 to 14 days, 800 mmHg of pressure was applied to the denervated skin over the trochanteric area with a 3-cm-diameter disk compressing the skin and subcutaneous tissue against the underlying bone for 48 hours. The wound was then debrided of devascularized tissue. Wound surface areas were calculated from photographs. Wound volumes were obtained by measuring the volume of saline needed to fill the wound defect. Full-thickness sores of uniform size developed in all pigs without mortality or complications. Wound surface area and volume increased initially, peaked, and then decreased in an exponential fashion. This model provides a new tool for direct comparison of pressure sore treatment modalities for short- and long-term studies.

Animals↗

Continuous rat intravenous infusion.

Hypovolemic shock and ischemic injury to the graft commonly cause death in small animals after organ transplantation. A venous line must be readily available to replace fluids before fatal complications occur. To establish a venous line, researchers expose a vein by preliminary surgery. This time-consuming procedure adds unnecessary trauma to the recipient and worsens the results. The possibility of long-term fluid transfusion in small animals by serial injections at close intervals is quite limited. We describe a simple technique of continuous i.v. infusion by catheterization of the rat dorsal penile vein with a 24-gauge, 3/4-inch catheter. This easy-to-learn technique has permitted us to establish a venous line quickly without trauma in 148 rats while doing donor and recipient procedures for small bowel and ileocecal segment transplantation. The technique we describe has eliminated one of the most frequent causes of postoperative mortality after organ transplantation-hypovolemic shock. We would like to emphasize that other measures, including avoiding massive bleeding and reducing operative and warm ischemic time, are also very important in preventing this complication. The massive i.v. infusion alone may not totally eliminate hypovolemic shock if other factors are neglected. The use of this technique has allowed us to perform small bowel transplantation with 90% success.

Animals↗

The use of muscle flaps for salvage of failed total knee arthroplasty.

Deep infections occur in 1-5% of all patients undergoing total knee arthroplasty, and may result in failure of the prosthesis and subsequent arthrodesis. Two-stage reimplantation is often successful, but depends upon the presence of good soft tissue coverage. We have treated 9 patients in whom chronic infection developed which required removal of the prosthesis, debridement, and implantation of antibiotic impregnated spacers for control. These patients all had poor quality soft tissue cover precluding prosthesis reimplantation. The use of muscle flaps resulted in 7 of the 9 patients having successful reimplantation of a prosthesis and remaining free of infection in a follow-up ranging from 1-5 years.

Adult↗

Complications of fingertip injuries.

Fingertips are extremely important functional structures, and secondary deformities can cause a great deal of inconvenience if not disability. Injuries to the fingertip must be treated with the same care as is used for all other hand surgery, providing coverage to the tip of the finger with good quality of skin and with the best sensibility possible. By far and away the best method of treatment of complications is their prevention.

Finger Injuries↗

Extremity replantation.

Although the success of replantation and revascularization is in part related to the length of the ischemic interval, it is important to bear in mind that microsurgical intervention must be given appropriate priority relative to the patient's other injuries. Very few patients die as a result of upper extremity trauma. However, the economic, psychologic, and physical debility of a chronic hand injury will be the ultimate handicap in patients who survive multisystem trauma. Therefore, management of the injured extremity has an important place in the overall scheme of trauma care.

Amputation, Traumatic↗

Early dynamic splinting for extensor tendon injuries.

Extensor tendon injuries are traditionally splinted with no motion for 3 to 4 weeks after repair. This may result in limitation of flexion because of extensor tenodesis at the site of repair. To prevent this, we used a dynamic splinting program opposite to the one that is used for flexor tendon repair, with an outrigger splint holding the fingers in extension and allowing full active flexion. Fifty-two patients who had extensor tendon repairs in the area from the wrist to the middle of the proximal phalanx were treated. Motion was begun 2 to 5 days after repair and was continued for approximately 5 weeks. No tendon ruptures occurred, and all patients recovered full flexion.

Adult↗

The relationship of the extrinsic blood supply to regeneration in graft reconstructed peripheral nerves.

Median nerves of rats were reconstructed with conventional or vascular nerve grafts. After 2, 3 and 4 weeks, Allen Video-Enhanced Contrast, Differential Interference Contrast (AVEC-DIC) microscopy revealed axonal transport in most preparations, with varying degrees of myelination. Radio-isotope tracer was measured in the nerve. Two and 4 week measurements revealed no difference between the graft types. At 3 weeks the vascular graft group exhibited transport along the entire length of the nerve in contrast to a relatively abbreviated path length in the conventional graft group. Nerve conduction velocities (NCV) were measured proximal to, within and distal to the grafts. Three week NCV showed no difference between the graft types. The 4 week NCV revealed normal values in the vascular graft group at points distal to and within the graft. Significant slowing was seen in the conventional grafts at both points.

