Orthopedics

Review Article 

Surgical Treatment of Recurrent Lumbar Disk Herniation: A Systematic Review and Meta-analysis

Remi M. Ajiboye, MD; Austin Drysch, BS; Gina M. Mosich, MD; Akshay Sharma, BA; Sina Pourtaheri, MD

Abstract

Consensus is lacking regarding optimal surgical treatment of recurrent lumbar disk herniation. A systematic search of multiple databases was conducted for studies evaluating outcomes after treatment for recurrent lumbar disk herniation. Treatment options included decompression surgeries and fusion surgeries. Although fusion surgeries eliminated re-recurrence of disk herniation, this coincided with higher incidences of complications and reoperation. Decompression surgeries and fusion surgeries both resulted in improvements in Japanese Orthopaedic Association, Oswestry Disability Index, and visual analog scale back and leg scores postoperatively (P<.05). The complication risk profiles of decompression surgeries and fusion surgeries must be balanced with the risk of disk herniation re-recurrence, as both procedures lead to improvements in functional outcomes. [Orthopedics. 2018; 41(4):e457–e469.]

Abstract

Consensus is lacking regarding optimal surgical treatment of recurrent lumbar disk herniation. A systematic search of multiple databases was conducted for studies evaluating outcomes after treatment for recurrent lumbar disk herniation. Treatment options included decompression surgeries and fusion surgeries. Although fusion surgeries eliminated re-recurrence of disk herniation, this coincided with higher incidences of complications and reoperation. Decompression surgeries and fusion surgeries both resulted in improvements in Japanese Orthopaedic Association, Oswestry Disability Index, and visual analog scale back and leg scores postoperatively (P<.05). The complication risk profiles of decompression surgeries and fusion surgeries must be balanced with the risk of disk herniation re-recurrence, as both procedures lead to improvements in functional outcomes. [Orthopedics. 2018; 41(4):e457–e469.]

Lumbar disk herniation is a fairly common condition, with a reported prevalence of 1% to 3%.1 Following surgical treatment of lumbar disk herniation, recurrent lumbar disk herniation (RLDH) is estimated to occur in 5% to 11% of patients, with reoperation reported for up to 24% of these patients.2–6 Reoperation for RLDH is often performed when pain relief cannot be achieved following conservative measures, although revision surgery is not without additional challenges. The presence of scar tissue during reoperation increases the risk of neurological injury and dural tear.7 Further, there is also a potential for segmental instability with additional removal of disk material, leading some surgeons to believe fusion is necessary during revision surgery for RLDH.8,9

Currently, consensus is lacking in the literature and controversy exists regarding the optimal surgical treatment of RLDH. Geography, practice type, fellowship training, and annual case volume are factors that have been reported to influence surgeons' preference for surgical treatment of RLDH.10 Given these findings, a systematic review and meta-analysis of the literature was performed to help patients and surgeons make an informed decision on the optimal surgical treatment of RLDH. Specifically, the goal of this study was to compare the surgical treatment options for RLDH in relation to complications, re-recurrence of disk herniation, reoperation, and functional outcomes.

Materials and Methods

Search Strategy

A systematic search of Medline, Embase, Cochrane Reviews, Scopus, and Web of Science was performed to identify studies that reported on the clinical and/or functional outcomes of surgical treatment of RLDH. The search terms used included “disc herniation,” “lumbar disc herniation,” “lumbar disc re-herniation,” “recurrent lumbar disc herniation,” “discectomy,” “microdiscectomy,” and “fusion.” The search strategy was developed to include all study designs. English-language full-text manuscripts or abstracts were reviewed. Following review of all relevant reports, the references of articles selected for review were further assessed to identify studies that were not captured in the initial database search.

Selection of Studies

Studies that reported on clinical and/or functional outcomes following surgical treatment of RLDH at the same level were included. Studies on nonoperative management of RLDH were excluded. Case reports and non–English-language studies were also excluded.

