Intrathecal granuloma complicating chronic spinal infusion of morphine. Report of three cases

Intrathecal drug delivery for the management of pain and spasticity in adults: British Pain Society's recommendations for best clinical practice

The British Pain Society updated their recommendations on intrathecal drug delivery (ITDD) for the management of pain and spasticity in adults. The recommendations are primarily evidence based but where necessary comprise the consensus opinion of the working group. The recommendations are accompanied by information for patients and their carers, intended to inform and support patients in their decision making. The updated guidance includes recent evidence base of ITDD use in pain and spasticity, address the issues of drug pump compatibility following the latest manufacturer and Medicines and Healthcare products Regulatory Agency (MHRA) recommendations as well as provide an update on the indications and complication management particularly endocrine complications and intrathecal granuloma formation.

Symptomatic Intrathecal Catheter Tip Granuloma Formation With Ultralow-Dose and Low-Concentration Morphine Infusion: A Case Report and Review of Literature

OBJECTIVES

This study aimed to describe catheter tip granuloma (CTG) formation in a patient on ultralow-dose, low-concentration morphine via intrathecal (IT) drug delivery system (IDDS) and to review literature for reports of IT granuloma formation and association with drug type, drug dose, and drug concentration.

MATERIALS AND METHODS

This review describes diagnosis and management of a patient with CTG on ultralow-dose, low-concentration morphine. PubMed data base search was conducted from January 1990 to July 2021 for original articles on CTG formation in humans getting intrathecal analgesics. Data were extracted on indications for IDDS, time to detect CTG, and type of drug/s with drug doses and concentrations. Percentages and average with range for age, sex, duration of infusion, drug doses, and drug concentrations were calculated.

RESULTS

We describe CTG formation and spinal cord compression with worsening of sensorimotor deficits in a patient receiving intrathecal morphine at ultralow dose (0.6 mg/d) and low concentration (1.2 mg/mL), which is the lowest reported morphine dose associated with CTG in the literature. Our literature review shows all IT drugs have the potential for granuloma formation, and there is no drug with granuloma-inhibiting effect.

CONCLUSIONS

There is no drug, dose, or concentration that has granuloma-sparing effect. It is imperative to maintain vigilance for potential CTG in all patients with IDDS. Routine monitoring and prompt evaluation for any unexplained symptoms or change in neurologic status from baseline is critical in early detection and treatment of CTG.

Primary Hydromorphone-Related Intrathecal Catheter Tip Granulomas: Is There a Role for Dose and Concentration?

BACKGROUND

Intrathecal drug delivery therapy has been used effectively in treating patients with intractable chronic pain. The development of an intrathecal catheter tip granuloma (ICTG) related to delivery of intrathecal opiates is a relatively infrequent, but potentially devastating complication. While there are many morphine-related ICTG cases described, reports of hydromorphone-related ICTG are limited. In addition, studies suggest a strong correlation between the use of higher doses and concentrations of intrathecal opiates and ICTG formation.

OBJECTIVE

The objective of this study is to determine the incidence and the association of intrathecal hydromorphone dose, concentration, duration of treatment and concomitant agents with ICTG formation.

STUDY DESIGN

This is a retrospective analysis of 101 consecutive patients implanted with intrathecal infusion delivery devices. Data were collected from chart review, and records of pump refills from the division of Pain Medicine of University Hospitals or outsourced to a home pump refill service.

RESULTS

From a cohort of 101 consecutively implanted patients, 69 were treated with intrathecal hydromorphone and followed up postimplant for an average of 33.5 ± 24 months (range 0-93 months; 95% CI of 27-39 months). The incidence of ICTG in our patient population was 8.7% during this period of time postimplant with mean time to granuloma detection 35.1 ± 7.9 months. Patients developing granuloma (n = 6) were treated with a combination of intrathecal hydromorphone and bupivacaine infusion. Exposure time to intrathecal agents was not different between the granuloma and nongranuloma group. Monthly dose increase of hydromorphone was higher in granuloma group vs. non-granuloma group (58 ± 34 mcg/month n = 6 vs. 25 ± 8 mcg/month n = 63). Four out of six granuloma cases occurred with low dose and concentration of IT hydromorphone (160-370 mcg/day; 0.75-1.0 mg/mL concentration). Intrathecal bupivacaine dose was not different between groups. A subset of patients was treated with intrathecal fentanyl and bupivacaine. No intrathecal granulomas occurred in this patient cohort.

