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Microsurgery in Orthopedics
Symposium on Orthopedic Surgery
Microsurgery in Orthopedics
Leonard F. Hubbard, M.D.,* and james H. Herndon, M.D.t
Microsurgery has its foundations in otolaryngology and neurosurgery. Magnification and operating microscopes have been used in these fields for years to perform a variety of operations. In replantation surgery, in free tissue transfer, and in other microsurgical procedures, extensive preliminary work was done by the Chinese as well as by the Americans, and a group of American surgeons traveled to China to see firsthand what had been accomplished. 28 As a result of this investigation, many ideas and innovations from that country were exported to the United States and were applied to hand surgery, orthopedics, and plastic surgery. Since the techniques of microsurgery are employed by many specialties, including hand surgery, orthopedics, plastic surgery, urology, gynecology, and general surgery, many institutions sponsor workshops for the teaching of these techniques. It rapidly became apparent that the place to acquire skills for microsurgery was in the laboratory. The femoral artery of the Sprague-Dawley white rat closely approximates the size of the human digital vessel, 1 mm in outside diameter, and is an excellent and inexpensive model. After skills are acquired in the laboratory, they can be maintained either through clinical practice or in the laboratory. The average surgeon needs 30 to 50 hours of work in the laboratory before these skills can be competently applied in the clinical setting. Workshops and laboratory courses are now widely available across the country. Today's operating microscopes are expensive, costing $12,000 to $25,000 and more, depending on the features. Microscopes for clinical use in hand surgery generally have a double head, with eye pieces situated at 180 degrees. This design enables the surgeon and his assistant to work together in the same field. The more expensive operating microscopes have foot controls, so that the surgeon is not required to look away from the *Assistant Professor, Department of Orthopaedics, Rhode Island Hospital, Brown University, Providence, Rhode Island tProfessor and Chairman, Department of Orthopaedics, Rhode Island Hospital, Brown University, Providence, Rhode Island
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microscope to make adjustments in focus, magnification power, or field position. Smaller and less expensive microscopes, some with single heads, are also satisfactory for laboratory work. The operative techniques required of the surgeon during microsurgical procedure require precise attention to detail. Instruments must be in excellent condition, operating microscopes must be appropriately maintained, and operating room personnel must be cognizant of the difficulties under which the surgeon must work. Fortunately, attention has been paid to the necessity for maintaining the surgeon's peace of mind, and breaks during the operative procedure and other appropriate conditions are recognized universally as necessary for successful microsurgery. REPLANTATION
In 1963, the Chinese reported a large series of replantation of severed digits in 162 patients. 29 Malt introduced clinical replantation to the United States, reporting his experience with severed arms. 21 • 28 Based on this early experience and with the laboratory data generated by Buncke, Kleinert, and others, replantation has become a procedure commonly performed in many major institutions and has undergone considerable evolution. A high degree of survival of replanted digits, up to 90 per cent, is achieved by experienced surgeons, particularly since the details of patient selection and operative technique have become better understood. 17• 30• 35• 38 Not every amputation is an indication for replantation. Careful consideration must be given by the surgeon to the expected functional result, particularly whether the replanted digit will be in the way or will contribute significantly to hand function. The best situation for replantation is a guillotine amputation in which there is minimal damage to bone, tendons, and neurovascular structures. In the hand, the enormous damage done by amputation often leads to a suboptimal functional result. Single digits are generally not replanted in adults, since the functional result obtained too frequently leaves the patient with an abnormal digit that detracts from overall hand function. Multiple digits are usually replanted, recognizing that the functional result obtained, though less than optimal, is better than multiple amputation stumps. Amputations distal to the proximal interphalangeal joint and proximal to the metacarpophalangeal joints appear to do best in terms of motion, although all zone II injuries have limitations to recovery. Amputations through the proximal segment are highly prone to stiffness due to the complexity of the flexor and extensor mechanisms in this area. Multiple procedures, including tenolysis and two-stage tendon grafting, may be required after the amputation to provide useful function. 17• 38 The recovery of sensibility is often impaired, even in the presence of technically good nerve repairs. Thumbs are nearly always replanted, since no thumb reconstruction is as good as the patient's own thumb. Chow has reported a survival rate in replanted thumbs of 82 per cent, approximately that of other digits. Two-point discrimination of 5 mm was often achieved in these cases. 6
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These judgments are less clear in children, since the functional results of single replanted digits in children may be quite good, certainly much better than that in adults. Growth has been observed to occur after replantation of digits in children. In general, lower limbs are not replanted in adults, except for the occasional amputation through the thigh in which replantation may be considered to save the knee joint or for other salvage procedures. 15 Modern prosthetics allow for excellent ambulation and function with amputations below the knee; replantations usually leave the patient with a stiff, painful, and atrophic lower limb with abnormal sensation. This may, however, be subject to review, since some surgeons report better success recently with newer techniques. 18 For replantation, the patient must be in good health, since the operations are frequently prolonged (as much as 18 hours), and the patient must be able to tolerate the anesthesia. The patient's occupation must be considered as well as his desire for replantation. The thoughtful surgeon, however, will not allow the patient's enthusiasm for replantation in the acute care setting to overwhelm his good judgment and predictions about the patient's functional result and long-term satisfaction with the procedure. Patients who smoke, who have peripheral vascular disease, or who have diabetes are poor candidates for replantation. 17• 30 Preoperative care of the patient with an amputation is extremely important. The patient's hand should be dressed and elevated to minimize swelling, and the amputated part should be placed in a plastic bag, which is subsequently placed on ice. The limb should not be immersed in any solution, and in general perfusion is not advisable. Perfusion of a whole limb might be considered only when lengthy transport is required, or when some delay will be encountered in revascularization, particularly if muscle is involved. This approach, however, is still controversial. The patient should be transported as soon as possible to a facility in which replantations are performed. In the best circumstances, several surgeons will be available for these replantations so that the efficiency of the operating team can be maximized. Early notification of the operating room makes it possible to assemble the special instruments and to set aside time for these procedures. Preoperative antibiotics are administered, usually a cephalosporin. We use dextran 40 (Rheomacrodex) at 25 ml per hour for five days, and aspirin 10 gr, b.i.d., for three weeks. These agents are thought to help prevent adhesion of platelets, the first step in thrombosis at a microsurgical anastomosis. During the surgical procedure, the amputated part and proximal limb are explored simultaneously if possible. Structures are individually identified and tagged, including nerves, arteries, veins, and tendons. When all structures on both sides have been identified, bony stabilization is carried out. 12 The method of stabilization varies, but usually involves Kirschner wire fixation or interosseous wiring, as described by Lister. 19 Tendons are then repaired using the standard Kessler suture. The arteries are anastomosed, using the operating microscope and no. 10-0 s,uture material as appropriate. We prefer not to allow perfusion of the amputated part until
