Lamer, Tim J.

Background: Any spine structure that is innervated by afferent nociceptive nerve fibers is a potential pain generator. In the lumbar spine, the most studied pain generators include: sacroiliac joints, the zygapophysial joints, the intervertebral discs, myofascial structures. Anomalous lumbosacral articulations, the spinous processes, and lumbar spine osteophytes are less commonly reported. Objective: To describe the diagnostic and therapeutic features of “kissing spine” disease or Baastrup’s Sign with particular attention to MRI findings and fluoroscopicallyguided injection therapy. Design: A series of 3 patients with axial low back pain presented with exam findings and MRI changes suggestive of pain emanating from adjacent spinous processes that appeared to be in direct contact or very closely opposed. This has been described in the literature as “kissing spine” disease or Baastrup’s sign. Fluoroscopically-guided injections were performed and the responses were studied. Results: The 3 patients had MRI findings consisting of inflammation and/or edema in the spinous processes and surrounding soft tissues. Fluoroscopically-guided injections provided pain relief in all 3 patients. One patient with recurrent pain eventually underwent successful surgical resection of the involved spinous processes. Conclusion: Painful adjacent and closely opposed spinous processes can be a source of axial low back pain. We have described MRI features and the responses to fluoroscopically-guided injections in 3 patients with this condition. Key words: Baastrup’s, kissing spine, spine injection

Introduction Interventional pain procedures have increased in complexity, often requiring longer radiation exposure times and subsequently higher doses. The practicing physician requires an in-depth knowledge and evidence-based knowledge of radiation safety to limit the health risks to themselves, patients and healthcare staff. The objective of this study was to examine current radiation safety practices and knowledge among interventional pain physicians and compare them to evidence-based recommendations. Materials and methods A 49-question survey was developed based on an extensive review of national and international guidelines on radiation safety. The survey was web-based and distributed through the following professional organizations: Association of Pain Program Directors, American Academy of Pain Medicine, American Society of Regional Anesthesia and Pain Medicine, European Society of Regional Anesthesia and Pain Therapy, International Neuromodulation Society, and North American Neuromodulation Society. Responses to radiation safety practices and knowledge questions were evaluated and compared with evidence-based recommendations. An exploratory data analysis examined associations with radiation safety training/education, geographical location, practice type, self-perceived understanding, and fellowship experience. Results Of 708 responding physicians, 93% reported concern over the health effects of radiation, while only 63% had ever received radiation safety training/education. Overall, ≥80% physician compliance with evidence-based radiation safety practice recommendations was demonstrated for only 2/15 survey questions. Physician knowledge of radiation safety principles was low, with 0/10 survey questions having correct response rates ≥80%. Conclusion We have identified deficiencies in the implementation of evidence-based practices and knowledge gaps in radiation safety. Further education and training are warranted for both fellowship training and postgraduate medical practice. The substantial gaps identified should be addressed to better protect physicians, staff and patients from unnecessary exposure to ionizing radiation during interventional pain procedures.

Abstract Erythromelalgia is a rare neurovascular disorder characterized by erythema, warmth, and episodic burning pain, often felt in the face, hands, and feet. Symptoms are typically worse with heat, exercise, stress, and during the overnight hours. Management often requires a multidisciplinary approach, including pain trigger avoidance, cool water baths, and topical and oral neuropathic medications. The use of spinal cord stimulation has been described in multiple case reports with success reported out to 24 months. To our knowledge, the use of dorsal root ganglion (DRG) stimulation for erythromelalgia‐related pain has not been described. Herein, we present a case of erythromelalgia‐related pain at the bilateral plantar surfaces of the feet, which was treated successfully with bilateral sacral S1 nerve root DRG stimulation.

