The Polyanalgesic Consensus Conference (PACC)®: Intrathecal Drug Delivery Guidance on Safety and Therapy Optimization When Treating Chronic Noncancer Pain.

INTRODUCTION: The International Neuromodulation Society convened a multispecialty group of physicians and scientists based on expertise with international representation to establish evidence-based guidance on intrathecal drug delivery in treating chronic pain. This Polyanalgesic Consensus Conference (PACC)® project, created more than two decades ago, intends to provide evidence-based guidance for important safety and efficacy issues surrounding intrathecal drug delivery and its impact on the practice of neuromodulation. MATERIALS AND METHODS: Authors were chosen on the basis of their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from 2017 (when PACC® last published guidelines) to the present. Identified studies were graded using the United States Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on the strength of evidence or consensus when evidence is scant. RESULTS: The PACC® examined the published literature and established evidence- and consensus-based recommendations to guide best practices. Additional guidance will occur as new evidence is developed in future iterations of this process. CONCLUSIONS: The PACC® recommends best practices regarding intrathecal drug delivery to improve safety and efficacy. The evidence- and consensus-based recommendations should be used as a guide to assist decision-making when clinically appropriate.

Risk Factors Associated with Postoperative Cerebrospinal Fluid Leaks After Intrathecal Drug Delivery System and an External Pump Implantation in Cancer Patients: A Retrospective Study.

INTRODUCTION: To determine risk factors associated with postoperative cerebrospinal fluid leaks (CSFLs) after intrathecal drug delivery system (IDDS) and external pump implantation. METHODS: The clinical data of 248 patients with advanced cancer who underwent IDDS implantation from January 2021 to December 2022 at the Department of Pain Medicine at the Hunan Cancer Hospital were retrospectively reviewed. Information regarding age, gender, height, weight, body mass index (BMI), tumour type, albumin levels, haemoglobin levels, history of diabetes and pre- and postoperative anti-tumour therapy was collected and analysed. RESULTS: Postoperative CSFLs occurred in 7 of 231 patients (3.30%). Statistical analysis indicated that gender, age, height, weight, BMI, tumour type, albumin levels, haemoglobin levels, history of diabetes, pre- and postoperative chemotherapy, pre- and postoperative radiotherapy, preoperative immunotherapy and postoperative targeted therapy were not independent factors for CSFLs. Preoperative targeted therapy [odds ratio (OR): 16.64; 95% confidence interval (CI): 1.42, 195.56; P = 0.01] and postoperative immunotherapy (OR: 13.38; 95% CI: 1.60, 111.65; P = 0.017) were factors associated with an increased postoperative CSFL rate. Of the two locations where CSFLs can occur, the back (puncture site of catheter, n = 4) and the hypochondriac region (location of infusion port implanted, n = 3), back CSFLs occurred earlier than in the hypochondriac region (18.25 ± 6.45 vs 115 ± 62.02 days, P = 0.032). CONCLUSION: Based on the data from our study, the timing of preoperative targeted therapy and postoperative immunotherapy should be considered to prevent the occurrence of CSFLs in cancer pain patients who have an IDDS and external pump.

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OBJECTIVES: The distribution characteristics of intrathecal drugs and the limitation of current catheterization techniques make traditional intrathecal analgesic treatment nearly useless for refractory craniofacial pain, such as trigemina neuralgia. This technical guideline aims to promote the widespread and standardize the application of intra-prepontine cisternal drug delivery via spinal puncture and catheterization. METHODS: A modified Delphi approach was used to work for this guideline. On the issues related to the intra-prepontine cisternal targeted drug delivery technique, the working group consulted 10 experts from the field with 3 rounds of email feedback and 3 rounds of conference discussion. RESULTS: For the efficacy and safety of the intra-prepontine cisternal targeted drug delivery technique, a consensus was formed on 7 topics (with an agreement rate of more than 80%), including the principles of the technique, indications and contraindications, patient preparation, surgical specifications for intra-prepontine cisternal catheter placement, analgesic dosage coordination, analgesic management, and prevention and treatment of complications. CONCLUSIONS: Utilizing the intra-prepontine cisternal drug infusion system to manage refractory craniofacial pain could provide advantages in terms of minimally invasive, secure, and effective treatment. This application can not only alleviate the suffering of individuals experiencing the prolonged pain but also support the maintenance of quality of life and dignity in their final moments, justifiing its widespread dissemination and standardized adoption in domestic and international professional fields.

