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Figure 1. Advances in microsuture such as the 10-0 suture have made limb reconstructive procedures possible. This suture is compared to the diameter of a human hair. |
"I'm a doctor, Spock, not a magician!" - DeForest Kelley in Star Trek
We have all seen futuristic situations where a "magic wand" wielding physician saves an individual badly traumatized while poignant music plays in the background. These twenty-third century physicians miraculously restore form and function requiring little or no recovery or rehabilitation. Unfortunately in 1998, such procedures do not exist. Traditionally, "limb salvage" procedures have applied to tumor resection with application to the lower extremity. The upper extremity is also involved in devastating traumatic, infectious, inflammatory, and tumorous conditions that result in bony or soft tissue loss. Limb salvage may also be applied to the upper extremity in case where primary resection has left a deficit of bone or soft tissue requiring secondary reconstruction. Cooperative ventures by orthopaedic and plastic surgeons have resulted in this new field of osteoplastic reconstruction1. Osteoplastic reconstruction uses bone and soft tissue techniques to replace tissue loss with bone grafting and tissue transfers to restore the form and function of the upper extremity. Advances such as the operating microscope, fine suture material, and internal fixation have allowed reconstruction with early return of form and function (Figure 1).
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Figure 1. Advances in microsuture such as the 10-0 suture have made limb reconstructive procedures possible. This suture is compared to the diameter of a human hair. |
The upper extremity presents significant challenges to the reconstructive surgeon. The hand and the face are the only two body parts routinely presented for public inspection. Deformity or tissue loss is readily noticed and may result in social stigmatization. Loss of "normal " appearing hands frustrates our patients. Restoration of function requires an understanding of the stability, mobility, and strength not present in the lower extremity. The hand and arm provide us with the ability to express emotion, throw a football, and craft a fine watch without conscious thought. Tissue loss in the upper extremity often requires tendon, nerve and vascular reconstruction in addition to skin and bone in order to restore these functions. This review examines four "salvage" situations in the upper extremity and current techniques used to restore maximum function.
Perhaps the classic "salvage" procedure in the hand is the treatment of failed tendon repair. In the early days of hand surgery, injuries to the flexor tendons in the digits were said to have occurred in "No man's land." In 1922, Sterling Bunnell, the father of modern tendon surgery wrote, "If the flexor tendons are severed in a finger opposite the proximal phalanx, one cannot join them by suture with success, as the junction will become adherent in the flexor channel and will not slip2." Despite seventy years of clinical experience and basic research, the controversy over tendon repair rages. The unique linear arrangement of the tendon fibers is poorly suited for holding simple sutures. Even today, up to 10% of repairs suffer catastrophic rupture or become densely adherent to the surrounding sheath with loss of most if not all mobility. Flexor tendon grafting and tenolysis will repair most of these situations. However, many patients demonstrate severe scarring of the sheath or tendon gapping that is not amenable to repair.
In these cases, a two-stage tendon reconstruction salvages digital flexion. Criteria for success include supple joints with full passive range of motion and an intact tendon sheath. The sheath provides a lubricated environment for the flexor tendon while preventing bowstringing. Bowstringing decreases mechanical efficiency and mobility of the tendon and often causes severe interphalangeal joint contracture. The two-stage procedure allows separate release of joint and sheath reconstitution prior to actual tendon grafting.
