Percutaneous Neuromodulation of the Brachial Plexus and Sciatic Nerve for the Treatment of Acute Pain Following Surgery: Secondary Outcomes From a Multicenter, Randomized, Controlled Pilot Study.

OBJECTIVES: We recently reported that percutaneous peripheral nerve stimulation (PNS or "neuromodulation") decreased pain and opioid consumption within the first two weeks following ambulatory surgery. However, the anatomic lead locations were combined for the analysis, and benefits for each location remain unknown. We therefore now report the effects of percutaneous PNS for brachial plexus and sciatic nerve leads separately. MATERIALS AND METHODS: Before surgery, leads were implanted percutaneously to target the brachial plexus (N = 21) for rotator cuff repair or sciatic nerve (N = 40) for foot/ankle surgery, followed by a single injection of local anesthetic. Postoperatively, subjects were randomized in a double masked fashion to 14 days of electrical stimulation (N = 30) or sham/placebo (N = 31) using an external pulse generator. The primary outcome of interest was opioid consumption and pain scores evaluated jointly. Thus, stimulation was deemed effective if superior on either outcome and at least noninferior on the other. RESULTS: For brachial plexus leads, during the first seven postoperative days pain measured with the numeric rating scale in participants given active stimulation was a median [interquartile range] of 0.8 [0.5, 1.6] versus 3.2 [2.7, 3.5] in patients given sham (p < 0.001). For this same group, opioid consumption in participants given active stimulation was 10 mg [5, 20] versus 71 mg [35, 125] in patients given sham (p = 0.043). For sciatic nerve leads, pain scores for the active treatment group were 0.7 [0, 1.4] versus 2.8 [1.6, 4.6] in patients given sham (p < 0.001). During this same period, participants given active stimulation consumed 5 mg [0, 30] of opioids versus 40 mg [20, 105] in patients given sham (p = 0.004). Treatment effects did not differ statistically between the two locations. CONCLUSIONS: Ambulatory percutaneous PNS of both the brachial plexus and sciatic nerve is an effective treatment for acute pain free of systemic side effects following painful orthopedic surgery.

Percutaneous Peripheral Nerve Stimulation (Neuromodulation) for Postoperative Pain: A Randomized, Sham-controlled Pilot Study.

BACKGROUND: Percutaneous peripheral nerve stimulation is an analgesic technique involving the percutaneous implantation of a lead followed by the delivery of electric current using an external pulse generator. Percutaneous peripheral nerve stimulation has been used extensively for chronic pain, but only uncontrolled series have been published for acute postoperative pain. The current multicenter study was undertaken to (1) determine the feasibility and optimize the protocol for a subsequent clinical trial and (2) estimate the treatment effect of percutaneous peripheral nerve stimulation on postoperative pain and opioid consumption. METHODS: Preoperatively, an electrical lead was percutaneously implanted to target the sciatic nerve for major foot/ankle surgery (e.g., hallux valgus correction), the femoral nerve for anterior cruciate ligament reconstruction, or the brachial plexus for rotator cuff repair, followed by a single injection of long-acting local anesthetic along the same nerve/plexus. Postoperatively, participants were randomized to 14 days of either electrical stimulation (n = 32) or sham stimulation (n = 34) using an external pulse generator in a double-masked fashion. The dual primary treatment effect outcome measures were (1) cumulative opioid consumption (in oral morphine equivalents) and (2) mean values of the "average" daily pain scores measured on the 0 to 10 Numeric Rating Scale within the first 7 postoperative days. RESULTS: During the first 7 postoperative days, opioid consumption in participants given active stimulation was a median (interquartile range) of 5 mg (0 to 30) versus 48 mg (25 to 90) in patients given sham treatment (ratio of geometric means, 0.20 [97.5% CI, 0.07 to 0.57]; P < 0.001). During this same period, the average pain intensity in patients given active stimulation was a mean ± SD of 1.1 ± 1.1 versus 3.1 ± 1.7 in those given sham (difference, -1.8 [97.5% CI, -2.6 to -0.9]; P < 0.001). CONCLUSIONS: Percutaneous peripheral nerve stimulation reduced pain scores and opioid requirements free of systemic side effects during at least the initial week after ambulatory orthopedic surgery.

Ultrasound-Guided Percutaneous Peripheral Nerve Stimulation: A Pragmatic Effectiveness Trial of a Nonpharmacologic Alternative for the Treatment of Postoperative Pain.

