A Retrospective Analysis of 25 Cases With Peripheral Nerve Field Stimulation for Chronic Low Back Pain and the Predictive Value of Transcutaneous Electrical Nerve Stimulation for Patient Selection

Peripheral Nerve Stimulation for Low Back Pain: A Systematic Review

PURPOSE OF REVIEW

Low back pain (LBP) is a prevalent condition that is associated with diminished physical function, poor mental health outcomes, and reduced quality of life. Peripheral nerve stimulation (PNS) is an emerging modality that has been utilized to treat LBP. The primary objective of this systematic review is to appraise the level of evidence on the efficacy of PNS for treatment of LBP.

RECENT FINDINGS

Twenty-nine articles were included in this systematic review, consisting of 828 total participants utilizing PNS as the primary modality for LBP and 173 participants using PNS as salvage or adjunctive therapy for LBP after SCS placement. Different modalities of PNS therapy were reported across studies, including conventional PNS systems stimulating the lumbar medial branch nerves, peripheral nerve field stimulation (PNFS), and restorative neuromuscular stimulation of the multifidus muscles. All studies consistently reported positive modest to moderate improvement in pain intensity with PNS therapy when comparing baseline pain intensity to each study's respective primary follow-up period. There was a very low GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) quality of evidence supporting this finding. Inconsistency was present in some comparative studies that demonstrated no difference between PNS therapy versus control cohorts (sham or SCS therapy alone), which therefore highlighted the potential for placebo effect. This systematic review highlights that PNS, PNFS, and neuromuscular stimulation may provide modest to moderate pain relief in patients with LBP, although evidence is currently limited due to risk of bias, clinical and methodological heterogeneity, and inconsistency in data.

Efficacy of Peripheral Nerve Field Stimulation for the Management of Chronic Low Back Pain and Persistent Spinal Pain Syndrome: A Narrative Review

OBJECTIVES

Various approaches have been developed with a view to treating the back pain component in patients with chronic low back pain (CLBP) and persistent spinal pain syndrome (PSPS). Emerging evidence shows that peripheral nerve field stimulation (PNFS) may be an efficacious therapeutic modality against axial low back pain. Hence, the aim of the review was to evaluate the analgesic efficacy and safety of PNFS, when used alone or as an adjunct to spinal cord stimulation (SCS), for managing CLBP and PSPS.

MATERIALS AND METHODS

A comprehensive search for clinical studies on PNFS and PNFS + SCS used for the management of CLBP and/or PSPS was performed using PubMed, EMBASE, MEDLINE via Proquest, and Web of Science.

RESULTS

A total of 15 studies were included, of which four were randomized controlled trials (RCTs), nine were observational studies, and two were case series. For patients receiving PNFS, a significant decrease in back pain intensity and analgesic consumption, together with a significant improvement in physical functioning, was observed upon implant of the permanent system. Meanwhile, the addition of PNFS to SCS in refractory cases was associated with a significant reduction in back and leg pain, respectively.

CONCLUSIONS

This review suggests that PNFS, when used alone or in combination with SCS, appears to be effective in managing back pain. However, high-quality evidence that supports the long-term analgesic efficacy and safety is still lacking. Hence, RCTs with a larger patient population and of a longer follow-up duration are warranted.

Preoperative Elevated Levels for Depression, Anxiety, and Subjective Mental Stress Have No Influence on Outcome Measures of Peripheral Nerve Field Stimulation for Chronic Low Back Pain-A Prospective Study

OBJECTIVE

Peripheral nerve field stimulation (PNFS) is an effective alternative treatment for patients with chronic low back pain. The treatment of low back pain strongly depends on psychological factors like anxiety, depression, and mental stress. The aim of this study was to evaluate the impact of such factors on outcome measures after lead- and implantable pulse generator-implantation.