The procedure takes advantage of the body's response to a silicone tube (Figure 2). In 1965, Hunter first published a report on the "pseudosheath " formed in response to movement around a tube in the paravertebral muscles in a dog model3. Active motion generated a synovial like sheet of tissue that was capable of supporting tendons with nutrition and lubrication. Salisbury reported the first clinical study in 19754 and research continues today. The first stage of the procedure involves complete exposure of the flexor tendons in the injured digit. Damaged tendons are removed from the sheath, joint contractures released, and critical thickenings or pulleys at the level of the mid- proximal and middle phalanges are inspected. Deficient pulleys are reconstructed with excised tendon tendon wrapped around the phalanx and secured. A four or five millimeter silicone tube is threaded from the distal phalanx into the palm and then into the forearm. All wounds are closed and vigorous passive motion of the digit performed for six to twelve weeks at home and in hand therapy to maintain joint mobility and form the sheath. At the second procedure, a free tendon graft is harvested. The palmaris longus tendon is most popular though toe extensors and the plantaris tendon have been used successfully. The digit is opened at the tip only. A second incision in the forearm reveals the proximal end of the tube and sheath. Attaching the tendon to one end of the implanted rod allows it to pass the length of the pseudosheath. The new tendon is secured through drill holes in the distal phalanx and is interwoven through an adjacent profundus tendon proximally. Tension is set slightly tighter than the normal resting posture of the finger. Therapy with passive motion is begun within a day or two and may be replaced by active motion within three to four weeks. Return to manual lifting takes from eight to twelve weeks.
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Figure 2. Hunter rod designed to replace native tendon in staged tendon grafting. |
Results with this technique demonstrate its true "salvage "nature. Mobility may reach 90 degrees of flexion at the metacarpal phalangeal joint- near normal. However the proximal interphalangeal joint mobility ranges from 50 to 85 degrees with normal up to 105 degrees. The distal joint mobility is also less than normal and strength is diminished by a third5. However, useful functional motion is achieved with little pain and few complications reported. Studies are now in progress to determine the long-term viability of a synthetic tendon consisting of a heavy Dacron core surrounded by silicone as an actively mobile permanent implant. Some success has been reported though rupture of the prosthetic tendon is significant concern.
Injuries to the brachial plexus are rare but potentially devastating injuries to the upper extremity. These injuries occur most frequently following vehicular trauma especially motorcycle and snowmobile injury where occupants are ejected from the vehicle. The injury occurs when the neck is forcibly abducted from the shoulder placing excessive traction on the plexus and avulsing the root from the plexus or rupturing the nerve within the plexus. Diagnosis involves careful serial physical exams to distinguish a neurapraxia type injury, where function returns quickly, from a more severe and permanent nerve rupture or avulsion. Perhaps the two most valuable tools are CT myelography and EMG/ nerve conduction. The CT demonstrates absent roots or a pseudomeningocoele in root avulsions. EMG/NCS will document loss or return of muscle innervation and be performed at one to two month intervals beginning at 2 to 3 weeks for best reliability.
Many of these injuries involve the upper trunk of the plexus, which includes C5 andC6 roots. These injuries will involve loss of shoulder and elbow control. Restoration of shoulder abduction and elbow flexion restores much of the basic function at these joints and is the focus of nerve reconstruction efforts in brachial plexus surgery6. These efforts may involve neurolysis, nerve grafting or neurotization. Neurotization involves the microanastomosis of a functioning proximal to a nonfunctioning distal nerve to restore motor function.
The decision to operate on the brachial plexus requires knowledge of the anatomy as well as surgical alternatives. The decision should be made by six months following injury and should be based on a failure of progression in nerve recovery. Beyond six months nerve regenerating nerves may not reinervate muscle tissue before receptor sites atrophy. Contractile function in skeletal muscle is permanently lost eighteen months after loss of innervation.
Several successful techniques have been developed which illustrate the broad options available to restore function, in this case elbow flexion. Early nerve exploration with neurolysis and grafting formed the basis of upper plexus surgery until the 1960s. Removal of fibrosis and placement of sural nerve grafts within intraneural ruptures resulted in limited return of function. Younger patients fared better than older. Unfortunately, nerve root avulsions from the spinal cord were not repairable and remain experimental to this date. Microsurgical nerve reconstruction in the 1970s by Millesi and Narakis heralded the dawn of plexus reconstruction6 (Figure 3). They pioneered the use of intercostal nerves to reanimate the elbow flexors and shoulder abductors via the dorsal scapular and musculcutaneous nerves .
