SUMMARY
PLSS has been reported with increasing frequency, simultaneously with increased surgical volume (Weinstein et al., 2006; Deyo et al., 2009). Consequently, health care expenditures have been increasing substantially over the years with an increase of interventional techniques performed to manage various types of low back pain including the pain resulting from PLSS (Lieberman 2004; Manchikanti et al., 2009).
The continued pain and disability in the low back and lower extremities following lumbar spine surgery has been hypothesized to be secondary to multiple causes including epidural fibrosis, acquired stenosis, sacroiliac joint pain, and facet joint pain (Fritsch et al., 1996; Manchikanti et al., 2009B).
Patients with PLSS usually have a long-standing history of pain. As pain persists, psychological influence and environmental factors assume more significant role in disability, perhaps exacerbating and maintaining pain. (Chan and Peng, 2011).
Interdisciplinary assessment and care is now the cornerstone of the treatment of many chronic pain conditions. So, the general management plan should not focus solely on medical therapy. The objectives of management should be directed to restoration of functional ability, improvement of quality of life, coping strategies, and pain self-management (Manchikanti et al., 2009C; McCracken and Turk, 2002).
To achieve these goals, various aspect of CBT should be emphasized in addition to medical and surgical therapies to address the multiple etiologies that may be present (Chan and Peng, 2011).
Evidence-based guidelines on low back pain management have recently been published to aid treating clinicians (Chou et al., 2009).
The nature of therapies may be divided into conservative (pharmacological, physical, and cognitive–behavioral and rehabilitative), interventional (facet medial branch blocks and rhizotomy; sacroiliac joint blockade; epidural steroids and percutaneous epidural adhesiolysis), and surgical (spinal cord stimulation; intrathecal drug delivery systems and revision surgery) (Chan and Peng, 2011).
Trials specifically examining the response to therapies in PLSS are less prevalent than those for CLBP. Due to the difficulty in treating some patients with PLSS and their associated disability, physicians have looked to more radical modes of therapy to reduce pain and improve functional capacity and quality of life in these patients (Chan and Peng 2011).
Whereas in the past, there were very few trials looking at the efficacy of these modalities, the past 5 years has witnessed the completion of several trials and meta-analyses addressing the success of various interventions in treating PLSS (Chan and Peng, 2011).
- Epidural Injections:
The placement of steroids in the epidural space to relieve radicular pain of spinal origin has been a long used method in pain medicine. The evidence for inter-laminar epidural steroids in lumbar radicular pain is strong for short-term relief and limited for long-term benefit (Abdi et al., 2007).
The evidence for caudal epidural steroid injections was strong for short-term relief and moderate for long-term relief in chronic lumbar radicular pain and radicular pain associated with PLSS. The evidence for transforaminal epidural steroid injections for lumbar nerve root pain was strong for both short-term and long-term improvement (Abdi et al., 2007).
The exact mechanism by which epidural corticosteroids exert their analgesic effect remained to be fully elucidated. The proposed mechanisms include an anti-inflammatory effect (Lee et al., 1998), reducing vascular permeability (Byrod et al., 2000), and sodium channel blockade (Manchikanti, 2007).
Epidural steroids are effective for epidural fibrosis, disc disruption, disc herniation, and spinal stenosis. Therefore, epidural steroids may address several of the pathologies associated with the development of PLSS (Manchikanti et al., 2008D).
Studies evaluating the effectiveness of fluoroscopically directed caudal epidural injections under optimal conditions of contemporary interventional pain management practice in a large number of patients are lacking (Manchikanti et al., 2012).
In a systematic review by Conn et al of randomized and nonrandomized studies of caudal epidural injections for managing chronic low back pain of PLSS along with other conditions, only one trial’s preliminary data (Manchikanti et al., 2008D) met inclusion criteria of long-term follow-up of at least 6 months along with the use of fluoroscopic visualization. They concluded that due to the paucity of literature, the evidence was Level II-2 (Conn et al, 2009).
However, other systematic reviews have combined multiple approaches into one category, with the majority of them performed blindly without fluoroscopy (Staal et al., 2009).
