British Journal of Neurosurgery
ISSN: 0268-8697 (Print) 1360-046X (Online) Journal homepage: http://www.tandfonline.com/loi/ibjn20
Anterior lumbar interbody fusion versus transforaminal lumbar interbody fusion – systematic review and meta-analysis Kevin Phan, Ganesha K. Thayaparan & Ralph J. Mobbs To cite this article: Kevin Phan, Ganesha K. Thayaparan & Ralph J. Mobbs (2015) Anterior lumbar interbody fusion versus transforaminal lumbar interbody fusion – systematic review and metaanalysis, British Journal of Neurosurgery, 29:5, 705-711, DOI: 10.3109/02688697.2015.1036838 To link to this article: https://doi.org/10.3109/02688697.2015.1036838
Published online: 12 May 2015.
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Date: 02 December 2017, At: 08:12
British Journal of Neurosurgery, October 2015; 29(5): 705–711 © 2015 The Neurosurgical Foundation ISSN: 0268-8697 print / ISSN 1360-046X online DOI: 10.3109/02688697.2015.1036838
ORIGINAL ARTICLE
Anterior lumbar interbody fusion versus transforaminal lumbar interbody fusion – systematic review and meta-analysis Kevin Phan, Ganesha K. Thayaparan & Ralph J. Mobbs
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Department of Neurosurgery, Neuro Spine Clinic, Prince of Wales Private Hospital, New South Wales, Australia and NeuroSpine Surgery Research Group (NSURG), Sydney, Australia
Abstract Purpose. To assess the clinical and radiographic outcomes and complications of anterior lumbar interbody fusion (ALIF) versus transforaminal lumbar interbody fusion (TLIF). Methods. A systematic literature search was conducted from six electronic databases. The relative risk and weighted mean difference (WMD) were used as statistical summary effect sizes. Results. Fusion rates (88.6% vs. 91.9%, P 0.23) and clinical outcomes were comparable between ALIF and TLIF. ALIF was associated with restoration of disk height (WMD, 2.71 mm, P 0.01), segmental lordosis (WMD, 2.35, P 0.03), and whole lumbar lordosis (WMD, 6.33, P 0.03). ALIF was also associated with longer hospitalization (WMD, 1.8 days, P 0.01), lower dural injury (0.4% vs. 3.8%, P 0.05) but higher blood vessel injury (2.6% vs. 0%, P 0.04). Conclusions. ALIF and TLIF appear to have similar success and clinical outcomes, with different complication profiles. ALIF may be associated with superior restoration of disk height and lordosis, but requires further validation in future studies.
Both ALIF and TLIF approaches involve removal of the degenerated disk, insertion of a cage and allograft with distracted adjacent vertebral segments, and finally followed by pedicle screw insertion and instrumentation to help improve spinal stability. Specifically, the ALIF approach offers several advantages, including better access to the central spinal canal and disk space, thus allowing adequate distraction to create lordosis.5,6 However, the anterior midline approach increases risk of injury or surgical trauma to nearby major vessel, uterus damage, ileus muscle damage, and risks of retrograde ejaculation.7,8 In contrast, the TLIF approach allows easier access to posterior structures including the lamina, ligamentum flavum, and facet joints.4 It allows simultaneous posterior instrumentation, while reducing soft tissue and paraspinal muscle dissection. However, TLIF also has known associated risks including its unilateral approach and poor decompression of the opposite root, as well as incomplete disk removal.9,10 The current evidence comparing ALIF and TLIF approaches are mostly confined to retrospective observational studies, and to date, there has still been no prospective, double-blinded, randomized controlled trials investigating these techniques. In order to best assess the relative benefits and risks of ALIF and TLIF based on the available evidence, a systematic review and meta-analysis was conducted.
Keywords: ALIF; anterior lumbar interbody fusion; fusion; lumbar spondylosis; TLIF; transforaminal lumbar interbody fusion
Introduction Degenerative disk disease and spinal deformities are increasingly common in the elderly population, with patients often presenting with back pain, radicular pain, or stiffness which severely affects the ability to work and quality of life.1,2 Carefully selected patients are suitable for surgical intervention in the form of interbody fusion to improve symptoms and spinal stability. Over time, several different fusion approaches have been developed, including anterior lumbar interbody fusion (ALIF),3 transforaminal lumbar interbody fusion (TLIF),4 and more recently, the advent of minimally invasive approaches.
Methods Literature search strategy Systematic literature searches were performed in six electronic databases, including Ovid Medline, PubMed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, ACP Journal Club, and Database of Abstracts of Review of Effectiveness from their data of inception to December 2014. To achieve the maximum sensitivity
Correspondence: Dr. Ralph J. Mobbs, Department of Neurosurgery, Neuro Spine Clinic, Suite 7a, Level 7 Prince of Wales Private Hospital, Barker Street, Randwick, New South Wales 2031, Australia. Tel: 61 2 9650 4766. E-mail: [email protected] Received for publication 4 January 2015; accepted 29 March 2015
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K. Phan & R. J. Mobbs 706 of the search strategy, we combined variants of the terms: “anterior lumbar interbody fusion” OR “ALIF” AND “transforaminal lumbar interbody fusion” OR “TLIF” AND “lumbar spondylosis” as either key words or MeSH terms. The reference lists of all retrieved articles were reviewed for further identification of potentially relevant studies, assessed using the inclusion and exclusion criteria.
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Selection criteria Eligible comparative studies for the present systematic review and meta-analysis included those in which patient cohorts comparing ALIF versus TLIF approaches for spinal surgery. When institutions published duplicate studies with accumulating numbers of patients or increased lengths of follow-up, only the most complete reports were included for quantitative assessment at each time interval. Reference lists were also hand-searched for further relevant studies. All publications were limited to those involving human subjects and in the English language. Abstracts, case reports, conference presentations, editorials, reviews, and expert opinions were excluded.
Table I. Study characteristics. Study First author Year design
n (ALIF)
n (TLIF)
Hacker
1997
R, OS
21
54
Ray Hee
1997 2001
R, OS R, OS
25 53
25 111
Whitecloud
2001
R, OS
40
40
Villavicencio
2006
R, OS
43
124
Hsieh
2007
R, OS
32
25
Crandall
2009
P, OS
20
20
Faundez
2009
R, OS
68
65
Kim
2009
R, OS
48
46
Kim
2010
R, OS
86
42
Dorward
2013
R, OS
42
42
Watkins
2014
R, OS
131
37
Data extraction and critical appraisal The primary outcome of interest included fusion rates, and operative, radiographic, and clinical outcomes. Operative outcomes comprised operation duration, blood loss, and hospital stay; radiographic outcomes comprised disk height, segmental lordosis, and whole lumbar lordosis; clinical outcomes comprised Oswestry Disability Index (ODI), Visual Analog Scale (VAS) (leg), and VAS (back) scores. Postoperative complication endpoints included dural injury, allograft malposition, pedicle malposition, neurological deficit, infections, and blood vessel injury. When exact mean and standard deviations (SDs) were not reported, these values were estimated from available graphs. All data were extracted from article texts, tables, and figures. Two investigators independently reviewed and assessed the quality of each retrieved article. Discrepancies between the reviewers were resolved by discussion and consensus.
