Improvement in upper extremity function and trunk control after selective posterior rhizotomy

Long-term upper extremity performance in children with cerebral palsy following selective dorsal rhizotomy

PURPOSE

In children with spastic cerebral palsy, selective dorsal rhizotomy (SDR) is conducted to improve lower limb spasticity. Improvements in upper extremity function have also been noted in early follow-up. The purpose of this study was to determine if upper extremity improvements are sustained in the long term.

METHODS

A retrospective review of prospectively collected data on children who underwent SDR was conducted. Quality of Upper Extremities Skill Test (QUEST) scores for dissociated movement, grasp and total scores were compared using repeated measures ANOVA for individual patients at three time points: preoperatively, early post-operatively (≤ 2 years) and late post-operatively (9+ years).

RESULTS

Out of 200+ patients having SDR, 32 had QUEST assessment at all three time points. Significant improvements in QUEST dissociated movement (F = 3.665, p = 0.045), grasp (F = 7.995, p = 0.001) and total scores (F = 9.471, p = 0.001) were found. Pairwise comparisons were significant from pre-operative to early post-operative times for all QUEST scores (p = 0.001, 0.003, 0.001), and this was maintained at late post-operative assessment for grasp and total scores (p = 0.02, p = 0.02). There was no significant change in scores between early and late post-operative assessment time points.

CONCLUSION

Early improvements in upper extremity QUEST total scores are sustained in the long term following SDR.

Therapeutics in the Management of Spasticity

Spasticity is commonly defined as a velocity-dependent increase in tonic stretch re flexes that results from a variety of disorders affecting the brain and spinal cord. Treat ment of spasticity is generally considered when the increase in tone interferes with functional activities, such as positioning, mobility, or daily cares, when it is painful, or when it leads to complications such as contractures or skin breakdown. This re view discusses the pathophysiology of spasticity and details the various treatments avail able, including physical and occupational therapy modalities, use of splints and or thoses, oral and intrathecal medications, nerve blocks, botulinum toxin injections, and orthopedic and neurosurgical interventions.

Clinical outcomes after selective dorsal rhizotomy in an adult population

OBJECT

Selective dorsal rhizotomy (SDR) is a highly effective and well-established surgical tool for correction of lower-extremity spasticity in children with spastic diplegia caused by cerebral palsy (CP). Although the literature demonstrates considerable immediate and long-term functional benefits in children treated with SDR, the effects of SDR on adults with spastic diplegia have not been thoroughly investigated. The purpose of this retrospective study was to examine the objective and subjective clinical outcomes of SDR on an adult population.

METHODS

We reviewed the charts of 21 consecutive adult patients who underwent SDR for treatment of CP-related spastic diplegia between the years of 1989 and 2007. All patients were treated by a single surgeon (T.S.P.) and underwent formal pre- and postoperative physical therapy assessments to examine joint range of motion (ROM), gross motor function measure (GMFM), and muscle tone. The majority of patients (15/21) exhibited preoperative ambulatory independence without an assistive device. Postoperative assessments were performed at 4 months, but most patients (11/21) had longer follow-up periods (mean, 17.6 ± 30.2 months). All patients were assessed with a telephone survey to estimate pre- and postoperative function with the Katz and Lawton Activities of Daily Living (ADL) Scale.

RESULTS

After SDR surgery, patients experienced significant improvements in lower-extremity passive joint ROM (namely, decreases in hamstring and gastrocnemius tightness) as well as in GMFM crawling and kneeling scores. In addition, spasticity in all measured lower-extremity muscle groups was decreased as compared with preoperative levels. On the basis of our patient self-assessments conducted via telephone, each patient demonstrated subjective improvements in ambulatory ability, spasticity, coordination, joint ROM, pain, overall quality of life, and independence. Also, the Lawton total instrumental ADL scale scores were subjectively improved from preoperative levels. We documented no complications, including postoperative sensory deficits, in any of our patients.

CONCLUSIONS

Our experience suggests that SDR can be an effective treatment for CP-related spastic diplegia in ambulatory adults who are unresponsive to medical therapy and should be considered as a therapeutic option in carefully selected patients. Although our study represents the largest series of adult patients with spastic diplegia to date treated with SDR, the data collected will need to be validated in a larger, prospective clinical trial.