CONCLUSION

This is the first clinical report demonstrating an association of hydromorphone with intrathecal granulomas, particularly at low doses and concentrations of hydromorphone. This study supports the notion that using low dose of IT opioids might not protect against ICTG development but that the level of exposure and type of opioid used in IT space might be highly correlated with ICTG development. Further research and recommendations related to chronic intrathecal opioid infusions are necessary to raise awareness of significant incidence of ICTG and development of tests to isolate patient populations at high risk.

Increased spasticity from a fracture in the baclofen catheter caused by Charcot spine: case report

In patients with Charcot spine, a loss of normal feedback response from the insensate spine results in spinal neuropathy. Increasing deformity, which can manifest as sitting imbalance, crepitus, or increased back pain, can result. We present the case of a patient with a high-thoracic spinal cord injury (SCI) who subsequently developed a Charcot joint at the T10-11 level that resulted in a dramatic increase in previously controlled spasticity after fracture of an existing baclofen catheter. The 68-year-old man with T4 paraplegia presented with increasing baclofen requirements and radiographic evidence of fracture of the intrathecal baclofen catheter with an associated Charcot joint with extensive bony destruction. The neuropathic spinal arthropathy caused mechanical baclofen catheter malfunction and resulting increased spasticity. The patient was found to have transected both his spinal cord and the baclofen catheter. Treatment consisted of removal of the catheter and stabilization with long-segment instrumentation and fusion from T6 to L2. Follow-up radiographs obtained a year and a half after surgery showed no evidence of hardware failure or significant malalignment. The patient has experienced resolution of symptoms and does not require oral or intrathecal baclofen. This is the only reported case of a Charcot spine causing intrathecal catheter fracture, leading to increased spasticity. This noteworthy case suggests that late spinal instability should be considered in the setting of SCI and increased spasticity.

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

It was the purpose of this study to retrospectively test the safety and efficacy of the use of intraspinal analgesics in a diverse population of patients with chronic nonmalignant pain. This study was conducted in 39 patients, refractory to conventional therapies for intrathecal therapy. Twenty-two patients had neuropathic pain and 17 had nociceptive pain. The mean follow-up of this patient population was 2.2 years with a range of 36 months to 6.5 years. Analgesia with intraspinal morphine, initial and final dose of intraspinal agents used, stability of morphine dose over time, and side effects and complications with or without bupivacaine and/or clonidine was assessed after 6 months of treatment, and at the end of study. After 6 months, three patients discontinued the study for differing reasons, 28 patients (77.8%) reported excellent results, and five patients (14%) reported good results. One patient reported no pain relief with intraspinal morphine and bupivacaine and five patients reported insufficient or no pain relief. At final assessment, 20 patients (55.6%) reported excellent results with no differences based on pain type or pain syndrome and eight patients (22.2%) reported good analgesia. Morphine doses remained stable throughout treatment, with an average dose of 2 mg per patient. Ninety-one percent of patients were satisfied with the method used and considered it superior to all previous therapeutic techniques tried, improving their quality of life. As for complications, one patient developed a clostridial infection during the immediate postoperative period which required pump removal and one patient developed severe urinary retention requiring system removal. There were three catheter obstructions (two in the same patient) and one catheter disconnection. Other patient-reported side effects were not considered significant by the authors to be mentioned here. After more than 6 years of experience with spinal infusion of morphine, either alone or admixed with other spinal analgesics, in patients with pain of nonmalignant origin, we consider the technique to be helpful in selected patients not responding to oral treatment or when untoward side effects exist with oral treatment. The advantages, as regards to analgesic efficacy and quality of life, clearly outweigh the drawbacks of the long-term use of spinal morphine.