Outcome Measures

Surgical treatment of RLDH was classified as decompression surgery (DS) or fusion surgery (FS). Decompression surgery was further subdivided into open diskectomy (OD) or endoscopic diskectomy (ED), whereas FS was further subdivided into posterolateral fusion (PLF) or posterior interbody fusion (PIF). Primary outcome measures included clinical outcomes (eg, dural tear, wound infection, neurological complication, re-recurrence of disk herniation, and reoperation) as well as functional outcome (eg, the Japanese Orthopaedic Association [JOA] score, the Oswestry Disability Index [ODI] score, and the visual analog scale [VAS] scores for back and leg pain).

Data Extraction

Two of the authors (R.M.A., A.D.) reviewed and extracted data from studies that fulfilled all inclusion and exclusion criteria. The following variables were extracted from each study: year of study, type of study, level of evidence, demographic data, follow-up time, type of surgery, complications (eg, dural tear, wound infection, and neurological complication), re-recurrence of disk herniation, reoperation, and functional outcome measures (eg, JOA score, ODI score, and VAS scores for back and leg pain).

Assessment of Level of Evidence and Methodological Quality of the Studies

Two of the authors (R.M.A., S.P.) conducted a quality assessment for each of the studies selected for final analysis. Level of evidence ratings were assigned to the studies using the criteria set forth by Wright et al.11 Quality assessment of all of the selected reports was performed by using the 12-point Methodological Index for Non-randomized Studies criteria (Table 1). These criteria have been previously reported to have high test–retest, external and internal validity, and interobserver reliability.42 The risk of bias of comparative studies was assessed using the Cochrane Back Review Group tool (Tables 23).43 If a study met at least 6 of the 12 criteria, the study was labeled as low risk of bias. If 5 or fewer of the 12 criteria were met, the study was labeled as high risk of bias. For non-comparative studies, risk of bias was assessed using a modified 5-point assessment score as previously described.44 Inconsistencies in methodologic quality assessment were reconciled through discussion with a third author (A.D.).

Level of Evidence Ratings and Quality Assessment Using the 12-Point Methodological Index for Non-randomized Studies CriteriaaLevel of Evidence Ratings and Quality Assessment Using the 12-Point Methodological Index for Non-randomized Studies Criteriaa

Table 1:

Level of Evidence Ratings and Quality Assessment Using the 12-Point Methodological Index for Non-randomized Studies Criteria

Risk of Bias and Quality Assessment of the Comparative Studies

Table 2:

Risk of Bias and Quality Assessment of the Comparative Studies

Risk of Bias and Quality Assessment of the Noncomparative Studies

Table 3:

Risk of Bias and Quality Assessment of the Noncomparative Studies

Data Analysis

The data were analyzed using the random effects model with inverse variance weighting. Meta-analyses and forest plots were constructed using the statistical software Review Manager (RevMan; version 5.3; Cochrane, London, England). Summary effects and 95% confidence intervals (CIs) were the primary summary measures. Individual studies were compared via 95% CIs and forest plots. Meta-analysis was completed to determine the incidence of dural tear, wound infection, neurological complication, re-recurrence of disk herniation, and reoperation following each surgical treatment modality. Effect incidence was determined by dividing the number of patients noted with a given variable of interest by the total patient cohort size in each study. Furthermore, meta-analysis was used to compare changes between pre- and postoperative JOA, ODI and VAS back and leg scores. Heterogeneity was evaluated between individual studies with a Q statistic and I2 value for each meta-analysis. As described by DeLong et al,45I2 heterogeneity less than 25% generally indicates consistent results and homogeneous studies, whereas 25% to 75% indicates moderate heterogeneity and greater than 75% indicates severe heterogeneity.

Results

Studies

Overall, the initial search yielded 1734 citations, of which 1658 were excluded from screening of the abstracts. Seventy-six studies were screened, with 42 being excluded because they described nonoperative management of RLDH or did not report on clinical and functional outcomes of RLDH. Thirty-four studies fulfilled all inclusion and exclusion criteria and were included in this systematic review (Figure 1).

Flowchart of included studies. Abbreviation: rLDH, recurrent lumbar disk herniation.

Figure 1:

Flowchart of included studies. Abbreviation: rLDH, recurrent lumbar disk herniation.

