Unilateral versus bilateral percutaneous pedicle screw fixation in minimally invasive transforaminal lumbar interbody fusion

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.

Tumor Embolization via the Meningohypophyseal and Inferolateral Trunk in Patients with Skull Base Tumors Using the Distal Balloon Protection Technique

BACKGROUND AND PURPOSE

Tumor embolization through the meningohypophyseal trunk and inferolateral trunk is known to be effective in skull base tumors; however, microcatheter cannulation into these arteries is difficult, and the number of cases that can be safely embolized is limited. In this study, we present a novel embolization procedure for the meningohypophyseal trunk and inferolateral trunk using the distal balloon protection technique and detail its clinical efficacy and complication risks. We developed this procedure to allow safe embolization in patients who cannot be adequately cannulated with microcatheters into these arteries.

MATERIALS AND METHODS

Patients who underwent meningohypophyseal trunk or inferolateral trunk embolization using the distal balloon protection technique for skull base tumors at our institution between 2010 and 2023 were included. In this procedure, the ICA was temporarily occluded with a balloon at the ophthalmic artery bifurcation, the microcatheter was guided to the meningohypophyseal trunk or inferolateral trunk vicinity, and embolic particles were injected into the arteries. The balloon was deflated after the embolic particles that had refluxed into the ICA were aspirated.

RESULTS

A total of 25 meningohypophyseal trunks and inferolateral trunks were embolized during 21 operations. Of these 25 arteries, only 9 (36.0%) were successfully cannulated with microcatheters. Nevertheless, effective embolization was achieved in all cases. Permanent complications occurred in only 1 case (4.8%) in which the central retinal artery was occluded during inferolateral trunk embolization, resulting in a visual field defect. No permanent complications resulting from the embolic cerebral infarction were observed. Of 16 cases that underwent MR imaging within a week after embolization, however, 11 (68.8%) demonstrated embolic cerebral infarctions.

CONCLUSIONS

In patients with skull base tumors with meningohypophyseal trunk or inferolateral trunk feeders that cannot be catheterized directly, embolization using the distal balloon protection technique for tumor supply can be considered as a salvage technique.

Comparison of Unilateral versus Bilateral Instrumented Transforaminal Lumbar Interbody Fusion in Lumbar Degenerative Diseases: A Minimum of 5-Year Follow-Up

Background and Objective: There is a paucity of literature comparing unilateral instrumented transforaminal lumbar interbody fusion (UITLIF) with bilateral instrumented TLIF (BITLIF) regarding radiological alignment, including the coronal balance, even though UITLIF might have asymmetric characteristics in the coronal plane. This retrospective study aimed to compare the clinical and long-term radiological outcomes of 1-level UITLIF and BITLIF in lumbar degenerative diseases (LDD) including lumbar spinal stenosis with or without spondylolisthesis (degenerative or spondylolytic). Materials and Methods: Patients who underwent 1-level UITLIF with two rectangular polyetheretherketone (PEEK) cages or BITLIF between November 2009 and June 2016 by four surgeons with ≥5 years of follow-up at a single hospital were included. We compared the clinical and radiological outcomes between the UITLIF and BITLIF. Results: In total, 63 and 111 patients who underwent UITLIF and BITLIF, respectively, were enrolled. The median follow-up was 85.55 months (range: 60-130). The UITLIF group had a significantly shorter operation time (185.0 [170.0-210.0] vs. 225.0 [200.0-265.0], p < 0.001) and lower estimated blood loss (300.0 [250.0-500.0] vs. 550.0 [400.0-800.0], p < 0.001) than the BITLIF group. Regarding the clinical outcomes, there were no significant differences in the intermittent claudication score (p = 0.495) and Kirkaldy-Willis criteria (p = 0.707) at 1 year postoperatively. The interval changes in the local coronal Cobb angle at the index level, L1-S1 lordotic angle, and coronal off-balance from the immediate postoperative radiograph to the last follow-up were not significantly different (p = 0.687, p = 0.701, and p = 0.367, respectively). Conclusions: UITLIF with two rectangular PEEK cages may provide comparable clinical outcomes and radiological longevity including coronal alignment to BITLIF in 1-level LDD. In addition, UITLIF has advantages over BITLIF in terms of operative time and blood loss.

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.

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.

Unilateral versus bilateral pedicle screw fixation with transforaminal lumbar interbody fusion for treatment of lumbar foraminal stenosis

BACKGROUND CONTEXT

Transforaminal lumbar interbody fusion (TLIF) with bilateral pedicle screw fixation (BPSF) is an effective treatment for lumbar foraminal stenosis (LFS). However, the effects of TLIF with unilateral pedicle screw fixation (UPSF) on LFS treatment have not been clearly elucidated.

PURPOSE

We conducted this study to compare clinical outcomes and radiographic results of TLIF with UPSF and BPSF 2 years after the surgical treatment.

DESIGN

Prospective randomized study.

PATIENT SAMPLE

This study included 23 patients undergoing TLIF with UPSF and 25 patients undergoing TLIF with BPSF.

OUTCOME MEASURES

Clinical outcomes were evaluated by visual analog scale (VAS) for low back pain and leg pain and Oswestry Disability Index (ODI) score. Radiographic outcomes included foraminal height, disc space height, segmental lordosis, and final fusion rates.

METHODS

The clinical and radiographic outcomes were compared between the UPSF and BPSF group. The postoperative improvements were evaluated in either group. Intraoperative data such as duration of operation and estimated blood loss were collected. This study was registered at clinicaltrials.gov.

RESULTS

Analysis of the VAS and ODI scores showed significant improvements in clinical outcomes within each group. No significant differences between the 2 groups were noted in the improvements of the VAS and ODI scores. The mean operative duration and blood loss were significantly greater in the BPSF group than in the UPSF group. There were significant improvements in the height of the foramen and intervertebral space and segmental lordosis in both groups, while there was no significant difference between the groups in amount of the improvements. No significant difference was found in the final fusion rates.

CONCLUSIONS

TLIF is an appropriate procedure for LFS treatment. With balanced intervertebral support using a cage, UPSF could achieve similar and satisfactory effects on lumbar segmental stability and fusion compared to BPSF. The unilateral approach appears to be associated with slightly shorter operative time and less blood loss.

MRI Assessment of the Early Disc Degeneration Two Levels above Fused Lumbar Spine Segment: A Comparison after Unilateral and Bilateral Transforaminal Lumbar Interbody Fusion (TLIF) Procedure

Background: Adjacent segment degeneration (ASD) has become a great concern as a late complication in patients following fusion spine surgery with a potential need for revision surgery. Segments above the fused spine have higher mobility and they are especially prone to accelerated disc degeneration. The purpose of our study is to investigate early disc degenerative changes two levels above a surgically fused lumbar spine segment and to compare MRI analyses after unilateral and bilateral TLIF procedures. Methods: A total of 117 patients were included in this cross-sectional retrospective single center study (after bilateral TLIF surgery: n = 91, and after unilateral TLIF: n = 26). In both groups, the average patient age was similar: 62.84 years (SD = 12.53) in the unilateral TLIF group and 60.67 years (SD = 11.89) in the bilateral TLIF group. On average, MRI was performed 2.5 years after surgery (SD = 2.09). The modified eight-level Pfirrmann grading system was used for the assessment of disc degeneration severity. Descriptive statistics and the Mann–Whitney test were used to show differences in the Pfirrmann grades regarding the after-surgery period and the patient age. The Wilcoxon signed-rank test results were used to display differences in the Pfirrmann grades before and after surgery. Results: The comparison of mean values, regardless of the type of surgery, shows that this mean value is on average higher in the first segment adjacent to the fused spine segment. The assessment of the intervertebral disc structure in BIL TLIF is higher in both the first and the second segment. Early disc degeneration progression is subtle yet detectable (UNI TLIF 9.28% vs. BIL TLIF 16.74%). The assessment of the intervertebral disc structure is on average lower in patients aged less than 50 years at time of surgery compared with patients aged more than 50 years in UNI TLIF, and higher in the BIL TLIF group, for both the first and the second segment. Conclusion: Patients who had undergone unilateral TLIF fusion surgery have a lower rate of early disc degenerative changes. Considering a significantly higher rate of progressive disc degenerative changes in the elderly with bilateral fusion surgery, extra caution is required in the selection of appropriate surgical technique.