MATERIALS AND METHODS

Between 2014 and 2019, a prospective cohort study of 39 patients with chronic lumbar pain was conducted. Hospital Anxiety and Depression Scale (HADS) score was assessed at baseline to measure symptoms of anxiety and depression. Symptom checklist-90 (SCL-90) was used to measure subjective psychopathology. Pain intensity (numeric pain rating scale [NRS]), SF12v2 with Physical Component Summary and Mental Component Summary (MCS) scores, and Oswestry Disability Index (ODI) were assessed pre- and postoperatively as well as three and six months after PNFS implantation. Outcome values were compared to baseline data. Statistical analysis was performed using depending t-test and analysis of variance (ANOVA). A p value <0.05 was considered significant.

RESULTS

The cohort consisted of 39 patients (18 females, 21 males) with a median age of 61 years (IQR^25-75  = 52-67 years). NRS, ODI, and SF12v2 showed significant improvement in the whole follow-up period compared to baseline values (p < 0.05). Elevated HADS scores for anxiety were seen in 64.1%, for depression in 76.9% of the patients at baseline. SCL-90 was pathologic in 71.8% of the cases. A one-way ANOVA revealed no differences between elevated HADS- and SCL-90 values and all outcome measures after PNFS implantation in the whole follow-up period (p > 0.05).

CONCLUSION

Chronic low back pain is often associated with psychological distress. Our study showed highly elevated levels for anxiety and depression as well as subjective mental stress in patients with chronic low back pain without negative impact on NRS, ODI, and SF12v2 in the whole follow-up after PNFS implantation.

The Predictive Value of Transcutaneous Electrical Nerve Stimulation for Patient Selection in Peripheral Nerve Field Stimulation for Chronic Low Back Pain: A Prospective Study

OBJECTIVE

Peripheral nerve field stimulation (PNFS) is an effective alternative treatment for patients with chronic low back pain. Transcutaneous electrical nerve stimulation (TENS) is frequently used in pain therapy. Aim of this prospective study was to examine the predictive value of TENS for later PNFS treatment.

MATERIALS AND METHODS

Between 2014 and 2019, a prospective cohort study of 41 patients with chronic lumbar pain was conducted. Pain intensity (NRS) was assessed before and after TENS use, preoperatively/postoperatively and in the follow-up after three and six months, SF12v2 questionnaires with physical (PCS) and mental component summary (MCS) scores, and Oswestry disability index (ODI) questionnaire at baseline as well as three and six months after PNFS implantation. Implantation of the PNFS-system with two percutaneous leads was performed after four to seven days of positive testing. Statistical analysis was performed using depending t-test, ANOVA, and Spearman correlation.

RESULTS

The cohort consisted of 41 patients (19 females, 22 males) with a median age of 60.5 years (IQR^25-75 52-67). Two patients were lost to follow-up. After positive PNFS testing a pulse generator (IPG) was implanted in 15 patients with positive TENS effect and 15 patients without TENS effect. Leads were explanted in nine patients after negative PNFS trial phase. TENS positive patients showed significant correlation to a positive effect in the PNFS trial phase in NRS reduction (p = 0.042) indicating that TENS responders will also respond to PNFS (94% patients). After three and six months follow-up median NRS and SF12v2 (PCS) improved significantly in both cohorts, SF12v2 (MCS) and ODI only in the TENS positive cohort, respectively.

CONCLUSION

TENS can be predictive for patient selection in PNFS, as TENS positive patients showed significant correlation with a positive PNFS trial period. Therefore, TENS positive patients might be justifiable to be directly implanted with leads and IPG. TENS positive patients further tend to show a better improvement in the follow-up.

A review of the bioelectronic implications of stimulation of the peripheral nervous system for chronic pain conditions

Background

Peripheral Nerve Stimulation has been used to treat human disease including pain for several decades. Innovation has made it a more viable option for treatment of common chronic pain processes, and interest in the therapy is increasing.

Main body

While clinical data is forthcoming, understanding factors that influence successful outcomes in the use of PNS still needs to be delineated. This article reviews the evolution and bioelectronic principles of peripheral nerve stimulation including patient selection, nerve targets, techniques and guidance of target delivery. We collate the current evidence for outcomes and provide recommendations for salient topics in PNS.

Conclusion

Peripheral nerve stimulation has evolved from a surgically invasive procedure to a minimally invasive technique that can be used early in the treatment of peripheral nerve pain. This review identifies and addresses many of the variables which influence the success of PNS in the clinical setting.