Peripheral nerve stimulation for saphenous neuralgia.

BACKGROUND: Injury to saphenous nerve branches is frequent during knee surgery and can result in chronic pain. This saphenous neuralgia remains challenging to treat. Peripheral nerve stimulation (PNS) is a new potential non-pharmacologic treatment option. We present our outcomes experience using this technology in 12 patients. METHODS: We retrospectively reviewed PNS placement for saphenous neuralgia between 2000 and 2022 at a single institution. Demographic information was collected as well as response to the device. Four-question short-form Patient-Reported Outcome Measurement Information System (PROMIS) Scores were collected before and 2 weeks, 6 weeks, and 6 months postprocedure. Specific scores included pain interference and behavior, functional mobility, depression, anxiety, and sleep impairment. Change in pain interference measured by the short-form PROMIS tool at 6 months was chosen as the primary outcome. RESULTS: Twelve patients met inclusion criteria, with 10 patients having the full 6-month follow-up. In these 10 patients, the mean change from baseline in the short-form adjusted pain interference score (greater difference means improved pain) at 6 months was 5.8 (SD 6.5). Among all patients, average follow-up was 11.5 months (range 3-35 months). Most patients' symptoms developed after knee surgery (84%). Prior to PNS, patients underwent other treatments including cryoablation (8%), radiofrequency ablation (16%), saphenous neurectomy (16%), or surgical release of adjacent nerves (25%). Ten patients (83%) reported any improvement in symptoms while two reported no benefit. Complications occurred in four patients (33%). Two patients had the device removed and a third discontinued use. PROMIS Scores for pain, functional mobility, mood, and sleep impairment all improved. DISCUSSION: Limited effective treatments exist for saphenous neuralgia. Our case series demonstrates the potential of PNS as a treatment for saphenous neuralgia. Comparative effectiveness studies are warranted to assess whether our effect size is clinically relevant.

Transitional Pain Medicine; New Era, New Opportunities, and New Journey.

Chronic postsurgical pain (CPSP), also known as persistent postsurgical pain (PPSP), is pain that develops or increases in intensity after a surgical procedure and lasts more than 3 months. Transitional pain medicine is the medical field that focuses on understanding the mechanisms of CPSP and defining risk factors and developing preventive treatments. Unfortunately, one significant challenge is the risk of developing opioid use dependence. Multiple risk factors have been discovered, with the most common, and modifiable, being uncontrolled acute postoperative pain; preoperative anxiety and depression; and preoperative site pain, chronic pain, and opioid use.

Review of Ultrasound-Guided Procedures in the Management of Chronic Pain.

This article summarizes clinical expert recommendations and findings for the application of ultrasound-guided procedures in chronic pain management. Data on analgesic outcomes and adverse effects were collected and analyzed and are reported in this narrative review. Ultrasound guidance offers opportunities for the treatment of pain, with focus in this article on greater occipital nerve, trigeminal nerves, sphenopalatine ganglion, stellate ganglion, suprascapular nerve, median nerve, radial nerve, ulnar nerve, transverse abdominal plane block, quadratus lumborum, rectus sheath, anterior cutaneous abdominal nerves, pectoralis and serratus plane, erector spinae plane, illioinguinal/iliohypogastric/genitofemoral nerve, lateral femoral cutaneous nerve, genicular nerve, and foot and ankle nerves.

Clinical Approach to Chronic Pain due to Perioperative Nerve Injury.

Perioperative nerve injuries are common and may be prevented. The estimated incidence of perioperative nerve injury is 10% to 50%. However, most of these injuries are minor and self-recovering. Severe injuries account for up to 10%. Potential mechanisms of injury are nerve stretch, compression, hypoperfusion, direct nerve trauma, or injury during vessel cannulation. Nerve injury pain usually presents as neuropathic pain ranging from mild to severe mononeuropathy and extends to the disabling complex regional pain syndrome. This review provides a clinical approach to subacute and chronic pain secondary to perioperative nerve injury, presentation, and management.

Role of peripheral nerve stimulation in treating chronic neuropathic pain: an international focused survey of pain medicine experts.