Abstract Purpose Peripheral nerve stimulation (PNS) is a rapidly expanding field within neuromodulation; however, there is limited data on therapeutic efficacy. This study describes the indications and clinical outcomes for patients undergoing PNS for chronic pain states. Patients and Methods This is a retrospective case series of adults undergoing PNS implantation from 2004 to 2017 at an academic medical center. The primary outcomes were changes in numeric rating scale (NRS) pain scores, opioid utilization in oral morphine milligram equivalent (MME), and self‐reported patient functioning at 6 months postoperatively. Infectious and device‐related complications were also assessed. Results A total of 72 patients underwent PNS implantation, including 59 patients that received a preceding PNS trial (59/78; 76% progression rate) and 13 that did not receive a PNS trial. The most common indication for stimulation was occipital neuralgia (47%) followed by lower‐extremity neuropathies (17%). PNS implantation was associated with 6‐month reductions in pain scores (7 [6, 8] baseline vs. 4 [2, 5] 6 months; P < 0.001) and opioid utilization (eg, median 60 [31, 104] vs. 18 [0, 52] MME among those with baseline opioid use; P < 0.001). Median functional improvement was 73% (50%, 88%). Seven patients (10%) suffered a postoperative surgical site infection at a median of 50 (30, 124) days, of which five devices were removed. Conclusion Peripheral nerve stimulation was associated with reduced pain scores, lower opioid utilization, and improved patient function at 6 months. These data support PNS as a potentially effective nonopioid analgesic modality in chronic pain, though prospective multicenter evaluation is warranted to evaluate longer‐term outcomes.

AbstractObjectiveTo conduct a systematic literature review of dorsal root ganglion (DRG) stimulation for pain.DesignGrade the evidence for DRG stimulation.MethodsAn international, interdisciplinary work group conducted a literature search for DRG stimulation. Abstracts were reviewed to select studies for grading. General inclusion criteria were prospective trials (randomized controlled trials and observational studies) that were not part of a larger or previously reported group. Excluded studies were retrospective, too small, or existed only as abstracts. Studies were graded using the modified Interventional Pain Management Techniques–Quality Appraisal of Reliability and Risk of Bias Assessment, the Cochrane Collaborations Risk of Bias assessment, and the US Preventative Services Task Force level-of-evidence criteria.ResultsDRG stimulation has Level II evidence (moderate) based upon one high-quality pivotal randomized controlled trial and two lower-quality studies.ConclusionsModerate-level evidence supports DRG stimulation for treating chronic focal neuropathic pain and complex regional pain syndrome.

AbstractObjectiveTo conduct a systematic literature review of peripheral nerve stimulation (PNS) for pain.DesignGrade the evidence for PNS.MethodsAn international interdisciplinary work group conducted a literature search for PNS. Abstracts were reviewed to select studies for grading. Inclusion/exclusion criteria included prospective randomized controlled trials (RCTs) with meaningful clinical outcomes that were not part of a larger or previously reported group. Excluded studies were retrospective, had less than two months of follow-up, or existed only as abstracts. Full studies were graded by two independent reviewers using the modified Interventional Pain Management Techniques–Quality Appraisal of Reliability and Risk of Bias Assessment, the Cochrane Collaborations Risk of Bias assessment, and the US Preventative Services Task Force level-of-evidence criteria.ResultsPeripheral nerve stimulation was studied in 14 RCTs for a variety of painful conditions (headache, shoulder, pelvic, back, extremity, and trunk pain). Moderate to strong evidence supported the use of PNS to treat pain.ConclusionPeripheral nerve stimulation has moderate/strong evidence. Additional prospective trials could further refine appropriate populations and pain diagnoses.

AbstractObjectiveTo conduct a systematic literature review of spinal cord stimulation (SCS) for pain.DesignGrade the evidence for SCS.MethodsAn international, interdisciplinary work group conducted literature searches, reviewed abstracts, and selected studies for grading. Inclusion/exclusion criteria included randomized controlled trials (RCTs) of patients with intractable pain of greater than one year’s duration. Full studies were graded by two independent reviewers. Excluded studies were retrospective, had small numbers of subjects, or existed only as abstracts. Studies were graded using the modified Interventional Pain Management Techniques–Quality Appraisal of Reliability and Risk of Bias Assessment, the Cochrane Collaborations Risk of Bias assessment, and the US Preventative Services Task Force level-of-evidence criteria.ResultsSCS has Level 1 evidence (strong) for axial back/lumbar radiculopathy or neuralgia (five high-quality RCTs) and complex regional pain syndrome (one high-quality RCT).ConclusionsHigh-level evidence supports SCS for treating chronic pain and complex regional pain syndrome. For patients with failed back surgery syndrome, SCS was more effective than reoperation or medical management. New stimulation waveforms and frequencies may provide a greater likelihood of pain relief compared with conventional SCS for patients with axial back pain, with or without radicular pain.