➢ Spastic deformities of the shoulder and elbow are often seen after injury to the upper motor neuron system.
➢ Radiographs can be used to rule out any osseous abnormalities.
➢ The combination of dynamic poly-electromyographic analysis and selective neuromuscular blockade can help to delineate the pattern of motor function.
➢ When the appropriate treatment strategy is selected, the spastic shoulder and elbow can be successfully treated with tendon releases or fractional tendon lengthenings.
Upper Motor Neuron Syndrome
Upper extremity deformities and dysfunction are often the result of injury to the central nervous system. Upper motor neuron syndrome is a condition that arises as a result of the disruption of the upper motor neuron inhibitory pathways that frequently occurs in association with conditions such as traumatic brain injury, spinal cord injury, cerebral palsy, and cerebrovascular accident1. Damage to these pathways often leads to the constellation of symptoms that characterize this syndrome. Most notably, these symptoms include muscle weakness and diminished endurance as well as symptoms of hypertonicity, such as spasticity (muscle activation with a quick-stretch stimulus), rigidity (exaggerated response with a slow-stretch stimulus), dyssynergy or spastic co-contraction (antagonist co-activation alongside an agonist), and hyperreflexia. The presentation of this condition can be highly variable as any combination of these symptoms may be reported by the patient. The alteration of the muscular balance about the joints in the upper extremity often initially presents as a dynamic problem characterized by impaired motion. However, prolonged deformity may lead to the formation of contracture (fixed shortening)—a consequence that may impair the active or passive function of the affected limb.
Patients with upper motor neuron syndrome often complain of pain. The reported prevalence of shoulder pain after a stroke has ranged from 24% to 84%2-5. The association between hemiplegia and shoulder pain is unclear, and multiple potential diagnoses should be considered. Several authors have identified rotator cuff tears, decreased range of motion of the shoulder, capsulitis, spasticity of the shoulder musculature, brachial plexus and peripheral nerve injuries, and glenohumeral joint malalignment or subluxation as possible causes of shoulder pain in hemiplegic individuals5-10. Likewise, individuals with spastic deformities of the elbow also frequently report pain11,12, although causative factors have been less clearly elucidated.
Treatment Goals: Active Versus Passive Function
A critical distinction that must be made when evaluating a patient with upper motor neuron syndrome is the determination of the degree of retained volitional motor control of the affected extremity. Patients without any preserved motor control are considered to be hemiplegic, whereas those with some ability to voluntarily move the extremity are regarded as hemiparetic. The goals of treatment are individualized to each patient. However, the notion of functional restoration and alleviation of pain underlie the basic treatment algorithms for patients with spastic limb deformities. In those with no volitional motor control (hemiplegia), spastic deformities and static contractures may lead to skin maceration, poor hygiene, or difficulty with dressing. For this subgroup, treatment thus should revolve around restoration of passive function to allow self-assisted or caregiver-assisted placement of the limb in space. For individuals with preserved voluntary motor control (hemiparesis), improvements in both active and passive function are desired.
As described by Keenan et al.13, several principal questions need to be asked as part of the preoperative planning process: (1) Does the patient have volitional control? (2) Is there a dyssynergy or spastic co-contraction? (3) Is there muscle spasticity? (4) Is there rigidity? (5) Is there contracture? Identifying how much of a deformity is fixed and how much is dynamic is often difficult. Fixed deformities can be a result of severe spasticity or, alternatively, a result of soft-tissue contracture of the muscles, tendons, or ligaments. Passive range of motion of the shoulder and elbow should be attempted first. To help quantify the degree of muscle spasticity about a single joint, the Modified Ashworth Scale can be used1,14,15. Testing of muscle spasticity is performed with the patient in the supine position. For testing of a muscle that primarily flexes a joint, the joint is placed in a position of maximum flexion and is moved to a position of maximum extension over one second. For testing of a muscle that primarily extends a joint, the joint is placed in a position of maximum extension and is moved to a position of maximum flexion over one second.
