Device-Related Complications Associated with Cylindrical Lead Spinal Cord Stimulator Implants: A Comprehensive Review.

PURPOSE OF REVIEW: Spinal cord stimulation (SCS) is an increasingly utilized therapy for the treatment of neuropathic pain conditions. Though minimally invasive and reversable, there are several important device-related complications that physicians should be aware of before offering this therapy to patients. The aim of this review is to synthesize recent studies in device-related SCS complications pertaining to cylindrical lead implantation and to discuss etiologies, symptoms and presentations, diagnostic evaluation, clinical implications, and treatment options. RECENT FINDINGS: Device-related complications are more common than biologic complications. Device-related complications covered in this review include lead migration, lead fracture, lead disconnection, generator failure, loss of charge, generator flipping, hardware related pain, and paresthesia intolerance. The use of SCS continues to be an effective option for neuropathic pain conditions. Consideration of complications prior to moving forward with SCS trials and implantation is a vital part of patient management and device selection. Knowledge of these complications can provide physicians and other healthcare professionals the ability to maximize patient outcomes.

Pain Scales: What Are They and What Do They Mean.

PURPOSE OF REVIEW: It is essential to have validated and reliable pain measurement tools that cover a wide range of areas and are tailored to individual patients to ensure effective pain management. The main objective of this review is to provide comprehensive information on commonly used pain scales and questionnaires, including their usefulness, intended purpose, applicability to different patient populations, and associated advantages and disadvantages. RECENT FINDINGS: Acute pain questionnaires typically focus on measuring the severity of pain and the extent of relief achieved through interventions. Chronic pain questionnaires evaluate additional aspects such as pain-related functional limitations, psychological distress, and psychological well-being. The selection of an appropriate pain scale depends on the specific assessment objectives. Additionally, each pain scale has its strengths and limitations. Understanding the differences among these pain scales is essential for selecting the most appropriate tool tailored to individual patient needs in different settings. CONCLUSION: Medical professionals encounter challenges in accurately assessing pain. Physicians must be familiar with the different pain scales and their applicability to specific patient population.

Stellate ganglion block to mitigate thalamic pain syndrome of an oncological origin.

BACKGROUND: Thalamic pain syndrome (TPS) is an enigmatic and rare condition. Thalamic pain syndrome is under the umbrella of central pain syndrome, which is classically associated with multiple sclerosis, spinal cord injury, postamputation, epilepsy, stroke, tumor, and Parkinson's disease. The mainstay treatment of TPS is polypharmacy. There is uncertainty about the intermediate options to manage medication-resistant TPS before resorting to invasive, and often expensive, intracranial therapies. Stellate ganglion block (SGB) has shown promise in reducing TPS symptoms of the upper extremity and face following a thalamic ischemic event. AIMS: Discuss the effect and potential utility of SGB on ipsilateral headache, facial, and upper extremity neuropathic pain due to thalamic malignancies. MATERIALS AND METHODS: A review of two patient records that underwent SGB for treatment of TPS of oncologic origin. RESULTS: We present two cases of the successful use of SGB for the treatment of oncologic-related TPS for patients who had failed other conservative pharmacologic measures. DISCUSSION: Chronic pain is a complex experience that often simultaneously involves psychosocial, neuropathic, and nociceptive constituents. Among advanced cancer patients, factors such as an individual's spirituality, psychological stressors, and views on their mortality add layers of intricacy in addressing their pain. While TPS has been characterized in both stroke populations and oncologic populations, the treatment of SGB for pain relief in TPS has been limited to the stroke population. Repeated SGB worked to alleviate the ipsilateral headache, facial, and upper extremity pain in these two patients. The benefits of utilization of SGB, with the possibility of pain relief, within the thalamic malignancy population cannot be understated. CONCLUSION: In summary, ultrasound-guided SGB may be considered in patients with TPS due to thalamic cancer, before pursuing more invasive intracranial surgeries to treat pain.

Buprenorphine for Chronic Pain Management: a Narrative Review.

