Surgical technique

The patient should be positioned such that both hand and foot dissections can be done simultaneously by two operative teams. Both dissections should be performed under tourniquet control with x4.5 loupe magnification. At least two people are necessary in each field to dissect the hand and foot, preferably with a scrub nurse for each team. The ideal operating room should have four overhead lights, two for each area of dissection. Generally the entire toe dissection can be done under one tourniquet time (Figs. 1 and 2).

The dissection of the great toe begins with preoperative markings of the superficial venous system over the foot and great toe. Once the foot is prepped and the tourniquet is elevated, a V-shaped incision is made from the middle of the first web space to a point over the extensor tendon at the level of the metatarsophalangeal joint (Fig. 3).

From this point, the incision is extended proximally in a straight line up the dorsum of the foot so that the venous dissection can be performed without difficulty and the medial flap can also be elevated to identify the dorsal arterial system. Dissection is performed down through the subcutaneous tissue to identify the major venous drainage of the great toe. The surgeon should find

Fig. 1. Lateral view of vascular anatomy of the great toe. (From Buncke HJ. Microsurgery: transplantation-replantation. Philadelphia: Lea & Febiger, 1991; with permission.)

the major tributaries flowing from the V-shaped incision and follow these back to a single outflow vein. This vein should then be dissected back proximally to at least the dorsum of the foot. If a vein graft is required, more proximal dissection may be necessary.

The next structures to identify will be the first dorsal metatarsal artery, extensor tendon, and the deep peroneal nerve. In the situation where the

Fig. 2. Dorsal view of vascular anatomy of the great toe. (From Buncke HJ. Microsurgery: transplantation-replantation. Philadelphia: Lea & Febiger, 1991; with permission.)

Fig. 3. Dissection of the dorsum of the foot. (From Buncke HJ. Microsurgery: transplantation-replantation. Philadelphia: Lea & Febiger, 1991; with permission.)

Fig. 2. Dorsal view of vascular anatomy of the great toe. (From Buncke HJ. Microsurgery: transplantation-replantation. Philadelphia: Lea & Febiger, 1991; with permission.)

Fig. 3. Dissection of the dorsum of the foot. (From Buncke HJ. Microsurgery: transplantation-replantation. Philadelphia: Lea & Febiger, 1991; with permission.)

patient has a very superficial first dorsal meta-tarsal artery, the surgeon should be able to find the artery in the middle of the first web space and dissect it distally and proximally. The deep peroneal nerve will be adjacent to the artery and should be harvested for repair to a dorsal sensory branch of the radial nerve later.

If the patient does not have a superficial first dorsal metatarsal artery, then it is easier to proceed to the first web space and begin the dissection by making a plantar V-shaped incision corresponding to the incision on the dorsal surface. The dissection should identify the lateral digital nerve to the great toe; just dorsal to this will be the lateral plantar digital artery to the great toe. The surgeon should then trace the lateral plantar digital artery to the great toe proximally into the first web space to the bifurcation of the lateral plantar digital artery of the great toe and medial plantar digital artery to the second toe. At this juncture there will be an H-shaped connection between the dorsal and plantar systems. The surgeon should be able to determine which is larger, the plantar system or the dorsal system, but often both are the same caliber. The surgeon should dissect out both systems and ultimately have dissected at least 3 to 4 cm of plantar artery and a section of the dorsal system dissected back to the take-off from the dorsalis pedis. All the side branches should be ligated and ultimately the branch to the second toe should also be ligated. There is a great deal of variability of the blood supply in this region, and care must be taken to define the vascular anatomy. Dissection of the lateral plantar digital nerve should proceed prox-imally. The surgeon can do an interfascicular dissection under loupe magnification, splinting the branch from the common digital nerve to obtain longer length of the lateral plantar digital nerve (Figs. 4 and 5).

Dissection is then performed along the plantar surface of the foot, elevating a thin skin and subcutaneous flap of the plantar surface of the toe to avoid a bulbous skin pad just proximal to the metatarsophalangeal crease at the thumb. The flexor tendon sheath is opened at the level of the metatarsophalangeal joint and the flexor tendon is dissected proximally to obtain adequate length.

Attention is then turned to the medial aspect of the great toe, identifying the medial plantar digital nerve and dissecting this proximally. At this time, the surgical team working on the hand should be able to define the length of artery, vein, nerve, flexor, and extensor tendon necessary to perform primary repairs. With this information, the surgeons at the foot can then cut the flexor tendon, reflect it distally, and begin incising along the volar aspect of the joint capsule, leaving the sesamoid bones with the metatarsal on the foot to act as a good weight-bearing surface for the patient in the future. The metatarsophalangeal joint capsule is then incised circumferentially, making sure not to inadvertently damage the extensor tendon, which is very adherent to the dorsal capsule. Obviously care is taken not to damage the vascular pedicles. Digital nerves are then ligated at the appropriate length. The surgeon should make sure that the digital nerves are cut so that the neuromas that form in the foot are proximal to the walking surface of the foot at the metatarsal head.

