Outcomes of Epidural Neuroplasty to Treat Lumbar Discogenic Pain- One-Year Follow-Up

Chinese J. Pain 2009;19(1):08~16 Outcomes of Epidural Neuroplasty to Treat Lumbar Discogenic Pain- One-Year Follow-Up 1,4 3 2 2 1,4 Li Wei, Kung-Shing Lee, Man-Kit Siu, Yu-Ting Tai, Jia-Wei Lin, 1,4 1,4 5,6 1,4 Kuo-Sheng Hung, Wen-Ta Chiu, I-JenWang, Tien-Jen Lin Background Epidural neuroplasty have emerged as minimally invasive techniques for treatment of low back pain and lower extremity pain due to contained herniated discs when conservative management has failed. A few studies have examined their effects on functional activity and pain medication use. Outcomes of the procedure to treat the ailment were not analyzed over time. Methods The aim of our study was to evaluate the outcome of epidural neuroplasty in patients with chronic discogenic pain or sciatica due to nerve root compression by a single-level, contained herniated disc. Patients were assessed before and 3, 6, and 12 months after treatment by a blinded investigator. In our retrospective, non-randomized case series, 26 patients with therapy of epidural neuroplasty were included. Patients were evaluated at 3, 6, and 12 months postoperatively, and were asked to quantify their pain using a visual analog scale. Patients were also surveyed in regards to their pain medication use, and Oswestry Disability Index (ODI) was quantified by third-party observers. Data at 3, 6, and 12 months posttreatment were compared to baseline. (Chinese J. Pain 2009;19(1): 08 ~ 16) Key Words: Discectomy, disc herniation, low back pain, minimally invasive, caudal neuroplasty and epidurolysis Results There was a significant decrease in pain and medication use reported in first three months after the treatment. Functional status also improved at the first 3 months. There were no complications associated with the procedure. Conclusion Epidural neuroplasty appear to be safe and significantly effective in either early post-treatment periods. Randomized, controlled studies are now required to further evaluate long-term efficacy of the combination therapy. 1 Department of Neurosurgery, Taipei Medical University, Wan Fang Hospital 2 Department of Anesthesiology, Taipei Medical University, Wan Fang Hospital 3 Department of Neurosurgery, Kaoshiung Medical University, Shiao Kang Municipal Hospital, 4 Injury Prevention and Control, Taipei Medical University ;Taiman, R.O.C 5 Taipei Hospital, Department of Health, Taipei 6 China Medical University, Taichung ; Taiwan, R.O.C. Address correspndence and reprint request to Tien-Jen Lin,MD,Msc Municipal Wan-Fang Hospital, Taipei Medical University, 111 Section 3, Hsin-Long Rd., Taipei 116, Taiwan TEL: +886-2-29307930 FAX: +886-2-27390387 E-mail: trlin@hotmail.com 08

Treating Lumbar Discogenic Pain Using Epidural Neuroplasty Introduction Kuslich et al (1) identified intervertebral discs, facet joints, ligaments, fascia, muscles and dura nearing nerve roots as tissues capable of transmitting pain in the low back. Discogenic pain, facet joint pain and sacroiliac joint pain have been proven to be common causes of pain with proven diagnostic techniques (2-5). Clinically, the intervertebral disc, can produce pain in the low back and lower extremities (1-3). Intervertebral disc-related pain can be caused by structural abnormalities, such as disc degeneration or disc herniation; correspondingly, biochemical effects, such as inflammation and neurobiological processes may play a role. First to create widespread interest in the disc as a source of pain in the American literature were Mixter and Barr (6) with their description of the herniated nucleus pulposus. Subsequent structural changes in the vertebral column suggested other contributing factors. In a review of the literature, Benzon (7) pointed out that abnormalities of the intervertebral disc include degeneration, bulging, and herniation. Narrowing of the disc space as a consequence of disc pathology is frequently associated with osteophyte formation, and osteoarthritis of the facet joints, which can put pressure on spinal nerves. Bulging of the intervertebral disc distends the posterior longitudinal ligament, causing localized back pain. If bulging of the disc increases, pressure may be exerted on the adjacent nerve roots, producing radicular pain. Mixter and Ayers (8) also demonstrated that radicular pain can occur without disc herniation. Internal disc disruption, or IDD, is a condition in which the internal architecture of the disc is disrupted but its external surface remains essentially normal (9). The general trend in spinal surgery, as in all surgical treatment, toward reduction of varieties of devices utilized and minimization of surgery-related trauma, led to the development of numerous minimally invasive percutaneous techniques for disc decompression and back pain management. Multiple percutaneously administered minimally invasive interventional techniques to achieve disc decompression have been described. Innervation of the ventral epidural space is extensive and, thus, may become highly sensitized, resulting in chronic low back pain. Histopathological studies have demonstrated extensive sinuvertebral nerve and sympathetic innervation over this confined space (10). Structures in the ventral epidural space may become highly sensitized by chemical irritation, resulting in axial pain. These structures include: 1. Ventral dura 2. Posterior longitudinal ligament 3. Vertebral periosteum 4. Dural attachments 5. Epi-radicular components. Chemical irritation is a major contributing factor in the origin of back pain with or without radiculopathy. The nucleus pulposus has been identified as a source of chemicals which, when leaked into the spinal canal via a lease in the annulus fibrosis, produce annoyance (11). Nerve roots were compressed by disc material often show signs of inflammation. Substances that might leak from the disc and produce inflammation of nerve roots or meninges include lactic acid, glycoprotein, cytokines, and histamine. In addition, it has been theorized that 09