A score of 0 denotes no increase in tone (no spasticity); a score of 1 denotes a slight increase in tone, with a catch when the limb is moved (mild spasticity); a score of 2 denotes more marked increase in tone, but with the limb being easily moved (moderate spasticity); a score of 3 denotes considerable increase in muscle tone with difficult passive movement (severe spasticity); and a score of 4 denotes rigidity of the limb (very severe spasticity)15.
Evaluating the degree of volitional motor control poses yet another challenge, and the distinction between a hemiparetic and a hemiplegic extremity is important to identify clinically. The evaluation of active motion typically begins with simple movements. The patient should be observed in a variety of different positions and postures, and the shoulder and elbow should be subsequently observed through a variety of both slow and fast motions. Motor control about a single joint subsequently can be classified on a clinical scale as grade 1 (hypotonic, with no active motion), grade 2 (hypertonic, with no active motion), grade 3 (mass flexion or extension in response to a stimulus), grade 4 (patient-initiated mass flexion or extension), grade 5 (slow volitional control of specific joints), or grade 6 (full voluntary control of individual joints)16.
Spastic Postures: Shoulder
The glenohumeral joint is a multiaxial articulation between the proximal part of the humerus and the glenoid fossa. Stability is conferred to the joint by numerous static stabilizers, including the glenoid labrum, the negative intra-articular joint pressure, and the capsular ligaments17. Likewise, several muscles that traverse the joint, working either as agonists or antagonists, confer dynamic stability and govern motion of the extremity. Altered tones of these (spasticity, dyssynergy, or rigidity) often lead to a net imbalance of forces. Depending on the nature of this imbalance, the shoulder can be held in a variety of different postures, including adduction and internal rotation, spastic abduction, and hyperextension.
Patients with spastic adduction and internal rotation dysfunction of the shoulder often present with the proximal portions of the arms held up against the lateral aspect of the chest wall, with the forearms rotated onto the middle of the chest. Spasticity within the pectoralis major as well as the subscapularis, latissimus dorsi, and teres major contribute to this deformity1,6,18-21. Restricted motion often leads to pain as well as difficulty with axillary hygiene and dressing. Pressure sores secondary to skin maceration are also common.
Abduction posturing of the shoulder is often seen in association with selective spasticity of the supraspinatus muscle. Patients generally report global inconvenience in association with this posture, citing difficulties with balance, traversing through doorways, or simply bumping into objects or people in crowds1. Although the contracture can become static, it is generally dynamic and is exacerbated by walking, increased concentration, or use of the contralateral limb. Diagnosis necessitates evaluation of the patient at rest, during walking, and during the performance of various activities22. Both synkinesia (the stimulation of distant limb movements) and vestibular input affect limb positioning and movement. Dynamic electromyography (EMG) shows that the supraspinatus muscle frequently contributes to this deformity1.
Spastic hyperextension of the shoulder is a less-common pattern of spastic posture, but it can occur in association with a relative weakening of the subscapularis and pectoralis muscles. This weakening of the subscapularis and pectoralis major allows the latissimus dorsi, the teres major, and the long head of the triceps to pull the proximal part of the humerus posteriorly and, in effect, to generate a hyperextended shoulder deformity.
Spastic Postures: Elbow
Evaluation of the elbow is similar to that of the shoulder. Spasticity of the elbow as related to upper motor neuron syndrome typically results in a flexion synergy pattern in which the elbow is held in flexed position. Muscle spasticity can be found in the biceps brachii, the brachialis, and the brachioradialis. Although initially dynamic, prolonged spasticity in this posture can ultimately lead to soft-tissue contractures with a resultant static deformity. Severe elbow deformities can lead to difficulties with daily activities, with patients often reporting difficulty with dressing, reaching, and maintaining hygiene23. Moreover, some patients report substantial psychological stress resulting from the cosmetic appearance of the extremity.
