The Correlation of Epidural Fibrosis with Epiduroscopic and Radiologic Imaging for Chronic Pain after Back Surgery

BACKGROUND

Chronic low back pain is observed frequently after lumbar spinal surgery. Epidural fibrosis has been implicated in the etiology of persistent pain after back surgery. The incidence of epidural fibrosis increases as the number and extent of spinal surgery increases. Epidural fibrosis can be detected by conventional radiologic methods [e.g., lumbosacral magnetic resonance imaging (MRI) with gadolinium], but these methods are insufficient to reveal the presence of epidural adhesions. Imaging of the epidural cavity using an epiduroscope is one of the best methods for visualizing the spinal cavity without damaging anatomic structures.

OBJECTIVES

To evaluate the correlation between the type and number of surgery and the degree of epidural fibrosis and to compare epidural fibrosis in epiduroscopic and MRI findings in patients with failed back surgery syndrome (FBSS).

STUDY DESIGN

A prospective trial.

SETTING

A university hospital.

METHODS

This study included 61 patients with persistent low back pain and/or radicular pain for at least 6 months, despite lumbar surgery and conservative treatment, and who accepted epiduroscopic imaging. All patients were evaluated in a physical examination using a visual analog scale (VAS) per the elapsed time after surgery. The patients were divided into 3 groups according to the number and type of surgeries. Epidural fibrosis was rated using MRI with gadolinium and epiduroscopy.

RESULTS

When the relationship between admission symptoms and epidural fibrosis was evaluated, MRI findings of fibrosis were found to be significantly higher in all patients with both lumbar and radicular pain symptoms at the confidence level of 95% (P = 0.001). The degree of fibrosis detected using epiduroscopy was grade 1 and 2 in almost all patients who presented with low back pain only, only radicular pain, or only distal paresthesia (P = 0.001). In the correlation analysis between the duration of the postoperative period (4.13 ± 2.97 years) and the degree of fibrosis detected using MRI and epiduroscopy, a statistically significant relationship was found at the confidence level of 95% (P < 0.05). As the number and extent of spinal surgeries increased, the incidence of MRI fibrosis increased, which is compatible with the literature (P = 0.001) There was a statistically significant relationship between the degree of fibrosis as detected using MRI and epiduroscopy at the confidence level of 95% (P < 0.05). Differently, we observed that 6 patients had grade 1 fibrosis as diagnosed using epiduroscopy, whereas none had fibrosis on MRI.

LIMITATIONS

We did not have a control group. Further studies are required to demonstrate the relevance of these 2 imaging techniques (epiduroscopy and MRI) in terms of detecting epidural fibrosis in patients with FBSS.  CONCLUSIONS: Epiduroscopic imaging seems to be more sensitive than MRI in detecting grade I epidural fibrosis in patients with FBSS. Thus, the possibility of low-grade epidural fibrosis as a source of pain after back surgery, should be kept in mind in normally reported MRIs. Treatment should be planned accordingly.

Neuromodulation for chronic pain

Neuromodulation is an expanding area of pain medicine that incorporates an array of non-invasive, minimally invasive, and surgical electrical therapies. In this Series paper, we focus on spinal cord stimulation (SCS) therapies discussed within the framework of other invasive, minimally invasive, and non-invasive neuromodulation therapies. These therapies include deep brain and motor cortex stimulation, peripheral nerve stimulation, and the non-invasive treatments of repetitive transcranial magnetic stimulation, transcranial direct current stimulation, and transcutaneous electrical nerve stimulation. SCS methods with electrical variables that differ from traditional SCS have been approved. Although methods devoid of paraesthesias (eg, high frequency) should theoretically allow for placebo-controlled trials, few have been done. There is low-to-moderate quality evidence that SCS is superior to reoperation or conventional medical management for failed back surgery syndrome, and conflicting evidence as to the superiority of traditional SCS over sham stimulation or between different SCS modalities. Peripheral nerve stimulation technologies have also undergone rapid development and become less invasive, including many that are placed percutaneously. There is low-to-moderate quality evidence that peripheral nerve stimulation is effective for neuropathic pain in an extremity, low quality evidence that it is effective for back pain with or without leg pain, and conflicting evidence that it can prevent migraines. In the USA and many areas in Europe, deep brain and motor cortex stimulation are not approved for chronic pain, but are used off-label for refractory cases. Overall, there is mixed evidence supporting brain stimulation, with most sham-controlled trials yielding negative findings. Regarding non-invasive modalities, there is moderate quality evidence that repetitive transcranial magnetic stimulation does not provide meaningful benefit for chronic pain in general, but conflicting evidence regarding pain relief for neuropathic pain and headaches. For transcranial direct current stimulation, there is low-quality evidence supporting its benefit for chronic pain, but conflicting evidence regarding a small treatment effect for neuropathic pain and headaches. For transcutaneous electrical nerve stimulation, there is low-quality evidence that it is superior to sham or no treatment for neuropathic pain, but conflicting evidence for non-neuropathic pain. Future research should focus on better evaluating the short-term and long-term effectiveness of all neuromodulation modalities and whether they decrease health-care use, and on refining selection criteria and treatment variables.