Five of the studies were comparative studies on different surgical techniques for the treatment of RLDH. One study compared OD, PIF, and PLF, while 3 studies compared OD with ED. Another study compared OD with PLF. The remaining 29 studies included in this systematic review were noncomparative studies.

Quality Assessment of Included Studies

All studies were published as level II, III, or IV evidence (Table 1). The Methodological Index for Non-randomized Studies scores of the studies ranged from 8 to 19 (average, 12.6; SD, 3.4) (Table 1). All studies included in this review were of good methodologic quality with low risk of bias (Tables 23).

Demographics

The number of patients ranged from 6 to 262 patients per study. The reported mean patient age ranged from 39 to 61.2 years. The mean follow-up time ranged from 4.5 to 146.8 months (Table 4).

Study Characteristics

Table 4:

Study Characteristics

Clinical Outcomes of Decompression Versus Fusion Surgery

The incidence of dural tear was 6.1% (95% CI, −35.6% to 47.8%) for DS compared with 5.3% (95% CI, −35.3% to 4.6%) for FS. The incidence of infection was 0.6% (95% CI, −16.4% to 17.6%) for DS compared with 4.7% (95% CI, −31.1% to 40.6%) for FS (Table 5). The incidence of neurological complications was 1.9% (95% CI, −19.2% to 23.0%) following DS compared with 5.3% (95% CI, −35.4% to 45.9%) following FS. The incidence of re-recurrent disk herniation was 5.2% (95% CI, −37.0% to 47.5%) following DS compared with 0.0% (95% CI, −16.2% to 16.2%) following FS (Table 5). The incidence of reoperation was 5.4% (95% CI, −34.5% to 44.8%) following DS compared with 12.1% (95% CI, −54.3% to 78.5%) following FS (Table 5).

Effect Incidence of Clinical Outcomes Based on Type of Surgery

Table 5:

Effect Incidence of Clinical Outcomes Based on Type of Surgery

Endoscopic Diskectomy

The incidence of dural tear following ED was 3.2% (95% CI, −27.3% to 34.0%), whereas the incidence of infection and neurological complication were 0.0% (95% CI, −13.7% to 13.4%) and 0.0% (95% CI, −12.3% to 12.3%), respectively (Table 5). Following ED, the incidence of disk herniation re-recurrence was 5.3% (95% CI, −35.0% to 44.7%) and the incidence of reoperation was 2.5% (95% CI, −29.4% to 34.4%) (Table 5).

Open Diskectomy

Following OD, the incidence of dural tear was 10.8% (95% CI, −50.2% to 71.8%) and the incidence of infection was 1.7% (95% CI, −21.2% to 24.6%) (Table 5). The incidence of neurological complication was 3.4% (95% CI, −24.7% to 31.6%), and the incidence of disk herniation re-recurrence was 5.2% (95% CI, −36.1% to 46.5%) (Table 5). Following OD, the incidence of reoperation was 7.8% (95% CI, −39.6% to 55.1%) (Table 5).

Posterolateral Fusion

Following PLF, the incidence of dural tear was 8.9% (95% CI, −49.1% to 66.9%) and the incidence of infection was 2.8% (95% CI, −28.3% to 33.9%) (Table 5). The number of studies was insufficient to calculate the frequency of neurological complication, disk herniation re-recurrence, and reoperation following PLF.

Posterior Interbody Fusion

Following PIF, the incidence of dural tear was 4.3% (95% CI, −31.3% to 39.8%) and the incidence of infection was 5.5% (95% CI, −32.3% to 43.3%) (Table 5). The incidence of neurological complication was 6.0% (95% CI, −38.2% to 50.2%), and the incidence of disk herniation re-recurrence was 0.0% (95% CI, −16.3% to 16.3%) (Table 5). Following PIF, the incidence of reoperation was 12.4% (95% CI, −54.3% to 79.2%) (Table 5).

Functional Outcomes of Decompression Versus Fusion Surgery

Decompression surgery and FS both resulted in improvements in JOA, ODI, and VAS back and leg scores postoperatively: DS=+12.95, (JOA: P<.00001), −38.46 (ODI: P<.00010), −3.88 (VAS back: P=.00100), and −5.66 (VAS leg: P<.00001); and FS=+14.26 (JOA: P<.00001), −28.33 (ODI: P=.05000), −5.32 (VAS back: P<.00001), and −6.34 (VAS leg: P<.00001) (Table 6; Figures 29).

