Anterolateral versus posterior minimally invasive lumbar interbody fusion surgery for spondylolisthesis: comparison of outcomes from a global, multicenter study at 12-months follow-up.

BACKGROUND CONTEXT: Several minimally invasive lumbar interbody fusion techniques may be used as a treatment for spondylolisthesis to alleviate back and leg pain, improve function and provide stability to the spine. Surgeons may choose an anterolateral or posterior approach for the surgery however, there remains a lack of real-world evidence from comparative, prospective studies on effectiveness and safety with relatively large, geographically diverse samples and involving multiple surgical approaches. PURPOSE: To test the hypothesis that anterolateral and posterior minimally invasive approaches are equally effective in treating patients with spondylolisthesis affecting one or two segments at 3-months follow-up and to report and compare patient reported outcomes and safety profiles between patients at 12-months post-surgery. DESIGN: Prospective, multicenter, international, observational cohort study. PATIENT SAMPLE: Patients with degenerative or isthmic spondylolisthesis who underwent 1- or 2-level minimally invasive lumbar interbody fusion. OUTCOME MEASURES: Patient reported outcomes assessing disability (ODI), back pain (VAS), leg pain (VAS) and quality of life (EuroQol 5D-3L) at 4-weeks, 3-months and 12-months follow-up; adverse events up to 12-months; and fusion status at 12-months post-surgery using X-ray and/or CT-scan. The primary study outcome is improvement in ODI score at 3-months. METHODS: Eligible patients from 26 sites across Europe, Latin America and Asia were consecutively enrolled. Surgeons with experience in minimally invasive lumbar interbody fusion procedures used, according to clinical judgement, either an anterolateral (ie, ALIF, DLIF, OLIF) or posterior (MIDLF, PLIF, TLIF) approach. Mean improvement in disability (ODI) was compared between groups using ANCOVA with baseline ODI score used as a covariate. Paired t-tests were used to examine change from baseline in PRO for both surgical approaches at each timepoint after surgery. A secondary ANCOVA using a propensity score as a covariate was used to test the robustness of conclusions drawn from the between group comparison. RESULTS: Participants receiving an anterolateral approach (n=114) compared to those receiving a posterior approach (n=112) were younger (56.9 vs 62.0 years, p <.001), more likely to be employed (49.1% vs 25.0%, p<.001), have isthmic spondylolisthesis (38.6% vs 16.1%, p<.001) and less likely to only have central or lateral recess stenosis (44.9% vs 68.4%, p=.004). There were no statistically significant differences between the groups for gender, BMI, tobacco use, duration of conservative care, grade of spondylolisthesis, or the presence of stenosis. At 3-months follow-up there was no difference in the amount of improvement in ODI between the anterolateral and posterior groups (23.2 ± 21.3 vs 25.8 ± 19.5, p=.521). There were no clinically meaningful differences between the groups on mean improvement for back- and leg-pain, disability, or quality of life until the 12-months follow-up. Fusion rates of those assessed (n=158; 70% of the sample), were equivalent between groups (anterolateral, 72/88 [81.8%] fused vs posterior, 61/70 [87.1%] fused; p=.390). CONCLUSIONS: Patients with degenerative lumbar disease and spondylolisthesis who underwent minimally invasive lumbar interbody fusion presented statistically significant and clinically meaningful improvements from baseline up to 12-months follow-up. There were no clinically relevant differences between patients operated on using an anterolateral or posterior approach.

Circumferential Fusion Employing Transforaminal vs. Direct Lateral Lumbar Interbody Fusion-A Potential Impact on Implants Stability.

