Peripheral Nerve Stimulation in Pain Management: A Systematic Review.

BACKGROUND: Peripheral nerve stimulation (PNS) has been increasingly used to manage acute and chronic pain. However, the level of clinical evidence to support its use is not clear. OBJECTIVES: To assess the clinical evidence of PNS in the treatment of acute or chronic pain. STUDY DESIGN: A systematic review of the efficacy and safety of PNS in managing acute or chronic pain. METHODS: Data sources were PubMed, Cochrane Library, Scopus, CINAHL Plus, Google Scholar, and reference lists. The literature search was performed up to December 2019. Study selection included randomized trials, observational studies, and case reports of PNS in acute or chronic pain. Data extraction and methodological quality assessment were performed utilizing Cochrane review methodologic quality assessment and Interventional Pain Management Techniques-Quality Appraisal of Reliability and Risk of Bias Assessment (IPM-QRB) and Interventional Pain Management Techniques-Quality Appraisal of Reliability and Risk of Bias Assessment for Nonrandomized Studies (IPM-QRBNR). The evidence was summarized utilizing principles of best evidence synthesis on a scale of 1 to 5. Data syntheses: 227 studies met inclusion criteria and were included in qualitative synthesis. RESULTS: Evidence synthesis based on randomized controlled trials (RCTs) and observational studies showed Level I and II evidence of PNS in chronic migraine headache; Level II evidence in cluster headache, postamputation pain, chronic pelvic pain, chronic low back and lower extremity pain; and Level IV evidence in peripheral neuropathic pain, and postsurgical pain. Peripheral field stimulation has Level II evidence in chronic low back pain, and Level IV evidence in cranial pain. LIMITATIONS: Lack of high-quality RCTs. Meta-analysis was not possible due to wide variations in experimental design, research protocol, and heterogeneity of study population. CONCLUSIONS: The findings of this systematic review suggest that PNS may be effective in managing chronic headaches, postamputation pain, chronic pelvic pain, and chronic low back and lower extremity pain, with variable levels of evidence in favor of this technique.

Comparison of post-operative pain scores and opioid use between kyphoplasty and radiofrequency ablation (RFA) systems combined with cement augmentation.

OBJECTIVE: This retrospective chart review study aims to compare demographic information, post-operative pain scores, and opioid use following treatment with kyphoplasty alone, OsteoCool™ (Medtronic) system, and SpineSTAR ® (Merit Medicine). MATERIALS AND METHODS: Following institutional review board approval, retrospective chart review of 64 patients was examined between January 2011 and December 2017. Inclusion criteria for this study comprised patients greater than 18 years old having metastatic vertebral compression fracture involving the thoracolumbar spine. Exclusion criteria consisted of non-pathologic osteoporotic compression fractures, metastasis in cervical spine, or previous radiofrequency ablation (RFA) treatment. Age at intervention, gender, previous treatment, and nursing recorded VAS score from 0 to 10, with zero representing no pain and 10 representing worst pain were compared. Pain scores documented immediately pre- and post-operatively, as well as 7-14 days post-operatively were targeted for analysis. Post-procedure opioid intake during the first month following surgery was also assessed. RESULTS: A total of 63 patients were included in this retrospective analysis. The demographic characteristics between the treatment arms were similar. Difference of square means analysis showed no statistical difference in pain scores at each time interval between the two RFA systems, or was there a statistical difference in pain scores when each RFA system was compared independently to kyphoplasty alone. Chi-squared analysis showed no statistical difference in opioid use between the treatment arms 1 month post-operatively. DISCUSSION: To our knowledge, this is the first study that evaluates post-operative pain scores between the two novel RFA systems and kyphoplasty alone. Each system results in improved pain scores post-operatively; however, no additional benefit was seen from the addition of RFA.

Perioperative Pharmacologic Considerations in Obesity.

Obesity has increased in incidence worldwide. Along with the increased number of obese patients, comorbid conditions are also more prevalent in this population. Obesity leads to changes in the physiology of patients along with an altered response to pharmacologic therapy. Vigilant perioperative physicians must be aware of the unique characteristics of administered agents in order to appropriately provide anesthetic care for obese patients. Because of the variability in tissue content in obese patients and changes in pharmacokinetic modeling, a one-size-fits-all approach is not justified and a more sophisticated and prudent approach is indicated.

