Maxim S. Eckmann

Intravenous regional ketorolac and lidocaine in the treatment of complex regional pain syndrome of the lower extremity: a randomized, double-blinded, crossover study.

Background and ObjectivesIntravenous regional blocks (IVRBs) with ketorolac and lidocaine have been reported to be useful in the treatment of complex regional pain syndrome (CRPS). This is the first controlled prospective study of IVRB with lidocaine and ketorolac for treatment of pain and edema in CRPS of the lower extremity in adults. MethodsA prospective, randomized, double-blinded, crossover design was used. The primary outcome was overall pain numeric rating scale (NRS) at 1 week postinjection; secondary outcomes included pain with motion, allodynia, joint pain score, edema, range of ankle motion, skin temperature, and short-term pain relief. Ten of 12 adult patients diagnosed with unilateral lower extremity CRPS (type I) completed the study. Four IVRBs were performed 1 week apart in a random sequence with 50 mL lidocaine 0.5% and 0, 30, 60, and 120 mg ketorolac. ResultsOnly 1 outcome achieved significant improvement; there was 1 day of significant pain reduction in the ketorolac groups (median NRS 6 to 4, P=0.002). Overall pain NRS (10-point scale, mean±SE) at 1 week was 6.2±0.53, 6.5±0.89, 6.0±0.88, 5.9±0.82, and 5.8±0.9 at baseline, 0, 30, 60, and 120 mg, respectively (P=0.8). Pain with movement was 7.15±0.69, 5.7±1.07, 6.1±0.86, 5.0±0.97, and 5.6±0.86, (P=0.059). Edema was not significantly reduced (2% reduction, P=0.6). ConclusionsIVRB with ketorolac and lidocaine produced only short-term pain reduction in patients with CRPS involving the lower extremity after 4 serial injections in our study group. Prospective study is warranted, particularly in the pediatric population.

Radiofrequency Ablation Near the Bone-Muscle Interface Alters Soft Tissue Lesion Dimensions

Background and Objectives Radiofrequency (RF) lesions are safe and effective in the treatment of spine pain; however, models developed to study factors affecting lesion dimensions have been performed in homogeneous media that may not accurately simulate human anatomy and electrophysiology. We present a novel ex vivo porcine model for performing RF lesion studies and report the influence of bone on projection of RF ablation lesions into soft tissue. Methods Radiofrequency lesions were performed in porcine rib specimens using monopolar 18-gauge, 10-mm straight active tip cannula, with a lesion temperature of 80°C for 150 seconds. Ten lesions were performed in pure porcine muscle tissue and abutting porcine rib bone with surrounding muscle. Lesions were exposed with dissection and measured with digital calipers. Results Maximal effective lesion radius approximately doubled against the bone compared with the pure muscle group (mean, 5.65 mm [95% CI, 5.43–5.87 mm] vs 2.68 mm [95% CI, 2.55–2.81 mm], P < .0001), although this was seen only in a vertical direction and not horizontally. In addition, the prelesion and postlesion impedance of the bone-muscle interface was consistently higher than the muscle-only interface (mean, 165.6 Ohm [95% CI, 146.6–184.6 Ohm] vs 137.8 Ohm [95% CI, 135.5–140.1 Ohm], P = 0.004; 144.3 Ohm [95% CI, 134.3–154.3 Ohm] vs 124.3 Ohm [95% CI, 119.3–129.3 Ohm], P = 0.001). Other dimensions and estimated volume were not significantly different. Conclusions Bone adjacent to RF lesions alters the surrounding electrophysiological environment causing RF lesions to project further perpendicularly from the needle axis, vertically to bone, than previously expected. This phenomenon should be considered in the future modeling and clinical practice of RF.

effect of delayed intrathecal administration of capsaicin on neuropathic pain induced by chronic constriction injury of the sciatic nerve in rats