Interventional pain management (IPM) options for refractory neuropathic pain (NP) have recently increased with availability of peripheral nerve stimulation (PNS) equipment and expertise. Given a lack of high-quality evidence and guidelines on this topic, we sought to understand the perception of physicians with expertise in treating NP regarding IPM and the role of PNS. We emailed a survey in March 2022 to international NP experts including pain medicine physicians, researchers, and leaders of 11 professional pain societies. No representatives from vendors of PNS systems were included in the design of the survey nor as respondents. Among 24 respondents (67% of those contacted), the distal common peroneal, tibial, and sural nerves were most frequently targeted (60%) with PNS. Persistent postsurgical pain of more than 3 months was the most common indication for PNS (84%). The aggregate NP treatment algorithm in order of median rank was non-opioid medications as first line, IPM including epidural/perineural steroid injections tied with transcutaneous electrical nerve stimulation as second line, pulsed radiofrequency (RF) tied with RF ablation/denervation as third line, temporary then permanent PNS as fourth line, followed by spinal cord stimulation, opioids, cryoablation, botulinum, peripheral nerve field stimulation, intrathecal targeted drug delivery, and others. Before offering PNS, 12 respondents (50%) indicated their preference for trialing non-neuromodulation treatments for 1-3 months. Twenty-two respondents (92%) agreed PNS should be offered early in the treatment of neuropathic pain. The most common barriers to PNS use were cost, lack of high-quality evidence in support of its use, lack of exposure to PNS in training programs, and lack of familiarity with the use of ultrasound guidance. PNS appears to have an increasing role in the treatment of NP but more research is needed on the outcomes of PNS to elucidate its role.

Assessment of outcomes in consecutive patients undergoing dorsal scapular nerve decompression.

OBJECTIVE: Periscapular pain has a broad differential diagnosis. Dorsal scapular neuropathy is part of that differential diagnosis but is often forgotten by clinicians, leading to delayed diagnosis, chronic pain, and potentially worse outcomes. The objective of this study was to describe our method for diagnosis, surgical technique, intraoperative findings, and outcomes in consecutive patients undergoing dorsal scapular nerve (DSN) decompression. METHODS: A retrospective cohort study was performed to compile and describe outcomes for consecutive patients (n = 21) who underwent DSN decompression by a single surgeon during the period between August 2018 and February 2021. The primary outcome was change in visual analog scale (VAS) score for periscapular pain between baseline and 6 months postoperatively. Secondary outcomes included change in VAS score for overall pain, change in Disabilities of the Arm, Shoulder, and Hand (DASH) score, and change in the Zung Self-Rating Depression Scale (Zung SDS) between baseline and 6 and 12 months postoperatively. RESULTS: Patients undergoing DSN decompression showed significant improvement in VAS score for periscapular pain between baseline and 6 months postoperatively (mean score 54.0 vs 26.8, respectively; p < 0.001). Fifteen of 21 patients (71%) had a good outcome (score improvement ≥ 20). Disability (as determined by DASH scores) was significantly improved at 6 and 12 months postoperatively. The only factor that was predictive of outcome was symptom duration, with longer symptom duration predicting a poor outcome. CONCLUSIONS: Surgical treatment of dorsal scapular neuropathy is associated with significant improvements in pain and disability, and these improvements are durable. Morbidity associated with surgical treatment is low.

Application of multidisciplinary team conference for neuromodulation candidates facilitates patient selection and optimization.

Introduction: Psychological evaluation is required by insurance companies in the United States prior to proceeding with a spinal cord stimulation or a dorsal root ganglion stimulation trial. Since January 2017, we implemented a Multidisciplinary Team Conference for Neuromodulation in our center to facilitate the collaboration between pain physicians and psychologists and to optimize screening of neuromodulation candidates. This study aims to report the impact of this team conference on improvement of neuromodulation outcome in our center. Methods: Appropriateness of neuromodulation were discussed in the team conference after initial visit with the pain specialist and psychological evaluation. For this study, we prospectively and retrospectively collected data on neuromodulation candidates who went through the team conference and those who did not as controls. Results: We discussed 461 patients in the team conference sessions from January 2017 to July 2023. Out of these, a spinal cord stimulator or a dorsal root ganglion stimulator trial was performed in 164 patients with 80.5% (132 cases) trial success rate leading to 140 implants. Out of these implants, 26 (18.6%) explanted and 21 (15%) required revision in 41 (29.3%) patients. We performed neuraxial neuromodulation trial for 70 patients without going through the team conference from January 2016 to July 2023 with a trial success rate of 45.7% (32 cases). In this group, 7 (21.9%) and 6 (18.8%) patients underwent explant and revision. The differences between the groups were statistically significant for trial success rate (odds ratio of 4.9 with p-value of <0.01) but not for explant (odds ratio of 0.8 with p-value of 0.627) or revision (odds ratio of 0.8 with p-value of 0.595). Conclusion: Implementing Multidisciplinary Team Conference increased trial success rate in our center. Team conference provides therapeutic benefit for patients, and also provides the opportunity for an educational discussion for trainees.

