Spasticity

Spasticity is a condition with an elevation of the muscle tension, which can lead to random movements. It can emerge as a symptom in several disorders, like cerebral paralysis, transverse lesions or multiple sclerosis.
When the spasticity does not cause any inconvenience, it does not require specific treatment; mild cases of spasticity can often be treated adequately with oral medication (dantrium, lioresal or diazapam). In the ideal case, these medications improve the motor control over the muscles, without causing muscle weakness. In approx. 30 % of the patients with severe generalized spasticity, oral medication cannot control the spasticity adequately. Problems that may occur are: trouble with sitting or lying down, difficulties taking care of oneself or making transfers and pain due to high tension of the muscles. For this group of patients there is warm/cold therapy, therapeutic gymnastics, hydrotherapy, vibration therapy, chemical 'motor point' or nerve block, and destructive surgical treatments. In addition, treatment is possible with neuromodulation, where spasmolytics (muscle relaxants) are administered intrathecally in the nervous system. Intrathecal baclofen can offer a solution to many of these treatment-resistant patients.  

Intrathecal baclofen therapy

In this treatment a pump is placed under the skin in the abdomen. A thin catheter is guided subcutaneously to the vertebral column. It is inserted between the vertebra in the intrathecal space, which contains the spinal cord and is filled with fluid. The pump can be filled with baclofen, a drug that is a derivative of the neurotransmitter GABA, which helps against spasticity. The pump delivers this drug exactly at the spinal cord, which is the active site. An important advantage is that general side effects are minimalized. Below, information is given about who is suitable for this therapy and its impact.

Who is intrathecal baclofen therapy for?

Patients with a stable form of severe generalized spasticity (both trunk and limbs), who do not bear oral medication, suffer too many side effects of do not react sufficiently to the maximal dosage and are hindered in there daily life activities due to the spasticity. These patients may be suitable for intrathecal baclofen therapy.

Treatment with a baclofen pump

When a patient has been selected for this therapy, he/she will be invited for a consult with the rehabilitation doctor in order to examine the spasticity. The patient will also receive elaborate information about the treatment. Possible side effects and risks will also be discussed. Subsequently, the patient will receive additional information to take home. This allows patients to read everything carefully and ask questions at the next visit when necessary. This next visit will be with the rehabilitation doctor or the neurosurgeon.
The treatment with intrathecal baclofen follows a three phase treatment program: a test phase, in case of good effects the implantation phase, and the post-operative control phase.
Test phase: during this phase the patient will be hospitalized for several days at the neurosurgery department. A catheter will be inserted intrathecally. The catheter which is led through the skin is used to inject small amounts of baclofen in order to monitor its effects on the spasticity. When the patient reacts adequately to this test treatment, the pump will be implanted. If the results are not conclusive, a prolonged test phase is performed during which the patient will receive baclofen from an external pump. This allows functional tests to be done, i.e. for patients that use the spasticity partially for standing or walking. 
Implantation phase: Under general anesthesia the pump is placed under the abdominal wall and connected to the subcutaneously tunneled, lumbally placed catheter. The operation will take approx. 1 hour. The pump will be filled with baclofen for the first time during the implantation.
Post-operative phase: The patient will be transferred to the rehabilitation department the day after the operation. The baclofen pump can be adjusted. In addition, the physiotherapist or the occupational therapist will pay attention to the new situation of reduced spasms. After hospital release, regular check-ups take place in the outpatient clinic with the rehabilitation doctor for possible adjustments of the administration program and for refilling of the pump. The refill is performed by means of a syringe, which is brought through the skin and a self-sealing silicon membrane into the pump.  

The baclofen pump

Several pump systems for intrathecal baclofen therapy are commercially available. All systems consist of a pump, a catheter and programming equipment. The Synchromed pump system (Medtronic Inc, Minneapolis, MN, USA) is currently the most used system, since the system can be set very precisely, according to the patients requirements. The pump has a diameter of ~8 cm and consists of a reservoir for the drug, a pump mechanism, a battery and a electronic module to control operation. The desired small amounts of baclofen are delivered in the fluid surrounding the spinal cord through the catheter. The settings for the drug delivery are adjusted through a computer from outside the body. After depletion of the battery the pump (not the catheter) will have to be replaced surgically.

Results

Effective results concerning the improvement in daily activitities are reached in more than 90% of the patients! This is independent of the cause or origin of the spinal or cerebral spasticity. The effectiveness of the therapy is also independent of the age and sex of the patient, as well as the duration of the spasticity. Besides an improvement in motor control, secondary advantages include amelioration in daily activities and bladder/bowel control. In addition, the pain as a result of spasticity will often decrease. Through individualized fine tuning, the therapy can lead to a functional improvement in locomotion and subsequently, an improved quality of life.

Adverse events

Intrathecal administration of baclofen for the treatment of spasticity is safe. The baclofen is delivered very locally and lacks therefore the side effects of systemic baclofen, which may occur with oral application. However, risks cannot be ruled out. The risks can be summarized as follows:

As a result of the operation:

• infection,
• temporary headache, as a result of leaking of cerebrospinal fluid,
• septum in the wound area.

As a result of technical problems an increase in spasticity at some point:

• due to clogging or bending of the catheter,
• shifting of the catheter,
• premature battery depletion.  

As a result of the operation:

Cardiac and respiratory problems can emerge as a result of over- and underdosage of baclofen. For this reason, the patient is hospitalized during the initial setting of the pump. Since the body can develop habituation to baclofen, abrupt pump problems can lead to withdrawal symptoms. Patients and their relatives should be aware of this risk.
A detailed description of the risks in using this system is given to the patient during the intake.