Lumbar herniated disc-endoscopic discectomy treatment

This guideline followed the pattern of a systematic review with evidence collection based on the movement of Evidence-Based Medicine, in which clinical experience is integrated with the ability of critical analysis, rationally applying scientific information, thus improving the quality of medical assistance. We used the structured version of the question synthesized by the P.I.C.O. acronym, in which P stands for patients with a lumbar herniated disc with surgical indication; I for endoscopic lumbar discectomy intervention; C for comparison between microdiscectomy and open discectomy; and O for the outcomes related to the clinical effectiveness and safety. From the structured question, we identified the keywords used as a basis for the evidence search in the sources of data: Medline-PubMed (886 papers) and, after we applied the eligibility criteria (inclusion and exclusion), 25 papers were selected to answer the clinical questions (Appendix I).


INTRODUCTION
Lumbar herniated discs occur when the nucleus pulposus of an intervertebral disc protrudes through a rupture in the fibrous ring surrounding it.Its symptoms include lumbar or lower limb pain, accompanied by numbness and weakness.Permanent severe neurological damages, including foot drop, bladder dysfunc-tion, and cauda equina syndrome may sometimes occur.Lumbar discectomy is considered when there is no serious nerve compression or persistent symptoms that did not respond to conventional treatment.The surgical techniques include open discectomy, microdiscectomy, or minimally-invasive alternatives, using percutaneous endoscopic approaches.The choice of surgical procedure can be influenced by several factors, including the symptoms and signs presented, in addition to the location and size of the prolapsed disc.The full-endoscopic discectomy (ED) is a new type of minimally invasive surgery developed to reduce surgical trauma, accelerate postoperative recovery and maintain the integrity of the normal anatomy of the spinal column 1,2 .The terminology varies quite a lot, with several names to indicate the same procedure, with minimal changes.ED includes two different approaches, basically, with distinct indications and techniques: the transforaminal and the interlaminar 3 .

RESULTS OF THE SELECTED EVIDENCE
Patients with lumbar herniated disc confirmed by clinical symptoms and imaging exams (X-ray and MRI) were randomized into two groups: transforaminal percutaneous endoscopic lumbar discectomy (TPELD) and conventional fenestration discectomy (FD).The exclusion criteria were: (1) LHD associated to other diseases, including neuropathy, metabolic diseases, any heart, lung, liver, or kidney related diseases, or chronic/acute inflammation; (2) multilevel disc herniations; (3) spinal column infections, tumors, discitis or spinal tuberculosis; (4) recurrent disc herniation; and (5) lumbar instability or spondylolisthesis in more than two levels.A total of 48 patients were included in the TPELD group and 58 in the FD group, with an average follow-up time of 16.7 months (12 -25) e 17.3 (12.5 -23.5), respectively for each group.In the TPELD group, compared to the FD group, we found lower blood loss (in ml, 13.8 ± 3.6 vs 87.2 ± 32.3; MD = -74; CI95% -83.2 to -64.8; p<0.01), shorter hospitalization time (days, 7.2 ± 1.6 vs 12.8 ± 3.8; MD = -5; CI95% -5.8 to -4.10; p<0.01), lower risk of complications (ARR = 0.14; CI95% 0.019 to 0.269; NNT = 7, CI95% 4 to 52) in 6 months after the surgery.In TPELD, in comparison with FD, the pain was reduced (VAS) on the legs (p<0.05) and lumbar spine (p<0.05), at the 6-month analysis; however, there was no difference for these comparisons at 12 months.As for the postoperative ODI score, there was no differ-ence between both groups at 6 and 12 months of fol-low0up (all p<0.05).Based on the modified MacNab, at the end of the follow-up, 95.84% of the patients in the TPELD group and 94.82% in the FD group were classified as excellent or good, with no significant difference between both groups (p>0.05). 4(B) (This RCT is not included in the RSs mentioned here.) A total of 1,092 adult patients (<70 years) with symptomatic lumbar herniation was included in a systematic review with a meta-analysis that compared endoscopic discectomy (ED) and open discectomy (OD).Out of the 15 studies assessed in its integrity (search from August 2014), 9 RCTs with sample size ranging from 40 to 240 patients were meta-analyzed.Studies that included patients with acute vertebral fracture, infection, tumor, or rheumatoid arthritis were excluded.The studies included in the meta-analysis were heterogeneous in patient selection, surgery techniques, instruments used, and follow-up time (minimum of 1 year and loss <20% for all studies).The authors observed that the studies had good methodological quality.The instrument used to measure clinical outcomes (primary outcome) was the MacNab criteria ("global perceived effect" or "global improvement").There is no reference to the instrument used to assess the "patient satisfaction", considered a secondary outcome along with intraoperative blood loss and length of hospital stay. 5