What Affects Segmental Lordosis of the Surgical Site after Minimally Invasive Transforaminal Lumbar Interbody Fusion?

PURPOSE

This study was undertaken to identify factors that affect segmental lordosis (SL) after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) by comparing patients whose postoperative SL increased with those whose decreased.

MATERIALS AND METHODS

Fifty-five patients underwent MIS-TLIF at our institute from January 2018 to September 2019. Demographic, pre- and postoperative radiologic, and cage-related factors were included. Statistical analyses were designed to compare patients whose SL increased with decreased after surgery.

RESULTS

After surgery, SL increased in 34 patients (group I) and decreased in 21 patients (group D). The index level, disc lordosis, SL, lumbar lordosis, proximal lordosis (PL), and Y-axis position of the cage (Yc) differed significantly between groups I and D. The cage in group I was more anterior than that in group D (Yc: 55.84% vs. 51.24%). Multivariate analysis showed that SL decreased more significantly after MIS-TLIF when the index level was L3/4 rather than L4/5 [odds ratio (OR): 0.46, p=0.019], as preoperative SL (OR: 0.82, p=0.037) or PL (OR: 0.68, p=0.028) increased, and as the cage became more posterior (OR: 1.10, p=0.032).

CONCLUSION

Changes in SL after MIS-TLIF appear to be associated with preoperative SL and PL, index level, and Yc. An index level at L4/5 instead of L3/4, smaller preoperative SL or PL, and an anterior position of the cage are likely to result in increased SL after MIS-TLIF.

Systematic Review: Applications of Intraoperative Ultrasound in Spinal Surgery

BACKGROUND

Due to increased practicality and decreased costs and radiation, interest has risen for intraoperative ultrasound (iUS) in spinal surgery applications; however, few studies have provided a robust overview of its use in spinal surgery. We synthesize findings of existing literature on usage of iUS in navigation, pedicle screw placement, and identification of anatomy during spinal interventions.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were utilized in this systematic review. Studies were identified through PubMed, Scopus, and Google Scholar databases using the search string. Abstracts mentioning iUS in spine applications were included. Upon full-text review, exclusion criteria were implemented, including outdated studies or those with weak topic relevance or statistical power. Upon elimination of duplicates, multi-reviewer screening for eligibility, and citation search, 44 manuscripts were analyzed.

RESULTS

Navigation using iUS is safe, effective, and economical. iUS registration accuracy and success is within clinically acceptable limits for image-guided navigation (Table 2). Pedicle screw instrumentation with iUS is precise with a favorable safety profile (Table 2). Anatomical landmarks are reliably identified with iUS, and surgeons are overwhelmingly successful in neural or vascular tissue identification with iUS modalities including standard B mode, doppler, and contrast-enhanced ultrasound (CE-US) (Table 3). iUS use in traumatic reduction of fractures properly identifies anatomical structures, intervertebral disc space, and vasculature (Table 3).

CONCLUSION

iUS eliminates radiation, decreases costs, and provides sufficient accuracy and reliability in identification of anatomical and neurovascular structures in various spinal surgery settings.

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.

Minimally invasive transforaminal lumbar interbody fusion: Technical tips, learning curve, short-term clinical outcome, and brief review

Background

Current trends in spine surgeries have shifted to minimally invasive procedures. Minimally invasive approaches are getting more popular for lumbar interbody fusion procedures.

Objectives

The objective of the study was to report technical modifications, learning curve, and short-term clinical results in minimally invasive transforaminal interbody fusion (MITLIF).

Materials and Methods

All MITLIF cases performed from 2018 July to March 2020 were included. First three authors were operating surgeons. Visual analog scores (VAS) scoring for pain, Macnab criteria, and Oswestry disability index (ODI) were used for outcome assessment. Operating time, radiation exposure, and complications were assessed separately in a group of 20 as per time sequence in series to assess the learning curve.

Results

A total of 61 patients were included. Various indications included spondylolisthesis, failed back surgery, calcified lumbar disc, and spondylodiscitis. Mean age was 47.08 ± 12.06. Intraoperative blood loss was 97.04 ± 25.58. Mean operating time and number of C-arm shots were 190.75 ± 37.11 and 159.3 ± 74.54, respectively, in initial 20 cases which however reduced in later operated cases. Significant improvement in VAS and ODI scores was observed at follow-up of 6.34 ± 4.67 months. Three cases needed surgical revision in the initial 20 cases, and there were no revision surgeries in later operated cases.

Conclusion

MITLIF could be done in failed back surgery cases, spondylodiscitis, and deformity corrections in addition to spondylolisthesis. It has advantages of less injury to soft tissues, maintaining the posterior tension band, decrease in blood loss and hospital stays, and early mobilization. However, it has longer learning curve and takes minimum 20 cases for the surgeon to acquire reasonable experience and confidence.

Understanding the Future Prospects of Synergizing Minimally Invasive Transforaminal Lumbar Interbody Fusion Surgery with Ceramics and Regenerative Cellular Therapies

Transforaminal lumber interbody fusion (TLIF) is the last resort to address the lumber degenerative disorders such as spondylolisthesis, causing lower back pain. The current surgical intervention for these abnormalities includes open TLIF. However, in recent years, minimally invasive TLIF (MIS-TLIF) has gained a high momentum, as it could minimize the risk of infection, blood loss, and post-operative complications pertaining to fusion surgery. Further advancement in visualizing and guiding techniques along with grafting cage and materials are continuously improving the safety and efficacy of MIS-TLIF. These assistive techniques are also playing a crucial role to increase and improve the learning curve of surgeons. However, achieving an appropriate output through TLIF still remains a challenge, which might be synergized through 3D-printing and tissue engineering-based regenerative therapy. Owing to their differentiation potential, biomaterials such as stem/progenitor cells may contribute to restructuring lost or damaged tissues during MIS-TLIF, and this therapeutic efficacy could be further supplemented by platelet-derived biomaterials, leading to improved clinical outcomes. Thus, based on the above-mentioned strategies, we have comprehensively summarized recent developments in MIS-TLIF and its possible combinatorial regenerative therapies for rapid and long-term relief.

Comparison of clinical outcomes and spino-pelvic sagittal balance in degenerative lumbar spondylolisthesis: Minimally invasive oblique lumbar interbody fusion (OLIF) versus transforaminal lumbar interbody fusion (TLIF)

Spino-pelvic sagittal parameters are closely related to the lumbar degenerative diseases. The present study aims to compare clinical results and spino-pelvic sagittal balance treated with oblique lumbar interbody fusion (OLIF) and transforaminal lumbar interbody fusion (TLIF) in patients with degenerative lumbar spondylolisthesis at single segment.We retrospectively reviewed and compared 28 patients who underwent OLIF (OLIF group) and 35 who underwent TLIF (TLIF group). Radiological results were evaluated with disc height (DH), foraminal height (FH), fused segment lordosis (FSL), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), and sacral slope (SS). Clinical results were evaluated with the Oswestry Disability Index (ODI) and VAS for back and leg pain.The OLIF group showed higher improvement of DH and FH than the TLIF group at all time points after surgery (P < .05). No significant differences were found in PT, PI, and SS between the 2 groups (P > .05). Significant restoration of spino-pelvic sagittal balance was observed in the 2 groups after surgery. Significant differences in postoperative lumbar lordosis and fused segment lordosis were found between the 2 groups (P < .05). Significant difference in the improvement of symptoms was observed between the 2 groups. The OLIF group had lower VAS scores for back pain and ODI compared after surgery (P < .05).It can be concluded that there are exactly differences in improvement of radiographic parameters between 2 approaches, which confirmed that OLIF is better in restoring spinal alignment. Besides, due to the unique minimally invasive approach, OLIF did exhibit a greater advantage in early recovery after surgery.

Defining the MIS-TLIF: A Systematic Review of Techniques and Technologies Used by Surgeons Worldwide

STUDY DESIGN

Systematic review.

