Yang et al. Journal of Orthopaedic Surgery and Research 2014, 9:10http://www.josr-online.com/content/9/1/10

RESEARCH ARTICLE Open Access

Clinical efficacy of posterior versus anteriorinstrumentation for the treatment of spinaltuberculosis in adults: a meta-analysisPinglin Yang, Xijing He*, Haopeng Li, Quanjin Zang and Baohui Yang

Abstract

Background: The aim of our study was to evaluate the clinical efficacy of posterior vs. anterior instrumentation forthe treatment of spinal tuberculosis in adults.

Methods: The electronic databases such as PubMed, MEDLINE, Springer, EMBASE, Google scholar, and Cochranelibrary were searched to select the potentially relevant reports that compared the efficacy of posteriorinstrumentation group (group A) with anterior instrumentation group (group B) in the treatment of spinaltuberculosis. Outcome assessments were correction of angle, loss of correction, fusion rate of the grafting bone,and complications after surgery.

Results: This meta-analysis included four trials published between 2006 and 2012, involving 291 adult patients(group A, 154; group B, 137) with spinal tuberculosis. The overall meta-analysis showed that there were nosignificant differences (P > 0.01) between group A and group B in correction of angle and loss of correction at finalfollow-up after operation The pooled WMD (weighted mean difference) of group A and group B was 2.85 (95% CI(confidence interval) = −1.25 ~ 6.94) and 1.14 (95% CI = −3.07 ~ 5.34), respectively. Besides, no significant differences(P > 0.01) were observed in fusion rate of the grafting bone and complications after operation between group Aand group B, and the pooled ORs (odds ratio) were 0.65 (95% CI = −0.23 ~ 1.85) and (95% CI = −0.19 ~ 1.50),respectively.

Conclusions: Our results suggested that the posterior instrumentation appeared to have the same clinical outcomewith the anterior instrumentation in the treatment of the adult patients with spinal tuberculosis.

Keywords: Adult spinal tuberculosis, Thoracic and lumbar, Meta-analysis

IntroductionTuberculosis (TB) is the most common granulomatousbacterial infection in the spine [1]. Spinal tuberculosis, alsocalled Pott's spine [2], is the most common form of extra-pulmonary tuberculosis [3]. It is generally accepted thatspinal TB is the most dangerous of any bone and joint TBbecause of its ability to cause bone destruction, deformity,and paraplegia [4]. There are conflicting guidelines andvariations in clinical practice in the management of spinaltuberculosis [5]. Various modalities of treatment rangingfrom only antitubercular drugs to radical procedures such

* Correspondence: xijing_h@vip.tom.comSecond Department of Orthopedics, Second Affiliated Hospital of Xi’anJiaotong University Medical School, No.157, West Fifth Road, Xi’an, Shaanxi710004, China

© 2014 Yang et al.; licensee BioMed Central LtCommons Attribution License (http://creativecreproduction in any medium, provided the orDedication waiver (http://creativecommons.orunless otherwise stated.

as anterior or combined approach surgeries have beensuggested to manage spinal tuberculosis [6]. Long periodsof immobilization, progressive kyphosis, and graft failureare the major postoperative problems encountered afteranterior radical surgical treatment for tuberculosis of thespine [7]. Posterior fusion and instrumentation can be aneffective solution for these problems [7]. Hibbs and Albeeintroduced posterior spinal fusion to stabilize the spineand promote healing [8,9].Whether the clinical efficacy of posterior instrumenta-

tion for the treatment of spinal tuberculosis in adults issuperior to anterior instrumentation still remains a contro-versy [3,10-12]. In order to achieve an integrative under-standing of the clinical response of patients to posteriorinstrumentation (group A) and anterior instrumentation

d. This is an Open Access article distributed under the terms of the Creativeommons.org/licenses/by/2.0), which permits unrestricted use, distribution, andiginal work is properly credited. The Creative Commons Public Domaing/publicdomain/zero/1.0/) applies to the data made available in this article,

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(group B), we conducted a systematic review of publishedfindings and used meta-analysis techniques to quantita-tively combine the clinic outcomes. Meta-analysis is astatistical procedure for combining the results of severalstudies to produce a pooled estimate of the major effectwith enhanced precision [13], and it is considered a power-ful tool for summarizing inconsistent results from differentstudies. We performed a meta-analysis to assess the cor-rection of angle, loss of correction with final follow-up,fusion rate of the grafting bone, and complications afteroperation in group A and group B.

