Tetraplegia

Pathogenesis of the Injured Spinal Cord

The cervical spinal cord contains eight cervical segments encased in the seven cervical vertebrae. The bone and ligamentous structure of the cervical spine allows a wide range of motion, thus exposing the cervical spinal cord to increased risk of injury. Injury occurs most commonly through a flexion deformity with bone or disk compression of the cord after fracture or dislocation or through traction on the cord with translation due to spine instability ( Fig. 33.1 ). Over days and weeks, acute hemorrhage and edema subside, followed by local reparation and finally scar formation.

Following trauma to the spinal cord, the cord is divided into three basic regions: the supralesional segment, the injured metamere, and the infralesional segment ( Fig. 33.2 ). The supralesional segment refers to the region of the spinal cord cephalad to the site of injury, which retains normal function. The infralesional segment refers to the spinal cord below the region of trauma. The infralesional segment consists of normal spinal cord and normal associated peripheral nerves that have been disconnected from descending cortical control either completely (no intentional movement realized) or incompletely (some degradation of control, typically with substantial spasticity).

The injured metamere is the region of the cord that suffered the direct trauma. This region can be discrete and well localized, as may occur from a local disk herniation. Alternatively, the region can be lengthy and involve multiple segments, as may occur following a fracture-subluxation of the vertebrae or gunshot wound. This differentiation is important because the most vulnerable portion of the spinal cord is the central gray matter—the home of the cell bodies of the alpha motor neurons. These cell bodies will be lost at the site of injured metamere. Wallerian degeneration occurs and proceeds in a distal direction down the peripheral nerve. Over time, the associated muscles undergo severe atrophy and fatty degeneration. ^, Similar to a peripheral nerve injury, the associated muscles can only be effectively recovered in the acute period following the injury. In patients who are candidates for nerve transfer, surgery should be undertaken early to optimize the results of the reconstruction. The more time that transpires without innervation in these affected muscles, the less effectively they can recover. After a year from injury, the results following nerve surgery are compromised. After 2 years, useful recovery is not expected. Thus earlier surgical intervention is recommended.

The region of central gray matter destruction may extend partially into an adjacent region, which may not be clinically apparent via denervation atrophy. For example, the cephalad extent can degrade the innervation of the supralesional segment, such that the axon supply to a healthy and normal muscle is reduced. These muscles often have good active control and appear normal. This potential axon depletion must be understood when contemplating nerve transfer surgery and will be discussed in more detail later.

Considering Spontaneous Recovery

Within the first year following the injury, there is some potential for spontaneous recovery. Surgery must avoid disrupting any natural recovery. There are two types of spontaneous recovery, American Spinal Injury Association (ASIA) grade conversion ( Table 33.1 ) and recovering a cord level or more. Regarding conversion to a different ASIA grade, patients with more favorable injuries have more positive rates of spontaneous recovery. For instance, only about 10% to 15% of patients assessed as ASIA A will convert to ASIA B with an even smaller percentage recovering to ASIA C or D. In contrast, these conversion rates are higher for patients with ASIA B with up to 40% recovering to ASIA C or D. Accordingly, up to 60% to 80% of patients initially categorized as ASIA C will spontaneously convert to ASIA D. In about 80% of patients who demonstrate an improvement in ASIA grade, this recovery will occur within the first 3 months, according to data from the European Multicenter Spinal Cord Injury (EMSCI) Database. Fewer than 20% of patients who improve in ASIA grade first show delayed signs of recovery between 6 and 12 months. After 1 year, this figure drops to only 5%.

In addition to ASIA grade conversion, persons with tetraplegia can also recover segment levels distal to their site of injury. This recovery can have a major impact on upper extremity function. For example, the difference between a C4 and C5 injury or a C5 and C6 injury translates into tremendous gains in independence. From 57% to 72% of patients with ASIA A injuries will experience recovery of at least one adjacent motor level. Within this subset, 30% recovered two levels. In the setting of complete spinal cord injuries, some authors have described the concept of the “zone of partial preservation,” which designates muscle groups that are partially innervated after injury. Partially innervated muscle groups that possess 1-2/5 British Medical Research Council (MRC) grade power ( Table 33.2 ) or greater are significantly more likely to recover to 3/5 strength versus muscles groups that are initially 0/5 grade. ^,

As discussed above, the majority of patients even with sensorimotor complete injuries (ASIA A) will regain one or two motor levels within the first year after injury. Recovery occurs most frequently within the first 3 months. By 9 months, the majority of patients have experienced their maximum spontaneous recovery.