Application of the novel Nalu™ Neurostimulation System for peripheral nerve stimulation.

Peripheral nerve stimulation is an established treatment modality for chronic neuropathic pain. Over the last decade, with the advent of innovative devices and delivery platforms, peripheral nerve stimulation has evolved from invasive open surgeries to image-guided, minimally invasive percutaneous procedures. The authors hereby present a novel device, the Nalu™ Neurostimulation System (Nalu Medical, CA, USA), which has established its advantages in providing predictable and reliable peripheral nerve stimulation therapy for chronic neuropathic pain management. This novel device is effective in treating chronic pain conditions such as post-herniorrhaphy pain syndrome, intercostal neuralgia, post-laminectomy syndrome, and complex regional pain syndrome and holds great promise for the treatment of peripheral neuropathic pain.

Chronic nerve pain is a debilitating condition that can affect quality of life and functioning. The Nalu™ Neurostimulation System (Nalu Medical, CA, USA) provides long-term pain relief without medications. There are numerous devices currently available that can be utilized to block pain signals using small wires. This system is unique because the wires placed over affected nerves are powered by an external battery that does not require permanent surgical implantation. Pain after hernia surgery, back surgery, hip surgery and knee surgery, as well as nerve pain can be effectively managed by this system.

Considerations in permanent implantation of peripheral nerve stimulation (PNS) for chronic neuropathic pain: An international cross-sectional survey of implanters.

AIM: Novel minimally invasive short-term and long-term peripheral nerve stimulation (PNS) systems have revolutionized targeted treatment of chronic neuropathic pain. We present an international survey of PNS-implanting pain physicians to assess what factors they consider when offering permanent PNS. METHODS: This cross-sectional study consisted of a survey (Qualtrics) that was distributed to PNS-implanting physicians in a device supplier's entire email database on November 13, 2020, with 3 weeks of response time. Physicians' contact information in the form of their email addresses had been previously collected by the supplier upon device distribution with permission to use survey responses for research. RESULTS: Of 2032 database physicians, 40 physicians representing 37 institutions responded to the survey. The most common application of PNS was mononeuropathic pain (57%). The most frequently targeted nerve was the suprascapular nerve (29%). 14% of physicians reported 81-100% of their implants were dual-lead. The representative physicians ranged broadly in their most frequently targeted nerves. Although mononeuropathic pain was the most common indication for PNS, there was still varied response regarding other indications such as CRPS and post-surgical chronic pain. CONCLUSION: In context of a low response rate, identifying such factors can help update the prevailing treatment algorithm for interventional therapies, assist pain physicians in better identifying which patients are the best candidates for PNS, and inform future clinical trial design on PNS efficacy.

Understanding the role of patient preference in the treatment algorithm for chronic low back pain: results from a survey-based study.

Aims: Interventional pain treatments range from injections to established radiofrequency ablation techniques and finally neuromodulation. In addition to safety, efficacy and cost dominance, patient preference for type of treatment is important. Methods: Chronic pain patients (n = 129) completed a preference scale to determine which interventional pain management procedures they would prefer from among radiofrequency ablation, temporary (60-day) peripheral nerve stimulation (PNS), conventional PNS and spinal cord stimulation/dorsal root ganglion stimulation. A second survey (n = 347) specific to assessing the preference for radiofrequency ablation or temporary PNS treatment was completed by patients with low back pain. Results: On the basis of mean rank, temporary PNS percutaneously implanted for up to 60 days was the most preferred treatment compared with the other options presented (p = 0.002). Conclusions: Patient preference should be unbiased and considered as an independent variable for physician discussion in treatment options and future research.

Patient preference is an important variable for physicians to consider when discussing treatment options for low back pain. A consumer survey study was completed discussing patient preference among various invasive treatments for low back pain. When given scenarios discussing risks and benefits of each procedure (temporary peripheral nerve stimulation for 60 days, heat ablation of small back nerves and permanently implanted back pain devices) temporary peripheral nerve stimulation was considered the preferred option.

Peripheral Nerve Stimulation for Occipital Neuralgia.