Statistical analysis Clinical outcomes were assessed using standard meta-analysis techniques, with the relative risk (RR) used as a summary
Patient indication Low back pain NR Degenerative disk disease, herniation, spinal stenosis, spondylolisthesis, degenerative scoliosis, and pseudoarthrosis Degenerative disk disease, failed back surgery syndrome, isthmic spondylolisthesis, and degenerative spondylolisthesis Painful degenerative disk disease Spondylosis and spondylolisthesis Degenerative lumbar stenosis One- or two-level lumbar symptomatic disk degeneration Adult low-grade isthmic spondylolisthesis Unstable isthmic spondylolisthesis Adult spinal deformity, either scoliosis, kyphosis, sagittal imbalance, or prior surgery requiring multilevel reconstruction Spinal deformity or spondylolisthesis requiring sagittal correction
ALIF procedure
TLIF procedure
ALIFposterolateral fusionpedicle screw instrumentation NR ALIFposterolateral or intertransverse process fusion pedicle screw
TLIFposterolateral fusionpedicle screw instrumentation NR TLIFposterolateral or intertransverse process fusion pedicle screw
NR
Follow-up
ALIFposterolateral fusionpedicle screw instrumentation
TLIFposterolateral fusionpedicle screw instrumentation
NR
ALIFposterolateral fusion ALIF
Mini or open-TLIF
NR
TLIF
ALIFposterior instrumentation ALIFposterolateral fusionposterior fixation Mini-ALIF with percutaneous pedicle screw fixation Instrumented mini-ALIF ALIF
TLIFposterior instrumentation TLIFposterolateral fusionposterior fixation Mini-TLIF with percutaneous pedicle screw fixation Instrumented mini-TLIF TLIF
ALIF 45.7 m, TLIF 44.1 m 38 m
ALIFpedicle screws
TLIFpedicle screws
NR ALIF 7.7 m, TLIF 2.7 m
ALIF 34 m, TLIF 32 m ALIF 32.6 m, TLIF 29.7 m 2y 2y
19.2 m
R, retrospective; OS, observational study; NR, not reported; ALIF, anterior lumbar interbody fusion; TLIF, transforaminal lumbar interbody fusion; m, month; y, year.
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ALIF versus TLIF: Systematic review 707 statistic.11 Both fixed- and random-effect models were tested and used to calculate the RR or weighted mean differences (WMDs) for the surgical literature. Since similar results were obtained, only results of the random-effect model are presented. c2 tests were used to study heterogeneity between trials. I2 statistic was used to estimate the percentage of total variation across studies, owing to heterogeneity rather than chance, with values greater than 50% considered as substantial heterogeneity. All P values were 2-sided. All statistical analysis was conducted with Review Manager Version 5.2.2 (Cochrane Collaboration, Software Update, Oxford, UK).
Results
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Literature search The literature search from six electronic databases identified 239 relevant articles for the present systematic review. After application of the inclusion and exclusion criteria, a final selection of 12 articles9,10,12–21 were included in the metaanalysis. All included studies were retrospective, observational studies with the exception of the study by Crandall et al., which was a prospective, non-randomized study. A total of 609 ALIF patients and 631 TLIF patients were included for analysis. Patient indication, ALIF procedure, TLIF procedure, and mean follow-up duration are described in Table I.
Fusion rates Eight studies9,10,13–16,19,21 were identified which reported fusion rates. There were no significant differences between ALIF and TLIF cohorts in terms of fusion rates (88.6% vs. 91.9%; RR, 0.97; 95% confidence interval [CI], 0.92, 1.02; P 0.23). No significant heterogeneity was detected (I2 31%; P 0.18). These results are summarized in Fig. 1.
Operation parameters Eight studies reported operative time (Table II). Due to incomplete reporting of standard deviations, a metaanalysis and forest plot could only be performed on four of the included studies.13,15,19,21 From 417 patients, there was no significant difference detected between ALIF and TLIF groups in terms of operative duration (WMD, 28.52 min; 95% CI, 62.18, 119.21; P 0.54), with significant heterogeneity detected (I2 98%; P 0.00001). From 5 studies,13,15,18,19,21
Study or Subgroup Hacker 1997 Hee 2001 Hsieh 2007 Crandall 2009 Faundez 2009 Kim 2009 Kim 2010 Dorward 2013
ALIF TLIF Events Total Events Total Weight 4.4% 54 53 21 16 104 111 13.1% 53 45 25 25.1% 25 32 32 3.8% 20 18 20 16 7.8% 65 50 68 56 46 20.6% 45 48 45 42 13.1% 37 86 81 42 12.1% 40 42 37
blood loss was also similar between ALIF and TLIF cohorts (WMD, 89 mL; 95% CI, 271.45, 449.45; I2 91%; P 0.63). However, hospital stay was found to be significantly longer for the ALIF group compared with TLIF (WMD, 1.80 days; 95% CI, 0.38, 3.23; I2 91%; P 0.01).
Radiographic outcomes Radiographic outcomes are summarized in Table III. Only 3 studies reported radiographic outcomes in terms of disk height, segmental lordosis, and whole lumbar lordosis. Hsieh et al.9 reported greater disk height, segmental lordosis, and whole lumbar lordosis in the ALIF group compared with those in the TLIF group. Similar trends were also reported by Kim et al. in 200915 and 2010.14 Watkins et al.12 reported significantly higher segmental lordosis in the ALIF cohort compared to the TLIF cohort. Overall, there was significantly greater disk height (WMD, 2.71 mm; 95% CI, 0.56, 4.87; P 0.01), segmental lordosis (WMD, 3.25; 95% CI, 0.38, 6.13; P 0.03), and whole lumbar lordosis (WMD, 6.33; 95% CI, 0.56, 12.10; P 0.03) in the ALIF group versus TLIF group.
Clinical outcomes Functional clinical outcomes are reported in Table IV. There were 5 studies which compared functional outcomes between ALIF and TLIF cohorts. Three studies reported higher ODI scores in the ALIF group,14–16 while two studies reported lower ODI scores in the ALIF group.10,13 No significant difference was detected from the two studies which compared ALIF and TLIF cohorts in terms of leg VAS scores.14,15 From the three studies which reported back VAS scores, there was also no significant difference between ALIF and TLIF cohorts.14–16
Complications Major complications are summarized in Fig. 2. The rates of dural injury were found to be significantly lower in the ALIF group compared with those in the TLIF group (0.4% vs. 3.8%; RR, 0.29; 95% CI, 0.08, 1.00; I2 0%; P 0.05). No significant heterogeneity was detected for dural injury outcomes. Neurological deficits were comparable between ALIF and TLIF groups (6.8% vs. 7.9%; RR, 1.00; 95% CI, 0.54, 1.84; I2 0%; P 1.00), with no significant heterogeneity detected in these outcomes. Blood vessel injury occurred significantly
Risk Ratio M-H, Random, 95% CI Year 0.78 [0.61, 0.99] 1997 0.91 [0.80, 1.03] 2001 1.00 [0.93, 1.07] 2007 0.89 [0.68, 1.16] 2009 1.07 [0.90, 1.27] 2009 0.96 [0.88, 1.04] 2009 1.07 [0.95, 1.21] 2010 0.93 [0.81, 1.05] 2013
405 100.0% 370 Total (95% CI) 372 Total events 328 Heterogeneity: Tau2 = 0.00; Chi2 = 10.21, df = 7 (P = 0.18); I2 = 31% Test for overall effect: Z = 1.19 (P = 0.23)
Risk Ratio M-H, Random, 95% CI
0.97 [0.92, 1.02] 0.7 0.85 1 1.2 1.5 Favours TLIF Favours ALIF
Fig. 1. Forest plot of fusion rates for ALIF versus TLIF.