The strength of muscles at the level of injury may also improve over time, most commonly within a year of injury. Ditunno and colleagues and Waters and associates reported upper limb strength recovery rates using manual muscle testing and the MRC grading system (see Table 33.2 ). One-third of muscles classified as grade 0 at 1 month after injury improved to grade 3 at 4 to 6 months after injury; improvement was documented in some cases up to 24 months after injury. All upper limb muscles with an initial strength of grade 1 improved to at least grade 3 by 1 year after injury, with the exception of the triceps. If a muscle’s strength was grade 2 or better at 1 month after injury, the median time for full recovery was 6 months.

Based upon the available evidence, we defer surgery until 6 to 9 months following injury. At that time, patients that fail to demonstrate improvement in ASIA grades or recovery of additional segment levels distal to their site of injury are encouraged to proceed with surgery.

Referral for Upper Limb Reconstruction

The referral process for persons with spinal cord injury remains disorganized and underutilized. Curtin and colleagues have shown that approximately 65% of the 5000 cervical spine injures per year would benefit from upper limb reconstruction to improve function and increase independence. Despite the potential benefits, less than 500 surgeries are performed annually to improve upper limb function. This disconnect is multifactorial with responsibility levied on physiatrists, surgeons, and institutions.

Published reports of tendon transfers for persons with spinal cord injury have shown improvement in quality of life and overall function. ^, Despite this evidence, many physicians and even spinal cord rehabilitation facilities remain wary or are unaware of the potential benefits. Many patients that would benefit from surgical reconstruction are never referred for surgical evaluation. With the advent of nerve transfers, this problem will escalate unless knowledge dispersion increases across all subspecialties that manage persons with spinal cord injury. A person with spinal cord injury can typically gain one cervical spinal level of function through tendon transfers. Augmenting the current tendon transfer paradigm with nerve transfers can restore two cervical spinal cord levels of function. However, nerve transfers require a viable muscle target for reinnervation, and irreversible motor endplate demise occurs as early as 18 months from injury. Therefore most nerve transfers have limited success after 12 months from injury. This window of opportunity highlights the time sensitivity and necessity of prompt referral for upper limb reconstruction.

Preoperative Evaluation

The reconstructive surgeon is less concerned with the specific level of cervical injury than with the remaining strength of each muscle in the upper limb. Classically, tetraplegic patients have been classified by the injured cervical spine segment of C1-C7. Previously, it was assumed that the level of paralysis and sensory loss coincided with the bony injury, producing a precise transverse spinal cord lesion. Careful examination of tetraplegic patients has shown, however, little relationship between the level of the skeletal lesion and the spinal cord lesion. In addition, lesions may be asymmetric with unusual patterns of spared sensory or motor function. A classification for spinal cord injury commonly used by surgeons other than hand surgeons is the ASIA classification (see Table 33.1 ). This classification is based on intact muscle groups.

The classification used in this chapter was developed by an international group of hand surgeons in 1978 in Edinburgh ^, and modified in 1984 at Giens, France. The International Classification for Surgery of the Hand in Tetraplegia (ICSHT) grades the level of the spinal cord injury based on the number of muscles with grade 4 strength below the elbow and includes ICSHT levels 0 to 9 ( Table 33.3 ). The ICSHT level characterizes the most common patterns of presentation, based on the number of functional muscles below the elbow. The majority of persons with complete spinal cord injury will fall into ICSHT motor groups 2 and 3.

