Retrospective cohort study.
To compare clinical and radiographic outcomes among minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), extreme lateral lumbar interbody fusion (XLIF), and oblique lateral lumbar interbody fusion (OLIF) techniques.
To date, there are many reports comparing outcomes between MIS-TLIF and XLIF, MIS-TLIF and OLIF, or XLIF and OLIF procedures. However, there are no previous studies comparing clinical and radiographic outcomes among all these three techniques.
Data from patients who underwent minimally invasive (MI) fusion surgery for lumbar degenerative diseases at L4–L5 level was analyzed. Thirty patients each from MIS-TLIF, XLIF, and OLIF groups were recruited for propensity score matching. Visual Analog Scale (VAS) of the back and legs and Oswestry Disability Index (ODI) were evaluated preoperatively and at 1, 3, and 6 months and 1 year postoperatively. Radiographic outcomes were also compared. The fusion rate was evaluated at 1 year after surgeries.
The clinical outcomes were significantly improved in all groups. The disk height was significantly restored in all groups postoperatively, which was significantly more improved in XLIF and OLIF than MIS-TLIF group (
MIS-TLIF, XLIF, and OLIF facilitated safe and effective MI procedures for treating lumbar degenerative diseases. XLIF and OLIF can achieve clinical outcomes equivalent to MIS-TLIF by indirect decompression. XLIF and OLIF showed less blood loss, shorter hospital stays, and better disk and foraminal height restorations. In single-level L4–5, the restoration of sagittal alignment was similar between these three techniques.
Lumbar interbody fusion has been popularized for surgical treatment in patients with chronic back pain with or without radiculopathy [
In this study, we focused on three common MI techniques: minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), extreme lateral lumbar interbody fusion (XLIF), and oblique lateral lumbar interbody fusion (OLIF). The MIS-TLIF delivers direct decompression of spinal canal via unilateral access to the spinal canal and intervertebral foraminal space. The XLIF involves accessing the targeted disk space via a lateral retroperitoneal, transpsoas corridor, and provides indirect decompression of spinal canal. Lastly, OLIF also provides indirect decompression effect but involves accessing the disk space via a corridor between great vessels and psoas muscle (
To date, there are many reports comparing clinical or radiographic outcomes among these MI lumbar fusion surgeries. Some of these studies compared the outcomes between MIS-TLIF and XLIF [
This retrospective study comparatively analyzed patients’ data collected from July 2016 to July 2019 from a single institution. This study was approved by the Institutional Review Board (IRB) of the Faculty of Medicine, Chulalongkorn University (IRB no., 478/62). Informed consent was obtained from all individual participants included in the study. All patients with lumbar degenerative diseases were treated by senior spinal surgeons who have performed more than 100 cases of each procedure.
The sample size of this study was calculated by using the formula: n/group=2(Zα/2+Zβ)2σ2/(μ1−μ2)2.
We applied type I error α=0.05, type II error β=0.20, and power of test=80% in this formula. The other variables were applied from a study of Lin et al. [
Altogether, 363 patients who underwent the operation were analyzed (MIS-TLIF=135, XLIF=126, and OLIF=102 cases). We used propensity score comparison for three-way matching, with 30 patients in each group, using the inverse probability of treatment weighting statistics of preoperative demographic data and preoperative clinical and radiographic outcomes for preventing selection bias [
This procedure was performed by one author (W.S.) of this study. The patient was operated in prone position. The procedures included hemi-laminectomy, medial facetectomy, and ligamentum flavum removal on the approach side, discectomy, and endplate preparation. Then, the interbody cage (CAPSTONE; Medtronic, Minneapolis, MN, USA) filled with an autogenous local bone graft was inserted into the prepared disk space. Finally, supplement posterior instrumentation was placed percutaneously in standard fashion.
The XLIF procedure was performed by the author (W.Y.). Neurophysiological monitoring was applied to all patients to avoid lumbar plexus injuries during psoas muscle splitting. Patient was positioned in right lateral decubitus with the iliac crest placed on table break. The surgical approach was performed step by step to access the retroperitoneal space. The psoas muscle was identified and split. Then, a self-retaining retractor was applied. Discectomy and endplate preparation were performed. The proper-sized cage (Cohere; NuVasive Inc., San Diego, CA, USA) filled with demineralized bone matrix (DBM, ATTRAX; NuVasive Inc., San Diego, CA, USA) was inserted into the operated disk space. Lastly, the lateral plate was then fixed to the L4 and L5 vertebral bodies. The patient was subsequently turned into prone position after completion of the lateral procedure. Posterior instrumentation was performed percutaneously in this position.