The great toe is still attached to the foot by the extensor tendon, which acts as a protective leash to avoid avulsion of the vascular pedicles. Before releasing the tourniquet, a microvascular clamp is placed on either the plantar or dorsal system. The tourniquet is released and the toe will hopefully pink up immediately; frequently however, to the surgical team's dismay, the toe will

Fig. 4. Dissection of first interspace. (From Buncke HJ. Microsurgery: transplantation-replantation. Philadelphia: Lea & Febiger, 1991; with permission.)
Fig. 5. Clinical dissection of first interspace.

take several minutes to pink up. Liberal use of warm saline irrigation over the toe and papavarin is helpful in reversing spasm. Care should be taken to explore the artery and tie or clip off unsatisfied side branches causing segmental vasospasm. Once the toe is pink with normal capillary refill, the artery and vein are clamped proximally and ligated. The extensor tendon is then divided and the toe is now free to be transplanted to the hand.

Care should be taken to get strict hemostasis of the foot donor site. The foot should be closed over a suction drain. We will often remove the dorsal two thirds of the metatarsal head, leaving the plantar surface and sesamoids intact. We then advance the sesamoids and attach them to the weight-bearing surface of the metatarsal head to get adequate padding over the plantar surface of the metatarsal head by the sesamoids holding them in position with a through-and-through stitch through the metatarsal head and through the sesamoids. The skin is then closed in layers. As a general rule, it is better to leave more skin on the foot side than on the transplanted toe to prevent donor site wound complications. A posterior splint is placed for immobilization for approximately 1 week. Weight bearing occurs at 3 weeks and advanced to fully ambulating over the next few weeks.

Once the toe is transplanted to the hand operative area, preparations are made for osteo-synthesis. We have used several types of osteosyn-thesis for toe transplantation. The ideal situation is where there is a segment of proximal phalanx left on the thumb that can be used as a peg inserted inside the medullary cavity of the proximal phalanx of the toe. In this situation, the surgeon releases the capsular structures around the proximal phalanx of the toe and uses an oscillating saw to remove the proximal 2 to 3 mm of proximal phalanx, including the articular surface. A high-speed burr can then be used to shape the inside of the proximal phalanx medullary canal to fit the proximal phalanx of the thumb so that they fit together snugly with an overlap of at least 3 to 4 mm. Using a self-tapping screw system four cortices can be secured across the osteosynthesis site and confirmed with intraoperative fluoroscopy. This provides very stable, rigid fixation and the patient can begin movement almost immediately after surgery (Fig. 6). Otherwise, longitudinal or crossed K-wires or plates and screws can be used.

If there is inadequate bone length on the proximal phalanx of the thumb, then a decision must be made by the surgeon whether to use longitudinal K-wires for osteosynthesis, or whether to reconstruct a new MCPJ using the metacarpal head of the thumb and the articular surface of the proximal phalanx of the toe. This neo-joint is surprisingly congruous and is often as good as trying to perform osteosynthesis to a minimal remnant of the proximal phalanx of the thumb. If the decision is to make a neo-joint, then at least four to five strong braided, non-absorbent sutures are placed in both collateral ligaments, volar plate, and dorsal capsule. A K-wire is placed across the joint for 2 to 3 weeks postoperatively to help protect the capsular and ligament repairs.

Once the osteosynthesis or neo-MCPJ has been created, the extensor tendon is then repaired. Usually there is adequate length to perform

Fig. 6. Four cortical screw rigid fixation of thumb proximal phalanx to proximal phalanx of great toe for early active motion.

Fig. 6. Four cortical screw rigid fixation of thumb proximal phalanx to proximal phalanx of great toe for early active motion.

Fig. 7. IP joint motion in great toe transplants is often better than IP joint motion in crushed or avulsed replanted thumbs.

a Pulvertaft weave of the long extensor of the toe to the extensor system of the thumb.

Attention is then turned to the volar aspect of the toe transplant where flexor tendon repair is performed, generally as far proximally as possible to avoid tendon adhesions at the level of the A1 pulley, which we usually release. We use a four-strand repair with an epitendonous suture. With these tendon repairs and four cortices osteosyn-thesis, we can begin active motion almost immediately after surgery, to hopefully prevent tendon adhesions and capsular scarring at the MCPJ.

The operating microscope is then brought into the operative field and an end-to-end or end-toside anastomosis of the first dorsal metatarsal artery to the dorsal radial artery is performed. If the plantar system is used, then the medial plantar digital artery of the great toe is anastomosed to the ulnar digital artery of the thumb, or it can be extended proximally with a vein graft to the dorsal radial artery for an end-to-end or end-to-side anastomosis. The vein is then anastomosed end-to-end to the cephalic vein. There should be good flow through the anastomoses and the toe should have normal capillary refill.