BACKGROUND: Chronic headaches are the second most prevalent disease and second most common cause for years lived with disability worldwide. Occipital neuralgia can cause headaches or be present in addition to other more prevalent causes of headache. If these headaches fail to respond to conservative and pharmacological therapy, physicians proceed to more invasive treatments, starting with infiltration of the greater occipital nerve with local anesthetic with or without corticosteroids, followed by nerve ablation or stimulation. Occipital nerve stimulation gained more popularity as the technology improved and more pain physicians received training on interventional procedures. METHODS: In this manuscript, we are presenting our experience with ultrasound-guided implant of occipital nerve stimulators using peripheral nerve stimulator systems. After confirming appropriateness of treatment by a successful occipital nerve block (i.e., resulting in >50% relief in patients' pain intensity), we implanted five stimulator systems in three patients (two bilateral). RESULTS: We followed these patients for an average of eight months, and the average pain reduction was ∼50%. We did not observe any adverse events during or immediately after surgery. One patient developed an adverse reaction to the adhesive of the battery transmitter, but it was not severe enough to stop her from using the stimulator. CONCLUSIONS: Considering the ease of implant and minimal side effects, implant of peripheral nerve stimulators to stimulate the occipital nerve is a promising treatment modality for patients with chronic headache who present with features of occipital neuralgia. However, wider use of this treatment modality is subject to further studies.

History of Peripheral Nerve Stimulation-Update for the 21st Century.

OBJECTIVE: To present a history of the development of peripheral nerve stimulation. METHODS: Narrative literature review. RESULTS: Peripheral nerve stimulation has a history stretching from Scribonius Largus and eels in Mesopotamia to Michael Farady's discovery in London, the German-English physician Julius Althaus's application of electricity to a peripheral nerve, the sensational "Electreat" in the United States, to the application by Wall and Sweet of the gate theory proposed by Melzack and Wall to specialized neurosurgeons. CONCLUSIONS: This is now a modern field in clinical neuroscience and medicine with improved technology, renewed interest by a diverse range of specialties, and accessibility with ultrasound.

The Regenerative Potential of Therapeutic Ultrasound on Neural Tissue: A Pragmatic Review.

OBJECTIVES: Low-intensity ultrasound (LIU)/low-intensity pulsed ultrasound (LIPUS) may influence nerve tissue regeneration and axonal changes in the context of carpal tunnel syndrome (CTS) and in the animal model. The purpose of this pragmatic review is to understand the current knowledge for the effects of low-intensity therapeutic ultrasound in the animal and human model and determine the future directions of this novel field. DESIGN: Pragmatic review. METHODS: We performed a literature search of available material using OVID, EmBase, and PubMed for LIU/LIPUS, all of which were preclinical trials, case reports, and case series using animal models. For CTS, a literature search was performed on PubMed (1954 to 2019), CENTRAL (the Cochrane Library, 1970 to 2018), Web of Science (1954 to 2019), and SCOPUS (1954 to 2019) to retrieve randomized controlled trials. RESULTS: Eight articles were discussed showing the potential effects of LIU on nerve regeneration in the animal model. Each of these trials demonstrated evidence of nerve regeneration in the animal model using LIPUS or LIU. Seven randomized controlled trials were reviewed for ultrasound effects for the treatment of carpal tunnel syndrome, each showing clinical efficacy comparable to other treatment modalities. CONCLUSIONS: LIU/LIPUS is a promising and noninvasive means of facilitating nerve regeneration in the animal model and in the treatment of carpal tunnel syndrome. Although many of the trials included in this review are preclinical, each demonstrates promising outcomes that could eventually be extrapolated into human studies.

Therapeutic Ultrasound for Pain Management in Chronic Low Back Pain and Chronic Neck Pain: A Systematic Review.

BACKGROUND: Low back pain (LBP) and neck pain are major causes of pain and disability that are experienced across all ages. The primary goals of treatment are to improve patient function and facilitate a return to the patient's desired level of daily activity. Therapeutic ultrasound is a noninvasive modality widely utilized in the management of musculoskeletal disorders, but there continues to be controversy regarding its use due to insufficient evidence of effectiveness. The objective of this systematic review was to evaluate the effectiveness of therapeutic ultrasound in the management of patients with chronic LBP and neck pain. METHODS: Using PRISMA guidelines, a search of the PubMed and CENTRAL (The Cochrane Library) databases was performed to retrieve randomized controlled trials (RCTs) that evaluated therapeutic ultrasound in patients with chronic LBP or neck pain. RESULTS: The search strategy identified 10 trials that met the criteria for inclusion. Three studies in LBP reported that both therapeutic and sham (placebo) ultrasound provided significant improvement in pain intensity. In each of these studies, ultrasound was found to be more effective than placebo when using only one of several validated instruments to measure pain. Three of the four studies on neck pain demonstrated significant pain relief with ultrasound in combination with other treatment modalities. However, only one of these studies demonstrated that the use of ultrasound was the cause of the statistically significant improvement in pain intensity. CONCLUSIONS: Therapeutic ultrasound is frequently used in the treatment of LBP and neck pain and is often combined with other physiotherapeutic modalities. However, given the paucity of trials and conflicting results, we cannot recommend the use of monotherapeutic ultrasound for chronic LBP or neck pain. It does seem that ultrasound may be considered as part of a physical modality treatment plan that may be potentially helpful for short-term pain relief; however, it is undetermined which modality may be superior. In both pain syndromes, further trials are needed to define the true effect of low-intensity ultrasound therapy for axial back pain. No conclusive recommendations may be made for optimal settings or session duration.

