Applying a Part of the Daily Dose as Boli May Improve Intrathecal Opioid Therapy in Patients With Chronic Pain.

OBJECTIVES: The speed of intrathecal drug administration (slow continuous infusion vs. rapid bolus application) might influence the efficacy of therapy despite the equal daily dose in both administration patterns. We tested this hypothesis in a small prospective single-centre pilot study in a population of chronic pain patients with intrathecal opioid therapy. METHODS: Ten patients receiving intrathecal opioids for chronic pain assessed their pain four times daily on a numeric rating scale (NRS), more than the time course of six weeks divided into three blocks of two weeks each: Baseline evaluation (intrathecal pumps with previously established continuous infusion settings), followed by two blinded trial blocks of continuous (same pump parameters as during evaluation) and bolus (40% of daily dose split into four equal boli applied every six hours, with the remaining 60% as background continuous infusion) regimes. Patients were randomized in a crossover fashion. RESULTS: 6/10 patients reported significantly lower NRS-scores during bolus as compared to continuous trial blocks while only one patient showed the opposite effect. Overall, bolus trial blocks were associated with a small but significant reduction of NRS-scores (mean -0.56; p < 0.0001). Side-effects related to bolus infusions were not reported. CONCLUSIONS: Intermittent bolus administration may be helpful for increasing the efficacy of intrathecal opioid therapy of chronic pain.

Successful spinal cord stimulation for neuropathic below-level spinal cord injury pain following complete paraplegia: a case report.

INTRODUCTION: Neuropathic pain is common in patients with spinal cord injury (SCI) and often difficult to treat. We report a case where epidural spinal cord stimulation (SCS) below the level of injury has been successfully applied in a patient with a complete spinal cord lesion. CASE PRESENTATION: A 53-year-old female presented with neuropathic below-level SCI pain of both lower legs and feet due to complete SCI below T5. Time and pain duration since injury was 2 years. Pain intensity was reported on numeric rating scale with an average of 7/10 (0 meaning no pain, 10 meaning the worst imaginable pain), but also with about 8-10 pain attacks during the day with an intensity of 9/10, which lasted between some minutes and half an hour. SCS was applied below the level of injury at-level T11-L1. After a successful 2 weeks testing period the pulse generator has been implanted permanently with a burst-stimulation pattern. The average pain was reduced to a bearable intensity of 4/10, in addition attacks could be reduced both in frequency and in intensity. This effects lasted for at least three months of follow-up. DISCUSSION: Even in case of complete SCI, SCS might be effective. Mechanisms of pain relief remain unclear. A modulation of suggested residual spinothalamic tract function may play a role. Further investigation has to be carried out to support this theory.

Catheter-tip Granulomas Associated with Intrathecal Drug Delivery--A Two-Center Experience Identifying 13 Cases.

BACKGROUND: Intrathecal (IT) drug therapy with implanted pumps is an effective treatment modality for chronic pain and/or spasticity, especially after non-invasive treatment has failed. Long-term use of intrathecal opioids may cause formation of inflammatory masses at the tip of intrathecal catheters, possibly leading to neurological deficits and/or catheter revision. OBJECTIVE: We aimed to identify risk factors for catheter-tip granuloma (CG) formation. STUDY DESIGN: Retrospective study. SETTING: Tertiary Spine Centers in Germany and Switzerland. METHODS: We retrospectively reviewed data at 2 Swiss centers (Kantonsspital St. Gallen, Swiss Paraplegic Centre Nottwil) between 01/1994 and 10/2013. Collected data were age at operation, gender, smoking status, previous spinal operations, spinal level of catheter-tip, clinical symptoms, catheter testing with contrast agent, applied drugs, drug concentration, as well as cumulative daily drug dosages. RESULTS: Thirteen patients with a mean age of 52.6 years and CG formation after a mean of 6.9 years of follow-up were identified and compared to 54 patients of similar age and length of follow-up (48.6 years, P = 0.535; follow-up 5.3 years, P = 0.236) without CG. In the analysis of risk factors, catheter ending in the middle thoracic spine (Th4-8; 38.5 vs. 6.5%; P = 0.010), previous spinal surgery (75 vs. 41%; P = 0.051), and chronic pain as an underlying primary symptom for IT drug therapy (100 vs. 56%, P = 0.003) were associated with CG formation. IT drug therapy for spasticity appeared to be much less associated with CG formation (0 vs. 44%, P = .0003). As the symptomatology is closely related to the medical treatment applied, patients with CG were more likely to be treated with IT morphine (77 vs. 20%; P < 0.001), and as tendency with IT clonidine (54 vs. 26%; P = 0.092) and IT bupivacaine (46 vs. 20%; P = 0.077). Average in-pump morphine concentration (30.3 vs. 19.5 mg/mL; P = 0.05) as well as average daily dose of morphine (12.5 vs. 6.2 mg/d; P = 0.037) were significantly higher in the CG group. Smoking could not be identified as risk factor for CG formation. LIMITATIONS: Limitations include the retrospective approach, the limited group size of granuloma patients, as well as missing data in the investigated patient groups. CONCLUSION: Our patient cohort with CG differed in some features, of which some like catheter localization, choice, dosage, and the concentration of drugs are potentially modifiable. These results could contribute to the prevention of CG in the future.