This technique was performed by the author (W.L.). The patient was placed in the right lateral decubitus position. The surgical approach was performed to reach the retroperitoneal corridor between the psoas muscle and great vessels. The self-retaining retractor was placed upon the operated disk level after sequential dilators were applied. Thorough discectomy and endplate preparation were performed using the orthogonal maneuver. The appropriate-sized cage (CLYDESDALE; Medtronic) filled with DBM (GRAFTON; Medtronic) was inserted orthogonally into the operated disk space. Percutaneous posterior instrumentation was placed in prone position after completion of the lateral procedure.
Functional outcomes regarding Visual Analog Scale (VAS) score and the Oswestry Disability Index (ODI) for low back pain were evaluated preoperatively and at 1, 3, and 6 months and 1 year postoperatively.
All patients obtained plain radiographs preoperatively and postoperatively. The anterior disk height (ADH), posterior disk height (PDH), foraminal height (FH), segmental sagittal angle (SSA), and lumbar lordotic angle (LLA) were measured (
Magnetic resonance images (MRI) with a 1.5-Tesla unit (Aera, Siemens Medical Solutions; Erlangen, Bavaria, Germany) was obtained preoperatively and at 3 months postoperatively in all patients. The axial canal area (ACA) and axial canal diameter (ACD) were measured (
The statistical analyses were performed by IBM SPSS ver. 22.0 (IBM Corp., Armonk, NY, USA). The change between the preoperative and postoperative clinical outcomes in VAS (leg), VAS (back), and ODI was analyzed by using repeated analysis of variance (ANOVA) and subgroup analysis by the Bonferroni test. The change between preoperative and postoperative radiographic values in ADH, PDH, FH, SSA, LLA, ACA, and ACD was analyzed by using ANOVA and subgroup analysis by the Bonferroni test. Intraobserver and interobserver reliabilities were evaluated using the Cronbach α. A
A total of 90 patients were included in this study. Thirty patients per group underwent MIS-TLIF, XLIF, and OLIF. Demographic data was shown in
The perioperative comparison between all groups was shown in
Regarding the perioperative time, there was no statistical significance between each procedure. There was a significant difference regarding length of hospital stays (
Concerning to complications, one patient in OLIF group developed deep vein thrombosis, and two patients had transient thigh pain in XLIF group.
There was no significant difference between baseline preoperative clinical parameters (VAS scores of back and leg, ODI score) among MIS-TLIF, XLIF, and OLIF groups. The VAS score of back of all techniques showed significant improvement in any postoperative time point (1, 3, and 6 months and 1 year) compared with preoperative score of each procedure. There was no statistically significant difference between these groups (
There was no significant difference in baseline preoperative radiographic parameters among MIS-TLIF, XLIF, and OLIF. The ADH, PDH, FH, FA, SSA, LLA, ACA, and ACD were significantly improved postoperatively after all the procedures (
The ADH was significantly restored in all three groups, where MIS-TLIF, XLIF, and OLIF approaches yielded increases of 18.35%, 51.10%, and 45.61%, respectively. Subgroup analysis showed that the ADH significantly increased in XLIF and OLIF more than in MIS-TLIF (
The PDH was also significantly restored in all groups, where MIS-TLIF, XLIF, and OLIF yielded increases of 19.21%, 50.68%, and 42.45%, respectively. Subgroup analysis showed that the PDH significantly increased in XLIF and OLIF more than in MIS-TLIF (
The FH was significantly improved in all groups. Based on the subgroup analysis, XLIF significantly restored FH compared to MIS-TLIF (
Based on the subgroup analysis, there were no significant differences regarding the correction of SSA among all groups. Similarly, there were no significant differences regarding the restoration of LLA among all techniques based on subgroup analysis.
We found that ACA was significantly increased from preoperative to postoperative time point in MIS-TLIF by 211%, XLIF by 78.79%, and OLIF by 82.93%. Based on the subgroup analysis, the canal area was significantly increased more in MIS-TLIF than in XLIF (
The ACD was significantly restored from preoperative to postoperative period in MIS-TLIF, XLIF, and OLIF groups. Subgroup analysis demonstrated that the diameter significantly increased more in MIS-TLIF group than in XLIF and OLIF groups.
The fusion rate was not significantly different at 1-year evaluation. The MIS-TLIF group demonstrated fusion in 28/30 (93.3%), and XLIF and OLIF groups resulted in fusion in 29/30 (96.7%).
