Introduction
Spasticity, characterized by muscle hypertonia, is linked to a central neurological impairment involving the pyramidal tract. It is caused by a hyperactive stretch reflex mechanism. It may occur in several circumstances. In children, the usual cause is cerebral palsy. In adults, it is usually related to vascular or traumatic brain damage or, less frequently, to tetraplegia.
Spasticity rarely occurs in isolation. The clinical picture generally includes other neurologic and orthopedic impairments that also need to be carefully assessed. The clinical picture, i.e., the extent and severity of the brain insult, varies greatly among patients. A thorough clinical examination, standardized charting, and repeated video recordings are key elements for decision-making and achieving a successful outcome.
Clinical classification (Caroline Leclercq)
Cerebral palsy.
Cerebral palsy has been defined as a group of permanent disorders related to the development of movement and posture that are linked to nonprogressive disturbances that occurred in the developing fetal or infant brain. Perinatal asphyxia is responsible for 5% to 10% of cerebral palsy cases. Other causes include meningoencephalitis, traumatic brain injury (TBI), and cerebrovascular accidents related to congenital vascular malformations. Hemiplegia is the most common manifestation of cerebral palsy. It develops progressively during growth; however, once established, it follows a nonprogressive course, making it amenable to surgical treatment in selected cases.
Cerebrovascular accidents.
Cerebrovascular accidents (CVAs) usually affects senior patients. There is an initial flaccid phase, and spasticity occurs after a few weeks and progressively affects the recovering muscles, frequently leading to muscle contractures. Sensation is often severely impaired in the hand, leading to neglect and impairing functional recovery. These features may not allow surgery to restore function. However, procedures aimed to reduce spastic contracture and improve hygiene and nursing are helpful in a number of cases.
Traumatic brain injury.
The initial trauma may involve various portions of the brain and cerebral trunk, and the clinical features will vary accordingly. Motor impairment depends on the extent of brain damage. It may recover quickly in some patients but remain severe in others. Muscle contractures may develop rapidly and must be corrected surgically, if needed. Other neurologic disorders are often predominant, e.g., cerebellar syndrome and cognitive or frontal impairment, many of which prevent surgical attempts to improve function in the upper limb.
Tetraplegia.
Spasticity in patients with tetraplegia usually occurs in the lower limbs. According to Zancolli, it affects the upper limbs in 15% of patients, mainly in the wrist and fingers in patients with incomplete tetraplegia. Spasticity, when moderate, can be useful to the patient and does not interfere with surgical rehabilitation of the tetraplegic upper limb. Severe spasticity causes deformities that must be corrected prior to reconstructive surgery. When a deformity is predominant, surgical rehabilitation may not be possible.
Other causes.
Patients with multiple sclerosis, Parkinson disease, and other rarer neurologic conditions may be affected by spasticity in their upper limbs. Indication for surgery is not frequent in these progressive diseases.
Pathologic development of muscle spasticity (Eva Ponten)
Brain injuries cause functional impairments to motor neurons and result in smaller and stiffer muscles, leading to spasticity. If the brain injury occurs during gestation or before the age of two, it is defined as cerebral palsy. Acquired brain injuries after the age of two will also result in reduced growth and smaller muscles of the paretic limb(s). In adults who have sustained a stroke, the muscles in the most affected limbs will become atrophied, at least partly because of disuse.
Although the brain damage is stationary, its peripheral effect on muscle progressively changes. , In cerebral palsy, immature reflexes remain, and the immature spread of the neuromuscular junctions along the muscle fiber is not pruned as it should be. , The neural signaling to the muscle is thus altered. Using ultrasound, muscle volume measurements of the gastrocnemius in children with cerebral palsy have shown that atrophy and reduced growth of the muscle occurs at 15 months of age. Reduction of muscle length and volume then progresses during growth, shown both with ultrasound measurements and with clinical follow-up in population studies of both the upper and lower limbs. , ,
In the upper limb, hampered growth of the muscle is evident in both girth and length, and the muscle is also stiffer. , The sarcomere is the smallest contractile unit of the muscle, where the myosin and actin interdigitate during contraction, and has been measured during upper limb surgery in cerebral palsy. When the wrist is neutrally positioned, sarcomeres of the wrist flexors are longer; the more flexion contraction in the wrist, the shorter the sarcomeres. This is an indirect sign that there are fewer sarcomeres in series in contracted muscles and that muscle fibers are smaller. , Such changes are more remarkable in tetraplegic cerebral palsy than in hemiplegic cerebral palsy and also in contracted wrist flexors than in elongated and weak wrist extensors.
