Minimally invasive versus open transforaminal lumbar interbody fusionfor lumbar degenerative diseasein Chinese populations: new data and meta-analysis.

Abstract

Purpose

This is a meta-analysis of randomized and non-randomized studies comparing the clinical and radiological efficacy of minimally invasive (MI) and conventional open transforaminal lumbar interbody fusion (open-TLIF) for degenerative lumbar diseases.We performed this meta-analysis to investigate currentMinimally invasive versus open transforaminal lumbar interbody fusionfor lumbar degenerative diseasein mainland China.

Methods

PubMed, Embase, Chinese Biological Medical Literature database (CBM), Chinese National Knowledge Infrastructure database (CNKI), and the Chinese Wanfang and Chongqing VIP database were searched for associated studies.13studies that met our inclusion criteria. A total of 1214patients were examined. Pooled estimates of clinical and radiological outcomes, and corresponding 95 % con-fidence intervals were calculated.

Results

The pooled data revealed thatMI-TLIFcan reduce Intraoperative blood loss、Postoperative blood loss、Hospital stay (days)、Total blood transfusion (ml) and Incision length (cm) compared withOpen-TLIFfor treating degenerative lumbar diseases. However, MI-TLIF significantly increased the intraoperative X-ray exposure. Both techniques had similar operative timeand complication .

Conclusions

Based on the available evidence, MI-TLIF for degenerative lumbar diseases might lead to better patient-based outcomes. MI-TLIF would be a promising procedure. More randomized con-trolled trials are needed to compare these two surgical options.

Keywords:Transforaminal lumbar interbody fusion ,Minimally invasive,Pedicle screw fixation,Meta-analysis

Introduction

Degenerative disc disease is one of the most common causes of low back pain worldwide. Among a variety of approaches [1, 2], open transforaminal lumbar interbody fusion (open-TLIF) is one of the treatments of choice for a variety of degenerative lumbar disorders[3]. Transforaminal lumbar interbody fusion (TLIF), first described in 1982 by Harms and Rolinger, is an alternative to PLIF that implements a unilateral approach to the disc space and minimizes retraction of the neural elements7. Similar to PLIF, TLIF provides good fusion rates, maintains the intervertebral space and foraminal dimension, and restores vertebral alignment [4–5]. Although clinical studies have proved the efficacy of conventional open-TLIF, there are concerns regarding lengthy hospital stays, excessive blood loss, and postop-erative complications. These concerns are often associated with the stripping of paravertebral muscles [6, 7]. To address these problems, Foley et al. [8] described an alternative technique: minimally invasive TLIF (MI-TLIF).

MI-TLIF was developed with the advancement of modern surgical instrumentation and optical systems [6].

minimally invasive surgery (MIS) techniques for TLIF (MIS-TLIF) have been introduced with the goals of smaller operative wounds, reduced trauma to paraspinal muscles, and quicker postoperative recovery, all of which may in turn result in minimized estimated blood loss, decreased hospital length of stay (LOS), and decreased rates of surgical site infectionin contrast to the protracted hospital stays and significant costs associated with open-TLIF procedures[9-13].Through a tubular retraction system, MI-TLIF might reduce muscular dissection. However, several disadvantages have also been reported. First, with limited visibility and working space, MI-TLIF requires good familiarity of anatomy. Some sur-geons have suggested that MI-TLIF could increase surgicaltime [14-15,29, 33]. Secondly, to facilitate a minimally invasive approach, more X-ray exposure was used [16]. Thirdly, MI-TLIF has a steep learning curve and is a technically demanding procedure. High complication rates have been reported during the learning stage [17 ].

In the recent years, an increasing number of studies have been conducted to compare the effectiveness between MI-TLIF and open-TLIF for degenerative lumbar diseasesin mainland China. However, only limited Class I evidence is available [18]. Meta-analysis is a statistical method used within a systematic review, which can integrate the results of different independent studies addressing the same question into a quantitative summary [19, 20], increase the statistical power and precision of estimates for defined endpoints, and draw robust conclusions from conflicting reports. Therefore, meta-analyses and systematic reviews are often advocated as the best source of evidence to guide both clinical decision and healthcare policy [21, 22].

To date, there has been no systematic review or meta-analysis to compare the effectiveness between MI-TLIF and open-TLIF for degenerative lumbar diseasesin mainland China. The objective of the present study was to provide cumulative effect estimates of the clinical and radiological outcomes using meta-analysis and to determine which surgical technique was more beneficial.