Meta-analysis of Changes Between Pre- and Postoperative Functional Outcome Scores Based on Type of Surgery

Table 6:

Meta-analysis of Changes Between Pre- and Postoperative Functional Outcome Scores Based on Type of Surgery

Preoperative (Pre-op) to postoperative (Post-op) improvement of Japanese Orthopaedic Association score following fusion surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Figure 2:

Preoperative (Pre-op) to postoperative (Post-op) improvement of Japanese Orthopaedic Association score following fusion surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Preoperative (Pre-op) to postoperative (Post-op) improvement of Japanese Orthopaedic Association score following decompression surgery. Abbreviations: CI, confidence interval; IV, inverse variance; NF, nonfusion.

Figure 3:

Preoperative (Pre-op) to postoperative (Post-op) improvement of Japanese Orthopaedic Association score following decompression surgery. Abbreviations: CI, confidence interval; IV, inverse variance; NF, nonfusion.

Preoperative (Pre-op) to postoperative (Post-op) improvement of Oswestry Disability Index score following fusion surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Figure 4:

Preoperative (Pre-op) to postoperative (Post-op) improvement of Oswestry Disability Index score following fusion surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Preoperative (Pre-op) to postoperative (Post-op) improvement of Oswestry Disability Index score following decompression surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Figure 5:

Preoperative (Pre-op) to postoperative (Post-op) improvement of Oswestry Disability Index score following decompression surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Preoperative (Pre-op) to postoperative (Post-op) improvement of visual analog scale back score following fusion surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Figure 6:

Preoperative (Pre-op) to postoperative (Post-op) improvement of visual analog scale back score following fusion surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Preoperative (Pre-op) to postoperative (Post-op) improvement of visual analog scale back score following decompression surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Figure 7:

Preoperative (Pre-op) to postoperative (Post-op) improvement of visual analog scale back score following decompression surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Preoperative (Pre-op) to postoperative (Post-op) improvement of visual analog scale leg score following fusion surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Figure 8:

Preoperative (Pre-op) to postoperative (Post-op) improvement of visual analog scale leg score following fusion surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Preoperative (Pre-op) to postoperative (Post-op) improvement of visual analog scale leg score following decompression surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Figure 9:

Preoperative (Pre-op) to postoperative (Post-op) improvement of visual analog scale leg score following decompression surgery. Abbreviations: CI, confidence interval; IV, inverse variance.

Endoscopic Diskectomy

Following ED, mean decrease in ODI, VAS back, and VAS leg scores compared with preoperative values was 28.67 (95% CI, 14.69 to 42.66; P<.00001), 3.05 (95% CI, 1.70 to 4.40; P<.00001), and 5.70 (95% CI, 5.38 to 6.01; P<.00001), respectively (Table 6). The number of studies was insufficient to calculate the mean improvement of JOA scores.

Open Diskectomy

Following OD, mean JOA score improved by 12.95 (95% CI, 10.17 to 15.75; P<.00001) compared with preoperative values, whereas mean ODI and VAS back scores decreased by 53.12 (95% CI, 38.39 to 67.86; P=.00600) and 4.76 (95% CI, 0.06 to 9.47; P=.05000), respectively (Table 6). The number of studies was insufficient to calculate the mean improvement of VAS leg scores.

Posterolateral Fusion

Following PLF, the mean improvement in JOA scores compared with preoperative values was 14.07 (95% CI, 8.49 to 19.66; P<.00001) (Table 6). The number of studies was insufficient to calculate the mean improvement of ODI, VAS back, and VAS leg scores.

Posterior Interbody Fusion

Following PIF, the mean improvement in JOA score was 15.26 (95% CI, 13.87 to 16.65; P<.00001) compared with preoperative values. Mean ODI, VAS back, and VAS leg scores decreased 28.33 (95% CI, 0.46 to 56.21; P=.05000), 5.32 (95% CI, 3.94 to 6.69; P<.00001), and 6.34 (95% CI, 4.62 to 8.07; P<.00001), respectively (Table 6).

