Intrathecal Baclofen Pump (ITB) for the Treatment of Spasticity

What is spasticity?

Increased muscle tone and “tight” muscles due to injury within the central nervous system.

Spasticity is a disorder in which muscles become excessively tight and resist movement. Reflexes (for example, the knee-jerk reflex) become exaggerated. It results from an imbalance between “excitation” and “inhibition” in the central nervous system as signals travel to the peripheral motor nerves.

When descending inhibitory pathways from the brain or spinal cord are impaired, motor neurons become overactive. The result is increased tone, spasms, difficulty moving the limbs passively, and—over time—fixed contractures and deformities.

Which conditions can cause it?

A common symptom across many neurological conditions—not a standalone disease.

Spasticity may originate from the brain or the spinal cord. Common causes include:

• cerebral palsy,
• multiple sclerosis,
• stroke and other cerebrovascular injuries,
• traumatic brain injury,
• spinal cord injury (traumatic or degenerative),
• myelitis, spinal cord tumors, and other rare neurological disorders.

In some patients, a degree of spasticity can be “functionally helpful” (for example, aiding upright posture or transfers). When excessive, however, it causes pain, deformities, difficulty with care, and increased risk of pressure injuries.

How does it affect daily life?

Beyond “stiff movement,” it impacts independence, caregiving, and day-to-day function.

Patients—or parents of children with severe spasticity—often describe:

• stiff limbs that do not bend or straighten easily,
• intense spasms, especially at night or triggered by stimuli (pain, transfers, noise),
• pain from joint and muscle “pulling,”
• difficulty dressing, bathing, and transferring from bed to wheelchair,
• skin pressure with risk of pressure sores, irritation, and injury,
• difficulty managing urinary catheters or orthopedic braces.

The goal of treatment is not only “relaxing” muscles—it is improving function (sitting, transfers, care, less pain) and protecting joints over the long term.

What is baclofen and how does it work?

A GABA-B agonist that “down-regulates” spinal cord reflex activity.

Baclofen is a medication that mimics the action of the neurotransmitter GABA at specific receptors (GABA-B) in the brain and spinal cord. It reduces calcium influx at presynaptic terminals—decreasing the release of excitatory neurotransmitters— and increases potassium conductance postsynaptically, stabilizing neuronal membranes.

In practical terms, this means reduced exaggerated reflexes and lower muscle tone. When taken orally, however, high doses are often needed to reach therapeutic levels in the cerebrospinal fluid, which can lead to central side effects (sleepiness, confusion, mood changes).

When is oral therapy not enough?

When spasticity remains severe—or when side effects become intolerable.

First-line management for spasticity typically includes:

• physiotherapy, occupational therapy, and orthopedic bracing,
• oral medications (baclofen, diazepam, tizanidine, etc.),
• botulinum toxin (Botox) injections into selected muscle groups.

Intrathecal baclofen is considered when:

• spasticity remains severe despite the maximum tolerated oral regimen,
• oral therapy causes significant sedation, confusion, or other limiting side effects,
• there are major functional issues (care, pain, sitting balance),
• the patient and caregivers can commit to long-term follow-up and device management.

What is an intrathecal baclofen pump (ITB)?

A small implantable pump that delivers medication directly into the cerebrospinal fluid.

An ITB system consists of:

• an implantable pump with a medication reservoir, placed under the skin—most commonly in the lower abdomen,
• a thin catheter that enters the intrathecal (subarachnoid) space of the spine and delivers baclofen into the CSF.

The pump is programmed externally to provide continuous, slow infusion and/or timed dose adjustments. This approach often achieves equal or better spasticity control with about 1% of the dose required orally, significantly reducing systemic side effects.

Who is a suitable candidate for an intrathecal baclofen pump (ITB)?

Careful patient selection is the key to a successful spasticity-management program.