The cause of these muscle alterations is not clear. Some of the changes are probably caused by disuse, but the muscle changes have only a few similarities to those seen after immobilization. Spasticity and myopathy of the muscles in cerebral palsy occur more in parallel rather than by cause and effect, and reduction of the spasticity by selective dorsal rhizotomy has not been shown to reduce contracture formation, even though spasticity is decreased. Botulinum toxin (BT) may be administered to reduce spasticity with the hope that it will inhibit contractures, but when treating plantar flexors, extension of the foot continues to decrease. In a group of children who were treated with splinting and training of the upper limb, addition of BT injection did not improve the treatment effect. The spastic muscle not only reacts with a diminished inhibition of the stretch reflex, but the muscle, per se, is thinner, stiffer, and weaker and shows reduced growth potential.
Clinical presentation and evaluation (Caroline Leclercq)
The clinical picture may vary greatly among patients depending on the location and extent of the brain insult. Regardless of the deformity’s cause, the clinical examination should be conducted in the same manner. It is a critical part of the assessment and the principal element used to guide surgical decision-making. In a clinical examination, the provider seeks to detect and assess all factors responsible for the deformity, each of them requiring a specific treatment. The goal is fourfold: (1) evaluate spasticity, (2) evaluate the possible muscle contracture and joint deformity, (3) evaluate the motor and sensory impairment in the upper limb, and (4) evaluate existing function and the functional needs of the upper limb.
The assessment is completed via a general examination to assess for associated neurological disorders and potential contraindications to surgery. The data are recorded on standardized charts, which will allow intra- and intercomparisons of the outcome.
Video recording is a developing tool used in the evaluation of spastic upper limbs. It is best performed in a dedicated space, with two cameras positioned perpendicular to each other, according to a standardized scenario adapted to the patient’s deficit. The video recording is extremely valuable, especially in children who cannot endure a lengthy clinical examination. It should be repeated preoperatively, posttoxin injection, and post-surgery.
This examination is best performed as a team, including all the specialists (physical therapist, occupational therapist, physiatrist, neurologist, and surgeon) involved in the patient’s care. It should ideally be done in a warm, quiet, and friendly environment.
Clinical manifestations within the same patient may vary greatly with a number of factors, including the patient’s emotional state and fatigue level, ambient temperature, and the time of day. Therefore, it is unwise to decide on surgery after a single session, and assessment should be repeated before any decision is made. Standardized assessment charts and video recording are performed before and after each step of treatment.
Evaluation of resting posture of the upper limb
Inspecting the limb at rest prior to examination provides much information on spasticity. It usually predominates in the adductor, flexor, and pronator muscles, leading to a typical resting posture in shoulder adduction and internal rotation, elbow flexion, forearm pronation, and wrist flexion ( Fig. 33.1 ). However, on occasion, some patients display very different postures, such as shoulder abduction and external rotation (most often in children with quadriparesis) and elbow or wrist hyperextension.
The fingers may assume varied positions. Most frequently, they are clenched into a tight fist. Less typically, they assume a swan neck deformity, an intrinsic-plus deformity with flexion of the metacarpophalangeal (MP) joints and hyperextension of the interphalangeal (IP) joints, or the opposite, intrinsic minus deformity, with the MP joints hyperextended and the proximal interphalangeal (PIP) joints flexed. A boutonniere deformity is less common.
The thumb can assume either an adducted or an adducted and flexed posture, often referred to as “thumb-in-palm,” where the thumb is embedded in the palm with full flexion of both MP and IP joints, preventing any use of the hand ( Fig. 33.2 ).
Evaluation of spasticity
Spasticity is a muscle hypertony, characterized by five classic clinical features ( Box 33.1 ).
- 1.
It is selective, predominantly involving the flexor, adductor, and pronator muscles and is responsible for the characteristic “flexion-pronation” deformity of the upper limb.
- 2.
It is elastic. Attempts to reduce the deformity meet with resistance, which increases with the strength applied. If the opposing force is maintained long enough, the deformity usually yields, but the limb returns to its initial position as soon as the force is removed.
- 3.
It is present at rest and exaggerated with voluntary movement, emotion, fatigue, and pain.
- 4.
Osteotendinous reflexes are exaggerated, brisk, diffuse, and polykinetic.
- 5.
There may be associated synkineses, which is the phenomenon whereby paralyzed muscles incapable of a certain voluntary movement execute this movement in a voluntary fashion by accompanying normally controlled muscles.