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K. Phan & R. J. Mobbs 708 Table II. Operative outcomes. Operative time (min)
Blood loss (mL)
Hospital stay (d)
First author
ALIF
TLIF
ALIF
TLIF
ALIF
TLIF
Hacker Ray Hee Whitecloud Villavicencio
250 84 289 279.6 65.4 269 455
900 755 729 957.7 1036.5 969 (250–2800) 550
NR NR 285 189.9 51.6 NR 481 89 NR
300 248 280 808.4 678.9 489 (200–1850) 231 (mini-TLIF), 424 (open-TLIF) NR R 313 397.6 205.7 NR 2011 848 NR
5.33 1.11 5 9 6.7 6.1 (3–9) 7.2
Hsieh Crandall Faundez Kim Kim Dorward Watkins
120 34 159 172.5 48.7 213 255 (mini-TLIF), 222 (open-TLIF) NR NR 181 207.9 53.1 NR 595 168 NR
3.50 1.22 5 5.2 2.6 3.3 (2–4) 3.1 (mini-TLIF), 4.1 (open-TLIF) NR NR 4.3 8.5 3.7 NR 7.9 NR
NR NR 430 300.4 161.6 NR 1281 1009 NR
NR NR 5.1 7.4 2.8 NR 12.3 NR
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NR, not reported; ALIF, anterior lumbar interbody fusion; TLIF, transforaminal lumbar interbody fusion.
more frequently in the ALIF cohort compared with that in TLIF (2.6% vs. 0%; RR, 4.40; 95% CI, 1.07–18.20; I2 0%; P 0.04). However, there were no differences in infection rates between the ALIF and TLIF groups (4.9% vs. 4.3%; RR, 1.08; 95% CI, 0.35–3.35; I2 53%; P 0.89). No significant heterogeneity was detected for infection outcomes. No differences were detected between ALIF and TLIF cohorts in terms of allograft malposition (2.4% vs. 1.8%; RR, 1.35; 95% CI, 0.14, 13.18; I2 63%; P 0.80). There was also no difference between cohorts in terms of pedicle screw malposition (7.7% vs. 6.8%; RR, 1.46; 95% CI, 0.82, 2.59; I2 0%; P 0.20) (Fig. 3). Of the included studies, two articles reported rates of adjacent segment degeneration. In the study by Hsieh et al., 1 patient (3.1%) in the ALIF cohort developed adjacent segment degeneration compared with 0 patients in the TLIF group. In the study by Crandall et al., 5 patients (25%) in the ALIF group developed adjacent segment degeneration compared with 3 patients (15%) in the TLIF group.
Discussion In the present systematic review and meta-analysis, it was found that (1) fusion rates were comparable between ALIF and TLIF, (2) ALIF was associated with longer hospitalization, (3) ALIF may be associated with superior restoration of
Table III. Radiographic outcomes. Disk height (mm)
disk height, and segmental and whole lumbar lordosis, and (4) lower rates of dural injury but higher blood vessel injury in the ALIF group. Comparable fusion rates were found between ALIF versus TLIF approaches, suggesting that both techniques are efficacious in the treatment of degenerative disk disease and spinal deformity. In terms of their operative profiles, there were distinct differences between groups in terms of operative duration and estimated blood loss for either technique. Hacker et al.21 and Hee et al.19 reported significantly higher operative durations for ALIF compared with those for TLIF, which contrast with reports from Kim et al.15 and Dorward et al.13 suggesting that TLIF was associated with longer operative time. The differences in these trends likely stem from the heterogeneity in ALIF technique used between centers. For example, the operative time for ALIF in the Hacker et al.21 and Hee et al.19 centers comprised ALIF, posterolateral fusion, as well as pedicle screw instrumentation. This contrasts with Kim et al.15 which uses a minimally invasive ALIF approach, which may reduce operative duration through smaller incisions. Furthermore, differences in technical expertise and experience between surgeons of different centers may also account for the heterogeneity observed in terms of operative time. Similar trends were also observed for estimated blood loss, with significant heterogeneity between the studies. Further studies are required to adequately compare
Segmental lordosis (deg)
Whole lumbar lordosis (deg)
First author
ALIF
TLIF
ALIF
TLIF
ALIF
TLIF
Hacker Ray Hee Whitecloud Villavicencio Hsieh Crandall Faundez Kim Kim Dorward Watkins
NR NR NR NR NR 18 (16.3–19.6) NR NR 15.9 1.7 13.5 2.7 NR NR
NR NR NR NR NR 15.1 (9.6–20.5) NR NR 12.1 1.8 11.9 2.0 NR NR
NR NR NR NR NR 15.4 (13.6–17.2) NR NR 22.8 6.6 18.2 4.9 NR 20.2 8.0
NR NR NR NR NR 7.7 (6.3–9.1) NR NR 18.3 8.3 17.4 5.7 NR 15.2 8.0
NR NR NR NR NR 56.6 (53.3–59.9) NR NR 55.8 12.5 61.3 8.6 NR NR
NR NR NR NR NR 51.5 (47.9–55.1) NR NR 52.6 9.8 52.2 9.9 NR NR
NR, not reported; ALIF, anterior lumbar interbody fusion; TLIF, transforaminal lumbar interbody fusion.
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ALIF versus TLIF: Systematic review 709 Table IV. Clinical functional outcomes. ODI (%)
VAS (leg)
VAS (back)
First author
ALIF
TLIF
ALIF
TLIF
ALIF
TLIF
Hacker Ray Hee Whitecloud Villavicencio Hsieh Crandall Faundez Kim Kim
NR NR NR NR NR NR 28.2 (0–62) 33.5 (0–76) 23.2 18.1 21.5 18.5*, 19.5 10.7** 22.6 NR
NR NR NR NR NR NR 27.9 (8–56) 39.5 (0–76) 14.4 15.9 11.1 12.3*, 17.8 20.3** 33.3 NR
NR NR NR NR NR NR NR NR 2.7 2.6 2.1 2.3*, 1.9 2.1** NR NR
NR NR NR NR NR NR NR NR 2.2 2.4 2.2 2.1*, 2.3 2.8** NR NR
NR NR NR NR NR 3.3 3.31 (0–8) NR 2.9 2.4 2.7 2.4*, 1.8 1.3** NR NR
NR NR NR NR NR 3.4 3.59 (0–8) NR 2.3 2.6 2.1 2.6*, 2.8 2.8** NR NR
Dorward Watkins
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NR, not reported; ALIF, anterior lumbar interbody fusion; TLIF, transforaminal lumbar interbody fusion. *L4/5; **L5/S1.
Study or Subgroup Dural injury Hee 2001 Whitecloud 2001 Hsieh 2007 Kim 2009 Faundez 2009 Subtotal (95% CI)
ALIF TLIF Events Total Events Total Weight 1 0 0 0 0
53 40 32 48 68 241
5 2 1 1 2
111 34.6% 40 17.2% 25 15.6% 46 15.4% 65 17.1% 287 100.0%
Risk Ratio M-H, Random, 95% CI Year 0.42 [0.05, 3.50] 0.20 [0.01, 4.04] 0.26 [0.01, 6.18] 0.32 [0.01, 7.65] 0.19 [0.01, 3.91] 0.29 [0.08, 1.00]
2001 2001 2007 2009 2009
0.95 [0.35, 2.60] 1.60 [0.57, 4.52] 1.00 [0.07, 14.90] 0.32 [0.01, 7.65] 0.60 [0.15, 2.35] 1.00 [0.54, 1.84]
2001 2006 2009 2009 2013
7.50 [0.32, 177.17] 3.00 [0.13, 71.51] 8.52 [0.35, 205.38] 2.88 [0.12, 68.88] 3.00 [0.13, 71.61] 4.40 [1.07, 18.20]
1997 2001 2006 2009 2013
7.50 [0.32, 177.17] 2.51 [0.80, 7.86] 5.77 [1.09, 30.38] 0.16 [0.01, 3.14] 0.32 [0.01, 7.65] 0.14 [0.01, 2.60] 0.48 [0.12, 1.83] 1.08 [0.35, 3.35]
1997 2001 2006 2007 2009 2009 2009
Risk Ratio M-H, Random, 95% CI
11 Total events 1 Heterogeneity: Tau2 = 0.00; Chi2 = 0.25, df = 4 (P = 0.99); I2 = 0% Test for overall effect: Z = 1.96 (P = 0.05) Neurological deficity Hee 2001 Villavicencio 2006 Crandall 2009 Kim 2009 Dorward 2013 Subtotal (95% CI)
5 5 1 0 3
53 43 20 48 42 206
11 9 1 1 5
111 36.8% 124 34.6% 5.1% 20 3.7% 46 42 19.9% 343 100.0%
27 Total events 14 Heterogeneity: Tau2 = 0.00; Chi2 = 1.85, df = 4 (P = 0.76); I2 = 0% Test for overall effect: Z = 0.00 (P = 1.00) Blood vessel injury Hacker 1997 Whitecloud 2001 Villavicencio 2006 Kim 2009 Dorward 2013 Subtotal (95% CI)
1 1 1 1 1
21 40 43 48 42 194
0 0 0 0 0
54 20.1% 40 20.0% 124 19.9% 46 20.0% 42 20.0% 306 100.0%
0 5 Total events Heterogeneity: Tau2 = 0.00; Chi2 = 0.46, df = 4 (P = 0.98); I2 = 0% Test for overall effect: Z = 2.05 (P = 0.04) Infection Hacker 1997 Hee 2001 Villavicencio 2006 Hsieh 2007 Kim 2009 Crandall 2009 Faundez 2009 Subtotal (95% CI)
1 6 4 0 0 0 3
21 53 43 32 48 20 68 285
0 5 2 2 1 3 6
9.0% 54 111 23.0% 124 18.2% 9.7% 25 8.9% 46 20 10.1% 65 21.1% 445 100.0%
19 14 Total events Heterogeneity: Tau2 = 1.10; Chi2 = 12.80, df = 6 (P = 0.05); I2 = 53% Test for overall effect: Z = 0.14 (P = 0.89) 0.005 0.1 1 10 200 Favours ALIF Favours TLIF
Fig. 2. Forest plot of complications including dural injury, neurological deficit, blood vessel injury, and infections for ALIF versus TLIF.
