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Biomedical subjects

W C Pederson

Publications and source records attributed to W C Pederson.

At least 19 recordsLinked to original sources

Medical and surgical considerations in patients with vasculitis and Raynaud's syndrome.

Vascular problems in the foot are certainly common when one considers only arteriosclerosis on the macrovascular scale. The primary cause of ischemia of the foot undoubtedly is primary arteriosclerosis, whether related to smoking, diabetes, renal failure, or other causes. Vasculitis and vasospasm, in their many forms, are distinctly unusual as a cause of ischemia of the foot. These entities, nonetheless, can cause significant problems from the standpoint of symptoms and even ulceration or gangrene of the foot. This article addresses the pathophysiology of vasculitis and vasospastic problems in the foot and their management.

Foot↗

Replantation.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Describe the indications and contraindications for extremity replantation. 2. Outline the sequence and technique of replantation. 3. Identify potential complications of replantation and recognize treatment options. 4. Assess the results of replantation in terms of function and costs versus benefits.

Contraindications↗

Upper extremity microsurgery.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Understand the indications for free flap coverage of the upper extremity. 2. Know the advantages and disadvantages of the flaps discussed. 3. Have a basic understanding of the anatomy of the flaps discussed. 4. Have a variety of options for free tissue transfer.The application of microsurgical tissue transfer to reconstruction of the upper extremity allows repair of significant bone and soft-tissue defects. Through the years the approach has changed from one of simply getting the wound covered to primary reconstruction to preserve or regain function. A wide variety of free flaps offers the potential to reconstruct nearly any defect of the arm and hand. Vascularized bone transfer can be utilized to repair large bony defects, while innervated free muscle transfer can replace missing muscle function. The total array of flaps and their indications is beyond the scope of a single discussion, but this article focuses on a few flaps that have found application for coverage and functional restoration in the hand and upper extremity.

Arm Injuries↗

Revascularization of the chronically ischemic hand.

Chronic ischemia of the upper extremity can pose challenging problems for the reconstructive hand surgeon. With a combined macro- and microvascular approach, many patients can be offered limb salvage rather than amputation. Direct revascularization probably offers the best approach when it can be attempted. The indirect approaches do offer improvement in most patients and are fairly straightforward. Arterialization of the venous system and free omental transfer should be used with caution by surgeons with little experience in microsurgery, however.

Chronic Disease↗

Ischaemia of the index finger and thumb secondary to thrombosis of the radial artery in the anatomical snuffbox.

We report on nine patients who presented with spontaneous ischaemia of the index finger and thumb over an 11 year period. Arteriography revealed thrombosis of the radial artery in the region of the anatomical snuffbox with evidence of digital artery embolization in each. None had suffered direct trauma to the area or had a demonstrable proximal source for thrombus. While the cause of radial artery thrombosis in our patients in not entirely clear, local inflammation and/or systemic disease may predispose to this entity.

Adult↗

Management of severe ischemia of the upper extremity.

Ischemia of the upper extremity is unusual, particularly in patients without trauma or iatrogenic injury to the vessels of the arm. Some authors have suggested that ischemia of the upper extremity is one sixth as common as that in the leg. Management of patients with vascular trauma or iatrogenic injury is usually straightforward, with direct repair or vein grafting of the injured vessel. Patients with ischemia from vascular disease, however, present a different set of management problems. These individuals often suffer from systemic medical problems that lead to their vascular disease, which is often very severe and accelerated because of the underlying cause. This article discusses the approach to these patients and options for management.

Arm↗

Update on tendon repair.

The past decade has seen some remarkable advances in the management of acute tendon repair, both flexors and extensors. New surgical techniques, such as the epitenon-first technique for flexor tendons, combined with early motion rehabilitation, pharmacologic intervention to prevent adhesions, and noninvasive imaging techniques such as MR imaging to assess repair integrity lead to one inescapable conclusion. Continued evolution in attempts to improve the overall results of tendon injury can only mean that hand surgeons have not yet reached the perfect solution in tendon repair strategy. Much progress has been made since the era of "no man's land" when primary repair in zone II was in disfavor, but many challenges remain to be met if the "perfect" tendon repair is to be realized.

