Early Failures of Percutaneous Epidural Neuroplasty Requiring Decompressive Lumbar Surgery - Clinical Research

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1 Original Article J. of Advanced Spine Surgery Volume 5, Number 2, pp 42~49 Journal of Advanced Spine Surgery JASS Early Failures of Percutaneous Epidural Neuroplasty Requiring Decompressive Lumbar Surgery - Clinical Research Seok Han, M.D., Doo Soo Kim,M.D., Seong Hoon Oh, M.D.,Ph.D., Tae-yeon Kim, M.D., Il-tae Jang, M.D.,Ph.D Spine Center, Nanoori Incheon Hospital, Incheon, Korea Purpose: The purpose of this study was to determine the early failure rate of percutaneous epidural neuroplasty (PEN) that led to subsequent decompressive lumbar surgery. We also assessed the limits of spinal pain management by using the current PEN technique. Materials and Methods: We classified 1763 cases according to their diagnoses and radiological findings. Patients who underwent subsequent open surgery when PEN failed to improve or aggravated their symptoms were included. Results: All 37 patients underwent open decompressive surgery within 3 months after PEN. There were 18 in the intracanalicular focal herniation category, 11 in intracanalicular broad based herniation category, and 8 in foraminal category; the early failure rates were 1.7%, 1.9%, and 5.6%, respectively. There was no significant statistical difference between the intracanalicular categories with regard to failure rate, but the foraminal category had a higher rate of failure than that of intracanalicular categories (p<0.05). Moreover, there were 11 cases in intracanalicular categories that experienced deterioration or new symptoms due to posterior longitudinal ligament rupture or fragment migration. Among these, there were 9 cases (82%) with preexisting intracanalicular migrating fragments. Conclusion: PEN with targeted drug delivery may be an effective treatment for low back pain and/or radiculopathy. However, its early failure rate is at least 2.1%, and the presence of intracanalicular migrating fragments or symptomatic foraminal lesions are predictors of poor outcome. Patients must be carefully selected on the basis of thorough radiologic reviews to improve the rate of satisfactory PEN outcomes. Keywords: Neuroplasty, Interventional failure, Lumbar surgery, Foraminal lesion, Migrating fragment INTRODUCTION Percutaneous epidural neuroplasty (PEN), lysis of epidural adhesion, is an interventional technique that was first described by Racz and Holubec 1) in The goal of this procedure is to eliminate barriers in the epidural space in order to facilitate the delivery of pain relieving drugs to target sites. 2) The technique requires the introduction of a navigable catheter into the epidural space. 3) Although it was first developed using a percutaneous approach via the sacral hiatus to treat chronic low back pain and/or lumbosacral radiculopathy, it is now also performed using transforaminal and interlaminar approaches. A recent systematic review detailed the evidence for the effectiveness for epidural adhesiolysis. 3-7) Like any invasive procedure, epidural adhesion lysis is associated with potential complications. 8) The most commonly reported are dural puncture, catheter shearing, and infection. 3,8-10) However, to our best knowledge, frag- Corresponding author: Seong Hoon Oh, M.D., Ph.D. Spine Center, Nanoori Incheon Hospital, Bupyeong-dong 124-5, Bupyeong-gu, Incheon, , Korea TEL: , FAX: torcula@naver.com 42 Copyright 2015 Korean Society for the Advancement of Spine Surgery

2 ment migration or rupture of the posterior longitudinal ligament, both of which require open decompressive surgery, have not been previously reported. Moreover, there is no existing systematic review of the failed PEN procedures. At our institution, there have been cases in which symptom worsening or lack of improvement following PEN necessitated subsequent open decompressive surgery. We examined these cases to determine the interventional failure rate and predictors of poor clinical results. Our results provide insight into the range of lumbosacral pathologies that can be effectively treated using current PEN techniques. MATERIALS AND METHODS Patient Population Patients with radiculopathies, post surgical epidural adhesions, lumbar disc diseases compressing nerve roots in the epidural space and spinal stenosis in low back were considered candidates for the PEN when other conservative management had been tried and found to be ineffective, and only after appropriate diagnostic evaluations were performed. 