Background: Different fusion techniques were introduced in clinical practice in patients with lumbar degenerative disc disease, however, no evidence has been provided on the advantages of one technique over another. The Objective of This Study: Is to assess the potential impact of circumferential fusion employing transforaminal lumbar interbody fusion (TLIF) vs. direct lateral interbody fusion (DLIF) on pedicle screw stability. Materials and Methods: This is a single-center prospective evaluation of consecutive 138 patients with degenerative instability of lumbar spinal segments. Either conventional transforaminal lumbar interbody fusion (TLIF) with posterior fusion or direct lateral interbody fusion (DLIF) using cages of standard dimensions, were applied. The conventional open technique was used to supplement TLIF with pedicle screws while percutaneous screw placement was used in patients treated with DLIF. The duration of the follow-up accounted for 24 months. Signs of pedicle screws loosening (PSL) and bone union after fusion were assessed by the results of CT imaging. Fisher's exact test was used to assess the differences in the rate of CT loosening and revision surgery because of implant instability. Logistic regression was used to assess the association between potential factors and complication rate. Results: The rate of PSL detected by CT and relevant revision surgery in groups treated with TLIF and DLIF accounted for 25 (32.9%) vs. 2 (3.2%), respectively, for the former and 9 (12.0%) vs. 0 (0%) for the latter (p < 0.0001 and p = 0.0043) respectively. According to the results of logistic regression, a decrease in radiodensity values and a greater number of levels fused were associated with a rise in PSL rate. DLIF application in patients with radiodensity below 140 HU was associated with a considerable decrease in complication rate. Unipolar or bipolar pseudoarthrosis in patients operated on with TLIF was associated with a rise in PSL rate while patients treated with DLIF tolerate delayed interbody fusion formation. In patients treated with TLIF supplementary total or partial posterior fusion resulted in a decline in PSL rate. Conclusion: Even though the supplementary posterior fusion may considerably reduce the rate of PSL in patients treated with TLIF, the application of DLIF provide greater stability resulting in a substantial decline in PSL rate and relevant revision surgery.

Case Report: Simultaneous Resection of Bone Tumor and CAD/CAM Titanium Cranioplasty in Fronto-Orbital Region.

Background: Simultaneous resection of bone tumors in the fronto-naso-orbital region is a great challenge due to the need for adequate reconstruction of the facial skeleton. Pre-operative virtual planning of resection margins and the simultaneous fabrication of the cranioplasty using computer-aided design/computer-aided manufacturing (CAD/CAM) technology could allow combining the tumor resection and cosmetic restoration steps into a single procedure. Methods: We present five consecutive cases of patients with bone tumors of the fronto-naso-orbital region. The indications for surgery included: (1) the presence of a major cosmetic defect; (2) progressive tumor growth. The histological examination revealed vascular malformation, hemangioma, and fibrous dysplasia in two cases. Tumor resection was performed with the help of a drilling template in form of a tumor. The computer-designed cranioplasty formed based on the non-involved side of the skull of the patient was manufactured. In one patient, the reconstruction was performed using two separate implants. Results: The position of the implant fits in with pre-operative planning in two cases; in those cases, the additional trimming of the implant or bone defect was required. Good cosmetic outcomes were noted in all patients, and no complications occurred. No repeat surgery was necessary. The template has proved to have high application potential. Conclusion: Simultaneous resection and CAD/CAM cranioplasty in the case of bone tumors in the fronto-orbital region is a promising technique with the aim of minimizing operation time and achieving a good esthetic outcome.

Potential contribution of pedicle screw design to loosening rate in patients with degenerative diseases of the lumbar spine: An observational study.

BACKGROUND: The majority of published data report the results of biomechanical tests of various design pedicle screw performance. The clinical relevance and relative contribution of screw design to instrumentation stability have been insufficiently studied. AIM: To estimate the contribution of screw design to rate of pedicle screw loosening in patients with degenerative diseases of the lumbar spine. METHODS: This study is a prospective evaluation of 175 patients with degenerative diseases and instability of the lumbar spine segments. Participants underwent spinal instrumentation employing pedicle screws with posterior only or transforaminal interbody fusion. Follow-up was for 18 mo. Patients with signs of pedicle screw loosening on computed tomography were registered; logistic regression analysis was used to identify the factors that influenced the rate of loosening. RESULTS: Parameters included in the analysis were screw geometry, type of thread, external and internal screw diameter and helical pitch, bone density in Hounsfield units, number of levels fused, instrumentation without anterior support, laminectomy, and unilateral and bilateral total facet joint resection. The rate of screw loosening decreased with the increment in outer diameter, decrease in core diameter and helical pitch. The rate of screw loosening correlated positively with the number of fused levels and decreasing bone density. Bilateral facet joint removal significantly favored pedicle screw loosening. The influence of other factors was insignificant. CONCLUSION: Screw parameters had a significant impact on the loosening rate along with bone quality characteristics, the number of levels fused and the extensiveness of decompression. The significance of the influence of screw parameters was comparable to those of patient- and surgery-related factors. Pedicle screw loosening was influenced by helical pitch, inner and outer diameter, but screw geometry and thread type were insignificant factors.