Spinal cord compression secondary to intrathecal catheter-induced granuloma: a report of four cases

Objective: The management of nonmalignant pain by morphine pump implantation has become an effective and increasingly frequent strategy of care. We report a rare complication of intrathecal granuloma formation adjacent to the intrathecal catheter tip resulting in spinal cord compression in four patients undergoing intrathecal treatment for chronic pain.

Methods: Four patients presented with chronic back pain and lower extremity pain and weakness and were treated with morphine pump implantation (Fig 1). Each patient developed a mass at the level of the intrathecal catheter tip resulting in increased back pain and diminished neurological function. Following clinical examination and x-ray workup, the patients underwent surgical resection of the mass and removal of the intrathecal catheter. One patient received conservative saline therapy first, and another patient had granuloma resection first and removal of the intrathecal catheter at a later date. Pathological analysis showed granulation tissue with extensive necrosis and chronic inflammation, with negative culture results. No evidence of neoplasm was found.

Results: Patients showed varying degrees of improvement following removal of the intrathecal mass. Two patients had moderate pain reduction following resection of the granuloma; a third had minimal pain improvement; and a fourth had significant pain improvement but continued lower extremity weakness.

Conclusions: The formation of granulomas caused by intrathecal catheter implantation is a rare but serious complication. Imaging studies including magnetic resonance imaging with contrast and computed tomography with myelogram should be used to follow up a neurological examination consistent with spinal cord compression. Timely surgical intervention may result in marked improvement of symptoms.

A review of intrathecal morphine therapy related granulomas

The development of catheter associated granulomatous masses in intrathecal morphine therapy is an uncommon, but potentially serious problem. While these systems have historically been used in patients with short life expectancies, more recently patients with pain from a benign source have benefited from this therapy, and new complications are being encountered secondary to the patients' longer life spans. Morphine is the most commonly used intrathecal opioid and evidence exists that the formation of granulomatous masses are related to the use of higher doses. When the patients' requirement of morphine increases significantly, the physician should be alert for signs of spinal cord compression, such as new neurological deficits, myelopathy, or radiculopathy. Patients that require these higher doses should be properly informed of the association with granulomas and their associated risks. Indolent infection may also be the etiology of granulomatous masses, and the presence of organisms, both aerobic and anaerobic, should be routinely investigated. Patients with catheter-associated granulomas appear to share several features. They exhibit the onset of symptoms several months following the initiation of intraspinal opioids and commonly present with an increase in pain that precedes signs and symptoms of neurological deterioration. While MRI might be the preferred method of detection of intrathecal granulomas, its cost and availability are prohibitive for routine screening. CT myelogram via pump side port injection of contrast can also be performed to detect catheter tip related granulomas/obstructions. Serial neurological examinations for new deficits may be performed and recorded during pump refill visits to recognize a granulomatous mass in its early stages. If an abnormality is identified, imaging studies are appropriate. Awareness of the condition and vigilance are the keys to successful management of this complication.

Catheter-tip mass mimicking a spinal epidural hematoma

As > 95,000 spinal drug-delivery devices have been implanted since their inception in the 1980s, the recognition of associated adverse effects is essential. Since 1985, numerous reports have described the presence of catheter-tip granulomas. In the current case, the authors describe a less frequent complication of epidural bupivacaine precipitation. Regardless of origin, these unusual lesions have been increasingly recognized as a rare but potentially devastating complication of intrathecal infusions.

A 34-year-old woman with an intrathecal pain-pump delivering fentanyl, bupivacaine, and clonidine for thoracic outlet syndrome presented with rapidly progressive neurological deficits and increasing neck and upper-extremity pain. Neuroimaging disclosed a C7–T1 mass that was thought to be a hematoma that occurred after a recent epidural steroid injection. On emergency surgical decompression by laminectomy, a chalky mass containing viscous fluid was identified surrounding an epidurally located catheter. Histopathological examination revealed a proteinaceous mass consistent with drug precipitate enveloped by fibrosis and mild inflammation. Postoperatively, the patient recovered with minimal neurological deficit. The presentation and clinical relevance are discussed in conjunction with a review of the pertinent literature.