OBJECTIVE

To date there is no consensus among surgeons as to what defines an MIS-TLIF (transforaminal lumbar interbody fusion using minimally invasive spine surgery) compared to an open or mini-open TLIF. This systematic review aimed to examine the MIS-TLIF techniques reported in the recent body of literature to help provide a definition of what constitutes the MIS-TLIF, based on the consensus of the majority of surgeons.

METHODS

We created a database of articles published about MIS-TLIF between 2010 and 2018. We evaluated the technical components of the MIS-TLIF including instruments and incisions used as well the order in which key steps are performed.

RESULTS

We could identify several patterns for MIS-TLIF performance that seemed agreed upon by the majority of MIS surgeons: use of paramedian incisions; use of a tubular retractor to perform a total facetectomy, decompression, and interbody cage implantation; and percutaneous insertion of the pedicle-screw rod constructs with intraoperative imaging.

CONCLUSION

Based on this review of the literature, the key features used by surgeons performing MIS TLIF include the use of nonexpandable or expandable tubular retractors, a paramedian or lateral incision, and the use of a microscope or endoscope for visualization. Approaches using expandable nontubular retractors, those that require extensive subperiosteal dissection from the midline laterally, or specular-based retractors with wide pedicle to pedicle exposure are far less likely to be promoted as an MIS-based approach. A definition is necessary to improve the communication among spine surgeons in research as well as patient education.

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.

Unilateral Versus Bilateral Percutaneous Pedicle Screw Fixation in Oblique Lumbar Interbody Fusion

OBJECTIVE

To compare clinical and radiologic outcomes of unilateral pedicle screw (UPS) and bilateral pedicle screw (BPS) fixations after single-level oblique lateral interbody fusion procedures.

METHODS

This retrospective study included 74 patients receiving single-level oblique lateral interbody fusion at L3-4 or L4-5 (June 2014 to June 2017). These patients were divided into BPS (n = 36) and UPS (n = 38) groups. Perioperative outcomes included operative time, blood loss, medical expenses, and complication rates. Radiologic outcomes included fusion rates and cage subsidence rates. Clinical outcomes included disability measured by the Oswestry Disability Index and pain measured by the visual analog scale.

RESULTS

The operative time was significantly shorter in the UPS group (76.2 ± 4.4 minutes) compared with the BPS group (127.0 ± 5.6 minutes, P < 0.001). There was a significant between-group difference in medical expenses ($11,044.8 ± $470.7 in UPS group vs. $15,018.4 ± $547.1 in BPS, P < 0.001). Blood loss and hospital stay did not differ between groups. Oswestry Disability Index and visual analog scale scores significantly decreased in both groups at different time points postoperatively compared with preoperatively. The UPS group had lower Oswestry Disability Index and visual analog scale scores than the BPS group at 7 days postoperatively, but no between-group difference was found after 1-month follow-up. Fusion rate was 86.8% in UPS group and 91.7% in BPS group (P > 0.05). Cage subsidence rates did not differ between groups.

CONCLUSIONS

Oblique lateral interbody fusion with UPS fixation is an effective and reliable option for single-level lumbar diseases. Compared with BPS fixation, it resulted in less blood loss, required less operative time, and had comparable effects on radiologic and clinical outcomes.

Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF): A review of indications, technique, results and complications

Minimal access surgery has revolutionized most surgical disciplines and spine surgery is no exception. Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) was devised to reduce the approach-related morbidity of open TLIF and has flourished in the last decade. With expanding indications, standardization of technique and equipment, publication of more studies on its results and complications being brought to light - an update of the existing knowledge on MI-TLIF is imminent. We provide a review of the indications, technique, results and complications of MI-TLIF while also highlighting its variations and utility in special situations.

Reduction and monosegmental fusion for lumbar spondylolisthesis with a long tab percutaneous pedicle screw system: "swing" technique

OBJECTIVEWith the development of minimally invasive procedures, percutaneous pedicle screw systems have been used to attempt to correct spondylolisthesis. No previous studies have reported on reduction measures using long tab percutaneous pedicle screws for spondylolisthesis. Additional intraoperative correction has been proposed with the "swing" technique. This study was conducted to compare the efficacy of standard minimally invasive transforaminal interbody fusion (MIS-TLIF) with the efficacy of MIS-TLIF with the "swing" technique (MIS-TLIF and swing) in lumbar spondylolisthesis.METHODSThis was a matched-control study and included 30 consecutive patients who were followed up for 6 months after surgery. Of those patients, 15 were treated with operative reduction via MIS-TLIF with the "swing" technique, whereas the other 15 were treated with the standard MIS-TLIF procedure. The swing technique is a new reduction procedure for use with long tab percutaneous screws. In the swing technique, the entire system is swung back and forth several times after all constructs are placed. Only patients with Meyerding grade I or II lumbar spondylolisthesis were included in the study (18 with grade I and 12 with grade II). Perioperative and clinical outcomes, radiological parameters (Meyerding grade, percentage of slip, slip correction rate, segmental lordosis, and lumbar lordosis) were compared between groups at 6 months after surgery.RESULTSDemographic data did not differ significantly between the 2 groups. Postoperative clinical outcomes showed significant improvement in both groups. Postoperative radiological parameters showed that the degree of spondylolisthesis (swing: 4.7% vs standard: 8.9%) and reduction rate (swing: 77.3% vs standard: 57.1%) favored the swing group. The swing technique effectively decreased the degree of spondylolisthesis (swing: 24.1% to 4.7% vs standard: 21.8% to 8.9%). No complications related to the procedure were reported.CONCLUSIONSMIS-TLIF with the "swing" technique with long tab percutaneous pedicle screws is a safe and effective reduction method for monosegmental spondylolisthesis. This technique cannot only alleviate symptoms but also achieve nearly completely reduction of slippage.

Is unilateral pedicle screw fixation superior than bilateral pedicle screw fixation for lumbar degenerative diseases: a meta-analysis

Background

To investigate whether unilateral pedicle screw fixation is superior than bilateral pedicle screw fixation for lumbar degenerative diseases.

Methods

Electronic databases including PubMed, Embase, and the Cochrane Library up to August 2018 were searched. All the high-quality randomized controlled trials (RCTs) and prospective clinical controlled studies comparing the unilateral pedicle screw fixation and bilateral pedicle screw fixation for lumbar degenerative diseases were enrolled in this study. Fusion rate was the main outcome. Stata 12.0 was used for the meta-analysis.

Results

Twelve RCTs including 808 patients (unilateral pedicle screw fixation = 393, bilateral pedicle screw fixation = 415) were included in our meta-analysis. There was a significant difference between unilateral pedicle screw fixation and bilateral pedicle screw fixation in terms of the fusion rate (risk ratio (RR) = 0.96, 95%CI [0.92, 1.00], P = 0.073), visual analog scale (VAS) at final follow-up, Oswestry Disability Index (ODI), Japanese Orthopedic Association scores (JOA), short-form health survey (SF-36), and length of hospital stay. Compared with bilateral pedicle screw fixation, unilateral pedicle screw fixation was associated with a reduction of the total blood loss and operation time (P < 0.05). Unilateral pedicle screw fixation was associated with an increase of the cage migration than bilateral pedicle screw fixation (17.1% vs 7.1%, RR = 2.40, 95% CI = 1.17 to 4.93; P = 0.017).

Conclusions

Unilateral pedicle screw fixation and bilateral pedicle screw fixation has similar fusion rate when treating for lumbar degenerative diseases. Our meta-analysis suggested that compared with bilateral pedicle screw fixation, unilateral pedicle screw fixation significantly reduced total blood loss and operation time for lumbar degenerative diseases. The use of unilateral pedicle screw for lumbar degenerative diseases increases the cage migration.

Do we need a transforaminal lumbar interbody fusion cage to increase the stability of functional spinal unit when comparing unilateral and bilateral fixation?