Porous Polymer Scaffolds based on Cross-Linked Poly-EGDMA and PLA: Manufacture, Antibiotics Encapsulation, and In Vitro Study.

Porous polymer materials derived from poly(ethylene glycol dimethacrylate) (poly-EGDMA) and antibiotic containing polylactide (PLA) are obtained for the first time. Porous poly-EGDMA monoliths with a system of open interconnected pores are synthesized by a visible light-induced radical polymerization of EGDMA in the presence of 70 wt% of porogenic agent, e.g., 1-butanol, 1-hexanol, 1-octanol, or cyclohexanol. The porosity of the obtained polymers is 75-78%. A modal pore size depends on the nature of the porogen and varies from 0.5 µm (cyclohexanol) to 12 µm (1-butanol). The polymer matrix made with 1-butanol features the presence of pores ranging from 1 to 100 µm. The pore surface of poly-EGDMA matrices is inlayered with poly-D,L-lactide (Mn  23 × 103  Da, PDI 1.31). The PLA-modified poly-EGDMA retains a porous structure that is similar to the initial poly-EGDMA but with improved strength characteristics. The presence of antibiotic containing PLA ensures a high and continuous antibacterial activity of the hybrid polymeric material for 7 days. The nontoxicity of all the porous matrices studied makes them promising for clinical tests as osteoplastic materials.

Early Management of Cervical Spine Trauma: WFNS Spine Committee Recommendations.

Epidemiology, prevention, early management of cervical spine trauma and it's reduction are the objectives of this review paper. A PubMed and MEDLINE search between 2009 and 2019 were conducted using keywords. Case reports, experimental studies, papers other than English language and and unrelated studies were excluded. Up-to-date information on epidemiology of spine trauma, prevention, early emergency management, transportation, and closed reduction were reviewed and statements were produced to reach a consensus in 2 separate consensus meeting of World Federation of Neurosurgical Societies (WFNS) Spine Committee. The statements were voted and reached a positive or negative consensus using Delphi method. Global incidence of traumatic spinal injury is higher in low- and middle-income countries. The most frequent reasons are road traffic accidents and falls. The incidence from low falls in the elderly are increasing in high-income countries due to ageing populations. Prevention needs legislative, engineering, educational, and social efforts that need common efforts of all society. Emergency care of the trauma patient, transportation, and in-hospital acute management should be planned by implementing detailed protocols to prevent further damage to the spinal cord. This review summarizes the WFNS Spine Committee recommendations on epidemiology, prevention, and early management of cervical spine injuries.

Relationship among anesthesia technique, surgical stress, and cognitive dysfunction following spinal surgery: a randomized trial.

OBJECTIVE: Surgical trauma is known to result in systemic inflammatory changes that can lead to postoperative cognitive dysfunction. In the present study, the authors compared the effects of an epidural anesthesia protocol to those of traditional anesthesia with regard to postoperative inflammatory changes, cellular immunity, and cognitive dysfunction. METHODS: Forty-eight patients, ages 45-60 years, underwent multilevel thoracolumbar decompression and fusion and were randomly assigned to one of two groups: group 1 (27 patients) had combined epidural and general anesthesia, followed by epidural analgesia for 48 hours after surgery, and group 2 (21 patients) had general anesthesia, followed by traditional opioid pain management after surgery. At multiple time points, data on pain control, cognitive function, cellular immunity, and inflammatory markers were collected. RESULTS: Group 1 patients demonstrated lower pain levels, less systemic inflammation, less cellular immune dysfunction, and less postoperative cognitive dysfunction than group 2 patients. CONCLUSIONS: The use of combined epidural and general anesthesia followed by postoperative epidural analgesia during the first 48 hours after multilevel thoracolumbar decompression and fusion surgery had a significant positive effect on pain management, cellular immune function, systemic inflammation, and postoperative cognitive function.Clinical trial registration no.: 115080510080 (http://rosrid.ru).