Materials and methods

Search strategy and inclusion criteria

Because only a small number of randomized controlled trials is available in the literature, non-randomized comparative studies (prospective and retrospective) were also included. A literature search was conducted up to October 2015usingPubMed, Embase, Chinese Biological Medical Literature database (CBM), Chinese National Knowledge Infrastructure database (CNKI), and the Chinese Wanfang and Chongqing VIP database . We screened all fields by combining the term ‘‘transforaminal lumbar interbody fusion’’ or ‘‘TLIF’’ with ‘‘MIS’’, ‘‘minimally invasive’’, or ‘‘minimally invasive spine surgery’’.

The following eligibility criteria were applied: (1) the study included a comparative design (MI-TLIF versus open-TLIF). (2) The study population consisted of adult patients suffering from degenerative lumbar diseases (disc herniation, spinal stenosis, or spondylolisthesis). Isthmic spondylolisthesis was not excluded. (3) At least one of the following outcomes should be reported: perioperative results (operative time, blood loss, or hospital stay), X-ray exposure time, pain or disability improvement, complications, or re-operations. (4) A minimum sample size of ten was required for both groups. Articles were excluded if they had any of following characteristics. (1) Patients suffering from spinal deformities, trauma, or spinal tumors. (2) Postoperative medicine use, such as steroids or chemotherapy agents, which might affect the fusion rate. (3) Biomechanical study, cadaveric study, comment, and case report. (4) Repeated studies. Two reviewers of this paper independently extracted data using a standardized form. Inconsistencies between reviewers’ data were resolved through discussion until a consensus was reached.

Data extraction

We extracted data based on the following categories. (1) Study year, country, and study design. (2) Basic studycharacteristics including patients’ inclusion/exclusion cri-teria, enrolled number, age, and sex proportion. (3) Base-line comparison information of confounding factors, such as sex, age, height, weight, BMI, diagnosis, surgical level, insurance, education, smoking status, alcohol use, workers’ compensation, and concomitant diseases. (4) Surgical information, including detailed spinal level and level numbers, instrumentation, and bone graft. (5) Perioperative outcomes such as operative time, intraoperative and post-operative blood loss, intraoperative X-ray exposure time, and hospital stay. (6) Functional outcome improvement at last follow up including visual analogue scores (VAS), Oswestry disability index (ODI), and Japanese Orthopedic Association scores (JOA). (7) Fusion assessment method, fusion success criteria, and fusion rate at last follow-up. (8) Complication types and complication rates. Both total and specified compli-cation rates were extracted. We referred to the previous published reviews to categorized specified complication types [23].

Study quality

Because both randomized and non-randomized studies were included in current analysis, we applied two assessing tools. For non-randomized studies, the validated instrument called MINORS score was used[24]. A maximum score of 24 points can be generated for each included comparative study. For prospective randomized controlled trials, the Detsky quality index was applied [25].The total score is 20 for positive trials and 21 for negative trials. Based on the previous published papers, studies scoring [75 % of the maximum MINORS or Detsky score were designated high quality. Each eligible study was independently reviewed by two raters for methodological quality (HL Zhang ,XL Zhou and M Xu ). All discrepancies were resolved by consensus.

Meta-analysis

We performed data synthesis and analysis with the Review Manager software provided by Cochrane Collaboration (RevMan Version 5.1; The Nordic Cochrane Center, The Cochrane Collaboration, Copenhagen, Denmark). The assessment for statistics heterogeneity was calculated through Chi2andI2test. When the Chi2wasP> 0.05 orI2< 20% indicating low statistical heterogeneity, a fixed effect model was used. A random effect model was used when Chi2wasP< 0.05 andI2> 20%. For continuous data, means and standard deviations were pooled to a weighted mean difference (WMD) and 95% confidence interval (CI) in the meta-analysis. For binary data, odds ratio (OR) and 95% confidence interval (CI) were assessed (α= 0.05 for the inspection standards) [26]. Publication bias was assessed by using a funnel plot of the most frequently reported outcome.

Results

The search strategy (Fig. 1) identified Thirteencomparative studies that met the inclusion criteria, including one ran-domized controlled trial, fiveprospective comparative studies, and sevenretrospective comparative studies. According to the criteria outlined in the Methods section, 1403 related articles were identified from all of the databases (Fig. 1).Finally, 13 studies were included in our study [27-39]. No additional articles can be obtained from the reference lists.We only included the single level group because the patient’s num-ber of multilevel fusion procedures was not large enough to meet our inclusion criteria. The search of the references in the retrieved articles did not yield any other eligible studies.