Celecoxib-Loaded Electrospun Fibrous Antiadhesion Membranes Reduce COX-2/PGE2 Induced Inflammation and Epidural Fibrosis in a Rat Failed Back Surgery Syndrome Model

To date, failed back surgery syndrome (FBSS) remains a therapy-refractory clinical condition after spinal surgery. The antiadhesion membrane is applied to prevent FBSS by isolating fibrosis; however, the inflammation stimulated by the foreign body and surgical trauma needs to be further resolved simultaneously. Therefore, we developed new electrospun polycaprolactone (PCL) fibrous membranes loaded with celecoxib (CEL) to prevent fibrosis and inflammation associated with FBSS. The CEL-loaded PCL fibers were randomly distributed, and the drug was released over two weeks. Fluorescence micrographs revealed that the fibroblasts proliferated less on the PCL-CEL fibrous membranes than in the PCL group and the blank control. In the rat laminectomy model after 4 weeks, magnetic resonance imaging of epidural fibrosis was least in the PCL-CEL group. Expression of COX-2 and PGE2 was lower in the PCL-CEL group. It concluded that the CEL-loaded PCL membrane could reduce fibrosis and inflammation in a rat model of FBSS via COX-2/PGE2 signaling pathways.

An Evidence Based Review of Epidurolysis for the Management of Epidural Adhesions

PURPOSE OF REVIEW

This review presents epidurolysis as a procedure to alleviate pain and disability from epidural adhesions. It reviews novel and groundbreaking evidence, describing the background, indications, benefits and adverse events from this procedure in an effort to provide healthcare experts with the data required to decide on an intervention for their patients.

RECENT FINDINGS

Epidural adhesions (EA) or epidural fibrosis (EF) is defined as non-physiologic scar formation secondary to a local inflammatory reaction provoked by tissue trauma in the epidural space. Often, it is a sequelae of surgical spine intervention or instrumentation. The cost associated with chronic post-operative back pain has been reported to be up to nearly $12,500 dollars per year; this, coupled with the increasing prevalence of chronic lower back pain and the subsequent increase in surgical management of back pain, renders EF a significant cost and morbidity in the U.S. Though risk factors leading to the development of EA are not well established, epidural fibrosis has been reported to be the culprit in up to 46% of cases of Failed Back Surgery Syndrome (FBSS), a chronic pain condition found in up to 20-54% of patients who receive back surgery. Moreover, EF has also been associated with lumbar radiculopathy after lumbar disc surgery. Epidurolysis is defined as the mechanical dissolution of epidural fibrotic scar tissue for persistent axial spine or radicular pain due to epidural fibrosis that is refractory to conservative therapy Endoscopic lysis of adhesions is a procedural technique which has been shown to improve chronic back pain in one-third to one-half of patients with clinically symptomatic fibrous adhesions. Here we review some of the novel evidence that supports this procedure in EA and FBSS.

SUMMARY

The literature concerning epidurolysis in the management of epidural adhesions is insufficient. Prospective studies, including randomized controlled trials and observational studies, have suggested epidurolysis to be effective in terms of pain reduction, functional improvement, and patient satisfaction scores. Observational studies report epidurolysis as a well-tolerated, safe procedure. Current evidence suggests that epidurolysis may be used as an effective treatment modality for epidural adhesions. Nonetheless, further high quality randomized controlled studies assessing the safety and efficacy of epidurolysis in the management of epidural adhesions is needed.

Transforaminal Epiduroscopy in Patients with Failed Back Surgery Syndrome

BACKGROUND

Epiduroscopy is a useful diagnostic and therapeutic tool for managing failed back surgery syndrome (FBSS). The conventional approach is via either the sacral hiatus or the interlaminar. Major causes of FBSS include epidural fibrosis, disc herniation, and stenosis. When these problems are located at the intervertebral foramen level, it can be difficult to reach the lateral recess and the foramen with the epiduroscope. Transforaminal epiduroscopy could be a useful alternative approach in patients with FBSS located at the foraminal level.

OBJECTIVE

We present a new procedure for lumbar epiduroscopy via a transforaminal approach and its application in patients with FBSS. The technique is described and long-term results are reported.

