37 Restoration of upper extremity function in tetraplegia

Synopsis

For people with tetraplegia, restoration of independence is the primary goal.

Treatment must be individualized because neurologic deficits vary greatly between patients and within individuals (one arm is different from the other).

The hands of people with tetraplegia represent a critical residual resource.

Restoration of function requires a multifaceted approach combining physical therapy, assistive devices, and surgery. including tendon transfer, tenodesis, functional electric stimulation and arthrodesis.

These procedures have been shown to improve functional independence.^1,²

These procedures are underutilized.³

Strengthening connections between spinal cord injury specialists and upper limb surgeons represents an opportunity to improve access to this care.

Introduction

Surgery on the upper limb of people with tetraplegia requires special consideration because the hand represents a critical residual resource.⁴ Their upper limbs take on new functions different from any other patient in that they must “walk on their hands.” Given the importance of the upper limb, surgery must be carefully planned and be the culmination of a long rehabilitative process involving a team. The patient must understand what can be accomplished and realize that the functional improvements will not result in a “normal arm” but as Dr Sterling Bunnell, the father of upper limb surgery in the United States said, “for those who have nothing a little is a lot.”⁵

Basic science/disease process

Today, the most common mechanisms of cervical spine injury (SCI) are motor vehicle accidents, falls, especially in the elderly, and sports injuries. The functional consequences are primarily determined by the anatomic level of and the completeness of the injury. Modern acute care of these injuries has so progressed that almost all survive their injury and thus face a lifetime in a greatly altered state of existence. Every tetraplegic patient suffers some loss of upper limb function and for most, their upper limbs represent, aside from their brain, their most important functional asset.

Though the upper limb surgeon often does not participate in the initial management of the SCI patient, the acute rehabilitation focuses on the upper limbs. Special care is taken to prevent the onset of contractures of fingers, wrist, or elbow. Even a relatively mild elbow contracture can inhibit independent transfers.⁶ Fortunately, well-educated therapists are aware of the need for protective splinting right after injury. The shoulder must also be protected as the patient learns to adjust to their injury. Pulling patients, poor posture, or falls can result in shoulder injuries that ultimately limit independence. Indeed the majority of people with tetraplegia have shoulder pain at the end of their acute rehabilitation.⁷ Early attention to the upper limb provides the best long-term function.

Classification of the tetraplegic upper extremity

Cervical spinal cord injury has been classified in many ways, including by the skeletal level of injury or according to the most distal remaining functioning cervical root. However, this classification system is too general for hand surgeons because no two patients are exactly alike. Injury pattern can differ between those with the same skeletal level of injury and each patient often has different function between the right and left arm. In order to develop useful recommendations for treatment of the upper limb, it was necessary to develop a more precise method for classifying the upper limb in the tetraplegic patient. From these needs arose the International Classification, which is based on the limb’s remaining useful motor and sensory resources (Table 37.1). The motor function assesses the number of strong muscles under volitional control below the elbow. To be counted, the muscle must have grade 4 or 5 Medical Research Council strength. The grade 4 level was chosen because a grade 4 muscle can be transferred with the expectation that it will be able to perform useful work. A grade 3 muscle loses so much of its power in transfer that it cannot be reliably expected to do useful work after transfer.

Table 37.1 International classification for surgery of the hand in tetraplegia

Sensibility	Motor	Description
O or Cu group	Characteristics	Function
0	No muscles below elbow suitable for transfer	Flexion/supination of elbow
1	Br
2	ECRL	Extension of wrist (weak or strong)
3	ECRB	Extension of wrist
4	PT	Extension and pronation of wrist
5	FCR	Flexion of wrist
6	Finger extensors	Extrinsic extension of fingers, partial or complete
7	Thumb extension	Extrinsic extension of the thumb
8	Partial digital flexors	Extrinsic flexion of the fingers, weak
9	Lacks only intrinsics	Extrinsic flexion of the fingers
X	Exceptions

Caution: it is not possible to determine ECRB strength without surgical exposure. Br, brachioradialis; ECRL, extensor carpi radialis longus; ECRB, extensor carpi radialis brevis; PT, pronator teres; FCR, flexor carpi radialis.