Fig. 1 Selection of relevant publications, reasons for exclusion

Table 1 Characteristics of included studies

RCSretrospective comparative study,PCSprospective comparative study,RCTrandomized controlled trial,NAnot available

Study characteristics

According to the quality assessment criteria, there were six high quality and seven low quality studies. The patients’ diagnoses included degenerative lumbar disease in thirteen studies.Five of the twelve studies also enrolled patients with isthmic spondylolisthesis. One study was focused on revi-sion surgery. twelve studies involved only single level pro-cedures.

Baseline comparisons were performed in the twelveincluded studies. However, the comparisons varied in these papers. Onearticles analyzed four factors, four articles analyzed sevenfactors, two articles analyzed eight factors, four articles analyzed nine factors, onearticles analyzed tenfactors, and onearticles analyzed elevenfactors, One paper compared seven factors between the open and MI groups. The reported baseline characteristics were statisti-cally similar between the two groups in all studies (Table 2).The most frequently reported clinical outcomes were mean back ,leg pain VAS improvement ,japanese Orthopaedic Association (JOA) and mean ODI improvement. Although the mean score improvement could be extracted from the majority of these studies, none provided the corresponding SD. As a result, we used a descriptive method for these indexes.

Table 2 Comparison of baseline characteristics

aRCT was assessed using Detsky score and non-RCT was assessed using MINORS score

Operative time

(Fig. 2 Forest plot illustrating operative timeof meta-analysis comparing MI-TLIF with open-TLIF)

All Thirteenstudies [27-39 ] provided data of operation time and were eligible in the form of mean and standard deviation (SD). There were 1214degenerative lumbar diseases included, 589 patients with the minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and 625 with theconventional open transforaminal lumbar interbody fusion (Open-TLIF) . The heterogeneity test indicated a statistical evidence of heterogeneity (Chi2= 273.36,P< 0.00001,I2= 96%). We pooled data by a random effect model which indicated that there was no statistical difference in operation time between the two groups. (Mean difference: 18.80, 95% CI: 0.07~37.53,P= 0.05) (Fig. 2).

Intraoperative blood loss

All Thirteenstudies [27-39] provided data of intraoperative blood lossand were eligible in the form of mean and standard deviation (SD). There were 1214 degenerative lumbar diseases included, 589 patients with the MI-TLIFand 625 with theOpen-TLIF. The heterogeneity test indicated a statistical evidence of heterogeneity (Chi2= 290.66,P< 0.00001,I2= 96%). and data pooled by a random effect model indicated that Intraoperative blood losssignificantly favored the Open-TLIF.(Mean difference: −258.13, 95% CI: −319.78~−196.13,P< 0.00001) (Fig. 3).

Fig. 3 Forest plot illustrating Intraoperative blood lossof meta-analysis comparing MI-TLIF with open-TLIF

Postoperative blood loss

There were eight articles [27-31,35,38-39] involving855degenerative lumbar diseaseswhich provided data of postoperative blood loss. The heterogeneity test indicated that there was a statistical heterogeneity (Chi2 = 146.45, P < 0.00001, I2= 95%), and data pooled by a random effect model indicated that Postoperative blood losssignificantly favored the Open-TLIF.(Mean difference: −117.16, 95% CI: −155.07~−79.24,P< 0.00001< 0.05) (Figure 4).

Figure 4 Comparison of postoperative blood lossbetween MI-TLIFand Open-TLIF.

X-ray exposure time(s)

There were five articles [28,32,34,37,39] involving657 patientswhich provided data ofX-ray exposure time. The heterogeneity test indicated that there was a statistical heterogeneity (Chi2 = 87.00, P < 0.00001, I2= 95%), There was obvious evidence for statistically significant heterogeneity(Mean difference: 26.80, 95% CI: 15.77~37.84,P< 0.00001) (Figure 5).