The shoulder is usually relatively spared, except for the pectoralis major and the subscapularis. At the elbow level, spasticity predominantly involves all three flexors, but the triceps can also be spastic. Spasticity of the wrist flexors and pronators leads to the characteristic hyperflexed and hyperpronated deformity. Finger spasticity is difficult to assess if the wrist is hyperflexed. The finger flexors are frequently involved, which renders evaluation of the interossei muscles difficult. All thenar muscles may be affected.
Quantitative evaluation of spasticity is challenging. The classic Ashworth and modified Ashworth scales have been recognized as too subjective. The Tardieu scale, which assesses the passive motion (V1), angle of catch at fast speed, (V3), and mode of the catch (T), is more accurate and reliable. Although it was described as early as 1954, it has only recently gained popularity.
Muscle contracture
Muscle contracture is a result of longstanding, unopposed spasticity of muscles. Unlike spasticity, it is permanent and cannot be overcome, although shortening the involved articular segment can alleviate it. For example, posturing the wrist in flexion relieves contracture of the finger flexors. This is assessed using the Volkmann angle, which is the degree of wrist flexion required to obtain full passive finger extension. Contracture of the intrinsic muscles of the fingers is assessed using the Finochietto test. Clinical distinction between contracture and spasticity may be difficult to establish. In such cases, nerve blocks or BT injections are useful.
Joint deformity
Passive motion of the involved joints may be difficult to assess because of associated muscle contractures. Sometimes, it is not until muscle contractures have been surgically released that the actual range of passive motion can be evaluated. In children with spasticity, increased passive extension of some joints may result in joint instability, mostly at the thumb MP joint and at the finger PIP joints (leading to a swan neck deformity).
Motor assessment
Motor examination of the spastic upper limb is difficult, especially when the deformities are severe. The flexor, adductor, and pronator muscles, mostly spastic, usually retain some voluntary control. Assessing their strength with the classic Medical Research Council (MRC) grading scale may be challenging when severe deformities are present.
Cerebral palsy usually predominates distally and involves the antagonist muscles (extensor and supinator muscles). Rather than actually being paralyzed, these muscles may be functional but made ineffective by the spastic agonists. BT injection into the spastic agonists can be helpful. By decreasing their tone, a proper evaluation of the “paralyzed” muscles can be performed, which may reveal satisfactory voluntary control.
Spontaneous involuntary movements are recorded. Dystonia, characterized by unvoluntary intermittent muscle contractions causing repetitive movements and/or abnormal postures, is common in patients with cerebral palsy. When dystonia is predominant, surgery is contraindicated.
Some attempts at classification of the spastic upper limb have been made. ,
Aside from Tonkin’s specific thumb classification, we have not found any of the classifications very helpful because of the infinite range of clinical pictures, many of which do not fit into any of the described categories.
Sensory examination
The basic sensory functions (light touch, pain, temperature) are usually less readily affected than complex sensations (fine sensibility, proprioception, stereognosis). Pain may be difficult to evaluate in patients with speech impairment. It may be linked to severe contractures, a deformed joint, or, occasionally, at the wrist level, to Kienböck disease secondary to a severe hyperflexion deformity.
Functional assessment
A large variety of tools and tests have been designed to assess the functional value of the spastic upper limb. Some tests are analytic, assessing a single function (pick up test, nine-hole peg, etc.); others are functional, assessing capacity (ability to execute a task at the highest possible level of functioning) or performance (spontaneous use of the upper limb in activities of daily living) ; and some are mixed. , Patient autoevaluation and questionnaires give information on the actual use of the hand, especially in patients with hemiplegia whose spastic hand may be neglected despite some real functional capacity. Whichever assessment is used, it should be video recorded. This is repeated after each therapeutic step to allow for evaluation and comparison of the results.
Computerized systems allowing 3D analysis of movement are regularly used in cases involving spastic lower limbs. They have recently been advocated for use in cases involving the upper limbs in an attempt to quantify hand grasp and release. ,
General preoperative assessment
Lower limb deficiencies must be assessed along with the potential need for walking aids. If required, these deficiencies are usually corrected before upper extremity surgery. Central deficiencies such as visual, auditory, language, cognitive, and behavioral problems are also taken into account in the decision-making.
Imaging and electromyography
Joint deformities must be explored radiologically for possible heterotopic bone formation, especially around the elbow in patients with TBI. Patients with cerebral palsy may display growth disturbances of the distal radius, ulna, and carpus, occasional avascularity of the lunate, or dislocation of the radial head.