Pharmacologic Considerations of Anesthetic Agents in Geriatric Patients.

Aging is a natural process of declining organ function and reserve. Census data show that the geriatric population is expected to grow to nearly 30%. More than half of geriatric patients have 1 or more surgical procedures in their lifetimes. Moreover, this is the population at greatest risk of morbidity and mortality with any given complication. There is remarkable variability in health across the age spectrum, from fit to frail and compromised. This variability requires a unique approach to anesthetic delivery and drug dosing on an individual basis to avoid complications such as postoperative cognitive dysfunction and delirium.

Digital Subtraction Angiography Use During Epidural Steroid Injections Does Not Reliably Distinguish Artery from Vein.

BACKGROUND: Epidural steroid injections (ESIs) are among the most common procedures performed in an interventional pain management practice. It is well known that tragic complications may arise from ESIs, most commonly those performed using a transforaminal approach. Digital subtraction angiography (DSA) has been hailed as a fluoroscopic technique that can be used to detect arterial placement of the injection needle, and therefore as a safety measure that can decrease the incidence of catastrophic sequelae of these procedures. OBJECTIVE: The objective of this article was to review existing scientific pain literature to determine if DSA can distinguish arterial vs. venous uptake. STUDY DESIGN: Narrative review. METHODS: The current narrative review of DSA in interventional spine was completed with a PUBMED search using the key words: digital subtraction angiography, epidural, fluoroscopy, intravascular injection, paraplegia, and quadriplegia in accordance with Preferred Reporting Items for Systematic Reviews and Meta- Analyses (PRISMA) guidelines. RESULTS: After identification of duplicate articles, 383 articles were screened by title, abstract, and/or full article review. Ten of these articles were deemed appropriate, after applying inclusion and exclusion criteria, as they specifically looked at the use of digital subtraction angiography in interventional spine epidural injections. This included 4 case reports, 3 prospective studies, one retrospective analysis, one prospective cohort study, and one meta-analysis. All of the available studies claiming that DSA was capable of detecting vascular spread are likely accurate, but no significant detection of specifically arterial spread has been reported. The known catastrophic complications related to ESIs are purported to be due to arterial injection of insoluble steroids or local anesthetic and detection of arterial spread of contrast during fluoroscopy would be of obvious benefit to the interventionalist. LIMITATIONS: Small study size, non-randomized studies between DSA and real time fluoroscopy. CONCLUSION: Existing studies do not support that DSA can predict arterial spread. In fact, DSA exposes the practitioner and the patient to higher levels of radiation without objective evidence of any safety parameters. KEY WORDS: Digital subtraction angiography, real-time fluoroscopy, transforaminal epidural injection, particulate steroids, cervical radicular artery, lumbar radicular artery, spinal cord injury.

Perioperative Pain Control in the Ambulatory Setting.

Across the USA and various parts of the world, ambulatory surgery centers have transitioned to accepting patients with advanced ASA statuses, leading to a larger volume and higher complexity of surgeries performed, while still urging for same-day patient discharges. Inadequate postoperative pain management and opioid analgesia side effects, such as sedation, respiratory depression, and postoperative nausea and vomiting, are the most common complications and most common reasons for readmission after ambulatory surgery. The trend to limiting these complications and achieve a more rapid patient discharge currently emphasizes a multifactorial, balanced analgesia strategy. This article reviews the multimodal approach by detailing the important aspects of specific regional nerve blocks, nerve blockade with catheter techniques, acetaminophen, non-selective NSAIDs, Cox-2 inhibitors, membrane stabilizers, and corticosteroids. Pain management in the ambulatory surgery patient will thus be optimized with a thorough preoperative evaluation, recognizing intraoperative events, and implementing multiple analgesic modalities.

An International Survey to Understand Infection Control Practices for Spinal Cord Stimulation.

