Pain intensity and opioid consumption after temporary and permanent peripheral nerve stimulation: a 2-year multicenter analysis

OBJECTIVE

Peripheral nerve stimulation (PNS) is an emerging neuromodulation modality, yet there remains limited data highlighting its long-term effectiveness. The objective of this study was to report real-world data on pain intensity and opioid consumption after temporary and permanent PNS for chronic pain up to 24 months postimplantation.

METHODS

A retrospective study was conducted on all patients who received PNS implants at a multi-centered enterprise between January 1, 2014 and February 24, 2022. The two co-primary outcomes were: (1) change in pain intensity (11-point Numerical Rating Scale) from baseline to 12 months postimplant; and (2) comparison of the change in pain intensity between temporary and permanent PNS cohorts 12 months postimplant.

RESULTS

126 patients were included in this analysis. Pain intensity significantly decreased 12 months postimplant in the overall cohort (mean difference (MD) -3.0 (95% CI -3.5 to -2.4), p<0.0001). No significant difference in this reduction was identified between temporary and permanent PNS cohorts (MD 0.0 (95% CI -1.1 to 1.0), p=1.00) 12 months postimplantation. Pain intensity significantly decreased in the overall, temporary, and permanent cohorts at all secondary time points (3, 6, and 24 months). No change in daily opioid consumption was observed at 6 and 12 months postimplant in the overall cohort.

CONCLUSION

This study found that both temporary and permanent PNS may be effective for reducing pain intensity in patients with chronic pain up to 24 months postimplantation, although no changes in opioid consumption were observed. The decrease in pain intensity was comparable between patients receiving temporary versus permanent implants, highlighting that temporary PNS may achieve long-lasting clinical benefits. However, given the substantial loss to follow-up, further large-scale studies are needed to solidify conclusions about the efficacy of PNS.

Novel implantation technique for pudendal nerve peripheral nerve stimulation for treatment of chronic pelvic pain

BACKGROUND

Chronic pelvic pain (CPP) is a pervasive, difficult to treat condition affecting up to 26% of the global female and 8.2% of the global male population. Considered a form of chronic regional pain syndrome (CRPS), it is medically complex and often refractory to multimodal management. Neuromodulation has become increasingly popular in treatment of chronic neuropathic pain conditions, including CPP and CRPS. Dorsal column spinal cord stimulation and dorsal root ganglion stimulation have had some success for managing CPP meanwhile peripheral nerve stimulators (PNS) have been suggested as another viable option. However, few studies in the literature have reported successful use of PNS in treatment of CPP. Here, we detail a possible technique for pudendal PNS lead placement for management of CPP.

METHOD

This article describes a novel cephalad to caudad fluoroscopic guided technique for pudendal nerve PNS lead placement and implantation.

RESULTS

A cephalad to caudal-medial fluoroscopic guided approach as described within to successfully implant a percutaneous pudendal nerve PNS for management of CPP.

CONCLUSIONS

The pudendal nerve PNS lead placement technique noted within can be used to avoid many of the important neurovascular structures near the pelvic outlet. Further studies are needed to validate the safety and efficacy of this therapy modality but it may be a viable management option for patients with medically refractory CPP.

Ischiorectal Approach to Cryoablation of the Pudendal Nerve Using a Handheld Device: A Report of Two Cases

The pudendal nerve is situated deep within the pelvis and is a challenge to target for pain interventions due to the theoretical risk of incontinence with manipulation. The management of pudendal neuralgia using cryoablation is currently limited as it has historically required computed tomography (CT) guidance by interventional radiologists. Through this report, we describe a safe, reproducible, ischiorectal fossa approach to pudendal nerve cryoablation with a handheld device utilizing anatomical landmarks, nerve stimulation, and fluoroscopy. Two patients with longstanding pelvic pain and positive response to diagnostic pudendal nerve blocks underwent bilateral cryoablation of the pudendal nerves. This procedure was performed with the patients in prone positioning and percutaneous insertion of a cryoablation probe medial to the ischial tuberosity and lateral to the rectum. Correct positioning on the pudendal nerve was achieved with nerve stimulation eliciting visible anal sphincter contraction, and fluoroscopic imaging of the probe relative to the ischial spine. The probe was set to -88 Celsius for 108 seconds and a total of two cycles were performed. Pain reduction was reported for 3-4 months and repeat cryoablation was similarly efficacious with no evidence of incontinence. This technique, we believe minimizes risks and simplifies cryoablation to be performed on an outpatient basis by more pain physicians.