8,11,12) We retrospectively reviewed the outcomes of 1763 patients who received PEN in a single hospital between 2009 and 2011, and 37 cases that required subsequent decompressive surgery within 3 months after PEN were further evaluated. Waivers of informed consent and authorization were not obtained because this was a retrospective study that involved no direct patient contact. The inclusion criteria (failure of epidural intervention) was defined as follows: (1) lumbar disc herniation or stenosis that required subsequent open decompressive surgery due to lack of improvement or symptom worsening within 3 months after PEN; (2) confirmation of the aggravation of previous pathology by magnetic resonance (MR) images; and (3) no symptom-free interval between the epidural intervention and the subsequent surgery. The exclusion criteria were: (1) subsequent decompressive surgery > 3 months after PEN; (2) conservative management prior to percutaneous vertebroplasty. Patients clinical records and radiological examinations were reviewed. Descriptive statistics were used to analyze the variables, included chi-squared tests, analysis of variance (ANOVA), and Kruskal Wallis tests, as appropriate. Differences were considered significant if P-value was less than Clinical and Radiologic Classification The analysis was performed using pre- and post-operative MR and intra-operative C-arm images obtained during PEN. An analyst classified all cases, including the 37 open surgical cases, into 3 categories, intracanalicular focal disc herniation (A), intracanalicular broad based disc herniation (B), and foraminal lesions (C) according to the main radiological findings and medical records. Herniation was defined as a localized displacement of disc material beyond the limits of the intervertebral disc space. 13,14) The disc space was defined, craniad and caudad, by the vertebral body endplates and peripherally by the outer edges of the vertebral ring apophyses, exclusive of osteophytic formations. 13) The migrated disc was defined as a herniation, which was displaced away from the herniation site, either above the endplate of the upper body or below the endplate of the lower body. The hyperintense area on T2-weighted MR images of the disc was described as the high-intensity zone. (HIZ) 13) The category A in this study included patients with intracanalicular focal herniation, signifying localized displacement in the disc level axial plane < 25% of the disc circumference. 13) The category B included patients with intracanalicular broad-based herniation, with displacement between 25 and 50% of the disc circumference. 13) Patients in the category C had lesion in foraminal zone defined by the medial and lateral borders of the pedicles. 15) For patients with multi-segmental pathology or different pathologies at the same level, the primary category was determined either on the severity of lesion observed on imaging tests or patients clinical symptomatology. Interventional Epidural Technique All procedures were performed in the operating room under sterile conditions by utilizing fluoroscopic guidance. The procedure included appropriate preparation with intravenous access, antibiotic administration, and sedation with midazolam (1 to 2 mg); patients were sedated but conscious. Patients were placed prone on a horizontal operating table. Pillows were placed under the abdomen to facilitate sacral hiatus entry. After surgical field sterilization, the 43