Another aspect of patient evaluation includes assessment of the general suitability for surgery. The assessment is based on various factors including age, occupation, level of education, learning capacity, motivation, economic support, family support, and agency support. The patient must have a clear understanding of what can and cannot be accomplished with surgery.

Physical Examination

The examination begins with a thorough history of the injury and treatment to date. Subsequently, a meticulous physical examination is performed, including sensory and motor testing to establish the patient’s group (ICSHT level 0 to 9). Manual muscle testing (see Table 33.2 ) is performed on all muscle groups in the upper extremity. The surgeon can make a working list of tendons that are available for transfer (grade 4 strength or higher and expendable) and muscles that are paralyzed (grade 1 strength or lower). Once the muscles with grade 4 strength have been identified, the patient is assigned a group number (see Table 33.3 ). For example, a patient with grade 4 strength of the brachioradialis (BR), both radial wrist extensors, the pronator teres (PT), and the flexor carpi radialis (FCR) would be classified as a group 5 patient. One of the difficulties in physical examination is distinguishing between group 2 and group 3 injuries. In group 2 patients, only the extensor carpi radialis longus (ECRL) has a grade 4 or higher strength, and physical examination reveals substantial radial deviation of the wrist with resisted wrist extension. In group 3 patients, both the ECRL and the extensor carpi radialis brevis (ECRB) have strength of grade 4 or higher. In a group 3 patient, the wrist extends with less radial deviation and often grade 1 to 3 strength is present in the PT, the next most caudal muscle. In thinner patients, the ECRL, a flat muscle, and the ECRB, a more bulbous muscle, can be palpated while muscle strength is being tested ( Fig. 33.3 ).

In addition to manual muscle testing, the surgeon must also examine the passive range of motion to evaluate joint and muscle contractures along with the resting posture of the hand. The examiner can induce a tenodesis effect by passively flexing and extending the wrist while observing passive myostatic tensioning of the digital extensors and digital flexors, respectively. The hand must have passive mobility and tenodesis to achieve success. For example, if the thumb rests in a fully supinated position and lacks any tenodesis pinch during wrist extension, tendon transfers for pinch will be ineffective without skeletal stabilization (carpometacarpal [CMC] fusion) in a key pinch position.

The management of the wrist and hand in tetraplegia follows the concepts of “hierarchy of hand function” or the “reconstruction ladder.” The primary fundamental movement is wrist extension, which yields tenodesis for grip as the fingers flex into the palm and tenodesis for lateral pinch as the thumb adducts against the index finger. Wrist extension also aligns the finger flexors along Blix’s length-tension curve for maximum active grip. The second most essential movement is lateral pinch, which is necessary to perform numerous ADLs. Most daily activities are accomplished with lateral pinch, such as holding an object, turning a key, or using a fork ( Fig. 33.4 ). The third essential motion is grasp, which allows the holding of objects ( Fig. 33.5 ). The fourth and last movement is digital opening for object acquisition. The reason to place this function lowest on the ladder is that wrist flexion yields passive digital opening, which is often adequate for object procurement. In addition, synchronous digital opening is difficult to achieve via surgery as metacarpophalangeal (MCP) joint extension is mainly an extrinsic function (extensor digitorum communis, extensor indicis proprius, and extensor digiti quinti) and interphalangeal (IP) joint extension is primarily an intrinsic function (interossei and lumbricals). The only way the extrinsic system can elicit IP joint extension is by limiting MCP joint extension (e.g., Zancolli tenodesis of the flexor digitorum superficialis [FDS] or House intrinsic tenodesis). The Zancolli tenodesis of the FDS procedure can cause problems such as limiting flexor digitorum profundus excursion and/or attenuating over time. The House intrinsic tenodesis is difficult to set the appropriate graft tension. Restoring both MCP and IP movements by tendon transfer(s) remains a daunting task replete with complications. A lumbrical bar fabricated by an experienced therapist may be a simpler solution to limit MCP joint extension.

