Intrathecal granuloma and intramedullary abscess associated with an intrathecal morphine pump.

Objective and Importance.  Several previous reports have documented cord compression resulting from the formation of an intrathecal inflammatory mass in patients using intrathecal drug delivery systems. We present the first reported case of an intramedullary abscess and intrathecal inflammatory mass associated with an intrathecal drug delivery system. Clinical Presentation.  A 47-year-old man was transferred to our institution from an outside hospital with a 3-week history of the inability to ambulate or move his legs. His medical history included multiple failed back surgeries for back pain that had been effectively managed after the implantation of an intrathecal drug delivery system eight years prior. Upon presentation to us, his examination showed no movement in his lower extremities with pinprick-preserved sensation in his toes. Imaging showed an intrathecal mass at the catheter tip, at spinal level T10 and T11. Contrast-enhanced imaging indicated an intramedullary abscess at T11 and T12 level. Intervention.  The patient underwent T10-L1 laminectomies with complete resection of the inflammatory mass, catheter tip, and explantation of the intrathecal drug delivery pump. A midline myelotomy also was performed to aspirate the abscess and the cavity was profusely irrigated. Pathology studies demonstrated that the inflammatory mass contained chronic inflammatory markers and necrotic tissue. The abscess was linked to infection with Streptococcus anginosus. Conclusion.  Generally, inflammatory masses forming along the catheter tip are not associated with infections. We report the first case of an intramedullary abscess associated with an intrathecal drug delivery pump.