Implanted intrathecal drug delivery systems may be associated with improved survival in patients with cancer.

Background: Intrathecal Drug Delivery Systems (IDDS) are underused in the management of cancer-related pain despite evidence of both efficacy and survival benefit. There is currently limited evidence to indicate which patients might benefit most from IDDS. Aim: The aim of the study was to describe the baseline characteristics and survival outcomes of patients who accepted IDDS, patients who declined IDDS and patients who wished to go ahead with IDDS but whose condition deteriorated before they could do so. Design/participants: The survival data for 75 consecutive patients who had been offered intrathecal drug delivery were examined as part of a retrospective cohort study. Survival data was compared between three groups: those who accepted intrathecal drug delivery and went on to receive it (n = 41), those who accepted it but whose condition deteriorated before it commenced (n = 17) and those who declined this treatment modality (n = 17). Results: Patients who received IDDS survived significantly longer after assessment compared to those who declined IDDS (hazard ratio (HR) for the IDDS group relative to the declined group 0.29 (95% CI 0.16 to 0.53), and 0.23 (95% CI 0.12 to 0.44) after adjustment for gender and baseline functional status. In patients who accepted IDDS but who were unable to commence treatment, survival after assessment was not significantly different from those who declined the IDDS (HR for the deteriorated group relative to the declined group 1.28 (95% CI 0.65 to 2.53), and 0.80 (95% CI 0.65 to 2.53) after adjustment for gender and baseline functional status). Conclusion: In this retrospective analysis, an improvement in survival may be associated with patients who accept ongoing pain management with an implanted intrathecal drug delivery system compared to those patients who either declined intrathecal drug delivery or deteriorated before it could be commenced.

Position-Dependent Intrathecal Baclofen System Catheter Failure Resulting in Debilitating Spasticity: A Case Report.

An intrathecal baclofen pump (ITB) can provide significant relief from excessive spasticity and pain that is difficult to control. However, it is not without its drawbacks. We present a case of a young quadriplegic male who underwent ITB pump placement, suffering four years of transient episodes of severe spasticity with withdrawal symptoms. Multiple adjustments were made to his ITB pump dosing without relief. Extensive workup including interrogation of the pump, serial abdominal radiographs, and fluoroscopic catheter dye study revealed no abnormalities. Intraoperatively, it was discovered that the initial catheter anchoring occurred directly adjacent to the vertebrae, leading to a position-dependent catheter occlusion. He underwent the replacement of his ITB pump and catheter. During surgical revision, emphasis was placed on reducing the length of the catheter outside the spine, anchoring to the supraspinous fascia with avoidance of bony prominences or post-laminectomy sites. After surgery, the patient's spasticity improved, and at the eight-month follow-up, he had no complications, resulting in a mean baclofen dose of 300.2 µg/day. This report highlights the potential risk of life-threatening intrathecal baclofen withdrawal secondary to postural changes, providing technical considerations to prevent recurrences. It also raises awareness regarding patients who are more susceptible to transient catheter occlusion after a spinal cord injury.

Refinement of intrathecal catheter design to enhance neuraxial distribution.

BACKGROUND: Delivery of therapeutics via indwelling intrathecal catheters is highly efficacious for targeting of pain, spasticity, neuraxial cancer and neurodegenerative disorders. However, current catheter designs have some major limitations. Given limited CSF flow, fixed intrathecal volume and the large distance of the rostro-caudal spinal axis, current intrathecal delivery routes fail to achieve adequate drug distribution. Additionally open catheter systems are plagued with cellular ingrowth and debris accumulation if used intermittently. NEW METHOD: RESULTS/COMPARISON WITH EXISTING METHOD(S): High speed imaging showed micro-valve catheters greatly increase fluid exit velocities compared to typical open-ended catheters, which prevents pooling of injectate proximal to the opening. When implanted intrathecally in rats, small injection volumes (7.5 µL) of dye or AAV9-RFP, resulted in an even rostro-caudal distribution along the spinal axis and robust transfection of neurons from cervical to lumbar dorsal root ganglia. In contrast, such injections with an open-ended catheter resulted in localized distribution and transfection proximal to the delivery site. Our poly micro-valve catheter design resulted in equivalent transfection rates of cervical DRG neurons using 100x lower titer of AAV9-RFP. Unlike open port catheters, no debris accumulation was observed in the lumen of implanted catheters, showing potential for long-term intermittent use. CONCLUSIONS: This catheter platform, suitable for small animal models is easily scalable for human use and addresses many of the problems observed with common catheter systems.