Materials and methodsSource of materialsThe public databases including PubMed, MEDLINE andEMBASE, Springer, Elsevier Science Direct, CochraneLibrary, and Google scholar were searched for relevantreports published up to December 2012. The keywordsof ‘anterior,’ ‘posterior,’ ‘spinal tuberculosis,’ ‘thoracic andlumbar tuberculosis,’ ‘efficacy,’ ‘study,’ or ‘trial’ were usedfor searching. Meanwhile, references from retrieved pa-pers were checked for any additional studies. We onlyrecruited data from the fully published English paper,not from any meeting or conference abstract.

Inclusion and exclusion criteria of the studiesThe studies were included in this review if they met thefollowing criteria: (1) prospective studies, retrospectivestudies, or cross-sectional studies; (2) the subjects werepatients with spinal tuberculosis; (3) the studies comparedthe clinic outcomes of posterior instrumentation and an-terior instrumentation; and (4) the studies provided oddsratio (OR) or weighted mean difference (WMD).The studies were excluded if they met the following

criteria: (1) not published in English; (2) were reviews,letters, or comments; and (3) full texts were unavailable.

Evaluation of the quality and extraction of dataThe quality of study design, sample size, and recruitmentof respondents were evaluated. Initially, study titles andabstracts were read and then the full texts of potentialrelevant studies were screened to identify the finally eligibleones according to the inclusion criteria. Two investigatorsindependently completed this course. Disagreements be-tween the reviews were resolved by discussion until aconsensus was reached.We developed and modified a data extraction form after

a training exercise for investigators. Data items includedstudy details (e.g., the first author's name, year of studypublication, region of participants, design of studies, etc.),characteristics of participants (e.g., age, gender, and sam-ple size), and follow-up time with the patients. Two inves-tigators (HL and QZ) extracted the data independentlyusing the standard protocol, and the result was reviewed

by a third investigator (BY). We contacted the authors ofthe studies included to obtain further information for dataitems that needed clarification. Discrepancies were re-solved by discussion with our research team or contract-ing with the original investigators, who were all sent thedata extraction sheets with requests for correction. We re-corded the first author's name, year of publication, coun-try, sample size, age, gender, and follow-up time withpatients of group A and group B.

Statistical analysisThe OR or WMD and their 95% confidence interval (CI)were selected as the evaluation index in current study. Weassessed the within- and between-study variation or het-erogeneity by testing Cochran's Q-statistic [14]. This het-erogeneity test assessed the null hypothesis that all studieswere evaluating the same effect. We also quantified theeffect of heterogeneity using I2 = 100% × (Q − df)/Q [15],which measures the degree of inconsistency in the studiesby calculating the percentage of the total variation acrossstudies resulting from the heterogeneity rather than bychance. A significant Q-statistic (P < 0.10) or I2-statistic(I2 > 50) indicated heterogeneity across studies, and thenthe random effects model was used for meta-analysis.Otherwise, the fixed effects model was used. The fixed ef-fects model assumes that all of the studies are estimatingthe same underlying effect and considers only within-study variation.The overall estimate of ORs or WMD was obtained

using Mantel-Haenszel method in the fixed effects model[16] and using DerSimonian and Laid method in the ran-dom effects model [17]. Pooled ORs or WMD in themeta-analysis was performed by weighting individual ORsor mean differences by the inverse of their variance. Thesignificance of the pooled ORs or WMD was determinedby the Z-test. Analyses were performed using the softwareReview Manager 5.1 (Cochrane Collaboration, http://ims.cochrane.org/revman). A P value less than 0.05 was con-sidered statistically significant.

ResultsCharacteristics of eligible studiesInitially, a total of 865 papers potentially relevant to thesearch terms (PubMed, 232; MEDLINE, 89; Springer,208; Elsevier Science Direct, 161; Cochrane Library, 10;Google Scholar, 165) were identified and finally only foureligible articles were included in current study. The flowchart of the study selection is shown in Figure 1. Afterthe duplicates were removed, 238 potentially relevantstudies were retained, 195 of which were excluded basedon the screening of abstracts, since they were reviews (n =45) not related to spinal tuberculosis (n = 86) or did notreport posterior instrumentation (n = 64). The full texts ofthe left 43 studies were screened and 39 were excluded

Figure 1 Flow diagram for selection of studies and specificreasons for exclusion from the meta-analysis.

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(16 for just only reported posterior instrumentation databut not for comparison; 23 due to no available data).Finally, four studies [3,10-12] were included in the

meta-analysis as shown in Table 1. The eligible studieswere published between 2006 and 2012 including a totalof 291 spinal tuberculosis adults (group A, 154; group B,137) who underwent the treatment with anterior or pos-terior instrumentation. The age of the patients rangedfrom 33.6 to 63.7 years old. The smallest sample sizewas 17 and largest was 157. The follow-up time of theincluded studies was from 5 to 72 months.