Discussion

Recurrent lumbar disk herniation is estimated to occur in 5% to 11% of patients, with reoperation reported for up to 24% of these patients.2–6 Currently, there is a lack of consensus in the literature regarding the optimal surgical treatment of RLDH and whether DS alone is sufficient or if there is added benefit or harm to performing DS and FS. Given the lack of prospective and comparative studies in the current literature, a systematic review and meta-analysis was performed to better address this issue to guide surgical decision-making. In this study, the authors found that there is a tremendous amount of variability regarding complications, re-recurrence of lumbar disk herniation, and reoperations in patients undergoing DS or FS for RLDH. However, DS and FS both lead to improvements in functional outcomes as measured by JOA, ODI, and VAS back and leg scores postoperatively.

Reoperation for RLDH is theoretically associated with increased complications and injury to the neural elements because of the formation of scar tissue and potential loss of normal anatomic landmarks. In this study, the incidence of dural tears was noted to be 6.1% for DS compared with 5.3% for FS. These numbers are in line with the literature, which reports an estimated incidence of 4% to 10% in revision cases.7,21,30,34,35 The incidence of neurological complications was 1.9% following DS compared with 5.3% following FS. Nerve root retraction during placement of an interbody device and pedicle screw malposition have been implicated as factors that lead to nerve injury following lumbar fusion surgery.46–48

The incidence of infection following spine surgery is estimated to range from almost less than 1% to 6%.49–54 For lumbar disk herniation surgery, infection rates of approximately 0.1% to 4% have been reported, with variation based on type of procedure and patient factors.51,52,54 Procedures involving placement of instrumentation have been theorized to carry a higher risk of infection because the surface layer of these implants could serve as a nidus for bacterial growth. Additionally, prolonged operative time and perioperative surgical complications have also been implicated as risk factors for infections.55 In this study, the incidence of infection was 4.7% for FS compared with 0.6% for DS.

Re-recurrent lumbar disk herniation poses a challenging clinical scenario, and there is currently no clinical guideline or consensus on its optimal surgical management. This study found the incidence of re-recurrent disk herniation to be 5.2% for DS compared with 0.0% for FS. On the other hand, the incidence of reoperation was 5.4% following DS compared with 12.1% following FS. In fusion procedures, motion in a diseased disk segment is eliminated, resulting in less mechanical stress at the disk space. In addition, a near-total diskectomy is often performed, which results in less opportunity for disk re-herniation. As such, procedures involving DS are theoretically at a higher risk of re-herniation because motion is preserved. Despite the decreased chance for re-herniation associated with FS, these procedures are not without complications. In this study, the primary reasons for reoperation following FS included implant complications, pseudarthrosis, and adjacent segment disease.56–58 Conversely, the primary reason for reoperation following DS was same-level re-herniation.59–61 As such, the risk of disk re-herniation associated with motion-preserving procedures must be weighed against the risk of implant-related complications, pseudarthrosis, and adjacent segment disease associated with fusion procedures.

Finally, both DS and FS techniques resulted in improvements in all functional outcome scores evaluated in this study, which included JOA, ODI, and VAS back and leg pain scores. This implies that surgical intervention for recurrent lumbar disk herniation leads to improved outcomes regardless of which surgical option is performed. The complications profile, risk of herniation, and risk of reoperation of a given procedure need to be considered when deciding which revision surgical intervention will be most effective for an individual patient.

Limitations

There were limitations inherent to this meta-analysis. It was subject to the cumulative weaknesses of the included studies. This review included predominantly retrospective studies, most of which were non-comparative studies. Unfortunately, there is no sufficient body of evidence in the literature involving prospective studies and randomized controlled trials. These retrospective studies were included to amass sufficient data for comparison, as only 7 comparative studies of surgical treatment of RLDH were available in this review.