(B)
The meta-analysis of the 9 RCTs showed the results below. 5

(B)
EFFECTIVENESS -There was no difference with statistical significance (ED vs OD) • in the "global improvement" (MacNab criteria) between the ED (95.7%) and OD (80% This systematic review of RCTs compared microendoscopic discectomy (MED) with open discectomy (OD) or microdiscectomy (MD), evaluating their effectiveness and safety in patients with symptomatic lumbar herniated disc.Out of the 109 studies analyzed, the authors found only four randomized clinical trials that met the eligibility criteria (Huang et al. 7 , Righesso et al. 8 , Teli et al. 9 and Garg et al. 10 ) and reported the Oswestry Disability Index (ODI) as a result.Three studies compared MED and OD, and one compared OD, MD and MED (three groups).The eligibility criteria were studies that included adult patients with symptoms of sciatic pain, who did not respond to conventional treatment and with no previous lumbar herniated disc surgery.Endoscopic surgery by any method of MED that involved the use of an endoscopic tool was considered a surgical intervention, as well as the comparison between any OD and MD method.All four studies showed significant methodological flaws, especially referring to the low score in the CONSORT questionnaire.No significant differences were observed in the results between conventional microdiscectomy and endoscopic discectomy in the Oswestry Disability Index (ODI) scores in any period of time, thus showing similar effectiveness.However, Teli et al. 9 reported a higher rate of complications in patients who underwent endoscopic discectomy.That study, obviously, has a profound impact on this analysis, being one of the largest randomized series reported (total N = 212). 6