Hand↗

Successful revascularization of a partially avulsed foot in a 6-year-old child.

The foot of a 6-year-old child was revascularized successfully following an avulsion and partial amputation through the tibiotalar joint. Partial degloving had disrupted the anterior and posterior tibial arteries with resultant ischemia. We excised the entire damaged segment of the posterior tibial artery and performed a reverse saphenous vein graft, end-to-end reconstruction of the defect. Peroneal and tibial nerve function returned within 5 months. Four years later, the patient has regained full, painless range of motion and normal strength and sensibility with no evidence of premature growth plate closure or avascular necrosis of the talus.

Ankle Injuries↗

Skin paddle salvage in the fibula osteocutaneous free flap with secondary skin paddle vascular anastomosis.

The fibular osteocutaneous free flap has become a popular choice for the reconstruction of bone and skin defects. A potential drawback has been the reported unreliability of the skin paddle. Previous studies have emphasized total loss of the overlying skin paddle, if the expected perforating vessels are not present either in the intermuscular septum or in the soleus. Two cases are presented in which the skin paddle was found to be supplied by vessels arising from the proximal peroneal artery. there were no intraseptal or intramuscular vessels in the osteocutaneous septum which connected to the overlying skin paddle. The skin island was salvaged by performing independent microsurgical anastomoses of the fibular graft and the skin paddle. Both patients had complete survival of the fibula and overlying skin paddle.

Aged↗

Digital reconstruction by free microvascular transfer of two fingers as a unit from the contralateral paralyzed hand.

The ideal reconstruction for damaged or missing fingers has yet to be achieved. While toe transfer offers an excellent option for reconstruction of the thumb, this type of reconstruction often falls short in replacement of other digits of the hand. Microsurgical transfer of a finger or fingers from the opposite hand offers an option, but is rarely performed due to the morbidity in the donor hand. The case of a patient with a paralyzed, but otherwise normal, opposite hand presents a unique opportunity to repair the contralateral damaged but innervated hand. This case report deals with such a patient in whom two fingers were moved from a paralyzed hand to replace two traumatically missing digits in his previously normal hand. Technical considerations will be discussed and the result at 33 months will be presented.

Adult↗

Donor leg morbidity after pedicled rectus femoris muscle flap transfer for abdominal wall and pelvic reconstruction.

The pedicled rectus femoris muscle and myocutaneous flap has found application for a variety of soft tissue defects of the groin, pelvis, and lower abdomen. Although a number of authors have discussed the usefulness of this muscle flap, few have documented the morbidity from loss of this muscle in the leg. We have studied 7 patients who underwent unilateral rectus femoris muscle transfer, comparing strength of the donor knee to the normal knee. All patients were studied using a computerized dynamometer for strength of knee flexion and contraction. We found that loss of the rectus femoris in patients not undergoing a postoperative program of therapy led to an average decrease in strength about the knee of 24% to 28%, depending on the motion measured. A single patient who underwent an intensive postoperative therapy program had return of normal strength in his donor leg. Despite this common loss of strength, patient complaints were few and the results of reconstruction appeared to outweigh this loss of strength.

Abdominal Muscles↗

Microsurgical management of extremity wounds in diabetics with peripheral vascular disease.

Plastic surgeons are frequently called upon to evaluate wounds in diabetic patients with compromised vascular inflow. Although a few authors have reported success in coverage of such wounds with microsurgical techniques, enthusiasm for this procedure has remained low due to concerns about flap viability, occlusion of flow to the distal limb, and the usually poor systemic status of such patients. We report here on our experience with 19 diabetic patients with peripheral vascular disease and a nonhealing wound of the lower extremity treated over the last 4 years with microvascular tissue transfer. Two patients (10.5 percent) suffered anastomotic difficulties and there was one flap loss (5 percent). Major morbidity rates were acceptable, with only one perioperative death (5 percent) and three cases of nonfatal major systemic difficulties in the immediate postoperative period (16 percent). Despite the importation of well-vascularized tissue, local morbidity at the recipient site was seen in nine patients (47 percent). The overall limb salvage rate was 72 percent during the period of follow-up, which averaged 22 months. Despite this loss of five limbs, all but three of the patients eventually returned to ambulation. The overall death rate in our series was only 2/19 (10.5 percent) over the period of follow-up. Although further work needs to be done in this difficult group of patients to ascertain the long-term benefit (especially relative to the cost/benefit ratio), we feel that this series confirms the safety and short-term efficacy of microsurgical treatment of such individuals.