Animals↗

Infraclavicular median nerve compression caused by a lipoma.

The most common site of median nerve compression is in the carpal tunnel, the most common of all entrapment neuropathies. Less frequent entrapment neuropathies of the median nerve include the anterior interosseous and pronator syndromes in the proximal forearm. Even less commonly seen is entrapment at the infraclavicular segment of the brachial plexus. Median nerve compression at the level of the axilla has been reported as being caused by anomalous axillary arch muscles, anomalous vascular perforations of the nerve or its roots, the pectoralis minor muscle, and a thickening of the deltopectoral fascia. To the authors' knowledge, this is the first report of compression at that level by a benign tumor.

Clavicle↗

Complications of skin grafts and pedicle flaps.

Skin coverage complications of hand wounds can be divided into two categories: those associated with problems of the wound bed itself and those associated with failure of the skin graft or flap coverage. Wound problems generally are the result of inadequate preparation, infection, or excess scarring due to a long interval between injury and time of coverage. If the wound is adequately debrided, removing all devitalized tissue or tissue colonized with bacteria, coverage can usually be undertaken no later than 3 days after injury. Injuries that result in loss of skin only are best treated with skin grafts. If the bed is well vascularized, complications generally are only mechanical ones, either establishment of a barrier such as hematoma between the bed and the graft, or shearing forces tearing the graft from the bed. Skin flaps carry their own blood supply so they are not generally subject to those kinds of complications; but they are dependent upon continuation of adequate circulation until vascularization takes place. Because they are much thicker than grafts, this is a slower process, and the flap is vulnerable to problems of kinking or tension of the base. Careful attention must be paid to prevention of these problems, especially in the first few days. Axial flaps are preferable to random ones, but any flap must be carefully planned in order to assure adequate vascular perfusion and minimal tension.

Cicatrix↗

Prevention of extensor lag after indicis proprius tendon transfer.

An experiment on fresh cadaver hands showed that a longitudinal incision of the hood did not affect index extension when traction was made on the common extensor tendon, but that excision of a portion of the hood containing the indicis proprius caused an extensor lag. The lag was eliminated by repair of the hood, providing that the closure was not too tight to prevent normal excursion of the hood. These findings were correlated with findings in patients who had undergone indicis proprius tendon transfer. Extensor lag after indicis proprius transfer is not caused by removal of the force of the tendon per se, but by factors which cause either disruption of normal hood function or tethering of its normal excursion.

Cadaver↗

Method for measurement of circumduction of the thumb to evaluate results of opponensplasty.

A simple method for measuring circumduction of the thumb, by using a ratio of the range of motion to the length of the first metacarpal, is described. This method can be of value in assessing many aspects of thumb function, especially the improvement in function after opponensplasty. The improved ability to position the thumb in a useful location, both for pinch and grasp, appears to correlate well with the patient's use of the hand for previously impossible tasks.

Humans↗

Burn syndactyly.

When the entire digital web space has been destroyed by burn scarring and there is a contracture of the volar aspect of the web as well as the dorsum, Z-plasties and skin grafts alone seldom produce a satisfactory web space. During the past 3 years, for the release of 46 contracted web spaces in 20 burned patients, we have turned a rectangular flap from the dorsal surface of the web through into an inverted-T incision in the palm. The adjacent sides of the defects have been skin grafted. In all these patients, we obtained satisfactory release of the contracture and restoration of the web space.

Burns↗

Ski pole thumb injury.

Disabling injuries can occur in the area of the MP joint of the thumb when a skier falls against the planted ski pole while holding the ski strap in the usual fashion. This is presently the most common ski injury of the upper extremity. It is important to determine if instability has resulted, because there may be disruption of the ulnar aspect of joint capsule as well as of the extensoradductor hood mechanism. If this has occurred, it is immediately to prevent the development of the chronic "gamekeeper's thumb."

Athletic Injuries↗

Carpal tunnel syndrome caused by hand injuries.

Although carpal tunnel syndrome associated with injury to the wrist is common, it is possible to overlook symptoms of median nerve compression caused by an ascending tenosynovitis secondary to trauma distal to the wrist. One should look for these symptoms in such patients who complain of pain and weakness of the hand, and release the carpal tunnel if nerve compression is suspected.

Carpal Tunnel Syndrome↗