Moberg ^8,⁹ also encouraged a consideration of remaining sensory resources as well. If sufficient proprioception remains in any part of the hand (typically the thumb and index fingers), the patient can control his hand without having to keep it in view. If the hand lacks proprioception, the patient can rely on his eyes to direct his hands. However, lack of proprioception limits the patient in performing bi-manual activities. Today static 2-point discrimination of less than 12–15 mm is acknowledged as indicating the presence of proprioception. The International Classification recognizes the presence or absence of proprioception by including codes to indicate whether afferent control resides in the hands, termed “cutaneous, or Cu” or only in the eyes of the patient, termed “ocular, and abbreviated as “O.”

Later, the International Classification scheme was extended to include a determination of the presence or absence of active elbow extension. This system was adopted by the International Federation of Hand Surgery Societies ¹⁰ and it is used by essentially all surgeons involved in the care of the upper extremities of these patients.

Patient presentation and patient selection

Forming a team

Moberg stressed the need to develop a “critical mass” of likeminded professionals into a team that should include physiatrists involved in the rehabilitation and long-term care of people with tetraplegia. Critical to the success of an upper limb team are well-trained therapists, either physical therapists or occupational therapists (preferably both). The hand and upper extremity surgeon provides the technical expertise. Others including social workers and psychologists may offer additional support to the team. The patient’s support group including family or attendant is the key to success. The central member of the team is the patient.¹¹^–¹³

The role of the professionals in this team is relatively clear. The physiatrists assist in determining the appropriateness of the patient for surgery as well as when to time surgery relative to overall rehabilitation goals and schedules. The therapist frequently serves as the patient’s advocate. He or she knows the patient better than anyone else and most importantly, the patient’s expectations voiced or not.

For the patient, upper extremity surgery can have a large emotional impact. Some patients are concerned about altering their anatomy because they are waiting for the cure for SCI. While the goal of surgical reconstruction for the upper extremity is greater function, the patient must be willing to lose temporarily some of their hard won independence during the postoperative rehabilitation. For family and attendants this greater period of dependence translates into more inconvenience and effort. All the team members must play a role in the decision-making process and must share in the frustrations as well as the rewards.

The hand and upper extremity team should become part of the routine evaluation of even newly injured patients. The cervical cord injured patient arrives at a rehabilitation facility or spinal cord injury unit usually with fairly supple upper limbs though with no or only minimal volitional movement. Once the patient’s vertebral injury has become stabilized and the patient can be up in a wheelchair, an assessment by the upper extremity team takes on new meaning. By the 3rd or 4th month following injury, the eventual functional level is usually clearly established for the majority of patients.¹⁴ At this time, the patient’s upper limb function is assessed and the therapist help decide what assistive devices are appropriate.¹⁵^–¹⁷ For some patients early use of a functional orthosis such as a wrist-driven flexor hinge splint will advance the rate of rehabilitation. For patients with early but weak recovery of wrist extension, the wrist-driven flexor hinge splint represents an excellent exercise therapy directed towards strengthening wrist extensors so that they may eventually actuate a surgically reconstructed pinch or grip.

Hand or upper extremity surgery is rarely indicated during the initial months of rehabilitation following injury. The patient needs time to experience neurologic, psychologic, and social stability. From a practical standpoint, there are simply too many more important rehabilitation activities going on. On the other hand, a dogmatic philosophy embracing tired dicta such as “never operate on a patient before 12 months” has no basis in science. Some patients are clearly candidates for surgery prior to this calendar date. For example, early surgical intervention to relieve the pathologic effects of a fixed elbow flexion contracture may allow a patient to participate more vigorously in necessary rehabilitation activities.⁶ Early release of a fixed elbow flexion contracture can be done with a simultaneous transfer of the contracted biceps muscle to the triceps. This removes a pathologic or deforming force and reinforces or restores some power to the antagonist. Botox is another important tool in the early rehabilitation armamentarium. It is especially helpful for patients with concomitant brain injury who may not comply with splinting or therapy and have increased tone.