Catheter-tip masses are a rare complication of implantable drug-delivery devices occurring in < 3% of all patients with intrathecal catheters. Regardless of the anatomical site, the most common presenting features are neurological deficits, worsening pain, and increasing requirements for pain medication. Expedient diagnosis and management are essential for physicians treating patients with spinal infusion devices to prevent significant neurological sequelae. Further investigation is warranted regarding the use of bupivacaine as an adjunct in permanent spinal infusion systems.

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.

Stellenwert der intrathekalen Schmerztherapie

Intraspinal drug infusion using implantable pumps and catheter systems is a safe and effective therapy for selected pain patients with severe chronic pain. It improves pain relief, reduces drug-related side effects, decreases the need for oral analgesia and enhances quality of life in a segment of chronic pain patients whose pain has not been controlled with more conservative therapies. Intrathecal drug therapy has therefore established its role in the treatment of malignant pain, benign pain and severe spasticity.Careful patient selection and management as well as a multidisciplinary approach are determinants of successful treatment. Current practices for patient selection and management, screening, drug selection, dosing and implantation for intrathecal drug delivery systems are discussed.

Late bacterial granuloma at an intrathecal drug delivery catheter

In the case reported, neurological complaints were pain and dysaesthesiae in the lower back and thigh, as well as paresis of the ileopsoas muscle. MRI of the lumbar spine showed an intradural-extramedullary mass at the level of L1 homogeneously enhancing with gadolinium. This mass was situated at the tip of an intrathecal catheter implanted 11 years before for a morphine trial infusion as therapy for phantom pain after amputation of the right arm. Now, removal of the catheter was performed. Cultures of lumbar CSF and the catheter tip demonstrated coagulase negative staphylococcus. Antibiotic medication with cephalosporines was given for 6 weeks. After removal of the catheter, the patient was free of pain and he progressively regained full neurological function. Although most catheter-associated granulomas reported so far were sterile in nature, bacterial infection should still be considered even years after catheter placement.

Spinal Cord Compression in a Patient with a Pain Pump for Failed Back Syndrome: A Chalk-Like Precipitate Mimicking a Spinal Cord Neoplasm: Case Report

OBJECTIVE AND IMPORTANCE

The use of intrathecal morphine has been effective with few complications for chronic intractable pain of both benign and malignant origins. A rare but serious problem that exists is the formation of an inflammatory mass at the catheter tip of the pain pump.

CLINICAL PRESENTATION

We report the case of a 67-year-old female patient with failed back syndrome who presented with sensory complaints and back pain.

INTERVENTION

Magnetic resonance imaging revealed impingement on the thoracic cord by a mass. The mass was originally thought to be a spinal cord tumor; however, operation and chemical analysis of the mass showed that it was a bupivacaine precipitate at the tip of the catheter of the pain pump.

CONCLUSION

This is the first such case, to our knowledge, of a bupivacaine precipitate mimicking a spinal cord tumor.

Neurologische Komplikationen und Wirkverlust unter intrathekaler Schmerztherapie

In a new guideline issued by the German Association for the Study of Pain, intrathecal opioid therapy is described as proven to be effective with relatively few side effects. We reviewed this statement by analysis of the available literature and critical evaluation of the clinical course in a few of our own patients (n=3). In these cases (as well as in a further eight patients), explantation and a switch to oral opioids led to distinctly better alleviation of pain and abatement of the unwanted effects. The problems we discuss do not appear to be rare instances, but by all means complications that are frequently described. The long-term efficacy of intrathecal opioids has not been adequately verified; moreover, their potency is not high. The frequency of undesired events is comparable to that of oral opioid medication, but serious neurological complications are possible. To avoid dose escalations and to recognize neurological complications in time, diligent monitoring by the surgeon or an experienced pain center is essential.