BACKGROUND: Percutaneous peripheral nerve stimulation (PNS) is an analgesic modality involving the insertion of a lead through an introducer needle followed by the delivery of electric current after needle withdrawal. This modality has been used extensively to treat chronic pain, but only small series have been published involving postoperative pain. The ultimate objective of this study is to determine the postoperative effects of percutaneous PNS following moderately to severely painful ambulatory surgery within a real-world clinical practice setting. The primary hypothesis is that surgical pain and opioid consumption during the initial 7 days after surgery will be reduced by percutaneous PNS compared with usual and customary analgesia (dual primary outcome measures). DESIGN: A multicenter pragmatic effectiveness trial. We are randomizing participants having painful orthopedic surgical procedures of the upper and lower extremity to receive 14 days of either 1) electrical stimulation or 2) sham in a double-masked fashion. End points are being assessed at various time points over 12 postoperative months. SUMMARY: The postoperative experience will be much improved if percutaneous PNS provides potent analgesia while concurrently decreasing opioid requirements following painful surgery. Because this modality can be administered for up to 60 days at home, it may provide postoperative analgesia that outlasts surgical pain yet has relatively few risks and, unlike opioids, has no systemic side effects or potential for abuse, addiction, and overdose. Percutaneous PNS has the potential to revolutionize postoperative analgesia as it has been practiced for the past century. This study will inform key stakeholders regarding an evidence-based nonpharmacologic approach to the management of postoperative pain.

The Intraoperative Effect of Methadone on Somatosensory Evoked Potentials.

BACKGROUND: Evoked potentials (EP), both somatosensory evoked potentials (SSEP) and transcranial motor evoked potentials (TcMEP), are often used during complex spine surgery to monitor the integrity of spinal pathways during operations in or around the spine. Changes in these monitored EP signals (increased latency and decreased amplitude) may result from ischemia, direct surgical injury, changes in blood pressure, hypoxia, changes in CO2 tension, and anesthetic agents. Typically, a clinically significant change for SSEPs is defined as an increase in latency >10% or a decrease of amplitude >50%. A clinically significant change for TcMEPs is much more complex but is also described in terms of large signal loss or decrease. Opioids have been shown to both increase latency and decrease the amplitude of SSEPs, although this change is usually not clinically significant. There has been a renewed interest in methadone for use in spine and other complex surgeries. However, the effect of methadone on intraoperative monitoring of SSEPs and TcMEPs is unknown. We present the first study to directly look at the effects of methadone on SSEP and TcMEP monitoring during complex spine surgery. METHODS: The goal of this study was to observe the effect of methadone on an unrandomized set of patients. The primary endpoint was methadone's effect on SSEPs, and the secondary endpoint was methadone's effect on TcMEPs. Adult patients undergoing spine surgery requiring intraoperative neuromonitoring were induced with general anesthesia and had a baseline set of SSEPs and TcMEPs recorded. Next, methadone dosed 0.2 mg/kg/lean body weight was given. Repeat SSEPs and TcMEPs were recorded at 5, 10, and 15 minutes, with the timing based on distribution half-life of methadone between 6 and 8 minutes. Postoperatively, adverse events from methadone administration were collected. RESULTS: There was a statistically significant difference found in SSEPs for N20 latency (95% confidence interval [CI], 0.17-0.53; P=0.028), P37 latency (95% CI, 0.65-1.25; P=0.001), and N20 amplitude (95% CI, 0.09-0.32; P=<0.001), but not for P37 amplitude (95% CI, -0.19 to 0.00; P=0.634). There was no significant effect found for TcMEPs, the secondary endpoint of the study, and there were minimal adverse events recorded postoperatively. CONCLUSIONS: The data demonstrate that a single intravenous dose of methadone has a statistically significant difference on the amplitude and latency of SSEPs. However, this statistical difference does not translate into a clinical significance.

Retrospective analysis of quality improvement when using liposome bupivacaine for postoperative pain control.

BACKGROUND/OBJECTIVE: Liposome bupivacaine, a prolonged-release bupivacaine formulation, recently became available at the Naval Medical Center San Diego (NMCSD); before availability, postsurgical pain for large thoracic/abdominal procedures was primarily managed with opioids with/without continuous thoracic epidural (CTE) anesthesia. This retrospective chart review was part of a clinical quality initiative to determine whether postsurgical outcomes improved after liposome bupivacaine became available. METHODS: Data from patients who underwent laparotomy, sternotomy, or thoracotomy at NMCSD from May 2013 to May 2014 (after liposome bupivacaine treatment became available) were compared with data from patients who underwent these same procedures from December 2011 to May 2012 (before liposome bupivacaine treatment became available). Collected data included demographics, postoperative pain control methods, opioid consumption, perioperative pain scores, and lengths of intensive care unit and overall hospital stays. RESULTS: Data from 182 patients were collected: 88 pre-liposome bupivacaine (laparotomy, n=52; sternotomy, n=26; and thoracotomy, n=10) and 94 post-liposome bupivacaine (laparotomy, n=49; sternotomy, n=31; and thoracotomy, n=14) records. Mean hospital stay was 7.0 vs 5.8 days (P=0.009) in the pre- and post-liposome bupivacaine groups, respectively, and mean highest reported postoperative pain score was 7.1 vs 6.2 (P=0.007), respectively. No other significant between-group differences were observed for the overall population. In the laparotomy subgroup, there was a reduction in the proportion of patients who received CTE anesthesia post-liposome bupivacaine (22% [11/49] vs 35% [18/52] pre-liposome bupivacaine). CONCLUSION: Surgeons and anesthesiologists have changed the way they manage postoperative pain since the time point that liposome bupivacaine was introduced at NMCSD. Our findings suggest that utilization of liposome bupivacaine may be a useful alternative to epidural anesthesia.

