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What is intrathecal drug therapy?

Intrathecal drug therapy, also known as intrathecal drug delivery (IDD), offers a specialised method for managing chronic pain, particularly when traditional pain management strategies have been ineffective or cause intolerable side effects. This therapy involves delivering medication directly into the intrathecal space around the spinal cord via an implanted pump and catheter system. This direct delivery allows for using much smaller doses of medication than oral intake, significantly reducing the risk of side effects associated with higher doses required by systemic administration​.

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Intrathecal drug therapy delivers medication directly into the intrathecal space around the spinal cord.

How does intrathecal drug therapy work?

Intrathecal drug therapy is a precise method of delivering medication straight to the spinal cord, aiming to manage chronic pain more effectively. This approach leverages the unique anatomy of the spinal cord, encased within the protective layers known as the meninges and surrounded by cerebrospinal fluid (CSF) in a space called the intrathecal space. The technique bypasses the more traditional, systemic pathways of medication delivery, offering several advantages. Medication infused into this fluid can diffuse evenly and reach target areas on the spinal cord effectively.

Here is how intrathecal drug therapy works:

  • Implantation of a programmable pump: a pump is surgically implanted under the skin, typically in the abdomen; this device stores medication and controls its release. It is programmed to deliver the drug at specified rates and times, tailored to the patient’s needs, allowing for flexibility and precision in treatment.
  • Catheter placement: a flexible tube extending from the pump to the intrathecal space is also implanted. It acts as the pathway through which the medication is delivered from the pump into the cerebrospinal fluid.
  • Delivery of medication: by bypassing the digestive system and the blood-brain barrier, medication delivered via intrathecal drug therapy can be more effective at much lower doses, minimising systemic side effects like nausea, dizziness, and sedation often associated with oral medications.

The dosage and delivery rate of the medication can be adjusted remotely using an external programmer. Patients are usually monitored closely to ensure the therapy is effective and safe.

how intrathecal drug therapy works
By delivering medication directly to the intrathecal space, the therapy ensures that the drugs can act quickly and more directly on the spinal cord.

Benefits of intrathecal drug therapy

  • Targeted delivery
  • Reduced medication doses
  • Fewer side effects
  • Improved quality of life
  • Customisable dosing
  • Alternative treatment option for drug-resistant pain
  • Continuous pain relief
  • Reduced dependence on oral pain medications

What conditions can intrathecal drug therapy treat?

Intrathecal drug therapy is utilised in the management of various chronic pain conditions, especially when other treatment modalities have been ineffective or when systemic side effects limit their use. Intrathecal drug therapy can be used to treat the following pain conditions:

  • Chronic back and neck pain: for individuals who have persistent pain in the back or neck areas, especially after surgeries or due to conditions like herniated or slipped discs, intrathecal drug therapy can provide relief by directly targeting the spinal cord’s pain-signalling pathways.
  • Chronic abdominal pain: intrathecal drug therapy has applications in managing visceral pain, including chronic abdominal pain, by delivering pain-relieving medication close to the source of pain signalling.
  • Failed back and neck surgery syndrome (FBSS): patients who continue to experience pain after one or more spine surgeries may find relief through intrathecal drug therapy, addressing pain that has not been alleviated by surgical intervention.
  • Cancer pain: for cancer patients, especially those with pain that is difficult to control with oral medications, intrathecal drug therapy offers an effective alternative, providing significant pain relief and improving quality of life.
  • Complex regional pain syndrome (CRPS): CRPS is a chronic pain condition usually affecting an arm or a leg after an injury or surgery. Intrathecal drug therapy can be beneficial in managing the severe, often debilitating pain associated with CRPS.

Spasticity: though not a pain condition per se, severe muscle spasticity from conditions like multiple sclerosis or spinal cord injury can also be managed with intrathecal drug therapy, using medications that target muscle tone and movement control.

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Chronic back pain can be treated by intrathecal drug therapy.

What results can I expect from intrathecal drug therapy?

After starting intrathecal drug therapy, patients can anticipate several positive outcomes, primarily concerning pain management and overall quality of life. While individual experiences may vary based on the underlying condition being treated, typical results include:

  • Significant pain relief: many patients report a substantial reduction in pain levels, which allows them to participate more fully in daily activities and enjoy a better quality of life.
  • Reduced side effects: compared to oral pain medications, intrathecal drug therapy often results in fewer systemic side effects like nausea, constipation, and drowsiness.
  • Decreased reliance on oral medications: patients may find they rely less on oral pain medications, which can reduce the risk of dependency and other side effects associated with higher doses of these drugs.
  • Improved functioning: with effective pain management, patients often experience improved physical functioning, enabling them to undertake rehabilitation exercises and activities of daily living with greater ease.
  • Customisable treatment: the pump’s programmable nature allows for tailored medication delivery, meaning treatment can be adjusted over time to meet changing needs or respond to the development of tolerance.
  • Trial period indicators: before the permanent implantation, a trial period helps predict how well the therapy will work for the individual, offering an early indicator of the therapy’s potential benefits.

How many intrathecal drug therapy sessions are needed?

Intrathecal drug therapy doesn’t follow the traditional “session-based” treatment model typical of other pain management strategies like physical therapy or regular injections. Instead, it involves a few key stages:

  • Initial consultation and evaluation: this is where your suitability for the therapy is assessed, involving discussions about your medical history, current pain management strategies, and the impact of pain on your quality of life.
  • Trial period: before a permanent device is implanted, you will undergo a trial to see how well you respond to the therapy. This involves temporarily delivering medication through a catheter to the intrathecal space. The trial period’s length can vary but often lasts a few days to a week.
  • Permanent device implantation: if the trial is successful (i.e., you experience significant pain relief), you will proceed to have the pump and catheter system permanently implanted. This is typically done in a single procedure.
  • Follow-up adjustments: after the device is implanted, you will have follow-up appointments to adjust the medication dosage and pump settings as needed. This might require several visits initially, but appointments may be less frequent once the optimal settings are determined.
  • Regular refills: depending on the pump size and your dosage requirements, the pump reservoir will need to be refilled with medication regularly, typically every 1 to 6 months.
  • Ongoing monitoring: regular check-ups are necessary to ensure the system is working correctly and to make any necessary adjustments to the treatment plan.

The specific number of sessions or visits will vary depending on individual response to the therapy, the need for adjustments, and the schedule for medication refills. It is a personalised process tailored to each patient’s needs, designed to provide long-term pain management.

Frequently Asked Questions

The main difference lies in the location of drug administration: epidural administration is into the space outside the dura mater (the outermost membrane surrounding the spinal cord), while intrathecal administration is within the dura mater, into the cerebrospinal fluid​. 

Patients with an implanted intrathecal pump can usually engage in most daily activities. However, they should avoid activities that involve excessive twisting, bending, or stretching to prevent the catheter from dislodging. It is important to follow specific guidelines provided by your healthcare provider.

If the pump malfunctions or the medication reservoir is empty, it is critical to contact your specialist immediately. Symptoms of withdrawal or pain recurrence might indicate a malfunction. Regular check-ups are scheduled to monitor the pump’s function and refill the medication.

Yes, intrathecal drug therapy can be reversed. The pump can be turned off or removed surgically if it no longer suits your needs or if you experience unacceptable side effects. Any changes should be discussed and managed by your specialist to ensure safety.