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at least one vein has been anastomosed, so that stasis at the arterial anastomosis is prevented. Aggressive debridement of vessels is mandatory, and usually vein grafts (taken from the forearm) must then be interposed to prevent tension on the vessel repair. Once flow has been reestablished, with two veins preferably anastomosed for each artery done, the nerves are repaired. Revascularization of digits can be carried out up to 12 hours of cold ischemia, although it is certainly preferable fo minimize the time the digits are ischemic. Skin grafts can successfully be applied directly over arteries, vein grafts, and nerves and are often necessary to close wounds because of the swelling. 20 Postoperatively, the patient's hand is maintained in an elevated position, since venous obstruction is the most common problem. Treatment with aspirin, 10 gr, b.i.d., is continued for three weeks postoperatively and with dextran 40 for five days. Antibiotic therapy is discontinued after 48 to 72 hours, depending on the contamination of the wound. If the bone fixation technique used allows motion, we prefer a controlled, passive immobilization program, beginning at five days, to promote flexor tendon gliding. Postoperative monitoring is extremely important. The room is kept warm (80 to 85F), since core temperature appears to correlate with vasospasm. Color, capillary refill, and fullness of the pulp are monitored hourly for the first 24 hours. Monitoring of skin temperature, using a standard operating room temperature monitor with the skin probe, is also performed hourly. Reoperation has become less frequent as the criteria for patient selection have become better defined, and as operative technique has improved (Fig. 1). REPAIRS OF NERVES AND VESSELS
The operating microscope has now become an integral part of the method of any surgeon repairing peripheral nerves, since it allows for much more accurate anatomic alignment. There is no magic in these techniques; rather, the ability to assess more accurately the fascicular size, to orient the fascicles, and to use finer suture materials has proved to be an advantage. The nerve repair favored by most surgeons today is the so-called "group fascicular repair." In this technique, bundles of fascicles are identified, approximated, and sutured using no. 9-0 and no. 10-0 suture materials. Although this technique can be done with high-power loupes, it is done much more easily with the operating microscope. Investigations of fascicular repairs in which individual fascicles are sutured with microsutures have not shown this to be a better technique, presumably since the additional suture material induces scarring. 34• 41 The group fascicle repair appears to allow for better mechanical orientation, and this basic repair is then supplemented by epineural sutures placed around the periphery of the nerve. The nerves are sutured under as little tension as possible, and nerve grafts are employed where necessary. Without the microscope, much of the recent work on the brachial plexus would be impossible. Although it is currently impossible to repair the root avulsion injury, work by Millesi
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Figure l. A, An 18-year-old man with transmetacarpal amputation of dominant hand by a radial arm saw. B, Amputation specimen. C, Multiple vein grafts from the forearm sutured with no. 10-0 nylon (21 j.Lm). D, Final result at nine months. Protective sensation present. Patient returned to occupation of farmer.
and others has shown the practicality of brachial plexus grafting with cable grafts and the usefulness of selected epineurolysis. 25 In addition to replantation, there are often other situations in which vessel repairs in the hand are necessary. Ulnar artery thrombosis may be treated either by excision of the ulnar artery or by an interposition vein graft. Lacerations of the superficial arch of the hand, the radial or ulnar artery, or the digital vessels are common injuries, and repair of these structures is often indicated. Unfortunately, repair of an isolated radial artery or ulnar artery is often only temporarily successful; only about 50 per cent of these repairs stay open permanently. This probably relates to complex flow patterns in the hand, with subsequent stasis at the suture line. However, with the common use of the radial artery for monitoring blood gases and arterial pressures during major surgical procedures, illnesses, or injuries, it would appear to be prudent to repair these arterial injuries when they are encountered. If the patient has an isolated laceration of the ulnar artery that is not repaired, and the radial artery on that hand is catheterized at a later date, the viability of the hand may be in danger.
TRANSFER OF FREE TISSUE A common problem in orthopedics is tissue loss as a result of injury, tumor, or other disorder and may involve skin, skin and subcutaneous
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tissue, or bone loss. Both skin and bone loss were originally treated with free grafts, using split-thickness grafts, pedicle flaps, and free avascular bone grafts. ·However, each of these has its problems, and the advent of microsurgery allowed for the development of new techniques to deal with these problems.
FREE FLAPS Large blocks of skin and subcutaneous tissue may be vascularized either randomly or axially, with a single primary axial vascular supply. Random flaps have classically been transferred as pedicle flaps, waiting until a new blood supply is established for the recipient site before the donor pedicle can be divided. Axial flaps have been transferred much the same way, although these flaps can have a longer length-to-base ratio because of the greater relative blood supply and longitudinal orientation. However, pedicles limit the transfer of these tissues to local areas within the swing of the pedicle or require complex techniques in which the pedicle is transferred on carriers such as the forearm. Transferring tissue in one stage with immediate revascularization at the recipient site obviates these difficulties. The first free flap to be performed was the groin flap. 7 • 13 This axial pattern flap, based on the superficial circumflex iliac artery, has been transferred to multiple locations to provide skin cover over serious wounds. Unfortunately, however, the groin flap has not been as reliable as was hoped, since there is considerable variation in the anatomy of the superficial circumflex iliac artery. 16 Other flaps that have been transferred include the dorsalis pedis flap (based on the dorsalis pedis artery, it may be innervated by the deep peroneal nerve), 24 the forearm flap (based on the radial artery), 26 the saphenous flap (saphenous artery), 2 and the recently described scapular flap. 10 Each of these flaps has had applications, but the latissimus dorsi remains the current model for reliability and versatility. 3 · 11 This can be transferred either as a myocutaneous flap, together with the overlying skin, or as muscle only, which is skin grafted, and which can be of considerable size. The latissimus dorsi muscle is supplied by the thoracodorsal artery, a branch of the subscapular artery. It has a single, anatomically constant, well-defined pedicle that enters the muscle near its proximal insertion. Even if skin over the muscle is taken, the donor site can generally be closed primarily. Loss of this muscle appears to cause no significant defect in the patient's strength or shoulder motion. The artery is large (1.5 to 2.0 mm), is constantly accompanied by one or two similar-sized veins, and may be innervated by repairing the accompanying thoracodorsal nerve to a motor nerve in the recipient area. A pedicle of 5 to 8 em can easily be dissected by ligating the constant branch to the serratus anterior. Coverage of large defects can be efficiently accomplished using these free flap techniques. Although many defects over the tibia, for instance, can be covered with the local gastrocnemius or soleus pedicle myocutaneous flap, the distal tibia is often impossible to reach. This orthopedic injury is
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Figure 2. A, 15,000 volt electrical exit wound in the left knee of a 15-year-old boy. Interior of knee joint exposed. B, Latissimus dorsi muscle transferred in one stage after debridement. Thoracodorsal artery anastomosed to anterior tibial artery. Surface covered with meshed split-thickness skin graft. C, Stable coverage six weeks postoperatively. D, 110° knee flexion present. Patient returned to skiing without knee problems.
