A prospective analysis of intrathecal granuloma in chronic pain patients: a review of the literature and report of a surveillance study.

BACKGROUND

Over the past decade granulomas have been noted to occur at or near the tip of intrathecal catheters used for spinal infusions. The majority of cases involved morphine infusions, although other drugs have been implicated. Granulomas may be asymptomatic or cause significant neurological deficits.

METHODS

Consecutive patients with intrathecal infusions were examined for the presence of intrathecal granulomas. MRI or CT was used to make the diagnosis.

RESULTS

A total of 208 patients underwent imaging over a period of 34 weeks. Six patients (3%) were found to have a significant lesion. Five of the six patients were asymptomatic and one patient complained of radicular pain in the distribution of the catheter tip. The average catheter infusion time for patients with granulomas was 27 months, not significantly different from patients without granulomas. No specific characteristics, such as drugs or concentrations were identified. All six patients had percutaneous catheter revisions without complication.

CONCLUSION

Intrathecal granulomas were identified in 3% of patients imaged in this series. Eighty percent of the patients were asymptomatic. MRI imaging remains the diagnostic method of choice for most patients, and can be done safely when scans are taken at the level of the catheter tip. Given the low incidence of granulomas with intrathecal catheters, routine imaging to identify granulomas is not warranted.