Li Wei, Kung-Shing Lee, Man-Kit Siu, etal material from the nucleus pulposus might act as a foreign protein and trigger an autoimmune reaction. The identification of fibrosis as the origin of low back pain has never been debated. In patients who had undergone prior laminectomies, there was always some degree of peri-neural fibrosis. Although scar tissue itself was never tender, the nerve root was frequently very sensitive. Kuslich et al.(12) concluded that the presence of scar tissue compounded pain associated with the nerve root by fixing it in one position and thus increasing the susceptibility of the nerve root to tension or compression. Moreover, these researchers concluded compromising the nerve root. Local anesthetics, steroids, and normal saline are then injected through the catheter and the epidural catheter is removed. This procedure shows good results and is associated with only minor complications in a recent prospective randomized blinded clinical trial (14). Focusing on epidural neuroplasty seems to be one of the promising minimally invasive techniques for adhesion-lysis in patients with chronic sciatica with or without low back pain. At present, there are few studies supporting the longterm efficacy of neuroplasty for the treatment of chronic discogenic pain. Several studies have shown that, Sciatica can only be reproduced by direct that neuroplasty does effectively reduce pain in patients pressure or stretch on the inflamed, stretched, or compressed nerve root. No other tissues in the spine are capable of producing leg pain. Stolker and coworkers (13) challenged the idea that innervated structures are the only origins of pain. Mechanical factors are not the only causative factors of radicular pain. Histological injury may occur without compression, resulting in persistence of radicular symptoms. Nerve roots may be exposed to chemical irritant substances from degenerated intervertebral discs or facet joints, which can generate pain. Obviously, chemically induced irritation can occur in the absence of with contained herniated discs in six months (15,16). Only one study has examined the effect of neuroplasty on functional activity, pain relief, and pain medication use. However, this study did not analyze results over time (15,16). In the present report, outcomes of 26 nonrandomized patients treated with percutaneous disc decompression utilizing epidural neuroplasty were examined relative to the following parameters: reduction of pain over time, improvement in functional activity, and reduction of analgesic use longitudinally over 1 year in patients with radicular or axial low back pain secondary to contained herniated discs. compression by the disc. Epidural neuroplasty (mechanical lysis of epidural adhesions) is an interventional technique that was developed at Texas Tech Health Sciences Pain Center in 1989. It is indicated when conservative management for spinal or radicular pain has failed. The technique is a minimal invasive therapy, where a catheter is placed directly at the herniated disc or the scar tissue Methods Patient Selection This retrospective study of a case series of randomized patients was conducted in the Department of Neurosurgery and Anaesthesiology, Wan-Fang Medical Center, Taipei Medical University, Taipei, 10