Pain specialist management of sexual pain: III-neuromodulation

INTRODUCTION

Some women with sexual pain do not respond to conservative multi-modal care modalities. Neuromodulation is a group of methods which alter nerve activity by delivering electrical energy or pharmaceutical agents directly to target neural structures. Multiple forms of neuromodulation may provide durable treatment options to fill the unmet therapeutic need of a certain population of women with chronic sexual pain.

OBJECTIVES

To provide a current review of neuromodulation treatments used for female sexual pain and introduce neuromodulation techniques which may be applied in novel ways to specific sexual pain phenotypes.

METHODS

Internet, PubMed and Cochrane Library were searched for relevant articles on female sexual pain within the clinical purview and scope of practice of pain management.

RESULTS

A thorough review of the literature was conducted to include basic science studies, clinical trials, systematic reviews, consensus statements, and case-reports. A sampling of information on real-world patient outcomes was included. The amount and quality of evidence for neuromodulation to treat female sexual pain is low-moderate. Descriptions of neuromodulation procedures for sexual pain were made and clinical studies reviewed. The effects of autonomic nervous system (ANS) dysregulation on the experience of pain were discussed with consideration of interventional procedures to facilitate restoration of ANS equilibrium.

CONCLUSION

Treating female sexual pain is complex. There are considerable numbers of women who have unsatisfactory sexual pain relief despite evidence-based interdisciplinary care. These women may benefit from referral to consider neuromodulation treatment options. Neuromodulation is a relatively new capability in the arsenal of pain management and other specialists that can be considered for women with treatment refractory sexual pain.

Diagnosis and treatment of pudendal and inferior cluneal nerve entrapment syndrome: a narrative review

AIM

Pudendal and inferior cluneal nerve entrapment can cause a neuropathic pain syndrome in the sensitive areas innervated by these nerves. Diagnosis is challenging and patients often suffer several years before diagnosis is made. The purpose of the review was to inform healthcare workers about this disease and to provide a basis of anatomy and physiopathology, to inform about diagnostic tools and invasive or non-invasive treatment modalities and outcome.

METHODS

A description of pudendal and inferior cluneal nerve anatomy is given. Physiopathology for entrapment is explained. Diagnostic criteria are described, and all non-invasive and invasive treatment options are discussed.

RESULTS

The Nantes criteria offer a solid basis for diagnosing this rare condition. Treatment should be offered in a pluri-disciplinary setting and consists of avoidance of painful stimuli, physiotherapy, psychotherapy, pharmacological treatment led by tricyclic antidepressants and anticonvulsants. Nerve blocks are efficient at short term and serve mainly as a diagnostic tool. Pulsed radiofrequency (PRF) is described as a successful treatment option for pudendal neuralgia in patients non-responding to non-invasive treatment. If all other treatments fail, surgery can be offered. Different surgical procedures exist but only the open transgluteal approach has proven its efficacy compared to medical treatment. The minimal-invasive ENTRAMI technique offers the possibility to combine nerve release with pudendal neuromodulation.

CONCLUSIONS

Pudendal and inferior cluneal nerve entrapment syndrome are a challenge not only for diagnosis but also for treatment. Different non-invasive and invasive treatment options exist and should be offered in a pluri-disciplinary setting.