Electromyography (EMG) studies provide information on the spastic muscles (voluntary control, phasic control), as well as on possible co-contractions of the antagonist muscles. However, they do not provide quantitative information on the power of the tested muscle. Dynamic EMG studies are useful to determine the most appropriate donor muscles when planning a tendon transfer. Most of the potential donors are spastic to some degree. They can be used only if the patient has phasic control (the ability to relax at rest or during the antagonist movement). ,
Botulinum toxin injection for clinical evaluation
BT is effective for evaluation of local muscle spasticity. Injected directly into the target muscle, it results in a reduction of spasticity lasting up to several months. It is now routinely used in spastic upper limbs with measurable and reproducible effects. , We use it mostly as a diagnostic and preoperative tool to decide which muscles would benefit from permanent surgical reduction of spasticity. This is particularly informative when multiple muscles contribute to the same function. BT also helps to evaluate the antagonist muscles: If properly exercised after injection of the spastic muscles, weak antagonists may regain adequate strength, rendering complementary rebalancing procedures such as tendon transfers probably unnecessary. BT can help detect spasticity in other muscle groups, such as intrinsic muscles of the fingers. In some cases, BT plays an educational role in simulating the effect of surgery.
Following injection of BT directly into the muscle belly, it is fully effective after 2 to 3 weeks. Its effect lasts between 4 and 6 months. Injection can be performed under manual control for large superficial muscles (palpation of muscle contraction), but electrostimulation or ultrasound control are necessary for deeper and smaller muscles.
Preoperative evaluation is repeated at the time of maximum efficacy (usually 2 months) and again at 6 months post-injection. When the goal is to evaluate the antagonist muscles, selective exercising of these muscles is initiated 1 week post-injection, usually complemented by a night splint.
We stress that clinical examination aims to analyze different factors of the spastic deformity to determine a specific treatment for each of them. It is a difficult and lengthy process and is best performed with all care givers involved in the treatment. Repeated examination, standardized charts, video recording, and BT injection are mandatory steps that will be the basis of decision-making.
Evidence for clinical strategies (Shai Luria)
Indications and the choice of procedures are currently based primarily on expert opinion, and these treatment decisions remain debatable. , Different studies have evaluated improvement in range of motion or stereognosis, but the complexity of these cases requires the evaluation of the actual improvement in function. This takes into account the diversity of clinical presentations, the typical disregard of the involved limb, movement disorders such as dystonia, sociodemographic factors, patient and family expectations, and the quality of therapy. ,
Examining function requires outcome instruments with sufficient resolution to reveal improvement, which may be minor in many cases, and minor improvements can have noteworthy functional implications and may be the difference between a limb of no use and a limb capable of passive assistance. The Shriners Hospital Upper Extremity Evaluation (SHUEE) and the Assisting Hand Assessment (AHA) functional measurement techniques were developed for the evaluation of unilateral upper limb dysfunction. , They have grown in popularity and are useful tools for the comparison of results across studies. The SHUEE has also been shown to successfully differentiate static from dynamic function. Both instruments quantify and record function in surroundings that are less intimidating to the patient, thus allowing the surgeon and the rehabilitation team to reexamine function in detail before and after any intervention ( Fig. 33.3 ).
Most of the relevant literature has a level of evidence of 4 and reports retrospectively on specific procedures performed as part of a multilevel approach. Given that no two cases involving spasticity are alike, knowledge of different techniques is crucial to adequately address dysfunction, with a choice of procedures tailored to the patient’s specific deformities. For example, to treat shoulder dysfunction, will tenotomies result in functional gain, and which muscles should be released? Which elbow flexor should be released, and when is there an advantage to a neurectomy? Is there an advantage to rerouting the pronator teres (PT) to gain active supination, and can one tendon transfer addressing pronation and wrist flexion deformity replace two separate transfers? Are there comparative studies to guide us on the procedures that will result in the best functional gain? Past reports provide some, but not complete, evidence to answer such questions.
A major issue that has evolved in the past few years is the use of neurectomies. Previously, these were aimed at extremities with little function. Recent reports indicate hyperselective neurectomies may afford better function and improved hygiene and appearance. In a recent study involving both children and adults, neurectomies designed to treat different joint deformities improved function and maintained the muscle’s strength. This is a potential advantage compared to the inevitable weakening caused by tenotomies. A comparison of neurectomy and tenotomy used to address a specific deformity, such as elbow flexion, in adults or children is not yet available to aid in the choice of procedure.
