Intrathecal baclofen for spasticity-related pain in amyotrophic lateral sclerosis: efficacy and factors associated with pain relief

Clinical signs and symptoms of spasticity include hypertonia, involuntary movements (spasms, clonus), decreased range of motion, con-tractures, and often spasm-related pain. When spasticity is refractory tomedical management, patients may be referred for intrathecal baclofen (ITB)pump placement. We reviewed a cohort of amyotrophic lateral sclerosis(ALS) patients with intractable spasticity requiring ITB to further define theimpact of ITB on pain relief in this patient population. From 2003 to 2005,eight patients (mean age 43.8 years; 5 men, 3 women) with ALS receivedITB for pain associated with intractable spasticity at our institution. Meandisease duration preoperatively was 47.4 months, mean follow-up was 9.8months, and pain was evaluated using a 0 –10 scoring system. All patientsexperienced spasticity relief in response to a preoperative bolus test injec-tion of ITB (25–50 ␮g) via lumbar puncture. Following ITB pump placement,the average reduction of pain was 54% (P ϭ 0.0082). Six patients (75%)experienced pain score reduction, three of whom had complete pain relief.
Postoperative pain reduction was predicted by the degree of pain reductionfollowing preoperative ITB test injection. These results support ITB as atreatment modality for pain associated with spasticity in ALS.
Muscle Nerve 37: 396 –398, 2008
INTRATHECAL BACLOFEN FOR SPASTICITY-RELATED
PAIN IN AMYOTROPHIC LATERAL SCLEROSIS:
EFFICACY AND FACTORS ASSOCIATED WITH
PAIN RELIEF
SHEARWOOD McCLELLAND III, MD,1 FRANCOIS A. BETHOUX, MD,2 NICHOLAS M. BOULIS, MD,3
MATTHEW H. SUTLIFF,2 DARLENE K. STOUGH,2 KATHLEEN M. SCHWETZ,2
DANUTA M. GOGOL,2 MICHELLE HARRISON,2 and ERIK P. PIORO MD, PhD2
1 Department of Neurosurgery, University of Minnesota Medical School, Mayo Mail Code 96, 420 Delaware Street SE, Minneapolis, Minnesota 55455, USA 2 Department of Neurology, Cleveland Clinic Foundation, Cleveland, Ohio, USA3 Department of Neurosurgery, Cleveland Clinic Foundation, Cleveland, Ohio, USA Spasticity results from the absence of inhibition of
ness.2 Although such pain is usually adequately con- alpha or gamma motor neurons.9 This loss of inhi- trolled with medication and physical therapy, some bition results in involuntary muscle contraction that patients are refractory to treatment or experience causes stiffness interfering with movement, speech, dose-limiting side-effects.6 For this subpopulation, and locomotion.11 Common clinical manifestations an implantable intrathecal baclofen (ITB) pump include hypertonicity, clonus, fixed joints, and may provide adequate pain relief for an otherwise spasm-related pain.3–5,10 Symptoms can present ei- untreatable condition.1 We reviewed a cohort of ther intermittently or continuously, and are often amyotrophic lateral sclerosis (ALS) patients with in- tractable spasticity requiring ITB to define the im- The initial treatment modalities for these symp- pact of ITB on pain relief in this patient population.
toms involve stretching exercises and medications toreduce the pain associated with spasms and stiff- Patient Selection/Demographics.
Abbreviations: ALS, amyotrophic lateral sclerosis; ITB, intrathecal baclofen
this analysis came from the Mellen Center Intrathe- Key words: amyotrophic lateral sclerosis; intrathecal baclofen; pain relief;
spasticity
cal Baclofen registry. This registry was approved by Correspondence to: S. McClelland; e-mail: mccl0285@umn.edu
the Cleveland Clinic Institutional Review Board. Pa- tients were selected by physicians specialized in treat- Published online 25 September 2007 in Wiley InterScience (www.interscience.
wiley.com). DOI 10.1002/mus.20900 ing ALS and spasticity on the basis of a history of severe and intractable ALS-associated spasticity de- not receive adequate relief of spasticity following test spite optimal medical treatment. Optimal medical injection did not undergo pump implantation.
treatment consisted of aggressive oral medicationtrials (usually baclofen, tizanidine, or both), and had Operative Techniques.
