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KSR Number: KSRA12084

Percutaneous endoscopic lumbar discectomy for recurrent lumbar disc herniation

Risk of Bias Assessment

Overall summary: Risk of bias unclear

Bottom Line

The evidence indicated that operative time, blood loss and complication rates were significantly reduced with percutaneous endoscopic lumbar discectomy in patients with recurrent lumbar disc herniation in comparison with open lumbar microdiscectomy. Whereas, the difference between the treatment groups were similar in terms of pain reduction, global perceived effect (MacNab score), re-operation and recurrence rate. Hence, percutaneous endoscopic lumbar discectomy could be used as an alternative to the conventional procedure in the treatment of recurrent lumbar disc herniation. Search terms were provided, but a full search strategy was not reported, therefore it was not possible to judge if all relevant studies had been retrieved. Further high-quality randomised controlled trials were required to address the present review question.

Risk of Bias Assessment

Overall summary Risk of bias unclear

Unclear

Search terms were provided but a full search strategy was not reported, therefore it was not possible to judge if all relevant studies had been retrieved.

A. Did the interpretation of findings address all of the concerns identified in Domains 1 to 4? No information
B. Was the relevance of identified studies to the review's research question appropriately considered? Probably yes
C. Did the reviewers avoid emphasizing results on the basis of their statistical significance? Probably yes
Risk of bias in the review Unclear

Details of Review

Number of studies 8
Number of participants 475
Last search date July 2015
Review type Intervention
Objective To evaluate the effectiveness of percutaneous endoscopic lumbar discectomy in the treatment of recurrent lumbar disc herniation and to present its indications and techniques.
Population Patients with recurrent lumbar disc herniation (verified by radiological examination).

The studies in which primary lumbar disc herniation operated by percutaneous endoscopic lumbar discectomy were excluded.
Interventions Percutaneous endoscopic lumbar discectomy.

Studies in which treatment with percutaneous endoscopic transforaminal discectomy or percutaneous endoscopic interlaminar discectomy were included.
Comparator Open lumbar microdiscectomy and conventional microsurgical.
Outcome Leg pain and back pain (measured using visual analogue scale), functional status (assessed using Oswestry disability index), global perceived effect (McNab score/the percentage of patients satisfactory), and other outcomes (recurrences, complications, re-operation), dural tear incidence, operation time, blood loss and hospital stay.
Study design Prospective randomised controlled trial, retrospective controlled studies, prospective cohort studies and observational retrospective studies.

The literature of review were excluded.

Results

The mean overall operative time of percutaneous endoscopic lumbar discectomy (PELD) for recurrent lumbar disc herniation (rLDH) was 47.37 minutes (24 to 79.06; five studies, n=177 patients). The mean overall improvement of leg pain (assessed using visual analogue scale (VAS) score) was 66.92% (50.6% to 89.87%; seven studies, n=457 patients), back pain (VAS score) 54.91% (29% to 67.95%; five studies, n=339 patients), Oswestry disability index (ODI) was 60.9% (40.7% to 75%; four studies, n=111 patients) and the global perceived effect (MacNab score) 75.77% (60% to 95%; five studies, n=391 patients).

The mean overall complications rate was 4.89% (0% to 9.76%; five studies, n=177 patients), re-operation rate was 3.66% (2.33% to 4.8%; three studies, n=110 patients), recurrence rate was 6.3% (4% to 10%; six studies, n=414 patients) and total dural tear rate was 0.1% (0% to 4.9%, seven studies, n=213 patients).

Pooled analysis of three trials reported a statistically significant reduction in the operation time in patients who received PELD (when compared to those who received open microdiscectomy (OD) (mean difference (MD) = -59.08, 95% confidence interval (CI) -98.03 to -20.13; n=197 patients). Similarly, a statistically significant reduction in blood loss (MD = -161.73, 95% CI -418.46 to 95.01; two studies, n=143 patients) and hospital stay (MD = -6.49, 95% CI -13.83 to 0.84; two studies, n=97 patients) were observed in the PELD group than in the OD group.

