Graft vasculopathy in clinical hand transplantation.

Allogeneic hand transplantation is now a clinical reality. While results have been encouraging, acute rejection rates are higher than in their solid-organ counterparts. In contrast, chronic rejections, as defined by vasculopathy and/or fibrosis and atrophy of skin and other tissues, as well as antibody mediated rejection, have not been reported in a compliant hand transplant recipient. Monitoring vascularized composite allograft (VCA) hand recipients for rejection has routinely involved punch skin biopsies, vascular imaging and graft appearance. Our program, which has transplanted a total of 6 hand recipients, has experience which challenges these precepts. We present evidence that the vessels, both arteries and veins may also be a primary target of rejection in the hand. Two of our recipients developed severe intimal hyperplasia and vasculopathy early post-transplant. An analysis of events and our four other patients has shown that the standard techniques used for surveillance of rejection (i.e. punch skin biopsies, DSA and conventional vascular imaging studies) are inadequate for detecting the early stages of vasculopathy. In response, we have initiated studies using ultrasound biomicroscopy (UBM) to evaluate the vessel wall thickness. These findings suggest that vasculopathy should be a focus of frequent monitoring in VCA of the hand.

Late-preconditioning protection is evident in the microcirculation of denervated skeletal muscle.

We investigated whether ischemic preconditioning induces microvascular protection in skeletal muscle at the late phase (after 24 hours) when the same muscles are subjected to prolonged warm global ischemia. The cremaster muscle of the male Sprague-Dawley rat underwent vascular isolation and was subjected to 4 hours of ischemia and 60 minutes of reperfusion. Early preconditioning consisted of 45 minutes of ischemia followed by 15 minutes of reperfusion before prolonged ischemia/reperfusion; late preconditioning also consisted of 45 minutes of ischemia but was done 24 hours (24-hour period of reperfusion) before the prolonged ischemia/reperfusion. Arteriole diameters and capillary perfusion were measured with use of intravital microscopy. Four groups were compared: rats that underwent early preconditioning, their controls, rats that underwent late preconditioning, and their controls. Early and late preconditioning significantly attenuated vasospasm and capillary no-reflow compared with the controls for each. Average arteriole diameter was significantly larger in the rats that underwent late preconditioning than in any other rats; it was also significantly larger in the controls for late preconditioning than in those for early preconditioning. We introduce a model of the rat cremaster muscle that has been isolated from its vascular supply as a useful preparation to study the effects of late preconditioning on microcirculation in skeletal muscle. Late preconditioning provided better microvascular protection than did early preconditioning. The mechanism for this preconditioning protection is being investigated because it should provide a means for therapeutic intervention.

Management of the traumatized joint of the finger.

Selection of the reconstructive technique for the traumatized joint requires a careful consideration of the condition of the injured and adjacent joints, the needs and desires of the patient, and an understanding of the advantages and disadvantages of the available options. The MP joint is the key to a useful arc of motion, providing 77 per cent of the total arc of flexion. Every effort should be made to preserve its maximum pain-free movement. PIP joint motion, although important in maintaining grip strength, can more readily be sacrificed to provide stability when MP joint motion is normal. Arthrodesis provides a pain-free stable joint with a sacrifice of motion. It may be indicated in young patients in whom heavy loading is likely; in joints with a fixed, painful deformity, instability, or loss of motor; and in the salvage of failed implant arthroplasty. Arthrodesis is generally contraindicated where physes are open. PIP joint arthrodesis is well tolerated in the index finger with minimal morbidity. Motion of MP joints and PIP joints of the long, ring, and small fingers, however, should be preserved using other techniques when possible. Resection arthroplasty may be useful in selected cases of post-traumatic arthroplasty where other treatment techniques are not available. Soft tissue interposition techniques are useful in specific cases. Eaton volar plate arthroplasty provides good results where 50 per cent of the articular surface is preserved. The technique, however, requires precision to avoid rotational malalignment. Perichondrial resurfacing provides a reasonable alternative in patients younger than 40 years of age who have a relatively well maintained joint contour, preferably involving a single joint surface. Prior infection is a relative contraindication. MP joints generally produce better results than PIP joints. Swanson interposition arthroplasty remains the most widely accepted implant technique, providing improved stability and earlier motion than simple resection arthroplasty. Reported arcs of motion range from a minimum of 29 degrees to a maximum of 85 degrees, with results generally better for MP than for PIP joints. Complications are common and include implant fracture, lateral instability of the PIP joint, and, occasionally, synovitis. Patient satisfaction, however, has been consistently reported as high. The use of Swanson arthroplasty in acute cases remains controversial, although several authors report favorable results. Silicone arthroplasty is contraindicated in joints with open physes. Allograft small joint reconstruction provides replacement bone and articular surface without donor site morbidity. Experience with the technique, however, has been limited. Increasing concern over the transmission of infectious diseases may make this option less desirable.(ABSTRACT TRUNCATED AT 400 WORDS)