3 sacral cornua were palpated and fluoroscopically confirmed. The cutaneous entry site was treated with 2% lidocaine before an 18-gauge Tuohy needle (RX-2 TM ; EPIMED, Johnstown, NY, USA) was introduced into the sacral hiatus. Needle position was confirmed under fluoroscopy in the lateral and anteroposterior views. After negative aspiration of blood and epidural fluid, we injected 10 ml water-soluble contrast medium (Iobrix 300; Taejoon Pharm, Seoul, Korea) to verify needle position in the caudal epidural space. A flexible Racz catheter was then passed through the needle and directed toward the target nerve roots under continuous fluoroscopy. After diffusion of the contrast medium into the epidural space, identification of the filling defects was carried out by examining contrast flow around the nerve root for category A (Fig. 1). The catheter positioning target sites were near the midline for the category B and below the pedicle for the category C. Next, 750 units hyaluronidase in 5 ml preservative-free normal saline were injected. Afterward, 5 ml 0.1% bupivacaine and 4 mg dexamethasone were injected through the Racz catheter in divided doses after negative aspiration. A second injection was administered 6 h after the first. The Racz catheter and epidural needle were then removed, and a sterile occlusive dressing was applied over the injection site. Patients were allowed to ambulate 2 h after the procedure and were discharged as soon as they Fig. 1. The epidural filling defect (arrow) and typical proximal position of Racz catheter for category A are illustrated. were able to walk independently (generally within 24 h after PEN). RESULTS From January 2009 to December 2011, 13 spinal clinicians at our institute employed PEN techniques to treat 2056 patients with spinal disorders diagnosed from X-rays and MR images. There were 1051 cases in category A, 570 cases in category B, and 142 cases in category C. The remaining 293 patients were cases of acute sprains, cervical lesions, acute vertebral compression fracture, or had insufficient or poor quality preinterventional radiologic evaluations that were not compatible with the study. The annual patient characteristics are listed in Table 1. Although there was significant difference in the proportion of each group at annual study, the early failure rates for the procedure were comparable for all 3 years. A total of 78 patients underwent subsequent open decompressive surgery at the index level, and of these, 37 cases satisfied the inclusion criteria and were included in the analysis. The remaining 41 patients experienced symptom improvement after the epidural intervention or underwent subsequent decompressive surgery after 3 months. The characteristics of included 37 patients are listed in Table 2. The overall interventional failure rate was 1.8% (37/2056), and the failure rate of cases in the 3 categories described above was 2.1% (37/1763). Open decompressive surgeries included 4 cases of posterior lumbar interbody fusion, 2 of anterior lumbar interbody fusion, 3 of transforaminal lumbar interbody fusion, 22 of lumbar laminectomy and discectomy, 4 of paraspinal decompression, and 2 of subarticular fenestration. Patients were affected at different spinal levels, including L3/4 (3), L4/5 (15), L5/S1 (12), and multilevel (7). The incidence of failure was significantly higher in the category C compared to category A or B (5.6%, P < 0.05). However, there was no significant difference in the rate of failure between the category A and B (1.7% and 1.9%, respectively). It is noteworthy that a total of 11 patients in the category A or B developed radiating leg symptoms because of newly developed rupture fragments (Fig. 2) or migration of preexisting fragments (Fig. 3), which were confirmed in followup MR images after PEN. The incidence of aggravation 44

4 A B A B Fig. 2. A 52-year-old female presented with back pain. Magnetic resonance image (A) shows L5/S1 disc space narrowing and degeneration with an upward-migrating fragment (arrow in A). She returned because of severe radiating pain in her left leg. Follow-up magnetic resonance image (B) reveals a developing transligamentous rupture fragment at L5/S1 (arrow in B). Fig. 3. A 39-year-old female presented with back pain. Magnetic resonance image (A) demonstrates a left paracentral downwardmigrating fragment at L5/S1 (arrow in A). She returned 1 week after percutaneous epidural neuroplasty because of severe radiating pain in her right leg. Magnetic resonance image (B) demonstrates right-side migration of the previously detected fragment (arrow in B). Table 1. Summary of annual patient ch aracteristics(n=1763) Years 1 (418) Years 2 (560) Years 3 (785) Total (1763) p-value Failure (%) 10 (2.4) 11 (2.0) 16 (2.0) 37 (2.1) NS Average age (yr) 44.7± ± ± ±13.7 NS* Male:Female 1:1.5 1:1.2 1:1.3 1:1.3 NS