Effectiveness and safety of unilateral pedicle screw fixation in transforaminal lumbar interbody fusion (TLIF): a systematic review and meta-analysis

Biomechanical Comparison of Unilateral and Bilateral Pedicle Screw Fixation after Multilevel Lumbar Lateral Interbody Fusion

STUDY DESIGN

Human Cadaveric Biomechanical Study.

OBJECTIVES

Lumbar Lateral Interbody Fusion (LLIF) utilizing a wide cage has been reported as having favorable biomechanical characteristics. We examine the biomechanical stability of unilateral pedicle screw and rod fixation after multilevel LLIF utilizing 26 mm wide cages compared to bilateral fixation.

METHODS

Eight human cadaveric specimens of L1-L5 were included. Specimens were attached to a universal testing machine (MTS 30/G). Three-dimensional specimen range of motion (ROM) was recorded using an optical motion-tracking device. Specimens were tested in 3 conditions: 1) intact, 2) L1-L5 LLIF (4 levels) with unilateral rod, 3) L1-L5 LLIF with bilateral rods.

RESULTS

From the intact condition, LLIF with unilateral rod decreased flexion-extension by 77%, lateral bending by 53%, and axial rotation by 26%. In LLIF with bilateral rods, flexion-extension decreased by 83%, lateral bending by 64%, and axial rotation by 34%. Comparing unilateral and bilateral fixation, LLIF with bilateral rods reduced ROM by a further 23% in flexion-extension, 25% in lateral bending, and 11% in axial rotation. The difference was statistically significant in flexion-extension and lateral bending (P < .005).

CONCLUSIONS

Considerable decreases in ROM were observed after multilevel (4-level) LLIF utilizing 26 mm cages supplemented with both unilateral and bilateral pedicle screws and rods. The addition of bilateral fixation provides a 10-25% additional decrease in ROM. These results can inform surgeons of the incremental biomechanical benefit when considering unilateral or bilateral posterior fixation after multilevel LLIF.

Long-term comparison of anterior (ALIF) versus transforaminal (TLIF) lumbar interbody fusion: a propensity score-matched register-based study

PURPOSE

Anterior (ALIF) and transforaminal (TLIF) lumbar interbody fusion have shown similar clinical outcomes at short- and medium-term follow-ups. Possible advantages of ALIF in the long run could be better disc height and lumbar lordosis and reduced risk of adjacent segment disease. We aimed to study if ALIF could be associated with superior clinical outcomes than TLIF at long-term follow-up.

METHODS

We analysed 535 patients treated with ALIF or TLIF of the L5-S1 spinal segment between 2007 and 2017 who completed long-term follow-up in a national spine registry database (NORspine). We defined treatment success after surgery as at least 30% improvement in Oswestry Disability Index (ODI) at long-term follow-up. Patients treated with ALIF and TLIF and who responded at long term were balanced by propensity score matching. The proportions of successfully treated patients within each group were compared by numbers and percentages with corresponding relative risk.

RESULTS

The mean (95%CI) age of the total study population was 50 (49-51) years, and 264 (49%) were females. The mean (95%CI) preoperative ODI score was 40 (39-42), and 174 (33%) had previous spine surgery. Propensity score matching left 120 patients in each treatment group. At a median (95%CI) of 92 (88-97) months after surgery, we found no difference in proportions successfully treated patients with ALIF versus TLIF (68 (58%) versus 77 (65%), RR (95%CI) = 0.88 (0.72 to1.08); p = 0.237).

CONCLUSIONS

This propensity score-matched national spine register study of patients treated with ALIF versus TLIF of the lumbosacral junction found no differences in proportions of successfully treated patients at long-term follow-up.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Minimally invasive transforaminal lumbar interbody fusion with unilateral pedicle screw fixation (UNILF): outcomes at 7 years

PURPOSE

To assess clinical, functional and radiographical results of one-level minimally invasive transforaminal interbody fusion with unilateral pedicle screw fixation (UNILIF) in the treatment of stable lumbar degenerative diseases with a minimum of 5 years of follow-up.

MATERIAL AND METHOD

From January 2012 to December 2016, clinical and radiological data of patients with degenerative lumbar disease managed by UNILIF were prospectively collected. Patients with a follow-up that ended before 5 years were excluded. SF-12, Oswestry disability index (ODI) and visual analog scale (VAS) were collected preoperatively, at 2 years and at the last follow-up. A full-spine standing radiograph was performed at each follow-up appointment.