Toe-to-thumb transfer: a new technique.

Our technique combines the advantages of two proven techniques of the wraparound flap and vascularized joint transfer while offering a more normal thumb, both functionally and cosmetically. Its advantages are as follows: 1. A more normal-looking thumb with good length 2. Preservation of motion through joint transfer 3. Maintenance of growth potential through transfer of vascularized epiphyses 4. Minimal donor-site morbidity

Free vascularized transfer of the metatarsophalangeal and proximal interphalangeal joints of the second toe for reconstruction of the metacarpophalangeal joints of the thumb and index finger using a single vascular pedicle.

Previously described double-joint transfers from a single toe have required a separate vascular pedicle for each joint transferred. In this case report, however, we describe the use of a single vascular pedicle to perform a free vascularized double-joint transfer of the metatarsophalangeal and proximal interphalangeal joints of a single toe to the metacarpophalangeal joints of the thumb and index finger. Although a pollicization could have restored adequate function to the patient's hand, she desired five digits. Given the increased distance between the metacarpophalangeal joints of the thumb and index finger, an increased interjoint pedicle length was needed. We obtained this by mobilizing the digital vessels away from the joints of the second toe. This involved transecting the tibial digital vascular branches of the proximal interphalangeal joint and the fibular vascular branches of the metatarsophalangeal joint. Based on a single pedicle, the vascularity of the proximal interphalangeal joint was maintained by preserving the distal commissural vessels at the distal phalanx. Advantages of this technique include using a single donor artery and reconstruction of two metacarpal joints with a single toe.

Microvascular reconstruction of the foot: weight-bearing patterns, gait analysis, and long-term follow-up.

Between 1980 and 1989, 46 free-tissue transfers (32 skin flaps, 14 muscle flaps) were performed in 44 patients for foot reconstruction. Patient age averaged 25.8 years (range 2 to 74 years). Length of follow-up averaged 43 months. Flap survival rate was 96 percent. Debulking was done in 16 skin and 8 muscle flaps. The ulceration rate in 25 patients with weight-bearing flaps was 32 versus 11 percent in 19 patients with non-weight-bearing flaps. Time before ambulation averaged 6.4 months following weight-bearing reconstruction and 4.5 months following non-weight-bearing reconstruction. All patients with either abnormal foot-mat diagrams or major gait abnormalities had significant underlying radiologic foot abnormalities or nerve injuries. We conclude that both skin and muscle free flaps frequently need secondary debulking procedures to improve function. The ulceration rate tends to be higher in weight-bearing flaps than in non-weight-bearing flaps. Underlying bony architecture and nerve function affected weight-bearing patterns and gait more than type of wound coverage.

Reconstruction of the hand with free microneurovascular toe-to-hand transfer: experience with 54 toe transfers.