Another choice is whether to deal with forearm pronation and wrist flexion deformities together or to use two separate transfers. A single transfer of the PT to the extensor carpi radialis brevis (ECRB) can address both deformities. The available studies comparing this single transfer for both to procedures directed at only one of the two deformities reported inferior results in terms of range of motion and, to some extent, inferior function. , The multilevel surgical approach was discussed in a few reports. , , This information allows us to council families and make surgical plans with much more confidence.
We are left with the choice of specific procedures to be included in this combination. Specific options for each deformity should be better correlated with functional gains. Other questions remain, given the lack of evidence in the literature on the timing of surgery and the effects of disregard or dystonia of the involved limb on surgical results. At this time, textbook descriptions, training, and expert opinion continue to guide these choices.
Clinical decision-making and surgical strategies (Caroline Leclercq)
The decision-making process should include the patient and family, as well as all of the physicians and caregivers involved in the treatment. Typically, this occurs after several assessment sessions and video recordings of the patient’s functional capabilities. The patient’s ability to understand the goal, modalities, and expected benefit of the proposed treatment may be a challenge, particularly in patients with cognitive impairment. Family support and local rehabilitative resources are determinants, as the postoperative regimen frequently requires multiple rehabilitative sessions, orthoses, and medical appointments.
The aim of the surgical treatment must be clearly defined from the start. Based on the House classification, the spastic hand may be roughly considered as nonfunctional in groups 0 and 1 and functional or potentially functional in groups 2 and above. Improving function is the ultimate goal. In nonfunctional hands, other types of improvements may be of considerable value to the patient, such as decreasing pain and improving comfort, nursing care, hygiene, and appearance. Surgery is generally not indicated when dystonic movements are predominant. Figs. 33.4 and 33.5 depict our surgical strategies for treating functional and nonfunctional upper limbs, respectively.
In cerebral palsy, because the neurological deficit is nonprogressive, surgery can be undertaken early. Later on, children usually develop tricks that allow them to perform some activities but prevent the return to more functional patterns after surgery. Another advantage of early surgery is that improved use of an extremity can improve cortical representation of that extremity and, we hope, decrease the development of neglect. Neglect, in turn, aggravates any sensory deficiency, creating a vicious cycle of disuse. In addition, early surgery may prevent the formation of contractures ( Fig. 33.6 ). Tonkin stated that “the ideal candidate is a cooperative 6-year-old child, with stable family support, who has a predominantly spastic upper limb deformity with satisfactory hand sensibility, hemiplegic or monoplegic, and without significant neurological deficits.”
Adolescents with cerebral palsy often ultimately seek cosmetic improvement, although they may have difficulties in expressing their wishes. In the case of CVAs, surgery may be considered once the neurological status is stable. Persisting upper limb neglect often rules out any hope of functional improvement, but surgery may be indicated to reduce pain and improve comfort, nursing care, hygiene, or appearance.
Patients with TBI may develop early and severe muscle contractures, which may require early intervention. The decision to undertake any functional surgery depends upon the recovery of adequate cognitive functions, and longer delays may be required. In select cases, deformities, pain, hygiene, and nursing difficulties can be dramatically improved by surgery.
A number of other elements must be taken into account when making the decision to operate on the upper limb of a patient with spasticity. Lower limb deficiencies may create specific needs in terms of walking aids or wheelchair motion. A deficit of the upper functions, such as vision, hearing, or language skills, may also create specific functional needs. Cognition or behavior problems require that the patient’s compliance to any proposed surgery and postoperative rehabilitation be assessed.
Classic treatment methods (Caroline Leclercq)
The spastic hand represents one of the most challenging problems in upper limb reconstructive surgery. Surgery is only one element of the rehabilitative care, which includes primarily physiotherapy and splinting, occupational therapy, and pharmacological treatment.
Botulinum toxin
BT is effective in locally reducing muscle spasticity. Injected directly into the target muscle, it reduces spasticity for several months. We use it routinely as a diagnostic and preoperative tool to determine the appropriate surgical planning.
In some cases with severe spasticity, BT allows us to distinguish between muscle contracture and spasticity. Also, when multiple muscles contribute to the same function, it helps us decide which muscles would benefit from a permanent reduction of spasticity. It is particularly informative regarding the antagonist muscles. They may seem paralyzed or very weak, but after injection of the agonists followed by an intensive period of strengthening and splinting, they may end up demonstrating satisfactory voluntary control. The function of BT in this setting is also educational, as it somewhat mimics the results of surgery, thus demonstrating to the patients the results that can be expected.
