Twelve-month results from a randomized controlled trial comparing differential target multiplexed spinal cord stimulation and conventional spinal cord stimulation in subjects with chronic refractory axial low back pain not eligible for spine surgery.

Background: Successful treatments for intractable chronic low back pain (CLBP) in patients who are not eligible for surgical interventions are scarce. The superior efficacy of differential target multiplexed spinal cord stimulation (DTM SCS) to conventional SCS (Conv-SCS) on the treatment of CLBP in patients with persistent spinal pain syndrome (PSPS) who have failed surgical interventions (PSPS-T2) motivated the evaluation of DTM SCS versus Conv-SCS on PSPS patients who are non-surgical candidates (PSPS-T1). Methods: This is a prospective, open label, crossover, post-market randomized controlled trial in 20 centers across the United States. Eligible patients were randomized to either DTM SCS or Conv-SCS in a 1:1 ratio. Primary endpoint was CLBP responder rate (percentage of subjects with ≥50% CLBP relief) at 3-month in randomized subjects who completed trialing (modified intention-to-treat population). Patients were followed up to 12 months. Secondary endpoints included change of CLBP and leg pain, responder rates, changes in disability, quality of life, patient satisfaction and global impression of change, and safety profile. An optional crossover was available at 6-month to all patients. Results: About 121 PSPS-T1 subjects with CLBP and leg pain mostly associated with degenerative disc disease and radiculopathy and who were not eligible for spine surgery were randomized. CLBP responder rate with DTM SCS (93.5%) was superior to Conv-SCS (36.4%) at the primary endpoint. Superior CLBP responder rates (88.1%-90.5%) were obtained with DTM SCS at all other timepoints. Mean CLBP reduction with DTM SCS (6.52 cm) was superior to that with Conv-SCS (3.01 cm) at the primary endpoint. Similar CLBP reductions (6.23-6.43 cm) were obtained with DTM SCS at other timepoints. DTM SCS provided significantly better leg pain reduction and responder rate, improvement of disability and quality of life, and better patient satisfaction and global impression of change. 90.9% of Conv-SCS subjects who crossed over were CLBP responders at completion of the study. Similar safety profiles were observed between the two groups. Conclusion: DTM SCS for chronic CLBP in nonsurgical candidates is superior to Conv-SCS. Improvements were sustained and provided significant benefits on the management of these patients.

Characteristics of phantom limb pain in U.S. civilians and service members.

OBJECTIVES: The population of Americans with limb loss is on the rise, with a different profile than in previous generations (e.g., greater incidence of amputation due to diabetes). This study aimed to identify the key characteristics of phantom limb sensation (PLS) and pain (PLP) in a current sample of Americans with limb loss. METHODS: This cross-sectional study is the first large-scale (n=649) study on PLP in the current population of Americans with limb loss. A convenience sample of military and civilian persons missing one or more major limbs was surveyed regarding their health history and experience with phantom limb phenomena. RESULTS: Of the participants surveyed, 87% experienced PLS and 82% experienced PLP. PLS and PLP typically first occurred immediately after amputation (47% of cases), but for a small percentage (3-4%) onset did not occur until over a year after amputation. Recent PLP severity decreased over time (ß=0.028, 95% CI: -0.05-0.11), but most participants reported PLP even 10 years after amputation. Higher levels of recent PLP were associated with telescoping (ß=0.123, 95% CI: 0.04-0.21) and higher levels of pre-amputation pain (ß=0.104, 95% CI: 0.03-0.18). Those with congenitally missing limbs experienced lower levels of recent PLP (t (37.93)=3.93, p<0.01) but there were no consistent differences in PLP between other amputation etiologies. CONCLUSIONS: Phantom limb phenomena are common and enduring. Telescoping and pre-amputation pain are associated with higher PLP. Persons with congenitally missing limbs experience lower levels of PLP than those with amputation(s), yet PLP is common even in this subpopulation.

Intradiscal quantitative chemical exchange saturation transfer MRI signal correlates with discogenic pain in human patients.