Over a period of 6 years, 54 toe-to-hand transfers were performed, 24 for thumb and 30 for finger reconstruction. Refinements in evaluation, preparation, and surgical technique are detailed. Forty-nine toes (90.7 percent) survived. Exploration was required for circulatory compromise following 13 transfers (34.2 percent), to good effect in 9 (69.2 percent). Secondary surgery was performed in 26 cases, consisting of tendolysis, osteotomy, and deepening of the first web space. Review was undertaken at an average of 1 year and 9 months after transfer. Power grip averaged 28.5 percent of the normal hand and pinch strength 26.6 percent, great toe transfer giving 35.7 percent and second toe transfer to thumb giving 15.6 percent strength compared with normal. Static two-point discrimination of less than 10 mm was present in 37.5 percent of those studied under 2 years after surgery and in 75 percent of those studied more than 2 years later. The choice of procedure for thumb reconstruction is discussed in detail, as are supplementary skin cover, vascular considerations, and the high exploration rate.

Complications and vascular salvage of free-tissue transfers to the extremities.

Complications were examined in 122 free flaps to lower and upper extremities in 104 patients, and vascular salvage was examined in 182 free flaps to lower and upper extremities in 158 patients. All patients were treated by the same surgeon. The overall survival rate of flaps was 96 percent. Complications occurred in 22 percent of the flaps. Complication rates were lower in patients with one free flap than in patients with two. Flaps had more vascular complications than nonvascular. Accompanying skin islands were found to be necessary to monitor vascularized bone transfers in order to avoid flap failure. Flow in the pedicle was reestablished in all flaps, but a higher percentage of flaps with longer ischemic times were lost. Although vascular compromise occurred frequently (15 percent), prompt surgical exploration and reexploration were thought to have greatly increased free-flap survival.

Functional results of vascularized versus nonvascularized nerve grafting.

Functional results of vascularized nerve grafts (VNG), end-to-end (E-E) repair, and nonvascularized nerve grafts (NNG) were compared using 75 rats. For all three groups, the sciatic function index (SFI) was measured for 12 weeks. For the vascularized nerve graft and nonvascularized nerve graft groups, it was measured every 4 weeks to week 36. The vascularized nerve graft and end-to-end repair groups showed significantly better recovery than the nonvascularized nerve graft group 4 weeks after surgery, and this pattern continued throughout the experiment. Results from the vascularized nerve graft and end-to-end repair groups did not differ significantly. Twelve weeks after surgery, morphologic and electrophysiologic assessments were used to compare the experimental and contralateral legs. The vascularized nerve graft group showed significantly better recovery than the nonvascularized nerve graft group on all measures except muscle weight and axon count, even though the grafts were completed in a normal bed.

Blood flow and tissue survival in the rabbit venous flap.

The extent of venous flow, revascularization, local fluid imbibition, and metabolic status was evaluated in an experimental venous flap model. Thirty-six rabbits divided into six groups of six rabbits each had a 3.5 x 2.5 cm venous flap elevated along the thoracoepigastric vein, connected only by its proximal and distal vein, and sutured back. A composite graft of the same size was created on the contralateral side. Venous flaps survived 14 days, while composite grafts consistently did not. The vascular network was partially filled with fluorescein tracer within an hour after flap creation, even with an underlying Silastic sheet. Filling improved over several days, consistent with rapid revascularization. Composite grafts showed no immediate filling and delayed revascularization. Venous flow was apparently insufficient to enhance metabolism, since both glucose and lactate levels were equivalent between venous flaps and composite grafts. This supports the concept that an enhanced revascularization may be the primary mechanism of survival for venous flaps.

Salvage replantation of lower limb amputations.

Three cases are reported in which the microsurgical salvage of parts of traumatic lower extremity amputations associated with degloved proximal skin loss provided sturdy, sensate skin and soft-tissue coverage and thereby preserved functional below-knee amputation levels. In two instances, a free innervated filletted flap was constructed from the foot of the amputated limb, and in the third case, the amputated lower leg was shortened, successfully replanted, and followed later by elective amputation of a foot at the Syme level. At a mean follow-up of 2 years, all three patients are ambulating well in below-knee prostheses.

The ability of oxygenated fluorocarbon solution to minimize ischemic skeletal muscle injury.