common, associated with high-energy, class III tibial fractures. Free flaps do not require awkward immobilization or the application of casts or other external fixation devices, as for cross-leg flaps, but they are not without complication. The latissimus dorsi flap has considerably increased the success rate of free flaps, and generally are 80 per cent or more successful (Fig. 2). Occasional revisions of anastomoses or thrombectomies are necessary. Where possible, arterial inflows of as high a pressure as possible are desirable, and vein grafts may be required to reach high-pressure inflow. In orthopedics, wounds are the most common reason for employing these flaps. However, considerable interest has developed recently in the use of the latissimus dorsi flap, with accompanying muscle, for the treatment of subacute and chronic osteomyelitis in difficult situations. Radical debridement of infected bone and coverage with these flaps if necessary bring in a substantial new blood supply and appear to be beneficial in obtaining control over these difficult infections. Free flaps may also be employed to cover open joints and on occasion may provide sensible skin in the hand. The first web space flap, which is based on the first dorsal metatarsal artery (continuation of the dorsalis pedis artery) has proved most useful. This flap is innervated by the deep peroneal nerve, and very useful two-point
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discrimination can be achieved when this flap is innervated in its new location. 24 TOE TRANSFER
The transfer of digits, particularly the toe-to-thumb transfer for replacement of the thumb lost because of trauma or because of congenital malformation, has provided an innovative way of coping with loss or congenital absence of the digit. Standard methods of thumb reconstruction involve iliac bone grafts and pedicle grafting, followed by island flaps from an adjacent finger to provide some sensation. The transfer of a whole great toe or second toe, however, offers the opportunity for early establishment of properly oriented sensibility, for motion, and, in the case of the congenital malformation, for growth. These procedures are complex but have been reasonably reliable in the hands of those experienced in microvascular techniques. 4• 39• 40 VASCULARIZED BONE GRAFTS
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Bone grafts are widely used in orthopedic surgery, in such operations as arthrodesis of joints, treatment of fracture non unions, and reconstruction of bone loss after trauma or surgery. The standard bone graft in which cortical or cancellous bone is taken from a donor site and transplanted to a recipient site depends on the graft acting as a scaffold. Over a long period of time, the graft is incorporated into new bone and replaced. There is a relatively low survival of the bone cells in this setting, since they must depend on deriving their nutrition by diffusion from the surrounding tissue. When a tubular bone such as a fibula is used to reconstruct a segment of missing bone, the graft must be replaced from the ends by the process known as "creeping substitution." Although the ends of the bone may heal, this avascular bone graft is replaced by a process of resorption and new bone formation. In general, the resorption proceeds more rapidly than new bone formation, and the large resorption cavities formed may mechanically weaken the bone and result in fracture, particularly at six to nine months. As long as two years is required for complete replacement of a graft of this type. Although avascular cancellous grafts are incorporated more rapidly because of the larger surface area, they offer little structural strength and act in large part as stimulations to new bone growth. Some of these problems were alleviated when the vascularized bone graft was conceived. In this technique, a bone is transplanted, together with the blood vessels that supply it. With the anastomosis of these vessels to those locally in the recipient area, the bone has an immediate new blood supply. The process of replacement is therefore eliminated, and, theoretically at least, the bone should heal by the standard process of fracture healing at the two ends. By the use of this technique, many large segmental defects can now be approached with greater certainty. Although there was concern initially that the bone cells (osteocytes) would not survive the
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Figure 3. A. A 35-year-old man with saw injury to left forearm, transecting ulnar artery and nerve. Segmental defect in ulna. B, Preoperative arteriogram, with arrow on transected ulnar artery. External fixation in place. C, Vascularized fibula harvested with surrounding muscle cuff, on the peroneal artery and vein (under probe). D, Postoperative arteriogram, showing fibula in place with peroneal artery patent. Arrow indicates anastomosis between peroneal artery and ulnar artery. (Case courtesy of Richard I. Burton, M.D., University of Rochester, Rochester, New York.)
ischemia and transplantation process, it has been shown that these cells are quite resistant and can survive 25 hours of ischemia under controlled experimental conditions. 5 Joints have also been transplanted and epiphyseal growth demonstrated. 23 The fibula is the most commonly used free vascularized bone graft, as described by Weiland and others. 9• 31 • 36 • 37 The fibula is supplied by a single intramedullary nutrient artery and a periosteal blood supply that approaches the bone through the surrounding muscle cuff. The fibula is harvested through a posterolateral incision, and the peroneal artery is isolated. The fibula is then dissected free, leaving a surrounding 0.5 to 1 em muscle cuff to protect the periosteal blood supply. After the fibula has been divided at both ends, flow of blood from the medullary cavity can be demonstrated. The vessels are then divided, the fibula is transplanted to its new location, and the vessels anastomosed. This technique is useful for such problems as congenital pseudarthrosis of the tibia, segmental defects in the tibia or femur, and reconstruction of the bones of the upper extremity after resection for tumor or trauma. Standard orthopedic techniques are used in fixing the bone at both ends (Fig. 3). In some instances, such as in facial reconstruction, a more slender and less bulky bone is required, and for this, the rib is the most appropriate. The blood supply of the rib is derived from two major sources. The first is the posterior artery, which supplies a nutrient vessel to the center of the bone. The second is from the more anterior intercostal artery, which supplies the exterior of the bone through a periosteal cuff. Most surgeons use the anterior vessel, since dissection of the posterior intercostal artery is far posterior near the spine. Experimentally, the inclusion of both vessels
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Figure 4. A, Osteomyelitis and poor skin coverage of right medial malleolus three years after electrical injury. B, Radical debridement of soft tissue and bone, leaving 8 X 10 em defect. C, Latissimus dorsi free Hap with split-thickness skin grafts. Stable skin coverage provided, with new highly vascular tissue adjacent to bone. No further drainage. Flap will shrink by at least 40 per cent over first three months because of denervation.
does not appear to influence the healing of these grafts. 14 The rib is particularly suitable for reconstruction of defects in the mandible and can be molded to the curves required. Much attention has been given to composite grafts in which bone is included with soft tissue. The groin flap based on the superficial circumflex iliac artery can be taken together with a piece of underlying ilium, but this dissection is complicated by variations in anatomy. 1 Taylor has described composite bone grafts taken on the deep circumflex iliac artery, in which the anatomy is much more constant, the vessels are larger, and the blood supply to the bone more reliable. 32 • 33 However, many surgeons now depend on vascularized soft tissue coverage of segmental bone defects, such as seen in the tibia, with free flaps or local myocutaneous flaps. Underlying bone defects of 6 em or less are then reconstructed using cancellous bone from the pelvis. Defects of larger size are reconstructed with blocks of corticocancellous bone from the ilium, and very large defects are treated with vascularized fibular grafts (Fig. 4).