Once the patient has achieved neurological and psychological stability, a formal evaluation to establish the appropriateness of upper extremity surgery can be accomplished by the team. The evaluation should focus on both tangible evidence of recovery by assessing remaining motor and sensory resources and the important intangibles such as motivation and intelligence. There is increasing recognition of the co-occurrence of traumatic brain injury with spinal cord injury and the impact of brain injury on rehabilitation.¹⁸ Cognitive deficits need to be understood before embarking on upper extremity reconstruction given the intensive post-surgical therapy. The initial patient assessment should include an evaluation on how the patient accomplishes tasks of daily living with particular attention to how he or she performs transfers and pushes a wheelchair (Fig. 37.1). Tendon transfers may alter the position of the hand and fingers. After reconstruction wheel chair propulsion and bed transfers must be performed in a safe manner to prevent stretching of the repairs (Fig. 37.2). It is best for patients to learn safe transfer and propulsion techniques before surgery.

Fig. 37.1 Transfers performed on the flattened hand, while stable, will, over time, destroy the collateral ligaments about the thumb and the MP joints. Furthermore, if continued after functional surgery, this posture will stretch-out tenodeses and break down joint fusions. A similar fate awaits the thumb in this patient who uses his thumb to push the “quad-knobs” of the wheelchair. Patients with these postures must be retrained to perform safer transfers and propulsion maneuvers prior to considering surgical reconstruction.

Fig. 37.2 A patient pushing his wheelchair after pinch reconstruction.

The upper limb examination includes assessment of residual motor groups as well as the identification of pathologic conditions such as contracted, painful, or unstable joints. There is also a sensory evaluation, which includes measuring 2-point discrimination in the digits to assess proprioception. The currently used grip patterns are assessed (Fig. 37.3). Occasionally, spinal cord injured patients will have focal areas of severe neuropathic pain that will make the exam painful and potentially limit surgical results.

Fig. 37.3 A patient threading a fork through his fingers to grasp.

The patient’s current functional status is assessed. Is he dependent or independent in bed mobility? How are transfers performed? Does he use a manual or electric wheelchair? What adaptive devices are used for dressing? … grooming? … feeding? If surgery is to be performed, is there sufficient support to get the patient through a period of greater functional dependence or will be the extra burden of care result in the patient’s attendant quitting. For many patients, upper extremity surgery means restriction to an electric-driven chair. Can this be made available? Does the home situation permit the use of an electric wheelchair? Are the controls of the chair mounted on the nonoperated side? The patient’s primary therapist plays the most important role in determining these issues. Preparation before surgery will prevent complications such as pressure sores and social consequences such as divorce.

Finally, the patient’s goals for surgery are reviewed. It is often helpful for a specific task to be identified, e.g., “I want to eat the triple decker sandwich at Joe’s by myself.” This was an achievable goal for this patient. This discussion helps the surgeon understand if the patient has reasonable expectations and can help tailor the procedures.

Treatment/surgical technique

General guidelines for reconstruction

Four surgical procedures are applicable for improving upper limb function in tetraplegia:

1. Arthrodesis: permits stabilization of joints lacking muscle stabilization

2. Tenodesis: performed either to stabilize a joint or more commonly so that another, typically more proximal movement, e.g., wrist extension, will result in the tightening of the tenodesis and movement of a more distally located joint

3. Tendon transfer: the transfer of the power of an expendable muscle-tendon unit under good volitional control to compensate for the absence or ineffectiveness of function of another muscle-tendon unit.

4. Functional electrical stimulation or FES: this technique utilizes the residual contractile properties of upper motor neuron paralyzed muscles when stimulated by an extra neural source. FES allows for more the use of more residual muscles in the reconstructive plan. At this time, FES is not commercially available.