Treating Lumbar Discogenic Pain Using Epidural Neuroplasty Taiwan. A total of patients 26 patients with a history of chronic low back pain and sciatica were assigned to the group underwent epidural neuroplasty between June and August 2007. The inclusion criteria were leg and back pain with MRI evidence of contained disc protrusion with a disk height 50%, after failed conservative therapy for 9 weeks. The exclusion criteria were disc height <50%, complete annular disruption revealed by discography, more than 2 symptomatic levels, history of open disk surgery at suspected levels and moderate to severe spinal stenosis. Provocative discography was then conducted on all subjects following International Association for the Study of Pain and International Spinal Injection Society guidelines. A concordant pain response accompanying the demonstration of contained disc by performing the dsicography, with a painless response at an adjacent spinal level, became the foundation for inclusion in the study. Patients' medical charts were reviewed, and pertinent data such as age, gender, history of drug and alcohol abuse, location of pain, levels of performed procedure, duration of the inserted via the sacral hiatus on the side opposite the suspected pathology after local anesthetic infiltration of the skin on the top of the gluteal fold. With confirmation of the correct placement of the needle in the epidural space, we injected 10 ml of iohexol (Omnipaque 240TM) after negative aspiration and visualized spread of the contrast medium (epidurogram). If a filling defect corresponding to the area of pain was present, we threaded a Racz catheter towards the filling defect Fig.(1). Confirmation of ventral placement of the catheter was done with the help of a lateral fluoroscopic view. After correct placement, 10 to 50 ml of preservative-free normal saline was injected into the filling defect to open up the adhered epidural space. Injection of an additional 2 to 3 ml of iohexol to visualize opening of the scarred area and to assure the spread of the injectate was within the epidural space. Both the needle and catheter were removed after injection of 4 ml of 40 mg/ml methylpredinisolone. Fig. 1. Anteroposterior view of correct placement of the catheter with confirmation by dye spread. Note that a filling defect was observed between L4/5 disc space. procedure, pre-and post-procedural visual analog scale (VAS) pain scores, Oswestry Disability Index(ODI), and medication intake were carefully evaluated. All patients were treated on an inpatient basis in the operating room of the surgery center. Percutaneous disc decompression using neuroplasty was performed under monitored anesthesia care in the usual sterile fashion. Under fluoroscopic, a caudal approach was selected to perform the epidural neuroplasty. The patient was still placed in the prone position with sterile drapes in position. A 15- or 16-gauge RKTM epidural needle was 11

Li Wei, Kung-Shing Lee, Man-Kit Siu, etal Outcome Measures Patients were evaluated by an independent evaluator Preoperatively and at 3, 6, and 12 months post-operatively. Data collected included VAS pain scores, pain medication intake, and Oswestry Disability Index including changes in performance levels of activities of daily living. At each evaluation, patients were asked to quantify their overall pain using a VAS pain score ranging from 0 to 10. Good reason for use of the VAS includes ease of use, previous validation and widespread use for measuring sensitivity to treatment effects, and its allowance for quantifiable statistical evaluations of significance. Functional status The Oswestry Disability Index is the most commonly used and recommended outcome measure tools used for assessing the disabling effects of lumbar spinal disorders. Analgesic intake Patients were also surveyed in regard to their use of analgesics. For the purposes of this study, analgesic use was considered to be reduced if a patient reported complete termination of analgesics intake or a daily reduction of 50% or more. Statistical Analyses Outcome measure data at baseline was compared longitudinally to evaluations taken at 3, 6, and 12 months post-treatment. Wilcoxon matched-pairs signedranks test was used for VAS pain score analysis. Furthermore, Fisher's exact test and the Wilcoxon ranks sum test were used to identify factors that were significantly associated with changes in other variables. All statistical tests were two-sided, and P values < 0.05 were considered to be statistically significant. Results Patient Demographics and Baseline Data. Analysis of outcomes of percutaneous disc decompression utilizing epidural neuroplasty was performed on 28 patients. Twelve men and sixteen women (45 25 years of age) were included in the group with epidural neuroplasty treatment. All patients gave written consent, and the study fulfilled the criteria of the ethics committee of Wan fang Hospital. Axial back pain was reported by six (21.42%) of the patients, while twenty-two (78.57%) reported back and leg pain. Most patients (78.57%) had pain for over 12- months duration. Mean procedure duration was 15 minutes for the epidural neuroplasty treatment. Post-Surgical Outcomes: There were no complications related to the procedures. All patients were successfully treated without any significant complications during the procedure. Hospital stays ranged from 2 to 4 days, with an average of 2.14 days. Twenty-eight patients had one disc treated; a total of 28 procedures were performed. The mean follow-up period was 12 1.6 months. Two candidates were lost to 1 year follow-up due to inadvertent disectomies. Mean VAS was reduced from a pre-procedure score of 7.58 to a post-procedure score of 2.71 at 3 months, 3.71 at 6 months and 4.00 at 12 months in the epidural neuroplasty group. Fig.(2). Overall patient satisfaction was 57.1 % (16 in 28 patients) at 3 months, 57.1 % at 6 months, and 57.7 % (15 in 26 patients) at the latest 12