Additionally, there was a significant amount of heterogeneity between the included studies regarding surgeon technique. Standardization of patient age and reporting of patient activity level across all studies were lacking—factors that may influence the risk of RLDH. Also, there were inherent differences in the patient selection process preoperatively that were the result of surgeon preference for a specific surgical technique for different patient populations. This contributed to bias in the study design. Finally, the length of follow-up among the included studies was an additional source of variation, with reported complications and disk re-herniation rates subject to duration of patient follow-up in each study.

Despite these limitations, this study provides important aggregate data that can help drive decision-making regarding the type of surgical technique to address RLDH.

Conclusion

Decompression surgery and FS are viable surgical options to address RLDH. The complication risk profile of each procedure must be balanced with the risk of disk herniation recurrence and reoperation, as both procedures lead to improvements in JOA, ODI, and VAS back and leg scores postoperatively. Randomized trials assessing the clinical and functional outcomes of DS and FS, and possibly disk replacement, are needed to determine the optimal surgical technique to address RLDH.

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Level of Evidence Ratings and Quality Assessment Using the 12-Point Methodological Index for Non-randomized Studies Criteriaa

StudyLevel of EvidenceClearly Stated AimInclusion of Consecutive PatientsProspective Collection of DataEnd-points Appropriate for Study AimUnbiased Assessment of Study EndpointFollow-up Appropriate for Study AimLoss to Follow-up <5%Prospective Calculation of Study SizeAdequate Control GroupContemporary GroupsBaseline Equivalence of GroupsAdequate Statistical AnalysisMINORS Score
El Shazly et al12II22220220222018
Ruetten et al13II22221220222019
Sonmez et al14II22220220222018
Chen et al15III22020220222016
Lee et al16III22221220222019
Fu et al17III22120220222017
Hou et al18IV2212222N/AN/AN/AN/AN/A13
Ibrahim et al19IV2022022N/AN/AN/AN/AN/A10
Hoogland et al20IV2222120N/AN/AN/AN/AN/A11
Isaacs et al21IV2202022N/AN/AN/AN/AN/A10
Le et al7IV2202022N/AN/AN/AN/AN/A10
Li et al22IV2222222N/AN/AN/AN/AN/A14
Kim et al23IV2202222N/AN/AN/AN/AN/A12
Lequin et al24IV2202022N/AN/AN/AN/AN/A10
Niesche et al25IV2202022N/AN/AN/AN/AN/A10
Omidi-Kashani et al26IV2212022N/AN/AN/AN/AN/A11
Nomura et al27III22120220222017
Ahsan et al2III22020220222016
Eloqayli and Alomari28IV2222002N/AN/AN/AN/AN/A10
Kim et al29 (2)IV2202022N/AN/AN/AN/AN/A10
Shin et al30IV2002022N/AN/AN/AN/AN/A8
Smith et al31IV2202022N/AN/AN/AN/AN/A10
Chen et al32(2)IV2212222N/AN/AN/AN/AN/A13
Kim et al33 (3)IV2202022N/AN/AN/AN/AN/A10
Guo et al34IV2202022N/AN/AN/AN/AN/A10
Palma et al35IV2202022N/AN/AN/AN/AN/A10
Papadopoulos et al36III22020220222016
Dai et al37IV2202022N/AN/AN/AN/AN/A10
Niu et al38IV2202022N/AN/AN/AN/AN/A10
Ahn et al5IV2212222N/AN/AN/AN/AN/A13
Suk et al39IV2202022N/AN/AN/AN/AN/A10
Cinotti et al8III22022220222018
Herron40IV2202022N/AN/AN/AN/AN/A10
Silvers et al41IV2202022N/AN/AN/AN/AN/A10

Risk of Bias and Quality Assessment of the Comparative Studies

StudyAdequate RandomizationAllocation ConcealmentBlinding of PatientsBlinding of Care ProvidersBlinding of Outcome AssessorsBaseline ComparabilityDropout Rate DescribedFree of Selective Outcome ReportingCo-interventions Were SimilarAcceptable Compliance Between GroupsIntention-to-Treat AnalysisSimilar Outcome AssessmentTotal ScoreRisk of Biasa
El Shazly et al121000011111118Low
Ruetten et al131000011111118Low
Sonmez et al140000011111117Low
Chen et al150000011111117Low
Lee et al160000011111117Low
Fu et al170000011111117Low
Nomura et al270000011111117Low
Ahsan et al20000011111117Low
Papadopoulos et al360000011111117Low
Cinotti et al80000011111117Low

