Implantable Intrathecal Pump Research Articles

Management of chronic malignant pain – an updated review

Cancer Pain is a multidimensional pain experience which involves diverse neurophysiological changes and is associated with significant cognitive, emotional and sociocultural problems. Globally, the incidence is very high and usually it is undertreated Lack of knowledge about managing malignant pain is an important cause of undertreatment. All types of pain are possible with malignancies. Assessment of pain characteristics is vital for proper management. The WHO step ladder pattern is the cornerstone of management. There are different pharmacological and nonpharmacological methods. Morphine is the choice opioid being administered by various routes. All drugs should be used as round the clock regimen. Opioid switch is opted to tackle tolerance. Nerve blockade especially with alcohol are still being used today. Newer treatment modalities like implantable intrathecal pumps, dorsal column stimulation are in the pipeline for future. A passionate counselling may frequently release knotted conundrum of difficult analgesic strategies.

Implantable Intrathecal Drug Delivery Pump in Complex Regional Pain Syndrome Patient -A case report-

Implantable intrathecal pump is one of the therapeutic options for intractable pain. A 24-year-old male with complex regional pain syndrome was suffering from right lower extremity pain. He had all modalities of treatment including spinal cord stimulator. However, his pain had been worse in the past 6 months. His visual analogue pain scale (VAS) was 8−10 and he could not sit or walk. Only opioid was thought to be effective. Then, intrathecal pump was considered. We estimated the minimal effective dose of spinal morphine before implantation. 0.3 mg of morphine was injected intrathecally as a starting dose. Dosage had been increased up to 0.8 mg in 10 days. His VAS score decreased from 8 to 5. He could sleep without pain and walk with crutch. Therefore, intrathecal pump was inserted. He could tolerate to pain. This case suggests that intrathecal morphine delivery can provide effective treatment for intractable non-malignant pain.

Implantable Intrathecal Pumps for the Treatment of Noncancer Chronic Pain in Elderly Population: Drug Dose and Clinical Efficacy

Objective. This study aims to assess long-term follow-up of efficacy and quality of life for 34 geriatric patients (10 men, 24 women, mean age 72.3±11.6years) with intrathecal (IT) drug delivery systems (IDDS), implanted between 1994 and 2002, for the treatment of severe noncancer chronic pain. Methods. Patients equal to or older than 64years, who had no pain relief after administration of a placebo injection (subcutaneous saline), and who responded positively to an IT trial (morphine and bupivacaine at low doses) with pain relief greater 70% without intolerable adverse effects were included into our study. Clinical assessment forms and questionnaires assessing pain intensity, adverse events, complications, concommitent use of analgesics, and doses of IT drugs administered were filled out by our patients prior to and after IT drug delivery implantation. Results. Pain intensity was substantially reduced (60%) at three-month follow-up after commencing IT therapy and was consistently reduced at 48-month follow-up. The mean visual analog scale (VAS) value decreased from 8.09 (±1.25) before implantation to 1.68 (±0.63) after implantation at 48-month follow-up. This benefit, at 48months, was achieved using mean low doses of IT morphine and bupivacaine, 1.03±0.61mg and 1.15±0.58mg, respectively. Only two out of 34 patients (5.9%) had complications related to the implantation procedure, itself. Side-effects of therapy were reported by 50% of the patients, the most frequent being constipation (34.4%), drowsiness (21.9%), nausea (21.9%), and urinary retention (18.8%). No side-effects of therapy resulted in removal of the IDDS. Conclusion. The use of IT drug delivery through IDDS for the treatment of non-cancer- and cancer-related pain in geriatric patients is successful.

Chemical Stability of Admixtures Combining Ziconotide With Baclofen During Simulated Intrathecal Administration

Objective. To determine the stability of admixtures combining ziconotide with commercially formulated or powdered baclofen during simulated intrathecal infusion under laboratory conditions at 37°. Materials and Methods. Admixtures of ziconotide (25µg/mL) with commercially formulated (1.5mg/mL) or powdered (2.0mg/mL) baclofen were stored in implantable intrathecal pumps at 37°. Drug concentrations were determined with high-performance liquid chromatography, and the length of time that the concentrations of both drugs remained≥90% and≥80% of initial (ie, the 90% and 80% stability, respectively) was estimated based on lower 95% confidence bounds obtained via linear regression. Results. Baclofen was stable in both admixtures. In the commercially formulated baclofen admixture, the mean ziconotide concentration declined to 82.2% of initial in 30days; the estimates for 90% and 80% stability were 12 and 29days, respectively. In the powdered baclofen admixture, the mean ziconotide concentration declined to 87.4% of initial in 30days; the estimates for 90% and 80% stability were 20 and 41days, respectively. Conclusion. Ziconotide-baclofen admixtures were more stable when prepared using powdered baclofen rather than a commercial baclofen formulation.

Stability of clonidine in clonidine-hydromorphone mixture from implanted intrathecal infusion pumps in chronic pain patients

Clonidine is frequently added to opioids in implantable intrathecal pumps for the management of chronic pain. In such devices, a small non-retrievable volume is always present in the reservoir, and its effect on drug stability is unknown. Furthermore, stability of clonidine, when mixed with hydromorphone, has not been previously determined. This study examined the stability of clonidine when co-administered with hydromorphone in implanted intrathecal pumps. Samples of hydromorphone-clonidine before pump refill and from residual solution at subsequent refill were obtained from chronic pain patients. Clonidine concentration was measured using HPLC. Twenty paired samples from 3 patients were analyzed. All 3 patients had a SynchroMed pump implanted for 3–5 years. We found no loss in clonidine concentration during the time between refills (35 ± 13 days), and no correlation between clonidine concentration and time interval between refills. In conclusion, clonidine, mixed with hydromorphone, is stable when delivered by implantable intrathecal pump for long-term use.

Other: Long term stability of clonidine in clonidine-hydromorphone mixture in implanted intrathecal infusion pumps

Clonidine is frequently added to opioid in implantable intrathecal infusion pumps for the management of chronic pain, especially in those with chronic neuropathic pain. Previous studies on the clonidine stability conducted in vitro with the solution inside the infusion pump at body temperature suggested that clonidine was stable in mixture with morphine under this condition. When applying this data to clinical settings, two concerns remain. There is a non-retrievable volume of 2.4 ml in the reservoir, which has potential for degradation over months or years. Moreover, the stability of clonidine when mixed with other opioids such as hydromorphone is unknown. The aim of the present study was to examine the long-term stability of clonidine when administered with hydromorphone in implanted intrathecal pumps to non-cancer, chronic pain patients. Following REB approval and informed consent, samples were taken from hydromorphone-clonidine mixtures collected before pump refill and from the residual solution in the subsequent refill. The clonidine concentration used were 150mcg/ml in all patients. Following collection, the samples were frozen and transferred to the laboratory for analysis of clonidine concentration by High Performance Liquid Chromatography. Data are presented as mean+SD and compared with paired Student t-test. Twenty paired samples from 3 patients with refilling interval of 35+13days were analyzed. All 3 patients had SyncroMed® implanted for a duration ranging from 3-5 years. There was no statistical difference in clonidine concentration before and after refill (145.6+5.6 vs 145.6+7.1 mcg/mL respectively). Based on our data, only 5 paired samples were required to show a difference of 15% with type I and II error of 0.05 and 0.2. Clonidine, when mixed with hydromorphone, is stable when delivered by implantable intrathecal pump for long term use.