Treating Lumbar Discogenic Pain Using Epidural Neuroplasty follow-up. Two patients were lost to 1 year follow-up Fig. 2. Mean pain VAS scores post-procedure over one year due to inadvertent surgeries. Twelve months of followup showed that 7 patients were completely satisfied with the treatment (mean score 0-2) and had complete resolution of symptoms, 8 patients obtained a good result (mean score 3-4), 5 patients received little benefit (mean score 5-7), and in 3 patients results were completely unsatisfactory (mean score 8-9). Pain Reduction VAS pain scores significantly decreased(vas reduction more then 4 in scale) for 85.3%, 80.2%, and 70.3 % of patients at 3, 6, and 12 months, respectively with a mean decrease of 4.0 (P < 0.0001), 3.71 (P < Table 1. Change in post-treatment VAS pain scores over one year. Follow Up 3 months 6 months 12 months 0.0001), and 2.71 (P < 0.0001) noted, respectively (Table 1). Mean Median Range -4-3 (-8.0, 0) -3.71-3 (-8.0, 0) -2.71-2 (-8.0, 0) ODI had decreased in treated patients with Signed-ranks test P valuei < 0.0001 < 0.0001 < 0.0001 combination procedures from a pre-procedure score of 21.5 8.1to a post-procedure score of 18.3 7.2 at 3 Discussion months, 22.6 8.6 at six months and 22.8 8.4at 12 months. Analgesic consumption was stopped or reduced in 20 patients at 3 months. The percentage of patients reporting a reduction in analgesics intake was 80 % at 3 months (P <0.0001), 77.3% at 6 months (P <0.0001), and 70.5% at 12 months (P <0.0001). Failure of Treatment and Complications We did not find any significant factors related to failure of treatment. However, in our study, there were no intra-operative or post-operative complications associated with epidural nucleoplasty. This retrospective study of caudal neuroplasty demonstrated a statistically significant improvement in VAS pain scores and functional status and a reduction in medication intake in a group of patients with radicular or axial low back pain who had failed conservative treatment. Chemical irritation is an important factor in the origin of back pain with or without radiculopathy. The nucleus pulposus has been identified as a source of chemicals which, when leaked into the spinal canal via a rent in the annulus fibrosus, produce irritation (12). Nerve roots that compressed by disc material often show the signs of inflammation. Substances that might leak from the disc and produce inflammation of nerve roots or meninges include lactic acid, glycoprotein, 13