Therapeutic Ultrasound for Chronic Pain Management in Joints: A Systematic Review.

BACKGROUND: Treatments for joint pain and dysfunction focus on restoration of joint motion, improvement in pain and a return to the previous level of the patient's daily activity. Therapeutic ultrasound is a noninvasive modality widely utilized in the management of musculoskeletal disorders. The objective of this systematic review was to evaluate the effectiveness of therapeutic ultrasound in the management of patients with knee, shoulder and hip pain. METHODS: Using PRISMA guidelines, a search of the PubMed, CENTRAL (The Cochrane Library), Web of Science and Scopus databases was performed to retrieve randomized controlled trials (RCTs) that evaluated therapeutic ultrasound (continuous and pulsed) in patients with chronic knee, shoulder and hip pain. RESULTS: The search strategy identified 8 trials for knee, 7 trials for shoulder and 0 trials for hip that met the criteria for inclusion. All 8 trials showed improvement in knee pain, and of these studies 3 showed statistical significance improvement for therapeutic ultrasound versus the comparator. For shoulder pain, all 7 trials showed reduction in pain, but should be noted that 4 of studies demonstrated that therapeutic ultrasound is inferior to the comparator modality. CONCLUSION: Therapeutic ultrasound is frequently used in the treatment of knee, shoulder and hip pain and is often combined with other physiotherapeutic modalities. The literature on knee arthritis is most robust, with some evidence supporting therapeutic ultrasound, though the delivery method of ultrasound (pulsed vs continuous) is controversial. As a monotherapy, ultrasound treatment may not have a significant impact on functional improvement but can be a reasonable adjunct to consider with other common modalities. In all three pain syndromes, especially for hip pain, further trials are needed to define the true effect of low-intensity ultrasound therapy knee, shoulder and hip pain. No conclusive recommendations may be made for optimal settings or session duration.

A Case Report of Combined Ultrasound and Fluoroscopic-Guided Percutaneous Radiofrequency Lesioning of the Obturator and Femoral Articular Branches in the Treatment of Persistent Hip Pain in a Pediatric Patient.

Hip denervation comprising radiofrequency lesioning of the obturator and femoral articular branches is used in adults with refractory hip pain who are not surgical candidates. Persistent hip pain occurs infrequently in pediatric patients, and there are limited data on the safety and efficacy of this procedure in a pediatric population. We provide a case report of a successful ultrasound and fluoroscopic-guided hip denervation procedure in an 11-year-old girl with persistent right hip pain after septic arthritis refractory to conservative and surgical management. At an 18-week follow-up, hip denervation provided improvement in pain, mobility, and reduced opioid consumption by 20%.

Perioperative interventions to reduce chronic postsurgical pain.

Approximately 10% of patients following a variety of surgeries develop chronic postsurgical pain. Reducing chronic postoperative pain is especially important to reconstructive surgeons because common operations such as breast and limb reconstruction have even higher risk for developing chronic postsurgical pain. Animal studies of posttraumatic nerve injury pain demonstrate that there is a critical time frame before and immediately after nerve injury in which specific interventions can reduce the incidence and intensity of chronic neuropathic pain behaviors-so called "preventative analgesia." In animal models, perineural local anesthetic, systemic intravenous local anesthetic, perineural clonidine, systemic gabapentin, systemic tricyclic antidepressants, and minocycline have each been shown to reduce pain behaviors days to weeks after treatment. The translation of this work to humans also suggests that brief perioperative interventions may protect patients from developing new chronic postsurgical pain. Recent clinical trial data show that there is an opportunity during the perioperative period to dramatically reduce the incidence and severity of chronic postsurgical pain. The surgeon, working with the anesthesiologist, has the ability to modify both early and chronic postoperative pain by implementing an evidence-based preventative analgesia plan.