Pedicle Screws Loosening in Patients With Degenerative Diseases of the Lumbar Spine: Potential Risk Factors and Relative Contribution.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine risk factors that may affect the rate of pedicle screws loosening in patients with degenerative diseases of the lumbar spine. METHODS: A total of 250 patients with a low-grade spondylolisthesis and lumbar instability associated with degenerative diseases were enrolled. Preoperatively patients underwent computed tomography (CT) and cancellous bone radiodensity of a vertebral body was measured in Hounsfield units (HU). Pedicle screw fixation was used to treat patients either with a posterior fusion only or in combination with transforaminal lumbar interbody fusion (TLIF), anterior lumbar interbody fusion (ALIF), and direct lateral interbody fusion (D-LIF). Minimal follow-up period accounted for 18 months. Cases with screw loosening were registered assessing association with risk factors using logistic regression. RESULTS: The rate of screw loosening was in positive correlation with the number fused levels and decreasing bone radiodensity. Fusion with a greater load-bearing surface cage was associated with the decrease in rate of pedicle screws loosening. Incomplete reduction in case of spondylolisthesis, bilateral facet joints removal, and laminectomy performed without anterior support favored pedicle screws loosening development. The estimated model classifies correctly 79% of cases with the specificity and sensitivity accounting for 87% and 66% respectively. CONCLUSIONS: The decreasing bone radiodensity in Hounsfield units has a considerable correlation with the rate of pedicle screws loosening. On the other hand, the length of fixation and applied surgical technique including fusion type also have a significant impact on complication rate. Spinal instrumentations should be planned by taking into account all potential risk factors and not characteristics relevant to bone quality assessment alone.

Five-year results of a clinical pilot study utilizing a pedicle-lengthening osteotomy for the treatment of lumbar spinal stenosis.

OBJECTIVE Lumbar spinal stenosis (LSS) is a common condition that leads to significant disability, particularly in the elderly. Current therapeutic options have certain drawbacks. This study evaluates the 5-year clinical and radiographic results of a minimally invasive pedicle-lengthening osteotomy (PLO) for symptomatic LSS. METHODS A prospective, single-arm, clinical pilot study was conducted involving 20 patients (mean age 61.7 years) with symptomatic LSS treated by a PLO procedure at 1 or 2 lumbar levels. All patients had symptoms of neurogenic claudication or radiculopathy secondary to LSS, and had not improved after a minimum 6-month course of nonoperative treatment. Eleven patients had a Meyerding grade I degenerative spondylolisthesis in addition to LSS. Clinical outcomes were measured using the Oswestry Disability Index, Zürich Claudication Questionnaire, 12-Item Short Form Health Survey, and a visual analog scale for back and leg pain. Procedural variables, neurological outcomes, adverse events, and radiological imaging (plain radiographs and CT scans) were collected at the 1.5-, 3-, 6-, 9-, 12-, 24-, and 60-month time points. RESULTS The PLOs were performed through percutaneous incisions, with minimal blood loss in all cases. There were no operative complications. Four adverse events occurred during the follow-up period. Statistically significant improvement was observed in each of the outcome instruments and maintained over the 5-year follow-up period. Imaging studies, reviewed by an independent radiologist, showed no evidence of device subsidence, migration, breakage, or heterotopic ossification. Thin-slice CT scans documented healing of the osteotomy site in all patients at the 6-month time point and an increase of 115% in the mean cross-sectional area of the spinal canal. CONCLUSIONS Treatment of patients with symptomatic LSS with a PLO procedure provided substantial enlargement of the area of the spinal canal and favorable clinical results for both disease-specific and non-disease-specific outcome measures at all follow-up time points out to 5 years. Future research is needed to compare this technique to alternative therapies for LSS.

