Intrathecal Morphine Therapy-Related Granulomas: Faster to Grow than Thought

Narrative review of intrathecal drug delivery (IDD): indications, devices and potential complications

The management of chronic refractory pain (non-neoplastic and cancer-related pain) remains a therapeutic challenge. The continuous intrathecal (IT) administration of drugs may play an important role in the possible management options. Intrathecal drug delivery devices (IDDDs) may be effective for patients with refractory chronic pain. Therefore, they may be adopted for non-oncologic pain in patients with compression fractures, spondylolisthesis, spondylosis, back surgery failure syndrome and spinal stenosis. Oncologic patients can benefit from these treatments in a variable way according to tumor characteristics, prognosis, periprocedural imaging and risk of disease progression. In this review, we describe the most commonly used drugs (opioids and non-opioids), their pharmacokinetic and pharmacodynamic features and indications of use. The most used drugs are morphine, hydromorphone, fentanyl, methadone, bupivacaine, clonidine, and ketamine. Patient evaluation before the device implantation should be based on clinical examination, medical records assessment and psychometric evaluation. The infusion pumps available on the market are both non-programmable (with continuous IT deliver of drugs) and programmable (with variable deliver of drugs according to their flow rate). Moreover, we describe the procedure of implantation and the potential complications of IT drug delivery (such as bleeding, infection, loss of cerebrospinal fluid, wound seroma, loss of catheter pump propellant).

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.

Current perspectives on intrathecal drug delivery

Advances in intrathecal analgesia and intrathecal drug delivery systems have allowed for a range of medications to be used in the control of pain and spasticity. This technique allows for reduced medication doses that can decrease the side effects typically associated with oral or parenteral drug delivery. Recent expert panel consensus guidelines have provided care paths in the treatment of nociceptive, neuropathic, and mixed pain syndromes. While the data for pain relief, adverse effect reduction, and cost-effectiveness with cancer pain control are compelling, the evidence is less clear for noncancer pain, other than spasticity. Physicians should be aware of mechanical, pharmacological, surgical, and patient-specific complications, including possible granuloma formation. Newer intrathecal drug delivery systems may allow for better safety and quality of life outcomes.

Polyanalgesic Consensus Conference 2012: recommendations for the management of pain by intrathecal (intraspinal) drug delivery: report of an interdisciplinary expert panel

INTRODUCTION

The use of intrathecal (IT) infusion of analgesic medications to treat patients with chronic refractory pain has increased since its inception in the 1980s, and the need for clinical research in IT therapy is ongoing. The Polyanalgesic Consensus Conference (PACC) panel of experts convened in 2000, 2003, and 2007 to make recommendations on the rational use of IT analgesics based on preclinical and clinical literature and clinical experiences.

METHODS

The PACC panel convened again in 2011 to update the standard of care for IT therapies to reflect current knowledge gleaned from literature and clinical experience. A thorough literature search was performed, and information from this search was provided to panel members. Analysis of published literature was coupled with the clinical experience of panel members to form recommendations regarding the use of IT analgesics to treat chronic pain.

RESULTS

After a review of literature published from 2007 to 2011 and discussions of clinical experience, the panel created updated algorithms for the rational use of IT medications for the treatment of neuropathic pain and nociceptive pain.

CONCLUSIONS

The advent of new algorithmic tracks for neuropathic and nociceptive pain is an important step in improving patient care. The panel encourages continued research and development, including the development of new drugs, devices, and safety recommendations to improve the care of patients with chronic pain.

Can an intrathecal, catheter-tip-associated inflammatory mass reoccur?

OBJECTIVES

Intrathecal granuloma associated to the tip of catheters implanted in patients receiving long-term spinal infusion to alleviate chronic pain is a rare but potentially catastrophic complication. Its formation seems to be related to the intrathecal administration of opioid drugs, although not all opioids induce granuloma formation with the same frequency.

METHODS

In this clinical report, we describe an intrathecal granuloma that reoccur twice in the same patient after its surgical removal.

RESULTS AND DISCUSSION

This case report highlights the incomplete knowledge about the mechanism of granuloma formation and discuss the alternatives in the management of catheter-tip granulomas. This is the first case report of a patient in whom an intrathecal granuloma reoccurred twice after initial surgical removal. We also present and discuss a potential management strategy to avoid further surgery and resume intrathecal therapy early.

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.