Selective dorsal rhizotomies in the treatment of spasticity related to cerebral palsy

RATIONALE

Selective dorsal rhizotomy (SDR) is a surgical technique developed over the past decades to manage patients diagnosed with cerebral palsy suffering from spastic diplegia. It involves selectively lesioning sensory rootlets in an effort to maintain a balance between elimination of spasticity and preservation of function. Several recent long-term outcome studies have been published. In addition, shorter follow-up randomized controlled studies have compared the outcome of patients having undergone physiotherapy alone with those that received physiotherapy after selective dorsal rhizotomy.

MATERIALS AND METHODS

In this account, we will discuss the rationale and outcome after SDR. The outcome is addressed in terms of the gross motor function measurement scale (GMFM), degree of elimination of spasticity, strength enhancement, range of motion, fine motor skills, activity of daily living, spastic hip, necessity for postoperative orthopedic procedures, bladder and sphincteric function, and finally possible early or late complications associated with the procedure.

CONCLUSION

We conclude that SDR is a safe procedure, which offers durable and significant functional gains to properly selected children with spasticity related to cerebral palsy.

Hand somatosensory cortex activity following selective dorsal rhizotomy: report of three cases with fMRI

INTRODUCTION

Selective dorsal rhizotomy (SDR) is an effective treatment for lower extremity spasticity in cerebral palsy. Cortical organization in sensory cortex may be abnormal in cerebral palsy, and deafferentation is known to lead to cortical reorganization in many situations.

METHODS

We used functional magnetic resonance imaging (fMRI) of hand sensory stimulation to determine if the partial deafferentation of the lower extremity sensory system, associated with SDR, led to any alterations in the cortical somatosensory representation for the upper limbs. Three patients with spastic diplegia were studied with blood oxygen level-dependent (BOLD)-fMRI before and after SDR. fMRI during tactile stimulation of the digits of the right hand was used to map hand somatosensory cortex. Comparison of the cortical maps devoted to the hand before and after SDR assessed for cortical reorganization following partial deafferentation of the lower extremity.

RESULTS

In the one patient with upper extremity involvement, the hand sensory representation was markedly enhanced following SDR. In the other two patients, a normal pattern, but with diminished activity, was seen compared with preoperative findings. SDR for lower limb spastic diplegia does not lead to extensive reorganization of cortex dedicated to the representation of the upper limb. An essentially normal pattern of activation was seen both before and after SDR.

CONCLUSION

The relief of attention demands associated with spasticity may explain the modulation in intensity seen after SDR in the patients who exhibited no upper extremity involvement despite lower limb spasticity.

Neurosurgical treatment of spasticity and other pediatric movement disorders

For children whose spasticity and movement disorders are inadequately treated by oral medications and botulinum toxins, neurosurgical procedures are now available to effectively treat spasticity, tremor, and many cases of dystonia. Spastic diplegia can be treated with selective lumbar rhizotomies, which significantly decrease spasticity, increase range of motion, and improve Gross Motor Function Measure scores. Children with spastic quadriparesis and those with secondary dystonia can be treated with intrathecal baclofen, which diminishes both spasticity and dystonia and is associated with improved function and quality of life. Children with primary dystonia and those with tremor can be treated with deep brain stimulation of the internal globus pallidus and thalamus, respectively. Some children with chorea respond to deep brain stimulation. There are no effective neurosurgical treatments for athetosis or ataxia. The effectiveness of neurosurgical treatments of pediatric movement disorders has increased significantly in the past 15 years.

Functional performance following selective posterior rhizotomy: long-term results determined using a validated evaluative measure

Object. Selective posterior rhizotomy (SPR) may result in considerable benefit for children with spastic cerebral palsy. To date, however, there have been few studies in which validated functional outcome measures have been used to report surgical results beyond 3 years. The authors analyzed data obtained from the McGill Rhizotomy Database to determine long-term functional performance outcomes in patients who underwent lumbosacral dorsal rhizotomy performed using intraoperative electrophysiological monitoring.

Methods. The study population was composed of children with debilitating spasticity who underwent SPR and were evaluated by a multidisciplinary team preoperatively and at 6 months and 1 year postoperatively. Quantitative standardized assessments of activities of daily living (ADL) were obtained using the Pediatric Evaluation of Disability Inventory (PEDI). Of 57 patients who met the entry criteria for the study, 41 completed the 3-year assessments and 30 completed the 5-year assessments.