Interpeduncular cistern intrathecal targeted drug delivery for intractable postherpetic neuralgia: A case report.

BACKGROUND: Intractable postherpetic neuralgia (PHN) can be difficult to manage even with aggressive multimodal therapies. Patients who experience uncontrolled refractory cranial PHN despite conservative treatment may benefit from an intrathecal drug delivery system (IDDS). For craniofacial neuropathic pain, the traditional approach has been to place the intrathecal catheter tip below the level of the cranial nerve root entry zones, which may lead to insufficient analgesia. CASE SUMMARY: We describe a 69-year-old man with a 1-year history of PHN after developing a vesicular rash in the ophthalmic division of cranial nerve V (trigeminal nerve) distribution. The pain was rated 7-8 at rest and 9-10 at breakthrough pain (BTP) on a numeric rating scale. Despite receiving aggressive multimodal therapies including large doses of oral analgesics (gabapentin 150 mg q12 h, oxycodone 5 mg/acetaminophen 325 mg q6 h, and lidocaine 5% patch 700 mg q12 h) and sphenopalatine ganglion block, there was no relief of pain. Subsequently, the patient elected to have an implantable IDDS with the catheter tip placed at the interpeduncular cistern. The frequency of BTP episodes decreased. The patient's continuous daily dose was adjusted to 0.032 mg/d after 3 mo of follow-up and stopped 5 mo later. He did not report pain or other discomfort at outpatient follow-up 6 mo and 1 year after stopping intracisternal hydromorphone. CONCLUSION: The use of interpeduncular cistern intrathecal infusion with low-dose hydromorphone by IDDS may be effective for severe craniofacial PHN.

Determination of spinal tracer dispersion after intrathecal injection in a deformable CNS model.

Background: Traditionally, there is a widely held belief that drug dispersion after intrathecal (IT) delivery is confined locally near the injection site. We posit that high-volume infusions can overcome this perceived limitation of IT administration. Methods: To test our hypothesis, subject-specific deformable phantom models of the human central nervous system were manufactured so that tracer infusion could be realistically replicated in vitro over the entire physiological range of pulsating cerebrospinal fluid (CSF) amplitudes and frequencies. The distribution of IT injected tracers was studied systematically with high-speed optical methods to determine its dependence on injection parameters (infusion volume, flow rate, and catheter configurations) and natural CSF oscillations in a deformable model of the central nervous system (CNS). Results: Optical imaging analysis of high-volume infusion experiments showed that tracers spread quickly throughout the spinal subarachnoid space, reaching the cervical region in less than 10 min. The experimentally observed biodispersion is much slower than suggested by the Taylor-Aris dispersion theory. Our experiments indicate that micro-mixing patterns induced by oscillatory CSF flow around microanatomical features such as nerve roots significantly accelerate solute transport. Strong micro-mixing effects due to anatomical features in the spinal subarachnoid space were found to be active in intrathecal drug administration but were not considered in prior dispersion theories. Their omission explains why prior models developed in the engineering community are poor predictors for IT delivery. Conclusion: Our experiments support the feasibility of targeting large sections of the neuroaxis or brain utilizing high-volume IT injection protocols. The experimental tracer dispersion profiles acquired with an anatomically accurate, deformable, and closed in vitro human CNS analog informed a new predictive model of tracer dispersion as a function of physiological CSF pulsations and adjustable infusion parameters. The ability to predict spatiotemporal dispersion patterns is an essential prerequisite for exploring new indications of IT drug delivery that targets specific regions in the CNS or the brain.

Does lumbar spinal decompression or fusion surgery influence outcome parameters in patients with intrathecal morphine treatment for persistent spinal pain syndrome type 2 (PSPS-T2).

