Clinical Experience with Continuous Intrathecal Baclofen Administration Using an External Pump as a Screening Method for Functional Assessment

Research Article

Phys Med Rehabil Int. Int. 2018; 5(5): 1156.

Clinical Experience with Continuous Intrathecal Baclofen Administration Using an External Pump as a Screening Method for Functional Assessment

Koopman AE¹*, Snoek GJ² and Nene AV2,3

1Roessingh, Centre for Rehabilitation, The Netherlands

2Formely, Roessingh, Centre for Rehabilitation, The Netherlands

3Formely, Roessingh Research & Development, The Netherlands

*Corresponding author: Koopman AE, Roessingh, Centre for Rehabilitation, Roessinghsbleekweg 33, 7522 AH, Enschede, The Netherlands

Received: September 16, 2018; Accepted: October 23, 2018; Published: October 30, 2018

Abstract

Objective: To describe our clinical experience with continuous intrathecal baclofen (ITB) using an external pump as a screening method.

Design: Retrospective medical records review.

Participants: Forty-three patients with disabling spasticity due to different causes treated in our centre between 2002 and 2016.

Interventions: Patients received continuous ITB for 1 to 10 days via an intrathecal catheter connected to an external pump as a screening method.

Outcome Measures: Effect of ITB on spasticity was assessed using Modified Ashworth Score (MAS) or description of functional hindrance resulting from spasms given by the patient, changes in general function, duration of trial, optimal dose of ITB, adverse effects during trial and whether patients received pump implant.

Results: In 4 patients trial was discontinued before effect on spasticity could be determined, in the other 39 patients ITB had a positive effect on spasticity or hindrance due to spasms. Mean MAS before trial was higher than at the end of trial (2.4 versus 0.8, z = - 4.572, p = 0.000). Seven different functions were considered for assessment, number of functions per patient varied. In 34 patients effect on function could be determined. Thirty-one patients received pump implant. Post-lumbar puncture headache was the most frequent adverse effect (44%).

Conclusion: Screening with continuous ITB using an external pump has an important advantage over that with bolus of ITB when assessing effect on function. However, risks of an external pump are higher and its use should be carefully considered. Measures to reduce adverse events should be explored.

Keywords: Baclofen; Intrathecal Injection; Muscle Spasticity; Extra Corporal Pump; Function

Abbreviations

6MWT: 6 Minute Walk Test; 10MWT: 10 Metre Walk Test; ADL: Activities of Daily Living; BBS: Berg Balance Scale; CP: Cerebral Palsy; CSF: Cerebrospinal Fluid; GABA: Gamma-Amino Butyric acid; HSP: Hereditary Spastic Paraplegia; ITB : intrathecal baclofen; MAS: Modified Ashworth Score; MS: Multiple Sclerosis; PGIC: Patient Global Impression of Change; QOL: Quality of Life; SCI: Spinal Cord Injury; SCI-SET: Spinal Cord Injury Spasticity Evaluation Tool; TUG: Timed Up and Go test; UMNS: Upper Motor Neuron Syndrome

Introduction

Spasticity is a common problem in patients with Upper Motor Neuron Syndrome (UMNS). The prevalence ranges from 17-42.6% in stroke [1-3], 60-78% in Spinal Cord Injury (SCI) [4-6] and 40- 84% in Multiple Sclerosis (MS) [7-10]. It can have negative impact on patients’ life in many different ways, including reduced functional independence [2,4,7,10,11] and quality of life (QOL) [9,12-14]. As a consequence, since patients need more support emotionally as well as in daily activities, the caregiver burden increases [15]. In addition, healthcare costs rise due to need for more home care, hospital admissions or specialist referrals [7,15-17].

Treatment of spasticity is only initiated when the spasticity causes severe pain or is disabling, interfering with hygiene, daily care or mobility. Several treatment algorithms have been developed [18,19]. The first step in these treatment algorithms is the correction of trigger factors and physical therapy. If this has no satisfactorily effect, the next step is to make a distinction between focal or general spasticity. Local spasticity can be treated with local denervation of the muscle or nerve or with surgery. Treatment options for general spasticity consist of several oral antispasticity agents, either monotherapy or in case of insufficient effect, in combination with other agents. When these treatments have no or limited effect or when side effects are severe, intrathecal baclofen (ITB) can be considered, for both multifocal and general spasticity.

Treatment of spasticity is only initiated when the spasticity causes severe pain or is disabling, interfering with hygiene, daily care or mobility. Several treatment algorithms have been developed [18,19]. The first step in these treatment algorithms is the correction of trigger factors and physical therapy. If this has no satisfactorily effect, the next step is to make a distinction between focal or general spasticity. Local spasticity can be treated with local denervation of the muscle or nerve or with surgery. Treatment options for general spasticity consist of several oral antispasticity agents, either monotherapy or in case of insufficient effect, in combination with other agents. When these treatments have no or limited effect or when side effects are severe, intrathecal baclofen (ITB) can be considered, for both multifocal and general spasticity.