Statistical analysis demonstrated significant improvement in the mobility and self-care domains of the functional skills dimension at 1 year after SPR. The preoperative and 1-, 3-, and 5-year postoperative scaled scores for the mobility domain were 56, 64, 77.2, and 77.8, respectively. The scaled score for the self-care domain increased from 59 presurgery to 67.9, 81.6, and 82.4 at the 1-, 3-, and 5-year postoperative assessments, respectively.

Conclusions. The results of this study support the presence of significant improvements in functional performance, based on PEDI scores obtained 1 year after SPR. The improvements persisted at the 3- and 5-year follow-up examinations. The authors conclude that SPR performed using intraoperative stimulation is valuable in the augmentation of motor function and self-care skills essential to the performance of ADL.

Long-term functional outcome after selective posterior rhizotomy

OBJECT

Selective posterior rhizotomy (SPR) is a well-recognized treatment for children with spastic cerebral palsy (CP). Few investigators have used quantitative outcome measures to assess the surgical results beyond 3 years. The authors analyzed data obtained from the McGill Rhizotomy Database to determine the long-term functional outcome of children who had undergone selective dorsal rhizotomy accompanied by intraoperative electrophysiological monitoring.

METHODS

The study population was composed of children with spastic CP who underwent SPR and were evaluated by a multidisciplinary team preoperatively, and at 6 months and 1 year postoperatively. Quantitative standardized assessments of lower-limb spasticity, passive range of motion, muscle strength, and ambulatory function were obtained. Of the 93 patients who met the entry criteria for the study, 71 completed the 3-year and 50 completed the 5-year assessments, respectively. Statistical analysis demonstrated significant improvements in spasticity, range of motion, and functional muscle strength at 1 year after SPR. The preoperative, 1-, 3-, and 5-year values for the global score of the Gross Motor Function Measure were 64.6, 70.8, 80, and 85.6, respectively. The greatest improvement occurred in the dimensions reflecting lower-extremity motor function, where the mean change was 10.1% at 1 year, 19.9% at 3 years, and 34.4% at the 5-year follow-up review in comparison with the baseline value. This was associated with a lasting improvement in alignment and postural stability during developmental positions, as well as increased ability to perform difficult transitional movements.

CONCLUSIONS

The results of this study support the presence of significant improvements in lower-limb functional motor outcome 1 year after SPR, and the improvements persist at 3 and 5 years. The authors conclude that SPR in conjunction with intraoperative stimulation is valuable for permanently alleviating lower-limb spasticity while augmenting motor function.

Management of upper limb dysfunction in children with cerebral palsy: a systematic review

Effective use of the upper limb can impact on educational outcomes, participation in activities of daily living and vocational options for many children with cerebral palsy (CP). This article presents the results of a systematic review of the literature on the management of upper limb dysfunction in children with CP. The range of management options includes therapies such as physiotherapy, occupational therapy, neurodevelopmental therapy and conductive education; peripheral splinting and casting; focal or generalized pharmacotherapy; and surgery to improve upper limb function or correct deformity. A literature search identified 60 papers, of which four were randomized controlled trials and 44 were prospective studies with objective outcome measures. Principal studies undertaken for each type of treatment and the efficacy of the different types of treatment were critically evaluated. In addition, the current level of evidence for each study was evaluated according to Sackett's (1989) model and ICIDH-2 classification. A close examination of two relatively new treatments for upper limb spasticity, constraint induced movement therapy and botulinum toxin type A (BTX-A) was conducted with reference to more extensive data on the efficacy of BTX-A in the lower limb.

Gentle dorsal root retraction and dissection can cause areflexia: implications for intraoperative monitoring during "selective" partial dorsal rhizotomy

During partial dorsal rhizotomy (PDR), intraoperative dorsal rootlet stimulation often evokes nonreflex, rather than reflex, motor responses that are due to costimulation of adjacent ventral roots. Intraoperative areflexia typically predicts that motor responses evoked by dorsal rootlet stimulation are nonreflexive. The cause of areflexia during PDR is in part due to anesthesia, but other mechanisms are likely to play a role as well. In this study of three consecutive patients undergoing lumbosacral neurosurgery, soleus H-reflexes evoked by tibial nerve stimulation at the popliteal fossa were found to suddenly decline in amplitude following retraction and gentle dissection of the S-1 dorsal root. In one areflexic patient, dorsal rootlet stimulation proximal to the main site of dissection evoked soleus H-reflexes, although they could not be evoked by tibial nerve stimulation. We conclude that the gentle retraction and dissection of dorsal rootlets that occurs during PDR can induce conduction block of reflex afferents. High-intensity dorsal rootlet stimulation distal to the site of conduction block may then evoke not reflex responses, but rather nonreflex motor responses, due to the costimulation of adjacent ventral roots.