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CONCLUSION In orthopedics, as in many other specialties, the advent of microsurgical procedures has encouraged innovative solutions to difficult problems. Replantation was the first clinical success and was rapidly followed by the development of other procedures, such as free tissue transfers. As these techniques become more refined, there will undoubtedly be many more applications. REFERENCES 1. Acland, R. D.: The free iliac Hap. Plast. Reconstr. Surg., 64:30, 1979. 2. Acland, R. D., Schustennann, M., Gadira, M., et al.: The saphenous neurovascular free Hap. Plast. Reconstr. Surg., 67:763-774, 1981. q. Bostwick, J., Nahai, F., Wallace, J. E., et al.: Sixty latissimus dorsi Haps, Plast. Reconstr. Surg., 63:31, 1979. 4. Buncke, H. J., and Shah, K.: Toe-digital transfers. In Serafin, D., and Buncke, H. J. (eds.): Microsurgical Composite Tissue Transfer. St. Louis, C. V. Mosby, 1979, pp. 573-586. 5. Berggren, A., Weiland, A. J., and Dorfinann, H.: The effect of prolonged ischemia time on osteocyte and osteoblast survival in composite bone grafts revascularized by microsurgical anastomoses. Plast. Reconstr. Surg., 65:290, 1982. 6. Chow, J. A., Bilos, Z. J., and Chunpropah, B.: Thirty thumb replantations: Indications and results. Plast. Reconstr. Surg., 65:626-630, 1979. 7. David, R. K., and Taylor, G. 1.: Distant transfer of an island Hap by microvascular anastomoses: A clinical technique. Plast. Reconstr. Surg., 52:111-117, 1973. 8. Ger, R.: Muscle transposition for treatment and prevention of chronic post-traumatic osteomyelitis of the tibia. J. Bone Joint Surg., 59A:784, 1977. 9. Gilbert, A.: Vascularized transfer of the fibular shaft. Int. J. Microsurg., 1:100-102, 1978. 10. Gilbert, A., and Teot, L.: The free scapular Hap. Plast. Reconstr. Surg., 69:601, 1982. 11. Gordon, L., Buncke, H. J., and Alpert, B. S.: Free latissimus dorsi Haps with splitthickness skin graft cover. A report of 16 cases. Plast. Reconstr. Surg., 70:173, 1982. 12. Hayes, M. G., and Urbaniak, J. R.: Management of bone in replantation surgery. AAOS Symposium on Microsurgery. Practical Use in Orthopaedics. St. Louis, C. V. Mosby, 1979, p. 96. 13. Harii, K., Ohmori, K., Torii, S., et al.: Free groin skin Haps. Br. J. Plast. Surg., 28:225237, 1975. 14. Hadel, R. M., Hatlurn, R. S., Rodrigo, J., et al.: The functional vascular anatomy of rib. Plast. Reconstr. Surg., 70:578-585, 1982. 15. Jupiter, J. B., Tsai, T. M., and Kleinert, H. E.: Salvage replantations-of lower limb amputations. Plast. Reconstr. Surg., 69:1-8, 1982. 16. Katai, K., Kido, M., and Numaguchi, Y.: Angiography of the iliofemoral arterio-venous system supplying free groin Haps and free hypogastric Haps. Plast. Reconstr. Surg., 63:671-679, 1979. 17. Kleinert, H. E., Juhala, C. A., Tsai, T. M., et al.: Digital replantation-selection, techniques, and results. 0RTHOP. CLIN. NORTH. AM., 8:309-318, 1977. 18. Lesguoy, M. A.: Successful replantation of lower leg and foot, with good sensibility and function. Plast. Reconstr. Surg., 67:760--765, 1979. 19. Lister, G.: Interosseous wiring of the digital skeleton. J. Hand Surg., 3:427-435, 1978. 20. McDonald, H. D., Buncke, H. J., and Goodstein, W. A.: Split-thickness skin grafts in microvascular surgery. Plast. Reconstr. Surg., 68:731, 1981. 21. Malt, R. A., and McKahn, C.: Replantation of severed arms. ].A.M.A., 189:716, 1964. 22. Mathes, S. J., Alpert, B. S., and Chang, N.: Use of the muscle Hap in chronic osteomyelitis: Experimental and clinical correlation. Plast. Reconstr. Surg., 69:815, 1982. 23. Mathes, S. J., Buchanan, R., and Weeks, P. M.: Microvascular joint transplantation with epiphyseal growth. J. Hand Surg., 5:586, 1980.
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24. May, J. W., Chait, L.A., Cohen, B. E., et al.: Free vascularized Hap from the first web space of the foot in hand reconstruction. J. Hand Surg., 2:387-393, 1977. 25. Millesi, H.: Surgical management of brachial plexus injuries. J. Hand Surg., 2:367-379, Sept. 77. 26. Mulhauer, W., Herhdl, E., and Stock, W.: The forearm Hap. Plast. Reconstr. Surg., 70:336, 1982. 27. Ostrup, L. T., and Frederickson, J. M.: Distant transfer of a free living bone graft by microvascular anastomoses: An experimental study. Plast. Reconstr. Surg., 54:274, 1974. 28. Report of the American Replantation Mission to China. Plast. Reconstr. Surg., 52:476, 1973. 29. Sixth People's Hospital, Shanghai: Replantation of severed fingers: Clinical experience in 162 cases involving 270 severed fingers. July 1963. 30. Tarnai, S.: Digital replantation: Analysis of 163 replantations in an 11-year period. Clin. Plast. Surg., 5:195, 1978. 31. Taylor, G. 1., Miller, G. D. H., and Ham, F. J.: The free vascularized bone graft-a clinical extension of microvascular techniques. Plast. Reconstr. Surg., 55:533, 1975. 32. Taylor, G. I., Townsend, P., and Corbett, R.: Superiority of the deep circumflex iliac vessels as the supply for free groin Haps: Experimental work. Plast. Reconstr. Surg., 64:595-604, 1979. 33. Taylor, G. 1., Townsend, P., and Corbett, R.: Superiority of the deep circumflex iliac vessels as the supply for free groin Haps: Clinical work. Plast. Reconstr. Surg., 64:745759, 1979. 34. Tupper, J.: Fascicular nerve repairs. In Jewett, D. L. and McCarroll, H. R. (eds.): Nerve Repair and Regeneration, St. Louis, C. V. Mosby, 1980. 35. Urbaniak, J. R.: Replantation of amputated parts-techniques, results, and indications. AAOS Symposium on Microsurgery. Practical Use in Orthopaedics. St. Louis, C. V. Mosby, 1979. 36. Weiland, A. J., 'and Daniel, R. K.: Microvascular anastomoses for bone grafts in the treatment of massive defects in bone. J. Bone Joint Surg., 61A:98-104, 1979. 37. Weiland, A. J., Kleinert, H. E., Kutz, J. E., et al.: Free vascularized bone grafts in surgery of the upper extremity. J. Hand Surg., 4:129-144, 1979. 38. Weiland, A. J., Villareal-Rios, A., Kleinert, H. E., et al.: Replantation of digits and hands: Analysis of surgical techniques and functional results in 77 patients with 86 replantations. J. Hand Surg., 21:1-12, 1977. 39. Yang, D., and Gu, Y. : Thumb Reconstruction utilizing second toe transplantation by microvascular anastomosis: A report of 78 cases. Chin. Med. J., 92:295, 1979. 40. Yoshimura, M.: Toe-to-hand transfer. Plast. Reconstr. Surg., 66:74-83, 1980. 41. Young, L., Wray, P. C., and Weeks, P. M.: A randomized prospective comparison of fascicular and epineural digital nerve repairs. Plast. Reconstr. Surg., 68:1, 89-92, 1981. Department of Orthopaedics Rhode Island Hospital Brown University Providence, RI 02912
Microsurgery in Orthopedics
Leonard F. Hubbard, M.D.,* and james H. Herndon, M.D.t
Microsurgery has its foundations in otolaryngology and neurosurgery. Magnification and operating microscopes have been used in these fields for years to perform a variety of operations. In replantation surgery, in free tissue transfer, and in other microsurgical procedures, extensive preliminary work was done by the Chinese as well as by the Americans, and a group of American surgeons traveled to China to see firsthand what had been accomplished. 28 As a result of this investigation, many ideas and innovations from that country were exported to the United States and were applied to hand surgery, orthopedics, and plastic surgery. Since the techniques of microsurgery are employed by many specialties, including hand surgery, orthopedics, plastic surgery, urology, gynecology, and general surgery, many institutions sponsor workshops for the teaching of these techniques. It rapidly became apparent that the place to acquire skills for microsurgery was in the laboratory. The femoral artery of the Sprague-Dawley white rat closely approximates the size of the human digital vessel, 1 mm in outside diameter, and is an excellent and inexpensive model. After skills are acquired in the laboratory, they can be maintained either through clinical practice or in the laboratory. The average surgeon needs 30 to 50 hours of work in the laboratory before these skills can be competently applied in the clinical setting. Workshops and laboratory courses are now widely available across the country. Today's operating microscopes are expensive, costing $12,000 to $25,000 and more, depending on the features. Microscopes for clinical use in hand surgery generally have a double head, with eye pieces situated at 180 degrees. This design enables the surgeon and his assistant to work together in the same field. The more expensive operating microscopes have foot controls, so that the surgeon is not required to look away from the *Assistant Professor, Department of Orthopaedics, Rhode Island Hospital, Brown University, Providence, Rhode Island tProfessor and Chairman, Department of Orthopaedics, Rhode Island Hospital, Brown University, Providence, Rhode Island