Assessment of the spastic shoulder and elbow should always include radiographs to rule out any osseous deformity as a potential source of or contributor to the dysfunction. It has been estimated that approximately 5% of patients with brain injury have development of heterotopic ossification at the shoulder joint, which may affect joint rigidity and alter both passive and active range of motion1. Radiographs also are useful for evaluating for joint subluxation or arthrosis. It is well known that shoulder spasticity can lead to inferior glenohumeral subluxation with consequent degenerative changes9. The combination of spasticity, contractures, subluxation, and arthrosis can be difficult to treat as the pain associated with arthrosis often produces an elevation in muscle tone, thus creating a vicious cycle of pain and spasticity24. Three different radiographs of the shoulder (anteroposterior, scapular-Y, and axillary) should be evaluated. In cases in which spastic adduction prevents the ability to make an axillary radiograph, a Velpeau radiograph will suffice25. A computed tomography (CT) scan is often made for preoperative planning in cases of heterotopic ossification or planned arthroplasty. Heterotopic ossification about the elbow can also lead to dysfunction in patients with upper motor neuron syndrome, and three radiographic views of the elbow (anteroposterior, lateral, and oblique) are required. Although such ossification is rarely seen in the elbows of patients who have had a stroke, it is often seen in the setting of traumatic brain injury and should always be considered as part of the evaluation26,27.
Laboratory analysis with dynamic poly- EMG also has proved to be useful for the evaluation of patients who have spastic upper extremity deformities. In the past, physical examination was the mainstay for clinical decision-making. Dynamic poly-EMG has helped to further characterize these movement disorders and has been shown to improve the outcomes of treatment13,21. With this modality, sensors are placed on multiple muscles and EMG recordings and movement tracings are obtained from specific muscles while the person is moving. EMG analysis can help to identify the presence of motor control; can further aid in differentiating between effort-related initiation, modulation, and termination of voluntary activity within a muscle; and can help to specifically delineate which muscles are spastic. Moreover, dyssynergy or spastic co-contraction can be identified and differentiated from muscle weakness; the former may benefit from surgery, whereas the latter may benefit from rehabilitation13. In practice, this tool is most useful for further evaluating hemiparetic individuals with retained volitional motor control. For instance, limited active forward flexion of the shoulder can result either from weakness of the shoulder flexors or from a restriction secondary to overactive extensors. In this scenario, a poly-EMG analysis may reveal normal agonist activity within the pectoralis major and the anterior deltoid but inappropriate spastic co-contraction of the antagonistic posterior deltoid and the triceps. Thus, selective lengthening (and, in effect, weakening) of the overreactive extensors may improve active function.
Similarly, dynamic EMG can be used to evaluate the spastic elbow and to help guide decision-making among various treatment options, including selective musculocutaneous neurectomy, tenotomy, and tendon lengthening11,28,29. The choice of surgical treatment again depends on the degree of volitional control as well as the degree of muscle spasticity and co-contraction. For hemiparetic patients with mild flexion-type elbow spasticity as delineated with poly-EMG, we often consider musculocutaneous neurectomy as an initial treatment in order to alleviate the spastic burden of the brachialis and biceps muscles. This modality does not, however, take into account spastic hindrance stemming from the brachioradialis muscle. To this end, more severe deformities often require lengthening of the flexors in order to effect improved elbow extension and function.
Neuromuscular blockade also has been found to be useful for the diagnosis, evaluation, and treatment of spastic deformities. Bupivacaine is a local anesthetic that binds to neuronal sodium channels and prevents membrane depolarization. This agent can be injected directly into a muscle, resulting in chemical denervation and selective partial paralysis. The utility of selective neuromuscular blockade becomes apparent when one attempts to differentiate severe spasticity from soft-tissue contracture as a cause of hindered joint motion; deformity caused by spasticity will decrease after nerve block, but deformity caused by a fixed contracture will not change21. In the case of dyssynergy, this blockade also can aid in further elaborating the degree of muscle imbalance between agonist function and antagonist co-contraction about a joint. Should volitional control improve after blockade of the overreactive antagonists, fractional lengthening of these muscles may be warranted. However, if there is no substantial gain in flexion, severe contractures of the musculotendinous units may be present and tendon releases may be necessary.
Longer-acting agents, such as botulinum toxin type A (BTX-A) also can be used for a more therapeutic purpose. BTX-A is a neurotoxin that is prepared from the bacteria Clostridium botulinum. When administered, BTX-A blocks the presynaptic release of acetylcholine at the neuromuscular end plates, resulting in partial chemical denervation. The toxin starts to take effect within a few weeks after injection, with results that can last up to six months30.