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K. Phan & R. J. Mobbs
Study or Subgroup Allograft malposition Hee 2001 Villavicencio 2006 Faundez 2009 Dorward 2013 Subtotal (95% CI)
ALIF Events Total 3 2 0 0
53 43 68 42 206
TLIF Events Total Weight 1 0 3 2
111 28.9% 124 23.5% 65 24.0% 42 23.6% 342 100.0%
Risk Ratio M-H, Random, 95% CI Year 6.28 [0.67, 58.98] 14.20 [0.70, 290.16] 0.14 [0.01, 2.59] 0.20 [0.01, 4.04] 1.35 [0.14, 13.18]
2001 2006 2009 2013
1.57 [0.36, 6.77] 1.24 [0.51, 3.01] 0.96 [0.06, 14.87] 0.18 [0.01, 4.33] 2.20 [0.84, 5.78] 1.46 [0.82, 2.59]
2001 2006 2009 2010 2013
Risk Ratio M-H, Random, 95% CI
5 Total events 6 Heterogeneity: Tau2 = 3.39; Chi2 = 8.09, df = 3 (P = 0.04); I2 = 63% Test for overall effect: Z = 0.26 (P = 0.80) Pedicle malposition
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Hee 2001 Villavicencio 2006 Kim 2009 Kim 2010 Dorward 2013 Subtotal (95% CI )
3 6 1 0 11
53 43 48 86 42 272
4 14 1 1 5
111 15.5% 124 41.6% 46 4.4% 46 3.3% 42 35.3% 369 100.0%
Total events 21 25 Heterogeneity: Tau2 = 0.00; Chi2 = 2.60, df = 4 (P = 0.63); I2 = 0% Test for overall effect: Z = 1.29 (P = 0.20) 0.001 0.1 1 10 1000 Favours ALIF Favours TLIF
Fig. 3. Forest plot for allograft and pedicle malposition for ALIF versus TLIF.
operative duration and blood loss between ALIF and TLIF approaches. However, from the present systematic review, a significant reduction in hospitalization was noted in the TLIF group compared with that in ALIF group. One explanation for this observation may be that the anterior ALIF approach also requires posterior access for pedicle instrumentation, which may translate increased surgical trauma and hospital stay required compared with TLIF, whereas the posterior procedure allows access for both disk removal and instrumentation.22 Radiographic and clinical functional outcomes were reported by only few of the included comparative studies. Previous studies have suggested that ALIF is superior to TLIF in terms of disk height and lumbar lordosis restoration. Results from the present meta-analysis also support this notion, with higher disk height, segmental lordosis, and whole lumbar lordosis noted across studies9,12,14,15 in the ALIF cohorts compared with those in TLIF cohorts. These results suggest that ALIF may be a better approach for restoration of foraminal height, local disk angle, and lumbar lordosis. One justification for the observed trends is the nature of the ALIF procedure, which involves distraction of adjacent vertebral bodies to allow insertion of an interbody graft. This distraction may also result in increased disk height and improve lumbar lordosis.3,23,24 Restoration of these radiographic features is important for improved sagittal balance in these patients. Functional outcomes including ODI and VAS leg/back pain scores were poorly reported from the included studies. Overall, there was no notable difference between ALIF and TLIF approaches in functional scores, suggesting that surgical techniques are effective in back pain and radiculopathy management. These trends require further validation in prospective, adequately powered studies. Complication rates for ALIF and TLIF were mostly comparable except for two exceptions. There was a notable lower
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level of dural injury in the ALIF cohort compared with that in the TLIF cohort. This is most likely due to the nature of the anterior approach and anatomy of the vertebral body and spinal canal. The ALIF approach allows easier access and approach to the disk, which is anterior to the dura and hence limits direct contact between the surgeon and dura. In contrast, the TLIF approach requires retraction of nerve roots and opening the neural foramen on one side to access the disk space.4,13,22 Excess retraction force may translate into increased rates of dural tears or injury compared with the ALIF approach. Additionally, the present meta-analysis demonstrated that ALIF was associated with significantly higher blood vessel injury. This result is not surprising, given that the anterior technique involves exposure, manipulation, and mobilization of the iliac vessels, which increases the risk of bleeding via lacerations and thrombosis.7,8 Given the higher risk of vascular injury during ALIF, vascular surgical support should be readily available during an ALIF operation, should any vascular complications arise. The present systematic review and meta-analysis is limited by several constraints. Firstly, the majority of included studies were retrospective in design, which may introduce selection bias and undermine the validity of the presented results.11 The small sample sizes of included studies also limit the statistical power to distinguish between complication rates of ALIF versus TLIF groups. The heterogeneity of the ALIF and TLIF procedures between centers, as well as differing surgeon-specific technical expertise and experience, also limits the validity of the analyzed results. Specifically, ALIF was performed with posterior instrumentation in some studies, and without instrumentation in two studies.9,13 A subgroup analysis was performed to see whether any differences in outcomes were observed for ALIF with versus without posterior instrumentation; however, the lack of studies and statistical power precluded any meaningful conclusions.
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ALIF versus TLIF: Systematic review 711 Another major limitation is poor reporting of endpoints including radiographic and functional clinical outcomes, which means that definitive comparisons between ALIF and TLIF groups could not be concluded. Outcomes such as adjacent segment degeneration and disease were poorly reported, and should be addressed in future investigations. Prospective, multi-center registry studies of adequate statistical power may provide further evidence to conclusively assess the risks and benefits of ALIF versus TLIF procedures.
8. 9.
10.
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Conclusion In summary, both ALIF and TLIF appeared to be effective fusion techniques with similar fusion rates, operative duration, blood loss, and postoperative VAS and ODI pain scores. ALIF was associated superior disk height, segmental and lumbar lordosis restoration, and longer hospitalization. ALIF was also associated with fewer dural injuries but significantly higher rates of vascular injuries. These trends require further validation in prospective studies with adequate sample size and follow-up.
11.
12.
13.
14.
Acknowledgements None declared.
15.