There was no statistically significant difference in subsidence rate at 1-year follow-up. Cage subsidence occurred in 43.33% (13/30), 43.33% (13/30), and 50% (15/30) of patients in MIS-TLIF, XLIF, and OLIF groups, respectively.
MI lumbar interbody fusion has gained popularity in the treatment of degenerative lumbar spine diseases due to favorable results with less collateral damage to paraspinal muscles and ligaments. MIS-TLIF, XLIF, and OLIF are currently considered as promising treatment options. As with open TLIF surgery, the MIS-TLIF can directly decompress neural element with reported better short-term outcomes following the surgery including less bleeding, postoperative pain, hospitalization, and complications [
Regarding clinical outcomes, we discovered that all three groups were significantly improved in the outcomes at all studied time points compared with preoperative period, as evidenced by better VAS score of back and leg and ODI in this study. These findings were consistent with many previous reports [
The radiographic outcomes regarding ADH, PDH, FH, ACA, and ACD were significantly improved in all the three techniques. The restorations of ADH, PDH, and FH were significantly more favorable in both OLIF and XLIF than in MIS-TLIF in this study, which were in accordance with previous studies [
In contrast, the ACA and ACD were significantly improved better in MIS-TLIF than the other two groups. This is due to the effect of direct decompression from MIS-TLIF, which directly removed ipsilateral posterior bony elements and ligamentum flavum to decompress and expand the spinal canal. In contract with MIS-TLIF, XLIF, and OLIF procedures achieve indirect decompression of the spinal canal by implantation of interbody cage, which resulted in unbuckling of ligamentum flavum, stretching of ligaments, and increasing disc height. These results were similar to a randomized controlled trial reported by Isaacs et al. [
Our study demonstrated an improvement of overall lumbar lordosis postoperatively in all groups. Nevertheless, there was no statistically significant difference in LLA and SSA among all groups, which was contrary to a previous study [
The transient anterior thigh pain following XLIF procedure in this study (6.6%) was lower than previously reported in the systematic review by Gammal et al. [
This study has some limitations. This study was a retrospective, nonrandomized single-center study. We did not include preoperative MRI data for the propensity score matching that might cause selection bias. Moreover, this study included only L4–5 lumbar fusion. The clinical results, radiographic outcomes, and complications may differ when other spinal levels or multilevel were operated. Further studies with prospective, longer follow-up periods, and larger patient cohorts are warranted.
MIS-TLIF, XLIF, and OLIF are safe and effective MI procedures for treating lumbar degenerative diseases. XLIF and OLIF can achieve clinical outcomes equivalent to MIS-TLIF. XLIF and OLIF showed less blood loss, shorter hospital stays, and superior improvement in restoring DH and FH than MIS-TLIF. In single-level L4–5, the restoration of sagittal alignment was similar between these three techniques.
The authors thank Thanachaporn Kittipibul, MD., Mrs. Dollapas Punpanich and Chulalongkorn University Spine Team for their support of this study.
No potential conflict of interest relevant to this article was reported.
Wicharn Yingsakmongkol: conceptualization, resources; Khanathip Jitpakdee: data collection; Panapol Varakornpipat: data collection, writing (original draft); Chitapoom Choentrakool: data analysis; Teerachat Tanasansomboon: writing (review and editing); Worawat Limthongkul: supervision, resources; Weerasak Singhatanadgige: methodology, resources; Vit Kotheeranurak: writing (review and editing), supervision.
Schematic drawing of different techniques of minimally invasive lumbar interbody fusion. MIS-TLIF, minimally invasive transforaminal lumbar interbody fusion; XLIF, extreme lateral lumbar interbody fusion; OLIF, oblique lateral lumbar interbody fusion.
Anterior disc height (ADH), posterior disc height (PDH), foraminal height (FH), and segmental sagittal angle (SSA) were measured on lateral standing plain radiographs preoperatively
Axial canal area (ACA) and axial canal diameter (ACD) were measured on axial cut T2-weighted MRI preoperatively
Demographic data
Characteristic | MIS-TLIF (n=30) | XLIF (n=30) | OLIF (n=30) | |
---|---|---|---|---|
Age (yr) | 67.1±5.29 | 63.53±7 | 63±9.7 | 0.079 |
Gender | ||||
Female | 24 (80.0) | 22 (73.3) | 22 (73.3) | 0.786 |
Male | 6 (20.0) | 8 (26.7) | 8 (26.7) | 0.786 |
Diabetes mellitus | 8 (26.7) | 4 (13.3) | 7 (23.3) | 0.420 |
Hypertension | 22 (73.3) | 16 (53.3) | 24 (80.0) | 0.067 |
Dyslipidemia | 17 (56.7) | 10 (33.3) | 13 (43.3) | 0.189 |
Diagnosis | ||||
Spinal stenosis | 9 (30.0) | 8 (26.7) | 9 (30.0) | 0.947 |
Spondylolisthesis | 21 (7.0) | 22 (73.3) | 21 (70.0) | 0.947 |
Values are presented as mean±standard deviation or number (%).