led to lack of symptom relief at high doses or to implanted with an ITB pump via standard percuta- dose-limiting side effects (usually sedation). The ex- neous placement technique under general endotra- pected duration of life for each patient was discussed cheal anesthesia. The pump (Medtronic, Minneap- by staff of the ALS clinic and spasticity clinic. Can- olis, Minnesota) was typically filled with 500 ␮g/cm3 didates for ITB therapy were carefully preselected of baclofen prior to implantation. Fluoroscopy was among patients who exhibited slower disease pro- used to pass the distal catheter through the L2–3 gression and predominant upper motor neuron fea- interspace to the T9 –10 interspace in patients with tures in addition to medically refractory spasticity.
spastic lower extremities, and T4 –5 in patients with Because patients with predominantly upper motor associated upper-extremity spasticity. Insertion of neuron features typically have a slower disease pro- the pump was through a 5-inch abdominal incision gression with longer survival, the presence of made lateral to the umbilicus down to the rectus marked spasticity essentially self-selected those pa- fascia. After implantation, the pump was pro- tients with expected longer survival.
grammed based on the total volume of the catheter All patients who were considered good candi- system, after which the patient was placed in an dates for implantation underwent a test injection of abdominal binder and kept flat for 24 hours.
intrathecal baclofen (either 25 or 50 ␮g) in ouroutpatient clinic, with 25 ␮g the preferred dosage Postoperative
for ambulatory patients. Following successful test in- were transferred to an inpatient rehabilitation unit jection (defined as reduction/relief of spasticity), before returning home with continuing outpatient patients were referred to the Cleveland Clinic Foun- or in-home rehabilitation. Patients were subse- dation for programmable intrathecal infusion system quently followed by a team including neurologists, implantation. Only one patient had lack of pain physical therapists, nurses for ITB pump adjustments relief with the test injection; however, because theprimary endpoint for pump implantation was spas- and refills, and the implanting neurosurgeon. Post- ticity relief rather than pain relief following test in- operative pain relief was quantified with the same jection, he went on to undergo surgery as spasticity 0 –10 scoring system used preoperatively. Mean fol- improved following test injection. All ITB pump im- plantations were performed by a single surgeon(N.M.B.).
From January 2003 through December 2005, pro- Following ITB pump placement, the average pain grammable ITB pumps were implanted in eight ALS score was 3.56 (range 0 – 8), a statistically significant patients (five men, three women) with intractable reduction of 54% from preoperative scores (two- spasticity and related pain. The age range was 33–77 tailed t-test; P ϭ 0.0082; GraphPad Software, San years, and the mean age at surgery was 43.8 years.
Diego, California). No patient experienced neuro- ALS symptom duration ranged from 14 to 108 logic morbidity or mortality, or any decline in respi- months, with an average of 47.4 months at surgery.
Pain was quantified by patient response to a physical ratory function, even those patients with higher cath- therapist using a 0 –10 scale, with 0 representing no eter tip placement (T4 –5). Six patients (75%) pain and 10 representing maximal pain. Complete experienced reduction of preoperative pain scores, pain relief was defined as a zero score on the pain three of whom had complete pain relief (postoper- scale. The mean modified preoperative pain score ative pain score of 0). The degree of pain score was 7.69, ranging from 6 to 10, and the degree of reduction following preoperative ITB test injection pain relief following preoperative ITB test injection was predictive of the degree of postoperative pain was recorded in seven of the eight patients (87.5%); reduction following ITB implantation in six of the these data were unavailable for the one patient. The seven patients with recorded preoperative ITB test success of the test injection of ITB was not only injection results (Table 1). Of the three patients who judged based on relief of spasms and spasm-related experienced complete postoperative pain relief, two pain, but also on spastic hypertonia reduction and had preoperative ITB test injection pain scores re- improvement of ease of movement. The mean pre- corded, and in both complete pain relief following operative Ashworth score was 2.93. Patients who did test injection (Table 1). All patients survived for Table 1. Pain score comparisons of patients in this study (0 –10 pain score scale).
Results following preoperative ITB test injection were recorded as follows: resolved ϭ 0 pain score; unchanged ϭ no change from pain score prior to testinjection; reduced ϭ reduction in pain score from prior to test injection.
*These data were not available for patient 1 despite intensive chart review. more than 1 year following surgery, and the mean ceptors in the spinal cord in response to chronic postoperative Ashworth score was 1.72.
exposure. Future studies will be needed to elucidatefurther the functional outcomes following ITB DISCUSSION
Our findings in eight patients with ALS indicate that The authors thank Jane Rein and Dr. Stephen J. Haines forinvaluable assistance. Dr. Bethoux received honoraria and re- ITB is an effective and safe treatment modality for search funding from Medtronic, Inc., the manufacturer of the relief of spasticity-related pain, with no postoperative ITB pump used in this patient cohort.
neurologic morbidity/mortality in our population.
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