Paraplegia Secondary to Progressive Necrotic Myelopathy in a Patient with an Implanted Morphine Pump

We present an individual with chronic low back pain who was treated with an implanted morphine pump, which provided very good pain relief for 16 mos. However, the patient developed acute paraplegia secondary to progressive necrotic myelopathy, a rare form of transverse myelitis. The cause of this patient's neurologic deficit was unclear. Three months after the onset of paralysis, a trial of discontinuation of the intrathecal morphine was performed to exclude the morphine as a reversible cause of paralysis. Within 24 hrs after his pump was depleted, his pain became significantly worse. He was maintained on oral opioids for 6 mos, and his pain was only partly controlled, with a daily average visual analog scale score of 7/10. There was no improvement in his neurologic status after stopping the intrathecal morphine therapy, and several consecutive magnetic resonance images of the spine demonstrated radiologic progression of spinal cord involvement. The patient developed classic opioid side effects of excessive somnolence and constipation. Intrathecal morphine therapy was re-instituted, and the patient reported a significant decrease of his pain, an improvement in quality of life, and no complications related to pump functioning.

Interventional Procedures for Cancer Pain Management: When Are They Indicated?

Non-invasive pharmacological management of patients with cancer related pain has resulted in pain control in 90-95% of the patients. Thus, 5-10% of patients still experience inadequate pain control despite aggressive combined pharmacological therapy. Moreover, patients may not tolerate an aggressive program of titration of medications and fail this approach because of side effects. In these patients interventional techniques have been very useful. This article discusses the alternative therapies, as well as the pitfalls in implementing these therapies, to achieve the highest possible success while minimizing potential complications and side effects.

Chronic inflammatory granuloma mimics clinical manifestations of lumbar spinal stenosis after acupuncture: a case report

STUDY DESIGN

A case report and review of the literature.

OBJECTIVES

To present a case of chronic inflammatory epidural granuloma formed after acupuncture.

SUMMARY OF THE BACKGROUND DATA

A number of cases of complications resulting from acupuncture have been reported, including acute infection, hemorrhage, and direct injury to internal organs or neural tissues. However, to the best of our knowledge, there has been no report of epidural granuloma formed following acupuncture and mimicking clinical manifestations of lumbar stenosis.

METHODS

A 68-year-old woman suffered from low back pain and sciatica aggravated by acupuncture. We reviewed her medical record, imaging studies, microscopic findings of the mass, and related literature.

RESULTS

Microscopic examination revealed the mass as a chronic inflammatory granuloma. From her previous history and imaging study, the mass, which compressed the lumbar forth nerve and dural sac,was highly suspected to have been formed after acupuncture. Surgical decompression and excision of the epidural mass relieved her symptoms.

CONCLUSION

Chronic inflammatory granuloma may be formed as a complication of acupuncture. Under such circumstances, surgical excision of the mass may be an effective way of relieving the symptoms.

Catheter-associated masses in patients receiving intrathecal analgesic therapy

A cohort of seven patients receiving intrathecal analgesic drug therapy for chronic intractable pain underwent radiocontrast myelography and computed tomography (CT) scanning to screen for catheter-associated intrathecal masses. Three of seven patients examined had intraspinal masses associated with the tip of the drug infusion catheter after a total of 118 mo of therapy. The index case presented with exacerbation of neuropathic pain and paralysis of the left lower extremity. The two additional cases detected by CT myelography were asymptomatic at the time the catheter-associated mass was assessed. The mean duration of therapy before diagnosis of the catheter-associated mass was 19.6 mo, with a range of 16-25 mo. An intergroup comparison of demographic and treatment variables between patients, with and without catheter-associated masses, demonstrated that patients with masses were younger and were receiving a larger morphine dose than patients without masses. The differences were statistically significant (P = 0.05). In one patient with an asymptomatic catheter-associated intrathecal mass, regression of the mass was observed after cessation of therapy. In a second asymptomatic patient, the mass remained stable over 1 yr of continued treatment after substitution of hydromorphone for morphine without interruption of therapy. Neither asymptomatic patient has subsequently developed additional neurologic findings or injury after detection of occult catheter-associated intrathecal masses and clinical intervention. We suggest that all patients receiving long-term intrathecal analgesia should undergo periodic radiographic surveillance to further define their risk of developing occult catheter-associated masses and to allow intervention before neurologic injury can develop.