OBJECTIVES: Surgical site infections (SSIs) are associated with significant healthcare costs and morbidity. Limited research exists specific to the prevention of spinal cord stimulation (SCS) SSIs. The objectives of this international survey were to examine current infection control practices for SCS trials and implants and to compare reported responses with evidence-based recommendations. MATERIALS AND METHODS: A 33-question survey was developed based on an extensive literature review for infection control policies. The survey was hosted on the Internet. Dispersion of the survey occurred through professional associations and device manufacturers. Responses to 15 questions directly related to defined CDC, NICE, and SCIP evidence-based infection control practice recommendations were classified as either compliant or noncompliant. The survey was open for 20 days. Responses also were grouped and analyzed based on geographic location, practice location, and procedural volumes. RESULTS: Five hundred six physicians responded to the survey. Compliance rates for CDC, NICE, SCIP infection control practice recommendations were low with only four of the 15 questions having compliance rates ≥80%. Areas associated with high levels of noncompliance included weight-based antibiotic dosing, hair removal strategies, double gloving, surgical dressing, skin antiseptic agent selection, and postoperative continuation of antibiotics. Geographic and practice type variations existed for particular infection control practices. Procedural volume influenced operative implant times with low physician procedural volumes associated with extended operative times. CONCLUSIONS: The survey provided significant insight into current practices and will assist in the development of specific SCS infection control policies. Based on the survey, further education is warranted on infection control strategies for physicians performing spinal cord stimulator trials and implants.

Efficacy of Epidural Injections in Managing Chronic Spinal Pain: A Best Evidence Synthesis.

BACKGROUND: Epidural injections have been used since 1901 in managing low back pain and sciatica. Spinal pain, disability, health, and economic impact continue to increase, despite numerous modalities of interventions available in managing chronic spinal pain. Thus far, systematic reviews performed to assess the efficacy of epidural injections in managing chronic spinal pain have yielded conflicting results. OBJECTIVE: To evaluate and update the clinical utility of the efficacy of epidural injections in managing chronic spinal pain. STUDY DESIGN: A systematic review of randomized controlled trials of epidural injections in managing chronic spinal pain. METHODS: In this systematic review, randomized trials with a placebo control or an active-control design were included. The outcome measures were pain relief and functional status improvement. The quality of each individual article was assessed by Cochrane review criteria, as well as the Interventional Pain Management Techniques-Quality Appraisal of Reliability and Risk of Bias Assessment (IPM-QRB). Best evidence synthesis was conducted based on the qualitative level of evidence (Level I to V). Data sources included relevant literature identified through searches of PubMed for a period starting in 1966 through August 2015; Cochrane reviews; and manual searches of the bibliographies of known primary and review articles. RESULTS: A total of 52 trials met inclusion criteria. Meta-analysis was not feasible. The evidence in managing lumbar disc herniation or radiculitis is Level II for long-term improvement either with caudal, interlaminar, or transforaminal epidural injections with no significant difference among the approaches. The evidence is Level II for long-term management of cervical disc herniation with interlaminar epidural injections. The evidence is Level II to III in managing thoracic disc herniation with an interlaminar approach. The evidence is Level II for caudal and lumbar interlaminar epidural injections with Level III evidence for lumbar transforaminal epidural injections for lumbar spinal stenosis. The evidence is Level III for cervical spinal stenosis management with an interlaminar approach. The evidence is Level II for axial or discogenic pain without facet arthropathy or disc herniation treated with caudal or lumbar interlaminar injections in the lumbar region; whereas it is Level III in the cervical region treated with cervical interlaminar epidural injections. The evidence for post lumbar surgery syndrome is Level II with caudal epidural injections and for post cervical surgery syndrome it is Level III with cervical interlaminar epidural injections. LIMITATIONS: Even though this is a large systematic review with inclusion of a large number of randomized controlled trials, the paucity of high quality randomized trials literature continues to confound the evidence. CONCLUSION: This systematic review, with an assessment of the quality of manuscripts and outcome parameters, shows the efficacy of epidural injections in managing a multitude of chronic spinal conditions.

Reprogramming of in situ spinal cord stimulator for covering newly developed postthoracotomy pain.