There are important anatomical differences between patients with PLSS and those with CLBP who have not undergone surgery. The presence of epidural fibrosis, instrumentation, and anatomical alteration in the PLSS spine increases the difficulty of depositing corticosteroid accurately in the epidural space and the risk of dural puncture, with rates as high as 20% (Fredman et al., 1999; Rowlingson, 1999).
Therefore, most authors recommend the use of fluoroscopic guidance and a caudal approach to overcome these factors (Fredman et al., 1999; Rowlingson, 1999; Manchikanti et al., 2004B; Manchikanti et al., 2008D).
Even with correct radiographic placement, studies have demonstrated that the injection of steroids via the caudal route may still not ensure that steroid will reach the desired site (Manchikanti et al., 2004B).
A more recent randomized, active control, double-blind trial compared the effectiveness of fluoroscopically directed caudal epidural injections of local anesthetic alone with local anesthetic combined with steroid in managing chronic low back and lower extremity pain secondary to PLSS, Giving clinically meaningful and significant results, as it was performed on relatively large number of patients (140 patients) (Manchikanti et al., 2012).
The results of this practical evaluation performed in a nonacademic private practice setting simulating practice patterns illustrates that in carefully selected patients, who do not have facet joint pain, those judged as successful participants (i.e., who responded to the first 2 procedures with at least 3 weeks of relief). Further, the overall improvement was also significant when all participants were included (Manchikanti et al., 2012).
Thus, this study confirms that caudal epidural injections in appropriately selected patients with PLSS are a successful modality for managing this chronic, recalcitrant condition (Manchikanti et al., 2012).
Further, the response was similar in patients receiving local anesthetic only or local anesthetic and steroid combination with nonparticulate betamethasone. There was no significant difference in the total relief over a period of 2 years. Further, the average relief per procedure for the initial 2 procedures, as well as subsequent procedures and overall procedures over the period of 2 years was similar in both groups of patients with respect to overall results (Manchikanti et al., 2012).
The average number of procedures at the end of one year was approximately 3.5 and after 2 years, the average number was 5 in both groups. However, in the successful groups, the number of treatments was approximately 4 and 6 at the end of one and 2 years (Manchikanti et al., 2012).
In a study involving inter-laminar epidural at the site of interest and passage of a catheter, contrast injection demonstrated that the steroid solution may only reach the site of interest in 26% of cases (Fredman et al., 1999).
An alternative approach to the epidural space is through the transforaminal route. While this approach is efficacious in patients who have not received prior lumbar spine surgery, the success rates in patients with PLSS were low. Only 27% of the treated patients had >50% reduction in pain scores at 6 months follow-up (Devulder et al., 1999).
- Percutaneous Epidural Adhesiolysis:
Epidural fibrosis is a common occurrence after spinal surgery. Some researchers state that epidural fibrosis may be the culprit in as many as 36% of cases of PLSS (Fritsch et al., 1996; Kayaoglu et al., 2003).
Furthermore, fibrosis may inhibit the passage of regional medication to areas of spinal pathology responsible for pain (Manchikanti et al., 2008D).
Epidural scarring can arise from a number of causes, most obviously surgery, infection, or hematoma, but also because of disc herniation or simply the cumulative effect of recurrent subclinical bleeding as the rich plexus of veins in the epidural space suffer small tears during the slow process of degeneration that occurs with aging (Helm et al., 2012).
At this point, it is accepted that scarring can cause pain, whether by tethering nerve roots so that they are placed under tension with movement or by decreasing nutrition to the roots either by direct compression or compression of adjacent veins. Furthermore, compression, degeneration, or leakage of nuclear material can lead to an inflammatory response, with pain (Helm et al., 2012).
Percutaneous epidural adhesiolysis is a procedure designed to lyse epidural scarring in patients with persistent low back and leg pain due to PLSS or spinal stenosis (Helm et al., 2012).
It aims to reduce epidural fibrotic tissue and improve the delivery of epidurally administered drugs to their target tissue (e.g., nerve roots) (Heavner et al., 1999; Racz et al., 1999; Trescot et al., 2007).