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Figure 3. Schematic of intercostal nerve transfer for brachial plexus palsy. |
The surgical technique involves harvesting the motor portion of the intercostal nerves 3 and 4 via a thoracotomy incision. The nerves are harvested back to the most posterior aspects of the rib and tranposed into the upper arm subctaneously. Direct anatomosis with the dorsal scapular nerve is performed microscopically. The sural nerve may serve as an interpositional graft if necessary. Postaoperative immobilization is brief, allowing for wound and nerve suture healing. Passive motion of the extremity occurs until active motion is detected.
Initial movements occur approximately four to six months following reconstruction and are often accomplished by asking the patient to "cough". With training the muscles respond to less artificial stimuli and forty to sixty degrees of shoulder abduction and zero to ninety degrees of elbow flexion with the ability to lift five to fifteen kilograms. In recent years, other donor nerves including the spinal accessory, phrenic, and contralateral C7 nerve root have been used with success to restore muscle function.
When nerve procedures are impossible, stabilization of the shoulder and elbow may involve selective joint fusion and tendon transfers. Shoulder stability may be accomplished by moving a musculotendinous unit such as the rhomboids, teres major, or latissimus to the proximal humerus to gain abduction. These are most beneficial in children. Adults often choose a glenohumeral fusion, which allows scapular movement to control the proximal limb. Transferring the pectoralis major or latissimus dorsi gains elbow flexion to the forearm to gain power flexion. Less complicated but less strong elbow flexion transfers include triceps to biceps transfer and displacement of the flexor pronator group proximally on the humerus to increase elbow flexion. All these procedures assume at least satisfactory hand function. Unfortunately, loss of sensibility in the hand may obviate the need for any of the above procedures. In this case, amputation and prosthetic fitting are the best procedure.
Before antibiotics, infection was the leading cause of bone loss in the upper extremity. In the past twenty years, high-energy trauma associated with motor vehicle accidents and gunshot wounds has replaced infections the leading cause of structural bone loss. Structural bone loss indicates disruption of a major portion of the upper limb that is not amenable to direct repair. Such loss usually resulted in a stiff limb with impaired function. New techniques of bone grafting and internal fixation help to restore stability and mobility in the limb. The foundations of this treatment are maintenance of length, support of articular congruency, and maintenance of soft tissue coverage.
Traditional bone grafting sites included the iliac crest, tibial crest, and proximal ulna. These areas provided nonvascularized cancellous and occasionally nonvascularized cortical struts. These grafts filled bone gaps but required a slow process of "creeping substitution" for revascularization. Gelberman and others demonstrated that fracture gaps of greater than six centimeters resulted in late bone fracture when treated with nonvascularized grafting. Microsurgical advances led to the use of vascularized bone grafting in the 1980s. The workhorse vascularized bone grafts are the diaphyses of the fibula and the iliac crest. While harvesting these grafts with their associated blood vessels is a longer procedure, the maintenance of blood flow in the graft improves healing rates of diaphyseal defects to greater than 90 percent8. Fibular grafts greater than twenty centimeters are possible with minimal donor site morbidity.
The vascularized fibula is harvested using a lateral approach to the leg. The fibula is exposed and its periosteal envelope left intact, different from traditional grafting techniques. The peroneal vessels are located posterior to the interosseous membrane and may form a 5-8 centimeter vascular pedicle to allow significant flexibility in graft placement. Newer plate and screw techniques provide for rigid fixation of the graft while the vascular supply promotes early healing (Figure 4).
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Figure 4. Vascularized fibula graft in place for repair of an eight centimeter defect in the radius. |
Another option for bone salvage in the upper extremity is distraction osteogenesis. An osteotomy of intact bone adjacent to a defect is slowly transported as a mobile segment using an adjustable external fixator. Distraction of one millimeter per day results in formation of woven bone that consolidates into harder cortical bone over time. This technique is especially useful in correcting angular deformity and often requires no secondary grafting. Upper extremity application is especially useful in lengthening of the thumb metacarpal. Diaphyseal lengthening in the forearm has been complicated by difficulty in pin placement. Neurovascular structures surround the radius and ulna leaving few safe locations for pin placement. These fixators are labor intensive. Pin care and meticulous attention to a lengthening schedule are inconvenient for patients. Almost all cases have transient infections or traction symptoms on nerves.