Purpose The current study was designed to examine the antinociceptive effect of intrathecally administered capsaicin, a transient receptor potential vanilloid 1 receptor agonist, in a rat model of neuropathic pain induced by unilateral sciatic nerve chronic constriction injury. Methods Male adult Sprague Dawley rats were randomly assigned to six groups, and all rats underwent unilateral sciatic nerve chronic constriction injury. Two weeks after injury, five groups received intrathecal administration of either capsaicin in three different dosing regimens or equal volumes of vehicle. The other group received intrathecal capsaicin on the third day after nerve injury. The antinociceptive effect of capsaicin was assessed by measuring the capsaicin-induced change in thermal and mechanical response thresholds. Results Capsaicin (150–300 μg/100–200 μL), when administered by fast infusion or chronic infusions at 8 μL/hour or 1 μL/hour, attenuated thermal hyperalgesia as indicated by significantly prolonging paw withdrawal latency to noxious thermal stimulation. The antinociceptive effect of capsaicin was more profound in the injured limb compared to that in the uninjured limb. When capsaicin was administered on the third day after nerve injury, it failed to attenuate thermal hyperalgesia. No significant effect on the mechanical response threshold was observed with intrathecally administered capsaicin. Conclusion Our data suggest that intrathecal capsaicin could significantly attenuate thermal hyperalgesia, depending on the time when the drug is given after nerve injury, and that the antinociceptive efficacy of intrathecal capsaicin positively correlates with the previously reported dynamic profile of spinal transient receptor potential vanilloid 1 activity after nerve injury.

Cadaveric Study of the Articular Branches of the Shoulder Joint

Background and Objectives This cadaveric study investigated the anatomic relationships of the articular branches of the suprascapular (SN), axillary (AN), and lateral pectoral nerves (LPN), which are potential targets for shoulder analgesia. Methods Sixteen embalmed cadavers and 1 unembalmed cadaver, including 33 shoulders total, were dissected. Following dissections, fluoroscopic images were taken to propose an anatomical landmark to be used in shoulder articular branch blockade. Results Thirty-three shoulders from 17 total cadavers were studied. In a series of 16 shoulders, 16 (100%) of 16 had an intact SN branch innervating the posterior head of the humerus and shoulder capsule. Suprascapular sensory branches coursed laterally from the spinoglenoid notch then toward the glenohumeral joint capsule posteriorly. Axillary nerve articular branches innervated the posterolateral head of the humerus and shoulder capsule in the same 16 (100%) of 16 shoulders. The AN gave branches ascending circumferentially from the quadrangular space to the posterolateral humerus, deep to the deltoid, and inserting at the inferior portion of the posterior joint capsule. In 4 previously dissected and 17 distinct shoulders, intact LPNs could be identified in 14 (67%) of 21 specimens. Of these, 12 (86%) of 14 had articular branches innervating the anterior shoulder joint, and 14 (100%) of 14 LPN articular branches were adjacent to acromial branches of the thoracoacromial blood vessels over the superior aspect of the coracoid process. Conclusions Articular branches from the SN, AN, and LPN were identified. Articular branches of the SN and AN insert into the capsule overlying the glenohumeral joint posteriorly. Articular branches of the LPN exist and innervate a portion of the anterior shoulder joint.

Maintaining Opioid Prescription for Chronic Back Pain: Pro Versus Con

A 28-year-old single man presents to your clinic for a new patient evaluation. He has had low back pain for 5 years after a motor vehicle collision. The diagnosis was diskogenic low back pain that was identified by a combination of magnetic resonance imaging and provocation diskography. A microdiskectomy procedure performed 1 year after the collision was not effective in reducing his pain. He eventually was referred to a pain management provider, who supported the ongoing use of hydrocodone/acetaminophen 10 mg/325 mg, 4 per day. For the past 3 years, the patient’s primary care provider has been prescribing this medication, but this provider will be retiring before the patient’s next monthly prescription is due, and no one in that medical clinic is willing to take over his care. The patient states that the medication allows him to be more functional, which he describes as walking 2 miles on most days, with an average pain level of 3 on a 0-10 numeric rating scale. He states that he occasionally runs out of medication ahead of his next prescription and when he does, his pain increases to 7 of 10. The original motor vehicle claim has since been legally settled, and his income is now primarily from Social Security Disability Insurance due to chronic low back pain, which he was awarded on an appeal. He was a laborer before the motor vehicle collision, and he has no specific return-to-work goals. He attempted to attend classes at a community college but decided that he could not sit comfortably enough to concentrate. He owns a car that “sometimes runs” and will take short road trips to shoot photographs. He does not stop taking opioids when driving. At the new patient evaluation, he denies other medical problems and denies taking any other prescription or “street” medication. He takes generic ibuprofen about 50% of the days, usually 600-800 mg per day. His alcohol consumption is reported as a “6 pack per week.” He responds that he once obtained “professional counseling” for his pain, but that was “not effective.” His previous provider “trusted” him enough that he did not have to sign a pain contract. He was also unaware of the process of urine testing. He is now requesting that you continue the opioid prescription, or he fears that he will have to turn to illegal sources. What is the next most reasonable action for you to take? Dr Maxim Eckmann will argue for continuing the patient’s opioid prescription, and Dr Ameet Nagpal will argue against continuing opioids.