MIS-TLIF, minimally invasive transforaminal lumbar interbody fusion; XLIF, extreme lateral lumbar interbody fusion; OLIF, oblique lateral lumbar interbody fusion.
Perioperative data
Variable | MIS-TLIF (n=30) | XLIF (n=30) | OLIF (n=30) | Multiple comparisons by Bonferroni test | |||
---|---|---|---|---|---|---|---|
M vs. X | M vs. O | X vs. O | |||||
Duration of hospital stay (day) | 4.33±0.61 | 3.6±0.62 | 3.7±0.53 | <0.001 |
<0.001 |
<0.001 |
1 |
Operation | |||||||
Operative time (hr) | 2.82±0.47 | 2.4±0.81 | 2.53±0.51 | 0.03 | 0.029 |
0.218 | 1 |
Estimated blood loss (mL) | 200.33±59.22 | 49.17±32.91 | 48.67±33.4 | <0.001 |
<0.001 |
<0.001 |
1 |
Complication | |||||||
No | 30 (100.0) | 28 (93.3) | 27 (90.0) | 0.384 | 0.150 | 0.206 | 0.601 |
Deep vein thrombosis | 0 | 0 | 1 (3.3) | ||||
Thigh pain | 0 | 2 (6.7) | 0 |
Values are presented as mean±standard deviation or number (%).
MIS-TLIF, minimally invasive transforaminal lumbar interbody fusion; XLIF, extreme lateral lumbar interbody fusion; OLIF, oblique lateral lumbar interbody fusion; M vs. X, MIS-TLIF vs. XLIF; M vs. O, MIS-TLIF vs. OLIF; X vs. O, XLIF vs. OLIF.
By analysis of variance test.
Statistically significant.
Clinical outcomes
Variable | MIS TLIF (n=30) | XLIF (n=30) | OLIF (n=30) | Multiple comparisons by Bonferroni | |||
---|---|---|---|---|---|---|---|
M vs. X | M vs. O | X vs. O | |||||
VAS (back) | |||||||
Preoperative | 8.2±1.42 | 7.93±1.28 | 8.4±1.5 | 0.438 | 1 | 1 | 0.606 |
1 mo | 1.63±2.24 | 1.6±1.61 | 1.8±2.33 | 0.924 | 1 | 1 | 1 |
3 mo | 0.67±1.65 | 0.77±1.43 | 0.83±1.29 | 0.906 | 1 | 1 | 1 |
6 mo | 0.3±1.06 | 0.4±1.1 | 0.4±1.16 | 0.922 | 1 | 1 | 1 |
1 yr | 0.1±0.55 | 0.47±1.11 | 0.1±0.55 | 0.116 | 0.216 | 1 | 0.216 |
Difference of 1 mo | −6.57 (−7.6 to −5.54) |
−6.33 (−6.9 to −5.77) |
−6.6 (−7.56 to −5.64) |
0.892 | 1 | 1 | 1 |
Difference of 3 mo | −7.53 (−8.25 to −6.82) |
−7.17 (−7.87 to −6.46) |
−7.57 (−8.22 to −6.91) |
0.652 | 1 | 1 | 1 |
Difference of 6 mo | −7.9 (−8.53 to −7.27) |
−7.53 (−8.16 to −6.91) |
−8 (−8.63 to −7.37) |
0.530 | 1 | 1 | 0.857 |
Difference of 1 yr | −8.1 (−8.72 to −7.48) |
−7.47 (−8.08 to −6.85) |
−8.3 (−8.86 to −7.74) |