The next step is to determine the patient’s needs and match the needs with the muscles available for transfer. For example, in a group 4 patient, the BR is available because the patient has the biceps and brachialis for elbow flexion (and, therefore, no function will be lost with the transfer); the ECRL is also available because the patient has the ECRB for wrist extension. The PT can also be used for transfer, but this could result in diminished pronator power and loss of strength for manual wheelchair function. To complete the assessment, the muscles available for transfer (BR, ECRL) are matched with the needed functions according hierarchy of hand function or the “reconstruction ladder” combined with other surgical options such as arthrodesis and tenodesis. In a group 4 patient, pinch and grasp are deemed most important, as these patients have active wrist extension. Thus the BR and ECRL are selected for thumb pinch and finger flexion, respectively. The BR will be transferred to the flexor pollicis longus (FPL) because it has (and needs) less excursion. The ECRL will be transferred to the flexor digitorum profundus (FDP) tendons, which is synergistic and provides greater excursion. Surgical adjuncts to be considered include optimizing the thumb position for key pinch with a CMC fusion and augmenting digital extension for object acquisition via extensor pollicis longus (EPL) and extensor digitorum communis (EDC) tenodesis. If necessary, intrinsic reconstruction can be added during a second surgery. By evaluating what the patient has, what the patient needs, and what is available, the surgeon can determine the optimal combination of tendon transfers and adjunctive procedures to restore function (nerve transfers will be discussed later).

Diagnostic Imaging

At the time of the acute spinal cord injury, advanced diagnostic imaging is performed to determine the extent of spinal cord and skeletal injury (see Fig. 33.1 ). Subsequent imaging is performed to assess for spinal stability. Prior to upper extremity surgery, flexion and extension lateral x-rays are necessary to ensure stability ( Fig. 33.6 ). Advanced imaging is not routinely performed.

Tendon Transfer

Tendon transfers are preferred over tenodesis or arthrodesis because these restore active control and strength. However, the primary problem after spinal cord injury is a paucity of adequate donor muscles available for transfer. It is critical to ensure that sacrifice of a potential donor muscle for transfer will not create another functional deficit. The available muscles are prioritized first for wrist extension, then for pinch, then for grasp, and finally for release functions. Tendon transfer principles, including donor availability, donor strength, amplitude of excursion, synergism, passive mobility of recipient joints, and condition of the soft tissue bed, are prerequisites. When tendon transfer options are exhausted, additional hand functions may be achieved through tenodesis and/or arthrodesis.

Tenodesis

Tenodesis is defined as the movement of one joint produced by the motion of an adjacent (usually proximal) joint. For instance, passive extension and flexion of the wrist prompts digital flexion and extension, respectively. Although the finger and thumb muscles are paralyzed, there is sufficient remaining myostatic tension to induce reciprocal action of the digital flexor and extensor tendons that cross the wrist joint. Spinal cord injury patients learn to use the tenodesis effect naturally and commonly have functional but very weak pinch or grasp owing to the tenodesis effect alone. The tenodesis effect can be enhanced surgically without the need to transfer an active muscle. Passive tenodesis procedures anchor the paralyzed tendon proximal to the wrist joint to decrease effective tendon excursion and thus increase digital movement with active wrist movement. Common tenodesis techniques include anchoring the finger flexors and extensors for grasp and release, respectively.

Arthrodesis

Thumb CMC joint arthrodesis is useful to stabilize this multiarticular joint for pinch. The index finger proximal IP (PIP) joint can undergo arthrodesis to stabilize the finger as a firm post for pinch. The wrist is never fused because the tenodesis effect would be lost. Surgical techniques for arthrodesis are no different in the paralytic hand. When possible, rigid fixation is preferred to allow earlier weight bearing and expedient mobilization.

Nerve Transfer

Nerve transfers have supplemented and even supplanted the use of tendon transfers in some clinical scenarios. The ICSHT is applicable to nerve transfer with important considerations. Nerve transfers will be discussed in detail following the section on tendon transfers. Tendon transfer reconstruction is based on the patient’s international classification group (see Table 33.3 ). Elbow procedures are discussed first, followed by procedures for grasp, pinch, and release.