Low back pain (LBP) is often a result of a degenerative process in the intervertebral disc. The precise origin of discogenic pain is diagnosed by the invasive procedure of provocative discography (PD). Previously, we developed quantitative chemical exchange saturation transfer (qCEST) magnetic resonance imaging (MRI) to detect pH as a biomarker for discogenic pain. Based on these findings we initiated a clinical study with the goal to evaluate the correlation between qCEST values and PD results in LBP patients. Twenty five volunteers with chronic low back pain were subjected to T2-weighted (T2w) and qCEST MRI scans followed by PD. A total of 72 discs were analyzed. The average qCEST signal value of painful discs was significantly higher than non-painful discs (p = 0.012). The ratio between qCEST and normalized T2w was found to be significantly higher in painful discs compared to non-painful discs (p = 0.0022). A receiver operating characteristics (ROC) analysis indicated that qCEST/T2w ratio could be used to differentiate between painful and non-painful discs with 78% sensitivity and 81% specificity. The results of the study suggest that qCEST could be used for the diagnosis of discogenic pain, in conjunction with the commonly used T2w scan.

Scrambler Therapy Treatment: The Importance of Examining Clinically Meaningful Improvements in Chronic Pain and Quality of Life.

INTRODUCTION: Calmare Scrambler Therapy (ST) interferes with pain signal transmission by using nerve fibers to convey a message of normality to the central nervous system. This prospective, double-blinded, randomized trial had three aims. First, we tried to determine ST's effectiveness in reducing chronic neuropathic pain symptoms and analgesic medication use in military service members, when compared to sham treatment. Next, we examined its effect on reported mental and physical health-related quality of life. Finally, we sought to describe participant perceptions of treatment effectiveness. MATERIALS AND METHODS: Forty-seven subjects were randomized to receive ten 30-minute active ST or sham treatments. Data were collected at baseline, posttreatment, and 1-month follow-up. RESULTS: The groups showed no statistically significant differences in pain scores, medication use, or mental or physical health-related quality of life with active versus sham treatment. However, both produced clinically meaningful reductions in pain and improvements in physical health-related quality posttreatment that was sustained at 1-month follow-up. Ninety percent of the blinded sample described the treatment intervention as a partial or complete success. CONCLUSION: ST is no better than sham treatment in decreasing pain. Yet, patient perceptions of treatment effectiveness are equally important in chronic pain treatment.

Prospective cohort study examining the use of regional anesthesia for early pain management after combat-related extremity injury.

BACKGROUND: No studies have examined the long-term benefits of regional anesthesia (RA) for pain management after combat-related injury. The objective of this prospective cohort study was to examine the relationship between RA administration and patient-reported pain-related outcomes among Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) service members sustaining a combat-related extremity injury. METHODS: Between 2007 and 2013, n=358 American military personnel injured in OEF/OIF were enrolled at two military treatment facilities. Individuals were followed for up to 2 years after injury. Cohorts were defined based on whether participants were administered RA within 7 days after sustaining a combat-related injury, or not. Linear mixed effects models examined the association between RA and average pain intensity. Secondary outcomes included pain relief, pain interference, neuropathic pain symptoms, treatment outcomes related to pain management, and mental health symptoms. RESULTS: Receiving early RA was associated with improved average pain over the first 6 months after injury (ß=-0.57; p=0.012) adjusting for injury severity and length of stay at the primary treatment facility. This difference was observed up to 24 months after injury (ß=-0.36; p=0.046). Individuals receiving early RA reported greater pain relief, improved neuropathic pain intensity, and higher satisfaction with pain outcomes; however, by 24 months, mean scores did not significantly differ between cohorts. CONCLUSION: Findings indicate that when administered soon after traumatic injury, RA is a valuable pain management intervention. Future longitudinal studies investigating the timely delivery of RA for optimal pain management in civilian trauma settings are needed. TRIAL REGISTRATION NUMBER: NCT00431847.

Upper Extremity Amputation and Prosthetics Care Across the Active Duty Military and Veteran Populations.

The hand and arm are exceptionally dexterous, exquisitely sensitive, and proficient in performing tasks and functions. Given the invaluable functions of the upper extremity in daily life, replacement of a missing limb through prosthetic substitution is challenging. Prosthetic and rehabilitation needs of injured Service members from recent military conflicts have brought upper extremity amputation to the forefront, which has led to an increase in attention and resource allocation. This article provides an overview of the care of the upper extremity amputee including surgical considerations, prosthetic design and fitting, and preprosthetic and post-prosthetic rehabilitation considerations.