Ideal candidates include:

• patients with spasticity persisting > 6 months after spinal cord injury, stroke, traumatic brain injury, or cerebral palsy,
• patients who cannot tolerate adequate oral doses of baclofen or other antispastic medications,
• patients with clear functional goals (e.g., easier care, improved sitting, less pain, better sleep),
• families/caregivers willing to attend regular visits for titration and pump refills.

Contraindications include active infection, significant coagulopathy, severe cardiopulmonary instability, allergy to baclofen, and inability to adhere to follow-up and refill schedules.

How are the screening trial and implantation performed?

First a safe “screening test,” then permanent implantation.

Before implantation, a screening intrathecal baclofen trial is typically performed:

• via lumbar puncture, a dose (e.g., 50 μg) is delivered directly into the CSF,
• over the next 8–12 hours, changes in tone, range of motion, caregiving ease, and function are assessed,
• CSF pressure may also be evaluated, as elevated pressure can be a contraindication.

If the trial is successful and side effects are acceptable, implantation is scheduled:

• under general anesthesia, with the patient positioned laterally,
• a small incision is made in the lower back (L3–L4 or L4–L5) and the catheter is placed intrathecally under fluoroscopic guidance,
• the catheter is securely anchored to reduce the risk of CSF leak or migration,
• a pocket is created in the lower abdominal wall and the pump is implanted and connected,
• the pump is filled with baclofen solution and an initial program is set.

Hospital stay is typically 1–3 days. Patients and caregivers are educated about positioning to avoid pressure on the pump and about warning signs of leakage or infection.

What should I expect after implantation?

Gradual dose titration, close coordination with rehabilitation, and clearly defined goals.

After implantation:

• doses are increased gradually over the first weeks to find the “golden balance” between relaxation and function,
• physiotherapy/occupational therapy is essential to capitalize on improved mobility,
• pump refills are typically performed every 1–3 months, depending on dose and reservoir volume,
• we track changes in gait, sitting, pain, transfers, and caregiving needs.

Many patients experience fewer spasms and improved quality of life. Spasticity, however, usually does not disappear completely—the aim is to make it functionally manageable rather than destructive.

What are the side effects and complications of ITB therapy?

Both the medication and the device require ongoing follow-up. Rare but serious events can occur.

Possible baclofen side effects (especially at higher doses) include:

• sleepiness, dizziness, confusion,
• weakness, hypotonia, or overly “loose” muscles,
• nausea, constipation, low blood pressure.

Device-related complications may include:

• CSF leak with headache or pseudomeningocele,
• catheter migration, fracture, or obstruction,
• infection of the pump pocket or meningitis, which may require system removal,
• pump malfunction (rare).

Two particularly important emergencies are baclofen overdose and abrupt withdrawal, discussed in detail below.

What are baclofen overdose and baclofen withdrawal?

Serious emergencies that are largely preventable with structured follow-up and rapid recognition.

Baclofen overdose may occur:

• during refills (if medication is inadvertently delivered outside the pump),
• after a programming error or pump malfunction,
• after an unexpectedly large intrathecal bolus.

Symptoms may include profound drowsiness or coma, severe hypotonia/flaccid weakness, respiratory depression, low blood pressure, bradycardia or tachycardia, and seizures. Immediate hospital evaluation is required, often with ICU-level monitoring, supportive care, stopping the pump, and—when feasible—CSF drug reduction via the device access port or lumbar puncture.

Baclofen withdrawal may occur due to:

• an empty reservoir,
• pump failure or stoppage,
• catheter obstruction, fracture, or disconnection.

Early features include rapid, painful worsening of spasticity and can progress to tachycardia, hypertension, fever, itching, agitation, delirium, seizures, rhabdomyolysis, and multi-organ failure.

Treatment may require:

• urgent restoration of intrathecal baclofen (via lumbar puncture or pump access when possible),
• rapid evaluation and correction of the pump/catheter issue,
• bridge therapy (e.g., benzodiazepines or propofol) when intrathecal dosing is not immediately available.