The objective of this case report is to describe the use of in situ spinal cord stimulator (SCS) for postthoracotomy pain syndrome (PTPS). We report a 39-year-old woman with complex regional pain syndrome type I of the left lower extremity. The patient's pain was relieved by a SCS for 1 month before the patient developed slipping rib syndrome at her T12 rib from an unrelated trauma. After failed conservative treatments and undergoing a thoracotomy procedure, the patient developed PTPS. Conservative management with medications and intercostal nerve blocks provided short-term relief. An already implanted single Octrode with Eon Mini generator (St Jude Neuromodulator, Plano, TX) at the T7 level was reprogrammed in attempt to recruit peripheral fibers to target the patient's additional areas of chest discomfort. This adjustment improved the pain at the left lateral rib area as well as her left leg. The patient was followed for 1 year, and her quality of life improved since her initial presenting symptoms. The use of the SCS in this patient provided significant lasting pain relief for both complex regional pain syndrome and PTPS. We believe that the use of SCS should be considered as a treatment option for patients with PTPS to avoid side effects associated with medications and to provide long-term pain relief.

Celiac plexus block in the management of chronic abdominal pain.

Chronic abdominal pain is a devastating problem for patients and providers, due to the difficulty of effectively treating the entity. Both benign and malignant conditions can lead to chronic abdominal pain. Precision in diagnosis is required before effective treatment can be instituted. Celiac Plexus Block is an interventional technique utilized for diagnostic and therapeutic purposes in the treatment of abdominovisceral pain. The richly innervated plexus provides sensory input about pathologic processes in the liver, pancreas, spleen, omentum, alimentary tract to the mid-transverse colon, adrenal glands, and kidney. Chronic pancreatitis and chronic pain from pancreatic cancer have been treated with celiac plexus block to theoretically decrease the side effects of opioid medications and to enhance analgesia from medications. Historically, the block was performed by palpation and identification of bony and soft tissue anatomy; currently, various imaging modalities are at the disposal of the interventionalist for the treatment of pain. Fluoroscopy, computed tomography (CT) guidance and endoscopic ultrasound assistance may be utilized to aid the practitioner in performing the blockade of the celiac plexus. The choice of radiographic technology depends on the specialty of the interventionalist, with gastroenterologists favoring endoscopic ultrasound and interventional pain physicians and radiologists preferring CT guidance. A review is presented describing the indications, technical aspects, and agents utilized to block the celiac plexus in patients suffering from chronic abdominal pain.

Concordant pressure paresthesia during interlaminar lumbar epidural steroid injections correlates with pain relief in patients with unilateral radicular pain.

BACKGROUND: Transforaminal and interlaminar epidural steroid injections are commonly used interventional pain management procedures in the treatment of radicular low back pain. Even though several studies have shown that transforaminal injections provide enhanced short-term outcomes in patients with radicular and low back pain, they have also been associated with a higher incidence of unintentional intravascular injection and often dire consequences than have interlaminar injections. OBJECTIVES: We compared 2 different approaches, midline and lateral parasagittal, of lumbar interlaminar epidural steroid injection (LESI) in patients with unilateral lumbosacral radiculopathic pain. We also tested the role of concordant pressure paresthesia occurring during LESI as a prognostic factor in determining the efficacy of LESI. STUDY DESIGN: Prospective, randomized, blinded study. SETTING: Pain management center, part of a teaching-community hospital in a major metropolitan US city. METHODS: After Institutional Review Board approval, 106 patients undergoing LESI for radicular low back pain were randomly assigned to one of 2 groups (53 patients each) based on approach: midline interlaminar (MIL) and lateral parasagittal interlaminar (PIL). Patients were asked to grade any pressure paresthesia as occurring ipsilaterally or contralaterally to their "usual and customary pain," or in a distribution atypical of their daily pain. Other variables such as: the Oswestry Disability Index questionnaire, pain scores at rest and during movement, use of pain medications, etc. were recorded 20 minutes before the procedure, and on days 1, 7, 14, 21, 28, 60, 120, 180 and 365 after the injection. RESULTS: Results of this study showed statistically and clinically significant pain relief in patients undergoing LESI by both the MIL and PIL approaches. Patients receiving LESI using the lateral parasagittal approach had statistically and clinically longer pain relief then patients receiving LESI via a midline approach. They also had slightly better quality of life scores and improvement in everyday functionality; they also used less pain medications than patients receiving LESI using a midline approach. Furthermore, patients in the PIL group described significantly higher rates of concordant moderate-to-severe pressure paresthesia in the distributions of their "usual and customary pain" compared to the MIL group. In addition, patients who had concordant pressure paresthesia and no discordant pressure paresthesia (i.e., "opposite side or atypical") during interventional treatment had better and longer pain relief after LESI. Two patients from each group required discectomy surgery in the one-year observation period. LIMITATIONS: The major limitation of this study is that we did not include a transforaminal epidural steroid injection group, since that is one of the approaches still commonly used in contemporary pain practices for the treatment of low back pain with unilateral radicular pain. CONCLUSIONS: This study showed that the lateral parasagittal interlaminar approach was more effective than the midline interlaminar approach in targeting low back pain with unilateral radicular pain secondary to degenerative lumbar disc disease. It also showed that pressure paresthesia occurring ipsilaterally during an LESI correlates with pain relief and may therefore be used as a prognostic factor.