Elbow Extension Tendon Transfer

Most persons with cervical spine injury lack triceps function and elbow extension. Restoration of elbow extension carries a high priority. Active elbow extension assists the patient in reaching objects above the shoulder level, improves driving ability, aids in wheelchair propulsion, permits pressure relief, and facilitates independent transfer. Additionally, active elbow extension provides an antagonist to elbow flexion, which facilitates improved function through tenodesis after hand reconstructions that use the BR as a tendon transfer. Pinch strength has been shown by Brys and Waters to improve from 0.15 to 3.9 pounds in wrist extension in patients after elbow extension tendon transfers that improve elbow extension strength. Two options exist for tendon transfer: deltoid to triceps transfer and biceps to triceps transfer. ^{, ,}

The biceps and the deltoid are innervated from the spinal cord at a higher level than the triceps. The posterior deltoid to triceps transfer has been used extensively over the past 30 years, but more recently, the biceps to triceps transfer has been used more frequently.

Biceps to Triceps Tendon Transfer ( Video 33.1 )

The biceps to triceps tendon transfer is our preferred method for establishing elbow extension ( Fig. 33.8 ). The biceps is used as the donor muscle. To ensure that function will not be lost with transfer of the tendon, the strength of the brachialis as an elbow flexor and of the supinator as a forearm supinator must be verified before transfer. Manual muscle testing for elbow flexion is performed, attempting to isolate the brachialis by supinating the forearm, which relaxes the biceps. This can be verified by palpating the groove between the anterior tubular biceps and the flatter brachialis that resides posterior to differentially test strength. In reviewing the segmental innervations of the upper limb from the spinal cord (see Fig. 33.7 ), note that the biceps, brachialis, and supinator are all innervated at about the same level (C5-C6). If the patient has strong wrist extension, the spinal cord lesion should be below C6, sparing the biceps, brachialis, supinator, and wrist extensors, but above the innervation of the paralyzed triceps. Such findings on clinical examination verify that transfer of the biceps will not lead to a functional loss. Electromyography is not part of the routine evaluation. If there is any doubt about the strength of the brachialis or supinator, the biceps muscle can be injected with bupivacaine, which induces temporary paralysis. Subsequently, the strength of the brachialis and supinator can be assessed.

The biceps to triceps tendon transfer can be performed using a medial ^, or a lateral routing technique. The lateral technique was first described by Friedenberg in 1954 and later reported by Zancolli. ^, No loss of active elbow flexion was noted, although flexor strength was diminished by 24%. In 1988 Ejeskär reported his results using the lateral routing technique in five patients, including the first complication of radial nerve palsy. Injury to the radial nerve and medial routing is strongly preferred.

The procedure is performed with the patient supine, a roll under the operative shoulder blade, and the limb draped free with a sterile tourniquet high on the arm. The incision extends from the midhumerus on the medial side, transversely across the antecubital crease, and courses distally, centered over the biceps insertion on the radial tuberosity. The lateral antebrachial cutaneous nerve is identified and protected as the biceps tendon is dissected free from its medial and lateral fascial attachments in the arm and then sharply released from its insertion on the bicipital tuberosity. The lacertus fibrosus is freed from the forearm fascia during the dissection and can be preserved as a second tail of the biceps tendon for subsequent weaving. The muscle is raised in a proximal direction, with care taken to preserve the musculocutaneous nerve running on its undersurface and along the brachialis muscle.

A second (posterior) incision is performed over the distal one-third of the triceps tendon, passing lateral to the olecranon to avoid subsequent olecranon pressure ulceration and allowing an adequate skin bridge with the medial incision. A subcutaneous tunnel is made around the medial elbow from the anterior wound to the posterior wound, creating a line of pull that is straight and free for medial rerouting of the biceps ( Fig. 33.9A ). The medial intermuscular septum may need to be partially resected, and care is taken to protect the neighboring ulnar nerve. The biceps tendon is passed from the anterior wound into the posterior wound. The tendon can be routed superficial or deep to the ulnar nerve. We prefer deep to avoid iatrogenic compression of the ulnar nerve, particularly if there are future advances in neuroregeneration (see Fig. 33.9B ). A No. 5 nonabsorbable grasping suture is placed into the end of the biceps tendon.