Li Wei, Kung-Shing Lee, Man-Kit Siu, etal cytokines, and histamine. Inflammatory chemicals from the response to a damaged disc may activate or injure the dorsal root ganglion. Obviously, chemically induced irritation can occur in the absence of compression by the disc. Outside the disk, the anterior and posterior longitudinal ligaments, which may be stretched by herniation or chemically irritated by the release of inflammatory chemicals from within the disk, are also richly innervated, providing another potential source of pain (10). Our goal of treating discogenic low back pain and leg pain is primarily based on the mechanisms underlying postulated disc remodeling treatment, which results in reduction in levels of inflammatory mediators released into the epidural space and release of trapped nerve root by epidural neuroplasty. Although other studies have also shown an overall reduction in pain scores following percutaneous epidural adhesion releasing neuroplasty, these studies have only shown a general decline in pain relief over time. Interestingly, pain scores and medication use continued to increase and functional status continued to decline in our patients over the 12-month follow-up period compared to other previous investigations. Nevertheless, fifteen patients still showed either excellent or good result 12 months after the procedure. Pre-procedural discography provided substantial importance for assurance that no extravasations of contrast material were present and concordant level of disc to the origin of discogenic pain was the target before proceeding with the intervention thus allowing the result of the treatment to be optimum. While we believe the risk to be small, it should be taken under advisement while evaluating patient eligibility. We recommend applying this minimally invasive technique only in those patients with small (<6 mm) contained disc herniations, with a reduced disc height less than 50% and with annular integrity. However, to our best knowledge, there are no data from a randomized clinical study investigating whether this therapy is superior to treatment with physiotherapy. Our study has several limitations. The retrospective nature of this study is a disadvantage.the sample size is small and results may not be applicable to all patient populations. Despite these inherent weaknesses, the study does help to provide a preliminary outline for the planning of future prospective, randomized, controlled studies combining nucleoplasty with other minimally invasive interventional techniques. Conclusion The findings of this retrospective study suggest that epidural neuroplasty can be a safe and effective procedure for patients with radicular and axial low back pain secondary to contained herniated discs. Prospective, randomized, controlled studies are needed to further evaluate the long-term efficacy of percutaneous disc decompression and resolution of discogenic pain using epidural neuroplasty. References 1. Kuslich SD, Ulstrom CL, Michael CJ. The tissue origin of low back pain and sciatica: A report of pain response to tissue stimulation during operation on the lumbar spine using local anesthesia. Orthop Clin North Am 1991; 22:181-187. 2. Bogduk N, McGuirk B (eds). Causes and sources of 14

Treating Lumbar Discogenic Pain Using Epidural Neuroplasty chronic low back pain. In Medical Management of Acute and Chronic Low Back pain. An Evidence- Based Approach: Pain Research and Clinical Management, Vol. 13, Elsevier Science BV, Amsterdam, 2002, pp 115-126. 3. Bogduk N. Low back pain. In Clinical Anatomy of the Lumbar Spine and Sacrum,Churchill Livingstone, New York, 1997, pp 187-214. 4. Pang WW, Mok MS, Lin ML, Chang DP, Hwang MH. Application of spinal pain mapping in the diagnosis of low back pain-analysis of 104 cases. Acta Anaesthesiol Sin 1998; 36:71-74. 5. Manchikanti L, Singh V, Pampati V, Damron K, Barnhill R, Beyer C, Cash K. Evaluation of the relative contributions of various structures in chronic low back pain. Pain Physician 2001; 4:308-316. 6. Mixter WJ, Barr JS. Rupture of the intervertebral disc with involvement of the spinal canal. N Eng J Med 1934; 211:210-215. 7. Benzon HT.Epidural steroid injections for low back pain and lumbosacral radiculopathy. Pain. 1986 Mar;24(3):277-95. 8. Mixter WJ, Ayers JB. Herniation or rupture of the intervertebral disc into the spinal canal. N Engl J Med 1935; 213:385-395. 9. Crock HV. Isolated lumbar disc resorption as a cause of nerve root canal stenosis. Clin Orthop 1976; 10.Cautico W, Parker JC, Pappert E et al. An anatomical and clinical investigation of spinal meningeal nerves. Acta Neurochir (Wien) 1988; 90:139-143. 11.Racz GB, Noe C, Heavner JE. Selective spinal injections for lower back pain. Current Review of Pain 1999; 3:333-341. 12.Kuslich SD, Ulstrom CL, Michael CJ. The tissue origin of low back pain and sciatica. Orthopaedic Clin NA 1991; 22:181-187. 13. Stolker RJ, Vervest ACM, Groen GJ. The management of chronic spinal pain by blockades: A review. Pain 1994; 58:1-20. 14.Veihelmann A, Devens C, Trouillier H, Birkenmaier C, Gerdesmeyer L, Refior HJ. Epidural neuroplasty versus physiotherapy to relieve pain in patients with sciatica: a prospective randomized blinded clinical trial. J Orthop Sci. 2006 Jul;11(4):365-9. 15.Manchikanti L, Pampati V, Fellows B, Rivera J, Beyer CD, Damron KS.Role of one day epidural adhesiolysis in management of chronic low back pain: a randomized clinical trial. Pain Physician. 2001 Apr;4(2):153-66. 16.Heavner JE, Racz GB, Raj P.Percutaneous epidural neuroplasty: prospective evaluation of 0.9% NaCl versus 10% NaCl with or without hyaluronidase. Reg Anesth Pain Med. 1999 May-Jun;24(3):202-7.TABLES 115:109-115. 15

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