OBJECTIVES: Intrathecal morphine pump (ITMP) infusion therapy is efficient in managing chronic pain refractory to standard treatment. This study evaluates pain relief and improvement of quality of life in chronic pain patients after intrathecal morphine pump implantation for treatment of persistent pain after lumbar spinal fusion surgery and lumbar spinal decompression alone. METHODS: Forty three chronic pain patients that received an ITMP at our department between 2009 and 2019 were retrospectively analyzed divided into 2 cohorts (lumbar spinal fusion surgery and lumbar spinal decompression alone). Pain intensity was evaluated using the numeric rating scale (NRS), quality of life was assessed by EQ-5D-3L, mental health was assessed by Beck Depression Inventory (BDI-V), and Pain Catastrophizing Scale (PCS). Morphine dosage was assessed over time. Data was collected preoperatively, 6 and 24 months postoperatively. Statistical analysis was performed using Friedman's analysis of variance to evaluate the development of NRS, PCS, BDI and EQ-5D-3L over time and Mann-Whitney-U-test for the differences between these parameters in the different cohorts. A two-sided p-value <0.05 was considered statistically significant. RESULTS: Median age was 64 years (IQR25-75 56-71 years). NRS, EQ-5D-3L, BDI-V, and PCS showed a significant overall improvement after 6 and 24 months compared to baseline data (p<0.001). No statistically significant differences between patients with lumbar spinal fusion surgery and lumbar spinal decompression alone were seen. Furthermore, no statistically significant differences for age and gender were seen. The initially administered median morphine dosage was significantly higher in the fusion group (3.0 mg/day; IQR25-75 1.5-4.2 mg/day) compared to the decompression-alone group (1.5 mg/day; IQR25-75 1.0-2.6 mg/day); (p=0.027). CONCLUSIONS: This retrospective study showed that ITMP have a major long-term impact on pain relief, improve the quality of life, psychological distress, as well as pain catastrophizing in patients with chronic pain following lumbar spinal surgery independent of the previous surgical procedure. After ITMP implantation initial median morphine dosage seems to be significantly higher after spinal fusion compared to decompressive surgery alone.

Managing intractable pain with neuraxial infusion at home.

A case study of a 9-year-old child with complex pain secondary to metastatic liver cancer, who eventually required intrathecal drug delivery (ITDD) of analgesia. Multi-modal symptom control strategies were deployed to achieve the child's and parental wishes for end-of-life care (EoLC) at home using ITDD. The following recommendations are made for nursing practice in paediatric palliative care (PPC); rigorous risk assessment, exemplary communication with the identification of a coordinating team, timely training needs assessment and the delivery of training from hospital based experts in ITDD practice, comprehensive symptom management plan and 24/7 access to specialist palliative care teams were essential for safe nursing practice. In this case, robust risk assessment and mitigations enabled challenges to be safely addressed with a successful outcome, extending the boundaries of PPC home care.

Risk factors for surgical site infection in advanced neuromodulation pain procedures: a retrospective study.

Aim: To assess the effects of diabetes mellitus (DM) and related variables on surgical site infection (SSI) risk in neuromodulation. Methods: This retrospective study followed patients who underwent neuromodulation procedures for at least 9 months to identify postoperative infections. Demographics, clinical characteristics and surgical outcomes were compared. Results: Of 195 cases included, 5 (2.6%) resulted in SSIs. Median HbA1c was significantly higher for the cases with SSIs (8.2 vs 5.6%; p = 0.0044). The rate of SSI was significantly higher among patients with DM (17.9 vs 0%; p = 0.0005), HbA1c≥7% (37.5 vs 0%; p = 0.0009), and perioperative glucose ≥200 mg/dl (40 vs 2.3%; p = 0.0101). Conclusion: DM, elevated HbA1c and perioperative hyperglycemia may all contribute to increased risk of SSIs with neuromodulation procedures.

Infections are feared complications of surgery. It is important to identify factors that increase the risk of infection to prevent these complications. This study looked at the effects of diabetes and high blood sugar on the risk of infection associated with pain procedures. The researchers followed patients who had these procedures and looked for any infections that occurred afterward. They found that patients with diabetes and high blood sugar levels before surgery were more likely to develop infections after these procedures. More research can help establish blood sugar targets so that physicians can better manage this risk for their patients.

Minimally invasive interventional therapy for pain.

Pain interventional therapy, known as the most promising medical technology in the 21st century, refers to clinical treatment technology based on neuroanatomy, neuroimaging, and nerve block technology to treat pain diseases. Compared with traditional destructive surgery, interventional pain therapy is considered a better and more economical choice of treatment. In recent years, a variety of minimally invasive pain interventional therapy techniques, such as neuroregulation, spinal cord electrical stimulation, intervertebral disc ablation, and intrasheath drug infusion systems, have provided effective solutions for the treatment of patients with post-herpetic neuralgia, complex regional pain syndrome, cervical/lumbar disc herniation, and refractory cancer pain.