PURPOSE OF REVIEW: The aim of this review is to educate healthcare professionals regarding buprenorphine for the use of opioid use disorder (OUD) as well as for chronic pain management. This review provides physicians and practitioners with updated information regarding the distinct characteristics and intricacies of prescribing buprenorphine. RECENT FINDINGS: Buprenorphine is approved by the US Food and Drug Administration (FDA) for acute pain, chronic pain, opioid use disorder (OUD), and opioid dependence. When compared to most other opioids, buprenorphine offers superior patient tolerability, an excellent half-life, and minimal respiratory depression. Buprenorphine does have notable side effects as well as pharmacokinetic properties that require special attention, especially if patients require future surgical interventions. Many physicians are not trained to initiate or manage patients on buprenorphine. However, buprenorphine offers a potentially safer alternative for medication management for patients who require chronic opioid therapy for pain or have OUD. This review provides updated information on buprenorphine for both chronic pain and OUD.

Peripheral Nerve Stimulation for Back Pain in Patients With Multiple Myeloma as Bridge Therapy to Radiation Treatment: A Case Series.

OBJECTIVES: Patients with spinal lesions or vertebral compression fractures from multiple myeloma often present with back pain that restricts their ability to lie flat and prevents them from undergoing cancer treatment. Temporary, percutaneous peripheral nerve stimulation (PNS) has been described for cancer pain secondary to oncologic surgery or neuropathy/radiculopathy from tumor invasion. The purpose of this case series is to show the use of PNS as an analgesic bridge therapy to treat myeloma-related back pain and allow patients to complete their course of radiation. MATERIALS AND METHODS: Temporary, percutaneous PNS was placed under fluoroscopic guidance for four patients with unremitting low back pain secondary to myelomatous spinal lesions. Before PNS, the patients had pain refractory to medical management and were unable to tolerate radiation mapping and treatment owing to low back pain while supine. Patients were followed with routine clinic visits to monitor pain and progression through cancer therapy. PNS was removed after approximately 60 days or after completion of radiation. RESULTS: This case series presents four successful cases of PNS to treat low back pain from myelomatous spinal lesions and associated vertebral compression fractures. PNS targeted the medial branch nerves to treat both nociceptive and neuropathic low back pain. All four patients successfully completed radiation therapy with PNS in place. CONCLUSIONS: PNS can effectively treat low back pain secondary to myeloma-related spinal lesions as a bridge therapy to radiation. The use of PNS is a promising option for back pain from other primary or metastatic tumors. Further research is needed into the use of PNS for cancer-related back pain.

Hypnosis As A Therapy for Chronic Lower Back Pain.

PURPOSE OF REVIEW: Chronic lower back pain is a crippling condition for the individual and a significant burden on society. It is notoriously challenging to manage despite access to invasive interventions. Understanding hypnosis as a powerful therapeutic adjunct to this condition allows holistic treatment of patients in distress. RECENT FINDINGS: In addition to classic etiologies of chronic lower back pain, hypnosis has proven to be beneficial in chronic back pain caused by pregnancy, diabetic and HIV neuropathy. Combination of hypnosis with other mind-body techniques such as olfactory stimulation, music therapy and patient education offers further promise to this treatment modality. Our review provides a run-through of the fundamental mechanisms of hypnosis in moderating chronic back pain, its quantifiable benefits, its novel areas of use and its potentials in the future based on the most recent and relevant peer-reviewed literature in order to guide clinicians to better deploy this valuable resource.

Spinal Cord Stimulation in the Treatment of Cancer Pain: A Retrospective Review.

OBJECTIVES: Spinal cord stimulation (SCS) involves electrical stimulation of the dorsal spinal cord to disrupt the transmission of ascending pain signals. SCS has been used successfully to manage a variety of chronic pain conditions, but its efficacy in the treatment of pain syndromes in patients with cancer has not been established because most studies have involved a limited number of patients. The purpose of this study was to assess the efficacy of SCS in a large group of patients with cancer. MATERIALS AND METHODS: A retrospective review was performed for all patients who had SCS trials and implants placed at Memorial Sloan Kettering Cancer Center between 2003 and 2021. Patients were divided into groups based on whether their pain could be directly attributed to cancer or its treatment (cancer dependent, n = 51) and those who had incidental pain unrelated to cancer (cancer independent, n = 22). The cancer-dependent group was further subdivided into those whose pain was directly related to primary tumor invasion or metastasis (cancer related, n = 26) and those whose pain was a result of cancer treatment such as chemotherapy or surgery (treatment related, n = 25). The primary outcomes were changes in pain scores and daily oral morphine equivalents (OMEs) before intervention to one year after implant. Secondary measures included the SCS trial success rate, change in pain scores immediately after the SCS trial, and change in pain scores immediately after the SCS implant. RESULTS: Most patients in the cancer-dependent pain group (59%) and the cancer-independent pain group (68%) had successful SCS trials and subsequently went on to have SCS implants placed. The patients with cancer-dependent pain as a whole had median reduction of 1.5 points (or 23%) on a 10-point pain score immediately after implant (p = 0.001), with the effect diminishing to a median reduction of 1 point (or 15%) by one year after implant (p = 0.027). The cancer-dependent pain groups did not have a significant reduction in daily OMEs, following implantation (p = 0.30), but the cancer-independent group did have a significant reduction (p = 0.01). CONCLUSIONS: SCS can be considered as a treatment modality for patients with cancer whose pain is not adequately controlled with medical therapy or by less invasive interventions.