Stellate Ganglion Block for the Treatment of Posttraumatic Stress Disorder: A Randomized, Double-Blind, Controlled Trial.

OBJECTIVE: In this study, we aimed to determine if stellate ganglion block (SGB) could reduce symptoms of posttraumatic stress disorder (PTSD) in comparison with sham therapy in military service members. METHODS: In a randomized trial in which both participants and assessors were blind, participants with PTSD received either an SGB or a sham procedure. Posttraumatic stress disorder symptoms were measured using the CAPS (Clinician-Administered PTSD Scale) and self-report measures of PTSD, depression, anxiety, and pain. Subjects underwent assessment before the procedure and at 1 week, 1 month, and 3 months after the procedure. Patients receiving sham injections were allowed to cross over to the treatment group, and participants who maintained criteria for PTSD were allowed to receive a second SGB treatment. RESULTS: Posttraumatic stress disorder, anxiety, and depression scores all showed improvement across time, but there was no statistically or clinically relevant difference in outcomes between the active and control groups. Individuals who crossed over from sham treatment to SGB similarly showed no greater improvement with the SGB treatment. Improvement in CAPS was greater with a second SGB treatment than after the first treatment. CONCLUSIONS: Although previous case series have suggested that SGB offers an effective intervention for PTSD, this study did not demonstrate any appreciable difference between SGB and sham treatment on psychological or pain outcomes. Future studies should examine if differences in treatment methods or patient population could allow individuals with PTSD to benefit from SGB, but current evidence does not support widespread or indiscriminant clinical use of the procedure for PTSD.

Computed tomographic-guided genitofemoral nerve block: a simple anterior approach.

Chronic groin pain, often as a consequence from surgery, is a challenge from both a diagnostic and treatment standpoint. Interventional therapy is often attempted.Genitofemoral nerve block can be used for the diagnosis and treatment of groin pain. Classically, this nerve is blocked blindly at the level of the pubic tubercle, or more recently, with ultrasound. We present a novel technique to blocking the genitofemoral nerve in males using an anterior approach with computed tomographic guidance.

A comparison of ultrasound-guided and landmark-based approaches to saphenous nerve blockade: a prospective, controlled, blinded, crossover trial.

BACKGROUND: Blockade of the saphenous nerve is often used for surgeries below the knee. Depending on the approach, success rates vary widely ranging from 33% to 88%. In this prospective volunteer study, we compared 2 ultrasound-guided techniques, the modified vastus medialis and perifemoral saphenous nerve block with a below the knee field block. METHODS: Twenty volunteer adults, in a single-blinded, crossover, prospective trial underwent 3 different saphenous nerve blocks. The primary end point of block success was loss of sensation in the distal two-thirds distribution of the saphenous nerve. Secondary variables included time to perform the block, time to sensory loss, pain during block, and motor weakness. RESULTS: Compared with the below the knee field block success rate (30%), both the modified vastus medialis and perifemoral techniques had significantly higher success rates (80%, difference 50% with confidence interval [CI], 23%-77%, P = 0.009, and 100%, difference 70% with CI, 41%-91%, P < 0.001, respectively). However, the difference when comparing the perifemoral ultrasound technique against the modified vastus medialis ultrasound technique did not show significance (difference 20% with CI, -7% to 49%, P = 0.125). Also, no statistical differences were found with the other variables measured, except the perifemoral technique showed faster block performance times than below the knee field block (P = 0.007). CONCLUSION: In our prospective study, we have demonstrated that ultrasound-guided above the knee saphenous nerve blocks have higher success rates than a below the knee field block and are easily performed in a short amount of time.

Profound pain reduction after induction of memantine treatment in two patients with severe phantom limb pain.

We present the cases of two patients who suffered severe lower extremity injuries and subsequently developed phantom limb pain (PLP) that was refractory to high dose opioids and adjunctive pain medications. Both patients were receiving large doses of oral methadone, IV hydromorphone via a patient-controlled analgesia delivery system, and adjunctive medications including tricyclic antidepressants, nonsteroidal anti-inflammatory medications, and anti-epileptics. Despite these treatments, the patients had severe PLP. Upon induction of the oral N-methyl-D-aspartate receptor antagonist memantine, both patients had a profound reduction in their PLP without any apparent side effects from the medication.