Sonoanatomy of the ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves: a practical guide for US-guided injections

The ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves are the major sensory nerves that may be involved in chronic groin and genital pain with a significant impact on the quality of life of patients. The diagnosis remains clinical, and US-guided diagnostic injections using an anesthetic may aid in confirming the clinical suspicion. The anatomy of the peripheral nerves can be successfully studied using imaging. High-resolution ultrasound is increasingly used in the clinical setting for visualizing small peripheral nerves, and magnetic resonance imaging provides an anatomical overview of the relationship between small nerves and surrounding structures. In this pictorial assay, we review the anatomy and clinical relevance of the ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves. We summarize the various techniques for ultrasound identification, and present the ultrasound-guided infiltration techniques for injecting the ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves. Corresponding magnetic resonance images and clinical photos of the probe placement technique are provided for anatomical correlation. This paper is aimed to serve as a practical technical guide for physicians to familiarize themselves with the ultrasound anatomy of the major inguinal sensory nerves and to enable successful ultrasound identification and ultrasound-guided diagnostic or therapeutic infiltrations for pain management of the ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves.

Advances in the therapeutic approach of pudendal neuralgia: a systematic review

CONTEXT

Although pudendal neuralgia (PN) has received growing interest over the last few years, diagnosis remains difficult, and many different therapeutic approaches can be considered.

OBJECTIVES

This article aims to provide an overview of the possible treatments of PN and investigate their efficacies.

METHODS

Utilizing PubMed and ScienceDirect databases, a systematic review was carried out and allowed identification of studies involving patients with PN, as defined by Nantes criteria, and their associated treatments. Relevant data were manually reported.

RESULTS

Twenty-eight articles were selected, totaling 1,013 patients (mean age, 49 years) and six different types of interventions. Clinical outcomes, most frequently quantified utilizing the Visual Analog Scale (VAS), vary greatly with both the therapy and time after intervention (from 100 to <10%). However, neither peri nor postoperative serious complications (grade > II of Clavien-Dindo classification) are reported. Although surgery seems to provide a higher proportion of long-term benefits, identifying the most efficient therapeutic approach is made impossible by the multitude of outcome measurements and follow-up frequencies. It should also be noted that literature is sparse regarding randomized controlled trials with long-term follow-up.

CONCLUSIONS

Although there are a number of modalities utilized for the treatment of PN, there are no current recommendations based on treatment efficacies. This seems to be largely in part caused by the lack of standardization in outcome quantification. Future research in this field should focus on prospective cohort studies with high levels of evidence, aimed at assessing the long-term, if not permanent, benefits of available therapies.

The short-term efficacy of electrical pudendal nerve stimulation versus intravesical instillation for the urethral pain syndrome: a randomized clinical trial

PURPOSE

Urethral pain syndrome is a chronic condition characterized by disturbing feeling or server pain sensed at the urethra without specific treatment. This double-center, two-arm controlled trial aimed to explore the efficacy of electrical pudendal nerve stimulation (EPNS) versus intravesical instillation (II) of heparin and alkalinized lidocaine for urethral pain syndrome (UPS).

METHODS

Eighty eligible patients took three sessions of EPNS, or 1 session of II per week, for 6 consecutive weeks. The primary end point was the change of pelvic pain and urgency/frequency symptom (PUF) score from baseline to week 6. Secondary outcome measures included changes of visual analogue scale (VAS) score and three sub-score extracted from PUF score.

RESULTS

The enrolled participants were all included in the intention-to-treat analyses, and baseline characteristics between the two groups were well balanced. The post-treatment PUF score decreased by 10.0 (7.00, 16.50) in the EPNS group, and by 7.0 (3.00, 10.00) in the II group. At the closure of treatment, the medians of changes in symptom score, bother score, pain-related score and VAS score were 6.50 (4.25, 10.00), 4.00 (2.00, 6.00), 6.00 (5.00, 8.00),4.50 (2.25, 6.00), respectively, in the EPNS group, and 4.00 (2.00, 7.00), 3.00 (1.00, 3.00), 3.00 (2.00, 6.00), 2.00 (1.00, 4.00), respectively, in the II group. All the between-group differences were statistically significant.

CONCLUSION

Compared with the II, the EPNS results in superior pain control and better relief of lower urinary tract symptoms, and deserves further attention.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03671993).