The amputated canine limb was used to create a devascularized skeletal-muscle-containing model. The extremity was perfused with one of several solutions or merely cooled as a preservative measure during the devascularized period and then replanted. Perfusion of the limb with oxygenated fluorocarbon solution minimized edema formation and leakage of skeletal muscle enzymes into the serum following revascularization as compared to the other perfusates or to mere cooling. Histopathologic changes within the revascularized muscle were also minimized by the oxygenated fluorocarbon perfusion. It is probable that these findings will correlate with improved function of replanted extremities or free muscle flaps. The applicability of these findings to human extremity replantation and free-flap transfer is postulated. However, long-term human studies will be necessary to assess the function of extremities and flaps perfused with this solution prior to its general use in extremity replantation and free-flap transfer.

Experimental replantation of canine forelimbs after 78.5 hours of anoxia.

To assess the effect of ischemia on osteocyte survival and longitudinal growth in bone, one forelimb of eight puppies and seven dogs was amputated, perfused with iced Collins solution, maintained at 4 degrees C for 72 hours (78.5 hours total anoxia), and replanted. Five puppies were kept for 1 year to assess bone growth. Undergoing bone labeling on days 1, 8, and 15, the other animals were sacrificed at 22 days to assess osteocyte survival. Osteocytes survived replantation in all dogs and one puppy; most osteocytes died in two puppies. In five long-term puppies, central epiphyseal growth was disturbed, but the peripheral portions maintained nearly normal growth, with almost normal bone length being achieved at 1 year.

Regeneration following rejection of peripheral nerve allografts of rats on withdrawal of cyclosporine.

Sequential changes in the sciatic nerve function and morphology were evaluated in transplanted nerve allografts from ACI-RT1a into Lewis RT1I rats after withdrawal of cyclosporine, which had been administered subcutaneously daily (5 mg/kg) for 12 weeks. Experimental groups were established as follows: (1) allograft with cyclosporine (evaluated and sacrificed at 12, 14, 16, 20, 24, and 36 weeks, 10 rats at each week), (2) allograft without cyclosporine (12 and 24 weeks, 10 rats at each week), (3) isograft with cyclosporine (12 and 24 weeks, 6 rats at each week), and (4) isograft without cyclosporine (12 and 24 weeks, 10 rats at each week). Regeneration was evaluated through walking track analysis, electrophysiologic studies, weight of the anterior tibial muscle, and axon counts, diameter, and myelin thickness. Regeneration was observed through 14 weeks after grafting; by 16 weeks, all rats had demonstrated a clear rejection phase, but regeneration indices then recovered quickly by 24 weeks. Electron microscopy of both the graft and distal nerve suggested that both Schwann cells and axons were affected by the rejection phenomenon. Allografts without cyclosporine showed inferior regeneration histologically at 24 weeks. Morphologically, allografts were equivalent to isografts treated with cyclosporine at 24 weeks. Although nerve allografts are rejected after cyclosporine withdrawal, they may still serve as effective nerve conduits.

The effect of hypothermia and tissue perfusion on extended myocutaneous flap viability.

The salutary effect of hypothermia and tissue perfusion on extending the ischemic tolerance of the canine latissimus dorsi myocutaneous flap was demonstrated in this experimental study. A total of 175 flaps from 89 adult mongrel dogs were elevated with one-half the flaps perfused with iced Collins renal preservation solution. With the exception of control flaps kept at ambient temperature, the remaining flaps were stored at 4 degrees C for periods ranging from 24 to 192 hours followed by transplantation into the groins of recipient dogs, with anastomosis of the thoracodorsal artery and vein in an end-to-side manner to the femoral artery and vein, respectively. The study was divided into two distinct sections. The acute phase involved the transplantation of 77 flaps into random recipient dogs, and following a 3-hour period of systemic perfusion, the flaps were removed, weighed, and sectioned for later histologic study. Progressive increase in flap weight was observed up to 96 hours of hypothermia with a sharp decline in weight at 120 hours of hypothermia. The increase in flap weight in the nonperfused flaps was significantly greater than the previously perfused flaps. Histologically, at 120 hours of hypothermia, loss of vascular integrity was noted, suggestive of a no-reflow phenomenon. In the second, or extended-flap, study, 98 flaps were transplanted into the groins of the original donor animal and allowed to remain in situ for a 2-week period. The flaps were then carefully observed for viability, removed, and sectioned for histologic study. Hypothermic support of up to 96 hours extended viability in both perfused and nonperfused flaps, although beyond this hypothermic period viability was seen only in previously perfused flaps. The clinical implications of this study include hypothermic perfusion of a major-extremity amputation prior to replantation or the temporary storage of a free myocutaneous flap.