Internal fixation of the upper extremity supplements the benefits of bone grafting. Traditional percutaneous wire fixation of fractures provided little stability especially in periarticular fractures. This often resulted in loss of joint alignment, stiffness, and pain. Fusion of the joint was the ultimate salvage. Newer fracture fixation devices including screws with a shaft diameter as small as 1.2 mm are available for the smallest fractures of the digits. Rigid fixation and preservation of periosteal blood supply allow for early healing and range of motion in complex fracture patterns. Early motion promotes cartilage healing and prevents capsular stiffness allowing normal joint motion.
Bone stimulation offers a new avenue for bone salvage. Tissue engineering is most advanced in the area of bone regeneration. Bone substitutes such as coral or hydroxyapitite form a scaffold or osteoconductive surface for bone healing and are commercially available. Union rates of 70 to 80 per cent occur when these are used in small (< 2cm) gaps. These may be impregnated with bone morphogenic proteins or stem cells which offer an osteoinductive substance to stimulate new bone growth. Platelet derived growth factor, Transforming growth factor_B, and the interleukins have all been used experimentally9. Clinically available proteins were introduced in 1997. Reports of 90 to 100 per cent healing in difficult nonunions exceed the efficacy of cancellous bone grafting and when combined with internal fixation are effective in larger bone gaps.
Salvage of joint function in the upper extremity remains a difficult and unanswered problem. The small articular surfaces with complex curvatures have limited development of joint prostheses. While the elbow and shoulder total joint prostheses exist; experience with these prostheses is not as well reported as in total hips and knees. Total wrist prostheses are notorious for loosening and failure especially in younger post-traumatic joints. To date, the best candidates for joint replacement in the upper extremity are those individuals with severe rheumatoid arthritis. While medical therapies improve each year, "wet" rheumatic joints may defy medical and surgical attempts at preserving articular cartilage. Perhaps the best-studied joint "salvage" in rheumatoid arthritis is the metacarpal phalangeal joint.
Typically, patients with rheumatoid arthritis exhibit deformities of volarflexion and ulnar deviation at the MP joint. Extrinsic forces in this deformity include radial deviation of the wrist and attenuation of the extensor tendons. Intrinsic forces include stretching of the radial collateral ligament and the natural drift of the fingers across the metacarpal head with flexion. With time the contractures become fixed and the efficiency of grasp decreases. Joint erosions develop and pain ensues. Activities of daily living such as buttoning a shirt or holding a pen become difficult.
MP joint replacement is primarily performed to return function and relieve pain. The procedure restores a functional arc of motion, relieves pain, and corrects deformity. The patient must be cautioned that a "normal" joint will not return. Historically, joint replacement using metal or polyethylene components failed secondary to shear stresses, which causes prosthesis loosening even when cemented. Swanson is credited with the development of a silicone hinge, which stabilizes the MP joint while forming a strong reactive capsule that prevents implant failure10. His surgical technique revolutionized the treatment of hand deformities in rheumatoid arthritis. The joint is approached dorsally and contracted capsule and intrinsic tendons are released on the ulnar side. Gentle resection of the metacarpal head and base of the proximal phalanx follows a thorough joint synovectomy. Both bony canals are gently reamed and trial prostheses placed. Often, all four finger MP joints are replaced (Figure 5 ). Once bony stability is achieved, final implants are placed. Soft tissue reconstruction consists of reefing or reattachment of the radial collateral ligament and centralizing of the extensor tendons. Postoperative care consists of a custom splint designed to protect against flexion and ulnar deviation of the digits. These splints may remain for up to six months postoperatively to prevent recurrence of the deformity.