Fig. 5 Forest plot illustratingX-ray exposure of meta-analysis comparing MI-TLIF with open-TLIF

Hospital stay (days)

Sixstudies [28.29,31,33,36,37] included data of hospital stay. There were 447 degenerative lumbar diseases included226 patients with the MI-TLIFand 221with theOpen-TLIF. The heterogeneity test indicated no statistical heterogeneity (Chi2= 8.37,P= 0.14,I2=40%). Over-all, the weighted mean difference was 3.11days shorter in the MI-TLIF group (95 % CI −3.64~−2.58,P< 0.00001) than that in the open TLIFgroup. (Figure 6).

Figure 6 Comparison of Hospital staybetween MI-TLIFand Open-TLIF.

Preoperative back pain VAS

There were eleven articles [28-32,34-39] involving1071patientswhich provided data ofPreoperative back pain VAS. The heterogeneity test indicated a statistical evidence of heterogeneity (Chi2= 6.42,P= 0.78,I2= 0%). We pooled data by a fixedeffect model which indicated that there was no statistical difference in Preoperative back pain VASbetween the two groups. (Mean difference: 0.13, 95% CI: −0.09~0.36,P= 0.25) (Fig. 7).

Figure 7 Comparison of Preoperative back pain VASbetween MI-TLIFand Open-TLIF.

Latest back pain VAS

There were twelvearticles [27-32,34-39] involving1156patientswhich provided data ofPreoperative back pain VAS. The heterogeneity test indicated a statistical evidence of heterogeneity (Chi2= 160.71,P< 0.00001,I2= 94%). We pooled data by a randomeffect model which indicated that there wasSignificant heterogeneity was detected among the studies. (Mean difference: −0.52, 95% CI: −0.77~−0.26,P< 0.0001) (Fig. 8).

Figure 8 Comparison of Latest back pain VASbetween MI-TLIFand Open-TLIF.

Preoperative leg pain VAS

There were three articles [35,36,38] involving214patientswhich provided data ofPreoperative back pain VAS. The heterogeneity test indicated a statistical evidence of heterogeneity (Chi2= 2.62,P= 0.27,I2= 24%). We pooled data by a fixedeffect model which indicated that there was no statistical difference in Preoperative leg pain VAS between the two groups. (Mean difference: −0.20, 95% CI: −0.64~0.25,P= 0.39) (Fig. 9).

Figure 9 Comparison ofPreoperative leg pain VAS between MI-TLIFand Open-TLIF.

Latest leg pain VAS

Four articles [30,35,36,38 ] involving266patientswhich provided data ofLatest leg pain VAS. The heterogeneity test indicated a statistical evidence of heterogeneity (Chi2= 4.71,P=0.19,I2= 36%). We pooled data by a fixedeffect model which indicated that there wasSignificant heterogeneity was detected among the studies. (Mean difference: −0.41, 95% CI: −0.47~−0.34,P< 0.00001) (Fig. 10).

Figure 10 Comparison of Latest leg pain VASbetween MI-TLIFand Open-TLIF.

Preoperative ODI

There were ten articles [28-32,34-39] involving985patientswhich provided data ofPreoperative ODI. The heterogeneity test indicated a statistical evidence of heterogeneity (Chi2= 61.15,P< 0.00001,I2= 85%). We pooled data by a randomeffect model which indicated that there was no statistical difference in Preoperative ODI between the two groups. (Mean difference: −0.40, 95% CI: −2.70~1.89,P= 0.73) (Fig. 11).

Figure 11 Comparison of Preoperative ODIbetween MI-TLIFand Open-TLIF.

Latest ODI

Ten articles [28-32,34-39 ] involving266patientswhich provided data ofLatest ODI. The heterogeneity test indicated a statistical evidence of heterogeneity (Chi2= 133.28,P< 0.00001,I2= 93%). We pooled data by arandomeffect model which indicated that there wasSignificant heterogeneity was detected among the studies. (Mean difference: −2.36, 95% CI: −4.39~−0.34,P= 0.02) (Fig. 12).

Figure 12 Comparison of Latest ODI between MI-TLIFand Open-TLIF.

Preoperative JOA

There were three articles [27,36,38] involving191 patientswhich provided data ofPreoperative JOA.The heterogeneity test indicated a statistical evidence of heterogeneity (Chi2= 0.60,P= 0.74,I2= 0%). We pooled data by a fixedeffect model which indicated that there was no statistical difference in Preoperative JOA between the two groups. (Mean difference: −0.20, 95% CI: −1.03~0.64,P= 0.65) (Fig. 13).

Figure 13 Comparison of Preoperative JOA between MI-TLIFand Open-TLIF.

