Investigating the Feasibility of a Modified Quantitative Sensory Testing Approach to Profile Sensory Function and Predict Pain Outcomes Following Intrathecal Baclofen Implant Surgery in Cerebral Palsy

OBJECTIVES

Intrathecal baclofen (ITB) pumps used to manage spasticity in children with cerebral palsy (CP) also improve pain outcomes for some but not all patients. The purpose of this clinical feasibility study was to explore whether a quantitative sensory testing approach could a) be modified and used to subgroup individuals into sensory profiles and b) test whether the profiles were related to postimplant pain outcomes (i.e., pain responsive or pain persistent).

SUBJECTS

A purposeful clinical sample of nine children with CP (mean age = 12.5 years, male = 56%) and complex communication needs participated.

METHODS

A prospective within-subject design was used to measure proxy-reported pain before and after ITB implant. Pain response status was determined by proxy-reported pain intensity change (>50% change in maximum rated intensity). A modified quantitative sensory testing (mQST) procedure was used to assess behavioral responsivity to an array of calibrated sensory (tactile/acute nociceptive) stimuli before surgery.

RESULTS

Seven individuals with presurgical pain had mQST differentiated sensory profiles in relation to ITB pain outcomes and relative to the two individuals with no pain. Presurgically, the ITB pain responsive subgroup (N = 3, maximum rated pain intensity decreased >50% after ITB implant) showed increased behavioral reactivity to an acute nociceptive stimulus and cold stimulus, whereas the ITB pain persistent subgroup (N = 4) showed reduced behavioral reactivity to cold and repeated von Frey stimulation relative to the no pain individuals.

CONCLUSION

Implications for patient selection criteria and stratification to presurgically identify individuals with CP "at risk" for persistent postprocedure pain are discussed.

Intrathecal Baclofen therapy in Germany: Proceedings of the IAB-Interdisciplinary Working Group for Movement Disorders Consensus Meeting

Continuous intrathecal Baclofen application (ITB) through an intracorporeal pump system is widely used in adults and children with spasticity of spinal and supraspinal origin. Currently, about 1200 new ITB pump systems are implanted in Germany each year. ITB is based on an interdisciplinary approach with neurologists, rehabilitation specialists, paediatricians and neurosurgeons. We are presenting the proceedings of a consensus meeting organised by IAB-Interdisciplinary Working Group for Movement Disorders. The ITB pump system consists of the implantable pump with its drug reservoir, the refill port, an additional side port and a flexible catheter. Non-programmable pumps drive the Baclofen flow by the reservoir pressure. Programmable pumps additionally contain a radiofrequency control unit, an electrical pump and a battery. They have major advantages during the dose-finding phase. ITB doses vary widely between 10 and 2000 μg/day. For spinal spasticity, they are typically in the order of 100-300 μg/day. Hereditary spastic paraplegia seems to require particularly low doses, while dystonia and brain injury require particularly high ones. Best effects are documented for tonic paraspasticity of spinal origin and the least effects for phasic muscle hyperactivity disorders of supraspinal origin. Oral antispastics are mainly effective in mild spasticity. Botulinum toxin is most effective in focal spasticity. Myotomies and denervation operations are restricted to selected cases of focal spasticity. Due to its wide-spread distribution within the cerebrospinal fluid, ITB can tackle wide-spread and severe spasticity.

Management of spasticity in children with cerebral palsy

Cerebral palsy is the most common cause of spasticity and physical disability in children and spasticity is one of the commonest problems in those with neurological disease. The management of spasticity in children with cerebral palsy requires a multidisciplinary effort and should be started as early as possible. There are a number of treatments available for the management of spasticity. This article reviews the variety of options available for the clinical management of spasticity.

Long-term follow-up on continuous intrathecal Baclofen therapy in non-ambulant children with intractable spastic Cerebral Palsy

BACKGROUND

Little is known about the long-term effects of Continuous intrathecal Baclofen (CITB) therapy in non-ambulant children with intractable spastic Cerebral Palsy (CP).

AIM

To determine whether short-term beneficial effects of CITB therapy are present at the long-term, and whether caregivers would choose CITB therapy for their child again considering the advantages and disadvantages encountered over the years.

METHODS

Long-term follow-up data were obtained of the children whom had previously participated in a RCT on CITB by the Dutch Study Group on Spasticity. Quality of life (QoL) was assessed by the Child Health Questionnaire (CHQ), current satisfaction with CITB was measured by use of a Visual Analogue Scale regarding previously set treatment goals, functioning in daily living was determined by a questionnaire concerning functioning of the child, and possible detrimental effects of CITB therapy encountered over the years were noted. All data were acquired via interview of the caregivers.

RESULTS

All 17 children of the former trial participated in this study. Previously identified significant positive effects on pain (CHQ 46.8 vs. 74.38, p = 0.002; VAS 2.4 vs. 8.01, p = 0.02), ease of care (VAS 2.0 vs. 7.26, p = 0.00), and mental health (CHQ 67.2 vs. 75.94, p = 0.010) were still present at the end of the trial. Novel significant positive effects were noted at six to nine years follow-up, i.e. significantly improved scores on the Parent Impact - Emotional subscale (CHQ 66.0 vs. 78.2, p = 0.008), Parent Impact - Time subscale (CHQ 68.9 vs. 91.72, p = 0.002), and the Physical Summary (CHQ 17.6 vs. 27.4, p = 0.019) compared to baseline. Ninety-four percent of the caregivers would choose CITB treatment again for their child again.

CONCLUSION

The beneficial effects of CITB are present at the long term and caregiver satisfaction is high.