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Figure 5. Silastic
implants in place for MP joint arthroplasty. |
Results of MP arthroplasty are well documented for function and satisfaction. Most recently, Kirschenbaum et al studied one hundred and forty four implants at ten years postoperatively11. They found an arc of motion of fifty degrees equal to the preoperative mobility. However, the arc occurred in a more function portion of MP motion from -10 degrees of extension to sixty degrees of flexion. Ulnar drift recurred at a minor level (4-10 degrees) that did not interfere with function tasks. Grip strength did not significantly improve. This was attributed to other deformities within the hand. 95% of patients were satisfied and would have the procedure again.
While surgical intervention is the cornerstone of limb salvage in the upper extremity, proper rehabilitation is the key to maximizing function. The old saying that good therapy makes a good procedure better is quite applicable to the complex procedures discussed in this review. Certified hand therapists have additional training and interest in these problems and are critical in training the patient in the use of the "new" extremity. Their role is crucial in the following areas: 1) wound care and edema control; 2) splinting that maximizes function and minimizes contracture; 3) mobilization both active and passive; 4)desensitization and sensory reeducation; and 5) work and activity of daily living modification. The therapist may spend five to ten hours per week with the patient and may be the first person aware of complications such as wound infection. They also provide measures of success such as grip and pinch strength, range of motion, and two-point discrimination. Splinting is an art as well as a skill. With the complicated geometry of the hand, subtle differences in splints may be beneficial or detrimental to ultimate outcome. Mobilization and sensory reeducation are most important following tendon and bone repair and may decrease the need for secondary reoperation for adhesions. Finally, the therapist made provide education about alternative ways to perform job activities and alternative devices to make such activities possible. Many therapists are trained in job and functional analysis and help determine a patient's readiness to return to work.
No discussion of limb salvage in the upper extremity would be complete without a discussion of amputation. Amputation and prosthetic use represents the ultimate in limb salvage. Indications for amputation include severe infection uncontrollable by standard methods, an anesthetic flail limb, an amputated part not suitable for replantation, and extracompartmental malignant tumor. Necrotizing fasciitis, power tool avulsion injuries, and epitheliod sarcoma may require amputation to preserve life, control pain, and begin rehabilitation.
Prosthetic wear in the upper extremity enjoys some success. However, the complexity of movement has prevented the universal acceptance enjoyed by lower extremity prostheses. Many digital amputations are well tolerated and require only comfortable tip coverage to resume normal activity. In fact, far fewer replantations are performed now especially for isolated digital amputations. Occasionally, cosmetic finger prosthesis will improve cosmetic appearance of the hand. The exception is the thumb. Thumb opposition pinch is so widely used that reconstructive efforts are worthwhile. Efforts have included metacarpal lengthening and first web space deepening, bone graft with free flap coverage, or free toe to thumb transfer. All produce a functional result.
Amputation above the hand may be optimized by mechanical or myoelectric prostheses. Mechanical devices are light weight, driven by shoulder or arm positioning and can be provided with a variety of attachments for specific tasks. Myoelectric prostheses are driven by surface electrical impulses and may better simulate voluntary opening and closing of the hand. Unfortunately, these devices are heavier and more expensive and may not be as well tolerated especially in above elbow amputation.
When treating patients with amputations in is important to maintain contact among surgeon, prosthetist, hand therapist and primary care physician. Posttraumatic stress is a common occurrence and may be relieved by psychological intervention. Pain is a common postoperative problem. Phantom pain may be managed pharmacologically and with desensitization. Posttraumatic neuromas may require reoperation.
Limb salvage procedures discussed here include salvage for tendon, nerve, bone, and joint pathology. Often many of the techniques are combined to produce the maximum strength while preserving stability and function while preventing pain during normal life activities. The surgery may be demanding and the rehabilitation difficult. Still the rewards are great when a useful upper extremity results. The future holds great promise as tissue engineering brings us new bones, cartilage, tendons, and nerve regeneration. Perhaps these "magical" cures will someday eliminate the need for "salvage" procedures.
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