Managing and treating headache of cervicogenic origin.

CGH is a common entity that has been assessed historically in various medical disciplines. Currently, CGH is a controversial topic whose existence has supporters and naysayers. The difficulty evaluating CGH is caused by a lack of objective findings on imaging and biologic tests. Patients present with pain but often with a lack of hard, concrete physical findings. Other clinical diagnoses may confound the clinical presentation of patients. The concomitant presence of ON and migraine headaches has been noted in the literature. Positive analgesia after interventional techniques remains the major way to consider the diagnosis in potential patients with headaches. Although the IHS has acknowledged CGH as a secondary headache in its diagnostic schema, more research, specifically randomized double-blinded evaluations of patients with CGH, are required. These data would be deemed as objective gold-standard evidence to lead us from controversy to collaborative agreement regarding the fate of CGH. What is certain regarding CGH is that a cooperative effort should be considered in the treatment of the patients between evaluating physicians, interventional pain physicians, surgeons, and physical therapy providers. This multidisciplinary effort can lead to the effective management of CGH.

Tripolar spinal cord stimulation for the treatment of abdominal pain associated with irritable bowel syndrome.

OBJECTIVES: The objective of this case report is to describe the use of transverse tripolar dorsal column stimulation in a patient with a history of irritable bowel syndrome (IBS) associated with abdominal pain resistant to conservative treatments. METHOD: We report a 36-year-old man who presented to the pain clinic with an eight-year history of IBS (constipation predominant with occasional diarrheal episodes), with "crampy and sharp" abdominal pain. He also had nonradicular thoracic spine pain due to thoracic scoliosis. Both pains were affecting his ability to function as an attorney. Prior conservative therapy, including psychologic treatment, antidepressants, and opioids, was without any benefits. RESULTS: The use of a spinal cord stimulator (SCS) was discussed with the patient. The procedure was performed after Institutional Review Board approval. A tripolar SCS was implanted at the T8 level using one-eight contact and two-four contact percutaneous leads based on paresthesia reproduction of patient's areas of discomfort. This tripolar spinal cord stimulation provided relief of abdominal and thoracic pain, and better management of gastrointestinal symptoms. The patient was followed-up for one year, and his quality of life also was improved via the IBS-Severity Scoring System quality of life tool. CONCLUSIONS: The use of the tripolar SCS in this patient provided relief of abdominal and thoracic spine pain, regulated bowel habits, and improved the patient's quality of life. We believe that the use of SCS should be considered as a treatment option in patients with IBS when all conservative treatments failed.

Microdiscectomy: spinal anesthesia offers optimal results in general patient population.