Transforaminal lumbar interbody fusion was an alternative to posterior lumbar interbody fusion for decompression surgeries. This study investigates the biomechanical responses of the unilateral and bilateral pedicle screw fixations with/without transforaminal lumbar interbody fusion cages under axial compression, flexion, and torsional loads. Ovine vertebrae were used in this study. Cadavers, randomly divided into five, were intact control group, bilateral pedicle screw fixation group, bilateral pedicle screw fixation group with transforaminal lumbar interbody fusion cage, unilateral pedicle screw fixation group, and unilateral pedicle screw fixation group with transforaminal lumbar interbody fusion cage. Axial compression, flexion, and torsion tests were performed on specimens. All study groups provided higher stiffness and yield load values than control group under axial compression. Addition of transforaminal lumbar interbody fusion cage to bilateral fixation increased the stiffness under axial compression. Moreover, additional use of transforaminal lumbar interbody fusion in unilateral fixation increased the yield load values under axial compression. Control group was the stiffest in flexion test. Placing a transforaminal lumbar interbody fusion cage to both unilateral and bilateral fixations did not significantly change the stiffness values. Additional transforaminal lumbar interbody fusion cage increased the yield moment of the bilateral fixation. In torsion test, control group had the highest stiffness and yield torque. The facet joints are the most important parts of the vertebrae on the stability. When comparing the bilateral and unilateral fixations with transforaminal lumbar interbody fusion addition, the more facet preserving approach has significantly higher stability under axial compression, flexion, and torsion. Unilateral fixation with transforaminal lumbar interbody fusion cage can be said biomechanically stable and advantageous fixation system because of the advantage on the less facet and soft tissue resection compared to bilateral fixation with transforaminal lumbar interbody fusion.

Spinal Biologics in Minimally Invasive Lumbar Surgery

As the use of minimally invasive spine (MIS) fusion approaches continues to grow, increased scrutiny is being placed on its outcomes and efficacies against traditional open fusion surgeries. While there are many factors that contribute to the success of achieving spinal arthrodesis, selecting the optimal fusion biologic remains a top priority. With an ever-expanding market of bone graft substitutes, it is important to evaluate each of their use as it pertains to MIS techniques. This review will summarize the important characteristics and properties of various spinal biologics used in minimally invasive lumbar surgeries and compare their fusion rates via a systematic review of published literature.

Minimally Invasive Versus Open Laminectomy/Discectomy, Transforaminal Lumbar, and Posterior Lumbar Interbody Fusions: A Systematic Review

Minimally invasive spine surgeries (MISS) are becoming increasingly favored as alternatives to open spine procedures because of the reduced blood loss, postoperative pain, and recovery time. Studies have shown mixed results regarding the efficacy and safety of minimally invasive procedures compared to the traditional, open counterparts. The objectives of this systematic analysis are to compare clinical outcomes between the three MISS and open procedures: (1) laminectomy/discectomy, (2) transforaminal lumbar interbody fusion (TLIF), and (3) posterior lumbar interbody fusion (PLIF). The Cochrane and PubMed databases were queried according to the preferred reporting items for systematic review and meta-analyses (PRISMA) statement. The primary outcome measures included the visual analog scale (VAS), the Oswestry disability index (ODI), and blood loss. A total of 32 studies were included in the analysis. Of the three procedures investigated, only MISS TLIF showed significantly improved VAS for leg pain (p = 0.02), ODI (p = 0.05), and reduced blood loss (p = 0.005). MISS-laminectomy/discectomy, TLIF, and PLIF appear to be similar in terms of postoperative pain and perioperative blood loss. MISS TLIF is perhaps more effective in specific outcome measures and results in less intraoperative blood loss than open TLIF.

Unilateral Versus Bilateral Pedicle Screw Fixation in Transforaminal Lumbar Interbody Fusion: A Monocentric Study of 215 Patients With a Minimum of 4-Year Follow-up

STUDY DESIGN

A retrospective clinical study.

OBJECTIVE

This study sought to retrospectively compare the mid-term to long-term outcomes between unilateral pedicle screw (UPS) and bilateral pedicle screw (BPS) augmented transforaminal lumbar interbody fusion (TLIF) in lumbar degenerative diseases.

SUMMARY OF BACKGROUND DATA

Recently, UPS fixation has been applied in TLIF, for its satisfactory clinical outcome, less implants and less invasiveness. However, only short-term outcome has been reported, the mid-term to long-term outcome has not been well characterized.

MATERIALS AND METHODS

From June 2007 to February 2011, 215 of 348 consecutive patients suffering from lumbar degenerative diseases were operated in our hospital and accomplished a minimum of 4-year follow-up. These patients were divided into 2 groups according to the operative techniques: UPS group (n=109), and bilateral pedicle screw group (n=106). Operative time, blood loss, length of hospital stay, hospital bill, fusion status, and complications were recorded and analyzed statistically. Visual analog scale, Oswestry disability index, and Japanese Orthopaedic Association scores were used to assess the preoperative and postoperative pain and functional outcome.

RESULTS

The mean follow-up duration was 52.2 months. A significant decrease occurred in operative time, blood loss, and hospital bill in unilateral group, compared with bilateral group (P<0.05). The average postoperative visual analog scale, Oswestry disability index, and Japanese Orthopaedic Association scores improved significantly in each group than the preoperative counterparts (P<0.05); however, there were no significant difference between groups at any follow-up time point (P>0.05). No statistically difference was detected regarding fusion rate and complication rate between the 2 groups (P>0.05), except the cage migration rate (P<0.05).

CONCLUSIONS

UPS fixation could achieve satisfactory clinical outcome similar to bilateral fixation in TLIF at a mid-term to long-term follow-up. To avoid cage migration, bullet-shaped cages should not be used in the unilateral group.

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

PURPOSE

To evaluate the effectiveness and safety of unilateral pedicle screw fixation in transforaminal lumbar interbody fusion (TLIF) by comparing with bilateral pedicle screw fixation.

MATERIALS AND METHODS

PubMed, EMBASE, and the Cochrane Central Register of Controlled Trial database were used to search and identify clinical prospective trials that evaluated the efficacy and safety of unilateral fixation as compared with bilateral fixation in TLIF surgery. The methodological qualities of studies were assessed using the PEDro (Physiotherapy Evidence Database) score and Newcastle-Ottawa Scale.

RESULTS

Fourteen prospective studies comprising 954 participants were analyzed. Data synthesis show lower fusion rate (P = 0.03) and more cage migration (P = 0.04) in unilateral group compared to bilateral group. There was no significant difference in visual analog scale (VAS), Oswestry Disability Index (ODI), the Short Form 36 Health Survey (SF-36) physical component score (PCS), and length of hospital stay between unilateral and bilateral groups. The unilateral group had shorter operative time (P < 0.00001) and less blood loss (P = 0.0007).

CONCLUSIONS

Based on this systematic review and meta-analysis, the unilateral fixation in TLIF may achieve a similar clinical outcome and reduce blood loss and operative time when compared with that in bilateral fixation. However, the unilateral fixation may produce lower fusion rate and more cage migration than bilateral fixation in TLIF.

Three-year postoperative outcomes between MIS and conventional TLIF in1-segment lumbar disc herniation

AIM

The aim of this study is to assess the long-term clinical and radiological outcomes between minimally invasive (MIS) and conventional transforaminal lumbar interbody fusion (TLIF) in treating one-segment lumbar disc herniation (LDH).

MATERIAL AND METHODS

One-hundred and six patients treated by MIS-TLIF (50 cases) or conventional TLIF (56 cases) were included. Perioperative results were evaluated. Clinical outcomes were compared preoperatively and postoperatively. Radiologic parameters were based on a comparison of preoperative and three-year postoperative lumbar lordosis, segmental lordosis, sacral slope, the cross-sectional area of the paraspinal muscle and fusion rates.

RESULTS

MIS TILF had significantly less blood, shorter operation time, mean return to work time and lower intramuscular pressure compared with the conventional group during the operation. VAS scores for lower back pain and ODI in MIS-TLIF were significantly decreased. The mean cross-sectional area of the paraspinal muscle was significantly decreased after surgery in the conventional TLIF group and no significant intragroup differences were established in the MIS-TLIF group. No significant differences were found in fusion rate, lumbar lordosis, segmental lordosis and sacral slope.

