Catheter-based Techniques for Terminal Cancer Pain: A Review of Nonneuraxial Interventions with Clinical Implications for End-of-Life Pain Management.

BACKGROUND: Evidence suggests that a significant proportion of terminal cancer patients have uncontrolled or inadequately controlled pain when using the World Health Organization (WHO) analgesic ladder approach. The use of interventional techniques has proven to reduce pain that is refractory to conventional methods. However, despite the use of well-established techniques (e.g., intrathecal drug delivery, celiac plexus blocks, etc), nonneuraxial, catheter-based techniques remain underutilized. OBJECTIVE: The purpose of this narrative review is to examine the evidence for nonneuraxial, catheter-based techniques in treating terminal cancer pain, the barriers to implementation, and its role in bridging the gap between single shot techniques and surgically implanted devices. STUDY DESIGN: This is a narrative review article summarizing case reports, case series, retrospective studies, prospective studies, and review articles published at any time frame on the use of nonneuraxial, catheter-based techniques for the treatment of cancer pain in the end-of-life setting. SETTING: The University of Texas MD Anderson Cancer Center. METHODS: A literature search was conducted from November 2020 to January 2021 using the PubMed database and keywords related to nonneuraxial catheters, terminal cancer pain, and hospice. All English-based literature published at any time frame involving human patients was included. RESULTS: The number of studies referencing the use of nonneuraxial, catheter-based techniques for the treatment of terminal cancer pain is limited (n = 25). All of these studies were small, single-center, nonrandomized, noncontrolled case series and case reports. A total of 63 patients were evaluated across all studies, with the largest study involving 12 patients. The most common medication used was monotherapy with bupivacaine or ropivacaine and the longest duration of continuous catheter usage was 217 days. Of the studies that reported outcomes, the majority reported a reduction in pain. Very few studies reported catheter-related adverse events and tunneling appeared to be an important factor in reducing complications. LIMITATIONS: No studies were available comparing the use of nonneuraxial, catheter-based techniques to conventional systemic medical management. Further, the studies in this review were heterogenous and limited to a small sample sizes reported in case reports and case series only. CONCLUSION: Nonneuraxial, catheter-based techniques have the potential to play a significant role in the treatment of terminal cancer pain. Despite limited data, initial findings indicate that nonneuraxial, catheter-based techniques have the potential to bridge the gap between single shot interventions and surgical implanted devices by providing an effective, continuous therapy, with a lower risk profile.

Comparison of FDA-Approved Electrical Neuromodulation Techniques for Focal Neuropathic Pain: A Narrative Review of DRG, HF10, and Burst Neuromodulation.

BACKGROUND: Evidence suggests that dorsal root ganglion stimulation (DRGS) is a more effective treatment for focal neuropathic pain (FNP) compared with tonic, paresthesia-based dorsal column spinal cord stimulation (SCS). However, new advancements in waveforms for dorsal column SCS have not been thoroughly studied or compared with DRGS for the treatment of FNP. OBJECTIVES: The purpose of this review was to examine the evidence for these novel technologies; to highlight the lack of high-quality evidence for the use of neuromodulation to treat FNP syndromes other than complex regional pain syndrome I or II of the lower extremity; to emphasize the absence of comparison studies between DRGS, burst SCS, and high-frequency SCS; and to underscore that consideration of all neuromodulation systems is more patient-centric than a one-size-fits-all approach. STUDY DESIGN: This is a review article summarizing case reports, case series, retrospective studies, prospective studies, and review articles. SETTING: The University of Miami, Florida. METHODS: A literature search was conducted from February to March 2020 using the PubMed and EMBASE databases and keywords related to DRGS, burst SCS, HF10 (high-frequency of 10 kHz), and FNP syndromes. All English-based literature from 2010 reporting clinical data in human patients were included. RESULTS: Data for the treatment of FNP using burst SCS and HF10 SCS are limited (n = 11 for burst SCS and n = 11 for HF10 SCS). The majority of these studies were small, single-center, nonrandomized, noncontrolled, retrospective case series and case reports with short follow-up duration. To date, there are only 2 randomized controlled trials for burst and HF10 for the treatment of FNP. LIMITATIONS: No studies were available comparing DRGS to HF10 or burst for the treatment of FNP. Data for the treatment of FNP using HF10 and burst stimulation were limited to a small sample size reported in mostly case reports and case series. CONCLUSIONS: FNP is a complex disease, and familiarity with all available systems allows the greatest chance of success.