Spinal anesthesia provides a safe and highly satisfactory alternative to general anesthesia in patients undergoing limited lumbar surgery. Nevertheless, it is not commonly used for spinal surgery, and in some centers it is not even considered as an option for spinal procedures. This study presents the current anesthetic technique for patients undergoing microdiscectomy and compares the peri- and postoperative outcomes in 76 patients drawn from a case-controlled study group. Patients underwent microdiscectomy for herniated nucleus pulposus under spinal (43 patients) or general anesthesia (33 patients). Patients ranged from 18 to 40 years, and all were anesthesia class 1. Surgical and anesthesia times were longer for the general anesthetic group, as was total anesthetic time. Urinary retention was more common in the general anesthesia group (p = .035). Postanesthetic care unit admission times were significantly shorter among general anesthetic patients compared with spinal anesthetic patients (p < .001). Spinal anesthesia patients required less pain medication and experienced less nausea and emesis. Even among young, medically fit patients, spinal anesthesia provided specific advantages over general anesthesia, including decreased anesthesia time, decreased nausea and antiemetic requirements, reduced analgesic requirements, and a trend toward lower complication rates and shorter hospital stay. Both surgeon and patient satisfaction with this anesthetic approach is high.

Comparison of spinal and general anesthesia in lumbar laminectomy surgery: a case-controlled analysis of 400 patients.

OBJECT: Despite a history of safety and efficacy, spinal anesthesia is rarely used in lumbar surgery. Application of regional anesthetics is widely preferred for lower-extremity surgery, but general anesthesia is used almost exclusively in spine surgery, despite evidence that spinal anesthesia is as safe and may offer some advantages. METHODS: In this case-controlled study the authors analyzed outcomes obtained in 400 patients in whom either spinal anesthesia or general anesthesia was induced to perform a lumbar decompression. Patients were matched for anesthesia-related class, preoperative diagnosis, surgical procedure, and perioperative protocols. All aspects of surgery, recovery, postanesthesia care, and pain management were uniform irrespective of the anesthetic type. Case complexity was equivalent. An independent observer performed analysis of the data. Data from the intraoperative period through hospital discharge were collected and compared. Two hundred consecutive patients meeting inclusion criteria were included in each group. Patients were treated for either lumbar stenosis or herniated nucleus pulposus. Demographically, both groups were well matched. Anesthetic and operative times were longer for patients receiving a general anesthetic (p < 0.05), in whom more nausea and greater requirements for antiemetics and pain medication were also present during recovery (p < 0.05). Overall complication rates and, specifically, the incidences of urinary retention were significantly lower in spinal anesthesia--induced patients (p < 0.05). There were no neural injuries in either group, and the incidence of spinal headache was lower in patients receiving a spinal anesthetic (1.5% compared with 3%). CONCLUSIONS: Spinal anesthesia was as safe and effective as general anethesia for patients undergoing lumbar laminectomy. Potential advantages of spinal anesthsia include a shorter anesthesia duration, decreased nausea, antiemetic and analgesic requirements, and fewer complications. Successful surgery can be performed using either anesthesia type.

Conversion disorder mimicking Dejerine-Roussy syndrome (thalamic stroke) after spinal cord stimulation.

OBJECTIVE: Dejerine-Roussy syndrome is a complex of various signs and symptoms in patients suffering from central thalamic pain, usually secondary to a vascular etiology. We describe a patient presenting with the potentially devastating signs and symptoms of thalamic stroke, at least temporally related to spinal cord stimulator implantation. The etiology of the patient's affliction was subsequently revealed to be a conversion disorder. Case report A 37-year-old woman presented for spinal cord stimulation as treatment of her brachial plexopathy after failure of conservative therapy. Before implantation, she underwent a clinical interview with a psychologist and psychometric testing. No psychological pathology was detected. Trial and permanent implantation of the cervical stimulator lead and pulse generator were uneventful. Eleven days after receiving the permanent implant, the patient experienced right-sided hemicorporal numbness and burning dysesthesia. The patient was admitted, and a diagnosis of Dejerine-Roussy syndrome (thalamic stroke) was made. She was discharged, and her symptomatology waxed and waned over a period of weeks. The patient was subsequently admitted for psychiatric evaluation because of anxiety attacks. During her protracted admission, her psychiatrists strongly suspected a conversion disorder. The stimulator was removed, and the patient received supportive care only. Within 6 months, sensory symptoms and all motor deficits had completely resolved. CONCLUSIONS: Despite careful preoperative evaluation, latent psychosocial issues may limit the effectiveness of spinal cord stimulation. We present a case of conversion disorder masquerading as Dejerine-Roussy syndrome after spinal cord stimulation. The implications of the failure of preoperative psychological evaluation and screening to avert implantation are discussed.