CONCLUSIONS

Both MIS and conventional TLIF were beneficial for patients with LDH. However, MIS-TLIF manifests a great improvement in perioperative outcomes, low back pain, disability and preventing paraspinal muscle atrophy during the follow-up period observation.

Clinical outcomes after minimally invasive transforaminal lumbar interbody fusion and lateral lumbar interbody fusion for treatment of degenerative lumbar disease: a systematic review and meta-analysis

The surgical procedures used for arthrodesis in the lumbar spine for degenerative lumbar diseases remain controversial. This systematic review aims to assess and compare clinical outcomes along with the complications and fusion of each technique (minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) or minimally invasive lateral lumbar interbody fusion (MIS LLIF)) for treatment of degenerative lumbar diseases. Relevant studies were identified from Medline and Scopus from inception to July 19, 2016 that reported Oswestry Disability Index (ODI), back and leg pain visual analog score (VAS), postoperative complications, and fusion of either technique. Fifty-eight studies were included for the analysis of MIS-TLIF; 40 studies were included for analysis of LLIF, and 1 randomized controlled trial (RCT) study was included for comparison of MIS-TLIF to LLIF. Overall, there were 9506 patients (5728 in the MIS-TLIF group and 3778 in the LLIF group). Indirect meta-analysis, MIS-TLIF provided better postoperative back and leg pain (VAS), disabilities (ODI), and risk of having complications when compared to LLIF technique, but the fusion rate was not significantly different between the two techniques. However, direct meta-analysis between RCT study and pooled indirect meta-analysis of MIS-TLIF have better pain, disabilities, and complication but no statistically significant difference when compared to LLIF. In LLIF, the pooled mean ODI and VAS back pain were 2.91 (95% CI 2.49, 3.33) and 23.24 (95% CI 18.96, 27.51) in MIS approach whereas 3.14 (95% CI 2.29, 4.04) and 28.29 (95% CI 21.92, 34.67) in traditional approach. In terms of complications and fusion rate, there was no difference in both groups. In lumbar interbody fusion, MIS-TLIF had better ODI, VAS pain, and complication rate when compared to LLIF with direct and indirect meta-analysis methods. However, in terms of fusion rates, there were no differences between the two techniques.

Comparison of complication rates of minimally invasive transforaminal lumbar interbody fusion and lateral lumbar interbody fusion: a systematic review of the literature

OBJECT Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and lateral lumbar interbody fusion (LLIF) are 2 currently popular techniques for lumbar arthrodesis. The authors compare the total risk of each procedure, along with other important complication outcomes. METHODS This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant studies (up to May 2015) that reported complications of either MI-TLIF or LLIF were identified from a search in the PubMed database. The primary outcome was overall risk of complication per patient. Secondary outcomes included risks of sensory deficits, temporary neurological deficit, permanent neurological deficit, intraoperative complications, medical complications, wound complications, hardware failure, subsidence, and reoperation. RESULTS Fifty-four studies were included for analysis of MI-TLIF, and 42 studies were included for analysis of LLIF. Overall, there were 9714 patients (5454 in the MI-TLIF group and 4260 in the LLIF group) with 13,230 levels fused (6040 in the MI-TLIF group and 7190 in the LLIF group). A total of 1045 complications in the MI-TLIF group and 1339 complications in the LLIF group were reported. The total complication rate per patient was 19.2% in the MI-TLIF group and 31.4% in the LLIF group (p < 0.0001). The rate of sensory deficits and temporary neurological deficits, and permanent neurological deficits was 20.16%, 2.22%, and 1.01% for MI-TLIF versus 27.08%, 9.40%, and 2.46% for LLIF, respectively (p < 0.0001, p < 0.0001, p = 0.002, respectively). Rates of intraoperative and wound complications were 3.57% and 1.63% for MI-TLIF compared with 1.93% and 0.80% for LLIF, respectively (p = 0.0003 and p = 0.034, respectively). No significant differences were noted for medical complications or reoperation. CONCLUSIONS While there was a higher overall complication rate with LLIF, MI-TLIF and LLIF both have acceptable complication profiles. LLIF had higher rates of sensory as well as temporary and permanent neurological symptoms, although rates of intraoperative and wound complications were less than MI-TLIF. Larger, prospective comparative studies are needed to confirm these findings as the current literature is of relative poor quality.

Lumbar Interspinous Process Fixation and Fusion with Stand-Alone Interlaminar Lumbar Instrumented Fusion Implant in Patients with Degenerative Spondylolisthesis Undergoing Decompression for Spinal Stenosis

STUDY DESIGN

Prospective cohort study.

PURPOSE

To assess the ability of a stand-alone lumbar interspinous implant (interspinous/interlaminar lumbar instrumented fusion, ILIF) associated with bone grafting to promote posterior spine fusion in degenerative spondylolisthesis (DS) with vertebral instability.

OVERVIEW OF LITERATURE

A few studies, using bilateral laminotomy (BL) or bilateral decompression by unilateral laminotomy (BDUL), found satisfactory results in stenotic patients with decompression alone, but others reported increased olisthesis, or subsequent need for fusion in DS with or without dynamic instability.

METHODS

Twenty-five patients with Grade I DS, leg pain and chronic low back pain underwent BL or BDUL and ILIF implant. Olisthesis was 13% to 21%. Follow-up evaluations were performed at 4 to 12 months up to 25 to 44 months (mean, 34.4). Outcome measures were numerical rating scale (NRS) for back and leg pain, Oswestry disability index (ODI) and short-form 36 health survey (SF-36) of body pain and function.

RESULTS

Fusion occurred in 21 patients (84%). None had increased olisthesis or instability postoperatively. Four types of fusion were identified. In Type I, the posterior part of the spinous processes were fused. In Type II, fusion extended to the base of the processes. In Type III, bone was present also around the polyetheretherketone plate of ILIF. In Type IV, even the facet joints were fused. The mean NRS score for back and leg pain decreased by 64% and 80%, respectively. The mean ODI score was decreased by 52%. SF-36 bodily pain and physical function mean scores increased by 53% and 58%, respectively. Computed tomography revealed failed fusion in four patients, all of whom still had vertebral instability postoperatively.

CONCLUSIONS

Stand-alone ILIF with interspinous bone grafting promotes vertebral fusion in most patients with lumbar stenosis and unstable Grade I DS undergoing BL or BDUL.

A biomechanical comparison of 3 different posterior fixation techniques for 2-level lumbar spinal disorders

OBJECT

This study sought to make a biomechanical comparison of 3 different posterior fixation techniques for 2-level lumbar spinal disorders.

METHODS

Eight fresh-frozen human cadaver lumbar spines (4 from L-1 to L-5, 4 from L-1 to S-1) were tested by applying pure moments of ± 8 Nm. Each specimen was first tested intact, and then the left facetectomies of L3-4 and L4-5 were performed to establish an unstable condition without removal of discs. Three instrumentation systems were then tested randomly: unilateral pedicle screw (UPS), UPS with contralateral translaminar facet screw (UPSFS), and bilateral pedicle screw (BPS). The range of motion (ROM) and the neutral zone (NZ) of L3-5 were measured.

RESULTS

All fixation types could reduce the ROM of L3-5 significantly in flexion, extension, and lateral bending, compared with the intact state. In axial torsion, only BPS reduced the ROM significantly, compared with the intact state. The UPSFS technique provided intermediate stability, which was superior to the UPS in flexion-extension and lateral bending, and inferior to the BPS in lateral bending. Compared with the intact state, the NZs decreased significantly for UPS, UPSFS, and BPS in flexion-extension, while not significantly in lateral bending and axial torsion.

CONCLUSIONS

In this study, among the 3 fixation techniques, BPS offered the highest stability, UPSFS provided intermediate stability, and UPS was the least stable for 2-level lumbar spinal disorders. UPSFS appeared to be able to offer a less invasive choice than BPS in well-selected patients with 2-level lumbar spinal disorders.