The effect of pulsed electromagnetic frequency therapy on health-related quality of life in military service members with chronic low back pain.

BACKGROUND: In the U.S. military, chronic low back pain is among the most frequent complaints for medical visits, lost work time, and attrition from active duty and the deployed setting by service members. PURPOSE: The aim of this pilot study was to determine whether adjunctive treatment with pulsed electromagnetic frequency (PEMF) produced significant variability in chronic low back pain symptoms and secondary health-related quality of life, mental health and disability outcomes. METHODS: Prospective, randomized pilot study with repeated measures at baseline, post-treatment, and 1 month follow-up for two groups: usual care (UC) vs. UC + PEMF. FINDINGS: In a convenience sample of 75 service members, health-related quality of life mental and physical component scores were significant: F(2, 104) = 4.20, p = .018 (η2 = .075) and F(2, 104) = 4.75, p = .011 (η2 = .084), respectively; as was anxiety symptom severity: F(2, 104) = 5.28, p = .007 (η2 = .092). DISCUSSION AND RECOMMENDATIONS: Adjunctive treatment with PEMF demonstrated improvements in service members' overall physical health-related quality of life with expected, yet statistically nonsignificant improvements in reported pain and LBP-related disability. There were significant between group differences in anxiety symptom severity with higher symptoms reported by the UC + PEMF group, surprising findings that warrant further investigation.

Improving Pain Management and Long-Term Outcomes Following High-Energy Orthopaedic Trauma (Pain Study).

Poor pain control after orthopaedic trauma is a predictor of physical disability and numerous negative long-term outcomes. Despite increased awareness of the negative consequences of poorly controlled pain, analgesic therapy among hospitalized patients after orthopaedic trauma remains inconsistent and often inadequate. The Pain study is a 3 armed, prospective, double-blind, multicenter randomized trial designed to evaluate the effect of standard pain management versus standard pain management plus perioperative nonsteroidal anti-inflammatory drugs or pregabalin in patients of ages 18-85 with extremity fractures. The primary outcomes are chronic pain, opioid utilization during the 48 hours after definitive fixation and surgery for nonunion in the year after fixation. Secondary outcomes include preoperative and postoperative pain intensity, adverse events and complications, physical function, depression, and post-traumatic stress disorder. One year treatment costs are also compared between the groups.

Economic Impact of Ketorolac vs Corticosteroid Intra-Articular Knee Injections for Osteoarthritis: A Randomized, Double-Blind, Prospective Study.

BACKGROUND: Knee osteoarthritis is a disabling disease that costs billions of dollars to treat. Corticosteroid gives varying pain relief and costs $12 per injection, whereas ketorolac costs $2 per injection, per institutional costs. The aim of this study was to compare ketorolac with corticosteroid based on pain relief using patient outcome measures and cost data. METHODS: A total of 35 patients were randomized to ketorolac or corticosteroid intra-articular knee injection in a double-blind, prospective study. Follow-up was 24 weeks. Osteoarthritis was evaluated using Kellgren-Lawrence grading. Visual analog scale (VAS) was the primary outcome measure. A query of the institutional database was performed for International Classification of Diseases, Ninth Revision codes 715.16 and 719.46, and procedure code 20610 over a 3-year period. Two-way, repeated measures analysis of variance and Spearman rank correlation were used for statistical analysis. RESULTS: Mean VAS for ketorolac and corticosteroid decreased significantly from baseline at 2 weeks, 6.3-4.6 and 5.2-3.6, respectively and remained decreased for 24 weeks. There was no correlation between VAS and demographics within treatments. There were 220, 602, and 405 injections performed on patients with the International Classification of Diseases, Ninth Revision codes 715.16 and 719.46 during 2013, 2014, and 2015, respectively. The cost savings per year using ketorolac instead of corticosteroid would be $2259.40, $6182.54, and $4159.35 for 2013, 2014, and 2015, respectively, with a total savings of $12,601.29 over this period. CONCLUSION: Pain relief was similar between ketorolac and corticosteroid injections. Ketorolac knee injection is safe and effective with a cost savings percentage difference of 143% when compared with corticosteroid.