No significant difference was observed between PELD and OD groups in terms of improvement in back pain (VAS score) (MD = -0.28, 95% CI -3.90 to 3.33; two studies, 141 patients), improvement in leg pain (VAS score) (MD=2.03, 95% CI -1.38 to 5.44), ODI (MD = -3.62, 95% CI -13.93 to 6.70; two studies, 141 patients) and incidence of recurrence (risk ratio (RR) = 0.53, 95% CI 0.13 to 2.22; three trials, n=184 patients).

Summary estimates from three studies showed a significant reduction in the incidence of complications in the PELD group (RR=0.24, 95% CI 0.08 to 0.71; n=197 patients) compared to the OD group.

Full Risk of Bias Assessment

The eligibility criteria were well described and appeared appropriate to address the present review question. Studies with more than 10 cases were included and found to be appropriate. No restriction was reported based on the sources of information.

1.1 Did the review adhere to pre-defined objectives and eligibility criteria? Probably yes
1.2 Were the eligibility criteria appropriate for the review question? Probably yes
1.3 Were eligibility criteria unambiguous? Probably yes
1.4 Were all restrictions in eligibility criteria based on study characteristics appropriate (e.g. date, sample size, study quality, outcomes measured)? Probably yes
1.5 Were any restrictions in eligibility criteria based on sources of information appropriate (e.g. publication status or format, language, availability of data)? Probably yes
Concerns regarding specification of study eligibility criteria Low

MEDLINE, EMBASE, Web of Science and Cochrane databases were searched for relevant studies. The reference lists of eligible studies and relevant reviews were checked for additional relevant studies. Search terms were provided, but a full search strategy was not reported. The searches were not restricted to date, publication format or language. Two review authors were independently involved in the study selection process and any disagreement between them was resolved by discussion with the corresponding author.

2.1 Did the search include an appropriate range of databases/electronic sources for published and unpublished reports? Probably yes
2.2 Were methods additional to database searching used to identify relevant reports? Probably yes
2.3 Were the terms and structure of the search strategy likely to retrieve as many eligible studies as possible? No information
2.4 Were restrictions based on date, publication format, or language appropriate? Probably yes
2.5 Were efforts made to minimise error in selection of studies? Yes
Concerns regarding methods used to identify and/or select studies Unclear

Two review authors were independently involved in the data extraction process and re-checked by one author. Sufficient study characteristics appeared to have been extracted to allow interpretation of the results and study results were appropriately collected for the synthesis. Methodological quality of the included controlled trials and non-control studies were assessed according to the 12 criteria and instructions recommended by the Cochrane Back Review Group and modified 5-point assessment score respectively. Two review authors were independently involved in the risk of bias assessment and any disagreements were resolved by discussion with the corresponding author.

3.1 Were efforts made to minimise error in data collection? Yes
3.2 Were sufficient study characteristics considered for both review authors and readers to be able to interpret the results? Probably yes
3.3 Were all relevant study results collected for use in the synthesis? Probably yes
3.4 Was risk of bias (or methodological quality) formally assessed using appropriate criteria? Probably yes
3.5 Were efforts made to minimise error in risk of bias assessment? Yes
Concerns regarding methods used to collect data and appraise studies Low

The synthesis included all eligible studies. The method of analysis was explained and appeared to be appropriate. There was significant evidence of heterogeneity for five outcomes (operation time, blood loss, hospital stay, back pain and leg pain). Appropriate attempts were not made to explore the possible sources of heterogeneity due to less numbers of studies for each outcome (two to three studies). Publication bias was not feasible due to the low number of studies included for each comparison. The quality of individual studies was considered in the synthesis.

4.1 Did the synthesis include all studies that it should? Probably yes
4.2 Were all pre-defined analyses reported or departures explained? Probably yes
4.3 Was the synthesis appropriate given the degree of similarity in the research questions, study designs and outcomes across included studies? Probably yes
4.4 Was between-study variation minimal or addressed in the synthesis? Probably yes
4.5 Were the findings robust, e.g. as demonstrated through funnel plot or sensitivity analyses? Probably yes
4.6 Were biases in primary studies minimal or addressed in the synthesis? Probably yes
Concerns regarding synthesis and findings Low

Keywords

  • Diskectomy, Percutaneous
  • Endoscopy
  • Intervertebral Disc Displacement
  • Length of Stay
  • Lumbar Vertebrae
  • Operative Time
  • Pain
  • Pain Measurement
  • Recurrence