Minimally Invasive Unilateral vs. Bilateral Pedicle Screw Fixation and Lumbar Interbody Fusion in Treatment of Multi-Segment Lumbar Degenerative Disorders

Background

The choice for instrumentation with minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in treatment of degenerative lumbar disorders (DLD) remains controversial. The goal of this study was to investigate clinical outcomes in consecutive patients with multi-segment DLD treated with unilateral pedicle screw (UPS) vs. bilateral pedicle screw (BPS) instrumented TLIF.

Material/Methods

Eighty-four consecutive patients who had multi-level MIS-TLIF were retrospectively reviewed. All data were collected to compare the clinical outcomes between the 2 groups.

Results

Both groups showed similar clinical function scores in VAS and ODI. The two groups differed significantly in operative time (P<0.001), blood loss (P<0.001), and fusion rate (P=0.043), respectively.

Conclusions

This study demonstrated similar clinical outcomes between UPS fixation and BPS procedure after MIS-TLIF for multi-level DLD. Moreover, UPS technique was superior in operative time and blood loss, but represented lower fusion rate than the BPS construct did.

Minimally Invasive Transforaminal Lumbar Interbody Fusion in Multilevel: Comparison with Conventional Transforaminal Interbody Fusion

OBJECTIVE

Minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF) has shown superior or noninferior results compared with conventional TLIF in single segments. There were no comparative studies between MIS and conventional TLIF in multisegments. The purpose of this study was to compare MIS and conventional TLIF in multisegments.

METHODS

This is a cross-sectional study of 2- or 3-segment lumbar degenerative disease that was treated with either MIS (27 cases) or conventional TLIF (43 cases). Whole spine sagittal radiography was done preoperatively and 1 year after surgery. Clinical outcomes, perioperative outcomes, and fusion rate were compared. Radiologic parameters, such as cervical lordosis, thoracic kyphosis, lumbar lordosis, sagittal vertical axis, and pelvic parameters, were measured 1 year after surger.

RESULTS

The two groups were similar in age, sex, preoperative diagnosis, operated level, and follow-up period. Both groups showed improvement in visual analog scale and Oswestry disability index after surgery. The MIS TILF group had a significantly shorter operation time (167.10 vs. 216.58 minutes) and less blood loss (532.41 vs. 865.81 mL). Only cervical lordosis (MIS TLIF, -17.2°; conventional TLIF, -11.2°) was significantly different preoperatively between the groups. Postoperatively, there were no significant differences in radiologic parameter and fusion rate. In the intragroup comparisons, thoracic kyphosis, lumbar lordosis, and sacral slope were significantly increased and pelvic tilt was significantly decreased after surgery.

CONCLUSIONS

MIS TLIF and conventional TLIF showed similar clinical and radiologic outcomes. MIS TLIF may be a better choice for 2- or 3-segment lumbar fusion in perioperative outcomes.

Comparison of transforaminal lumbar interbody fusion performed with unilateral pedicle screw fixation or unilateral pedicle screw-contralateral percutaneous transfacet screw fixation

PURPOSE

To determine whether unilateral pedicle screw fixation is comparable with unilateral pedicle screw and contralateral percutaneous transfacet screw fixation in single-level lumbar spinal fusion.

METHODS

Fifty-eight patients were divided into either unilateral (n = 32) or unilateral pedicle screw and contralateral percutaneous transfacet screw fixation (n = 26) instrumentation groups. The operating time, blood loss, length of hospital stay, clinical outcomes, total lumbar scoliotic changes, and fusion and complication rates were compared between the two groups.

RESULTS

There were no significant differences between the two groups in blood loss, length of hospital stay, clinical results, total lumbar scoliotic changes, and fusion and complication rates. There were significant differences in duration of operating time between 2 groups.

CONCLUSIONS

Unilateral pedicle screw fixation may be as effective as unilateral PS with contralateral percutaneous transfacet screw fixation for the treatment of lumbar degenerative disorders.

Bilateral pedicle screw fixation provides superior biomechanical stability in transforaminal lumbar interbody fusion: a finite element study

BACKGROUND CONTEXT

Transforaminal lumbar interbody fusion (TLIF) is increasingly popular for the surgical treatment of degenerative lumbar disease. The optimal construct for segmental stability remains unknown.

PURPOSE

To compare the stability of fusion constructs using standard (C) and crescent-shaped (CC) polyetheretherketone TLIF cages with unilateral (UPS) or bilateral (BPS) posterior instrumentation.

STUDY DESIGN

Five TLIF fusion constructs were compared using finite element (FE) analysis.

METHODS

A previously validated L3-L5 FE model was modified to simulate decompression and fusion at L4-L5. This model was used to analyze the biomechanics of various unilateral and bilateral TLIF constructs. The inferior surface of the L5 vertebra remained immobilized throughout the load simulation, and a bending moment of 10 Nm was applied on the L3 vertebra to recreate flexion, extension, lateral bending, and axial rotation. Various biomechanical parameters were evaluated for intact and implanted models in all loading planes.

RESULTS

All reconstructive conditions displayed decreased motion at L4-L5. Bilateral posterior fixation conferred greater stability when compared with unilateral fixation in left lateral bending. More than 50% of intact motion remained in the left lateral bending with unilateral posterior fixation compared with less than 10% when bilateral pedicle screw fixation was used. Posterior implant stresses for unilateral fixation were six times greater in flexion and up to four times greater in left lateral bending compared with bilateral fixation. No effects on segmental stability or posterior implant stresses were found. An obliquely-placed, single standard cage generated the lowest cage-end plate stress.

CONCLUSIONS

Transforaminal lumbar interbody fusion augmentation with bilateral posterior fixation increases fusion construct stability and decreases posterior instrumentation stress. The shape or number of interbody implants does not appear to impact the segmental stability when bilateral pedicle screws are used. Increased posterior instrumentation stresses were observed in all loading modes with unilateral pedicle screw/rod fixation, which may theoretically accelerate implant loosening or increase the risk of construct failure.

Minimally invasive unilateral versus bilateral technique in performing single-segment pedicle screw fixation and lumbar interbody fusion

Purpose

The minimally invasive transforaminal lumbar interbody fusion procedure with percutaneous pedicle screws was adopted in clinical practice, but the choice between a unilateral pedicle screw (UPS) or bilateral pedicle screw (BPS) fixation after lumbar fusion remains controversial. The purpose of the present retrospective study was to compare the clinical outcomes and radiological results of unilateral and bilateral pedicle screw fixations.

Methods

The retrospective study recruited seventy-eight patients with a single-level pedicle screw fixation and lumbar interbody fusion at L4–L5 or L5–S1 from January 2010 to January 2013. The patients were treated with MIS TLIF with BPS fixation, and since May 2012, all patients were treated with UPS fixation. The perioperative outcomes including operative time, blood loss, hospital-stay length, and complication rates were accessed. Radiological outcomes regarding fusion were determined with the Bridwell grading system. Clinical outcomes were evaluated with the Oswestry Disability Index (ODI) and visual analog scale (VAS) during the mean follow-up of 2 years.

Results

According to perioperative assessments, the operative time was significantly shorter for group UPS (84.7 ± 6.4 min) than for group BPS (103.6 ± 10.6 min; p < 0.0001), and similar results were found with regard to the mean blood loss (UPS, 96.3 ± 17.5; BPS, 137.4 ± 32.9, p < 0.0001). With regard to the hospital-stay period, though the UPS group seems shorter, there is no statistical significance (UPS, 10.0 ± 2.1; BPS, 10.4 ± 2.4, p = 0.428). There were four in the BPS group and six in the UPS group defined as unfused at 6 months pest-operative, but at 12 months post-surgery, all patients achieved solid fusion. Regarding clinical outcomes, the VAS and ODI scores were significantly lower in the UPS group than the BPS group at 7 days post-surgery, but there was no difference at 1 month post-surgery and during the later follow-up.

Conclusion

There was no difference between the UPS and BPS flexion techniques about the clinical outcomes at 24 months post-surgery. However, because the UPS involves a shorter surgical time, less blood loss, faster pain relief, and faster functional recovery, UPS might be more suitable in performing single-segment pedicle screw fixation and lumbar interbody fusion.