The triceps tendon is split and the tip of the olecranon is exposed. A large-bore blind bone tunnel is made in the olecranon for acceptance of the biceps tendon. The tendon is passed through the medial leaflet of the triceps tendon in preparation of docking into the bone tunnel (see Fig. 33.9C ). The tendon is docked using two posterior unicortical holes and suture retrievers (Suture retriever, Smith Nephew, Andover, MA) (see Fig. 33.9D ). The elbow is placed in full extension and the two ends are drawn into the bone tunnel using suture retrievers (see Fig. 33.9E ). The sutures are tied over the posterior olecranon cortex. Additional suturing is performed during closure of the triceps split with incorporation of the biceps tendon. The lacertus fibrosus can be interwoven through the biceps to triceps weaves to further secure the tendon weave. Following closure, a well-padded long-arm cast is applied with the elbow in extension (see Fig. 33.9F ). The wrist is included within the cast and the hand position depends on concomitant procedures performed for hand function.

Tendon rehabilitation requires supervised therapy for months. The biceps to triceps can be mobilized early (7 to 10 days) or delayed (3 weeks) depending on the patient’s age, patient’s compliance, and the strength of the tendon transfer repair. The rehabilitation is divided into three phases: early mobilization, mobilization, and strengthening/functional retraining. Mobilization is initiated in gravity-eliminated plane within a limited arc of flexion. Flexion is progressively increased 15 degrees per week as long as no extension lag develops. Strengthening and wheelchair propulsion are prohibited until 12 weeks from surgery. Transfers and weight shifts are initiated 16 weeks from surgery.

The strength of the biceps to triceps transfer continues to improve for at least a year, resulting in substantial improvements in performing ADLs. Antigravity elbow extension is obtainable in the vast majority of cases ( Fig. 33.10 ; Video 33.2 ). Published series have reported functional improvements for overhead, reaching, and driving activities. ^{, , , ,} No clinical loss of active flexion has been reported, although flexor strength was diminished by 24% in one series. Mulcahey and coworkers published a randomized prospective comparison of posterior deltoid to biceps transfer versus biceps to triceps with medial routing transfer. These authors reported that at 2 years, seven of eight arms treated with biceps to triceps transfer had antigravity use of the arm, whereas only one of eight arms treated with posterior deltoid to triceps transfer had antigravity use of the arm.

Posterior Deltoid to Triceps Tendon Transfer

The posterior deltoid must have adequate strength to motor elbow extension. Shoulder extension and palpation best assesses posterior deltoid strength and turgor. The examination can be performed with the patient seated, although placing the patient prone provides a more reliable assessment. Similar to biceps to triceps transfer, a supple elbow with near complete range of motion is also necessary. Patients with an elbow contracture require resolution of the contracture prior to surgery.

The posterior deltoid to triceps transfer uses the posterior third and the posterior half of the middle third of the deltoid muscle as a donor to provide active elbow extension ( Fig. 33.11 ). An interposition tendon graft is used, and the triceps tendon serves as the insertion.

Prior to prepping and draping, Marcaine with epinephrine is instilled in the planned incision sites. The upper extremity and hemithorax are then prepped and draped in usual sterile fashion. A gently curved incision is made over the deltoid muscle ( Fig. 33.12A ). Skin flaps are elevated. The axillary nerve is identified entering the deltoid muscle (see Fig. 33.12B ). The posterior half of the deltoid is selected for transfer (see Fig. 33.12C ). A periosteal sleeve is elevated with the posterior deltoid. Proximal dissection is performed to improve the excursion and line of pull.

A distal incision is made over the distal third of the triceps tendon. The triceps’ tendon is identified. The ulnar nerve is isolated and retracted out of harm’s way. A subcutaneous tunnel is then created between these two incisions using sequential hemostats (see Fig. 33.12D ). An allograft is favored to bridge the distance between the deltoid muscle and triceps’ tendon. The allograft is thawed and the proximal end is sutured to the posterior deltoid and underlying periosteum (see Fig. 33.12E ). The remaining tendon is then passed through the subcutaneous tunnel to the distal incision (see Fig. 33.12F ). The elbow is placed in full extension and the allograft woven into the triceps tendon and/or bone for additional augmentation (see Fig. 33.12G ).