Intrathecal Drug Delivery Systems for Cancer Pain Control: Insights on Current Contemporary Practices in the US.

OBJECTIVES: Among patients with cancer with moderate to severe, intractable pain, intrathecal drug delivery using an intrathecal drug delivery system (IDDS) offers effective pain control. In this study, we evaluate the trends of IDDS therapy among patients with cancer, associated comorbidities, complications, and outcomes, using a large representative US administrative inpatient data base. MATERIALS AND METHODS: The Nationwide Inpatient Sample (NIS) data base contains data from 48 states and the District of Columbia. The NIS was used to identify patients with cancer who underwent IDDS implantation between 2016 and 2019. Patients with cancer with intrathecal pumps for the treatment of chronic pain were identified using administrative codes. Baseline demographics, hospital characteristics, type of cancer associated with IDDS implantation, palliative care encounters, hospitalization costs, length of stay, and prevalence of bone pain were evaluated in the study. RESULTS: A total of 22,895 (0.32%) individuals with hospital admission for IDDS surgery were included for analysis among 7.06 million individuals with cancer in the final cohort. The IDDS cohort consisted of patients predominantly in the 65-to-79 years age group (40.49%), female sex (50.42%), and Caucasian ethnicity (75.82%). The top five cancers in patients receiving IDDS were lung (27.15%), colorectal (24.9%), liver (16.44%), bone (8.01%), and liver (7.99%) cancer. In addition, the length of stay was six days (interquartile range [IQR] four-nine days) and the median cost of hospital admission was $29,062 (IQR $19,413-$42,261) in the patients who received an IDDS. These factors were greater than those in patients without IDDS. CONCLUSIONS: A very few patients with cancer received IDDS in the US during the study period. Despite recommendations supporting its use, there are significant racial and socioeconomic disparities in IDDS use.

Clinical Considerations for Implanted Neurological Devices in Patients Undergoing Hyperbaric Oxygen Therapy: A Case Report and Review of Manufacturer Guidelines.

Patients with implanted medical devices are increasingly referred for hyperbaric oxygen therapy (HBOT), and the safety of exposing some of these devices to hyperbaric environments has not previously been explored. There is a paucity of evidence surrounding the management of implanted neurological devices such as neurostimulators and intrathecal drug delivery (IDD) pumps in the context of HBOT. However, these devices can be expected to harbor unique risks; for example, vacant space in the reservoir of an implanted IDD pump may change in pressure and volume during the compression and decompression phases of HBOT, resulting in a damaged or dysfunctional device. We present the case of a 27-year-old woman with cerebral palsy referred for HBOT to manage a necrotizing soft tissue infection cultured from a dehiscent abdominal wound at the previous implantation site of an intrathecal baclofen pump. An HBOT protocol was ultimately chosen in partnership with the patient and her family, but treatment was not performed due to a paucity of evidence that the implanted IDD pump could safely withstand hyperbaric exposure. In this review, we have synthesized manufacturer recommendations regarding the management of implanted neurological devices before, during, and after HBOT to inform future decision-making in this setting. Among these recommendations, we highlight that neurostimulators should be switched off for the duration of HBOT and implanted pumps should be refilled prior to each treatment session to minimize empty reservoir space.

Early Interventional Treatments for Patients with Cancer Pain: A Narrative Review.

Between 10% and 20% of patients with cancer-related pain cannot achieve adequate control following the three-step ladder guidelines by the World Health Organization. Therefore, a "fourth step", including interventional approaches, has been suggested for those cases. Systematic reviews support the early use of interventional procedures to treat refractory cancer pain, control symptoms and prevent opioid dose escalation. There is strong evidence of the efficacy of celiac plexus or splanchnic neurolysis, vertebroplasty, kyphoplasty and intrathecal drug delivery. Those procedures have been found to be associated with a decrease in the symptom burden and opioid consumption, improved quality of life, and suggested as having a potentially positive impact on survival. Several studies have recommended using specific interventional techniques at earlier stages, possibly even when opioid treatment is first being considered. Conversely, leaving these options as a last analgesic resource might not be advisable since the burden these procedures might impose on too ill patients is significant. The objective of this review was to collect the available evidence published on the use of interventional treatments for refractory cancer pain with a particular interest in comparing early versus late indications. The results of the search demonstrated a very low number and quality of articles particularly addressing this question. This scarce number of evidence precluded performing a systematic analysis. A detailed and narrative description of the potential benefits of integrating interventional techniques into clinical guidelines at the early stages of the disease is provided.