Latest JOA

There were three articles [27,36,38 ] involving266patientswhich provided data ofLatest ODI. The heterogeneity test indicated a statistical evidence of heterogeneity (Chi2= 9.56,P-0.008,I2= 79%). We pooled data by arandomeffect model which indicated that there wasno Significant heterogeneity was detected among the studies. (Mean difference: 2.36, 95% CI: −0.92~5.65,P= 0.16) (Fig. 14).

Figure 14 Comparison of Latest JOAbetween MI-TLIFand Open-TLIF.

Total blood transfusion (ml)

There were two articles [27,29] included with 126 patients providing data for blood transfusion. There wasSignificant heterogeneity was detected among the studies. (Mean difference: −124.00, 95% CI: −169.04~−78.96,P< 0.00001) (Fig. 15).

Figure 15 Comparison of Total blood transfusionbetween MI-TLIFand Open-TLIF.

Incision length (cm)

Two articles [35,36 ] involving166patientswhich provided data ofIncision length

. The heterogeneity test indicated a statistical evidence of heterogeneity (Chi2= 2.54,P=0.11,I2= 61%). We pooled data by afixedeffect model which indicated that there wasSignificant heterogeneity was detected among the studies. (Mean difference: −6.53, 95% CI: −7.04~−6.01,P< 0.00001) (Fig. 16).

Figure 16 Comparison ofIncision length between MI-TLIFand Open-TLIF.

Complications

There were no statistically significant differences between the MIand open groups for complications such asScrew malposition,Cage migration,CSF leak,Superficial wound infection,Deep wound infection,Neurologic deficit,Pulmonary embolus,Ileus,Nonunion,and Revision surgery.(Mean difference: 0.76, 95% CI: 0.38~1.54,P=0.45) (Fig. 17).

Fig. 17 Forest plot illustrating specified complication rate of meta-analysis comparing MI-TLIF with open-TLIF

Publication bias

Fig. 18 Funnel plot of total complication rate

The assessment of publication bias complication rate indicated a mild asymmetry. The funnel plot of operation time and the rate of reoperation demonstrated limited evidence of small study exclusion and publication bias with an asymmetrical diagram with few studies plotted on the liftside of the funnel.

Discussion

Degenerative spinal disease has become a greater problem than before. Its spectrum includes degenerative disc diseases, facet joint arthritis, spinal stenosis, degenerative spinal scoliosis and spondylolisthesis.1 Often, they present with back pain, radicular pain and stiffness resulting in numerous people unable to perform in their work and losing quality of life.Transforaminal lumbar interbody fusion (TLIF) has become a popular and well-established technique after being introduced by Harms and Rolinger in 1982 [40]. Minimally invasive surgery has gained in popularity in modern orthopaedic trauma because it has been shown to be associated with reduced operation time, decreased bleeding and postoperative pain, reduced postoperative morbidity, and faster recovery of function [41–43].The advantages associated with MI-TLIF might be attributed to less intra-operative dissection and retraction of paravertebral muscles [44-45]. Shunwu et al. [29] found the minimally invasive group was associated with a significantly lower creatine kinase (a marker of muscle injury) level on the third postoperative day. Wang et al. [30] observed no differences in postoperative serum creatine kinase levels between the MI and open groups.

The purpose of this meta-analysis and systematic review was to summarize the existing high levels of evidence to determine the safety and efficacy of the minimally invasive TLIF compared with Open-TLIF.This study demonstrated thatMI-TLIFcan reduce Intraoperative blood loss、Postoperative blood loss、Hospital stay (days)、Latest back pain VAS、Latest leg pain VAS、Latest ODI、Latest JOA、Total blood transfusion (ml) and Incision length (cm) compared withOpen-TLIFfor treating degenerative lumbar diseases. However, no significant differences were observed between the two groups in terms ofOperative time 、Preoperative back pain VAS、Preoperative leg pain VAS、Preoperative ODI、Preoperative JOA and Complications.

MI-TLIF significantly increased the X-ray exposure time[46]. Various factors may have contributed to the prolonged X-ray exposure time of our MI-TLIF approach. First, surgeons are required to operate through limited exposure and are forced to maneuver in less space through the tubular dilator retractors. Second, better coordination between the surgeon and assistant is necessary to maintain a bloodless field during surgery. Last, as with all minimally invasive surgical strategies, this technique is associated with a steep learning curve. in this meta-analysis significantly MI-TLIF is a promising proce-dure, but more effort should be conducted to reduce Operative time and Complications in the future.