(B)
A total of 8,396 adult patients with symptomatic lumbar herniated disc (39 studies reported in 45 articles) was included in this review, with search until 2008; being six prospective controlled studies (one RCT and five non-randomized; n = 920 [412 transforaminal percutaneous endoscopic lumbar discecto-my (TPELD) versus 508 controls]), two retrospective controlled studies (n = 962 [325 transforaminal percutaneous endoscopic lumbar discectomy versus 637 controls] and 31 before and after studies (n = 6.514).The inclusion and exclusion criteria varied between the studies (often not clearly described).Thirty-six studies specified radiculopathy in inclusion criteria.In most studies, the patients received some kind of conservative preoperative treatment for a few months.The duration of symptoms varied; some included all types of hernia and other just some specific types.Therefore, several techniques were used (including intradiscal and intracanal), as well as different instruments.The follow-up time ranged from six weeks to 108 months.Sixteen studies had an average follow-up of over two years.The studies included in this review were heterogeneous in patient selection, surgical indication, surgery techniques, follow-up time and outcome measures.The authors observed that the studies had poor methodological quality.The studies used different instruments (validated and not validated) to measure the results.Pain was measured by the Visual Analog Scale (VAS) or visual numeric scale.The functional status was measured by the Oswestry Disability Index (ODI) or Roland Morris Disability Scale.The ODI measures the degree of disability in a person with lumbar pain.The index score ranges from 0 to 100, 0 indicating no disability and 100 maximum disability.The "global perceived effect" was measured using the MacNab score or the percentage of patients with improvement.Patient satisfaction was generally reported using a Likert scale .In two series of cases included, the intervention was the "endoscopic laser foraminoplasty" (n = 250).None of the studies included was designed to assess adverse events. 11(B) A review of the eight studies with a control group showed the results below.EFFECTIVENESS OF TPELD • leg pain (VAS) -an improvement of 88% (65%-89%) -7 studies, n = 1558, • lumbar pain (VAS) -an improvement of 74% (13%-84%) -5 studies, n = 1401, • "global improvement" (MacNab criteria) -an improvement of 85% (72%-94%) -15 studies (n = 2,544), • functional state (ODI) -an improvement of 83% (74%-90%) -3 studies, n = 624, • returned to work -90% (67%-95%) -5 studies, n = 757, • median rate of recurrence -1.7% (0%-12%) -13 studies, n = 2,612, • median rate of reoperation -7% (0-27%) -28 studies (n = 4.135).SAFETY OF TPELD • median rate complications -2.8% (0%-40%) -28 studies, n = 6,336, This study concluded that the results on the effectiveness of transforaminal endoscopic surgery were poor and did not provide valid information to support or refute its use in patients with a symptomatic lumbar herniated disc. 11(B)  This systematic review assessed the effectiveness and safety of the percutaneous endoscopic lumbar discectomy (PELD) in the treatment of recurrent lumbar herniated discs (rLHD), second surgery.Three controlled studies were included (an RCT, one non-randomized CT and a retrospective cohort), in addition to five studies with no control group (before and after [2] and observational retrospective [3]), with searches in publications from 2002 to July 2015.Patients with recurrence confirmed by imaging exams with the failure of the conservative treatment and a pain-free interval of six weeks were included in the studies.The main exclusion criteria for PELD were: sequestrated or calcified discs, lumbar stenosis greater than moderate, instability of the spinal column, spondylolisthesis, cauda equina syndrome, and severe neurological deficit.The methodological rigor and scientific quality of the studies were considered in the analysis and conclusion of this review.In order to compare PELD and open discectomy (OD), a meta-analysis was carried out, including the three controlled studies, whose quality was considered high after the analysis.The quality of the five non-controlled studies was considered moderate/high. 12(B) An assessment of the eight studies (n = 475; three controlled and five non-controlled ) included in this review showed the following results, expressed in mean and range (min-max).

DISCUSSION
The results of this review showed that the bleeding and length of hospital stay were lower with the percutaneous lumbar discectomy in comparison with MD/OD.The differences were small and did not reach the standard threshold for clinically significant differences in the assessment of outcomes, such as: global improvement (McNab criteria), function improvement (Oswestry Disability Index), recurrences, reoperations, and complications (clinical outcomes).A RCT (Teli et al. 9 ) included in a systematic review (Smith et al. 6 ) and, therefore, not separately described in this review, showed an increase in the number of complications; however, another RCT (Pan Z et al. 4 ) showed a reduction.Another study that showed a decrease in the number of complications assessed the composite outcome and, when the analysis was carried out separately, by outcome (infection and dural tears), it did not find any differences. 12(B) It is important to consider that this review grouped different surgical and instrumental techniques, according to the type of lumbar disc herniation.For this review, the results of the meta-analysis with high heterogeneity (I 2 >80%) were not considered consistent.The analysis was deemed to be consistent when it had low heterogeneity (R 2 = 0%) for the outcomes: recurrence, reoperation, improvement in functional status.The general opinion of the authors, reported in the discussion/conclusion sections of most studies, is that the results for endoscopic microdiscectomy are comparable to that of a standard microdiscectomy.

Returned studies
The literature review was carried out until December 10, 2016 in the databases Medline/PubMed and Cochrane Library.The studies were identified in terms of MeSH vocabulary and free text (Table 1).
The evidence used was retrieved by the following steps: elaboration of the clinical question, structuring of the question, search for evidence, presentation of results, and recommendations.Inclusion criteria for the selected papers The selection of the studies and the evaluation of the titles and abstracts obtained from the search strategy in the databases consulted were independently and blindly conducted by two researchers with expertise in the development of systematic reviews, in total accordance with the inclusion and exclusion criteria established and described in the PICO.Finally, the studies with potential relevance were separated.

According to the designs of the studies
Systematic Reviews (SRs) were included, with or without meta-analysis that did not include the same studies, and RCTs published a posteriori.
The evidence retrieved was selected based on a critical assessment that used the Amstar (A Measurement Tool to Assess Reviews) tool for SRs and the Jadad 14 and Grade 15 discriminatory instruments (scores) for the RCTs.
The Type II Error was not used in the selection of RCTs in order to avoid greater limitation.

