Efficacy of Percutaneous Adhesiolysis in Managing Low Back and Lower Extremity Pain: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Chronic refractory low back pain with or without lower extremity pain that does not resolve after conservative therapy or even surgical treatment can present a therapeutic dilemma with limited options for proper management [1‐8]. Low back and lower extremity pain recalcitrant to conservative management and epidural injections may be secondary to postsurgery syndrome, spinal stenosis, and disc herniation [1‐8]. Disc herniation and spinal stenosis are often managed with surgical interventions and postsurgery syndrome may also be managed with repeat surgical interventions or implantable therapies. However, for those patients who are not responsive to or candidates for surgical interventions and/or have not adequately responded to epidural injections, percutaneous adhesiolysis may be an option [1‐12]. Percutaneous adhesiolysis is also considered an option in patients not amenable to or having an inadequate response to neuromodulation therapies [1, 7‐16]. Changing coverage policies have impacted utilization patterns of interventional techniques in general and percutaneous adhesiolysis in particular [1, 9‐16].

National health care expenditures are an important issue, specifically since the COVID-19 pandemic, which has drastically altered health care delivery and modes of treatment [17‐33]. The COVID-19 pandemic and the opioid epidemic have negatively impacted access to treatment and costs in chronic pain sufferers [17‐33]. The analysis of national health care spending in the USA showed an increase of 9.7% to reach $4.1 trillion in 2020, compared with a 4.3% increase seen in 2019 [17, 18]. The acceleration in 2020 was related to a 36% increase in federal expenditures for health care that occurred largely in response to the COVID-19 pandemic. Multiple other factors, including consolidation of providers into an employment model by health systems, which has increased substantially, has been contributing to increasing health care expenses [17, 18, 23‐36]. Multiple effects due to COVID-19, with increased psychological stress and suffering, may also have a significant effect on outcomes [27, 30‐32]. An analysis of the utilization patterns in the fee-for-service (FFS) Medicare population, including the impact of COVID-19, showed declining interventional techniques with an overall decrease of interventional techniques at an annual rate of 0.4% per 100,000 Medicare population from 2010 to 2019, and a decrease of 24.5% for epidural injections and adhesiolysis procedures [19]. However, the decrease from 2019 to 2020 due to the COVID-19 pandemic was 18.7% for all interventions compared with 19.0% for epidural and adhesiolysis procedures [19]. Additionally, epidural-specific utilization patterns [22] showed an overall decrease of utilization of epidural injections of 24.1% annually from 2010 to 2019, with a significant effect of the COVID-19 pandemic showing a 19.0% decrease from 2019 to 2020 [22]. Further, compared with multiple other interventions, including epidural injections, facet joint interventions, and sacroiliac joint interventions, augmentation procedures [10, 11, 14‐16] and percutaneous adhesiolysis [12] have faced a substantial decline at a rapid rate. There is discordance of opinions on the efficacy and effectiveness of medical necessity and indications among various authorities [1‐8].

Helm et al. [6] published a systematic review of percutaneous adhesiolysis in 2016 utilizing seven randomized controlled trials (RCTs) and three observational studies, concluding with level I or strong evidence of the efficacy of percutaneous adhesiolysis in the treatment of chronic refractory low back and lower extremity pain. In subsequent reports, Cho et al. [7] and Manchikanti et al. [2‐4] have shown level II–I evidence for post lumbar surgery syndrome, spinal stenosis, and disc herniation. In fact, Cho et al. [7] have shown significant evidence for both percutaneous adhesiolysis and spinal cord stimulation (SCS) with a recommendation of level A for epidural adhesiolysis for 6–12 months of pain relief and functional improvement and level B for SCS.

In contrast, Brito-García et al. [8] in a systematic review without meta-analysis provided a rather poor methodological quality assessment of the rating of the trials, with downgrading to low quality, which have been rated as high quality in multiple other evaluations. Overall, they concluded that there was no evidence for percutaneous adhesiolysis. Thus, of the five systematic reviews, three of them, including a meta-analysis and one systematic review without meta-analysis, showed positive results compared with only one systematic review that, although it looked at similar studies, concluded very differently. Manchikanti et al. [5], in assessing systematic reviews with a systematic analysis, identified multiple issues in one of the systematic reviews. Further, Manchikanti et al. [1, 9, 37‐40] and others [41, 42] have also described extensively the issues related to performance of evidence synthesis in systematic reviews and meta-analysis.

Consequently, to assess the efficacy of percutaneous adhesiolysis in managing low back and lower extremity pain this systematic review and meta-analysis of RCTs was undertaken..

A systematic review and meta-analysis were performed based on the methodological and reporting quality of systematic reviews, as described by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) [43]. Methodology from other reviews was also utilized [2‐5, 37‐39, 44].

The present systematic review and meta-analysis of percutaneous adhesiolysis for low back and lower extremity pain secondary to postsurgery syndrome, central spinal stenosis, and chronic disc herniation showed level I–II or strong to moderate evidence with nine relevant RCTs with moderate to strong strength of recommendation. The RCTs were from six trials studying postsurgery syndrome, two trials studying spinal stenosis, and one randomized placebo-controlled trial studying disc herniation. All other trials were active controlled. Past analysis of evidence synthesis based on individual conditions showed level I evidence for postsurgery syndrome [1, 3, 5, 6] and level II evidence for central spinal stenosis [1, 2] and chronic disc herniation [1, 3]. In contrast to previous reviews, the present meta-analysis combines all updates with utilization of all nine RCTs for three conditions [1‐4].

