Baclofen is a muscle relaxant medication used to modulate spasticity and dystonia of cerebral or spinal origin. It is a gamma-aminobutyric acid (GABA) derivative which binds to presynaptic GABA B receptors within the brainstem, dorsal horn of the spinal cord, and other CNS sites.
This binding inhibits the release of excitatory neurotransmitters (glutamate and aspartate) from afferent terminals, primarily by inhibiting calcium uptake required for their release. Baclofen depresses both monosynaptic and polysynaptic reflexes by blocking release of neurotransmitters, and inhibition of overactive stretch reflexes.
It can be taken orally or via the intrathecal space. A tiny intrathecal dose is sufficient compared to the oral dose, removing the medication side effects that often make oral baclofen intolerable at the doses needed for adequate treatment of spasticity.
About the pump system
The infusion system consists of three parts:
- The pump (size of a hockey puck, about 2.5cms thick, weighing 180g). This is surgically implanted under the skin on the abdomen. The pump delivers a controlled amount of baclofen to provide a continuous infusion. It is also possible to have additional boluses at specific times of day (e.g. early morning when stiffness may be worse).
- A catheter which carries the drug from the pump reservoir to the spinal cord.
- The control system. This is a hand held telemetry device which allows for changes in drug dosing by placing the device over the skin where the pump is implanted. To refill the pump, a nurse will place a needle directly into the pump reservoir and inject baclofen.
Benefits of ITB treatment
Extensive literature now supports the efficacy of Intrathecal Baclofen (ITB). It has been in use for the treatment of spinal and cerebral origin spasticity since the early 1990’s. In the literature, ITB™ therapy has been shown to reduce spasticity (as measured by the Ashworth scale) and for some spasticity-causing conditions, decrease the frequency of spasms (as measured by the spasm frequency scale). The improvement has been both clinically and statistically significant.
The positive outcomes of delivering baclofen intrathecally include:
- Increased quality of life, activities of daily living, and level of functioning.
- Clinically and statistically significant reduction in spasticity of cerebral and of spinal origin.
- Reduction of hospitalisations, contractures, oral antispasmodics, nursing/caregiver time
Patients vary in their sensitivity to intrathecal baclofen. The most commonly observed adverse events include hypotonia, somnolence, dizziness, paresthesia, nausea, vomiting, headache, constipation, convulsions, and urinary retention. Problems which are device-related include catheter and occasionally pump dysfunctions or infection.
Suitability and eligibility
At present, our program considers children with severe spasticity and/or dystonia in whom oral anti-spasticity agents, including baclofen, are not effective or not well tolerated.
Goals for therapy may relate to improvement in comfort, easier care and positioning, and lessening joint deformity.
Specific criteria for consideration to the ITB programme include:
- Severe spasticity and/or dystonia that significantly impacts upon quality of life
- Age: > 4 and before 16th birthday
- Weight > 15 kg; adequate trunk length (ie: to fit pump)
- Goals related to care and comfort, for example, tolerating sitting in wheelchair, ease of transfers, reducing pain during nappy changes
- Nutritionally sound
- All other spasticity management options previously explored
- Has trialed oral Baclofen
- Family commitment to programme
Children will be thoroughly assessed in all areas in a decision-making pathway before proceeding with ITB therapy. It may be deemed inappropriate by medical staff, therapists or the family at any stage of this pathway.
As with any implanted device, there are risks and the program will include a significant amount of education for the child, their family and other people involved in their care (e.g. paediatrician, GP, school, respite carers).
About the program
At the initial appointment with a family, doctors and therapists will determine if the child could benefit from ITB and that the family are well informed and are happy to continue.
If so, another appointment will be arranged for a test dose of baclofen given intrathecally by lumbar puncture to establish evidence of reduced spasticity.
If successful, at a later date, the child will be admitted for seven days for ITB pump implantation surgery. A pump is placed subcutaneously with a catheter into the intrathecal space by a paediatric neurosurgeon and baclofen released at a programmed rate, either constant or variable. Pump refills occur on average every 3-6 months. This will be the responsibility of our team or identified, trained doctors outside of the Brisbane area.