Surgical methods
The surgery often involves several joints from the shoulder to the fingers and thumb and many different tissues. It is best performed in a single session whenever possible. Otherwise, the choice is usually to operate from proximal to distal, unless one deformity is outstanding.
Rebalancing the forces.
All the components of the deformity, i.e., spasticity, muscle contracture, joint contracture, and paralysis, must be taken into account to restore an appropriate balance of forces around the involved joint. Three types of procedures may be indicated, in isolation or together: (1) those to reduce spasticity, (2) those to reduce muscle and/or joint contracture, and (3) those to reinforce paralyzed muscles.
Reducing spasticity.
In addition to local pharmacological agents such as nerve blocks and BT, focal spasticity can be reduced surgically with durable effects.
- (1)
Partial neurectomy: Partial (or selective) neurectomy consists of resecting some of the motor nerve fascicles of a muscle. This technique will be discussed in the section of hyperselective neurectomy.
- (2)
Neurosurgical procedures: Treatment of spasticity by posterior rhizotomy is frequently used for spasticity of the lower limbs with reliable effects on gait. In the upper limbs, however, outcomes have been variable and with moderate functional benefit. Bertelli reported a significant reduction of upper limb spasticity with a technique of brachial plexus dorsal rhizotomy in 61 children or adolescents with spastic hemiplegia.
Muscle contracture.
Several types of procedures can be used to overcome muscle contractures.
- (1)
Tenotomy: Before performing a tenotomy, one should make sure that there would not be a better use of the tendon as a donor for transfer (usually the flexor carpi ulnaris [FCU] or PT). Multiple tenotomies performed in a single stage are useful in cases of severe contractures occurring in a nonfunctional upper limb to improve hygiene nursing care.
- (2)
Muscle release: Contracted muscles may be released at their proximal bone insertions, at their musculotendinous junctions, or distally within the tendons.
The classic flexor-pronator release consists of detaching the proximal attachment of the wrist flexors and PT from the medial epicondyle. If extended to the finger flexors, it is referred to as the Scaglietti-Page procedure. The skin incision is extended distally, and all the finger flexor origins are freed from the anterior aspect of the ulna and radius. This invasive procedure requires careful hemostasis and postoperative suction drainage.
Zancolli described a more limited transverse resection of the inter- and perimuscular fascia of the same flexor-pronator muscles performed 6 cm distal to the medial epicondyle (“flexor aponeurotic release”). This procedure is reportedly more effective in children than in adults because of the frequent presence of myostatic contractures in adults.
Fractional lengthening consists of multiple transverse incisions of the tendon in the area where muscle and tendon overlap ( Fig. 33.4 ). It is less invasive and easier than proximal release. However, some muscles may not have sufficient muscle-tendon overlap, and a careful perioperative evaluation is required to avoid tendon rupture. Postoperatively, no immobilization is required, and early active motion is initiated.
Z lengthening of each individual tendon, simple when only one or a few tendons are involved, becomes time consuming and a potential source of adhesions if it involves many tendons (e.g., finger flexors). It is mostly indicated when fractional lengthening cannot be performed, namely for the biceps, the flexor carpi radialis (FCR), and some flexor digitorum superficialis tendons.
Releasing joint contractures.
None of the previously mentioned procedures are effective in the presence of joint contracture. If after all muscle contractures have been eliminated passive motion is still limited, additional joint procedures may be considered. However, indications for conventional arthrolysis are limited in the spastic upper limb in view of the frequently associated muscle contractures and paralysis of the antagonist muscles. Postoperative rehabilitation is challenging, and results are less reliable than those for other causes of joint stiffness.
A fixed pronation deformity may require a release of the interosseous membrane. Severe long-standing deformities in adults may only respond to an osteotomy in the forearm. Arthrodesis in a more favorable position is indicated mostly at the wrist level in cases involving a severe nonfunctional deformity.
Tendon transfers.
Tendon transfers are necessary when the paretic or paralyzed muscles require augmentation to rebalance forces in a functional hand. They are usually performed to improve forearm supination, wrist extension, thumb extension-abduction, and finger extension. The differences between such tendon transfers and those for other disorders are shown in Box 33.2 . Dynamic EMG studies are helpful in selecting adequate muscles for transfer. ,
- 1.
Muscles available for transfer vary with each patient. A spastic muscle can be selected as a donor, provided it is strong and phasic. Dynamic electromyography studies are helpful in selecting proper muscles. Muscles most often selected are the flexor carpi ulnaris, extensor carpi ulnaris, flexor digitorum profundi, and brachioradialis.