Funding None. Declaration of interest: The authors report no declarations of interest. The authors alone are responsible for the content and writing of the paper.
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Anterior lumbar interbody fusion versus transforaminal lumbar interbody fusion – systematic review and meta-analysis Kevin Phan, Ganesha K. Thayaparan & Ralph J. Mobbs To cite this article: Kevin Phan, Ganesha K. Thayaparan & Ralph J. Mobbs (2015) Anterior lumbar interbody fusion versus transforaminal lumbar interbody fusion – systematic review and metaanalysis, British Journal of Neurosurgery, 29:5, 705-711, DOI: 10.3109/02688697.2015.1036838 To link to this article: https://doi.org/10.3109/02688697.2015.1036838
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Date: 02 December 2017, At: 08:12
British Journal of Neurosurgery, October 2015; 29(5): 705–711 © 2015 The Neurosurgical Foundation ISSN: 0268-8697 print / ISSN 1360-046X online DOI: 10.3109/02688697.2015.1036838
ORIGINAL ARTICLE
Anterior lumbar interbody fusion versus transforaminal lumbar interbody fusion – systematic review and meta-analysis Kevin Phan, Ganesha K. Thayaparan & Ralph J. Mobbs
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Department of Neurosurgery, Neuro Spine Clinic, Prince of Wales Private Hospital, New South Wales, Australia and NeuroSpine Surgery Research Group (NSURG), Sydney, Australia
Abstract Purpose. To assess the clinical and radiographic outcomes and complications of anterior lumbar interbody fusion (ALIF) versus transforaminal lumbar interbody fusion (TLIF). Methods. A systematic literature search was conducted from six electronic databases. The relative risk and weighted mean difference (WMD) were used as statistical summary effect sizes. Results. Fusion rates (88.6% vs. 91.9%, P 0.23) and clinical outcomes were comparable between ALIF and TLIF. ALIF was associated with restoration of disk height (WMD, 2.71 mm, P 0.01), segmental lordosis (WMD, 2.35, P 0.03), and whole lumbar lordosis (WMD, 6.33, P 0.03). ALIF was also associated with longer hospitalization (WMD, 1.8 days, P 0.01), lower dural injury (0.4% vs. 3.8%, P 0.05) but higher blood vessel injury (2.6% vs. 0%, P 0.04). Conclusions. ALIF and TLIF appear to have similar success and clinical outcomes, with different complication profiles. ALIF may be associated with superior restoration of disk height and lordosis, but requires further validation in future studies.
Both ALIF and TLIF approaches involve removal of the degenerated disk, insertion of a cage and allograft with distracted adjacent vertebral segments, and finally followed by pedicle screw insertion and instrumentation to help improve spinal stability. Specifically, the ALIF approach offers several advantages, including better access to the central spinal canal and disk space, thus allowing adequate distraction to create lordosis.5,6 However, the anterior midline approach increases risk of injury or surgical trauma to nearby major vessel, uterus damage, ileus muscle damage, and risks of retrograde ejaculation.7,8 In contrast, the TLIF approach allows easier access to posterior structures including the lamina, ligamentum flavum, and facet joints.4 It allows simultaneous posterior instrumentation, while reducing soft tissue and paraspinal muscle dissection. However, TLIF also has known associated risks including its unilateral approach and poor decompression of the opposite root, as well as incomplete disk removal.9,10 The current evidence comparing ALIF and TLIF approaches are mostly confined to retrospective observational studies, and to date, there has still been no prospective, double-blinded, randomized controlled trials investigating these techniques. In order to best assess the relative benefits and risks of ALIF and TLIF based on the available evidence, a systematic review and meta-analysis was conducted.
Keywords: ALIF; anterior lumbar interbody fusion; fusion; lumbar spondylosis; TLIF; transforaminal lumbar interbody fusion
Introduction Degenerative disk disease and spinal deformities are increasingly common in the elderly population, with patients often presenting with back pain, radicular pain, or stiffness which severely affects the ability to work and quality of life.1,2 Carefully selected patients are suitable for surgical intervention in the form of interbody fusion to improve symptoms and spinal stability. Over time, several different fusion approaches have been developed, including anterior lumbar interbody fusion (ALIF),3 transforaminal lumbar interbody fusion (TLIF),4 and more recently, the advent of minimally invasive approaches.
Methods Literature search strategy Systematic literature searches were performed in six electronic databases, including Ovid Medline, PubMed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, ACP Journal Club, and Database of Abstracts of Review of Effectiveness from their data of inception to December 2014. To achieve the maximum sensitivity
Correspondence: Dr. Ralph J. Mobbs, Department of Neurosurgery, Neuro Spine Clinic, Suite 7a, Level 7 Prince of Wales Private Hospital, Barker Street, Randwick, New South Wales 2031, Australia. Tel: 61 2 9650 4766. E-mail: [email protected] Received for publication 4 January 2015; accepted 29 March 2015
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K. Phan & R. J. Mobbs 706 of the search strategy, we combined variants of the terms: “anterior lumbar interbody fusion” OR “ALIF” AND “transforaminal lumbar interbody fusion” OR “TLIF” AND “lumbar spondylosis” as either key words or MeSH terms. The reference lists of all retrieved articles were reviewed for further identification of potentially relevant studies, assessed using the inclusion and exclusion criteria.
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Selection criteria Eligible comparative studies for the present systematic review and meta-analysis included those in which patient cohorts comparing ALIF versus TLIF approaches for spinal surgery. When institutions published duplicate studies with accumulating numbers of patients or increased lengths of follow-up, only the most complete reports were included for quantitative assessment at each time interval. Reference lists were also hand-searched for further relevant studies. All publications were limited to those involving human subjects and in the English language. Abstracts, case reports, conference presentations, editorials, reviews, and expert opinions were excluded.
Table I. Study characteristics. Study First author Year design
n (ALIF)
n (TLIF)
Hacker
1997
R, OS
21
54
Ray Hee
1997 2001
R, OS R, OS
25 53
25 111
Whitecloud
2001
R, OS
40
40
Villavicencio
2006
R, OS
43
124
Hsieh
2007
R, OS
32
25
Crandall
2009
P, OS
20
20
Faundez
2009
R, OS
68
65
Kim
2009
R, OS
48
46
Kim
2010
R, OS
86
42
Dorward
2013
R, OS
42
42
Watkins
2014
R, OS
131
37
Data extraction and critical appraisal The primary outcome of interest included fusion rates, and operative, radiographic, and clinical outcomes. Operative outcomes comprised operation duration, blood loss, and hospital stay; radiographic outcomes comprised disk height, segmental lordosis, and whole lumbar lordosis; clinical outcomes comprised Oswestry Disability Index (ODI), Visual Analog Scale (VAS) (leg), and VAS (back) scores. Postoperative complication endpoints included dural injury, allograft malposition, pedicle malposition, neurological deficit, infections, and blood vessel injury. When exact mean and standard deviations (SDs) were not reported, these values were estimated from available graphs. All data were extracted from article texts, tables, and figures. Two investigators independently reviewed and assessed the quality of each retrieved article. Discrepancies between the reviewers were resolved by discussion and consensus.