Brachial Plexus Chemical Neurolysis with Ethanol for Cancer Pain

Chemical neurolytic nerve blocks have been successfully used to treat a variety of cancer-related pain. However, the literature has been sparse regarding neurolysis of the brachial plexus for cancer pain. We present a unique case report of a successful chemical neurolysis of the brachial plexus with dehydrated ethanol for a patient suffering from metastatic mammary carcinoma with tumor invasion of the right brachial plexus.

Evidence-based pain medicine for primary care physicians

ABSTRACT The last several decades have seen a marked increase in both the recognition and treatment of chronic pain. Unfortunately, patients frequently misunderstand both the nature of pain and the best practices for its treatment. Because primary care physicians treat the majority of chronic pain, they are ideally situated to provide evidence-based pain care. The majority of the medical evidence supports a biopsychosocial model of pain that integrates physical, emotional, social, and cultural variables. The goal of this primer is to assist primary care physicians in their understanding of pain, evaluation of the chronic pain patient, and ability to direct evidence-based care. This article will discuss the role of physical rehabilitation, pain psychology, pharmacotherapy, and procedural interventions in the treatment of chronic pain. Given the current epidemic of drug-related deaths, particular emphasis is placed on the alternatives to opioid therapy. Unfortunately, death is not the only significant complication from opioid therapy, and this article discusses many of the most common side effects. This article provides general guidelines on the most appropriate utilization of opioids with emphasis on the recent Centers for Disease Control and Prevention guidelines, risk stratification, and patient monitoring. Finally, the article concludes with the critical role that a pain medicine specialist can play in the management of patients with chronic pain.

Poster 123: Cadaveric Study of the Articular Branches of the Shoulder Joint

tasks. Participants with SCI had similar activity counts within tasks compared to those without SCI except for walking/wheeling. Agreement was high between monitors across tasks (ICCs 1⁄4 .78 .92). Conclusions: Both monitors demonstrated good construct validity for measuring physical activity across activities and high agreement. Either monitor may be appropriate to examine physical activity patterns in individuals with SCI. Level of Evidence: Level II

A Unique Case for Spinal Cord Stimulation: Successful Treatment of Small Fiber Neuropathy Pain Using Multiple Spinal Cord Stimulators

Spinal cord stimulators have commonly been used to treat multiple pain conditions. This case report represents a unique case of using multiple spinal cord stimulators for widespread small fiber neuropathy pain. This case report concerns patient JJ who first presented with generalized neuropathic pain. His pain was an intermittent burning, stinging quality that originally focused in both of his feet and progressed to include his legs and arms and eventually involved his entire body. The pain would last moments to hours at least daily. He reported a poor quality of life. He was diagnosed with small fiber neuropathy with anhydrosis, suggestive of idiopathic erythromelalgia. He had a spinal cord stimulator trial involving both cervical and lower thoracic percutaneous leads. After two spinal cord stimulators were implanted, the patient began to report an improvement in pain. The patient continues to report excellent pain relief. The patient uses the stimulator intermittently as needed, in an abortive fashion for pain flares. The patient is very pleased and has increased his activity. He now attends graduate school full time. This case report hopes to illustrate a unique use of multiple spinal cord stimulators in treating widespread neuropathic pain caused by small fiber neuropathy.

A Novel Use of Regional Anesthesia for Spastic Hemiplegia Evaluation and Treatment: A Case Report

Spastic hemiplegia is a common sequela of stroke. Spasticity that is not optimally reduced with systemic therapy is often treated with intramuscular botulinum toxin injections. Spastic tone can increase the difficulty of appropriately positioning the patient for botulinum toxin injections, lengthen procedure duration, and increase periprocedural pain. Our patient, a 53‐year‐old woman, was unable to be adequately positioned to receive botulinum toxin injections to her left upper extremity because of challenging flexion synergy posturing and related positional pain. A left interscalene brachial plexus local anesthetic block administered under ultrasound guidance was used to produce both temporary dense muscle relaxation and profound anesthesia, facilitating successful and comfortable botulinum toxin injections in this patient.