Search

Introduction: Precise localization of the center of the reservoir access port (RAP) of intrathecal pump is a crucial step to ensure a safe refill procedure. In difficult refill cases, ultrasound guidance has been reported useful. Being more expensive and time-consuming, the purpose of the study was therefore to identify situations in which sonographic localization is more accurate than the template method, in order to restrict its use to these defined conditions., Materials and Methods: The RAP was localized using the template provided by the manufacturer and by ultrasound guidance. The distance between the two points was measured. A distance superior to 3.5 mm, corresponding to the radius of the silicone septum of the RAP, was considered a clinically significant deviation., Results: During the study period, 22 patients underwent a total of 81 refill procedures. No significant correlation was found between the distance between the two points and age, height, weight, body mass index (BMI) or abdominal perimeter. The correlation was significant between distance and pump's depth. According to the ROC curve, the sensitivity of ultrasound identification of the RAP was 69.2% and the specificity 83.3% when the pump was implanted at a depth of 10 mm., Discussion: Our results are comparable to these published in the literature, pointing the usefulness of ultrasound for refill of deeply implanted pumps. Our study provides an additional element by specifying the depth from which the ultrasound seems to be superior to template., Conclusion: Poor accuracy in RAP identification of intrathecal pump can lead to life-threatening complications. The results of our study suggest that the localization of recessed-RAP can be improved by ultrasound in cases of pump implanted deeper than 10 mm. For more superficially implanted devices, the template method seems to be as accurate as ultrasound., (© 2019 International Neuromodulation Society.)

Objective: Intrathecal drug delivery (ITDD) is commonly used for intractable pain management. A paucity of good-quality studies in chronic noncancer patients and concerns over increased dosages have focused interest on different modes of administration. The aim of this international multicenter randomized double-blind crossover trial was to compare the efficacy of the same daily dose of drugs administered by intermittent boluses vs simple continuous infusion., Methods: Eligible patients implanted with a programmable ITDD device were randomized to receive two weeks of either intermittent boluses or a simple continuous flow in period 1, followed by a crossover to the alternative mode of administration. The primary outcome measure was the Patients' Global Impression of Change (PGIC) scale., Results: The mean proportion of positive responders (at least "minimally improved") was 38.4% in the continuous condition vs 37.3% in the bolus (difference in proportions = 1.1%, 95% confidence interval [CI] = -21.8-24.0%, P  = 0.93). The mean PGIC in the continuous condition was 3.8 vs 3.9 in the bolus (mean difference = -0.1, -0.6-0.4, P  = 0.72). Exploratory analyses revealed a tendency for the mean proportion of positive responders to be higher at low vs high flow rates for both bolus and continuous administrations. Two patients were withdrawn from the study due to adverse events during the bolus phase, both with symptoms of increased pain, and one patient with additional symptoms of numbness and urinary retention., Conclusion: The mean PGIC and proportion of positive responders was not substantially different after intermittent bolus vs continuous administration., (© 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com)

Objectives: This study evaluated efficacy and safety of bolus doses of ziconotide (Prialt®, Eisai Limited, Hertfordshire, UK) to assess the option of continuous administration of this drug via an implanted intrathecal drug delivery system., Materials and Methods: Twenty adults with severe chronic pain who were under consideration for intrathecal (IT) therapy were enrolled in this open label, nonrandomized, pilot study. Informed consent was obtained. Demographics, medical/pain history, pain scores, and concomitant medications were recorded. A physical examination was performed. Creatine kinase was measured. Initial visual analog scale (VAS), blood pressure, heart rate, and respiratory rate were recorded. All patients received an initial bolus dose of 2.5 mcg ziconotide; the dose in the subsequent visits was modified according to response. Subsequent doses were 2.5 mcg, 1.2 mcg, or 3.75 mcg as per protocol. A good response (≥30% reduction in baseline pain VAS) with no side-effects on two occasions was considered a successful trial. Data were analyzed using a generalized estimating equations model, with pain VAS as the outcome and time (seven time points; preinjection and one to six hours postinjection) as the predictor., Results: Generalized estimating equations analysis of summary measures showed a mean reduction of pain VAS of approximately 25% at the group level; of 11 responders, seven underwent pump implantation procedure, two withdrew because of adverse effects, one refused an implant, and one could not have an implant (lack of funding from the Primary Care Trust)., Conclusions: Our data demonstrated that mean VAS was reduced by approximately 25% at the group level after IT ziconotide bolus. Treatment efficacy did not vary with sex, center, age, or pain etiology. Ziconotide bolus was generally well tolerated. Larger studies are needed to determine if bolus dosing with ziconotide is a good predictor of response to continuous IT ziconotide via an intrathecal drug delivery system., (© 2012 International Neuromodulation Society.)

Introduction: Intrathecal (IT) pump failures usually result in decreased drug administration and symptom reoccurrence with or without withdrawal syndrome. We report a case of a leaking silicone septum associated to a systemic drug overdose., Case Report: An 84-year-old patient treated with IT clonidine for chronic back pain presented with a state of confusion, visual hallucinations, and hypertension two hours after an unremarkable pump (SynchroMed EL, Medtronic, Minneapolis, MN, USA) refill. The reservoir was emptied and 14 mL (8.4 mg of clonidine) was found to be missing (difference between retrieved and expected volumes). The pump was refilled and a check on the next day showed again a loss of 3.5 mL. A malfunction was suspected and the pump was replaced (SynchroMed II, Medtronic). The inspection of the external surface of the pump revealed severe damage to the silicone septum with multiple gouges due to needle scarring. A fluid leak also was clearly seen through the septum., Discussion: The signs and symptoms presented by this patient are consistent with clonidine overdose that resulted from a combination of a possible accidental pocket fill and a definite septum leak into the subcutaneous tissue. The damage to the silicone could be due to the loss of the nontraumatic properties of the Huber needles that are rubbed against the metallic case in attempting to locate the injection port during refill procedures., Conclusion: This observation is the first description of a silicone septum damage contributing to a pump dysfunction and drug overdose despite the use of appropriate needles for refilling., (© 2012 International Neuromodulation Society.)

Background:   Complications associated with intrathecal pumps may be linked to the surgical procedure, the implanted device, or the medication itself., Case Reports:   Three patients treated chronically with intrathecal clonidine presented with clonidine overdose due to inadvertent extravasation during the refilling procedure. All patients experienced loss of consciousness and severe systemic hypertension that required aggressive parenteral treatment., Discussion:   Clonidine is an alpha-2 agonist with a nearly 100% bioavailability after oral or rectal administration. With high plasma concentration secondary to massive systemic overdose, the specificity for the alpha-2 receptor is lost and an alpha-1 agonist activity predominates and causes marked hypertension. Management of clonidine overdose consists of supportive therapy guided by signs and symptoms., Conclusion:   Inadvertent injection into the subcutaneous pocket rather than the reservoir is rare but very dangerous as the drug cannot be retrieved and massive doses are involved. Signs and symptoms of systemic overdose with drugs commonly used in implanted drugs delivery system should be well known to ensure early diagnosis and treatment., (© 2011 International Neuromodulation Society.)