RESULTS

Mean operative time was 74.7 (± 19) minutes, mean blood loss was 131.1 (± 207) ml and mean follow-up was 7.5 (± 1.7) years. All functional scores and VAS were significantly improved between the preoperative and the 2 years postoperative. Between the 2 years postoperative and the last follow-up ODI and VAS continued to significantly improved. Fusion rate was 98.6% on radiographic analysis at follow-up.

CONCLUSION

UNILIF method is a safe and effective surgical strategy. It provides a durable improvement in functional score over 7 years of follow-up with a stable radiological correction over time.

A Comparison of Radiographic Alignment between Bilateral and Unilateral Interbody Cages in Patients Undergoing Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

Retrospective cohort study.

PURPOSE

To compare radiographic outcomes between unilateral and bilateral cage placement in transforaminal lumbar interbody fusions (TLIF) and to determine if the rate of fusion at the 1-year postoperative point was different in patients who received bilateral versus unilateral cages.

OVERVIEW OF LITERATURE

There is no clear evidence to dictate whether bilateral or unilateral cages promote superior radiographic or surgical outcomes in TLIF.

METHODS

Patients >18 years old who underwent primary one- or two-level TLIFs at our institution were identified and propensitymatched in a 3:1 fashion (unilateral:bilateral). Patient demographics, surgical characteristics, and radiographic outcomes, including vertebral endplate obliquity, segmental lordosis, subsidence, and fusion status, were compared between groups.

RESULTS

Of the 184 patients included, 46 received bilateral cages. Bilateral cage placement was associated with greater subsidence (1.06±1.25 mm vs. 0.59±1.16 mm, p=0.028) and enhanced restoration of segmental lordosis (5.74°±14.1° vs. -1.57°±10.9°, p=0.002) at the 1-year postoperative point, while unilateral cage placement was associated with an increased correction of endplate obliquity (-2.02°±4.42° vs. 0.24°±2.81°, p<0.001). Bilateral cage placement was significantly associated with radiographic fusion on bivariate analysis (89.1% vs. 70.3%, p=0.018) and significantly predicted radiographic fusion on multivariable regression analysis (estimate, 1.35; odds ratio, 3.87; 95% confidence interval, 1.51-12.05; p=0.010).

CONCLUSIONS

Bilateral interbody cage placement in TLIF procedures was associated with restoration of lumbar lordosis and increased fusion rates. However, endplate obliquity correction was significantly greater for patients who received a unilateral cage.

Is unilateral pedicle screw fixation as effective as bilateral pedicle screw fixation in transforaminal lumbar interbody fusion: a meta-analysis of randomized controlled trials

PURPOSE

This meta-analysis aimed to investigate whether unilateral pedicle screw fixation (UPSF) is comparable to bilateral pedicle screw fixation (BPSF) in transforaminal lumbar interbody fusion (TLIF) for lumbar degenerative diseases.

METHODS

Up to September 2022, established electronic literature databases including PubMed, Web of Science, EMBASE, and the Cochrane Library were systematically searched. Randomized controlled trials (RCTs) published in English that compared the efficacy of UPSF versus BPSF in TLIF were included. The methodological quality was evaluated, relevant data was extracted, and suitable meta-analysis was carried out. Data of fusion rate, complications, cage migration, visual analog scale (VAS), and Oswestry Disability Index (ODI), total blood loss (TBL), operation time, and hospital stay were extracted and analyzed. Pooled mean differences and risk ratio (RR) along with 95% confidence intervals (95% CI) were calculated for the results.

RESULTS

Ten RCTs including 614 patients (UPSF = 294, BPSF = 320) were included in our meta-analysis. There were no significant differences in terms of fusion rate, VAS (VAS-BP and VAS-LP), ODI, complications, or hospital stay between UPSF and BPSF groups (P > 0.05, respectively). The UPSF group clearly had the advantage of less blood loss (SMD = -2.99, 95% CI [-4.54, -1.45], P = 0.0001) and operation time (SMD = -2.05, 95% CI [-3.10, -1.00], P = 0.0001). However, UPSF increased cage migration more than BPSF (10.7% vs 4.8%, RR = 2.23, 95% CI [1.07, 4.65],  P = 0.03).

CONCLUSION

According to the findings of this meta-analysis, UPSF is just as effective as BPSF in TLIF and may reduce blood loss and operation time. Nevertheless, UPSF may result in more cage migration than BPSF.