Failed back surgery syndrome (FBSS) was defined by the International Association for the Study of Pain (IASP) as a phenomenon of persistent or recurrent pain, mainly in the lower back or legs, even after previously anatomically successful surgeries [77]. FBSS has been described extensively [72, 78‐82]. The most common causes of FBSS have been identified as epidural fibrosis, arachnoiditis, recurrent disc herniation, and lateral and central spinal stenosis. Spinal stenosis is the result of abnormal narrowing of the spinal canal, lateral recess, or the intervertebral foramina, resulting in pressure on the spinal cord and/or nerve roots [83‐86].

Among the studies that met the inclusion criteria, seven trials provided 1 year results and all of them reported positive results. However, at 6 months follow-up of the nine trials, one trial reported negative results [61]. The one negative trial [61] essentially compared percutaneous adhesiolysis with an inflatable balloon catheter. The inflatable balloon catheter had better results.

The results of this systematic review are in agreement with the majority of previous studies [1‐7], except for one notable exception [5, 8]. The systematic review performed by Brito-García et al. [8] did not include a meta-analysis. Since the publication of the Brito-García review [8], other RCTs have been published. While multiple systematic reviews showed positive evidence ranging from level I to II [1‐6], Cho et al. [7] showed a higher level of evidence for adhesiolysis than SCS.

Systematic reviews and meta-analysis are performed to meet the goals of evidence-based medicine using the best available evidence in determining clinical care for an individual patient or population. While systematic reviews and meta-analyses are expected to provide information from high-quality research, they may vary and do not guarantee high methodological and reporting rigor [39]. In the scientific world, multiple biases may be present, with publication bias, outcome reporting bias, multiple publication bias, place of publication bias, citation bias, and interpretation bias, which appear to be crucial and relevant to systematic reviews in interventional pain management [39]. Of importance is the interpretation bias referring to the researchers’ or reviewers’ abilities to synthesize and objectively judge and weigh the results found in a study. Consequently, two researchers of different backgrounds might look at the same result in a different way, thus drawing different conclusions based on their own background [87‐89]. This is common when the data are debatable or qualitative, leading to some conclusions being overstated while others are understated [89]. The major issue is the erroneous classification of trials as “pragmatic” and “real world”. Dal-Ré et al. [50] described that a genuinely pragmatic RCT should fulfill at least two fundamental features, including conduct of the study, which should resemble usual clinical practice, and the applicability of the results to multiple other settings, i.e., real world, not only the one where the trial was conducted. They also showed that some RCTs overtly deviate from usual clinical care and pragmatism, yet many RCTs are classified as pragmatic for purposes of convenience since pragmatic trials are set to represent real-world evidence. A recent publication of epidural steroids in disc herniation and sciatica in response to Cochrane review [90] illustrated multiples of these issues [38, 39]. Further, the role of placebo also has been a seeming source of continuous debate and has been the cause of discordance [40]. In fact, Manchikanti et al. [5] performed a systematic analysis of findings of systematic reviews in post lumbar surgery syndrome showing high compliance in only one systematic review [6] and moderate compliance with two systematic reviews [3, 7], whereas, one systematic review showed negative results with low compliance rate [8] with the PRISMA checklist. A Measurement Tool to Assess Systematic Reviews (AMSTAR) scoring also showed similar results, with high compliance for three systematic reviews [3, 6, 7] and poor compliance for one systematic review [8]. They also evaluated with Scottish Intercollegiate Guidelines Network (SIGN) scoring system showing similar results, thus one systematic review [8] consistently showed lower methodological quality. The present systematic review showed that all the trials included resembled clinical practice, with applicability of the results in a real-world setting.

Epidural steroid injections have been used extensively in managing low back and lower extremity pain [1, 10‐16, 19, 22, 37‐39, 91, 92]. Causes of chronic radicular pain include mechanical compression of nerve roots, as well as different proinflammatory substances [1] that trigger ectopic neuron firing [1]. Chronic radicular pain secondary to postsurgery syndrome, central spinal stenosis, and disc herniation are managed with mechanical decompression around the compressed nerve root, and inhibition of the inflammatory mediators by injecting targeted steroids into the epidural space or around the affected nerve. While results of studies of epidural injections continue to be debated and differ, the proportion of patients who failed to respond to epidural steroid injections are candidates for percutaneous epidural adhesiolysis [1, 42, 91, 92]. Thus far, the evidence has been in favor of percutaneous adhesiolysis in managing post lumbar surgery syndrome, spinal stenosis, and chronic disc herniation [1‐6]. The mechanism described in percutaneous adhesiolysis is the combined effect of local lavage of proinflammatory cytokines, reduction of swelling, lysis of adhesions, desensitization and modification of neuromodulation, and local anesthesia. The presence of epidural adhesions may be diagnosed with magnetic resonance imaging (MRI), followed by epidurography based on filling defects. These filling defects by epidurography are minimized in size after successfully performing epidural lysis of adhesions. The epidural space is opened by injection of solutions if the catheter is placed directly into the zone of adhesions. However, the mechanical effect of adhesiolysis with a catheter has been debated [83]. It has been shown that the catheter itself was not able to have a significant mechanical effect in an experimental study setup. However, the authors themselves discussed the obvious limitations that the experimental setup did not represent the real clinical and anatomical environment. However, based on extensive clinical experience, we believe that the mechanical effects are real.

The limitations of this systematic review include the continued paucity of literature despite nine eligible trials that looked at various conditions separately (i.e., postsurgery syndrome, central spinal stenosis, and disc herniation). The other limitation is the lack of placebo-controlled trials despite significant differences noted among the active-controlled trials utilizing epidural injection as control.

This systematic review with meta-analysis utilizing appropriate methodology with qualitative and quantitative evidence synthesis with conventional dual- and single-arm analyses shows level II–I, or moderate to strong evidence of effectiveness based on five high-quality and two moderate-quality RCTs with 1 year follow-up, showing improvement in pain and function as well as a decrease in opioid consumption.