Transition from Deep Regional Blocks toward Deep Nerve Hydrodissection in the Upper Body and Torso. Method Description and Results from a Retrospective Chart Review of the Analgesic Effect of 5% Dextrose in Water (D5W) as the Primary Hydrodissection

Abstract

Although low-level studies demonstrate effectiveness of nerve hydrodissection, there are no high level studies to date.4 Prior to high-level study performance, procedural methods must be described that are reproducibly performed, reliable in effect, and safe. The objectives of this article are to illustrate reproducible methods of hydrodissection for upper torso deep nervous structures including the stellate ganglion, brachial plexus, cervical nerve roots and paravertebral spaces, and to gather preliminary data related to an analgesic effect and efficacy of D5W without lidocaine as the primary injectate in hydrodissection for those conditions. A formal letter of exemption allowing retrospective chart review was obtained from the International Cellular Medicine Society Institutional Review Board. (ICMS-IRB). Consecutive charts were reviewed for patients who received hydrodissection of stellate ganglion, brachial plexus, cervical nerve roots, or paravertebral spaces as a treatment method for neuropathic pain, using D5W exclusively, with lidocaine used for skin blebs only. Chart selection continued until data from 100 treatments was available for analysis. Methods of hydrodissection utilized on patients in this consecutive patient data collection were illustrated with use of anatomical diagrams, ultrasound images and videos. The primary measure for a potential intraprocedural analgesia effect of D5W hydrodissection was the mean difference between pre-treatment pain and immediate (5 minute) post-treatment pain in points as measured on a 0-10 Numerical Rating Scale (NRS). The patients were followed-up at two-month post-treatment to inquire about further need for treatment and to obtain a final 0-10 NRS pain level to monitor for treatment efficacy. Data were analyzed using PASW 18 (Predictive Analytics 180 Software 18.0.0, IBM). Descriptive statistics (mean ± standard deviation) were reported at baseline and at each session for NRS. Cumulative improvement in patient’s pain levels over time was determined by calculating the mean difference between pre-treatment patient pain measured at time 0 and post-treatment pain measured 2 months after the last clinic visit. The percentage of cases achieving more than 50% and more than 75% improvement in pain was calculated. A retrospective chart review was performed of treatment results from 100 hydrodissection treatments in 26 consecutive cases (25 patients; one receiving treatment bilaterally) 51±14.7 years of age, with neuropathic pain duration of 16±12.2 months and initial numerical rating scale for pain (NRS 0-10) of 8.3±1.3 points. The mean percentage of analgesia during each treatment session was 88.1±9.8% with injection of D5W without anesthetic. NRS pain levels changed from 8.3±1.3 pre-treatment to 1.9±0.9 two months after the last treatment for a point change improvement of 6.4±1.7 points. Patients received 3.8±2.6 treatments over 9.7±7.8 months from 1st treatment to 2-month-post-treatment follow-up. Pain improvement exceeded 50% in all cases and 75% in half (13/26). An analgesic effect of D5W injection is confirmed by this study and a cumulative pain reduction is suggested. This article has illustrated potentially-reproducible methods of hydrodissection for stellate ganglion, brachial plexus, cervical nerve roots and paravertebral spaces, provides data supporting a consistent analgesic effect of D5W and suggests a potentially sustainable clinical benefit in patients with chronic upper back/thorax pain of neuropathic origin. The mechanism of analgesia may relate to an indirect (allosteric) effect on the TRPV1 cation channel, hyperpolarization of normoglycemic C fibers, correction of local neural hypoglycemia, or undiscovered, likely multiple, mechanisms. The well-developed chronic constriction injury model, which results in neuropathic pain and neural swelling, is the primary rationale behind hydrodissection of nerves to release the nerve from suspected local neural compression, particularly for those nerves with fascicular nerve swelling or an increase in overall neural volume. The frequency of neural edema and the long-term efficacy of nerve hydrodissection in neuropathic pain, in contrast to anesthetic low volume nerve block, are important foci of future research in neuropathic pain conditions.