The hand is turned over and both digital nerves are then repaired. Sometimes we will repair the nerves after repairing the flexor tendon, but before repairing the artery and vein if ischemia time allows for this. Much of the initial repair of the transplanted toe can be performed under tourniquet control.

The skin is then closed loosely. Skin grafts are used liberally. Split thickness skin grafts are often placed directly over pedicles, vein grafts, and vascular anastomoses without major complications. The hand is placed immobilized in a thumb spica splint at the end of the operation.

Postoperative management

Our postoperative regimen includes low molecular weight dextran, which is started immediately after arterial repair and aspirin 325 mg daily. Heparin is used only in take-back situations or in the case of an intraoperative vascular thrombotic event. The patient is usually kept in the hospital for 5 to 7 days, spending the first 48 hours in the ICU for close monitoring. The patient is not allowed to

Table 1

Summary of functional results

Table 1

Summary of functional results

Sensory recovery—2-point

8 mm (mean)

discrimination

Sensory recovery—

5 mm (mean)

Protective sensation

MCPJ ROM

44 degrees

(63% of normal side)

IPJ ROM

40 degrees

(59% of normal side)

Grip strength

77% of normal side

Pinch strength

67% of normal side

Abbreviations: MCPJ, metacarpophalangeal joint; ROM, range of motion; IPJ, interphalangeal joint.

Abbreviations: MCPJ, metacarpophalangeal joint; ROM, range of motion; IPJ, interphalangeal joint.

Fig. 8. Great toe transplants over time often look more like thumbs than great toes. The left thumb is the uninjured thumb, the middle digit is the left great toe, and the right digit is the right great toe transplant to the right thumb. The right thumb looks more like a thumb than a toe.

place the foot in a dependent position for at least 2 to 3 weeks. Patients rarely require any orthotic device for the donor foot following this surgery.

Postoperative monitoring

Clinical assessment by experienced nurses remains our standard for monitoring free tissue transplants. Particular vigilance in the early postoperative period (48 hours) will lead to early salvage in the event of vascular compromise. If detected within a 6-hour window, salvage rates of more than 90% can be expected.

We have used multiple techniques to monitor our microvascular transplants: fluorescein dye has been used in our microsurgical unit since the early 1980s. The three-fold rise and fall to baseline is similar to our digital replantation protocol for detection of arterial inflow and venous outflow problems. We have used the implantable venous

Fig. 9. (A-G) Great toe and rectus abdominis simultaneous transplant. This 7-year-old right-handed boy lost his fingers and thumb in a commercial meat grinder. He needed an opposing digit and soft tissue to create a web space. In one operation, a great toe and rectus abdominis muscle were transplanted. (H) Postoperative function 1 year after transplantation.

Fig. 9. (A-G) Great toe and rectus abdominis simultaneous transplant. This 7-year-old right-handed boy lost his fingers and thumb in a commercial meat grinder. He needed an opposing digit and soft tissue to create a web space. In one operation, a great toe and rectus abdominis muscle were transplanted. (H) Postoperative function 1 year after transplantation.

Fig. 10. (A-G) Great toe, second toes, and fourth toes transplanted for thumb and finger reconstruction. This 35-year-old right-handed man lost all four fingers and thumb in a roller crush avulsion injury. He had marginal skin and soft tissue cover for his hand with a pedicle groin flap and STSG. With expansion of the dorsal skin of his hand, we were able to create a first web space and transplant the great toe. Four months later, he underwent double second toe transplantation to reconstruct the ring and small fingers. Four months later, he underwent double fourth toe transplantation to reconstruct the index and middle fingers. (H) He has excellent pinch and grasp. This operation should only be performed for a very motivated, intelligent, well-informed patient.

Fig. 10. (A-G) Great toe, second toes, and fourth toes transplanted for thumb and finger reconstruction. This 35-year-old right-handed man lost all four fingers and thumb in a roller crush avulsion injury. He had marginal skin and soft tissue cover for his hand with a pedicle groin flap and STSG. With expansion of the dorsal skin of his hand, we were able to create a first web space and transplant the great toe. Four months later, he underwent double second toe transplantation to reconstruct the ring and small fingers. Four months later, he underwent double fourth toe transplantation to reconstruct the index and middle fingers. (H) He has excellent pinch and grasp. This operation should only be performed for a very motivated, intelligent, well-informed patient.

Doppler, a particular advantage in the intraoperative period during flap insetting (detection of venous compromise with flap pedicle compression). Most recently, the Bowman thermodilution (Hemedex) probe and Vioptix (tissue oxygen saturation) probe are in the early phases of testing of their clinical utility.

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