0.117 | 0.391 | 1 | 0.143 |
VAS (leg) | |||||||
Preoperative | 7.87±2.1 | 7.7±0.99 | 7.7±1.76 | 0.907 | 1 | 1 | 1 |
1 mo | 1±1.34 | 1.37±2.33 | 1.63±2.22 | 0.475 | 1 | 0.678 | 1 |
3 mo | 0.63±1.38 | 0.77±1.83 | 0.3±1.15 | 0.457 | 1 | 1 | 0.676 |
6 mo | 0.57±1.43 | 0.5±1.59 | 0.2±0.66 | 0.508 | 1 | 0.826 | 1 |
1 yr | 0.2±0.81 | 0.47±1.48 | 0.03±0.18 | 0.229 | 0.882 | 1 | 0.269 |
Difference of 1 mo | −6.87 (−7.85 to −5.89) |
−6.33 (−7.22 to −5.44) |
−6.07 (−7.18 to −4.95) |
0.502 | 1 | 0.751 | 1 |
Difference of 3 mo | −7.23 (−8.22 to −6.24) |
−6.93 (−7.61 to −6.26) |
−7.4 (−8.21 to −6.59) |
0.716 | 1 | 1 | 1 |
Difference of 6 mo | −7.3 (−8.3 to −6.3) |
−7.2 (−7.87 to −6.53) |
−7.5 (−8.21 to −6.79) |
0.861 | 1 | 1 | 1 |
Difference of 1 yr | −7.67 (−8.53 to −6.8) |
−7.23 (−7.9 to −6.57) |
−7.67 (−8.33 to −7.01) |
0.619 | 1 | 1 | 1 |
ODI | |||||||
Preoperative | 53.4±16.56 | 52.68±18.85 | 52.98±17.88 | 0.988 | 1 | 1 | 1 |
1 mo | 15.16±18.21 | 21.74±20.98 | 11.49±14.44 | 0.090 | 0.486 | 1 | 0.092 |
3 mo | 6.93±15.31 | 12.73±16.75 | 7.35±15.67 | 0.296 | 0.486 | 1 | 0.584 |
6 mo | 2.22±7.9 | 5.47±10.87 | 3.06±7.47 | 0.342 | 0.478 | 1 | 0.882 |
1 yr | 0±0 | 3.13±8.24 | 0.22±1.22 | 0.023 |
0.040 |
1 | 0.063 |
Difference of 1 mo | −38.24 (−48.18 to −28.31) |
−30.94 (−42.24 to −19.64) |
−41.49 (−50.06 to −32.92) |
0.300 | 0.881 | 1 | 0.392 |
Difference of 3 mo | −46.47 (−55.48 to −37.47) |
−39.95 (−50.56 to −29.35) |
−45.63 (−54.49 to −36.76) |
0.562 | 0.975 | 1 | 1 |
Difference of 6 mo | −51.18 (−58.3 to −44.06) |
−47.21 (−55.9 to −38.51) |
−49.92 (−56.97 to −42.88) |
0.746 | 1 | 1 | 1 |
Difference of 1 yr | −53.4 (−59.59 to −47.22) |
−49.65 (−57.64 to −41.67) |
−52.76 (−59.66 to −45.85) |
0.715 | 1 | 1 | 1 |
Values are presented as mean±standard deviation or difference (95% confidence interval).
MIS-TLIF, minimally invasive transforaminal lumbar interbody fusion; XLIF, extreme lateral lumbar interbody fusion; OLIF, oblique lateral lumbar interbody fusion; M vs. X, MIS-TLIF vs. XLIF; M vs. O, MIS-TLIF vs. OLIF; X vs. O, XLIF vs. OLIF; VAS, Visual Analog Scale; ODI, Oswestry Disability Index.
By analysis of variance test.
Statistically significant.