Each of these stages involves careful goal setting with the families and community teams, formal muscle testing and may involve a variety of other assessments/outcome measures.
Initially, ongoing reviews will occur frequently until the appropriate therapeutic dose is attained. Formal review will then occur at 6 and 12 months post pump insertion and annually from then on.
Depending on appropriateness, any of the outcome measures below could be used:
- Care and Comfort Hypertonicity Questionnaire
- Canadian Occupational Performance Measure
- Video of goal areas
- Passive range of movement (modified Tardieu scale)
- Active movement (selective motor control)
- Modified Ashworth Scale
- Barry-Albright dystonia scale / Dyskinesia Impairment Scale
- Spasm Scale
- GMFM 88 or 66
- Pain scale
- Cerebral Palsy Quality of Life Measure
If you require any further information on any of the measures, please contact us.
Post-operative guidelines and precautions
There are detailed guidelines post-operatively, but the main ones to be aware of include:
- Children to lie flat for 72 hours post pump insertion to prevent spinal headache.
- Children to commence prone lying (on neurosurgeon’s instructions) around Day 3.
- Head of bed elevated (on neurosurgeon’s instructions) around Day 4
- Child to sit out of bed (on neurosurgeon’s instructions) around Day 6
- Usually discharged between 1-2 weeks following surgery.
- There are two incisions to be aware of post operatively: one on the abdomen and one at the midline of the back.
- An abdominal binder is to be worn for the first six to eight weeks to provide support over the pump area (this will be provided).
- Child is able to commence Aquatic Physiotherapy once wounds healed / on neurosurgeon’s clearance (usually around 6-8 weeks).
- Recommence regular therapy programme on advice of ITB team.
During therapy the following precautions are to be taken:
- Avoid prone positioning where there is concentrated pressure directly over the pump site, for example, over a bolster or therapy ball.
- Avoid rapid or forceful trunk rotation (both active and passive) to reduce the risk of dislodging the catheter, particularly during the first twelve weeks. Instead, logroll the patient for turns.
- Avoid doing straight leg raises or aggressive hamstring stretches for six weeks.
- Avoid rapid or forceful trunk extension, as this may pinch the catheter between bony elements of the spine.
- Spa/hot tubs are permitted to be used for up to ten minutes at a time. Remember that many hot tubs can breed infections.
- Please notify the parents immediately if the child has a temperature.
The therapists involved with the child will discuss any specific guidelines/precautions as relevant along the pathway. We welcome your feedback at any time.
The role of our therapy team
- Identify appropriate candidates for ITB.
- Initial and ongoing assessment / review including feedback to medical staff regarding the need for and/or effects of changes in Baclofen dosage.
- Acute post-operative care while a child is an inpatient at Queensland Children’s Hospital.
- Discharge planning.
- Review equipment (e.g. orthoses, seating) relevant to ITB therapy/goals.
- Casting/splinting as relevant to ITB therapy / goals.
- Liaison with local therapy teams
- Provide post ITB pump insertion therapy (if indicated) to families living within Brisbane metropolitan area, including referral for aquatic physiotherapy when appropriate or indicated by goals.
Local therapy team involvement
The child’s local therapy team can provide valuable information to the ITB team throughout the assessment and review phases of treatment, such as:
- Goals for ITB
- Results of any assessments or previous interventions trialled with the child
- Current physical status
- Feedback on family/child’s potential to cope/comply with ITB program
- Impact of the ITB pump on goal areas and general physical status
- Concerns about efficacy (e.g. increased stiffness observed)
- Need for dosage changes to coincide with changes to a child/family’s routine
Local therapists are encouraged to contact the team at any time with questions, concerns or information that might be relevant to management of the pump.
Queensland Paediatric Rehabilitation Service
Queensland Children’s Hospital
Level 6, 501 Stanley Street, South Brisbane 4101
t: 07 3068 2950
t: 07 3068 1111 (general enquiries)
f: 07 3068 3909
In an emergency, always call 000.
If it’s not an emergency but you have any concerns, contact 13 Health (13 43 2584). Qualified staff will give you advice on who to talk to and how quickly you should do it. You can phone 24 hours a day, seven days a week.