The Potential Impact of Venobasillar System Morphology and Applied Technique on Epidural Cement Leakage with Percutaneous Vertebroplasty.

BACKGROUND: Bone cement leakage during vertebroplasty is a frequently reported complication with the potential for neural injury. OBJECTIVE: To assess risk factors for epidural cement leakage during vertebroplasty. SETTING: Neurosurgical department of a scientific research institute. STUDY DESIGN: This is a prospective cross-sectional randomized trial. METHODS: Seventy-five patients with intractable pain due to low energy vertebral compression fractures between T11 and L5 were treated with vertebroplasty at 150 vertebral levels. Preoperative computed tomography (CT) scans were utilized to characterize vertebral parameters including the type of nutrient foramina in the posterior vertebral cortex. Following vertebroplasty, distance from the needle tracts to the midline and the presence and type of any epidural cement leakage were determined. Using logistic regression analysis, significant risk factors for cement leakage were determined. RESULTS: A smaller distance between the tip of the needle and the midline and a magistral type of venobasillar system were found to be significant risk factors for epidural cement leakage (P < 0.0001). Use of a bipedicular vs. monopedicular technique did not significantly affect the rate of epidural cement leakage (P = 0.3869). LIMITATIONS: This study is limited because of the relatively small number of patients and the lack of any patients who had clinical consequences as a result of extensive epidural cement leakage. CONCLUSION: The type of venobasillar system should be taken into account when planning a vertebroplasty procedure as a magistral type of venobasillar system is associated with the increased rate of epidural cement leakage. It is important to try and achieve a large distance between the needle tip and the midline, especially when a magistral type of venobasillar system is present, to reduce the risk of epidural cement leakage.

The potential impact of various diagnostic strategies in cases of chronic pain syndromes associated with lumbar spine degeneration.

PURPOSE: To study the possible effects of various diagnostic strategies and the relative contribution of various structures in order to determine the optimal diagnostic strategy in treating patients with noncompressive pain syndromes. STUDY DESIGN: Prospective, nonrandomized cohort study of 83 consecutive patients with noncompressive pain syndromes resistant to repeated courses of conservative treatment. The follow-up period was 18 months. RESULTS: Nucleoplasty was effective in cases of discogenic pain; the consequences related to false positive results of the discography were significant. The most specific criterion was 80% pain relief after facet joint blocks, whereas 50% pain relief and any subjective pain relief were not associated with a significant increase in the success rate. A considerable rate of false negative results was associated with 80% pain relief, whereas 50% pain relief after facet joint blocks showed the optimal ratio of sensitivity and specificity. Facet joint pain was detected in 50.6% of cases (95% confidence interval 44.1%-66.3%), discogenic pain in 16.9% cases (95% confidence interval 9.5%-26.7%), and sacroiliac joint pain in 7.2% cases (95% confidence interval 2.7%-15%). It was impossible to differentiate the main source of pain in 25.3% of cases. CONCLUSION: It is rational to adjust the diagnostic algorithm to the probability of detecting a particular pain source and, in doing so, reduce the number of invasive diagnostic measures to evaluate a pain source. False positive results of diagnostic measures can negatively affect the overall efficacy of a particular technology; therefore, all reasons for the failure should be studied in order to reach an unbiased conclusion. In choosing diagnostic criteria, not only should the success rate of a particular technology be taken into consideration but also the rate of false negative results. Acceptable diagnostic criteria should be based on a rational balance of sensitivity and specificity.

Effects of continuous epidural anesthesia and postoperative epidural analgesia on pain management and stress response in patients undergoing major spinal surgery.