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microscope to make adjustments in focus, magnification power, or field position. Smaller and less expensive microscopes, some with single heads, are also satisfactory for laboratory work. The operative techniques required of the surgeon during microsurgical procedure require precise attention to detail. Instruments must be in excellent condition, operating microscopes must be appropriately maintained, and operating room personnel must be cognizant of the difficulties under which the surgeon must work. Fortunately, attention has been paid to the necessity for maintaining the surgeon's peace of mind, and breaks during the operative procedure and other appropriate conditions are recognized universally as necessary for successful microsurgery. REPLANTATION
In 1963, the Chinese reported a large series of replantation of severed digits in 162 patients. 29 Malt introduced clinical replantation to the United States, reporting his experience with severed arms. 21 • 28 Based on this early experience and with the laboratory data generated by Buncke, Kleinert, and others, replantation has become a procedure commonly performed in many major institutions and has undergone considerable evolution. A high degree of survival of replanted digits, up to 90 per cent, is achieved by experienced surgeons, particularly since the details of patient selection and operative technique have become better understood. 17• 30• 35• 38 Not every amputation is an indication for replantation. Careful consideration must be given by the surgeon to the expected functional result, particularly whether the replanted digit will be in the way or will contribute significantly to hand function. The best situation for replantation is a guillotine amputation in which there is minimal damage to bone, tendons, and neurovascular structures. In the hand, the enormous damage done by amputation often leads to a suboptimal functional result. Single digits are generally not replanted in adults, since the functional result obtained too frequently leaves the patient with an abnormal digit that detracts from overall hand function. Multiple digits are usually replanted, recognizing that the functional result obtained, though less than optimal, is better than multiple amputation stumps. Amputations distal to the proximal interphalangeal joint and proximal to the metacarpophalangeal joints appear to do best in terms of motion, although all zone II injuries have limitations to recovery. Amputations through the proximal segment are highly prone to stiffness due to the complexity of the flexor and extensor mechanisms in this area. Multiple procedures, including tenolysis and two-stage tendon grafting, may be required after the amputation to provide useful function. 17• 38 The recovery of sensibility is often impaired, even in the presence of technically good nerve repairs. Thumbs are nearly always replanted, since no thumb reconstruction is as good as the patient's own thumb. Chow has reported a survival rate in replanted thumbs of 82 per cent, approximately that of other digits. Two-point discrimination of 5 mm was often achieved in these cases. 6
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These judgments are less clear in children, since the functional results of single replanted digits in children may be quite good, certainly much better than that in adults. Growth has been observed to occur after replantation of digits in children. In general, lower limbs are not replanted in adults, except for the occasional amputation through the thigh in which replantation may be considered to save the knee joint or for other salvage procedures. 15 Modern prosthetics allow for excellent ambulation and function with amputations below the knee; replantations usually leave the patient with a stiff, painful, and atrophic lower limb with abnormal sensation. This may, however, be subject to review, since some surgeons report better success recently with newer techniques. 18 For replantation, the patient must be in good health, since the operations are frequently prolonged (as much as 18 hours), and the patient must be able to tolerate the anesthesia. The patient's occupation must be considered as well as his desire for replantation. The thoughtful surgeon, however, will not allow the patient's enthusiasm for replantation in the acute care setting to overwhelm his good judgment and predictions about the patient's functional result and long-term satisfaction with the procedure. Patients who smoke, who have peripheral vascular disease, or who have diabetes are poor candidates for replantation. 17• 30 Preoperative care of the patient with an amputation is extremely important. The patient's hand should be dressed and elevated to minimize swelling, and the amputated part should be placed in a plastic bag, which is subsequently placed on ice. The limb should not be immersed in any solution, and in general perfusion is not advisable. Perfusion of a whole limb might be considered only when lengthy transport is required, or when some delay will be encountered in revascularization, particularly if muscle is involved. This approach, however, is still controversial. The patient should be transported as soon as possible to a facility in which replantations are performed. In the best circumstances, several surgeons will be available for these replantations so that the efficiency of the operating team can be maximized. Early notification of the operating room makes it possible to assemble the special instruments and to set aside time for these procedures. Preoperative antibiotics are administered, usually a cephalosporin. We use dextran 40 (Rheomacrodex) at 25 ml per hour for five days, and aspirin 10 gr, b.i.d., for three weeks. These agents are thought to help prevent adhesion of platelets, the first step in thrombosis at a microsurgical anastomosis. During the surgical procedure, the amputated part and proximal limb are explored simultaneously if possible. Structures are individually identified and tagged, including nerves, arteries, veins, and tendons. When all structures on both sides have been identified, bony stabilization is carried out. 12 The method of stabilization varies, but usually involves Kirschner wire fixation or interosseous wiring, as described by Lister. 19 Tendons are then repaired using the standard Kessler suture. The arteries are anastomosed, using the operating microscope and no. 10-0 s,uture material as appropriate. We prefer not to allow perfusion of the amputated part until