Surgical Plan Determination
After upper motor neuron injury resulting from a stroke, there is a period of spontaneous recovery of motor control that can last for approximately six to nine months18,26,31. Decisions can then be made regarding the use of neuro-orthopaedic surgery to correct limb deformities and to rebalance the muscle forces. The preoperative evaluation process for a patient with a spastic shoulder or elbow is complex and varies according to several different patient-related factors and tests as previously described in the current report. We believe that shoulder and elbow tenotomies or muscle releases are appropriate to consider for hemiplegic patients with no voluntary control of the limb (Fig. 1). Although the extremity will remain without active function, these procedures will improve passive function. In our practice, patients with grade-1 motor control have flaccid paralysis and may have shoulder subluxation as a result of hypotonia but rarely have substantial contractures resulting in the absence of tone. Patients with grade-2 or 3 motor control often are better candidates for tendon release than they are for selective lengthening. Patients with grade-6 motor control already function at a high level and may not have substantial improvement after operative intervention. Tendon lengthening can be considered for patients with some retained motor control (i.e., grade-4 and 5 motor control), who have the potential to achieve a greater degree of function as determined with dynamic poly-EMG and/or neuromuscular blockade. In this subgroup, spastic deformities can be the result of contractures or dyssynergy. The goal of selective fractional lengthenings is to weaken the muscle creating the deforming force by lengthening the appropriate motor unit. The lengthened muscle will subsequently contract less efficiently, thus allowing for a more balanced contraction with the relatively strengthened antagonist. Fractional lengthening is technically performed by transecting the tendon where it overlaps with the muscle belly (the musculotendinous junction). The tendon is transected in this region to avoid complete rupture of the muscle-tendon unit. The amount of spasticity in the muscle ultimately determines the amount that the muscle-tendon unit will lengthen.
Review of the Literature: Tenotomy and Lengthening
Aldwell et al., in a study of patients who underwent shoulder tenotomy for the treatment of painful shoulder contracture following a cerebrovascular accident, reported successful relief of pain and restoration of motion (to a mean of 90° of passive abduction and 20° of external rotation) in ten patients at the time of early follow-up32. Similarly, Braun et al., in a study of forty-one patients who were managed with tenotomy for the treatment of painful shoulder contracture following a stroke, reported that range of motion qualitatively improved in eighteen patients after a mean duration of follow-up of twenty months6. The authors hypothesized that poor postoperative motion was associated with noncompliance with a home exercise program. Keenan and Mehta, in a study of patients who underwent treatment of shoulder deformity after traumatic brain injury, noted qualitatively improved passive resting position and range of motion in all ten shoulders1. Most recently, Namdari et al. demonstrated the efficacy of tendon releases in a study of thirty-six adult hemiplegic patients with shoulder adduction and internal rotation deformities and grade-5 motor control following upper motor neuron injury14. The patients underwent tenotomies of the pectoralis major, latissimus dorsi, teres major, and subscapularis muscles. After an average duration of follow-up of 14.3 months, the authors reported significant improvements in passive extension, flexion, abduction, and external rotation when compared with the contralateral side (p < 0.001). All patients who had presented with pain preoperatively reported improvement, with 95% being pain-free at the time of the latest follow-up. Thirty-five patients (97%) were satisfied with the outcome of surgery. Complications included two hematomas that resolved without intervention. In our experience, we have found that shoulder tendon or muscle releases are a reliable surgical option to alleviate pain and increase passive range of motion in hemiplegic patients with spastic adduction and internal rotation, abduction, or hyperextension shoulder deformities (Table I).
Shoulder Tendon Lengthening
In practice, we have found shoulder lengthening procedures to be particularly successful for hemiparetic patients with spastic deformities (Table I). Historically, studies regarding the outcomes of tendon lengthening in patients with spastic hemiparesis have been limited to pediatric populations, with several of these case series demonstrating successful outcomes of tendon lengthening after brachial plexus injury33-35. Namdari et al. evaluated the outcomes of fractional lengthenings of shoulder tendons (including the pectoralis major, latissimus dorsi, and teres major) in a study of thirty-four adult patients with spasticity and preserved volitional control36. After a mean duration of follow-up of one year, gains were most profound in active external rotation, although significant gains were also achieved in active flexion and abduction (p < 0.001) as well as passive motion (p < 0.01). Ninety-four percent of the patients with preoperative pain reported relief of pain postoperatively, and 92% reported satisfaction with the outcome of surgery.