IMPLICATIONS

Catheter-associated intrathecal masses were detected in three of seven patients receiving long-term intrathecal analgesia. In the two asymptomatic patients, timely clinical intervention was associated with the avoidance of subsequent neurologic injury and spontaneous resolution of one of the occult masses.

Predictive Value of Intrathecal Narcotic Trials for Long-Term Therapy with Implantable Drug Administration Systems in Chronic Non-Cancer Pain Patients

This study retrospectively investigated the predictive value of intrathecal narcotic trials for long-term drug utilization via implantable pumps in chronic non-cancer patients. Data were derived from 86 patients who were categorized according to the intrathecal narcotic dose that resulted in the optimal trial response. The response during the trial period and the pattern of long-term utilization of morphine was studied, as was the impact of age, gender and diagnosis. The analysis revealed that low dose responders had lower daily dose requirements at 18 months than standard dose and high dose responders. It also showed that women had lower total daily dose requirements at 18 and 24 months and that individuals over 65 years of age had lower total daily dose requirements at 18 months. A trend toward a disproportionately higher use of adjuvant drugs and narcotic substitutions was found among high dose responders, while a trend toward a disproportionately higher total daily dose was found among cervicalgia patients. The findings indicate that the responsiveness to an intrathecal narcotic during a trial, along with the diagnosis at the time of implantation, and the patient's age and gender can shed light on the long-term utilization of intrathecal analgesics in chronic non-cancer patients. This information may be used to better select patients and design trials that more closely reflect long-term drug utilization.

Neurologic complications including paralysis after a medication error involving implanted intrathecal catheters

PURPOSE

Long-term continuous intrathecal infusion of medications for chronic medical problems is common. We investigated the cause of a cluster of severe neurologic complications in patients with intrathecal catheters.

METHODS

We performed an epidemiologic cohort study of patients who had intrathecal catheters in place in one neurosurgical practice, to assess the presence of new neurologic complications and associated risk factors.

RESULTS

The practice included 61 patients who received pain medication through implanted intrathecal catheter pumps, 19 of whom were treated with morphine, either alone or in combination with other medications. None of the 42 patients whose drug regimen did not include morphine developed a complication, whereas 8 of 13 patients who received morphine in refills of their pumps during one 4-week period experienced neurologic complications. Three persons underwent laminectomy for sterile abscesses and were left with new paralysis or leg weakness. Testing of two stock bottles from the involved pharmacy, both labeled as containing pure morphine, revealed the presence of methadone in addition to morphine. One of these bottles also contained trace ethanol. A sample of medication aspirated from the pump of a patient prescribed morphine from the same pharmacy was also found to have contained methadone and methanol.

CONCLUSIONS

A variety of severe neurologic complications was associated with inadvertent administration of methadone, and perhaps other unintended substances, by means of implanted intrathecal catheters to a group of patients. Medical errors in an outpatient pharmacy led to this outbreak.

Inflammatory mass lesions associated with intrathecal drug infusion catheters: report and observations on 41 patients

OBJECTIVE

Several reports have described inflammatory mass lesions at the tip of intraspinal drug administration catheters. We evaluated the number of patients reported with this condition and whether data support hypotheses that have been put forth regarding the cause of these lesions.

METHODS

Information that was reported in the medical literature, and by Medtronic, Inc., to the United States Food and Drug Administration as of November 30, 2000, was reviewed.

RESULTS

Forty-one cases were identified, including 16 from the literature and 25 that were not published previously in the literature. Because of voluntary reporting and other methodological limitations, the actual number of cases must be higher than reported. All of the patients had chronic pain. The mean duration of therapy was 24.5 months. Most masses were located in the thoracic region. Intrathecal drugs included morphine or hydromorphone, either alone or mixed with other drugs, in 39 of 41 cases. No masses were reported in patients who received baclofen as the only intrathecal medication. Thirty patients underwent surgery to relieve spinal cord or cauda equina compression. Eleven patients were nonambulatory at last follow-up, and one died of a pulmonary embolus. Surgical specimens revealed noninfectious chronic inflammation, granuloma formation, and fibrosis or necrosis.