A biomechanical comparison of posterior fixation approaches in lumbar fusion using computed tomography based lumbosacral spine modelling

Extreme lateral interbody fusion (XLIF) may be performed with a standalone interbody cage, or with the addition of unilateral or bilateral pedicle screws; however, decisions regarding supplemental fixation are predominantly based on clinical indicators. This study examines the impact of posterior supplemental fixation on facet micromotions, cage loads and load-patterns at adjacent levels in a L4-L5 XLIF at early and late fusion stages. CT data from an asymptomatic subject were segmented into anatomical regions and digitally stitched into a surface mesh of the lumbosacral spine (L1-S1). The interbody cage and posterior instrumentation (unilateral and bilateral) were inserted at L4-L5. The volumetric mesh was imported into finite element software for pre-processing, running nonlinear static solves and post-processing. Loads and micromotions at the index-level facets reduced commensurately with the extent of posterior fixation accompanying the XLIF, while load-pattern changes observed at adjacent facets may be anatomically dependent. In flexion at partial fusion, compressive stress on the cage reduced by 54% and 72% in unilateral and bilateral models respectively; in extension the reductions were 58% and 75% compared to standalone XLIF. A similar pattern was observed at full fusion. Unilateral fixation provided similar stability compared to bilateral, however there was a reduction in cage stress-risers with the bilateral instrumentation. No changes were found at adjacent discs. Posterior supplemental fixation alters biomechanics at the index and adjacent levels in a manner that warrants consideration alongside clinical information. Unilateral instrumentation is a more efficient option where the stability requirements and subsidence risk are not excessive.

A meta-analysis of risk factors for cage migration after lumbar fusion surgery

Objective

Cage migration is a rare complication after lumbar fusion surgery, and it is also the cause of lumbar revision surgery. Previous studies have reported that many influencing factors can increase the incidence of cage migration. However, there still remains controversial. The current study was conducted to investigate the risk factors influencing incidence of cage migration.

Methods

A systematic database search of PubMed, Embase, Web of Science, Cochrane Library and Clinical Trials was performed for relevant articles published until July 2022. According to the inclusion and exclusion criteria, two evaluators independently conducted literature screening, data extraction and quality evaluation of the obtained literature. The Newcastle-Ottawa Scale (NOS) score was used for quality evaluation, and meta-analysis was performed by STATA 16.0 software.

Results

A total of 2126 relevant articles were initially identified, and 7 articles were finally included in this study for data extraction and meta-analysis. The results of meta-analysis showed that the bony endplate injury, pear-shaped disc, and screw loosening are significantly correlated with cage migration. The OR values (95%CI) of the three factors were 7.170 (3.015, 17.051), 8.056 (4.050, 16.023), and 12.840 (3.570, 46.177) respectively.

Conclusion

Bony endplate injury, pear-shaped disc, and screw loosening are the current risk factors for cage migration postoperatively.

Successful outcomes of unilateral vs bilateral pedicle screw fixation for lumbar interbody fusion: A meta-analysis with evidence grading

BACKGROUND

Whether it’s better to adopt unilateral pedicle screw (UPS) fixation or to use bilateral pedicle screw (BPS) one for lumbar degenerative diseases is still controversially undetermined.

AIM

To make a comparison between UPS and BPS fixation as to how they work efficaciously and safely in patients suffering from lumbar degenerative diseases.

METHODS

We have searched a lot in the databases through 2020 with index terms such as “unilateral pedicle screw fixation” and “bilateral pedicle screw fixation.” Only randomized controlled trials and some prospective cohort studies could be found, yielding 15 studies. The intervention was unilateral pedicle screw fixation; Primarily We’ve got outcomes of complications and fusion rates. Secondarily, we’ve achieved outcomes regarding total blood loss, operative time, as well as length of stay. Softwares were installed and utilized for subgroup analysis, analyzing forest plots, sensitivity, heterogeneity, forest plots, publication bias, and risk of bias.

RESULTS

Fifteen previous cases of study including 992 participants have been involved in our meta-analysis. UPS had slightly lower effects on fusion rate [relative risk (RR) = 0.949, 95%CI: 0.910 to 0.990, P = 0.015], which contributed mostly to this meta-analysis, and similar complication rates (RR = 1.140, 95%CI: 0.792 to 1.640, P = 0.481), Δ visual analog scale [standard mean difference (SMD) = 0.178, 95%CI: -0.021 to 0.378, P = 0.080], and Δ Oswestry disability index (SMD = -0.254, 95%CI: -0.820 to 0.329, P = 0.402). In contrast, an obvious difference has been observed in Δ Japanese Orthopedic Association (JOA) score (SMD = 0.305, 95%CI: 0.046 to 0.563, P = 0.021), total blood loss (SMD = -1.586, 95%CI: -2.182 to -0.990, P = 0.000), operation time (SMD = -2.831, 95%CI: -3.753 to -1.909, P = 0.000), and length of hospital stay (SMD = -0.614, 95%CI: -1.050 to -0.179, P = 0.006).