Statistical analysis Clinical outcomes were assessed using standard meta-analysis techniques, with the relative risk (RR) used as a summary
Patient indication Low back pain NR Degenerative disk disease, herniation, spinal stenosis, spondylolisthesis, degenerative scoliosis, and pseudoarthrosis Degenerative disk disease, failed back surgery syndrome, isthmic spondylolisthesis, and degenerative spondylolisthesis Painful degenerative disk disease Spondylosis and spondylolisthesis Degenerative lumbar stenosis One- or two-level lumbar symptomatic disk degeneration Adult low-grade isthmic spondylolisthesis Unstable isthmic spondylolisthesis Adult spinal deformity, either scoliosis, kyphosis, sagittal imbalance, or prior surgery requiring multilevel reconstruction Spinal deformity or spondylolisthesis requiring sagittal correction
ALIF procedure
TLIF procedure
ALIFposterolateral fusionpedicle screw instrumentation NR ALIFposterolateral or intertransverse process fusion pedicle screw
TLIFposterolateral fusionpedicle screw instrumentation NR TLIFposterolateral or intertransverse process fusion pedicle screw
NR
Follow-up
ALIFposterolateral fusionpedicle screw instrumentation
TLIFposterolateral fusionpedicle screw instrumentation
NR
ALIFposterolateral fusion ALIF
Mini or open-TLIF
NR
TLIF
ALIFposterior instrumentation ALIFposterolateral fusionposterior fixation Mini-ALIF with percutaneous pedicle screw fixation Instrumented mini-ALIF ALIF
TLIFposterior instrumentation TLIFposterolateral fusionposterior fixation Mini-TLIF with percutaneous pedicle screw fixation Instrumented mini-TLIF TLIF
ALIF 45.7 m, TLIF 44.1 m 38 m
ALIFpedicle screws
TLIFpedicle screws
NR ALIF 7.7 m, TLIF 2.7 m
ALIF 34 m, TLIF 32 m ALIF 32.6 m, TLIF 29.7 m 2y 2y
19.2 m
R, retrospective; OS, observational study; NR, not reported; ALIF, anterior lumbar interbody fusion; TLIF, transforaminal lumbar interbody fusion; m, month; y, year.
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ALIF versus TLIF: Systematic review 707 statistic.11 Both fixed- and random-effect models were tested and used to calculate the RR or weighted mean differences (WMDs) for the surgical literature. Since similar results were obtained, only results of the random-effect model are presented. c2 tests were used to study heterogeneity between trials. I2 statistic was used to estimate the percentage of total variation across studies, owing to heterogeneity rather than chance, with values greater than 50% considered as substantial heterogeneity. All P values were 2-sided. All statistical analysis was conducted with Review Manager Version 5.2.2 (Cochrane Collaboration, Software Update, Oxford, UK).
Results
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Literature search The literature search from six electronic databases identified 239 relevant articles for the present systematic review. After application of the inclusion and exclusion criteria, a final selection of 12 articles9,10,12–21 were included in the metaanalysis. All included studies were retrospective, observational studies with the exception of the study by Crandall et al., which was a prospective, non-randomized study. A total of 609 ALIF patients and 631 TLIF patients were included for analysis. Patient indication, ALIF procedure, TLIF procedure, and mean follow-up duration are described in Table I.
Fusion rates Eight studies9,10,13–16,19,21 were identified which reported fusion rates. There were no significant differences between ALIF and TLIF cohorts in terms of fusion rates (88.6% vs. 91.9%; RR, 0.97; 95% confidence interval [CI], 0.92, 1.02; P 0.23). No significant heterogeneity was detected (I2 31%; P 0.18). These results are summarized in Fig. 1.
Operation parameters Eight studies reported operative time (Table II). Due to incomplete reporting of standard deviations, a metaanalysis and forest plot could only be performed on four of the included studies.13,15,19,21 From 417 patients, there was no significant difference detected between ALIF and TLIF groups in terms of operative duration (WMD, 28.52 min; 95% CI, 62.18, 119.21; P 0.54), with significant heterogeneity detected (I2 98%; P 0.00001). From 5 studies,13,15,18,19,21
Study or Subgroup Hacker 1997 Hee 2001 Hsieh 2007 Crandall 2009 Faundez 2009 Kim 2009 Kim 2010 Dorward 2013
ALIF TLIF Events Total Events Total Weight 4.4% 54 53 21 16 104 111 13.1% 53 45 25 25.1% 25 32 32 3.8% 20 18 20 16 7.8% 65 50 68 56 46 20.6% 45 48 45 42 13.1% 37 86 81 42 12.1% 40 42 37
blood loss was also similar between ALIF and TLIF cohorts (WMD, 89 mL; 95% CI, 271.45, 449.45; I2 91%; P 0.63). However, hospital stay was found to be significantly longer for the ALIF group compared with TLIF (WMD, 1.80 days; 95% CI, 0.38, 3.23; I2 91%; P 0.01).
Radiographic outcomes Radiographic outcomes are summarized in Table III. Only 3 studies reported radiographic outcomes in terms of disk height, segmental lordosis, and whole lumbar lordosis. Hsieh et al.9 reported greater disk height, segmental lordosis, and whole lumbar lordosis in the ALIF group compared with those in the TLIF group. Similar trends were also reported by Kim et al. in 200915 and 2010.14 Watkins et al.12 reported significantly higher segmental lordosis in the ALIF cohort compared to the TLIF cohort. Overall, there was significantly greater disk height (WMD, 2.71 mm; 95% CI, 0.56, 4.87; P 0.01), segmental lordosis (WMD, 3.25; 95% CI, 0.38, 6.13; P 0.03), and whole lumbar lordosis (WMD, 6.33; 95% CI, 0.56, 12.10; P 0.03) in the ALIF group versus TLIF group.
Clinical outcomes Functional clinical outcomes are reported in Table IV. There were 5 studies which compared functional outcomes between ALIF and TLIF cohorts. Three studies reported higher ODI scores in the ALIF group,14–16 while two studies reported lower ODI scores in the ALIF group.10,13 No significant difference was detected from the two studies which compared ALIF and TLIF cohorts in terms of leg VAS scores.14,15 From the three studies which reported back VAS scores, there was also no significant difference between ALIF and TLIF cohorts.14–16
Complications Major complications are summarized in Fig. 2. The rates of dural injury were found to be significantly lower in the ALIF group compared with those in the TLIF group (0.4% vs. 3.8%; RR, 0.29; 95% CI, 0.08, 1.00; I2 0%; P 0.05). No significant heterogeneity was detected for dural injury outcomes. Neurological deficits were comparable between ALIF and TLIF groups (6.8% vs. 7.9%; RR, 1.00; 95% CI, 0.54, 1.84; I2 0%; P 1.00), with no significant heterogeneity detected in these outcomes. Blood vessel injury occurred significantly
Risk Ratio M-H, Random, 95% CI Year 0.78 [0.61, 0.99] 1997 0.91 [0.80, 1.03] 2001 1.00 [0.93, 1.07] 2007 0.89 [0.68, 1.16] 2009 1.07 [0.90, 1.27] 2009 0.96 [0.88, 1.04] 2009 1.07 [0.95, 1.21] 2010 0.93 [0.81, 1.05] 2013
405 100.0% 370 Total (95% CI) 372 Total events 328 Heterogeneity: Tau2 = 0.00; Chi2 = 10.21, df = 7 (P = 0.18); I2 = 31% Test for overall effect: Z = 1.19 (P = 0.23)
Risk Ratio M-H, Random, 95% CI
0.97 [0.92, 1.02] 0.7 0.85 1 1.2 1.5 Favours TLIF Favours ALIF
Fig. 1. Forest plot of fusion rates for ALIF versus TLIF.