Survival and blood flow evaluation of canine venous flaps.

Using a canine model, we compared postoperative viability of saphenous venous flaps, cephalic venous flaps, and composite-tissue grafts without vascular connections. Of the saphenous flaps, 14 percent survived. Of the flaps based on the cephalic vein, 75 percent survived. Cephalic composite-tissue grafts were 13 percent successful. The presence of a more intricate venous plexus in a flap seems to increase its chances of success. Arterial injections of radioisotope-labeled microspheres were used to chart revascularization in cephalic flaps. These flaps demonstrated arterial blood flow by day 3, while the composite grafts showed no flow until day 7. Venous injections of microspheres distal to the flap were used to test vein-to-capillary blood flow. No significant entrapment of microspheres within the flaps occurred at any time, suggesting such flow to be inadequate.

Thumb replantation: survival factors and re-exploration in 122 cases.

We analyzed 122 cases of replantation following complete amputation of the thumb and correlated various factors with rates of survival. The overall survival rate of thumb replantation was 71%. The type of amputation markedly affected survival rate. In minimally damaged amputations, the time period from injury to the start of surgery was the only significant factor related to survival. Other factors such as age, smoking history, amputation level, the number of vessels reconstructed and the method used did not relate statistically to survival. With avulsion amputations, the survival rate of replantation at and proximal to the MP joint was significantly better than replantation distal to the MP joint. 20 thumbs required re-exploration for vascular compromise; nine of these were salvaged (45%).

Repair of chronic subluxation of the distal radioulnar joint (ulnar dorsal) using flexor carpi ulnaris tendon.

Chronic dislocation of the distal radio-ulnar joint is usually treated conservatively or by resection of the ulnar head (the Darrach procedure). Recently there has emerged a trend towards reconstructive stabilization procedures, based on modifications of old methods. This article describes a stabilization procedure for correction of chronic subluxation of the distal radio-ulnar joint (ulnar-dorsal) using the flexor carpi ulnaris tendon. A series of five patients is presented together with a historical review of the development of reconstructive approaches in this area.

A transverse skin incision approach for decompression of pronator teres syndrome.

Pronator teres syndrome is a compressive neuropathy of the median nerve in the proximal part of the forearm and distal part of the arm. The outcome of surgical decompression is occasionally unsatisfactory because of a poor scar. We present the use of a transverse skin incision that allows adequate exploration and decompression distally and proximally, beneath the subcutaneous tissue beyond the volar elbow crease.

A neurovascular island flap for volar-oblique fingertip amputations. Analysis of long-term results.

A neurovascular island flap has been developed to reconstruct volar-oblique fingertip amputations. This study analyzes the data collected on 16 patients who were treated with this flap and had at least 2 years follow-up. The average active/passive range of motion was 54/55 degrees at the DIP joint, 96/98 degrees at the PIP joint, and 83/83 degrees at the MP joint. Twelve out of 16 flaps (75%) had two-point discrimination better than 10 mm. Moderate and severe problems included cold intolerance (six patients), hypersensitivity (three patients), stiffness (three patients), and numbness (two patients). Out of the 16 patients treated with this technique, 14 were satisfied with their surgical outcome. In experienced hands, this technique is a safe and reliable method with which to reconstruct volar-oblique fingertip amputations.