Our meta-analysis revealed that there was no significant difference between the MI and open-TLIF with regard to operative time. However, several studies have reported a trend of longer operative time for the MI-TLIF group [27-29, 31-35,37-38]. One reason might be that MI-TLIF, which was performed in limited space, is a more technically demanding procedure. A learning curve exists in the early stage of performing this surgery [28, 33, 37].

For complication , all studies showed statistically insignificant difference. The reoperation rate for both MI and open techniques were very low . Reasons for reoperation were similar among the studies, including pedicle screw or inter-vertebral graft malposition/loosing/migration, pseudarthrosis, and epidu-ral hematoma. However, we found the definition of com-plication was different in each study. Thus, pooling of the complication data might lead to bias. The main complica-tion types included graft malposition, cage migration, non-union, dural tear, and infection. It should be noted that for a specific complication type, pooled results revealed no significant difference between MI and open method.With such MI-TLIF complications seen in various studies, including ours, the selection of MI-TLIF candidates should be very stringent. Prevention and early detection of complications are essential to avoid poor outcomes.

Our study has a number of weaknesses. First of all, both prospective and retrospective comparative studies were selected for analysis. Methodology defects have been found in some of these studies, including failure to collect data prospectively, non-consecutive enrollment of patients, inadequate baseline comparisons, and improper blinding or non-blinding evaluation. Thus, the level of evidence for this meta-analysis was not high. Secondly, statistical het-erogeneity was detected among the studies particularly when we pooled the continuous outcomes. The heteroge-neity might be explained by the study design, study quality, patients’ characteristics, and the diverse technical specifi-cations. Thirdly, multiple assessment tools and fusion cri-teria, used in the included studies might confounded the combined results. Lastly, incomplete data recording was observed when we extracted clinical outcomes. Pooling of such data might lead to bias. Despite these weaknesses, our meta-analysis can still provide some value for clinical reference due to the lack of high quality randomized con-trolled trials. In summary, this meta-analysis demonstrated that

In this meta-analysis significantlyMI-TLIF is a promising proce-dure, but more effort should be conducted to reduce Operative time and Complicationsin the future. Because patients selected for MI-TLIF or open-TLIF may have difference in symptoms and severity of diseases, high-quality randomized controlled trials are also needed to further compare these two techniques.Future well-designed RCTs are needed to determine whether MI-TLIF is associated with reduced operation time and better functional recovery compared with Open-TLIF.

Statement of Funding

This study is self-financing research.

References

1.Irwin ZN, Hilibrand A, Gustavel M, et al. Variation in surgical decision making for degenerative spinal disorders. Part I: lumbar spine.Spine (Phila Pa 1976)2005;30(19):2208–13.

2.Roh JS, Teng AL, Yoo JU, et al. Degenerative disorders of the lumbar and cervical spine.Orthop Clin North Am.2005;36(3):255–62.

3.Lauber S, Schulte TL, Liljenqvist U, et al. Clinical and radiologic 2–4-year results of transforaminal lumbar interbody fusion in degenerative and isthmic spondylolisthesis grades 1 and 2.Spine (Phila Pa 1976)2006;31(15):1693–8. 4.Pumberger M, Hughes AP, Huang RR, et al.Neurologic deficit following lateral lumbar interbody fusion.Eur Spine J.2012;21(6):1192–9.

5.Yson SC, Santos ER, Sembrano JN, et al.Jr Segmental lumbar sagittal correction after bilateral transforaminal lumbar interbody fusion.J Neurosurg Spine.2012;17(1):37–42.

6.Karikari IO, Isaacs RE .Minimally invasive transforaminal lumbar interbody fusion: a review of techniques and outcomes. Spine 2010,35:294–301

7.Wu RH, Fraser JF, Hartl R .Minimal access versus open transforaminal lumbar interbody fusion: meta-analysis of fusion rates. Spine.2010,35:2273–2281

8.Foley KT, Holly LT, Schwender JD.Minimally invasive lumbar fusion. Spine 2003,28:26–35

9.McGirt MJ, Parker SL, Lerner J, et al. Comparative analysis of perioperative surgical site infection after minimally invasive versus open posterior/transforaminal lumbar interbody fusion: analysis of hospital billing and discharge data from 5170 patients.J Neurosurg Spine.2011 Jun;14(6):771–778.