- 2.
Tendon transfers will be successful in activating a paralyzed muscle only if the spastic or contracted antagonist muscles are attenuated or released prior to or at the time of tendon transfer.
- 3.
Rehabilitation must carefully monitor the transferred muscle, and longer immobilization is often required.
Contraindications for surgery
General contraindications for surgery in patients with spasticity of the upper limb include dystonia or abnormal movements, lack of compliance, and unrealistic expectations.
Cognitive problems are not necessarily a contraindication as long as the patient can cope with a surgical procedure and the associated postoperative care.
Hyperselective neurectomy (Caroline Leclercq)
Focal spasticity can be treated using neurolytic and chemodenervation therapy, but the effects are temporary, ranging from a few hours (nerve blocks) to a few months (BT). Nerve procedures aim to reduce the tone in the spastic muscles and can be performed at the level of the peripheral nerves, spinal roots, spinal cord, or dorsal root entry zone.
Selective neurectomy consists of dividing some of the fascicles of a motor nerve. This procedure was suggested as early as 1913 by Stoffel in an attempt to retain some function. It has become a standard procedure in the lower limb but only gained some popularity in the upper limb after Brunelli and Brunelli published a clinical series in 1983. They initially advocated dividing 50% of the fascicles, but after experiencing recurrence of spasticity, they recommended resection of a greater number.
The procedure has recently been refined to hyperselective neurectomy (HSN), in which a partial neurectomy is performed at the junction of each motor ramus with the target muscle ( Fig. 33.7 ). Another major development has been a better understanding of the motor anatomy of upper limb muscles allowing establishment of guidelines for the surgical technique.
Indications and contraindications
HSN reduces the spastic component of the limb deformity. It has no effect on muscle or joint contractures, which should be addressed using other surgical techniques. These include muscle or tendon lengthening, arthrolysis, and arthrodesis. Paralysis of the antagonist muscles must also be addressed, when possible, using specific reconstructive procedures.
Surgical techniques
Depending on the patient and the involved nerve, HSN can be performed under axillary block or general anesthesia. Tourniquet control is used for forearm procedures. Because of the need for intraoperative nerve stimulation, curare injection is contraindicated. It is recommended to use loupe magnification and microsurgical instruments.
The skin incision follows the guidelines derived from anatomical studies. Once the nerve trunk has been exposed, the motor branches are meticulously dissected. As there can be great variability in the distribution of motor branches to the upper limb muscles, intraoperative neurostimulation helps identify every single motor branch and avoid any sensory branches ( Fig. 33.8 ). There are usually several rami for each involved muscle. Each ramus is dissected up to its entry point into the muscle. Then, using microsurgical instruments and magnification, fascicles are resected from each ramus. This most commonly consists of removing two-thirds of them, depending on the degree of spasticity and the desired result. Coagulation of the proximal stump to prevent nerve regrowth is not recommended, as secondary sprouting of the motor fibers will nonetheless occur.
To simplify the procedure, some authors perform a partial neurectomy at the level of the main nerve trunk without approaching the target muscle(s). The motor fascicles are identified proximally within the nerve trunk using a stimulator and are partially resected. Although less invasive with limited exposure, this truncular neurectomy technique is less precise, with possible failures secondary to inadequate nerve branch identification and potential injury to sensory fibers.
Postoperative care
Gentle exercises of the involved muscles and antagonists are initiated 1 week after neurectomy. A temporary paresis of the target muscles is common during the first few weeks. In cases in which this technique is performed concomitantly with other rebalancing procedures (e.g., tendon lengthening, tendon transfers), the postoperative regimen will vary according to the requirements of these other procedures.
Outcomes
A prospective study was performed on 42 patients who underwent isolated HSN of a joint area (elbow, forearm, or wrist) for pure spasticity without associated contracture. The results were assessed at 6 months (early follow-up) and at the last visit (late follow-up), with an average final follow-up of 31 months. All evaluations included spasticity as measured by the Tardieu and modified Ashworth scales, resting posture of the limb, active and passive range of movement, muscle strength of both the muscles altered in surgery and the antagonists, functional results as measured by the House scale, goal attainment, and patient satisfaction.
HSN was performed on 101 muscles in 42 patients of our unit. The results demonstrated effective reduction of spasticity. We found a noteworthy improvement of the resting posture of the operated limb segment. Another important finding of the study was the conservation of strength, despite removing two-thirds of the motor branches. There was no overall improvement in the range of active motion because of the absence of initial muscle contracture in this selected group. There was a marked improvement in upper limb function according to the House and goal scales.