The incidence of complications from percutaneous adhesiolysis is low and the complications are generally minimal and self-limited. The procedure should be considered to be low risk for serious adverse events when performed by well-trained physicians (Helm et al., 2012).
A recently published systematic review to address the efficacy of percutaneous adhesiolysis for PLSS, in patients who failed conservative management including fluoroscopically directed epidural steroid injections, found that strong evidence exists for short- and long-term pain relief with the use of this intervention. Long-term relief was defined as efficacy longer than 6 months. (Epter et al., 2009).
The superiority of adhesiolysis over epidural steroid injections is hypothesized to result from the placement of the catheter tip within the fibrosis and expanding the perineural space. Once opened, the medication including steroids may then reach the appropriate lesion site and provide neural blockade and anti-inflammatory effect (Epter et al., 2009).
Adhesiolysis is best reserved for PLSS patients experiencing radicular pain who have failed conservative measures including epidural steroid trials. However, future studies to determine if percutaneous adhesiolysis performed earlier is associated with improved outcome would be valuable (Epter et al., 2009).
More recently, a systematic review was done by Helm et al. to reassess all the literature on adhesiolysis up to June 2012, including new literature since the last review, focusing on both PLSS and on spinal stenosis (Helm et al., 2012).
Of these recent literatures, a high quality RCT (Manchikanti et al., 2009F) included 120 patients with chronic function limiting pain with PLSS. The sample size is adequate in this extremely difficult population with a history of PLSS and failure of all types of conservative management. This study includes one year follow-up which is the largest of any of the studies conducted thus far (Helm et al., 2012).
Results showed significant pain relief in 73% of the patients and functional improvement in 77% undergoing adhesiolysis at one-year follow-up. Significant differences were observed between control group and adhesiolysis group. In the control group significant relief was observed in 12% of patients with functional improvement in 13% of patients at one-year follow-up (Manchikanti et al., 2009F).
This RCT, as a practical clinical trial, or an equivalence trial, provides generalizability and external validity better than a placebo-controlled trial (Manchikanti et al., 2009F; Helm et al., 2012).
The cost effectiveness of this intervention also has been demonstrated showing that this procedure is safer and more cost effective than surgery, spinal cord stimulation, intrathecal implantables, or conservative medical management (Manchikanti et al., 2009F).
The results of this RCT are similar to the previous RCTs reviewed by Epter et al., 2009 (Manchikanti et al., 2009F).
Applying the United States Preventive Services Task Force (USPSTF) criteria (Berg and Allan, 2001), Helm et al., 2012 indicate that there is fair evidence that percutaneous adhesiolysis is effective in relieving low back and/or leg pain caused by PLSS (Helm et al., 2012).
The procedure does not provide permanent relief, but, repeated up to 3 to 4 times year, provides relief in patients who have no other option to find relief other than implantable devices or the unlikely benefit of further surgery (Helm et al., 2012).
The common factor which differentiates percutaneous adhesiolysis from an epidural steroid injection, whether done through a needle or using a non-wire bound catheter, is the use of a wire-bound, steerable catheter to deliver appropriate volumes of saline, steroid, and local anesthetic into the target area (Helm et al., 2012).
Percutaneous adhesiolysis involves multiple components of treatment with adhesiolysis, injection of local anesthetic, steroid, and hypertonic sodium chloride solution (Helm et al., 2012).
There has been varying evidence for all the drugs utilized despite its targeted delivery (Manchikanti et al, 2004C).
Furthermore, all the drugs have varying mechanisms and results in managing chronic, persistent, recalcitrant pain occurring in PLSS (Helm et al., 2012).
Helm et al., 2012 indicate that the results of their systematic review may be applied in interventional pain management practices utilizing appropriate evaluations (Helm et al., 2012).
They conclude that this systematic review provides practical evidence for the management of an extremely difficult problem with recalcitrant low back and lower extremity pain either secondary to post surgery syndrome or spinal stenosis with a modality which is considered as safe with moderate results (Helm et al., 2012).