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at least one vein has been anastomosed, so that stasis at the arterial anastomosis is prevented. Aggressive debridement of vessels is mandatory, and usually vein grafts (taken from the forearm) must then be interposed to prevent tension on the vessel repair. Once flow has been reestablished, with two veins preferably anastomosed for each artery done, the nerves are repaired. Revascularization of digits can be carried out up to 12 hours of cold ischemia, although it is certainly preferable fo minimize the time the digits are ischemic. Skin grafts can successfully be applied directly over arteries, vein grafts, and nerves and are often necessary to close wounds because of the swelling. 20 Postoperatively, the patient's hand is maintained in an elevated position, since venous obstruction is the most common problem. Treatment with aspirin, 10 gr, b.i.d., is continued for three weeks postoperatively and with dextran 40 for five days. Antibiotic therapy is discontinued after 48 to 72 hours, depending on the contamination of the wound. If the bone fixation technique used allows motion, we prefer a controlled, passive immobilization program, beginning at five days, to promote flexor tendon gliding. Postoperative monitoring is extremely important. The room is kept warm (80 to 85F), since core temperature appears to correlate with vasospasm. Color, capillary refill, and fullness of the pulp are monitored hourly for the first 24 hours. Monitoring of skin temperature, using a standard operating room temperature monitor with the skin probe, is also performed hourly. Reoperation has become less frequent as the criteria for patient selection have become better defined, and as operative technique has improved (Fig. 1). REPAIRS OF NERVES AND VESSELS
The operating microscope has now become an integral part of the method of any surgeon repairing peripheral nerves, since it allows for much more accurate anatomic alignment. There is no magic in these techniques; rather, the ability to assess more accurately the fascicular size, to orient the fascicles, and to use finer suture materials has proved to be an advantage. The nerve repair favored by most surgeons today is the so-called "group fascicular repair." In this technique, bundles of fascicles are identified, approximated, and sutured using no. 9-0 and no. 10-0 suture materials. Although this technique can be done with high-power loupes, it is done much more easily with the operating microscope. Investigations of fascicular repairs in which individual fascicles are sutured with microsutures have not shown this to be a better technique, presumably since the additional suture material induces scarring. 34• 41 The group fascicle repair appears to allow for better mechanical orientation, and this basic repair is then supplemented by epineural sutures placed around the periphery of the nerve. The nerves are sutured under as little tension as possible, and nerve grafts are employed where necessary. Without the microscope, much of the recent work on the brachial plexus would be impossible. Although it is currently impossible to repair the root avulsion injury, work by Millesi
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Figure l. A, An 18-year-old man with transmetacarpal amputation of dominant hand by a radial arm saw. B, Amputation specimen. C, Multiple vein grafts from the forearm sutured with no. 10-0 nylon (21 j.Lm). D, Final result at nine months. Protective sensation present. Patient returned to occupation of farmer.
and others has shown the practicality of brachial plexus grafting with cable grafts and the usefulness of selected epineurolysis. 25 In addition to replantation, there are often other situations in which vessel repairs in the hand are necessary. Ulnar artery thrombosis may be treated either by excision of the ulnar artery or by an interposition vein graft. Lacerations of the superficial arch of the hand, the radial or ulnar artery, or the digital vessels are common injuries, and repair of these structures is often indicated. Unfortunately, repair of an isolated radial artery or ulnar artery is often only temporarily successful; only about 50 per cent of these repairs stay open permanently. This probably relates to complex flow patterns in the hand, with subsequent stasis at the suture line. However, with the common use of the radial artery for monitoring blood gases and arterial pressures during major surgical procedures, illnesses, or injuries, it would appear to be prudent to repair these arterial injuries when they are encountered. If the patient has an isolated laceration of the ulnar artery that is not repaired, and the radial artery on that hand is catheterized at a later date, the viability of the hand may be in danger.
TRANSFER OF FREE TISSUE A common problem in orthopedics is tissue loss as a result of injury, tumor, or other disorder and may involve skin, skin and subcutaneous
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tissue, or bone loss. Both skin and bone loss were originally treated with free grafts, using split-thickness grafts, pedicle flaps, and free avascular bone grafts. ·However, each of these has its problems, and the advent of microsurgery allowed for the development of new techniques to deal with these problems.
FREE FLAPS Large blocks of skin and subcutaneous tissue may be vascularized either randomly or axially, with a single primary axial vascular supply. Random flaps have classically been transferred as pedicle flaps, waiting until a new blood supply is established for the recipient site before the donor pedicle can be divided. Axial flaps have been transferred much the same way, although these flaps can have a longer length-to-base ratio because of the greater relative blood supply and longitudinal orientation. However, pedicles limit the transfer of these tissues to local areas within the swing of the pedicle or require complex techniques in which the pedicle is transferred on carriers such as the forearm. Transferring tissue in one stage with immediate revascularization at the recipient site obviates these difficulties. The first free flap to be performed was the groin flap. 7 • 13 This axial pattern flap, based on the superficial circumflex iliac artery, has been transferred to multiple locations to provide skin cover over serious wounds. Unfortunately, however, the groin flap has not been as reliable as was hoped, since there is considerable variation in the anatomy of the superficial circumflex iliac artery. 16 Other flaps that have been transferred include the dorsalis pedis flap (based on the dorsalis pedis artery, it may be innervated by the deep peroneal nerve), 24 the forearm flap (based on the radial artery), 26 the saphenous flap (saphenous artery), 2 and the recently described scapular flap. 10 Each of these flaps has had applications, but the latissimus dorsi remains the current model for reliability and versatility. 3 · 11 This can be transferred either as a myocutaneous flap, together with the overlying skin, or as muscle only, which is skin grafted, and which can be of considerable size. The latissimus dorsi muscle is supplied by the thoracodorsal artery, a branch of the subscapular artery. It has a single, anatomically constant, well-defined pedicle that enters the muscle near its proximal insertion. Even if skin over the muscle is taken, the donor site can generally be closed primarily. Loss of this muscle appears to cause no significant defect in the patient's strength or shoulder motion. The artery is large (1.5 to 2.0 mm), is constantly accompanied by one or two similar-sized veins, and may be innervated by repairing the accompanying thoracodorsal nerve to a motor nerve in the recipient area. A pedicle of 5 to 8 em can easily be dissected by ligating the constant branch to the serratus anterior. Coverage of large defects can be efficiently accomplished using these free flap techniques. Although many defects over the tibia, for instance, can be covered with the local gastrocnemius or soleus pedicle myocutaneous flap, the distal tibia is often impossible to reach. This orthopedic injury is
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Figure 2. A, 15,000 volt electrical exit wound in the left knee of a 15-year-old boy. Interior of knee joint exposed. B, Latissimus dorsi muscle transferred in one stage after debridement. Thoracodorsal artery anastomosed to anterior tibial artery. Surface covered with meshed split-thickness skin graft. C, Stable coverage six weeks postoperatively. D, 110° knee flexion present. Patient returned to skiing without knee problems.