Unilateral versus bilateral pedicle screw fixation in short-segment lumbar spinal fusion: a meta-analysis of randomised controlled trials

OBJECTIVE

We performed this meta-analysis of randomised controlled trials to compare the efficacy and safety of unilateral with bilateral fixation in short-segment lumbar spinal fusion.

METHODS

Predefined terms were used to search electronic databases to identify relevant research. Randomised controlled trials (RCTs) published in English and Chinese during 1990-2015 investigating efficacy and safety of unilateral and bilateral fixation in short-segment lumbar spinal fusion were included. Data of fusion rate, complications, visual analogue scale (VAS), Oswestry Disability Index (ODI), estimated blood loss (EBL) and length of hospital stay were extracted and analysed. Two reviewers independently searched information sources, selected eligible research, analysed data and evaluated risk of bias.

RESULTS

Eleven RCTs comprising 756 participants were analysed. There was no significant difference in fusion rate, device-related complication, ODI, VAS and length of hospital stay between bilateral and unilateral groups. The unilateral group had the obvious advantage of reduced blood loss [mean difference (MD) -143.57, 95 % confidence interval (Cl) -206.61 to -80.54, P < 0.0001) and operation time (MD -52.72, 95 % Cl -73.58 to -31.87, P < 0.00001).

CONCLUSION

Unilateral pedicle screw fixation is equally as effective as bilateral pedicle screw fixation in short-segment lumbar spinal fusion and may reduce operation time and blood loss.

Minimally Invasive Transforaminal Lumbar Interbody Fusion for Spondylolisthesis: Comparison Between Isthmic and Degenerative Spondylolisthesis

INTRODUCTION

Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) is a common surgical option for degenerative spondylolisthesis (DS). However, its effectiveness for isthmic spondylolisthesis (IS) is still controversial. No current studies have directly compared perioperative and postoperative results including various radiological parameters between IS and DS after MIS TLIF.

PURPOSE

The purpose of this study is to compare the clinical and radiological results between isthmic and degenerative spondylolisthesis after MIS TLIF.

METHODS

This is a retrospective study of 41 patients who underwent MIS TLIF for single-segment, grade 1 or 2 IS (n = 18) and DS (n = 23). The same surgical techniques and procedure were applied to both groups. Perioperative outcomes (operation time, blood loss, hospital stay, complications); clinical outcomes (visual analog scale [VAS], Oswestry Disability Index [ODI]); radiological parameters (disk height, degree of spondylolisthesis, slip angle, lumbar lordosis, segmental lordosis, sacropelvic parameters: pelvic incidence, sacral slope, pelvic tile); and fusion rates using computed tomography scanning were compared between groups at 1 year postoperatively.

RESULTS

There were no significantly different perioperative results between groups. Mean VAS and ODI scores improved significantly postoperatively in both groups but were not significantly different between groups at each follow-up point. Radiological parameters were not significantly different between groups except disk height and degree of spondylolisthesis. The disk heights were increased postoperatively (IS: 6.79-9.22 mm; DS: 8.18-8.97 mm) in both groups, and there were significant differences preoperatively. In addition, disk height restoration was greater for IS than DS (2.43 mm vs. 0.79 mm, P = 0.01). However, postoperative disk heights were not significantly different between groups. The degree of spondylolisthesis was significantly different between groups both preoperatively (16.77% vs. 11.33%, P < 0.01) and postoperatively (9.79% vs. 3.78%, P < 0.01). However, slip reduction was no different between groups (6.97 vs. 7.56%, P = 0.74). Fusion rates were not significantly different between groups.

CONCLUSIONS

MIS TLIF resulted in similar clinical outcomes when used to treat both isthmic and degenerative spondylolisthesis. Although disk height restoration was more effective for IS than DS, other radiological parameters including fusion rate were no different between groups. For both isthmic and degenerative spondylolisthesis, MIS TLIF can be a safe and effective surgical option.

Quality and Quantity of Published Studies Evaluating Lumbar Fusion during the Past 10 Years: A Systematic Review

Study Design Systematic review. Clinical Questions (1) Has the proportion and number of randomized controlled trials (RCTs) as an indicator of quality of evidence regarding lumbar fusion increased over the past 10 years? (2) Is there a difference in the proportion of RCTs among the four primary fusion diagnoses (degenerative disk disease, spondylolisthesis, deformity, and adjacent segment disease) over the past 10 years? (3) Is there a difference in the type and quality of clinical outcomes measures reported among RCTs over time? (4) Is there a difference in the type and quality of adverse events measures reported among RCTs over time? (5) Are there changes in fusion surgical approach and techniques over time by diagnosis over the past 10 years? Methods Electronic databases and reference lists of key articles were searched from January 1, 2004, through December 31, 2013, to identify lumbar fusion RCTs. Fusion studies designed specifically to evaluate recombinant human bone morphogenetic protein-2 or other bone substitutes, revision surgery studies, nonrandomized comparison studies, case reports, case series, and cost-effectiveness studies were excluded. Results Forty-two RCTs between January 1, 2004, and December 31, 2013, met the inclusion criteria and form the basis for this report. There were 35 RCTs identified evaluating patients diagnosed with degenerative disk disease, 4 RCTs evaluating patients diagnosed with degenerative spondylolisthesis, and 3 RCTs evaluating patients with a combination of degenerative disk disease and degenerative spondylolisthesis. No RCTs were identified evaluating patients with deformity or adjacent segment disease. Conclusions This structured review demonstrates that there has been an increase in the available clinical database of RCTs using patient-reported outcomes evaluating the benefit of lumbar spinal fusion for the diagnoses of degenerative disk disease and degenerative spondylolisthesis. Gaps remain in the standardization of reportage of adverse events in such trials, as well as uniformity of surgical approaches used. Finally, continued efforts to develop higher-quality data for other surgical indications for lumbar fusion, most notably in the presence of adult spinal deformity and revision of prior surgical fusions, appear warranted.

Unilateral versus Bilateral Instrumentation in Spinal Surgery: A Systematic Review

Study Design Systematic review. Clinical Questions (1) What is the comparative efficacy of unilateral instrumentation compared with bilateral instrumentation in spine surgery? (2) What is the safety of unilateral instrumentation compared with bilateral instrumentation in spine surgery? Methods Electronic databases and reference lists of key articles were searched up to September 30, 2014, to identify studies reporting the comparative efficacy and safety of unilateral versus bilateral instrumentation in spine surgery. Studies including recombinant human bone morphogenetic protein 2 as adjunct therapy and those with follow-up of less than 2 years were excluded. Results Ten randomized controlled trials met the inclusion criteria: five compared unilateral with bilateral instrumentation using open transforaminal or posterior lumbar interbody fusion (TLIF/PLIF), one used open posterolateral fusion, and four used minimally invasive TLIF/PLIF. There were no significant differences between unilateral and bilateral screw instrumentation with respect to nonunion, low back or leg pain scores, Oswestry Disability Index, reoperation, or complications. Conclusions The existing literature does not identify significant differences in clinical outcomes, union rates, and complications when unilateral instrumentation is used for degenerative pathologic conditions in the lumbar spine. The majority of published reports involve single-level lumbar unilateral instrumentation.

Clinical outcomes and sagittal alignment of single-level unilateral instrumented transforaminal lumbar interbody fusion with a 4 to 5-year follow-up

PURPOSE

A retrospective study was designed to evaluate clinical outcomes and sagittal alignment following single-level unilateral instrumented transforaminal lumbar interbody fusion (TLIF).

METHODS

From November 2008 to December 2010, a total of 139 patients, who suffered from single-level lumbar degenerative disease, were included in this study. Forty-seven males and seventy-two females with a mean age of 57.3 years were enrolled. The average follow-up period was 51.7 months with a range of 41-66 months. The follow-up rate was 85.6 %. Thirty-one patients had diagnosis of discogenic low back pain, ten had recurrent disk herniation, thirty-four had spinal stenosis, and fourty-four had spondylolisthesis. Clinical outcomes were evaluated using the Oswestry disability index (ODI), visual analog scale (VAS) and Japanese Orthopedic Association. Operating time, blood loss, length of stay, and complications were also evaluated. The sagittal alignment and fusion status were assessed by X-ray and three-dimensional computed tomography.