Period(%) Category A Category B Category C 250 (59.8) 123 (29.4) 45 (10.8) 286 (51.1) 246 (43.9) 28 (5.0) 515 (69.6) 201 (25.6) 69 (8.8) 1051 (59.6) 570 (32.3) 142 (8.1) <0.05 NS, not significant, *ANOVA Table 2. Characteristics summary of failed cases (n=37) Category A (18) Category B (11) Category C (8) Total (37) p-value Average age (yr) 40 ± ± ± ± 14.4 <0.05* Male:Female 1:0.8 1:4.5 1:1 16/37 NS Median time to op (days) NS Range (days) (2-90) (4-50) (3-90) Aggravation (%) 8 (0.7) 3 (0.5) 0 11 (0.6) NS NS: not significant, *: ANOVA, : Kruskal Wallis test. was 0.6% (11/1763) in all included procedures and 0.7% (11/1621) in category A or B. The common levels of transligamentous rupture were L4/5 and L5/S1, and the responsible levels were L3/4, L4/5, and L5/S1 in 1, 5, and 5 patients, respectively. In 9 patients (82%), the authors observed a preexisting intracanalicular migrating fragment, mostly tiny and subtle on preinterventional MR images. However, the HIZ on T2-weighted MR images was only demonstrated in 3 patients (27%) (Table 3). The incidence of rupture or fragment migration was significantly higher in patients with preexisting intracanalicular migrating fragments than those without (p<0.01). However, the presence of intracanalicular HIZ was not significantly associated with clinical or radiological deterioration (Table 4). Although there were preexisting migrating portions in preprocedure MR images, none of the 11 patients who showed deterioration after PEN had radiating leg pain or weakness prior to the intervention, and their intraoperative findings were not unusual. 45

5 Table 3. Summary of deteriorated patient characteristics Age/sex Category Duration to op.(days) Level/side Migrating fragment HIZ Rupture direction Case 1 26/M A 19 L4/5 Lt. + - down Case 2 37/M A 31 L5/S1 Lt. + + down Case 3 33/F A 10 L4/5 Rt. + + down Case 4 46/M A 19 L4/5 Lt. + - down Case 5 40/M A 54 L5/S1 Lt. + - down Case 6 52/F A 46 L5/S1 Lt. + - up Case 7 44/F A 7 L4/5 Lt. + - up Case 8 39/F A 12 L5/S1 Rt. + - down Case 9 61/F B 9 L5/S1 Rt. - - down Case 10 61/M B 28 L3/4 Lt. + + down Case 11 46/M B 14 L4/5 Rt. - - down Table 4. Comparison of aggravation incidence in cases with preexisting intracanalicular migrating fragments and HIZ (n = 1763) Migration fragment Yes (n = 164) No (n = 1599) HIZ Yes (n = 895) No (n = 868) NS, not significant. DISCUSSION Aggravation (%) 9 (5.5) 2 (0.1) 3 (0.3) 8 (0.9) P-value <0.01 Low back pain is a chronic painful condition that causes serious clinical, social, economic, and public health care problems. It is difficult to treat the patients with low back pain with/without radiculopathy, who generally experience chronic pain that is refractory to most treatment modalities, such as pharmacologic agents, physical therapy, and epidural steroid administrations. The PEN protocol described by Racz has become an increasingly common choice to manage chronic resistant spinal pain. 8,12,16) Epidural adhesiolysis improves the delivery of various medications to a lesionspecific site by placing the tip of a soft spring catheter or a fiberoptic endoscope within the scarred tissue and opens the perineural space. Then, steroids and other solutions can reach the damaged area and provide an anti-inflammatory NS effect and neural blockage. 3) Racz and other physicians have described their experience with epidural adhesion lysis. 8,11,17) Heavner et al. concluded that the patients who were treated with hypertonic saline and hyaluronidase for low back pain and radiculopathy obtained greater pain relief and were less likely to require other types of treatment in comparison to patients that only received isotonic or hypertonic saline. 4) Hypertonic saline is hyperosmolar and increases volume and pressure in loculated compartments by osmotically drawing fluid into the space, 2) and the rationale for hyaluronidase use is its purported ability to disrupt epidural adhesions. 18) Its primary action is depolymerizing hyaluronic acid and, to some extent, chondrotin-4 and chondrotin-6 sulfates. 18) Hyaluronidase disrupts the proteoglycan ground substance in epidural adhesions and increases the diffusion of administrated therapeutic agents. 18) The dura, which is composed of collagen, elastin and surface fibroblast, is preserved. 4,18) Manchikanti et al. also reported that nonendoscopic epidural administration of corticosteroids and hypertonic saline is a safe and cost-effective treatment for chronic intractable pain in postlaminectomy patients who do not respond to other treatment modalities. 19) There have been numerous studies regarding PEN effectiveness. 3-7) The majority met rigorous and methodological criteria and showed positive short-term improvement (within 3 months) in pain status and other parameters. 3) However, to our knowledge, the analysis of failed cases, especially 46