DISCUSSION

The most plausible hypothesis with regard to the cause of intrathecal catheter tip mass lesions implicates the administration of relatively high-concentration or high-dose opiate drugs or the use of drugs and admixtures that are not labeled for intrathecal use.

CONCLUSION

Patients who require high-dose intraspinal opioid therapy and those who receive drugs or admixtures that are not approved for intrathecal use should be monitored closely for signs of an extra-axial mass or catheter malfunction. Prompt diagnosis and treatment may preserve neurological function.

A prospective study of catheter-related complications of intrathecal drug delivery systems

Intrathecal drug administration via implanted pump is an effective treatment for intractable pain and spasticity but can be compromised by catheter-related complications. To determine the etiology of catheter-related complications, we have conducted a multicenter, prospective study of the long-term performance of a one-piece catheter system. Data pertaining to catheter-related complications were collected at implant and at specified times during the follow-up period. Catheter implantation characteristics that might affect complications were assessed. Two hundred nine patients were studied at 22 participating centers, with 1764 cumulative patient-months of catheter experience. Forty-nine catheter system complications occurred in 37 patients (7 complications related to the catheter itself, and 42 complications related to the implantation procedure). The 9-month complication-free "survival" rate was 78.9% overall (95.5% for the catheter itself). No specific catheter implantation characteristics were associated with the occurrence of complications. These data indicate that the incidence of complications for a one-piece catheter system is similar to that of commercially available two-piece systems, and highlight the need for careful surgical technique during implantation.

Stability of meperidine in an implantable infusion pump using capillary gas chromatography-mass spectrometry and a deuterated internal standard

A capillary gas chromatographic-mass spectrometric (GC MS) method is described for the analysis of meperidine using 3,3,5,5-[2H4]-meperidine as an internal standard. Chromatography was performed on a (5% phenyl) methylpolysiloxane column (30 m x 0.32 mm I.D., 0.25 microm film thickness) operated at 195 degrees C; helium carrier gas-50 cm/s(-1), tR = 2.3 min. Ionization was by electron impact (EI) and detection by selected ion monitoring of the molecular ions. The method provided high response linearity (mean r = 0.9982) and precision (< 6.5% C.V.). Application of this method to a pilot study of aqueous meperidine x HCl (10 mg/ml(-1)) stability in a surgically implantable infusion pump at 37 degrees C for 90 days revealed no demonstrable drug degradation.

Spinal cord compression by catheter granulomas in high-dose intrathecal morphine therapy: case report

OBJECTIVE AND IMPORTANCE

The use of chronic intrathecal morphine for the treatment of intractable, nonmalignant pain is becoming more prevalent. A rare but devastating complication of this therapy is the development of spinal cord compression secondary to the formation of intrathecal granulomas.

CLINICAL PRESENTATION

We report three cases of intrathecal granuloma formation in the thoracic subarachnoid space, associated with intrathecal morphine pumps. These three patients were receiving high doses of morphine to control their pain (25 mg/d, 28 mg/d, and 45 mg/d, respectively) when they presented with signs and symptoms of thoracic spinal cord compression. Myelography and postmyelographic computed tomography of the spine revealed masses causing spinal cord compression.

INTERVENTION

Two patients underwent thoracic laminectomies for resection of these masses, and the other patient had the intrathecal catheter removed. A pathological examination revealed sterile granulomas in the resected masses.

CONCLUSION

Intrathecal granulomas are likely to occur with increasing frequency as the use of chronic intrathecal morphine delivery increases in patients with nonmalignant pain. The cause of intrathecal granulomas is unknown, although it is likely that morphine plays a major role in their formation. We think that those patients receiving high doses of morphine are at greater risk for developing this complication.