RESULTS

The average operating time was 92.1 ± 27.5 min, the average blood loss was 135.1 ± 113.5 ml, and the average length of stay was 12.0 ± 2.9 days. The overall complication rate was 13.4 %, and the fusion rate was 82.4 %. The postoperative clinical outcomes and sagittal alignment were significantly different from the preoperative values. The final lumbar lordosis angle and segment lordosis angle were associated with back pain VAS and ODI scores, respectively.

CONCLUSION

Unilateral instrumented TLIF is a safe and effective treatment option for single-level lumbar degenerative disease, and is less invasive, yields good outcomes and has a low complication rate. In addition, the procedure has the potential to partly restore sagittal alignment.

Novel pedicle screw and plate system provides superior stability in unilateral fixation for minimally invasive transforaminal lumbar interbody fusion: an in vitro biomechanical study

Purpose

This study aims to compare the biomechanical properties of the novel pedicle screw and plate system with the traditional rod system in asymmetrical posterior stabilization for minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). We compared the immediate stabilizing effects of fusion segment and the strain distribution on the vertebral body.

Methods

Seven fresh calf lumbar spines (L3-L6) were tested. Flexion/extension, lateral bending, and axial rotation were induced by pure moments of ± 5.0 Nm and the range of motion (ROM) was recorded. Strain gauges were instrumented at L4 and L5 vertebral body to record the strain distribution under flexion and lateral bending (LB). After intact kinematic analysis, a right sided TLIF was performed at L4-L5. Then each specimen was tested for the following constructs: unilateral pedicle screw and rod (UR); unilateral pedicle screw and plate (UP); UR and transfacet pedicle screw (TFS); UP and TFS; UP and UR.

Results

All instrumented constructs significantly reduced ROM in all motion compared with the intact specimen, except the UR construct in axial rotation. Unilateral fixation (UR or UP) reduced ROM less compared with the bilateral fixation (UP/UR+TFS, UP+UR). The plate system resulted in more reduction in ROM compared with the rod system, especially in axial rotation. UP construct provided more stability in axial rotation compared with UR construct. The strain distribution on the left and right side of L4 vertebral body was significantly different from UR and UR+TFS construct under flexion motion. The strain distribution on L4 vertebral body was significantly influenced by different fixation constructs.

Conclusions

The novel plate could provide sufficient segmental stability in axial rotation. The UR construct exhibits weak stability and asymmetrical strain distribution in fusion segment, while the UP construct is a good alternative choice for unilateral posterior fixation of MI-TLIF.

Unilateral versus bilateral pedicle screw fixation for degenerative lumbar diseases: a meta-analysis of 10 randomized controlled trials

Background

The common and effective treatment for degenerative lumbar diseases is lumbar spinal fusion. Controversy still exists on the choice for instrumentation with spinal fusion procedures. Therefore, we conducted this meta-analysis exclusively of RCTs to compare the clinical outcomes of patients receiving bilateral versus unilateral pedicle screw fixation (PSF).

Material/Methods

After systematic review of published and unpublished literature, a meta-analysis was conducted to compare the 2 treatment strategies. The methodological quality of the literature was assessed using the PEDro critical appraisal tool.

Results

Data synthesis showed less blood loss (P<0.001) and shorter operative time (P<0.001) in patients receiving unilateral PSF compared to bilateral PSF. However, there was no significant difference in fusion rates and functional outcomes between the 2 groups.

Conclusions

The meta-analysis indicated no significant difference in fusion rates and functional outcomes between the 2 treatment procedures, but unilateral PS fixation reduced blood loss and operative time.

Unilateral versus bilateral pedicle screw fixation of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF): a meta-analysis of randomized controlled trials

Background

A few studies focused on unilateral or bilateral pedicle screw (PS) fixation of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) to treat lumbar degenerative diseases have been published. There is still debate over whether one method is superior to another. A systematic review and meta-analysis of randomized controlled trials (RCT) was performed to compare the efficacy of the two methods.

Methods

We searched the established electronic literature databases of MEDLINE, EMBASE, Web of Science and the Cochrane Central Register of Controlled Trials databases for RCTs comparing the unilateral with bilateral pedicle screw fixation of MIS-TLIF. Pooled mean differences (MD) and odds ratios (OR) and with 95% CIs were calculated for the outcomes.

Results

Three RCTs were identified and analyzed. The results showed that there is no significant difference between the two methods in terms of postoperative VAS-BP score (WMD = -0.09; 95% CI: -0.69 to 0.51; P =0.78), ODI (WMD, -0.09; 95% CI -5.85 to 5.67; P =0.98), fusion rate (OR = 2.99; 95% CI 0.55 to 16.38; P = 0.21) or complication rate (OR = 1.61, 95% CI: 0.49 to 5.37; P =0.43). Unilateral pedicle screw fixation was associated with less blood loss (WMD = -87.83; 95% CI: -160.70 to -14.96; P =0.02).

Conclusions

The existing evidence indicate that no superiority exists between the two fixation methods of MIS-TLIF in terms of functional outcome, fusion rate and complication rate, in spite of that unilateral pedicle screw fixation can achieve less blood loss than bilateral fixation.

A meta-analysis of unilateral versus bilateral pedicle screw fixation in minimally invasive lumbar interbody fusion

STUDY DESIGN

Meta-analysis.

BACKGROUND

Bilateral pedicle screw fixation (PS) after lumbar interbody fusion is a widely accepted method of managing various spinal diseases. Recently, unilateral PS fixation has been reported as effective as bilateral PS fixation. This meta-analysis aimed to comparatively assess the efficacy and safety of unilateral PS fixation and bilateral PS fixation in the minimally invasive (MIS) lumbar interbody fusion for one-level degenerative lumbar spine disease.

METHODS

MEDLINE/PubMed, EMBASE, BIOSIS Previews, and Cochrane Library were searched through March 30, 2014. Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) on unilateral versus bilateral PS fixation in MIS lumbar interbody fusion that met the inclusion criteria and the methodological quality standard were retrieved and reviewed. Data on participant characteristics, interventions, follow-up period, and outcomes were extracted from the included studies and analyzed by Review Manager 5.2.

RESULTS

Six studies (5 RCTs and 1 CCT) involving 298 patients were selected. There were no significant differences between unilateral and bilateral PS fixation procedures in fusion rate, complications, visual analogue score (VAS) for leg pain, VAS for back pain, Oswestry disability index (ODI). Both fixation procedures had similar length of hospital stay (MD = 0.38, 95% CI = -0.83 to 1.58; P = 0.54). In contrast, bilateral PS fixation was associated with significantly more intra-operative blood loss (P = 0.002) and significantly longer operation time (P = 0.02) as compared with unilateral PS fixation.

CONCLUSIONS

Unilateral PS fixation appears as effective and safe as bilateral PS fixation in MIS lumbar interbody fusion but requires less operative time and causes less blood loss, thus offering a simple alternative approach for one-level lumbar degenerative disease.

Minimally invasive transforaminal lumbar interbody fusion with unilateral pedicle screw fixation: comparison between primary and revision surgery

Minimally invasive surgery with a transforaminal lumbar interbody fusion (MIS TLIF) is an important minimally invasive fusion technique for the lumbar spine. Lumbar spine reoperation is challenging and is thought to have greater complication risks. The purpose of this study was to compare MIS TLIF with unilateral screw fixation perioperative results between primary and revision surgeries. This was a prospective study that included 46 patients who underwent MIS TLIF with unilateral pedicle screw. The patients were divided into two groups, primary and revision MIS TLIF, to compare perioperative results and complications. The two groups were similar in age, sex, and level of operation, and were not significantly different in the length of follow-up or clinical results. Although dural tears were more common with the revision group (primary 1; revision 4), operation time, blood loss, total perioperative complication, and fusion rates were not significantly different between the two groups. Both groups showed substantial improvements in VAS and ODI scores one year after surgical treatment. Revision MIS TLIF performed by an experienced surgeon does not necessarily increase the risk of perioperative complication compared with primary surgery. MIS TLIF with unilateral pedicle screw fixation is a valuable option for revision lumbar surgery.