Risk of Bias and Quality Assessment of the Noncomparative Studies

StudyPatient Selection/Inclusion DescribedDrop-out Rate DescribedIndependent AssessorCointerventions DescribedTiming of Outcome Assessment SimilarTotal ScoreRisk of Biasa
Hou et al18110114Low
Ibrahim et al19110013Low
Hoogland et al20110013Low
Isaacs et al21110013Low
Le et al7110013Low
Li et al22111014Low
Kim et al23110013Low
Lequin et al24110013Low
Niesche et al25110013Low
Omidi-Kashani et al26110114Low
Eloqayli and Al-omari28110013Low
Kim et al29 (2)110013Low
Shin et al30110013Low
Smith et al31110013Low
Chen et al32 (2)110013Low
Kim et al33 (3)110013Low
Guo et al34110013Low
Palma et al35110013Low
Dai et al37110013Low
Niu et al38110013Low
Ahn et al5111013Low
Suk et al39110013Low
Herron40110013Low
Silvers et al41110013Low

Study Characteristics

StudyPublication YearStudy DesignTreatment MethodNo. of PatientsMean Age, yMean Follow-up, mo
El Shazly et al122013ProspectiveOD154138.6
PIF1540.536.3
PLF1542.736.1
Ruetten et al132009ProspectiveODN/A3924
EDN/A3924
Sonmez et al142012ProspectivePIF2046.5N/A
Chen et al152015RetrospectiveED1857.4N/A
OD2554.9N/A
Lee et al162009RetrospectiveED254234
OD2947.734.3
Fu et al172005RetrospectiveOD2341.185.6
PLF1842.292.6
Hou et al182015ProspectiveED255036
Ibrahim et al192015ProspectiveOD3445.127.1
Hoogland et al202008ProspectiveED26246.424
Isaacs et al212003ProspectiveED10N/A13.1
Le et al72003ProspectiveED10N/A18.5
Li et al222015RetrospectivePIF7346.249.2
Kim et al232014RetrospectiveED2653.119.3
Lequin et al242014RetrospectivePIF2645.715.3
Niesche et al252014RetrospectivePIF335750.2
Omidi-Kashani et al262014RetrospectivePIF5146.431.4
Nomura et al272013RetrospectiveED27N/AN/A
Ahsan et al22012RetrospectiveOD1839N/A
Eloqayli and Al-omari282012RetrospectiveED6454.5
Kim et al29 (2)2012RetrospectiveED1061.214.4
Shin et al302011RetrospectiveED4142.916
Smith et al312010RetrospectiveED16N/A14.7
Chen et al32 (2)2009RetrospectivePIF4354.245
Kim et al33 (3)2009RetrospectiveOD1444.6N/A
Guo et al342008RetrospectiveOD5142.2146.8
Palma et al352008RetrospectiveOD95N/AN/A
Papadopoulos et al362006RetrospectiveOD2739.2N/A
Dai et al372005RetrospectiveOD39N/A92
Niu et al382005RetrospectivePIF144425
Ahn et al52004RetrospectiveED4345.531
Suk et al392001RetrospectiveOD2842.1N/A
Cinotti et al81999RetrospectiveOD164424
Herron401994RetrospectiveOD50N/A54
Silvers et al411994RetrospectiveOD82N/A54