STUDY DESIGN

This study used a single-arm prospective observational design.

SETTING

The research took place at the University Hospital in Spain.

METHODS

Patients with FBSS suffering severe chronic radicular pain (Numeric Rating Scale [NRS-11] > 7) who had not responded to other treatments were included. Selective root stimulation during a pulsed radiofrequency procedure confirmed the origin of pain by means of an exact reproduction of typical pain. Transforaminal epiduroscopy was performed at the affected level. The severity of fibrosis observed was recorded. The NRS-11 score was reevaluated at 1, 6, and 12 months after the procedure. Any complications related to the treatment were recorded.

RESULTS

Twenty-four patients were included. The mean number of back surgeries was 1.66 (range, 1-5). The basal NRS-11 score was 7.83 (0.14); at 1 month, 3.66 (0.38) (P < 0.001); at 6 months, 4.46 (0.48) (P < 0.01); and at 1 year after treatment, 4.17 (0.51) (P < 0.01). Most patients (54%; 95% CI, 34%-74%) obtained > 50% pain reduction on the NRS-11, maintained during a 1-year follow-up period. No major complications were registered.

LIMITATIONS

The research was limited by the lack of a control group.

CONCLUSIONS

We have described a new procedure for epiduroscopy via the transforaminal approach. It is a useful and safe approach to managing FBSS at the foraminal level and shows better long-term results than other endoscopic procedures.

KEY WORDS

Epidural, epiduroscopy, chronic pain, spinal cord, back surgery.

New insights from immunohistochemistry for the characterization of epidural scar tissue

BACKGROUND

The association between epidural fibrosis and recurrent symptoms after lumbar spine surgery remains a matter of debate in scientific literature and the underlying pathophysiological mechanism has not been clearly elucidated.

OBJECTIVE

To investigate the presence of nerve fibers and the expression of osteopontin in epidural fibrous tissue after lumbar surgery in humans.

STUDY DESIGN

Laboratory study of human tissue samples.

METHODS

Twenty-four patients with persistent or recurrent low back and/or leg pain after lumbar spine surgery, in whom no relevant findings were present on magnetic resonance imaging (MRI) besides epidural scar tissue, were submitted to epiduroscopy. Biopsy samples of epidural scar tissue resting in the posterior epidural and periradicular space were obtained from 15 patients, using an endoscopic grasping forceps, in locations where the stimulation with the tip of a Fogarty consistently reproduced pain. Biopsy samples were processed for examination under optical and transmission electron microscopes and under a fluorescence microscope after incubation in primary antibodies against beta3-tubulin or against osteopontin.

RESULTS

Optical and transmission electron microscopy revealed a homogeneous fibrous tissue rich in collagen and lacking nerve fibers. No immunofluorescence was present in any of the samples immunoreacted against beta3-tubulin. In the samples immunoreacted against osteopontin, a punctate signal was detected around the collagen fibers.

LIMITATIONS

Being a human study, there was no control group, so it is not possible to determine the contribution of osteopontin in the formation of epidural fibrosis and its relation to the patients' symptoms. Additional animal studies are needed to investigate these issues.

CONCLUSION

Rather than direct stimulation of nociceptors in the epidural scar tissue, other factors should relate epidural fibrosis and recurrent symptoms after lumbar spine surgery. Osteopontin seems to play a role in the formation of epidural fibrosis.

Epidural adhesiolysis: an evidence-based review

First described over 25 years ago, epidural lysis of adhesions (LOA) involves the mechanical dissolution of epidural scar tissue, which may directly alleviate pain and facilitate the spread of analgesic substances to area(s) of pain generation. Although it most commonly performed for lumbar failed back surgery syndrome, there is a growing body of evidence that suggests it may be effective for spinal stenosis and radicular pain stemming from a herniated disc. There is weak positive evidence that LOA is more effective than conventional caudal epidural steroid injections for failed back surgery syndrome and spinal stenosis, and that LOA is more effective than sham adhesiolysis and conservative management for lumbosacral radiculopathy. For cervical disc herniation and spinal stenosis, there is only anecdotal evidence suggesting effectiveness and safety. Factors that may contribute to the enhanced efficacy compared to traditional epidural steroid administration include the high volume administered, the use of hypertonic saline, and to a lesser extent the use of hyaluronidase and a navigable catheter to mechanically disrupt scar tissue and guide medication administration. Although LOA is widely considered a safe intervention, the complication rates are higher than for conventional epidural steroid injection.