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K. Phan & R. J. Mobbs 708 Table II. Operative outcomes. Operative time (min)
Blood loss (mL)
Hospital stay (d)
First author
ALIF
TLIF
ALIF
TLIF
ALIF
TLIF
Hacker Ray Hee Whitecloud Villavicencio
250 84 289 279.6 65.4 269 455
900 755 729 957.7 1036.5 969 (250–2800) 550
NR NR 285 189.9 51.6 NR 481 89 NR
300 248 280 808.4 678.9 489 (200–1850) 231 (mini-TLIF), 424 (open-TLIF) NR R 313 397.6 205.7 NR 2011 848 NR
5.33 1.11 5 9 6.7 6.1 (3–9) 7.2
Hsieh Crandall Faundez Kim Kim Dorward Watkins
120 34 159 172.5 48.7 213 255 (mini-TLIF), 222 (open-TLIF) NR NR 181 207.9 53.1 NR 595 168 NR
3.50 1.22 5 5.2 2.6 3.3 (2–4) 3.1 (mini-TLIF), 4.1 (open-TLIF) NR NR 4.3 8.5 3.7 NR 7.9 NR
NR NR 430 300.4 161.6 NR 1281 1009 NR
NR NR 5.1 7.4 2.8 NR 12.3 NR
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NR, not reported; ALIF, anterior lumbar interbody fusion; TLIF, transforaminal lumbar interbody fusion.
more frequently in the ALIF cohort compared with that in TLIF (2.6% vs. 0%; RR, 4.40; 95% CI, 1.07–18.20; I2 0%; P 0.04). However, there were no differences in infection rates between the ALIF and TLIF groups (4.9% vs. 4.3%; RR, 1.08; 95% CI, 0.35–3.35; I2 53%; P 0.89). No significant heterogeneity was detected for infection outcomes. No differences were detected between ALIF and TLIF cohorts in terms of allograft malposition (2.4% vs. 1.8%; RR, 1.35; 95% CI, 0.14, 13.18; I2 63%; P 0.80). There was also no difference between cohorts in terms of pedicle screw malposition (7.7% vs. 6.8%; RR, 1.46; 95% CI, 0.82, 2.59; I2 0%; P 0.20) (Fig. 3). Of the included studies, two articles reported rates of adjacent segment degeneration. In the study by Hsieh et al., 1 patient (3.1%) in the ALIF cohort developed adjacent segment degeneration compared with 0 patients in the TLIF group. In the study by Crandall et al., 5 patients (25%) in the ALIF group developed adjacent segment degeneration compared with 3 patients (15%) in the TLIF group.
Discussion In the present systematic review and meta-analysis, it was found that (1) fusion rates were comparable between ALIF and TLIF, (2) ALIF was associated with longer hospitalization, (3) ALIF may be associated with superior restoration of
Table III. Radiographic outcomes. Disk height (mm)
disk height, and segmental and whole lumbar lordosis, and (4) lower rates of dural injury but higher blood vessel injury in the ALIF group. Comparable fusion rates were found between ALIF versus TLIF approaches, suggesting that both techniques are efficacious in the treatment of degenerative disk disease and spinal deformity. In terms of their operative profiles, there were distinct differences between groups in terms of operative duration and estimated blood loss for either technique. Hacker et al.21 and Hee et al.19 reported significantly higher operative durations for ALIF compared with those for TLIF, which contrast with reports from Kim et al.15 and Dorward et al.13 suggesting that TLIF was associated with longer operative time. The differences in these trends likely stem from the heterogeneity in ALIF technique used between centers. For example, the operative time for ALIF in the Hacker et al.21 and Hee et al.19 centers comprised ALIF, posterolateral fusion, as well as pedicle screw instrumentation. This contrasts with Kim et al.15 which uses a minimally invasive ALIF approach, which may reduce operative duration through smaller incisions. Furthermore, differences in technical expertise and experience between surgeons of different centers may also account for the heterogeneity observed in terms of operative time. Similar trends were also observed for estimated blood loss, with significant heterogeneity between the studies. Further studies are required to adequately compare
Segmental lordosis (deg)
Whole lumbar lordosis (deg)
First author
ALIF
TLIF
ALIF
TLIF
ALIF
TLIF
Hacker Ray Hee Whitecloud Villavicencio Hsieh Crandall Faundez Kim Kim Dorward Watkins
NR NR NR NR NR 18 (16.3–19.6) NR NR 15.9 1.7 13.5 2.7 NR NR
NR NR NR NR NR 15.1 (9.6–20.5) NR NR 12.1 1.8 11.9 2.0 NR NR
NR NR NR NR NR 15.4 (13.6–17.2) NR NR 22.8 6.6 18.2 4.9 NR 20.2 8.0
NR NR NR NR NR 7.7 (6.3–9.1) NR NR 18.3 8.3 17.4 5.7 NR 15.2 8.0
NR NR NR NR NR 56.6 (53.3–59.9) NR NR 55.8 12.5 61.3 8.6 NR NR
NR NR NR NR NR 51.5 (47.9–55.1) NR NR 52.6 9.8 52.2 9.9 NR NR
NR, not reported; ALIF, anterior lumbar interbody fusion; TLIF, transforaminal lumbar interbody fusion.
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ALIF versus TLIF: Systematic review 709 Table IV. Clinical functional outcomes. ODI (%)
VAS (leg)
VAS (back)
First author
ALIF
TLIF
ALIF
TLIF
ALIF
TLIF
Hacker Ray Hee Whitecloud Villavicencio Hsieh Crandall Faundez Kim Kim
NR NR NR NR NR NR 28.2 (0–62) 33.5 (0–76) 23.2 18.1 21.5 18.5*, 19.5 10.7** 22.6 NR
NR NR NR NR NR NR 27.9 (8–56) 39.5 (0–76) 14.4 15.9 11.1 12.3*, 17.8 20.3** 33.3 NR
NR NR NR NR NR NR NR NR 2.7 2.6 2.1 2.3*, 1.9 2.1** NR NR
NR NR NR NR NR NR NR NR 2.2 2.4 2.2 2.1*, 2.3 2.8** NR NR
NR NR NR NR NR 3.3 3.31 (0–8) NR 2.9 2.4 2.7 2.4*, 1.8 1.3** NR NR
NR NR NR NR NR 3.4 3.59 (0–8) NR 2.3 2.6 2.1 2.6*, 2.8 2.8** NR NR
Dorward Watkins
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NR, not reported; ALIF, anterior lumbar interbody fusion; TLIF, transforaminal lumbar interbody fusion. *L4/5; **L5/S1.
Study or Subgroup Dural injury Hee 2001 Whitecloud 2001 Hsieh 2007 Kim 2009 Faundez 2009 Subtotal (95% CI)
ALIF TLIF Events Total Events Total Weight 1 0 0 0 0
53 40 32 48 68 241
5 2 1 1 2
111 34.6% 40 17.2% 25 15.6% 46 15.4% 65 17.1% 287 100.0%
Risk Ratio M-H, Random, 95% CI Year 0.42 [0.05, 3.50] 0.20 [0.01, 4.04] 0.26 [0.01, 6.18] 0.32 [0.01, 7.65] 0.19 [0.01, 3.91] 0.29 [0.08, 1.00]
2001 2001 2007 2009 2009
0.95 [0.35, 2.60] 1.60 [0.57, 4.52] 1.00 [0.07, 14.90] 0.32 [0.01, 7.65] 0.60 [0.15, 2.35] 1.00 [0.54, 1.84]
2001 2006 2009 2009 2013
7.50 [0.32, 177.17] 3.00 [0.13, 71.51] 8.52 [0.35, 205.38] 2.88 [0.12, 68.88] 3.00 [0.13, 71.61] 4.40 [1.07, 18.20]
1997 2001 2006 2009 2013
7.50 [0.32, 177.17] 2.51 [0.80, 7.86] 5.77 [1.09, 30.38] 0.16 [0.01, 3.14] 0.32 [0.01, 7.65] 0.14 [0.01, 2.60] 0.48 [0.12, 1.83] 1.08 [0.35, 3.35]
1997 2001 2006 2007 2009 2009 2009
Risk Ratio M-H, Random, 95% CI
11 Total events 1 Heterogeneity: Tau2 = 0.00; Chi2 = 0.25, df = 4 (P = 0.99); I2 = 0% Test for overall effect: Z = 1.96 (P = 0.05) Neurological deficity Hee 2001 Villavicencio 2006 Crandall 2009 Kim 2009 Dorward 2013 Subtotal (95% CI)
5 5 1 0 3
53 43 20 48 42 206
11 9 1 1 5
111 36.8% 124 34.6% 5.1% 20 3.7% 46 42 19.9% 343 100.0%
27 Total events 14 Heterogeneity: Tau2 = 0.00; Chi2 = 1.85, df = 4 (P = 0.76); I2 = 0% Test for overall effect: Z = 0.00 (P = 1.00) Blood vessel injury Hacker 1997 Whitecloud 2001 Villavicencio 2006 Kim 2009 Dorward 2013 Subtotal (95% CI)
1 1 1 1 1
21 40 43 48 42 194
0 0 0 0 0
54 20.1% 40 20.0% 124 19.9% 46 20.0% 42 20.0% 306 100.0%
0 5 Total events Heterogeneity: Tau2 = 0.00; Chi2 = 0.46, df = 4 (P = 0.98); I2 = 0% Test for overall effect: Z = 2.05 (P = 0.04) Infection Hacker 1997 Hee 2001 Villavicencio 2006 Hsieh 2007 Kim 2009 Crandall 2009 Faundez 2009 Subtotal (95% CI)
1 6 4 0 0 0 3
21 53 43 32 48 20 68 285
0 5 2 2 1 3 6
9.0% 54 111 23.0% 124 18.2% 9.7% 25 8.9% 46 20 10.1% 65 21.1% 445 100.0%
19 14 Total events Heterogeneity: Tau2 = 1.10; Chi2 = 12.80, df = 6 (P = 0.05); I2 = 53% Test for overall effect: Z = 0.14 (P = 0.89) 0.005 0.1 1 10 200 Favours ALIF Favours TLIF
Fig. 2. Forest plot of complications including dural injury, neurological deficit, blood vessel injury, and infections for ALIF versus TLIF.