To determine whether ITB is a suitable treatment for a patient with spasticity or not, a bolus of baclofen is injected via lumbar puncture and its effect on spasticity is monitored. The effect starts after 30 to 120 minutes, is optimal between 4 and 6 hours and lasts between 6 and 8 hours [23]. Assessments of spasticity are carried out before the effect of Baclofen diminishes. In that short period it is challenging to evaluate the effect of ITB on function or on ambulation. In addition, the bolus cannot be titrated and small differences in effect on spasticity cannot be made.

An alternative procedure is to use an external pump to administer continuous ITB. To achieve this, an intrathecal catheter is placed and connected to an external pump, which controls the dose of Baclofen administered. The effect can be evaluated for a longer period of time and the dose can be adjusted. Besides evaluation of expected positive effects, negative effects on function such as transfers, standing and walking could also be observed.

Only 4 studies have described their experience with this screening method before pump implantation. They conclude that an external pump can be used to evaluate effect of ITB on function and walking ability in patients with Hereditary Spastic Paraplegia (HSP) [24], Cerebral Palsy (CP) [25] and patients with different causes of spasticity [26]. The method is also helpful to evaluate effect on the unaffected limbs in hemiparetic spasticity [27]. Three of these studies had a small number of patients, 1 in Heetla et al. [24], 3 in Harned et al. [27] and 7 in Bleyenheuft et al. [25], but Phillips et al. [26] included 57 patients.

The aim of this study is to describe our clinical experience with continuous ITB using the external pump as a screening method and to compare our method and results to that of previous studies.

Methods

All patients who have had an external pump with continuous ITB between 2002 and 2016 as a screening procedure are included in this study. These patients were considered suitable for treatment with ITB, based on clinical evaluation. They were selected for trial with an external pump by rehabilitation physicians of the rehabilitation centre in agreement with neurosurgeons of the local general hospital. Patients were interviewed before the trial to find out which function, in their view, needed to improve or had to remain unchanged. Data was collected retrospectively from medical records. No patients were excluded.

The intrathecal catheters (Perifix® SoftTip) were placed by neurosurgeons or anesthesiologist of the local general hospital. From 2015 catheters were tunnelled under the skin to the lateral side of the patient, in order to make it more secure. The level of the tip of the catheter was determined depending on the level of SCI and desired effect. After placement of the catheter, the patients were directly transferred to the rehabilitation centre where the catheter was connected to the external pump and initial dose was started. Before 2015 this was the Crono five pump, since 2015 the CADD®-Solis pump has been used.

Depending on diagnoses and severity of spasticity, the initial dose was 1 mcg to 4 mcg of baclofen an hour. Oral antispasticity agents were continued. Before starting the pump, spasticity was assessed by rehabilitation physicians using the Modified Ashworth Score (MAS). In case of spasms, the patients were asked whether they caused functional hindrance. After starting the ITB, the assessments were carried out twice a day during trial. Change in functioning was observed by physiotherapists and nurses every day and opinion of the patient regarding the effect of ITB was asked and noted. Based on the combination of these findings the ITB dose was adjusted up to twice a day by the rehabilitation physician, with a maximum increment of 1 mcg/hour each time.

During the trial, patients were monitored for vital functions and side effects such as headaches, nausea, puncture wound problems, CSF leakage and urinary retention. Aimed duration of the trial was no longer than one week. After removing the catheter, patients stayed in the rehabilitation centre for at least one day to continue monitoring. The internal tip of the removed catheter was sent for bacterial examination and patients measured their temperature twice a day for one week after discharge.

Outcome measures were duration of trial, optimal dose of ITB, effect of ITB on spasticity, functional hindrance due to spasms and general function, side effects and complications during trial and whether a pump was implanted or not after the trial.

For each patient relevant muscles, depending on spasticity, were determined and were assessed using MAS. Mean MAS before and at the end of trial was calculated for each patient. Wilcoxon Signed Ranked Test was used to compare the mean MAS before and at the end of trial. When one of the scores was missing for a patient, all scores of this patient were excluded. Analyses were performed with IBM SPSS Statistics 19.

Results

Details of 43 patients included in this study are shown in Table 1. Main causes of spasticity were MS, SCI and CP, the “other’ causes included Primary lateral sclerosis, Metachromatic leukodystrophy and Autosomal Recessive Spastic Ataxia of Charlevoix Saguenay. Two patients had spasticity without a clear origin. Average duration of trial was five days and mean optimal ITB dose was 4mcg/h (Tables 2 & 3).