common, associated with high-energy, class III tibial fractures. Free flaps do not require awkward immobilization or the application of casts or other external fixation devices, as for cross-leg flaps, but they are not without complication. The latissimus dorsi flap has considerably increased the success rate of free flaps, and generally are 80 per cent or more successful (Fig. 2). Occasional revisions of anastomoses or thrombectomies are necessary. Where possible, arterial inflows of as high a pressure as possible are desirable, and vein grafts may be required to reach high-pressure inflow. In orthopedics, wounds are the most common reason for employing these flaps. However, considerable interest has developed recently in the use of the latissimus dorsi flap, with accompanying muscle, for the treatment of subacute and chronic osteomyelitis in difficult situations. Radical debridement of infected bone and coverage with these flaps if necessary bring in a substantial new blood supply and appear to be beneficial in obtaining control over these difficult infections. Free flaps may also be employed to cover open joints and on occasion may provide sensible skin in the hand. The first web space flap, which is based on the first dorsal metatarsal artery (continuation of the dorsalis pedis artery) has proved most useful. This flap is innervated by the deep peroneal nerve, and very useful two-point
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discrimination can be achieved when this flap is innervated in its new location. 24 TOE TRANSFER
The transfer of digits, particularly the toe-to-thumb transfer for replacement of the thumb lost because of trauma or because of congenital malformation, has provided an innovative way of coping with loss or congenital absence of the digit. Standard methods of thumb reconstruction involve iliac bone grafts and pedicle grafting, followed by island flaps from an adjacent finger to provide some sensation. The transfer of a whole great toe or second toe, however, offers the opportunity for early establishment of properly oriented sensibility, for motion, and, in the case of the congenital malformation, for growth. These procedures are complex but have been reasonably reliable in the hands of those experienced in microvascular techniques. 4• 39• 40 VASCULARIZED BONE GRAFTS
~
Bone grafts are widely used in orthopedic surgery, in such operations as arthrodesis of joints, treatment of fracture non unions, and reconstruction of bone loss after trauma or surgery. The standard bone graft in which cortical or cancellous bone is taken from a donor site and transplanted to a recipient site depends on the graft acting as a scaffold. Over a long period of time, the graft is incorporated into new bone and replaced. There is a relatively low survival of the bone cells in this setting, since they must depend on deriving their nutrition by diffusion from the surrounding tissue. When a tubular bone such as a fibula is used to reconstruct a segment of missing bone, the graft must be replaced from the ends by the process known as "creeping substitution." Although the ends of the bone may heal, this avascular bone graft is replaced by a process of resorption and new bone formation. In general, the resorption proceeds more rapidly than new bone formation, and the large resorption cavities formed may mechanically weaken the bone and result in fracture, particularly at six to nine months. As long as two years is required for complete replacement of a graft of this type. Although avascular cancellous grafts are incorporated more rapidly because of the larger surface area, they offer little structural strength and act in large part as stimulations to new bone growth. Some of these problems were alleviated when the vascularized bone graft was conceived. In this technique, a bone is transplanted, together with the blood vessels that supply it. With the anastomosis of these vessels to those locally in the recipient area, the bone has an immediate new blood supply. The process of replacement is therefore eliminated, and, theoretically at least, the bone should heal by the standard process of fracture healing at the two ends. By the use of this technique, many large segmental defects can now be approached with greater certainty. Although there was concern initially that the bone cells (osteocytes) would not survive the
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Figure 3. A. A 35-year-old man with saw injury to left forearm, transecting ulnar artery and nerve. Segmental defect in ulna. B, Preoperative arteriogram, with arrow on transected ulnar artery. External fixation in place. C, Vascularized fibula harvested with surrounding muscle cuff, on the peroneal artery and vein (under probe). D, Postoperative arteriogram, showing fibula in place with peroneal artery patent. Arrow indicates anastomosis between peroneal artery and ulnar artery. (Case courtesy of Richard I. Burton, M.D., University of Rochester, Rochester, New York.)
ischemia and transplantation process, it has been shown that these cells are quite resistant and can survive 25 hours of ischemia under controlled experimental conditions. 5 Joints have also been transplanted and epiphyseal growth demonstrated. 23 The fibula is the most commonly used free vascularized bone graft, as described by Weiland and others. 9• 31 • 36 • 37 The fibula is supplied by a single intramedullary nutrient artery and a periosteal blood supply that approaches the bone through the surrounding muscle cuff. The fibula is harvested through a posterolateral incision, and the peroneal artery is isolated. The fibula is then dissected free, leaving a surrounding 0.5 to 1 em muscle cuff to protect the periosteal blood supply. After the fibula has been divided at both ends, flow of blood from the medullary cavity can be demonstrated. The vessels are then divided, the fibula is transplanted to its new location, and the vessels anastomosed. This technique is useful for such problems as congenital pseudarthrosis of the tibia, segmental defects in the tibia or femur, and reconstruction of the bones of the upper extremity after resection for tumor or trauma. Standard orthopedic techniques are used in fixing the bone at both ends (Fig. 3). In some instances, such as in facial reconstruction, a more slender and less bulky bone is required, and for this, the rib is the most appropriate. The blood supply of the rib is derived from two major sources. The first is the posterior artery, which supplies a nutrient vessel to the center of the bone. The second is from the more anterior intercostal artery, which supplies the exterior of the bone through a periosteal cuff. Most surgeons use the anterior vessel, since dissection of the posterior intercostal artery is far posterior near the spine. Experimentally, the inclusion of both vessels
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Figure 4. A, Osteomyelitis and poor skin coverage of right medial malleolus three years after electrical injury. B, Radical debridement of soft tissue and bone, leaving 8 X 10 em defect. C, Latissimus dorsi free Hap with split-thickness skin grafts. Stable skin coverage provided, with new highly vascular tissue adjacent to bone. No further drainage. Flap will shrink by at least 40 per cent over first three months because of denervation.
does not appear to influence the healing of these grafts. 14 The rib is particularly suitable for reconstruction of defects in the mandible and can be molded to the curves required. Much attention has been given to composite grafts in which bone is included with soft tissue. The groin flap based on the superficial circumflex iliac artery can be taken together with a piece of underlying ilium, but this dissection is complicated by variations in anatomy. 1 Taylor has described composite bone grafts taken on the deep circumflex iliac artery, in which the anatomy is much more constant, the vessels are larger, and the blood supply to the bone more reliable. 32 • 33 However, many surgeons now depend on vascularized soft tissue coverage of segmental bone defects, such as seen in the tibia, with free flaps or local myocutaneous flaps. Underlying bone defects of 6 em or less are then reconstructed using cancellous bone from the pelvis. Defects of larger size are reconstructed with blocks of corticocancellous bone from the ilium, and very large defects are treated with vascularized fibular grafts (Fig. 4).