Overall effects of correction of angle after operation ingroup A vs. group BThe summary of the meta-analysis for correction of angleafter operation is shown in Figure 2. The data of effect oncorrection of angle was available in three separate studies[3,10,12] consisting of 220 patients (group A, 117; groupB, 103). The random effects model was applied to deter-mine the correction of angle after operation between thetwo groups due to the evidence of heterogeneity (Q2 =37.08, I2 = 95.0%, P < 0.01). The pooled WMD is 2.85

Table 1 Characteristics of studies included in the meta-analys

Study Year ofpublication

Country Samplesize

Follow-up,mo Sam

size

Garg et al. [12] 2012 India 70 5 to 14 36

Lee et al. [11] 2006 Korea 17 6 to 42 10

Ma et al. [10] 2012 China 157 22 to 72 83

Pu et al. [3] 2012 China 47 12 to 62 25

group A posterior instrumentation group, group B anterior instrumentation group, N

(95% CI = −1.25 ~ 6.94, P > 0.05) for patients in group Acompared to group B, suggesting that there was no sig-nificant difference in the correction of angle after oper-ation between these two treatment groups at the end offollow-up times.

Overall effects of the loss of correction with finalfollow-up after operation in group A vs. group BThree separate studies [3,10,12] consisting of 220 patients(group A, 117; group B, 103) were included to assess theoverall effects of the loss of correction. Heterogeneity wasobserved among studies (Q2 = 28.18, I2 = 93.0%, P < 0.01),so random effects model was applied to pool the results.No statistical significance was found in the loss of correc-tion at final follow-up time between group A and group B(WMD= 1.14; 95% CI = −3.07 ~ 5.34, P > 0.05) (Figure 3).

Overall effects of fusion rate of the grafting bone afteroperation in group A vs. group BThe results for fusion rate of the grafting bone after oper-ation are summarized in Figure 4. Four separate studies[3,10-12] consisting of 290 patients (group A, 153; groupB, 137) were included in this meta-analysis. Testing ofheterogeneity was not significant (Q2 = 0.37, I2 = 0.0%,P > 0.01), so fixed effects model was valid to conduct themeta-analysis. The overall meta-analysis showed that thepooled ORs were 0.65 (95% CI = −0.23 ~ 1.85, P > 0.05) forpatients in group A compared to group B, indicating thatthere were no significant differences in fusion rate of thegrafting bone after operation between posterior instru-mentation and anterior instrumentation for the treatmentof spinal tuberculosis.

Overall effects of complications after operation in groupA vs. group BFour separate studies [3,10-12], consisting of 291 pa-tients (group A, 154; group B, 137), were included inthis meta-analysis. Because of homogeneity among theliteratures (Q2 = 1.84, I2 = 0.0%, P > 0.01), the fixed ef-fects model was used and postoperative complicationswere not found to be significantly different betweengroup A and group B (ORs = 0.54, 95% CI = −0.19 ~1.50, P > 0.05). The result suggested that posterior

is

Group A Group B

ple Age in years(mean ± SD)

Male (%) Samplesize

Age in years(mean)

Male (%)

33.6 NA 34 34.9 NA

63.70 ± 5.43 4 (40) 7 49 ± 15.87 1 (14)

39.8 ± 1.3 32 (39) 74 38.3 ± 1.3 33 (45)

38.1 10 (40) 22 37.8 7 (32)

A not applicable.

Figure 2 Forest plot of correction of angle in group A vs. group B.

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instrumentation may be comparable to anterior instru-mentation for the treatment of spinal tuberculosis incomplications after operation (see Figure 5).

DiscussionNowadays, many studies [3,10-12] have reported clinicalefficacy of posterior instrumentation group vs. anteriorinstrumentation group for the treatment of spinal tuber-culosis in adults. But these studies have shown contradict-ory results due to small sample sizes or low statisticalpower. In our meta-analysis, we combined four studiesthat compared the clinical outcomes of posterior withanterior instrumentation in treatment for 291 adultpatients with spinal tuberculosis. The results of this meta-analysis indicated that there were no significant differ-ences (P > 0.01) in the correction of angle and loss ofcorrection at the final follow-up time after operationbetween group A and group B. Besides, no significant dif-ferences (P > 0.01) were found in the fusion rate of thegrafting bone and complications after operation betweenthe two groups. These results demonstrated that posteriorinstrumentation may be equal to anterior instrumentationfor the treatment of spinal tuberculosis after operation inadults.The aims of treating spinal TB are to eradicate the in-

fection, prevent or treat neurological deficits, correct ky-phosis deformities, and finally to achieve normal sagittalcontours of the spinal column, unrestricted motility, andfull activities of daily living as soon as possible [1,4]. A