As the supraspinatus is not a muscle that is amenable to fractional lengthening, it is possible to effectively lengthen the supraspinatus by means of a slide procedure37. This procedure was previously described by the senior author (M.A.K.)22 and has been used successfully to correct spastic abduction deformities (Table I). An incision is made parallel to the scapular spine. The trapezius insertion is detached from the spine of the scapula, leaving a cuff of fascia for later reattachment. The deltoid is retracted laterally. With use of a small periosteal elevator, the origin of the supraspinatus is elevated subperiosteally from the medial border of the scapula. The dissection is continued laterally, with care being taken to avoid injury to the neurovascular pedicle at the suprascapular notch. The muscle is then allowed to slide laterally. The trapezius is then repaired to the scapular spine. Postoperatively, the patient is allowed to perform unrestricted motion. We are not aware of any study that has specifically evaluated the outcomes of this technique.
The literature on the treatment of hemiplegic elbow spasticity has been mostly limited to the pediatric population, with several authors describing successful results in association with neurectomy of the musculocutaneous nerve, elbow flexor tendon lengthening, and muscle releases38,39. Few studies have investigated the surgical treatment of spastic elbow deformities in adults with upper motor neuron syndrome. In our practice, the surgical approach to the spastic elbow in hemiplegic patients involves releases of the muscles and tendons of the elbow (Table I). Most recently, Namdari et al. evaluated twenty-nine hemiplegic patients with spastic flexion-type elbow deformities that had developed after upper motor neuron injury12. Tenotomies of the brachialis, brachioradialis, and biceps were performed, and, after a mean duration of follow-up of 1.7 years, the mean passive elbow extension deficit had improved from 78° to 17°. All patients with preoperative pain reported pain relief, and 94% were pain-free.
Elbow Tendon Lengthening
Studies evaluating the efficacy of tendon lengthening in the spastic elbow have largely been performed in the pediatric population. Mital described successful improvement of elbow flexion in a study of twenty-six children with cerebral palsy who were managed with selective Z-lengthening of the biceps tendon and fractional lengthening of the brachialis38. Keenan et al., in a study of adult patients with brain injury who were managed with proximal release of the brachioradialis, Z-lengthening of the biceps tendon, and myotendinous lengthening of the brachialis muscle as a means of restoring elbow motion, reported a mean improvement of 49° in the arc of elbow motion40. Most recently, Anakwenze et al., in a study of forty-two hemiparetic patients who were managed with myotendinous lengthening of the elbow flexor muscles for the treatment of elbow flexion deformities after upper motor neuron injury, reported significant improvement in mean active extension from 42° to 20° (p < 0.001) after an average duration of follow-up of fourteen months11. Complications included two cases of superficial wound dehiscence that were treated nonoperatively. In our experience, we have found tendon lengthening to be a reliable modality to relieve pain and improve active and passive range of motion in hemiparetic patients with spastic flexion elbow deformities (Table I).
Spastic deformities of the shoulder and elbow are often seen in the adult population after injury to the upper motor neuron system and often lead to undesired sequelae such as pain and difficulty with activities of daily living. These spastic conditions are uniquely variable and frequently present diagnostic and treatment challenges to the orthopaedic surgeon. It is important to determine the degree of spasticity as well as the level of volitional motor control through careful evaluation of the patient. Radiographs can be used to rule out any osseous abnormalities, and the combination of dynamic poly-EMG analysis along with selective neuromuscular blockade can help to delineate the pattern of motor function. When the appropriate treatment strategy is selected, the spastic shoulder and elbow can be successfully treated with tendon releases or fractional tendon lengthenings.
Source of Funding: No external funds were received in support of this study.
Investigation performed at Rothman Institute, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania
Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. One or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. In addition, one or more of the authors has a patent or patents, planned, pending, or issued, that is broadly relevant to the work. Also, one or more of the authors has had another relationship, or has engaged in another activity, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
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