Tendon transfers are the workhorse procedures for reconstruction of the upper extremity in tetraplegia. These techniques have been refined over the last 80 years and several basic principles have evolved. (1) First is correction of any joint contracture. Tendon transfers are often biomechanically disadvantaged and will not be able to overcome a contracted joint. (2) The donor muscle must have adequate strength. Transferred muscles will generally lose a grade of strength after transfer. Therefore it must be strong preoperatively to be able to perform functional tasks postoperatively and should have a MRC >4. (3) The donor muscle must be expendable. (4) Straight line of pull, for the best biomechanical advantage most effective routing of muscle insertion to origin is a straight line. (5) The soft tissue bed must be stable. These surgeries must be performed in a supple bed with adequate skin coverage. Scarred beds will prevent tendon gliding and impair the result. (6) The donor muscle should have adequate excursion to perform the desired function.

For people with tetraplegia, spasticity must also be considered. The donor muscle must have volitional control and not have too much tone. Overall level of spasticity can be improved with physical therapy and medications. A small amount of spasticity and tone is acceptable and sometimes beneficial to reconstructive procedures. The surgeon should assess the level of spasticity and make sure it is optimized before intervention.

The remainder of this chapter is devoted to a discussion of the role of surgery for improving function at the elbow, wrist, and fingers. The challenge of this discussion is that a clear linear treatment algorithm cannot be designed. For these procedures it is critical that each patient, and indeed each upper extremity, be evaluated and then each treatment plan individualized.

For high cervical spinal cord injuries, there are no expendable muscles available for transfer in the arm. For patients with lower injuries such as a C7 injury, many potentially expendable, and thus transferable, muscles of grade 4 or 5 power exist. Thus reconstructive possibilities range from procedures to simplify the mechanics of the hand, such as arthrodesing a wrist joint to eliminate the need for an external stabilizing orthosis, to complex multi-staged procedurals involving many muscle-tendon transfers. The choice of procedure depends primarily on the residual resources and, secondly, on the many intangibles such as patient desires, motivation and support. The surgical techniques used in tetraplegia are the same procedures as reconstructions after peripheral nerve injuries, but the difference between these procedures is the preoperative preparation and matching the patient to the correct procedure. A cautious approach while one gains experience pays great dividends in terms of obtaining the acceptance of team members and patients that surgery can promote greater independence for these patients. A poor outcome early in the team’s experience creates a tremendous hurdle.

Surgical reconstruction

Elbow extension

Erik Moberg brought to our attention the importance of active elbow extension for the spinal cord injured patient. The individual who uses a wheelchair depends upon good shoulder and elbow power and stabilization to push a manual wheelchair, transfer from bed to chair, and to perform pressure releases to prevent pressure sores. For the person with tetraplegia lack of a functional elbow extension results in a much-reduced functional environment. If surgery can increase the reachable space by an additional twelve inches there is then 800% more space the hand can reach.

Without active elbow extension, the tetraplegic’s hands frequently fall into his face when lying supine, which makes eating and daily hygiene challenging (Fig. 37.4). One cannot push a manual wheelchair up any incline without triceps function. Even as simple a task as turning on a room light switch may be impossible without active elbow extension. There are two surgical procedures advocated for restoring active elbow extension, biceps to triceps and deltoid to triceps transfer.

Fig. 37.4 Postoperative elbow extension allowing for stabilization of the arm to assist with combing the hair

Biceps to triceps transfer

This procedure ¹⁹^–²¹ has become increasingly popular.²² It is the procedure of choice when there is a pre-existing flexion contracture of the elbow greater than 45°. In this case, the biceps is usually a deforming force that must be addressed. The advantages of biceps to triceps transfer include no need for an interposition graft and only one tendon repair site. Disadvantages include a more challenging rehabilitation program and the potential for loss of elbow flexion strength.

Surgical technique

The biceps tendon is detached from its insertion on the greater tuberosity of the radius, the muscle-tendon unit routed either medially ²³ or laterally,^24,²⁵ and the tendon attached to the triceps aponeurosis or directly into the olecranon.