Several alternatives exist for the interposition graft. Moberg originally used toe extensors from the second, third, and fourth toes to allow at least three weaves at each attachment site. Alternative graft materials have included fascia lata, tibialis anterior, ^, and extensor carpi ulnaris (ECU) Alternatively, Castro-Sierra and Lopez-Pita used the central one-third of the triceps. In this method, a 1-cm strip from the central one-third of the triceps is harvested from its insertion in a retrograde manner (proximally based), mobilizing it sufficiently to graft back to the distal end of the posterior deltoid. Reflecting the central third of the triceps with a bone block and internally fixing this to a bone block from the deltoid insertion has also been described.

After the interpositional graft has been placed, the transfer is sewn into place and tensioned with the shoulder in 30 to 40 degrees of abduction and no forward flexion so that the elbow can flex to 60 degrees with moderate tension. Most commonly, a well-padded long-arm cast is applied to hold the elbow in about 10 degrees of flexion. Forward flexion and shoulder adduction are avoided during the 6 weeks of cast immobilization. Gentle active exercises are performed to slowly gain elbow flexion for the next 3 months with a rate of 5 to 10 degrees of increased flexion per week.

Posterior deltoid to triceps transfers are compromised by the prolonged shoulder and elbow immobilization required postoperatively, as well as tendon graft elongation over time. Elongation of the tendon graft leads to decreased strength over time. Fridén and colleagues used intraoperative metal markers at the ends of the tendon grafts and measured an average of 2.3 cm of elongation after 2 years. They changed their postoperative regimen to include longer elbow extension immobilization and increased shoulder abduction. Follow-up of five patients using this regimen using the same markers averaged 0.8 cm.

Biceps Rerouting Procedure

The biceps is rerouted from a supinator moment arm that wraps counterclockwise around the proximal radius to a pronator moment arm by wrapping the tendon clockwise around the proximal radius ( Fig. 33.14 ). This procedure can be done in isolation or in combination with one of the hand reconstructive procedures listed below. Indications for surgery are passive mobility of the forearm into pronation, without active pronation, as well as a biceps tendon of grade 5 strength that is a deforming force as a supinator leading to dysfunctional supination posturing. The biceps needs to be available for transfer, but not for transfer to the triceps to provide elbow extension strength.

The patient is placed supine on the operating room table and the entire extremity is prepped and draped. A sterile circular tourniquet that exsanguinates during application is applied (HemaClear, OHK Medical Devises, Grandville, MI). An S-shaped incision is made along the medial arm, across the antecubital fossa, and over the BR muscle ( Fig. 33.15A ). The lateral antebrachial cutaneous nerve is identified and protected lateral to the biceps tendon (see Fig. 33.15B ). The biceps tendon is traced to its insertion into the radial tuberosity (see Fig. 33.15C ). There are large crossing veins that require ligation. The lacertus fibrosis is incised from the biceps tendon protecting the underlying neurovascular structures. The entire length of the biceps tendon is isolated. A long Z-plasty is performed leaving one limb left attached to the radius and the other limb attached to the muscle (see Fig. 33.15D ). The limb attached to the radius is rerouted around the radius through the interosseous space to yield a pronation force. A curved clamp, such as a Castaneda pediatric clamp (Pilling Surgical, NC), facilitates tendon passage (see Fig. 33.15E ). The posterior interosseous nerve must be protected to prevent iatrogenic injury.

The elbow is positioned in 90-degrees of flexion with the forearm in pronation. The rerouted distal tendon is woven back through the proximal tendon that remained attached to the biceps muscle (see Fig. 33.15F ). The subcutaneous tissue and skin are closed in routine fashion. A long-arm cast is applied with the elbow in 90-degrees of flexion and the forearm in pronation for 5 weeks.