IBJN_A_1036838.indd 5
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710
K. Phan & R. J. Mobbs
Study or Subgroup Allograft malposition Hee 2001 Villavicencio 2006 Faundez 2009 Dorward 2013 Subtotal (95% CI)
ALIF Events Total 3 2 0 0
53 43 68 42 206
TLIF Events Total Weight 1 0 3 2
111 28.9% 124 23.5% 65 24.0% 42 23.6% 342 100.0%
Risk Ratio M-H, Random, 95% CI Year 6.28 [0.67, 58.98] 14.20 [0.70, 290.16] 0.14 [0.01, 2.59] 0.20 [0.01, 4.04] 1.35 [0.14, 13.18]
2001 2006 2009 2013
1.57 [0.36, 6.77] 1.24 [0.51, 3.01] 0.96 [0.06, 14.87] 0.18 [0.01, 4.33] 2.20 [0.84, 5.78] 1.46 [0.82, 2.59]
2001 2006 2009 2010 2013
Risk Ratio M-H, Random, 95% CI
5 Total events 6 Heterogeneity: Tau2 = 3.39; Chi2 = 8.09, df = 3 (P = 0.04); I2 = 63% Test for overall effect: Z = 0.26 (P = 0.80) Pedicle malposition
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Hee 2001 Villavicencio 2006 Kim 2009 Kim 2010 Dorward 2013 Subtotal (95% CI )
3 6 1 0 11
53 43 48 86 42 272
4 14 1 1 5
111 15.5% 124 41.6% 46 4.4% 46 3.3% 42 35.3% 369 100.0%
Total events 21 25 Heterogeneity: Tau2 = 0.00; Chi2 = 2.60, df = 4 (P = 0.63); I2 = 0% Test for overall effect: Z = 1.29 (P = 0.20) 0.001 0.1 1 10 1000 Favours ALIF Favours TLIF
Fig. 3. Forest plot for allograft and pedicle malposition for ALIF versus TLIF.
operative duration and blood loss between ALIF and TLIF approaches. However, from the present systematic review, a significant reduction in hospitalization was noted in the TLIF group compared with that in ALIF group. One explanation for this observation may be that the anterior ALIF approach also requires posterior access for pedicle instrumentation, which may translate increased surgical trauma and hospital stay required compared with TLIF, whereas the posterior procedure allows access for both disk removal and instrumentation.22 Radiographic and clinical functional outcomes were reported by only few of the included comparative studies. Previous studies have suggested that ALIF is superior to TLIF in terms of disk height and lumbar lordosis restoration. Results from the present meta-analysis also support this notion, with higher disk height, segmental lordosis, and whole lumbar lordosis noted across studies9,12,14,15 in the ALIF cohorts compared with those in TLIF cohorts. These results suggest that ALIF may be a better approach for restoration of foraminal height, local disk angle, and lumbar lordosis. One justification for the observed trends is the nature of the ALIF procedure, which involves distraction of adjacent vertebral bodies to allow insertion of an interbody graft. This distraction may also result in increased disk height and improve lumbar lordosis.3,23,24 Restoration of these radiographic features is important for improved sagittal balance in these patients. Functional outcomes including ODI and VAS leg/back pain scores were poorly reported from the included studies. Overall, there was no notable difference between ALIF and TLIF approaches in functional scores, suggesting that surgical techniques are effective in back pain and radiculopathy management. These trends require further validation in prospective, adequately powered studies. Complication rates for ALIF and TLIF were mostly comparable except for two exceptions. There was a notable lower
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level of dural injury in the ALIF cohort compared with that in the TLIF cohort. This is most likely due to the nature of the anterior approach and anatomy of the vertebral body and spinal canal. The ALIF approach allows easier access and approach to the disk, which is anterior to the dura and hence limits direct contact between the surgeon and dura. In contrast, the TLIF approach requires retraction of nerve roots and opening the neural foramen on one side to access the disk space.4,13,22 Excess retraction force may translate into increased rates of dural tears or injury compared with the ALIF approach. Additionally, the present meta-analysis demonstrated that ALIF was associated with significantly higher blood vessel injury. This result is not surprising, given that the anterior technique involves exposure, manipulation, and mobilization of the iliac vessels, which increases the risk of bleeding via lacerations and thrombosis.7,8 Given the higher risk of vascular injury during ALIF, vascular surgical support should be readily available during an ALIF operation, should any vascular complications arise. The present systematic review and meta-analysis is limited by several constraints. Firstly, the majority of included studies were retrospective in design, which may introduce selection bias and undermine the validity of the presented results.11 The small sample sizes of included studies also limit the statistical power to distinguish between complication rates of ALIF versus TLIF groups. The heterogeneity of the ALIF and TLIF procedures between centers, as well as differing surgeon-specific technical expertise and experience, also limits the validity of the analyzed results. Specifically, ALIF was performed with posterior instrumentation in some studies, and without instrumentation in two studies.9,13 A subgroup analysis was performed to see whether any differences in outcomes were observed for ALIF with versus without posterior instrumentation; however, the lack of studies and statistical power precluded any meaningful conclusions.
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ALIF versus TLIF: Systematic review 711 Another major limitation is poor reporting of endpoints including radiographic and functional clinical outcomes, which means that definitive comparisons between ALIF and TLIF groups could not be concluded. Outcomes such as adjacent segment degeneration and disease were poorly reported, and should be addressed in future investigations. Prospective, multi-center registry studies of adequate statistical power may provide further evidence to conclusively assess the risks and benefits of ALIF versus TLIF procedures.
8. 9.
10.
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Conclusion In summary, both ALIF and TLIF appeared to be effective fusion techniques with similar fusion rates, operative duration, blood loss, and postoperative VAS and ODI pain scores. ALIF was associated superior disk height, segmental and lumbar lordosis restoration, and longer hospitalization. ALIF was also associated with fewer dural injuries but significantly higher rates of vascular injuries. These trends require further validation in prospective studies with adequate sample size and follow-up.
11.
12.
13.
14.
Acknowledgements None declared.
15.
Funding None. Declaration of interest: The authors report no declarations of interest. The authors alone are responsible for the content and writing of the paper.
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