An analysis of reasons for failed back surgery syndrome and partial results after different types of surgical lumbar nerve root decompression.

BACKGROUND: Despite the evident progress in treating vertebral column degenerative diseases, the rate of a so-called "failed back surgery syndrome" associated with pain and disability remains relatively high. However, this term has an imprecise definition and includes several different morbid conditions following spinal surgery, not all of which directly illustrate the efficacy of the applied technology; furthermore, some of them could even be irrelevant. OBJECTIVE: To evaluate and systematize the reasons for persistent pain syndromes following surgical nerve root decompression. STUDY DESIGN: Prospective, nonrandomized, cohort study of 138 consecutive patients with radicular pain syndromes, associated with nerve root compression caused by lumbar disc herniation, and resistant to conservative therapy for at least one month. The minimal period of follow-up was 18 months. SETTING: Hospital outpatient department, Russian Federation METHODS: Pre-operatively, patients were examined clinically, applying the visual analog scale (VAS), Oswestry Disability Index (ODI), magnetic resonance imaging (MRI), discography and computed tomography (CT). According to the disc herniation morphology and applied type of surgery, all participants were divided into the following groups: for those with disc extrusion or sequester, microdiscectomy was applied (n = 65); for those with disc protrusion, nucleoplasty was applied (n = 46); for those with disc extrusion, nucleoplasty was applied (n = 27). After surgery, participants were examined clinically and the VAS and ODI were applied. All those with permanent or temporary pain syndromes were examined applying MRI imaging, functional roentgenograms, and, to validate the cause of pain syndromes, different types of blocks were applied (facet joint blocks, paravertebral muscular blocks, transforaminal and caudal epidural blocks). RESULTS: Group 1 showed a considerable rate of pain syndromes related to tissue damage during the intervention; the rates of radicular pain caused by epidural scar and myofascial pain were 12.3% and 26.1% respectively. Facet joint pain was found in 23.1% of the cases. Group 2 showed a significant rate of facet joint pain (16.9%) despite the minimally invasive intervention. The specificity of Group 3 was the very high rate of unresolved or recurred nerve root compression (63.0%); in other words, in the majority of cases, the aim of the intervention was not achieved. The results of the applied intervention were considered clinically significant if 50% pain relief on the VAS and a 40% decrease in the ODI were achieved. LIMITATIONS: This study is limited because of the loss of participants to follow-up and because it is nonrandomized; also it could be criticized because the dynamics of numeric scores were not provided. CONCLUSION: The results of our study show that an analysis of the reasons for failures and partial effects of applied interventions for nerve root decompression may help to understand better the efficacy of the interventions and could be helpful in improving surgical strategies, otherwise the validity of the conclusion could be limited because not all sources of residual pain illustrate the applied technology efficacy. In the majority of cases, the cause of the residual or recurrent pain can be identified, and this may open new possibilities to improve the condition of patients presenting with failed back surgery syndrome.

Differential treatment of nerve root compression pain caused by lumbar disc herniation applying nucleoplasty.

BACKGROUND: Nucleoplasty is a minimally invasive intervention use to perform disc decompression in cases of nerve root compression caused by disc herniation. It is important to find rational guidelines for choosing between nucleoplasty and microsurgery. OBJECTIVE: To analyze factors that may impact the results of nucleoplasty, and to validate the rational guidelines between minimally invasive treatment and open surgery. STUDY DESIGN: Prospective, non-randomized, cohort study with a minimal follow-up period of 18 months. METHODS: Patients were given a neurological examination, visual analogue scale and Oswestry disability questionnaire, obligatory MRI, optional RCT, and discography, only before nucleoplasty. Patients have been divided into the following groups: Group 1 - patients with a disc protrusion treated with nucleoplasty (n = 46), which has been divided into Subgroup 1A, those with a disc protrusion size ≤ 5 mm (n = 24), and Subgroup 1B, those with a disc protrusion size 6 - 9 mm (n = 22); Group 2 - patients with a disc extrusion treated with nucleoplasty (n = 27); Group 3 - patients with a disc extrusion or sequester treated with microdiscectomy (n = 65). OUTCOME MEASURES: Clinically significant outcomes were a 50% relief of pain intensity and a 40% decrease of Oswestry Disability Index (ODI). RESULTS: A decrease of pain intensity and disability was found in all groups of patients, P < 0.0001; SP (statistical power) = 99 - 100%. Subgroups 1A and 1B showed no clinically significant differences in outcome, P = 0.99; SP = 5.3. Clinically significant results: Group 1 - 78%; 95% CI (confidence interval) [66; 90%], Group 2 - 44%; 95% CI [25; 65%], Group 3 - 93%; 95% CI [85; 98%]. Total annulus disruption increases the rate of unsatisfactory results of nucleoplasty, OR (odds ratio) = 4.5; 95% CI [1.57; 12.87] (logistic regression model, P = 0.0034). Nucleoplasty performed in cases of uncontained disc herniation (disc extrusion) have a significantly higher rate of unsatisfactory results versus microdiscectomy, OR = 19.06; 95% CI [2.29; 68.73] (logistic regression model, P < 0.0001). LIMITATIONS: This study was limited by the small number of patients in each group. CONCLUSION: The size of the disc protrusion does not significantly affect the outcome of nucleoplasty. The rational guideline for choosing between the 2 types of surgery is the integrity of the annulus.