6 those who required open decompressive surgery following PEN, has not been previously reported. The overall failure rate of PEN was 2.1% in this study, and this result is a minimal numerical value considering patient dissatisfaction after PEN, follow-up loss during the study period, long-term results, and highly stringent failure criteria of this study (open decompressive surgery). Therefore, this is a conservative estimate. The reason for the higher failure rate in the category C in this study may be from the scanty volume of foraminal zone, resulting in reduced access for epidurally administered drugs and more technically demanding approaches to the exact lesion site, especially L5/S1 level. Therefore, symptomatic lumbar foraminal lesion could be a predictor of poor PEN outcome, and the significant difference in proportion of each group at annual study listed in Table 1 was not caused by a significant variable (category C). Although Gerdesmeyer and colleagues treated 25 patients with monosegmental lumbar radiculopathy using PEN and noted improvements in Oswestry scores and no worsening of symptoms, 20,21) we observed 11 cases of symptom worsening after PEN, and the major cause was the aggravation of preexisting intracanalicular migrating fragments. The high proportion of caudal lumbar segment involvement in this investigation suggested the possibility of mechanical injury by the flexible catheter during the procedure. Further, the posterior longitudinal ligament extends laterally at the disc level, but above and below the disc, there is an anterior epidural space between the thin lateral (peridural) membranes and the posterior aspect of the vertebral bodies where disc fragments are frequently entrapped. 13,22) Furthermore, by definition, the migrating fragments in the anterior epidural space have no annulus covering composed of type I collagen. Therefore, it is presumed that the disrupting effects in the ground substance of hyaluronidase affect the migration of preexisting fragments in the anterior epidural space. We have since skipped administering hyaluronidase for patients who have intracanalicular migrating fragments at L5/S1 and have not yet encountered cases that deteriorated after PEN Like all invasive treatment modalities, PEN is prone to various problems and complications due to the procedure itself; to the solutions used during the procedure; or patient physical, social, and psychological status. 8) In order to prevent complications and interventional failure, PEN must only be considered in patients who have undergone multidisciplinary evaluation and when other conservative managements have failed, 8) also only be performed by experienced physicians in well-equipped centers. CONSLUSION Despite the effectiveness of PEN with targeted drug delivery in patients with low back pain with or without radiculopathy, its short-term failure rate is at least 2.1%, and its aggravation rate for intracanalicular lesion is 0.7%. Symptomatic lumbar foraminal lesions or the presence of preexisting intracanalicular migrating fragments and are predictors of poor PEN outcomes. Our findings suggest careful case selection and thorough pre-procedure radiologic reviews to facilitate satisfactory PEN results. Future studies regarding long-term results and additional risk factors of ruptured lumbar disc after PEN are necessary and ongoing. REFERENCES 1. Racz GB, Holubec JT. Lysis of adhesions in the epidural space in Racz GB. (Techniques of Neurolysis. Boston, Kluwer: 57-72, 1989). 2. Ho KY, Manghnani P. Acute monoplegia after lysis of epidural adhesions: a case report. Pain Pract. 2008;8: Trescot AM, Chopra P, Abdi S, et al. Systematic review of effectiveness and complications of adhesiolysis in the management of chronic spinal pain: an update. Pain Physician. 2007;10: Heavner JE, G.B.Racz, Raj P. Percutaneous epidural neuroplasty: prospective evaluation of 0.9% NaCl versus 10% NaCl with or without hyaluronidase. Reg Anesth Pain Med. 1999;10: Manchikanti L, Pampati V, Fellows B, et al. Role of one day epidural adhesiolysis in management of chronic low back pain: A randomized clinical trial. Pain Physicain. 2001;4: Manchikanti L, Rivera J, Pampati V, et al. One day lum- 47