The incisions that are employed depend in large measure on whether a wide exposure to the anterior aspect of the elbow joint is needed to allow adequate release of contracture. The distal extent of the incision should allow complete dissection of the tendon of the biceps so that it can be detached as close to its point of insertion on the bicipital tuberosity of the radius (Fig. 37.5A).

Fig. 37.5 Biceps to triceps transfer by the medial route (A–D).

(Redrawn from Hentz V, Leclercq C. Surgical Rehabilitation of the Upper Limb in Tetraplegia. London: Harcourt Health Sciences; 2002, with permission.)

The incision is carried through the subcutaneous tissue, protecting the large tributaries of the basilic and cephalic veins. The soft tissues overlying the lacertus fibrosis are elevated and the lacertus is either divided off the primary tendon or dissected distally as far as possible to provide another point of fixation to the triceps (Fig. 37.5B).

The primary tendon of the biceps is dissected to its point of insertion on the radius. Flexing the elbow and supinating the forearm assists in this exposure. The tendon is sectioned as far distally as possible. The biceps muscle is dissected proximally from within its dense investing fascia, the dissection proceeding proximally until the cutaneous portion of the musculocutaneous nerve is identified as it courses between the overlying biceps and the deeper brachialis muscle. This nerve is protected while dissection of the biceps proceeds proximally until the most distal motor branches coming from the musculocutaneous nerve are visualized.

Both medial and lateral routing of the transfer have been described. Since the ulnar nerve is typically non-functional in this population, we have preferred to route the biceps medially. It is necessary to dissect widely the arcade of Struthers and all other fascial communications about the medial intermuscular septum. One must be concerned about compression of the radial nerve when the lateral route is chosen.

A second incision located posteromedially is made in order to expose the medial aspect of the triceps insertion. Through this incision, the medial border of the triceps is elevated and dissected to its insertion on the olecranon. The biceps muscle and tendon are then passed from the anterior to the posterior incision through the widely dissected subcutaneous tunnel (Fig. 37.5C). The anterior incision may be closed at this point.

The biceps tendon typically just reaches the tip of the olecranon but there is infrequently sufficient tendon length to permit a strong attachment into the olecranon. Instead, the tendon of the biceps is woven into the medial border of the triceps tendon and anchored in multiple locations with stout sutures (Fig. 37.5D). We have judged that the proper tension is achieved when the biceps is pulled distally enough to permit the end of the tendon to touch the olecranon with the elbow in about 20° of flexion. Once the tendon-to-tendon junctures are made, the elbow is fully extended to relax the site of approximation.

Postoperative care

Regardless of the technique chosen, the elbow is immobilized in full extension using a light plaster or fiberglass cylinder cast for 3.5 weeks. An overhead, chair-mounted sling is fitted to their wheelchair and is used whenever the patient is in the wheelchair and until the cast is removed.

The initial cast is left undisturbed for 3.5 weeks if the elbow had essentially normal passive extension preoperatively. If the elbow had a preoperative flexion contracture between 15° and 30°, the elbow is extended as much as possible at the time of surgery and casted in that position. This cast is removed between 10 and 14 days postoperatively. Great care must be taken to keep the elbow extended during this maneuver. Typically, the elbow can then be further extended at this time by slow stretch and the arm is recasted, now typically in near full or even full extension. After removal of the cast, the elbow is exercised for several additional weeks by allowing progressively greater elbow flexion in a specially designed flexion-stop brace (Fig. 37.6). Although the biceps seems to be an antagonist to elbow extension, by teaching the patient to conjointly supinate the forearm and extend the elbow, the patient can be reeducated to use the supinator function of the biceps to extend the elbow. Electrical stimulation and biofeedback therapy has been used on occasion with improved results. Some months of cautious use are necessary to prevent overstretching of the transfer and many months pass before maximal strength is obtained.

Fig. 37.6 Hinged orthosis to protect the repair across the elbow. The degree of flexion is gradually flexed over time.

Deltoid to triceps transfer ²⁶

Surgical technique

Hints and tips

1. Detach the deltoid from the humerus with as much fascia and fibrous insertion as possible, including some of the fascial origin of the brachialis muscle.