Language
Studies available in Portuguese, English, Italian or Spanish were included.

According to the publication
Only studies with texts available in its entirety were considered for critical evaluation.

Method for critical evaluation
From the databases, after the initial critical evaluation, were selected: Medline/PubMed (5 studies), Cochrane Library (0) (Appendix II).
The papers considered for complete reading were critically evaluated following the inclusion and exclusion criteria, based on study performance, PICO, language and availability of the text in its entirety.
Out of the five papers considered for critical evaluation, none was excluded for not being complete.
Amstar 13 was used to evaluate the quality of the systematic reviews.This tool provides a global quality rating on a scale from 0 to 11, in which 11 represents a review of the highest quality.Quality categories were determined as follows: low (0 to 3 score), medium (4 to 7 score) and high (8 to 11 score).SRs of low and medium quality were excluded (Appendix III) When, after the inclusion and exclusion criteria were applied, the evidence selected was classified as Randomized Controlled Trial (RCT), it was subjected to a suitable critical evaluation check-list Table 2).The critical evaluation of RCT allows to classify it according to the Jadad score 14 , considering Jadad trials < 3 (three) as inconsistent, and those with score ≥ 3 (three) consistent.
During the critical evaluation, the Grade 15 (Grading of Recommendations Assessment, Development and Evaluation) discriminatory instrument was also applied, using evidence of high and moderate quality (Table 3).

Presentation of the results of the evidence selected
The results regarding the intervention considered in the clinical question will be exposed individually, by means of the following items: clinical question, number of selected works (according to the criteria of inclusion), main reasons for exclusion and synthesis of the evidence available.
References related to studies included and excluded will be arranged in the item References and the reasons for exclusion in Appendix IV.
For results with available evidence, the population, intervention, outcomes, presence or absence of benefits and/or harmful effects, and controversy will be specifically defined whenever possible.
Matters related to costs will not be included in the results, and the outcomes considered will be limited to the clinical effectiveness and safety of the interventions.

Recommendations
The recommendations will be elaborated by the authors of the review, with the initial characteristic of synthesis of evidence, and will subject to validation by all authors who participated in creating the Guideline.
The level of recommendation used comes directly from the power available in the studies included in Oxford 16 and the use of the Grade system 15 .Amstar (a measurement tool to assess reviews) Is endoscopic lumbar discectomy effective and safe when compared with microdiscectomy and open discectomy for patients with lumbar herniated disc and surgical indication?Structured question P -Patients with a lumbar herniated disc with surgical indication I -Endoscopic lumbar discectomy C -Microdiscectomy or open discectomy O -Outcomes related to clinical effectiveness and safety Methodology for evidence search PubMed-Medline #1 − (Intervertebral Disk Displacement OR Disc, Herniated OR Discs, Herniated OR Disk, Herniated OR Disks, Herniated) AND (Surgical Procedures, Endoscopic OR Surgical Procedure, Endoscopic OR Surgical Endoscopy OR Endoscopy OR endoscopic OR Percutaneous Endoscopic Discectomy OR endoscopic discectomy) #2 − (Diskectomies OR Discectomy OR Discectomies OR Diskectomy) AND (Surgical Procedures, Endoscopic OR Surgical Procedure, Endoscopic OR Surgical Endoscopy OR Endoscopy OR Percutaneous Endoscopic Discectomy OR endoscopic discectomy) #1 OR #2

No ITT = analysis by intention to treat / Jadad = 3 /
Sample size calculation = There was none Papers after duplicates were excluded (

TABLE 1 -
NO. OF PAPERS RETURNED FROM THE SEARCH METHODOLOGY USED IN EACH OF THE SCI-

TABLE 2 -
GUIDE FOR CRITICAL EVALUATION OF RAN-DOMIZED CONTROLLED TRIALS

TABLE 3 -
DESCRIPTIVE TABLE OF THE BIASES IN THERAPEUTIC STUDIES