Effect of a structured stretching exercise program on resolution of myofascial pain and opioid usage in "legacy pain" patients: A retrospective cohort study.

OBJECTIVE: The aim of this study was to determine whether the implementation of a structured exercise stretching routine targeted at resolving myofascial pain is effective in improving outcomes of "legacy pain" patients. DESIGN: Retrospective cohort study. SETTING: Private community-based interventional pain management practice. SUBJECTS: "Legacy pain" patients, defined as patients on opioid therapy for >1 year. METHODS: Subjects were initiated on a structured home exercise stretching routine targeted at resolving myofascial pain consisting of 14 lumbar, four thoracic, and seven cervical stretches as appropriate. Daily morphine milligram equivalent, functional status (Oswestry Disability Index), and pain level (Numeric Rating Scale) were compared pre- and post-treatment at one year. RESULTS: After 1 year, exercise techniques reduced daily morphine milligram equivalent intake on average from 76.3 to 21.0 mg (p < 0.001) with 84.4% of patients decreasing their total opioid dose (p < 0.001) and 34.4% of patients being completely weaned off of opioids (p < 0.001). Numeric Rating Scale of pain and Oswestry Disability Indices were unchanged with treatment, 7.0-6.7 (p = 0.122) and 30.4-29.3 (p = 0.181), respectively. CONCLUSIONS: The addition of a structured stretching exercise program focusing on the resolution of the myofascial pain in the treatment of "legacy pain" patients was shown to significantly reduce and often discontinue opioid use without adversely affecting pain score or functionality.

An Interventional Pain Algorithm for the Treatment of Postmastectomy Pain Syndrome: A Single-Center Retrospective Review.

OBJECTIVE: Breast cancer is the most common female malignancy worldwide. Breast surgery and adjuvant oncological therapies are often required to increase survival. Treatment-related pain may persist and evolve into postmastectomy pain syndrome (PMPS) in a significant subset of breast cancer survivors. In this retrospective investigation, we will present our experience in applying an interventional algorithmic approach to treat PMPS. DESIGN: A retrospective study. SETTING: An academic cancer hospital. SUBJECTS: Adult females with PMPS diagnosis. METHODS: We reviewed 169 records with the diagnosis of PMPS from 2015 to 2019 within our health system. Pre- and post-injection pain scores, relief duration, and medication usage changes were collected. The decision to perform each procedure was based on the anatomic location of the painful area with the corresponding peripheral sensory innervation. Decision-making flow diagrams were created to present our experience in managing PMPS beyond peripheral nerve blocks. RESULTS: Ultrasound-guided peripheral nerve block results (n=350) were analyzed. The mean baseline pain score was 7, compared with the post-treatment mean score of 3 (95% confidence interval: 3.58 to 3.98, P = 0.0001). Among the responders, the mean pain relief duration was 45 days, with a median of 84 days. Opioid medication consumption was reduced by 11% (t = 0.72, P = 0.47). CONCLUSIONS: Ultrasound-guided nerve blocks of this area could be performed safely and effectively after breast surgeries. We also present our proposed algorithm to provide a stepwise application for selecting the appropriate therapies in the management of more complex PMPS.

Recent Advances in Peripheral Opioid Receptor Therapeutics.