10.Parker SL, Adogwa O, Witham TF, et al. Post-operative infection after minimally invasive versus open transforaminal lumbar interbody fusion (TLIF): literature review and cost analysis.Minim Invasive Neurosurg.2011 Feb;54(1):33–37.

11.Schizas C, Tzinieris N, Tsiridis E, et al. Minimally invasive versus open transforaminal lumbar interbody fusion: evaluating initial experience.Int Orthop.2009 Dec;33(6):1683–1688.

12.Park Y, Ha JW. Comparison of one-level posterior lumbar interbody fusion performed with a minimally invasive approach or a traditional open approach.Spine (Phila Pa 1976)2007 Mar 1;32(5):537–543.

13.Thomsen K, Christensen FB, Eiskjaer SP, et al. Volvo Award winner in clinical studies. The effect of pedicle screw instrumentation on functional outcome and fusion rates in posterolateral lumbar spinal fusion: a prospective, randomized clinical study.Spine (Phila Pa 1976)1997 ,22(24):2813–2822.

14.Dhall SS, Wang MY, Mummaneni PV. Clinical and radiographic comparison of mini-open transforaminal lumbar interbody fusion with open transforaminal lumbar interbody fusion in 42 patients with long-term follow-up.J Neurosurg Spine.2008;9:560–565.

15..Schizas C, Tzinieris N, Tsiridis E, et al. Minimally invasive versus open transforaminal lumbar interbody fusion: evaluating initial experience.Int Orthop.2009;33:1683–1688.

16 Lee KH, Yue WM, Yeo W, Soeharno H, Tan SB (2012) Clinical and radiological outcomes of open versus minimally invasive transforaminal lumbar interbody fusion. Eur Spine J. doi: 10.1007/s00586-012-2281-4

17 Schizas C, Tzinieris N, Tsiridis E, Kosmopoulos V (2009) Min-imally invasive versus open transforaminal lumbar interbody fusion: evaluating initial experience. Int Orthop 33:1683–1688

18 Lau D, Lee JG, Han SJ, Lu DC, Chou D (2011) Complications and perioperative factors associated with learning the techniqueof minimally invasive transforaminal lumbar interbody fusion (TLIF). J Clin Neurosci 18:624–627

19.Egger M, Smith GD, Phillips AN. Meta-analysis: principles and procedures.British Medical Journal.1997;315(7121):1533–1537.

20.Egger M, Smith GD. Meta-analysis. Potentials and promise.British Medical Journal.1997;315(7119):1371–1374.

21.Cook DJ, Mulrow CD, Haynes RB. Systematic reviews: synthesis of best evidence for clinical decisions.Annals of Internal Medicine.1997;126(5):376–380.

22.Bero LA, Jadad AR. How consumers and policymakers can use systematic reviews for decision making.Annals of Internal Medicine.1997;127(1):37–42.

23 Chrastil J, Patel AA (2012) Complications associated with pos-terior and transforaminal lumbar interbody fusion. J Am Acad Orthop Surg 20:283–291

24.Slim K, Nini E, Forestier D, et al.Methodological index for non-randomized studies (min-ors): development and validation of a new instrument. ANZ J Surg .2003,73:712–716

25.Detsky AS, Naylor CD, O’Rourke K, et al.Incorporating variations in the quality of individual ran-domized trials into meta-analysis. J Clin Epidemiol 1992,45:255–265

26.Higgins JPT, Green S. Cochrane handbook for systematic reviews of interventions version 5.1. 0.The Cochrane Collaboration.2011

27 Zhang Shaodong ,Wang Chen,Chen Hui,et al. Priliminary experiencesin minimallyinvasive transforaminal lumbar interbodyfusion.Chin J Surg.2009,47(2):112-115.

28 Wang Jian, Zhou Yue, Zhang Zheng-feng, et al. Comparison of one-level minimally invasive and open transforaminal lumbar interbody fusion in degenerative and isthmic spondylolisthesis grades1 and 2. Eur Spine J,2010. 19(10): 1780-1784.

29 Fan Shunwu, Zhao Xing. Zhao Fengdong, et al. Minimally invasive transforaminal lumbar interbody fusion for the treatment of degenerative lumbar diseases. Spine, 2010, 35(17):1615-1620.

30 Wang Jian, Zhou Yue, Zhang Zheng-feng, et al. Minimally invasive or open transforaminal lumbar interbody fusion as revision surgery for patients previously treated by open discectomy and decompression of the lumbar spine.Eur Spine J.2011;20:623–628.