7 bar epidural adhesiolysis and hypertonic saline neurolysis in treatment of low back pain: A randomized double blind trial. Pain Physicain. 2004;7: Veihelmann A, Devens C, Trouiller H, et al. Epidural neuroplasty versus physiotheraphy to relieve pain in patients with sciatica: A prospective randomized blinded clinical trial. Orthop Science 2006;11: Talu GK, Erdine S. Complications of epidural neuroplasty: A prospective evaluation. Neuromodulation. 2003;6: Perkins WJ, Davis DH, Huntoon MA, et al. A retained Racz catheter fragment after epidural neurolysis: implications during magnetic resonance imaging. Anesth Analg. 2003;96: Wagner KJ, Sprenger T, Pecho C, et al. Risks and complications of epidural neurolysis - a review with case report. Anesthesiol Intensmed Noffallmed Schmerzther 2006;41: Manchikanti L, Bakhit CE. Percutaneous lysis of epidural adhesions. Pain Physician. 2000;3: Racz GB, GHeavner JE, Raj PP. Nonsurgical management of spinal radiculopathy by the use of lysis of adhesions (neuroplasty) in Gerald M. (Evaluation, Treatment of Chronic Pain. Baltimore, Williams and Wilkins: , 1994). 13. Fardon DF, Milette PC, Combined Task Forces of the North American Spine Society ASoSR, American Society of N. Nomenclature and classification of lumbar disc pathology. Recommendations of the Combined task Forces of the North American Spine Society, American Society of Spine Radiology, and American Society of Neuroradiology. Spine (Phila Pa 1976). 2001;26:E93- E Jeon E-H, Song J-H, Park H-K, et al. Interobserver and Intraobserver Variability in Interpretation of Lumbar Disc Abnormalities on Magnetic Resonance Images. J Korean Neurosug Soc. 2001; Wiltse LL, Berger PE, McCulloh JA. A system for reporting the size and locations of lesions of the spine. Spine (Phila Pa 1976). 1997;22: Racz GB, Heavner JE, Diede JH. Lysis of epidural adhesions utilizing the epidural approach in Winnie W. (Interventional Pain Management. Philadelphia, Saunders: , 1996). 17. Manchikanti L, Pakanati RR, Bakhit CE, Pampati V. Role of adhesiolysis and hypertonic saline neurolysis in management of low back pain: Evaluation of modification of the Racz Protocol. Pain Digest 1999;9: Yousef AA, AS EL-D, Al-Deeb AE. The role of adding hyaluronidase to fluoroscopically guided caudal steroid and hypertonic saline injection in patients with failed back surgery syndrome: a prospective, double-blinded, randomized study. Pain Pract. 2010;10: Manchikanti L, Pampati V, Bakhit CE, et al. Non-endoscopic and endoscopic adhesiolysis in post-lumbar laminectomy syndrome: a one-year outcome study and cost effectiveness analysis. Pain Physician. 1999;2: Gerdesmeyer L, Rechl H, Wagenpfeil S, et al. Minimally invasive percutaneous epidural neurolysis in chronic radiculopathy. A prospective controlled pilot study to prove effectiveness. Orthopade. 2003;32: Gerdesmeyer L, Lampe R, Veihelmann A, et al. Chronic radiculopathy. Use of minimally invasive percutaneous epidural neurolysis according to Racz. Schmerz. 2005;19: Milette PC. Classification, diagnostic imaging, and imaging characterization of a lumbar herniated disk. Radiol Clin North Am. 2000;38:

8 경피적신경성형술후요추감압술이조기에필요했던시술실패요인 한석, 김두수, 오성훈, 김태연, 장일태인천나누리병원척추센터 목적 : 경피적신경성형술후조기에요추감압술이필요했던시술실패에대한요인및경피적신경성형술의기술적한계에대해분석하였다. 방법 : 경피적신경성형술후호전이없거나악화되어감압술을시행한환자군을포함한시술환자총 1763명을진단과영상소견에따라분류했다. 결과 : 경피적신경성형술후 3개월내에수술한경우는 37례였다. 이중 18명은신경관내국소적으로돌출된추간판탈출군으로부류되었고, 11명은신경관내넓게돌출된추간판탈출군이었으며, 8명은척추간신경공내추간판탈출군이었다. 시술후조기감압술은각각 1.7%, 1.9%, 5.6% 에서시행되었으며, 척추간신경공내탈출군에서신경관내탈출군보다수술률이높았다 (P < 0.05). 11 명의신경관내파열군환자에서는후종인대의파열이나추간판전위로인한기존증상의악화나추가증상발생이나타났으며, 이중 9명 (82%) 에서는시술전부터존재하던신경관내전위된추간판조각이존재했던환자였다. 결론 : 경피적신경성형술은요통과방사통에효과적인치료법이나시술후실패율은최소 2.1% 이었고, 신경관내전위된추간판조각의존재나증상과동반된척추간신경공내병변이나쁜예후예측인자였다. 영상학적소견에따라시술대상환자를신중히선택하여야보다좋은결과를얻을수있었다. 색인단어 : 신경성형술, 중재적시술실패, 요추수술, 척추간신경공내병변, 전위된조각 49