Intraspinal Therapy for the Treatment of Chronic Pain: A Review of the Literature Between 1990 and 2005 and Suggested Protocol for Its Rational and Safe Use

Evaluation of Fixed Intrathecal Bupivacaine Infusion Doses in the Oncologic Population

OBJECTIVES

Intrathecal drug delivery systems (IDDS) are an important method of pain control for patients with refractory oncologic pain. Local anesthetics such as bupivacaine have been infused either alone or with opioids. While effective, bupivacaine can cause adverse effects such as numbness, weakness, and urinary retention. This study looks to establish a safe and efficacious fixed bupivacaine dosing algorithm in intrathecal pumps for cancer patients.

MATERIALS AND METHODS

A bupivacaine dosing algorithm was developed using data from 120 previous patients who underwent IDDS placement at Memorial Sloan Kettering Cancer Center. The outcomes were then evaluated for 43 subsequent patients who were treated with bupivacaine IDDS according to our aforementioned algorithm.

RESULTS

Our data show that in patients treated with our bupivacaine guideline, visual analog pain scale scores decreased by 59% and oral morphine equivalence decreased by 70% from the period between IDDS implantation until discharge from the MSKCC hospital. However, 16.3% of our patients had bupivacaine-related side effects.

CONCLUSIONS

For oncological patients, our data and experience support the initiation of intrathecal bupivacaine at the following doses: 5 mg/day for catheter tips in the cervical spine, 8 mg/day for catheter tips at T1-4, and 10 mg/day for catheter tips at T5-8. Given the higher likelihood of adverse effects in catheters at T9-12 and the lumbar spine, we start at 8 mg/day with close follow-up of the patient. Initiating these doses allow our patients to safely reach adequate analgesia faster, with a shorter hospitalization and quicker return to anti-cancer therapy.

Clinical Evidence for Spinal Cord Stimulation for Failed Back Surgery Syndrome (FBSS): Systematic Review

STUDY DESIGN

A systematic review.

OBJECTIVE

A systematic literature review of the clinical data from prospective studies was undertaken to assess the efficacy of spinal cord stimulation (SCS) in the treatment of failed back surgery syndrome (FBSS) in adults.

SUMMARY OF BACKGROUND DATA

For patients with unrelenting back pain due to mechanical instability of the spine, degenerative disc disease, spinal injury, or deformity, spinal surgery is a well-accepted treatment option; however, even after surgical intervention, many patients continue to experience chronic back pain that can be notoriously difficult to treat. Clinical evidence suggests that for patients with FBSS, repeated surgery will not likely offer relief. Additionally, evidence suggests long-term use of opioid pain medications is not effective in this population, likely presents additional complications, and requires strict management.

METHODS

A systematic literature review was performed using several bibliographic databases, prospective studies in adults using SCS for FBSS were included.

RESULTS AND CONCLUSION

SCS has been shown to be a safe and efficacious treatment for this patient population. Recent technological developments in SCS offer even greater pain relief to patients' refractory to other treatment options, allowing patients to regain functionality and improve their quality of life with significant reductions in pain.

LEVEL OF EVIDENCE

N/A.

Interventional options for the management of refractory cancer pain--what is the evidence?

PURPOSE

Pain is the most common symptom in cancer patients. Standard pain treatment according to the WHO three-step analgesic ladder provides effective pain management in approximately 70-90% of cancer patients. Refractory pain is defined as not responding to "standard" treatments. Interventional analgesic techniques can be used in an attempt to control refractory pain in patients in whom conventional analgesic strategies fail to provide effective pain relief or are intolerable due to severe adverse effects. This systematic review aims to provide the latest evidence on interventional refractory pain management in cancer patients.

METHODS

Systematic literature search in Cochrane, EMBASE and PubMed including reviews and randomised controlled trials (RCTs) and non-randomised controlled trials in the absence of reviews.

RESULTS

Neuraxial analgesia may play a role in refractory cancer pain management. Paravertebral blocks decrease the incidence of persistent post-surgical pain after breast cancer. Coeliac plexus blocks improve pain scores in refractory pancreatic cancer pain for up to 4 weeks after the intervention with fewer burdensome side effects as compared to opioids. Cordotomy has mainly been studied in mesothelioma, and the case series suggest possible benefit for pain at the expense of a relatively high risk of side effects.

CONCLUSIONS

Overall, very few RCTs have been conducted on interventional pain techniques. In reality, it is very difficult to undertake large controlled trials for a number of reasons. Therefore, today's best evidence for practice may be from large case series of comparable patients with careful response and toxicity evaluation and follow-up.

Intrathecal midazolam as supplementary analgesia for chronic lumbar pain--15 years' experience

BACKGROUND

The antinociceptive effect of intrathecal midazolam is based on its affecting spinal gamma-amino butyric acid receptors.

OBJECTIVE

To evaluate pain relief in patients with chronic low back pain and failed back surgery syndrome after a single-shot intrathecal administration of midazolam.

DESIGN

A prospective, open-label study.

OUTCOME MEASURES

The analgesic effect was determined using a patient questionnaire during subsequent visits to the pain therapy service. We classified at least a 50% pain reduction with improved quality of life and improved functional condition as a positive outcome.

RESULTS

Between 1995 and 2010, we performed 500 administrations: 227 administrations in 57 male patients and 273 administrations in 69 female patients. We performed 81 administrations for chronic low back pain and 419 administrations for failed back surgery syndrome. The average age of our patients was 50 years (range 28 to 86). The dose administered ranged from 2 to 5 mg of midazolam. The analgesic effect lasted 9.7 weeks on average, ranging from 1 week to 3 years; the most common reported duration was between 4 and 12 weeks (3 months). In 65% of patients, we achieved pain relief lasting 4 weeks or longer; in 13%, the administration provided no analgesic effect at all. The incidence of side effects (drowsiness, nausea, headache, or transient worsening of complaints) was rather low.

CONCLUSION

Intrathecal midazolam is a useful supplement to standard analgesic therapy with opioids, non-opioids, or spinal steroids.

[Spinal granuloma in a patient receiving a spinal infusion of morphine and clonidine]

Patients treated with long-term spinal infusion of high doses of morphine develop a granuloma at the location of the catheter tip. Diagnosis is based on a steady increase in intrathecal morphine dosage after a relatively prolonged period of stability, on the gradual development of neurologic signs and symptoms suggesting radicular or spinal cord compression, and on magnetic resonance images. We describe a man with central neuropathic pain after removal of a tumor. The presence of all 3 of the aforementioned diagnostic criteria led to suspicion of a spinal granuloma.