Adult↗

Osmotic complications of low-molecular-weight dextran therapy in free flap surgery.

Low-molecular-weight dextran is utilized by many microsurgeons after free tissue transfer for its beneficial effects on the microcirculation. While it is generally felt to have a low rate of complications, severe complications secondary to dextran's osmotic effects may occur. We report here on two cases in which therapy with low-molecular-weight dextran was strongly implicated as a causative factor in major complications. These cases and their background are reviewed. Guidelines for the safe administration of this agent in patients post free-tissue transfer are discussed.

Acute Kidney Injury↗

Establishment of normal ranges of laser Doppler blood flow in autologous tissue transplants.

Over a 3-year period, 136 patients were monitored following free autologous tissue transplantation using a laser Doppler flowmeter linked to a computerized data-acquisition system. This monitoring system has indicated perfusion compromise in free flaps more rapidly than clinical observation alone. Most important, this has resulted in an increase in salvage rate from 50.0 to 82.4 percent. In addition, our overall success rate has increased from 92.6 to 97.8 percent since introducing this monitor clinically. Computerization also has facilitated the collection of data, which has enabled us to establish expected values for postoperative blood flow in several types of donor tissues used for microvascular reconstruction. Finally, this computerized monitoring system has relieved personnel from basing decisions on subjective data.

Adult↗

Microsurgical transfer of the greater omentum in the treatment of canine obstructive lymphoedema.

In 13 dogs, experimental obstructive lymphoedema of the lower limb was created by combined radiotherapy and radical groin dissection. Six months later, when the degree of lymphoedema was stable, the lymphatic obstruction was bridged by microvascular insertion of a free omental graft. Six months after grafting, circumferential measurements indicated a statistically significant 38% reduction in the magnitude of lymphoedema. Biopsies showed the omental grafts were alive but contained much fibrous tissue. Lymphatic vessels were identified in 10 of 11 biopsies but connections between these lymphatics and lymphatics proximal to the graft could not be demonstrated by either lymphangiography or dye-injection techniques. The findings indicate that experimental obstructive lymphoedema in the dog can be reduced significantly by insertion of a vascularised omental graft. However, it could not be established that improvement was due to union of graft lymphatics with those of the lymphoedematous limb, although this union may have consisted of lymphatics too small to be demonstrated.

Animals↗

The distally-based radial forearm free flap with valvulotomy of the cephalic vein; a preliminary report.

The radial forearm free flap is widely used in microsurgical reconstruction where a thin, hairless flap is required. While the radial artery may be based either proximally or distally, the venous drainage is generally proximally based in order to provide normal flow through the valves. We have utilised this flap in two patients, based distally on both the radial artery and cephalic vein by removing the valves of the cephalic vein. This technique has been employed widely in peripheral vascular surgery of the lower limb and is called the "in-situ" technique. We have found it to be efficacious in taking a proximal skin paddle, which decreases donor site morbidity and allows for a long vascular pedicle. This paper reports on these two patients and describes the technique of valvulotomy of the cephalic vein.

Adult↗

Pedicled free flaps: indications in complex reconstruction.

Pedicled free flaps are indicated when distant composite tissue is required for wound coverage and adjacent recipient vasculature is unsuitable for microvascular anastomosis. Carrier vessels from a noninjured extremity temporarily nourish the flap while neovascularization between the wound bed and the flap occurs. This process is augmented by intermittent occlusion of the vascular pedicle to prepare the flap for pedicle division. Rigid immobilization must be maintained to prevent avulsion of the flap. Laser Doppler monitoring of the flap during the ischemic training period permits division of the pedicle with confidence. This technique permits transfer of large flaps to compromised wounds with the advantage that the microvascular anastomoses can be performed safely away from the zone of injury. Provided immobilization can be maintained, flaps based on either a lower extremity or wrist carrier can reach virtually any area of the body.

Blood Vessels↗