Immediate Return to Ambulation and Improved Functional Capacity for Rehabilitation in Complex Regional Pain Syndrome following Early Implantation of a Spinal Cord Stimulation System.

Complex regional pain syndrome (CRPS) is a neuropathic pain condition that is characterized by vasomotor, sensory, sudomotor, and motor symptoms. Spinal cord stimulation (SCS) has been successfully utilized for the treatment of pain refractory to conventional therapies. We present a case of a previously highly functioning 54-year-old female who developed a rarely reported case of idiopathic CRPS of the right ankle which spontaneously occurred four months after an uncomplicated anterior cervical disc fusion. This condition resulted in severe pain and functional impairment that was unresponsive to pharmacological management. The patient's rehabilitation was severely stymied by her excruciating pain. However, with the initiation of spinal cord stimulation, her pain was adequately controlled allowing for progression to full unassisted ambulation, advancing functional capacity, and improving quality of life. This case report supports the concept that rapid progression to neuromodulation, rather than delays that occur due to attempts at serial sympathetic blocks, may better control symptoms leading allowing for a more meaningful recovery.

Ultrasound-guided greater occipital nerve blocks and pulsed radiofrequency ablation for diagnosis and treatment of occipital neuralgia.

Occipital neuralgia is a condition manifested by chronic occipital headaches and is thought to be caused by irritation or trauma to the greater occipital nerve (GON). Treatment for occipital neuralgia includes medications, nerve blocks, and pulsed radiofrequency ablation (PRFA). Landmark-guided GON blocks are the mainstay in both the diagnosis and treatment of occipital neuralgia. Ultrasound is being utilized more and more in the chronic pain clinic to guide needle advancement when performing procedures; however, there are no reports of ultrasound used to guide a diagnostic block or PRFA of the GON. We report two cases in which ultrasound was used to guide diagnostic greater occipital nerve blocks and greater occipital nerve pulsed radiofrequency ablation for treatment of occipital neuralgia. Two patients with occipital headaches are presented. In Case 1, ultrasound was used to guide diagnostic blocks of the greater occipital nerves. In Case 2, ultrasound was utilized to guide placement of radiofrequency probes for pulsed radiofrequency ablation of the greater occipital nerves. Both patients reported immediate, significant pain relief, with continued pain relief for several months. Further study is needed to examine any difference in outcomes or morbidity between the traditional landmark method versus ultrasound-guided blocks and pulsed radiofrequency ablation of the greater occipital nerves.

Establishing an optimal "cutoff" threshold for diagnostic lumbar facet blocks: a prospective correlational study.

OBJECTIVES: Diagnostic medial branch blocks (MBB) are considered the reference standard for diagnosing facetogenic pain and selecting patients for radiofrequency (RF) denervation. Great controversy exists regarding the ideal cutoff for designating a block as positive. The purpose of this study is to determine the optimal pain relief threshold for selecting patients for RF denervation after diagnostic MBB. METHODS: In this multicenter, prospective correlational study, 61 consecutive patients undergoing lumbar facet RF denervation after experiencing significant pain relief after MBB were enrolled. A positive outcome was defined as a ≥50% reduction in back pain at rest or with activity coupled with a positive satisfaction score lasting longer than 3 months. The relationship between pain relief after the blocks and denervation outcomes was evaluated by pairwise correlation matrix, receiver's operating characteristic curve, and stratifying outcomes based on 10- and 17-percentage point intervals for MBB. RESULTS: There were no significant differences in RF outcomes based on any MBB pain relief cutoff over 50%. A trend was noted whereby those patients who obtained <50% pain relief reported poorer outcomes. No optimal threshold for designating a diagnostic block as positive, above 50% pain relief, could be calculated. CONCLUSION: Employing more stringent selection criteria for lumbar facet RF is likely to result in withholding a beneficial procedure from a substantial number of patients, without improving success rates.

Painful sequelae following limb salvage: etiology and management.

Inadequately controlled pain is a significant problem during limb salvage and is associated with poor outcomes. This pain has several causes, and many management options exist. Chronic pain associated with limb salvage causes unnecessary suffering and negatively affects long-term function. Chronic pain and disability in this population may be prevented with early, aggressive, comprehensive treatment. Ongoing research into the cause and clinical course of limb salvage pain likely will lead to advances in pain management and functional improvement.