Effect Incidence of Clinical Outcomes Based on Type of Surgery

Type of SurgeryClinical Variables of InterestNo. of StudiesEffect Incidence95% Confidence IntervalQI2
Fusion surgeryDural tear95.3%−35.3% to 4.6%13.49740.73
Infection74.7%−31.1% to 40.6%18.98768.4
Neurological complication85.3%−35.4% to 45.9%17.57760.175
Re-recurrence30.0%−16.2% to 16.2%00
Reoperation412.1%−54.3% to 78.5%4.080926.4877
Decompression surgeryDural tear226.1%−35.6% to 47.8%106.768880.331344
Infection200.6%−16.4% to 17.6%187.6244489.8733877
Neurological complication91.9%−19.2% to 23.0%51.951384.6009
Re-recurrence165.2%−37.0% to 47.5%30.2101250.347767
Reoperation125.4%−34.5% to 44.8%65.247783.14117
Endoscopic diskectomyDural tear143.2%−27.3% to 34.0%60.895178.6518
Infection130.0%−13.7% to 13.4%00
Neurological complication40.0%−12.3% to 12.3%00
Re-recurrence125.3%−35.0% to 44.7%28.70561.6796
Reoperation62.5%−29.4% to 34.4%5.570510.2425
Open diskectomyDural tear810.8%−50.2% to 71.8%8.664619.2122
Infection71.7%−21.2% to 24.6%41.063010985.3883
Neurological complication53.4%−24.7% to 31.6%23.788383.185013
Re-recurrence55.2%−36.1% to 46.5%3.300980
Reoperation67.8%−39.6% to 55.1%2.64270
Posterolateral fusionDural tear28.9%−49.1% to 66.9%10
Infection22.8%−28.3% to 33.9%10
Neurological complicationN/AN/AN/AN/AN/A
Re-recurrenceN/AN/AN/AN/AN/A
ReoperationN/AN/AN/AN/AN/A
Posterior interbody fusionDural tear74.3%−31.3% to 39.8%13.1241154.28263
Infection55.5%−32.3% to 43.3%13.1692669.62624
Neurological complication76.0%−38.2% to 50.2%10.014165540.084873
Re-recurrence20.0%−16.3% to 16.3%00
Reoperation312.4%−54.3% to 79.2%2.01770220.87734

Meta-analysis of Changes Between Pre- and Postoperative Functional Outcome Scores Based on Type of Surgery

Type of SurgeryFunctional Outcome of InterestNo. of StudiesMean Difference Between Preoperative and Postoperative Scores95% Confidence IntervalPQI2
Fusion surgeryJOA414.2611.54 to 16.99<.0000116.5082%
ODI3−28.33−56.21 to −0.46.05000252.1299%
VASB4−5.32−6.69 to −3.94<.0000170.4096%
VASL4−6.34−8.07 to −4.62<.0000160.1095%
Decompression surgeryJOA312.9510.17 to 15.75<.000018.5477%
ODI5−38.46−56.93 to −19.99<.00010184.1598%
VASB6−3.88−6.24 to −1.52.00100134.1996%
VASL7−5.66−5.97 to −5.36<.000015.800%
Endoscopic diskectomyJOAN/A
ODI3−28.67−42.66 to −14.69<.0000128.9593%
VASB4−3.05−4.40 to −1.70<.0000110.6072%
VASL6−5.70−6.01 to −5.38<.000015.020%
Open diskectomyJOA312.9510.17 to 15.75<.000018.5477%
ODI2−53.12−67.86 to −38.39.006007.5387%
VASB2−4.76−9.47 to −0.06.0500030.6197%
VASLN/AN/AN/AN/AN/AN/A
Posterolateral fusionJOA214.078.49 to 19.66<.000019.4289%
ODIN/AN/AN/AN/AN/AN/A
VASBN/AN/AN/AN/AN/AN/A
VASLN/AN/AN/AN/AN/AN/A
Posterior interbody fusionJOA215.2613.87 to 16.65<.000016.3484%
ODI3−28.33−56.21 to −0.46.05000252.1299%
VASB4−5.32−6.69 to −3.94<.0000170.4096%
VASL4−6.34−8.07 to −4.62<.0000160.1095%
Authors

The authors are from the Department of Orthopaedic Surgery (RMA, AD, GMM, SP), UCLA Medical Center, Santa Monica, California; and Case Western Reserve University School of Medicine (AS), Cleveland, Ohio.

The authors have no relevant financial relationships to disclose.

Correspondence should be addressed to: Sina Pourtaheri, MD, Department of Orthopaedic Surgery, UCLA Medical Center, 1250 16th St, Ste 3145B, Santa Monica, CA 90404 ( spourtah@gmail.com).

Received: September 12, 2017
Accepted: September 26, 2017
Posted Online: June 26, 2018

10.3928/01477447-20180621-01

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