PURPOSE OF REVIEW: Although opioids are excellent analgesics, they are associated with severe short- and long-term side effects that are especially concerning for the treatment of chronic pain. Peripherally acting opioid receptor agonists promise to mitigate the more serious centrally mediated side effects of opioids, and the goal of this paper is to identify and elaborate on recent advances in these peripheral opioid receptor therapeutics. RECENT FINDINGS: Peripheral opioid receptor agonists are effective analgesics that at the same time circumvent the problem of centrally mediated opioid side effects by (1) preferentially targeting peripheral opioid receptors that are often the source of the pain and (2) their markedly diminished permeability or activity across the blood-brain barrier. Recent novel bottom-up approaches have been notable for the design of therapeutics that are either active only at inflamed tissue, as in the case of fentanyl-derived pH-sensitive opioid ligands, or too bulky or hydrophilic to cross the blood-brain barrier, as in the case of morphine covalently bound to hyperbranched polyglycerols. Recent innovations in peripheral opioid receptor therapeutics of pH-sensitive opioid ligands and limiting opioid permeability across the blood-brain barrier have had promising results in animal models. While this is grounds for optimism that some of these therapeutics will be efficacious in human subjects at a future date, each drug must undergo individualized testing for specific chronic pain syndromes to establish not only the nuances of each drug's therapeutic effect but also a comprehensive safety profile.

The Use of L2 and L3 Lumbar Sympathetic Blockade for Cancer-Related Pain, an Experience and Recommendation in the Oncologic Population.

OBJECTIVE: The sympathetic nervous system has a recognized role in transmission of pain, and the lumbar sympathetic blockade is intended to provide analgesia. We share our experiences of lumbar sympathetic blockade in the treatment of cancer-related pain. METHODS: We performed a retrospective analysis of patients with cancer-related pain in the back, abdomen, pelvis, or legs treated at Memorial Sloan Kettering Cancer Center between 2000 and 2018 undergoing lumbar sympathetic blockade at L2 or L3. Blocks were accomplished by injection of local anesthetic or local anesthetic with steroid under fluoroscopy. We measured numerical rating scale scores, percent relief, and relief time. The primary end point was defined as "effective" or "ineffective" pain relief. Effective pain relief was defined as ≥30% relief for at least one day. RESULTS: We identified 124 data points of lumbar sympathetic blockade at L2 or L3, of which 57 were with complete data and used for analysis. Peri-injection, 42 data points had active disease whereas 15 were in remission. Lumbar sympathetic blockade was 67% effective in the back pain cohort, 82% effective in the abdominopelvic pain cohort, and 75% effective in the leg pain cohort. Seventeen data points went on to neurolysis, two to neuromodulation, and eight to intrathecal pump implantation. CONCLUSIONS: Lumbar sympathetic blockade is effective for back, abdominopelvic, and leg pain related to cancer and its treatments. Future research should be aimed at refining its role within multimodal pain management.

Pilot Study in Temporary Peripheral Nerve Stimulation in Oncologic Pain.

OBJECTIVES: Temporary, percutaneous peripheral nerve stimulation (PNS) has been shown to provide analgesia for acute postoperative pain, postamputation pain, and low back pain. The implanted device stimulates the neural target for up to 60 days at which point the leads are extracted. Patients have demonstrated prolonged analgesia continuing after extraction of the leads. The purpose of this case series is to demonstrate peripheral neural targets that could feasibly be used to treat various pain syndromes prevalent in the oncologic population. MATERIALS AND METHODS: A temporary, percutaneous PNS was implanted under ultrasound guidance in 12 oncologic chronic pain patients seen in an outpatient pain clinic who had failed medical and/or interventional management. The device was implanted for up to 60 days. Clinical progress of pain and functional capacity was monitored through regular clinical visits. RESULTS: The case series presents seven successful cases of implementation of the PNS to treat oncologic pain. Three of these cases demonstrate targeting of proximal spinal nerves to treat truncal neuropathic pain and lumbar radicular pain. The four remaining cases demonstrate successful targeting of other peripheral nerves and brachial plexus. We also share five failed cases without adequate pain relief with PNS. CONCLUSIONS: PNS has potential uses in the treatment of oncologic pain. Further high-quality studies should be designed to further elucidate use of the PNS to treat oncologic pain.

Evaluation of Fixed Intrathecal Bupivacaine Infusion Doses in the Oncologic Population.