Prevention of scar tissue formation in spinal surgery: state of the art and review of the literature

Recurrent radicular pain after lumbar micro-discectomy may lead to reduced quality of life of the patient. Lumbar epidural fibrosis is believed to be one of the mechanisms involved in the genesis of the pain. The use of absorbable gel temporarily separating disc remnants, muscle or bone structures from the nerve roots could reduce the amount of scar tissue surrounding the nerve, reduce tethering and therefore pain, improve outcomes and facilitate revision surgery. The author reviews the literature on prevention techniques for lumbar epidural fibrosis. The most recent studies on new compounds are encouraging in terms of safety and clinical efficacy.

Effect of cepea extract-heparin and allantoin mixture on epidural fibrosis in a rat hemilaminectomy model

AIM

Epidural fibrosis following a laminectomy procedure is a serious problem that results in failed back surgery syndrome. Aserious number of manuscripts have explained its possible mechanism and results but no effective preventive surgical technique or treatment is currently present.

MATERIAL AND METHODS

We used a rat hemilaminectomy model at lumbar fourth level. In the treatment group (n:10), the hemilaminectomy sites were filled with cepea extract-allantoin and heparin mixture as sterile cream form. In the second group, the same surgical procedure was performed and the site was filled with physiological saline. All animals were terminated after 6 weeks and laminectomy sites removed en-bloc. Epidural fibrosis was evaluated and compared using semi-quantitative histopathological scoring scales.

RESULTS

In the physiological saline group, the fibrosis score was 10.3 points and 90% of the subjects had acute inflammatory reaction, 80% chronic inflammatory reaction and 100% showed bone destruction and reparation process. In the cepea extract group, these values were fibrosis score 4.2 points, 0% acute inflammatory reaction, 33.3% chronic inflammatory reaction and 10% bone destruction and reparation process, respectively.

CONCLUSION

This study showed that aloe cepea extract-allantoin and heparin mixture diminished epidural scarring formation effectively with decreased scores of acute and chronic inflammation, compared to the physiological saline solution group.

Effectiveness of spinal endoscopic adhesiolysis in post lumbar surgery syndrome: a systematic review

BACKGROUND

Post lumbar surgery syndrome with persistent chronic low back and lower extremity pain is common in the United States. Epidural fibrosis may account for as much as 20% to 36% of all cases of failed back surgery syndrome (FBSS). Percutaneous adhesiolysis with a catheter or direct visualization of the spinal canal and the contents with an endoscope are techniques employed in resistant cases when patients fail to respond to conservative modalities of treatment, including fluoroscopically directed epidural injections. Some patients failing to respond to percutaneous adhesiolysis are candidates for spinal endoscopic adhesiolysis. However, literature evaluating the effectiveness of spinal endoscopic adhesiolysis is sparse and discussions continue about its effectiveness, utility, and complications.

STUDY DESIGN

A systematic review of the available literature.

OBJECTIVE

To evaluate the effectiveness and safety of spinal endoscopic adhesiolysis in the management of chronic low back and lower extremity pain in post surgical patients with chronic recalcitrant pain, non-responsive to conservative modalities of management and fluoroscopically directed epidural injections.

METHODS

A search of relevant resources (PubMed, EMBASE, and the Cochrane database) was accomplished and the resulting publications were examined based on the inclusion/exclusion criteria set forth. Randomized controlled trials and observational studies were included in the search. Two reviewers assessed the studies' methodologies and outcomes. Randomized clinical trials were assessed and scored based on the criteria established by the Cochrane methodological assessment criteria of randomized clinical trials and the observational studies were assessed and scored based on the Agency for Healthcare Research and Quality (AHRQ) criteria. Clinical relevance was evaluated utilizing Cochrane review criteria. Analysis was conducted using 5 levels of evidence, ranging from Level I to III, with 3 subcategories in Level II.

OUTCOME MEASURES

The primary outcome measure was pain relief (> or = 50%) in follow-up for at least 6 months. Pain relief for longer than 6 months was considered long-term and 6 months or less was considered short-term. The secondary outcome measures were functional and psychological status, return to work, patient satisfaction, and opioid intake.

RESULTS

Of the 13 studies considered for inclusion, one randomized trial and 5 observational studies met inclusion criteria for evidence synthesis based on the inclusion criteria and methodologic quality scores of 50 or more. The indicated level of evidence for endoscopic adhesiolysis is Level II-1 or II-2 evidence for short- and long-term relief based on the U.S. Preventive Services Task Force (USPSTF) criteria.

LIMITATIONS

There was a paucity of literature for randomized trials.

CONCLUSION

Spinal endoscopic adhesiolysis may be used as an effective treatment modality for chronic refractory low back pain and radiculopathy that is related to epidural adhesions.