Radiographic outcomes
Variable | MIS TLIF (n=30) | XLIF (n=30) | OLIF (n=30) | Multiple comparisons by Bonferroni test | |||
---|---|---|---|---|---|---|---|
M vs. X | M vs. O | X vs. O | |||||
Anterior disc height (mm) | |||||||
Preop | 8.36±2.83 | 7.37±2.22 | 9.11±3.17 | 0.056 | 0.510 | 0.893 | 0.051 |
Postop | 10.24±2.4 | 15.05±2.33 | 14.6±1.96 | <0.001 |
<0.001 |
<0.001 |
1 |
Mean difference (95% CI) | 1.88 (1.08 to 2.68) |
7.68 (6.89 to 8.47) |
5.49 (4.41 to 6.57) |
<0.001 |
<0.001 |
<0.001 |
0.002 |
%Change postop | 28.3% | 115% | 79.8% | <0.001 |
<0.001 |
<0.001 |
0.022 |
Posterior disc height (mm) | |||||||
Preop | 6.98±1.45 | 6.44±1.21 | 7.32±2.11 | 0.119 | 0.616 | 1 | 0.124 |
Postop | 8.64±1.48 | 13.06±2.48 | 12.72±2.19 | <0.001 |
<0.001 |
<0.001 |
1 |
Mean difference (95% CI) | 1.67 (1.3 to 2.03) |
6.62 (5.73 to 7.5) |
5.4 (4.31 to 6.49) |
<0.001 |
<0.001 |
<0.001 |
0.114 |
%Change postop | 26% | 107% | 87.1% | <0.001 |
<0.001 |
<0.001 |
0.227 |
Foraminal height (mm) | |||||||
Preop | 15.35±1.77 | 14.7±2.59 | 14.33±2.49 | 0.229 | 0.852 | 0.272 | 1 |
Postop | 16.95±2.12 | 19.03±2.46 | 20.32±3.25 | <0.001 |
0.009 | <0.001 |
0.191 |
Mean difference (95% CI) | 1.6 (0.67 to 2.53) |
4.33 (3.32 to 5.34) |
5.99 (4.91 to 7.08) |
<0.001 |
0.001 | <0.001 |
0.058 |
%Change postop | 11.5% | 31.9% | 44.1% | <0.001 |
0.001 |
<0.001 |
0.1 |
Segmental sagittal angle (°) | |||||||
Preop | 10.6±5.93 | 8.7±5.4 | 11.73±6.67 | 0.160 | 0.396 | 1 | 0.227 |
Postop | 12.8±6 | 10.23±6.3 | 13.27±7.25 | 0.149 | 0.675 | 1 | 0.163 |
Mean difference (95% CI) | 2.2 (−0.27 to 4.13) |
1.53 (−0.28 to 3.34) | 1.53 (−0.46 to 3.53) | 0.844 | 1 | 1 | 1 |
%Change postop | 12.8% | 2.2% | 9.1% | 0.592 | 1 | 0.955 | 1 |
Lumbar lordotic angle (°) | |||||||
Preop | 30.63±13.01 | 26.2±12.8 | 25.97±13.69 | 0.307 | 0.587 | 0.521 | 1 |
Postop | 34.5±10.07 | 27.13±11.92 | 27.77±11.96 | 0.024 |
0.041 |
0.072 | 1 |
Mean difference (95% CI) | 3.87 (0.86 to 6.88) |
0.93 (−1.21 to 3.08) | 1.8 (−0.44 to 4.04) | 0.223 | 0.278 | 0.703 | 1 |
%Change postop | 24.2% | 29.2% | 47.7% | 0.693 | 1 | 1 | 1 |
Axial canal area (mm2) | |||||||
Preop | 46.79±27.94 | 76.85±44.33 | 66.83±32.55 | 0.005 |
0.005 |
0.096 | 0.836 |
Postop | 145.52±41.46 | 137.4±48.22 | 122.24±46.3 | 0.137 | 1 | 0.151 | 0.599 |
Mean difference (95% CI) | 98.73 (84.45 to 113) |
60.55 (51.55 to 69.54) |
55.42 (43.31 to 67.52) |
<0.001 |
<0.001 |
<0.001 |
1 |
%Change postop | 390.4% | 113.6% | 95.5% | <0.001 |
<0.001 |
<0.001 |
1 |
Axial canal diameter (mm) | |||||||
Preop | 6.99±2.57 | 8.4±2.53 | 8.42±2.73 | 0.057 | 0.117 | 0.112 | 1 |
Postop | 11.78±2.08 | 11.67±2.36 | 12.05±2.96 | 0.838 | 1 | 1 | 1 |
Mean difference (95% CI) | 4.79 (3.84 to 5.75) |
3.27 (2.7 to 3.84) |
3.63 (3.04 to 4.22) |
0.009 |
0.010 |
0.05 |
1 |
%Change postop | 98.1% | 44.5% | 48.3% | 0.003 |
0.007 |
0.013 |
1 |
Values are presented as mean±standard deviation or difference (95% confidence interval), unless otherwise stated.
MIS-TLIF, minimally invasive transforaminal lumbar interbody fusion; XLIF, extreme lateral lumbar interbody fusion; OLIF, oblique lateral lumbar interbody fusion; M vs. X, MIS-TLIF vs. XLIF; M vs. O, MIS-TLIF vs. OLIF; X vs. O, XLIF vs. OLIF; Preop, preoperative; Postop, postoperative; CI, confidence interval.
By analysis of variance test.
Statistically significant.