Quantifying muscle activity in non-ambulatory children with spastic cerebral palsy before and after selective dorsal rhizotomy

Cerebral palsy is a condition that results in varying degrees of functional deficits. The goal of this study was to develop an objective measure of muscle activity during a prescribed voluntary motor task in non-ambulatory children with spastic cerebral palsy. While performing a simultaneous hip/knee flexion task from the supine position, followed by return to the starting position, electromyographic and kinematic data were obtained from the right leg of eight children before and after selective dorsal rhizotomy and compared with eight age-matched controls. The electromyographic and kinematic data were combined to determine for each muscle of interest (tibialis anterior, soleus, vastus lateralis, biceps femoris) the percentage of the movement cycle for which the muscle was acting concentrically, eccentrically, isometrically or was considered inactive. Averaged over the four muscles, isometric activity decreased by 38% post-op and the time the muscles were inactive increased by 37% following surgery. The percentages of concentric and eccentric activity did not differ significantly between pre- and post-op conditions. Post-operatively, the percentage muscle activity patterns of the children with cerebral palsy more closely resembled that of the control children: averaged across all muscles and contraction types, the difference between the control children and the children with cerebral palsy was reduced by 50% following surgery. This measurement technique indicates promise as a method for quantifying muscle activity during voluntary motor tasks in non-ambulatory children with cerebral palsy.

Selective dorsal rhizotomy: efficacy and safety in an investigator-masked randomized clinical trial

The objective of this single-center investigator-masked randomized clinical trial was to investigate the efficacy and safety of selective dorsal rhizotomy (SDR) in children with spastic diplegia. Forty-three children with spastic diplegia were randomly assigned on an intention-to-treat basis to receive SDR plus physical therapy (PT), or PT alone. Thirty-eight children completed follow-up through 24 months. Twenty-one children received SDR (SDR+PT group) and 17 received PT (PT Only group). SDR was guided with electrophysiological monitoring and performed by one experienced neurosurgeon. All subjects received equivalent PT. Spasticity was quantified with an electromechanical torque measurement device (spasticity measurement system [SMS]). The Gross Motor Function Measure (GMFM) was used to document changes in functional mobility. Primary outcome measures were collected at baseline, 6, 12, and 24 months by evaluators masked to treatment. At 24 months, the SDR+PT group exceeded the PT Only group in mean reduction of spasticity by SMS measurement (-8.2 versus +5.1 newton meters/radian, P=0.02). The SDR+PT group and the PT Only group demonstrated similar improvements in independent mobility on the GMFM (7.0 versus 7.2 total percent score, P=0.94). Outcomes on secondary variables were consistent with primary outcomes. There were no serious adverse events. We conclude that SDR is safe and reduces spasticity in children with spastic diplegia. SDR plus PT and equivalent PT without SDR result in equal improvements in independent mobility at 24 months. SDR may not be an efficacious treatment for children with mild spastic diplegia.

The critical importance of stimulus intensity in intraoperative monitoring for partial dorsal rhizotomy

During partial lumbosacral dorsal rhizotomy (PDR), intraoperative dorsal rootlet stimulation (drs) evokes motor responses, presumed to be reflexes, which are used to select rootlets for section. However, dr stimuli may also costimulate ventral root (vr) and evoke an M rather than a reflex response, the two being distinguishable only by comparison of response latencies after drs at two separate sites. In 15 consecutive spastic cerebral palsy patients undergoing PDR, we asked whether reflex and M responses were distinguishable on the basis of stimulus intensity (SI). For soleus H reflexes evoked by percutaneous tibial nerve stimulation, the SI for reflex afferents was usually subthreshold for exciting motor fibers. Similarly, for nerve roots, reflexes were evoked by drs at SIs generally less than that for M responses evoked by vr stimulation (vrs). In contrast, M responses evoked by drs required SIs that were on average 20 times greater. Finally, costimulation of contralateral vr after ipsilateral vrs occurred at SIs shown to evoke M responses after drs. We conclude that: (1) reflex and M responses evoked by drs are distinguishable on the basis of the required SI; and (2) drs employing SIs greater than required for vrs evokes M rather than reflex responses due to costimulation of ipsilateral and contralateral vr.