The comparison of early and late follow-up showed a slight, insignificant relapse of spasticity, and long-term data showed stability of the outcome. There were no significant differences when comparing different joints, apart from a noteworthy increase of strength in the antagonist muscles at the level of the forearm and of the wrist but not at the elbow (where the antagonist triceps is rarely paretic).
There were no immediate postoperative complications in this group of patients. Although in some cases there was a transient loss of strength, no patients complained of permanent loss of strength. There were no instances of sensory nerve irritation, even transient. Two patients underwent additional surgeries for ongoing spasticity of the brachioradialis after HSN of the musculocutaneous nerve (MCN) for a spastic elbow. Both improved after HSN of the motor branches of the radial nerve to the brachioradialis.
Our results are in keeping with other favorable results that have been reported after partial neurectomies in the upper limb. , , However, there is little consensus regarding evaluation, indications, technique, and postoperative outcomes. In an effort to address these challenges, we systematically reviewed the literature regarding different techniques for partial neurectomy in the upper limbs of patients with spasticity. A meaningful comparison with other series remains challenging. Yong et al. highlighted wide ranges in the numbers of cases in different series, the variability in selection criteria, the number of nerves involved, the technical modalities, and the possible associated orthopedic procedures. The methods of evaluation and lengths of follow-up also varied greatly.
With regard to the flexor digitorum superficialis (FDS) and flexor digitorum profundi (FDP) motor branches, our anatomic studies suggest that HSN is not feasible without harming the muscles. Therefore, we do not recommend HSN for the digital flexors and instead favor tendon-lengthening procedures.
The phenomenon by which selective neurectomy relieves spasticity without reducing the strength of the target muscles seems linked to the presence of two different components of motor nerves. These are a motor efferent component, which tends to regenerate by sprouting (“neurotization”) after a partial section, and an afferent component (fibers Ia and Ib), the interruption of which leads to the disappearance of spasticity without orderly regrowth. ,
Surgery is only one element of the rehabilitative care of patients. A careful clinical examination and local chemodenervation are required to select the proper candidates for partial neurectomy. Although several variations of selective neurectomy exist, our results of HSN in spasticity of the upper limb have been promising, showing effective reduction of spasticity and improved motion without any loss of strength. These results have remained stable in the medium-term. We hypothesize that the increase in strength of the antagonist muscles, through rebalancing of forces, contributes to the stability of the results. Extended follow-up will be necessary to evaluate the long-term outcomes of this procedure.
Surgery of the spastic shoulders (Nadine Sturbois-Nachef)
The most frequent shoulder problems are adduction and medial rotation deformities. They generally involve the main medial rotator and adductor muscles, i.e., pectoralis major, latissimus dorsi, teres major, and subscapularis. Extension deformities of the arm are less regularly observed and are often related to hypertonia of the main extensor muscles, i.e., latissimus dorsi, teres major, posterior head of the deltoid, and long head of the triceps brachii.
Less frequently, lateral rotation and abduction deformities are observed. They are more regularly found in children, correlated with hyperactivity of the lateral rotator muscles (infraspinatus, teres minor, posterior head of the deltoid) and the abductor muscles (mainly the deltoid).
Surgical goals
The spastic shoulder can cause many problems. In addition to spontaneous or mobilization pain in the shoulders with multiple and often interrelated causes, the request for correction may concern ease of dressing, hygiene, and aesthetics. In functional limbs, the shoulder may limit the positioning of the hand in space and hinder prehension. It is then necessary to restore a balance among the various muscle groups of the shoulder.
Surgical methods
Selective or hyperselective neurectomy.
All the main muscles of the scapulohumeral joint are accessible for selective neurectomy or HSN ( Figs. 33.9 and 33.10 ). Some, however, have multiple innervations or anatomical variations, which lead to incomplete or transient results, not to mention the technical difficulties inherent to the very deep localization of these muscles or their motor nerves. This is the case for the pectoralis major and especially for the subscapularis, which is deep and has multiple innervations. Ouattara et al. found an average of 3.3 motor nerves for the subscapularis, with an average of five entry points located medial to the scapular notch and 3 cm from the anterior edge of the glenoid cavity. Cho et al. reported innervation not only from the superior and inferior subscapular nerves but also from the axillary nerve in 4 of the 10 dissected specimens and from the thoracodorsal nerve in 2 of the specimens.
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