STUDY DESIGN: A prospective, randomized study was used to compare 2 anesthesia/analgesia methods for reconstructive spine surgery. OBJECTIVE: To assess the efficacy and influence of 2 anesthetic methods on clinical outcome and stress response during reconstructive spine surgery. SUMMARY OF BACKGROUND DATA: Pain control is an important goal of the postoperative care after spinal surgery. Some prior studies have suggested that epidural anesthesia with or without postoperative epidural analgesia may blunt the surgical stress response after major surgery. This treatment approach has not been fully investigated for patients undergoing major spinal surgery. We hypothesized that the stress response after major spine surgery would be attenuated by continuous epidural anesthesia/analgesia with ropivacaine, fentanyl, and epinephrine. METHODS: Eighty-five patients were randomly allocated to 2 groups as follows: group E (n = 45) had epidural anesthesia and endotracheal anesthesia with sevoflurane during surgery and continuous epidural analgesia with ropivacaine, fentanyl, and epinephrine after surgery; group G (n = 40) had general anesthesia with sevoflurane and fentanyl and systemically administered opioids after surgery. Patient pain, nausea, mobility, and satisfaction were measured after surgery along with levels of cortisol, glucose, interleukin (IL)-1ß, IL-6, and IL-10 during and after surgery. RESULTS: In group E, there were significantly less pain, less nausea, earlier mobility, and higher satisfaction than those in group G. Group E also experienced significantly less introperative and postoperative blood loss. Group E demonstrated lower levels of glucose, cortisol, IL-1ß, IL-6, and IL-10 during the postoperative period. CONCLUSION: Combined epidural/general anesthesia and postoperative epidural analgesia produced better pain control, less bleeding, and a lower surgical stress response than general anesthesia with postoperative systemically administered narcotic analgesia. This technique deserves further study in the setting of major spinal surgery.

Twelve-month results of a clinical pilot study utilizing pedicle-lengthening osteotomy for the treatment of lumbar spinal stenosis.

OBJECT: Lumbar spinal stenosis (LSS) is a common condition that leads to significant disability, particularly in the elderly. Current therapeutic modalities for LSS have certain drawbacks when applied to this patient population. The object of this study was to define the 12-month postoperative outcomes and complications of pedicle-lengthening osteotomies for symptomatic LSS. METHODS: A prospective, single-treatment clinical pilot study was conducted. A cohort of 19 patients (mean age 60.9 years) with symptomatic LSS was treated by pedicle-lengthening osteotomy procedures at 1 or 2 levels. All patients had symptoms of neurogenic claudication or radiculopathy secondary to LSS and had not improved after a minimum 6-month course of nonoperative treatment. Eleven patients had a Meyerding Grade I degenerative spondylolisthesis in addition to LSS. Clinical outcomes were measured using the Oswestry Disability Index (ODI), Zurich Claudication Questionnaire (ZCQ), 12-Item Short-Form Health Survey (SF-12), and a visual analog scale (VAS). Procedural variables, neurological outcomes, adverse events, and radiological imaging (plain radiographs and CT scans) were collected at the 1.5-, 3-, 6-, 9-, and 12-month time points. RESULTS: The pedicle-lengthening osteotomies were performed through percutaneous approaches with minimal blood loss in all cases. There were no operative complications. Four adverse events occurred during the follow-up period. Clinically, significant improvement was observed in the mean values of each of the outcome scales (comparing preoperative and 12-month values): ODI scores improved from 52.3 to 28.1 (p < 0.0001); the ZCQ physical function domain improved from 2.7 to 1.8 (p = 0.0021); the SF-12 physical component scale improved from 27.0 to 37.9 (p = 0.0024); and the VAS score for leg pain while standing improved from 7.2 to 2.7 (p < 0.0001). Imaging studies, reviewed by an independent radiologist, showed no evidence of device subsidence, migration, breakage, or heterotopic ossification. Thin-slice CT documented healing of the osteotomy site in all patients at the 6-month time point and an increase in the mean cross-sectional area of the spinal canal of 115%. CONCLUSIONS: Treatment of patients with symptomatic LSS with a pedicle-lengthening osteotomy procedure provided substantial enlargement of the area of the spinal canal and favorable clinical results for both disease-specific and non-disease-specific outcome measures at the 12-month time point. Future studies are needed to compare this technique to alternative therapies for lumbar stenosis.

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.