Figure 3 Forest plot of loss of correction with final follow-up in group

variety of approaches are used in the surgical treatmentof spinal tuberculosis, such as anterior instrumentation,posterior instrumentation, and anterior combined withposterior instrumentation. The majority of researchersfavor the anterior approach due to the direct accessionto the lesion, optimal visualization, and the direct andcomplete decompression of spinal cord provided by an-terior radical surgical excision. However, the stability ofanterior instrumentation appears to be a considerableissue. With the development in treating spinal tubercu-losis, posterior approach has been proposed and becomepopular. A posterior approach in combination with in-ternal fixation and posterior or posterolateral fusion(with or without placement of posterior interbody grafts)may be sufficient for the debridement of the infection andto allow spinal stabilization in patients with spinal tuber-culous spondylitis [18]. An advantage of one-stage poster-ior circumferential fusion is avoiding thoracotomy andthoracoabdominal approaches, which exert considerablestress on the lungs especially so in the elderly who oftensuffers from impaired pulmonary function [19-21]. Todate, controversy was remaining on whether anterior orposterior instrumentation should be applied in the treat-ment of spinal tuberculosis. In the report of Jin et al. [4],one-stage anterior interbody autografting and instrumen-tation were applied to treat thoracolumbar spinal tubercu-losis in adults and a mean of 18° of kyphosis correctionwas achieved during the follow-up period. Zhao et al. [22]found that kyphotic deformity was corrected by an

A vs. group B.

Figure 4 Forest plot of fusion rate of the grafting bone in group A vs. group B.

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average of about 16° using anterior instrumentation andfusion, and in the follow-up period, correction loss was 1°(6.3%). Moon et al. [23] and Chen et al. [24], respectively,reported 44 and 29 patients with spinal TB who weretreated by anterior radical surgery combined with poster-ior instrumentation and fusion. The average correctionangle was about 18° and the loss of correction after sur-gery was negligible (1°–3°). It appears that anterior andposterior instrumentation can achieve similar and goodresults in correcting the deformity and maintaining thatcorrection, which were in accordance with our results.However, many researchers believe that the anterior ap-proach easily results in nerve and vascular injuries, in-creasing surgical complications [25,26]. In the currentstudy, we reviewed four reports and concluded that therewas no significant difference in the surgery-related com-plications between posterior instrumentation group andanterior instrumentation group. Therefore, further studiesare needed to evaluate the complications resulted by pos-terior instrumentation and anterior instrumentation.Some limitations of this study should be discussed.

First of all, only published studies were included in thepresent meta-analysis. Thus, publication bias may haveoccurred and funnel plot asymmetry analysis is required.

Figure 5 Forest plot of complication in group A vs. group B.

Secondly, significant heterogeneities among studies weredetected in the current meta-analysis that may distortthe pooled results. The degree of heterogeneity is one ofthe major concerns in meta-analysis for the validity ofmeta-analysis [27], as non-homogeneous data are liablefor the misleading results. Meanwhile, different popula-tions may lead to the heterogeneity of these trials. Weshould interpret these results with caution because thepopulation from each country was not uniform. Finally,the recruited studies were not randomized controlledtrial (RCT), and the numbers of studies were small (onlyfour), so there were still need more and high-qualityRCTs to test and verify the results of this meta-analysis.Therefore, we minimized the likelihood of bias by devel-oping a detailed protocol before initiating the study, byperforming a meticulous search for published studies,and using explicit methods for study selection, data ex-traction, and data analysis.

ConclusionsOur results suggested that posterior instrumentationmay have the same clinical outcome compared with an-terior instrumentation in the treatment of spinal tuber-culosis in adults.

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AbbreviationsOR: odds ratio; RCT: randomized controlled trial; TB: tuberculosis;WMD: weighted mean difference.

Competing interestsThe authors declare that they have no competing interests.

Authors’ contributionsPY and BY participated in the design of this study, and they both performedthe statistical analysis. HL carried out the study, together with QZ, andcollected important background information; XH drafted the manuscript. Allauthors read and approved the final manuscript.

AcknowledgementsWe wish to express our warm thanks to all the authors who havecontributed to the study.

Received: 28 September 2013 Accepted: 6 January 2014Published: 21 February 2014

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doi:10.1186/1749-799X-9-10Cite this article as: Yang et al.: Clinical efficacy of posterior versusanterior instrumentation for the treatment of spinal tuberculosis inadults: a meta-analysis. Journal of Orthopaedic Surgery and Research2014 9:10.

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