CONCLUSION

Bilateral fixation is more effective than unilateral fixation regarding fusion rate after lumbar interbody fusion. However, JOA, operation time, total blood loss, as well as length of stay were improved for unilateral fixation.

A novel surgical technique in transforaminal lumbar interbody fusion by the bone graft delivery device: evaluation of therapeutic effect in patients with minimally invasive spine surgery

Background

Transforaminal Lumbar Interbody Fusion (TLIF) is commonly associated with higher complications and longer operative time. This study aims to evaluate the effectiveness, safety, and usability of a novel minimally invasive surgery (MIS) bone graft delivery device.

Methods

73 consecutive patients with lumbar spondylosis, degenerative disc disease, spondylolisthesis, scoliosis or trauma were enrolled in this randomized controlled trial. Group 1 comprised 39 patients treated with the novel MIS bone graft delivery device. Group 2 consisted of 34 patients treated with the conventional system. The primary objective of the study was the assessment of the amount of bone graft delivery using the device. The secondary objectives were the effect of the device on operative time, pain relief, disability improvement, and bone fusion grade.

Results

Bone delivery amount was significantly higher in the MIS device group (6.7 ± 2.9 mL) compared to the conventional group (2.3 ± 0.5 mL), p < 0.001. Regarding the operation time, the MIS device group was associated significantly lower duration than the conventional group (p < 0.001). After a 3-month follow-up, 39.5% of the patients in the MIS device group and 3.5% of the patients in the conventional group were observed to achieve grade I fusion (complete fusion). There was a significant difference in fusion success rates (p < 0.01).

Conclusion

The novel MIS bone graft delivery device was associated with successful bone delivery. Our MIS device provides promising modality with less operative time and higher bone fusion rates than conventional modalities.

Trial Registration This trial was retrospectively registered on ClinicalTrials.gov (Registration date: 11/19/2021; Registration number: NCT05190055).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-022-01773-y.

Safety and efficacy of unilateral and bilateral pedicle screw fixation for lumbar degenerative diseases by transforaminal lumbar interbody fusion: An updated systematic review and meta-analysis

Background

The purpose of this study was to compare the safety and efficacy of unilateral vs. bilateral pedicle screw fixation (BPSF) for lumbar degenerative diseases.

Methods

Electronic databases including PubMed, Web of science, the Cochrane Library, Scopus, MEDLINE, EMBASE, EBSCO were searched by computer. The deadline was set for June 1, 2022. This study included all high-quality randomized controlled trials (RCTs), prospective clinical controlled studies (PRO), and retrospective studies (Retro) that compared unilateral and bilateral pedicle screw fixation in the treatment of lumbar degenerative diseases. Revman5.3 software was used for meta-analysis after two researchers independently screened the literature, extracted data, and assessed the risk of bias in the study.

Results

Fourteen studies with a total of 1,086 patients were included. Compared with BPSF, unilateral pedicle screw fixation (UPSF) has shorter operation time and hospital time, and less blood loss and operation cost, operation time [SMD = −1.75, 95% CI (−2.46 to −1.03), P < 0.00001], hospital time [SMD = −1.10, 95% CI (−1.97 to −0.22), P = 0.01], Blood loss [SMD = −1.62, 95% CI (−2.42 to −0.82), P < 0.0001], operation cost [SMD = −14.03, 95% CI (−20.08 to −7.98), P < 0.00001], the ODI after bilateral pedicle screw fixation was lower, and the degree of lumbar dysfunction was lighter, [SMD = 0.19, 95% CI (0.05–0.33), P = 0.007], better fusion effect, fusion rate [RR=0.95, 95% CI (0.91–1.00), P = 0.04]. VAS-Low back pain [SMD = 0.07, 95% CI (−0.07–0.20), P = 0.35], VAS-Leg pain [SMD = 0.18, 95% CI (−0.00–0.36), P = 0.05], SF-36 [SMD = 0.00, 95% CI (−0.30–0.30), P = 1.00], complications rate [RR = 0.94, 95% CI (0.9154–1.63), P = 0.82], the overall difference was not statistically significant.