31 Dong Hai-tao, Li Hai-peng, Li Qiu-qun, et al.Comparative study on the clinical

effect of minimally invasive transforaminal lumbar interbody fusion and open operation in the treatment of lumbar spondylolisthesis. HaiNan Medical Journal.2012,23(14):39-41.

32 Xu hui,Xiao Lijun,Chen Wengui.Minimally invasive percutaneous transforaminal lumbar interbody fusion and open operation for treatment of lumbar spondylolisthesis Clinical study .HeBei Medical Journal.2013,19(1):48-51.

33 WangHong-Ii, Lii Fei-zhou, JIANG Jian-yuan, et al. Minimally invasive lumbar interbody fusion via MAST Quadrant retractor versus open surgery: a prospective randomized clinical trial[J]. Chin Med J, 2011, 124(23): 3868-3874.

34 Zhang Hailong,Gu Xin,He ShiSheng, et al. Minimally invasive percutaneous transforaminal lumbar interbody fusion versus posterior open surgery in treatment of lumbar spondylolisthesis .Chin J Orthop.2011,31(10):1088-1092.

35 Liang Bowei, YIN Guoqian, ZHAO Jinmin.Minimally invasive transforaminal lumbar interbody fusion for the treatment of degenerative lumbar instability,Chinese Journal of Reparative and Reconstructive Surgery,2011,25(12):1449-1454.

36 Zhang Quan, MAO Keya, WANG Bo, et al. Therapeutic effect comparison of minimally invasive surgery and open transforaminal lumbar interbody fusion in treatment of obese patients with lumbar intervertebral disc.Acad J Chin PLA Med Sch.2015,36(7):643-646.

37 Liu Dapeng,Liu Xiaotan,Xu Haibin , et al. Minimally invasive transforaminal lumbar interbody fusion for the treatment of degenerative lumbar spinal stenosis by X-Tube system.Chinese Journal of modern medicine.2014,24(21):54-59.

38 Zheng yang,Li Weishi,Chen Zhongqiang,et al. The minimally invasive posterior transforaminal lumbar interbody fusion verous open transforaminal lumbar interbody fusion in the treatment of single level lumbar degenerative disease .Comparison of the clinical efficacy of minimally invasive and open lumbar interbody fusion in the treatment of lumbar degenerative disease of lumbar vertebra.Chinese Journal of spine and spinal cord.2014,24(12):1064-1071.

39 Wang Jian, Zhou Yue, Zhang Zheng-feng, et al.Clinical study on lumbar spondylolisthesis treated by minimally invasive transforaminal lumbar interbody fusion .Chin J Surg.2011,49(12):1076-1080.

40.Harms J, Rolinger H. A one-stage procedure in operative treatment of spondylolisthesis: dorsal traction-reposition and anterior fusion.Zeitschrift fur Orthopadie und Ihre Grenzgebiete.1982;120(3):343–347.

41.Peng CWB, Yue WM, Poh SY, Yeo W, Tan SB. Clinical and radiological outcomes of minimally invasive versus open transforaminal lumbar interbody fusion.Spine.2009;34(13):1385–1389.

42.Park Y, Ha JW. Comparison of one-level posterior lumbar interbody fusion performed with a minimally invasive approach or a traditional open approach.Spine.2007;32(5):537–543.

43.Park P, Foley KT. Minimally invasive transforaminal lumbar interbody fusion with reduction of spondylolisthesis: technique and outcomes after a minimum of 2 years’ follow-up.Neurosurgical Focus.2008;25(2, article E16)

44.Lee KH, Yue WM, Yeo W, Soeharno H, Tan SB. Clinical and radiological outcomes of open versus minimally invasive transforaminal lumbar interbody fusion.European Spine Journal.2012;21(11):2265–2270

45.Lee CK, Park JY, Zhang HY. Minimally invasive transforaminal lumbar interbody fusion using a single interbody cage and a tubular retraction system: technical tips, and perioperative, radiologic and clinical outcomes.Journal of Korean Neurosurgical Society.2010;48(3):219–224.

46.Nai-Feng Tian,Yao-Sen Wu,Xiao-Lei Zhang, et al.Minimally invasive versus open transforaminal lumbar interbody fusion: a meta-analysis based on the current evidence.Eur Spine J. 2013 Aug; 22(8): 1741–1749.