Intrathecal drug delivery for cancer pain at the end of life: a case study.

Two-thirds of patients with advanced cancer have pain and, of these, approximately 10-20% do not respond to conventional pain management approaches. This case study concerns a hospice patient who received intrathecal drug delivery for intractable cancer pain at the end of life. This involved working in partnership with a hospital-based interventional pain team. Despite side-effects and complications associated with intrathecal drug delivery and the requirement for inpatient nursing care, intrathecal drug delivery was the best option for the patient. The case identifies the importance of a patient-centred approach to decision-making, effective partnerships between hospice and acute hospital teams, and nurse education as key factors contributing to the provision of safe and effective intrathecal drug delivery.

Interventional Pain Procedures: A Narrative Review Focusing On Safety and Complications. PART 2 Interventional Procedures For Back Pain.

In patients where conservative approaches have failed to relieve from chronic pain, interventional procedures may be an option in well selected patients. In recent years there has been an increase in the use and development of invasive procedures. Concomitantly, there has also been an increase in the complications associated with these procedures. Taken this into consideration, it is important for healthcare providers to take a cautious and vigilant approach, with a focus on patient safety, in order to minimize the risk of adverse events and ensure the best possible outcome for the patient. This may include careful selection of patients for procedures, use of proper techniques and equipment, and close monitoring and follow-up after the procedure. The aim of this narrative review is to summarize the primary complications associated with commonly performed image-guided (fluoroscopy or ultrasound-guided) interventional procedures and provide strategies to reduce the risk of these complications. We conclude that although complications from interventional pain procedures can be mitigated to a certain degree, they cannot be eliminated altogether. In order to avoid adverse events, patient safety should be given considerable attention and physicians should be constantly aware of the possibility of developing complications.

Loss of effectiveness with an implanted drug delivery system for intrathecal pain therapy due to corrosion.

INTRODUCTION: Intrathecal drug delivery is an established invasive treatment option. Most common complication is catheter malfunction, which can lead to overdose or withdrawal. CASE PRESENTATION: A 61-year-old female patient underwent an elective replacement of an intrathecal drug delivery pump. The patient complained about a loss of effectiveness over the past 2 years. Intraoperatively, a white mass corresponding to morphine precipitation in the pump pocket was found, which appeared to be due to corrosion at the pump-catheter connection site. CONCLUSIONS: Recommendations on how to deal with the decreasing effectiveness of intrathecal drug delivery and on intraoperative catheter handling are provided.

Efficacy of Continuous Intrathecal Infusion Trialing with a Mixture of Fentanyl and Bupivacaine in Chronic Low Back Pain Patients.

Intrathecal trialing is used as a screening prognostic measure prior to intrathecal drug delivery system implant. The purpose of this study was to determine the efficacy of a continuous intrathecal infusion of an admixture of bupivacaine and fentanyl in patients with chronic low back pain. Patients with refractory chronic low back pain in the setting of previous lumbar spine surgery and/or chronic vertebral compression fracture(s) were enrolled in a randomized double blind cross-over study comparing saline infusion to infusion of a solution containing bupivacaine combined with low-dose fentanyl over a 14-18 hour period. The primary outcome measure was the change in pain intensity at the end of the screening trial. Patients who experienced significant pain reduction from either infusion relative to baseline pain were offered a permanent implant. In total, 36 patients were enrolled, with 31 patients trialed and 25 implanted. At the end of the screening trial, pain scores, at rest or with activity, decreased appreciably in both groups; however, significantly better improvements occurred in the fentanyl/bupivacaine group compared to saline both with activity and at rest (P = .016 and .006, respectively). Treatment order appeared to affect outcome with saline demonstrating a placebo response. At 12 months following implant, primary and secondary outcome measures continued to be significantly reduced from baseline. Continuous intrathecal delivery of a combination of zlow-dose fentanyl with bupivacaine is superior to saline in screening intrathecal trialing for back pain reduction. With longer term delivery, a sustained reduction of chronic low back pain was also observed.