Conclusions

Currently limited evidence suggests that UPSF significantly reduces blood loss, significantly shortens the operative time and hospital stay, and reduces blood loss and costs. After BPSF, the ODI was lower, the degree of lumbar spine dysfunction was lower, and the fusion rate was significantly higher. The VAS, SF-36, and complications scores of the two groups were comparable, and there was no significant clinical difference.

Unilateral versus Bilateral Pedicle Screw Instrumented Transforaminal Interbody Fusion in a Single Level Lumbar Spondylolisthesis

Background The study aims to assess the efficiency, safety and outcome of unilateral pedicle screw fixation with TLIF (Transforaminal lumbar interbody fusion) vs bilateral pedicle screw fixation with TLIF in cases of single level spondylolisthesis by comparing clinical, functional outcome and the complication rates. Methods We prospectively collected demographics and clinical data of the patients with surgically treated single level lumbar spondylolisthesis grade 1 (n=60) with follow up and comparison between clinical/functional outcomes and complication rates between January 2020 and January 2021 at Cairo University hospitals. We allocated the patients with the unilateral pedicle screw fixation with TLIF as group A and the patients with the bilateral pedicle screw fixation with TLIF as group B. Results Clinical outcome showed statistical significance between Group A and Group B (P-value < 0.001); Functional outcome (using Oswestry’s disability index) between group A and B also showed statistical significance (P-value < 0.001) in favor of group B. Complications in group A was higher especially cage migration in 26.7% of cases with p-value of 0.026 while it was only present in 3.3% of the group B cases. Conclusion We concluded that the bilateral approach showed a statistically significant better clinically/functional outcomes with lower rates of complication in comparison with the unilateral approach.

Outcomes of Transforaminal Lumbar Interbody Fusion Using Unilateral Versus Bilateral Interbody Cages

Objective

To assess the impact of bilateral versus unilateral interbody cages on outcomes for minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) procedures.

Methods

A retrospective review for primary, elective, single-level MIS TLIF procedures with bilateral posterior instrumentation from 2008–2020 was performed. Patients were grouped according to unilateral or bilateral interbody cage use. Procedures performed without static interbody cages or indicated for trauma, infection, malignancy were excluded. Patient-reported outcomes (PROs) included visual analogue scale (VAS), Oswestry Disability Index, 12-item Short Form health survey physical composite score (SF-12 PCS), PatientReported Outcome Measurement Information System physical function (PROMIS-PF). PROs were collected preoperatively and postoperatively. Change in PROs (Δ) was calculated and compared between groups. Achievement of minimum clinically important difference (MCID) was calculated using established values from the literature. Achievement rates were compared between groups using logistic regression.

Results

The study included 151 patients, with 111 unilateral and 40 bilateral cage placements. Charlson Comorbidity Index, diabetes, and insurance status differed between groups (p < 0.050). Prevalence of degenerative and isthmic spondylolisthesis (both p ≤ 0.002), operative level (p = 0.003), and postoperative length of stay (p = 0.022) significantly differed between groups. The unilateral group had lower 1-year arthrodesis rates (p = 0.035). Preoperative VAS leg (p = 0.017) and SF-12 PCS (p = 0.045) were worse for the unilateral group. ΔPROMIS-PF was greater for the bilateral group at 2 years (p = 0.001). Majority of patients achieved an overall MCID for all PROs, except VAS leg (bilateral group).

Conclusion

While preoperative status and postoperative arthrodesis rates differed, patients achieved an MCID at similar rates regardless of use of unilateral or bilateral cages.

Comparison of the Unilateral and the Bilateral Pedicle Screw Fixation without Using an Interbody Cage: Randomized Clinical Trial