OBJECTIVES: Intrathecal drug delivery systems (IDDS) are an important method of pain control for patients with refractory oncologic pain. Local anesthetics such as bupivacaine have been infused either alone or with opioids. While effective, bupivacaine can cause adverse effects such as numbness, weakness, and urinary retention. This study looks to establish a safe and efficacious fixed bupivacaine dosing algorithm in intrathecal pumps for cancer patients. MATERIALS AND METHODS: A bupivacaine dosing algorithm was developed using data from 120 previous patients who underwent IDDS placement at Memorial Sloan Kettering Cancer Center. The outcomes were then evaluated for 43 subsequent patients who were treated with bupivacaine IDDS according to our aforementioned algorithm. RESULTS: Our data show that in patients treated with our bupivacaine guideline, visual analog pain scale scores decreased by 59% and oral morphine equivalence decreased by 70% from the period between IDDS implantation until discharge from the MSKCC hospital. However, 16.3% of our patients had bupivacaine-related side effects. CONCLUSIONS: For oncological patients, our data and experience support the initiation of intrathecal bupivacaine at the following doses: 5 mg/day for catheter tips in the cervical spine, 8 mg/day for catheter tips at T1-4, and 10 mg/day for catheter tips at T5-8. Given the higher likelihood of adverse effects in catheters at T9-12 and the lumbar spine, we start at 8 mg/day with close follow-up of the patient. Initiating these doses allow our patients to safely reach adequate analgesia faster, with a shorter hospitalization and quicker return to anti-cancer therapy.

Ultrasound-Guided Serratus Plane Block for Treatment of Postmastectomy Pain Syndromes in Breast Cancer Patients: A Case Series.

Postmastectomy pain syndrome is common after surgical treatment for breast cancer and may be challenging to manage. Currently, there are a wide variety of approaches to treat this type of pain, including medications, physical therapy, and interventional procedures. However, because of the complexity of innervation of the breast, the serratus plane block may better target the web of nerves innervating the anterior chest wall including the breast. We present a case series of 8 patients who were successfully treated with serratus plane block for pain after treatment for breast cancer. We feel that this particular application for the serratus plane block deserves further investigation, as it is relatively easy to perform and has good clinical utility for this type of pain.

Peripheral Nerve Stimulation After Total Knee Arthroplasty and Non-Operable Patella Fracture.

Chronic knee pain, affecting over 25% of adults in the United States, has surged by 65% over the past two decades leading to rising functional deficits, mobility problems, and a diminished quality of life. While conservative management with pharmacologic and minimally invasive injections are pursued early in the disease process, total knee arthroplasty for refractory osteoarthritis of the knee is often considered. This procedure usually improves pain and functionality within the first three months. However, a significant portion of patients often suffer from postoperative pain that can become chronic and debilitating. We detail the case of a patient with a previous TKA as well as a non-operable patella fracture who obtained significant relief with PNS despite prior conservative and minimally invasive management.

Joint hypermobility in functional neurological disorder: A cross-sectional study.

BACKGROUND: Functional Neurological Disorder (FND) is associated with anxiety and depression, and perhaps with joint hypermobility, which is itself associated with anxiety and depression. We conducted a survey to explore the relationship between these. METHODS: An online survey of people with FND was conducted, with participants asked to nominate healthy controls from their social group to join. Participants were asked about their anxiety (measured with GAD7), depression (measured with PHQ9) and joint hypermobility (measured with 5PQ). A regression analysis was conducted using a general linear model. RESULTS: 215 people with FND and 22 people without FND were included in the analysis. GAD7, PHQ9 and hypermobility scores were all higher in the group with FND, with 74% of people with FND meeting the common cut-off for a diagnosis of joint hypermobility syndrome, as compared with 45% of those without FND. Anxiety, depression and joint hypermobility scores all predicted FND status, with joint hypermobility the strongest. Hypermobility moderated the effect of anxiety, with the effect being stronger at lower levels of anxiety. CONCLUSION: While anxiety, depression and hypermobility symptoms each appear to contribute to FND, the role of anxiety is moderated by hypermobility, particularly when anxiety is lower.

Epidural Catheters for Cervical Epidural Steroid Injections to Target Higher Cervical Pathology: Clinical Images in Practice.

Cervical radicular pain is commonly treated with cervical epidural steroid injections. The transforaminal approach allows for direct treatment of the steroid at a particular nerve root or level. Still, it carries a significant risk of morbidity and mortality with thromboembolism or injury to cervical vasculature. The interlaminar approach is commonly utilized as it avoids vascular structures. However, the epidural space becomes narrower at higher levels, limiting the ability to perform this approach at higher cervical levels. Cervical epidural catheters can be used and advanced to target higher cervical pathology through the interlaminar approach. We present clinical images demonstrating the utility of a cervical catheter for treating higher cervical levels.