Spinal morphine in nonmalignant chronic pain: a retrospective study in 39 patients

Severe urinary retention secondary to intrathecal morphine pain pump: A case report

Intrathecal opioid pain pumps (IPP) are sometimes prescribed for treatment of chronic nonmalignant pain. Severe urinary retention is not a commonly reported side effect of the IPP. In this case, an elderly female with multiple comorbidities presented with acute onset of severe urinary retention immediately following morphine IPP placement for chronic peripheral neuropathy. Multiple management strategies for urinary retention were employed. However, the urinary retention only fully resolved once the IPP was disabled. This case highlights the need to closely monitor chronic pain patients with complex medical histories who may be uniquely predisposed to opioid-mediated severe urinary retention.

Long-term opioid management for chronic noncancer pain

BACKGROUND

Opioid therapy for chronic noncancer pain (CNCP) is controversial due to concerns regarding long-term effectiveness and safety, particularly the risk of tolerance, dependence, or abuse.

OBJECTIVES

To assess safety, efficacy, and effectiveness of opioids taken long-term for CNCP.

SEARCH STRATEGY

We searched 10 bibliographic databases up to May 2009.

SELECTION CRITERIA

We searched for studies that: collected efficacy data on participants after at least 6 months of treatment; were full-text articles; did not include redundant data; were prospective; enrolled at least 10 participants; reported data of participants who had CNCP. Randomized controlled trials (RCTs) and pre-post case-series studies were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted safety and effectiveness data and settled discrepancies by consensus. We used random-effects meta-analysis' to summarize data where appropriate, used the I(2) statistic to quantify heterogeneity, and, where appropriate, explored heterogeneity using meta-regression. Several sensitivity analyses were performed to test the robustness of the results.

MAIN RESULTS

We reviewed 26 studies with 27 treatment groups that enrolled a total of 4893 participants. Twenty five of the studies were case series or uncontrolled long-term trial continuations, the other was an RCT comparing two opioids. Opioids were administered orally (number of study treatments groups [abbreviated as "k"] = 12, n = 3040), transdermally (k = 5, n = 1628), or intrathecally (k = 10, n = 231). Many participants discontinued due to adverse effects (oral: 22.9% [95% confidence interval (CI): 15.3% to 32.8%]; transdermal: 12.1% [95% CI: 4.9% to 27.0%]; intrathecal: 8.9% [95% CI: 4.0% to 26.1%]); or insufficient pain relief (oral: 10.3% [95% CI: 7.6% to 13.9%]; intrathecal: 7.6% [95% CI: 3.7% to 14.8%]; transdermal: 5.8% [95% CI: 4.2% to 7.9%]). Signs of opioid addiction were reported in 0.27% of participants in the studies that reported that outcome. All three modes of administration were associated with clinically significant reductions in pain, but the amount of pain relief varied among studies. Findings regarding quality of life and functional status were inconclusive due to an insufficient quantity of evidence for oral administration studies and inconclusive statistical findings for transdermal and intrathecal administration studies.

AUTHORS' CONCLUSIONS

Many patients discontinue long-term opioid therapy (especially oral opioids) due to adverse events or insufficient pain relief; however, weak evidence suggests that patients who are able to continue opioids long-term experience clinically significant pain relief. Whether quality of life or functioning improves is inconclusive. Many minor adverse events (like nausea and headache) occurred, but serious adverse events, including iatrogenic opioid addiction, were rare.

Programmable intrathecal opioid delivery systems for chronic noncancer pain: a systematic review of effectiveness and complications

OBJECTIVES

We conducted a systematic review of the literature on the effectiveness and complications of programmable intrathecal opioid and ziconotide drug delivery systems (IDDS) for patients with chronic noncancer pain.

METHODS

We searched MEDLINE, Cochrane, and other bibliographic databases to identify English-language journal articles reporting programmable IDDS complications or effects on pain or functioning. Additional study methodology criteria were applied for the effectiveness review. Two authors independently abstracted data from each included article.

RESULTS

Six articles met the inclusion criteria for the effectiveness and complications reviews, and 4 others met the criteria only for the complications review; none were randomized trials or of ziconotide. All 6 articles reviewed for effectiveness reported improvement in pain and functioning on average among patients who received a permanent IDDS. Two articles reported the proportion of patients with > or =50% improvement in pain at 6 months (38%, 56%) and 2 at longer follow-ups (30%, 44%). Intrathecal morphine-equivalent doses increased over time. The most commonly reported permanent IDDS drug side effects were nausea/vomiting (mean rate weighted by sample size=33%), urinary retention (24%), and pruritus (26%). Catheter problems were also reported commonly. Rare but serious complications included intrathecal catheter tip granulomas.

CONCLUSIONS

The studies reviewed found improvement in pain and functioning on average among patients with chronic noncancer pain who received permanent IDDS. However, their methodologic limitations preclude conclusions concerning the effectiveness of this technology long-term and as compared with other treatments. Drug side effects and hardware complications were common. Suggestions are made for methodologic improvements in future studies.

Drug Delivery Systems

Intrathecal drug delivery (IDD) is a proven and effective treatment alternative in carefully selected patients with chronic pain that cannot be controlled by a well-tailored drug regime and/or spinal cord stimulation (SCS), and may be specifically trialed in patients who fail to respond to SCS. While the lack of randomized controlled trials is often perceived as a limitation of IDD, many studies attest to the efficacy of this therapy, and a number are large-scale and with follow-up periods of up to five years. Good to excellent pain relief is achieved in many patients who have failed more conservative therapies, and there is often a reduced need for analgesia. The advent of patient-controlled analgesia allows flexibility of dosing according to the patient's needs. Consequently, quality of life improves in many patients and the majority express satisfaction with treatment. Some patients are able to return to work. The benefits of IDD (including a potent analgesic response with a more stable therapeutic drug level, decreased latency, increased duration of action, and decreased pharmacological complications) mean that side effects such as nausea, vomiting, sedation, and constipation are reduced. In addition, IDD demonstrates long-term cost-effectiveness when compared to conventional pain therapies, addressing a concern that affects many physicians in clinical practice today.

Intrathecal medication delivery

This brief review of intrathecal pain medication delivery has emphasized the unusual but useful pharmacology of CSF drug delivery, the new study definitely showing that the method is helpful in cancer pain, and the rare complication of mass formation at the catheter tip. As new medications are developed for intrathecal delivery, this field is likely to expand, especially if a wider range of dorsal horn receptor mechanisms underlying pain processing can be modified. The changes in spinal cord signaling that are induced by chronic pain states are being investigated, and new possibilities for intervention are likely. the availability of a reliable well-understood way of delivering such new therapies by implanted drug pumps will speed the process. Intrathecal morphine for chronic pain has an important role in helping many patients with a wide variety of pain conditions and, as with all pain treatment, is woefully underused.

Psychologic evaluation for patients undergoing neuroaugmentative procedures

Neuroaugmentative and neuromodulation therapy continues to expand. New applications are being found for existing technology, such as the use of SCS therapy in the treatment of head pain. The potential impact of existing therapies is enhanced by new discoveries as exemplified by the availability and demonstrated efficacy of different pharmacologic agents and combinations of agents in intrathecal therapy [39]. Increased attention is being paid to cortical stimulation, including motor cortex stimulation and deep brain stimulation. We must, however, not let our fascination for gadgets betray sound sense. The role of psychosocial factors in the outcome of more "objective" and measurable problems, such as spasticity and tremor versus pain, remains an open area of investigation. Although psychologic issues may not be as prevalent in the amelioration of such problems, they may influence the patient's overall level of satisfaction with the therapy and improvement in quality of life.