BACKGROUND: Lumbar spine instability is one of the main causes of low back pain and has become more prevalent in recent years. Bilateral pedicle screw fixation is used to perform posterior lumbar stabilization, which is complemented by the installation of an interbody cage. AIM: The aim of the study was evaluating of the results of unilateral and bilateral pedicle screw fixation without using of an interbody cage. METHODS: A prospective randomized study of 96 patients was carried out. Forty-seven patients were assigned to the group of the unilateral pedicle screw fixation versus 49 patients were moved to the group of the bilateral pedicle screw fixation of the lumbar spine. Of the 96 patients, 80 patients eventually were included in the study. However, seven patients in the first group and nine patients were lost to follow-up. Surgery timing, blood loss volume, clinical outcomes (scores on the Oswestry disability index [ODI], EQ-5D and visual analogue scale [VAS]) were evaluated in 6–12 months after surgical treatment. All the patients included in this study underwent functional and control computed tomography in 12 months after surgery. RESULTS: Both groups showed a significant improvement in VAS, EQ-5D, and ODI in 1 year after surgical treatment. The two groups significantly differed in the surgery timing (unilateral – 90.2 min; and bilateral – 129.4 min) and blood loss volume (unilateral – 152.7 ml; and bilateral – 230.1 ml), p < 0.05. CONCLUSIONS: Unilateral and bilateral pedicle screw fixation showed similar clinical results, while results in both types of fixation differed in slight manner. However, the duration of surgical treatment and intraoperative blood loss volume proved to be lower for the unilateral fixation group, which indicates that the use of the unilateral fixation can be the choice of performing posterior stabilization at a single-level instability of the spine without using an interbody cage.

Unilateral versus bilateral pedicle screw fixation in lumbar fusion: A systematic review of overlapping meta-analyses

OBJECTIVES

To carry out a systematic review on the basis of overlapping meta-analyses that compare unilateral with bilateral pedicle screw fixation (PSF) in lumbar fusion to identify which study represents the current best evidence, and to provide recommendations of treatment on this topic.

METHODS

A comprehensive literature search in PubMed, Embase, and the Cochrane Library databases was conducted to identify meta-analyses that compare unilateral with bilateral PSF in lumbar fusion. Only meta-analyses exclusively covering randomized controlled trials were included. Study quality was evaluated using the Oxford Levels of Evidence and Assessment of Multiple Systematic Reviews (AMSTAR) instrument. Then, the Jadad decision algorithm was applied to select the highest-quality study to represent the current best evidence.

RESULTS

A total of 9 studies with Level II of evidence fulfilled the eligibility criteria and were included. The scores of AMSTAR criteria for them varied from 5 to 9 (mean 7.78). The current best evidence detected no significant differences between unilateral and bilateral PSF for short-segment lumbar fusion in the functional scores, length of hospital stay, fusion rate, and complication rate. However, unilateral PSF involved a remarkable decrease in operative time and blood loss but increase of cage migration when compared with bilateral PSF.

CONCLUSIONS

According to this systematic review, unilateral PSF is an effective method of fixation for short-segment lumbar fusion, has the advantages of reduced operative time and blood loss over bilateral PSF, but increases the risk of cage migration.

A Comparison Study of Three Posterior Fixation Strategies in Transforaminal Lumbar Interbody Fusion Lumbar for the Treatment of Degenerative Diseases

BACKGROUND

There are various posterior fixations utilized with transforaminal lumbar interbody fusion (TLIF). Previous studies have focused on the comparison of two fixation techniques.

MATERIALS AND METHODS

Sixty five patients with single-level lumbar disease were included in this retrospective study. Group A was treated by TLIF with bilateral pedicle screw (BPS), Group B treated by TLIF with unilateral pedicle screw (UPS), and Group C treated by TLIF with UPS plus contralateral translaminar facet screw (UPSFS). The operative time, blood loss, Oswestry disability index (ODI), Japanese Orthopaedic Association Scores (JOA), and visual analog scores (VAS) were recorded. Radiographic examination was used to assess fusion rates and incidence of screw failure.

RESULTS

The blood loss and operative times were 188.69 ± 37.69 ml and 132.96.5 ± 8.69 min in BPS group, 117.27 ± 27.11 ml and 99.32 ± 12.94 min in UPS group, and 121.50 ± 22.54 ml and 112.55 ± 9.42 min in UPSFS group; UPS and UPSFS were better than BPS (P < 0.05). The mean followup time was 38.2 months. Fusion rates were - BPS group: 95.6%, UPS group: 90%, UPSFS: 95% (P > 0.05). Screw and/or rod failures were found in three groups (BPS group: 1, UPS group: 2 and UPSFS: 1, P > 0.05). The average postoperative VAS, ODI, and JOA scores of BPS, UPS, and UPSFS were improved significantly in each group compared to preoperative scores (P < 0.05); there were no significant differences between any two groups at each followup time point (P > 0.05).

CONCLUSION

UPSFS with TLIF is a viable treatment option that provides satisfactory clinical results; the clinical outcome and the complication rate were comparable to BPS. In addition, the invasive of UPSFS cases was comparable to UPS and better than BPS cases. For UPS, it could be used in suitable patients.