2. Attach the deltoid to the triceps at maximum tension with the shoulder abducted 30° and the elbow flexed at 30°

3. Cast elbow in full extension and keep the arm abducted at the shoulder during healing.

The surgical landmarks (Fig. 37.7A) at the level of the shoulder include the tip of the acromion superiorly, the interval between the posterior margin of the deltoid and the triceps muscle posteriorly, and the estimated point of insertion of the deltoid on the humerus. The landmark at the level of the elbow is the tip of the olecranon. The surgeon should keep in mind the neurovascular anatomy of the region including the course of the axillary nerve and the circumflex humeral artery and the radial nerve and its relationship to the insertion of the deltoid (Fig. 37.7B).

Fig. 37.7 The author’s preferred technique for deltoid to triceps transfer (A–H).

(Redrawn after Hentz V, Leclercq C. Surgical Rehabilitation of the Upper Limb in Tetraplegia. London: Harcourt Health Sciences; 2002, with permission.)

The upper incision is centered half way between the mid-axial line of the humerus and the posterior margin of the deltoid (Fig. 37.7A). The skin incision is carried to the level of the muscle fascia and the skin and subcutaneous tissues are elevated anteriorly to just past the mid-axial line of the humerus. Posteriorly, the skin flap is elevated to the confluence of deltoid and the long head of the triceps (Fig. 37.7C). The plane between these two muscles is developed by sharp or finger dissection. As the finger strikes the humerus, the fingertip tip can be insinuated upward through the fibers of the deltoid, separating the muscle into relatively equal anterior and posterior halves.

Detaching the insertion of the posterior half of the muscle from its point of insertion onto the humerus is done by sharply incising a rectangle of periosteum at the point of attachment and elevating the periosteum and the fibers of attachment off the humerus. We include as much fascia and fibrous insertion as possible, including some of the fascial origin of the brachialis muscle. The radial nerve will be emerging from behind the humerus several centimeters distal to this point. Injury to this nerve has been reported as a rare but devastating complication of this procedure.

A suture is placed in the fibrous origin of the posterior half of the deltoid muscle and the dissection is carried superiorly until the branches of the axillary nerve are visualized (Fig. 37.7D). The superior dissection should stop at this point.

Several methods have been proposed to attach the posterior deltoid to the triceps or olecranon including:

• Autogenous tendons such as toe extensors,²⁷ tibialis anterior tendon,⁹ or extensor carpi ulnaris²⁸

• A turned up strip of the central part of the triceps tendon with synthetic reinforcement ²⁹

• Bone to bone attachments ³⁰

• Various synthetic materials.³¹

We prefer the patient’s own fascia lata, especially in the patient whose triceps tendon is relatively short or insubstantial.³²

The fascia is harvested through several transverse incisions placed over the iliotibial band (Fig. 37.7E). The ideal width is about 2.5 cm. The fascia lata is encircled about the fibrous insertion of the deltoid using mattress sutures of nonabsorbable braided suture (Fig. 37.7F), tubed over its remaining length and tunneled subcutaneously to the olecranon.

The olecranon is exposed just distal to the insertion of the triceps. The triceps tendon is split longitudinally to further expose the tip of the olecranon and a 5 mm drill bit is used to create an oblique tunnel through the olecranon (Fig. 37.7G). A Bunnell tendon-stripper is a useful instrument to “polish” this channel so that the tubed fascia lata can be passed smoothly in a proximal to distal direction (Fig. 37.7H).³³ The fascia lata is passed into the distal exposure, separated into two tails and the tails are passed through the bone channel.

The shoulder is abducted about 30° and the elbow is flexed about 30°. The two fascia lata tails are then pulled to maximally tense the transfer and these tails are turned proximally and woven into the fascia lata tube and anchored with non-absorbable sutures. Once suturing is complete, the fascial tube should be under moderate but definite tension. The wounds are closed and a cylinder cast is placed as is described in the biceps to triceps transfer with the elbow fully extended.