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CONCLUSION In orthopedics, as in many other specialties, the advent of microsurgical procedures has encouraged innovative solutions to difficult problems. Replantation was the first clinical success and was rapidly followed by the development of other procedures, such as free tissue transfers. As these techniques become more refined, there will undoubtedly be many more applications. REFERENCES 1. Acland, R. D.: The free iliac Hap. Plast. Reconstr. Surg., 64:30, 1979. 2. Acland, R. D., Schustennann, M., Gadira, M., et al.: The saphenous neurovascular free Hap. Plast. Reconstr. Surg., 67:763-774, 1981. q. Bostwick, J., Nahai, F., Wallace, J. E., et al.: Sixty latissimus dorsi Haps, Plast. Reconstr. Surg., 63:31, 1979. 4. Buncke, H. J., and Shah, K.: Toe-digital transfers. In Serafin, D., and Buncke, H. J. (eds.): Microsurgical Composite Tissue Transfer. St. Louis, C. V. Mosby, 1979, pp. 573-586. 5. Berggren, A., Weiland, A. J., and Dorfinann, H.: The effect of prolonged ischemia time on osteocyte and osteoblast survival in composite bone grafts revascularized by microsurgical anastomoses. Plast. Reconstr. Surg., 65:290, 1982. 6. Chow, J. A., Bilos, Z. J., and Chunpropah, B.: Thirty thumb replantations: Indications and results. Plast. Reconstr. Surg., 65:626-630, 1979. 7. David, R. K., and Taylor, G. 1.: Distant transfer of an island Hap by microvascular anastomoses: A clinical technique. Plast. Reconstr. Surg., 52:111-117, 1973. 8. Ger, R.: Muscle transposition for treatment and prevention of chronic post-traumatic osteomyelitis of the tibia. J. Bone Joint Surg., 59A:784, 1977. 9. Gilbert, A.: Vascularized transfer of the fibular shaft. Int. J. Microsurg., 1:100-102, 1978. 10. Gilbert, A., and Teot, L.: The free scapular Hap. Plast. Reconstr. Surg., 69:601, 1982. 11. Gordon, L., Buncke, H. J., and Alpert, B. S.: Free latissimus dorsi Haps with splitthickness skin graft cover. A report of 16 cases. Plast. Reconstr. Surg., 70:173, 1982. 12. Hayes, M. G., and Urbaniak, J. R.: Management of bone in replantation surgery. AAOS Symposium on Microsurgery. Practical Use in Orthopaedics. St. Louis, C. V. Mosby, 1979, p. 96. 13. Harii, K., Ohmori, K., Torii, S., et al.: Free groin skin Haps. Br. J. Plast. Surg., 28:225237, 1975. 14. Hadel, R. M., Hatlurn, R. S., Rodrigo, J., et al.: The functional vascular anatomy of rib. Plast. Reconstr. Surg., 70:578-585, 1982. 15. Jupiter, J. B., Tsai, T. M., and Kleinert, H. E.: Salvage replantations-of lower limb amputations. Plast. Reconstr. Surg., 69:1-8, 1982. 16. Katai, K., Kido, M., and Numaguchi, Y.: Angiography of the iliofemoral arterio-venous system supplying free groin Haps and free hypogastric Haps. Plast. Reconstr. Surg., 63:671-679, 1979. 17. Kleinert, H. E., Juhala, C. A., Tsai, T. M., et al.: Digital replantation-selection, techniques, and results. 0RTHOP. CLIN. NORTH. AM., 8:309-318, 1977. 18. Lesguoy, M. A.: Successful replantation of lower leg and foot, with good sensibility and function. Plast. Reconstr. Surg., 67:760--765, 1979. 19. Lister, G.: Interosseous wiring of the digital skeleton. J. Hand Surg., 3:427-435, 1978. 20. McDonald, H. D., Buncke, H. J., and Goodstein, W. A.: Split-thickness skin grafts in microvascular surgery. Plast. Reconstr. Surg., 68:731, 1981. 21. Malt, R. A., and McKahn, C.: Replantation of severed arms. ].A.M.A., 189:716, 1964. 22. Mathes, S. J., Alpert, B. S., and Chang, N.: Use of the muscle Hap in chronic osteomyelitis: Experimental and clinical correlation. Plast. Reconstr. Surg., 69:815, 1982. 23. Mathes, S. J., Buchanan, R., and Weeks, P. M.: Microvascular joint transplantation with epiphyseal growth. J. Hand Surg., 5:586, 1980.
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24. May, J. W., Chait, L.A., Cohen, B. E., et al.: Free vascularized Hap from the first web space of the foot in hand reconstruction. J. Hand Surg., 2:387-393, 1977. 25. Millesi, H.: Surgical management of brachial plexus injuries. J. Hand Surg., 2:367-379, Sept. 77. 26. Mulhauer, W., Herhdl, E., and Stock, W.: The forearm Hap. Plast. Reconstr. Surg., 70:336, 1982. 27. Ostrup, L. T., and Frederickson, J. M.: Distant transfer of a free living bone graft by microvascular anastomoses: An experimental study. Plast. Reconstr. Surg., 54:274, 1974. 28. Report of the American Replantation Mission to China. Plast. Reconstr. Surg., 52:476, 1973. 29. Sixth People's Hospital, Shanghai: Replantation of severed fingers: Clinical experience in 162 cases involving 270 severed fingers. July 1963. 30. Tarnai, S.: Digital replantation: Analysis of 163 replantations in an 11-year period. Clin. Plast. Surg., 5:195, 1978. 31. Taylor, G. 1., Miller, G. D. H., and Ham, F. J.: The free vascularized bone graft-a clinical extension of microvascular techniques. Plast. Reconstr. Surg., 55:533, 1975. 32. Taylor, G. I., Townsend, P., and Corbett, R.: Superiority of the deep circumflex iliac vessels as the supply for free groin Haps: Experimental work. Plast. Reconstr. Surg., 64:595-604, 1979. 33. Taylor, G. 1., Townsend, P., and Corbett, R.: Superiority of the deep circumflex iliac vessels as the supply for free groin Haps: Clinical work. Plast. Reconstr. Surg., 64:745759, 1979. 34. Tupper, J.: Fascicular nerve repairs. In Jewett, D. L. and McCarroll, H. R. (eds.): Nerve Repair and Regeneration, St. Louis, C. V. Mosby, 1980. 35. Urbaniak, J. R.: Replantation of amputated parts-techniques, results, and indications. AAOS Symposium on Microsurgery. Practical Use in Orthopaedics. St. Louis, C. V. Mosby, 1979. 36. Weiland, A. J., 'and Daniel, R. K.: Microvascular anastomoses for bone grafts in the treatment of massive defects in bone. J. Bone Joint Surg., 61A:98-104, 1979. 37. Weiland, A. J., Kleinert, H. E., Kutz, J. E., et al.: Free vascularized bone grafts in surgery of the upper extremity. J. Hand Surg., 4:129-144, 1979. 38. Weiland, A. J., Villareal-Rios, A., Kleinert, H. E., et al.: Replantation of digits and hands: Analysis of surgical techniques and functional results in 77 patients with 86 replantations. J. Hand Surg., 21:1-12, 1977. 39. Yang, D., and Gu, Y. : Thumb Reconstruction utilizing second toe transplantation by microvascular anastomosis: A report of 78 cases. Chin. Med. J., 92:295, 1979. 40. Yoshimura, M.: Toe-to-hand transfer. Plast. Reconstr. Surg., 66:74-83, 1980. 41. Young, L., Wray, P. C., and Weeks, P. M.: A randomized prospective comparison of fascicular and epineural digital nerve repairs. Plast. Reconstr. Surg., 68:1, 89-92, 1981. Department of Orthopaedics Rhode Island Hospital Brown University Providence, RI 02912