Correction of Spondylolisthesis by Lateral Lumbar Interbody Fusion Compared with Transforaminal Lumbar Interbody Fusion at L4-5

Anatomical Reduction of Spondylolisthesis Through Lateral Lumbar Interbody Fusion With Percutaneous Pedicle Screw Fixation: An Intraoperative Technical Note

BACKGROUND

Surgical management of lumbar spondylolisthesis requires neural decompression, stabilization, and alignment restoration. Minimally invasive spine approaches offer a wide variety of advantages for spondylolisthesis management. This intraoperative note describes the treatment of L4-L5 lumbar spondylolisthesis with lateral lumbar interbody fusion (LLIF) and percutaneous pedicle screw fixation (PSF).

METHODS

The surgical technique for treating L4-L5 lumbar spondylolisthesis using a minimally invasive approach with LLIF and percutaneous PSF is described. This operative technique is illustrated with figures, and an intraoperative case example of its application is described.

RESULTS

LLIF with percutaneous PSF can be a safe, effective, and reliable option for treating lumbar spondylolisthesis when applied with appropriate surgical technique in a selected patient population. This technique is a valuable addition to the range of available spine surgical options.

CONCLUSIONS

LLIF with percutaneous PSF can be an effective technique for treating lumbar L4-L5 spondylolisthesis.

Endplate weakening during cage bed preparation significantly reduces endplate load capacity

PURPOSE

To analyze the effect of endplate weakness prior to PLIF or TLIF cage implantation and compare it to the opposite intact endplate of the same vertebral body. In addition, the influence of bone quality on endplate resistance was investigated.

METHODS

Twenty-two human lumbar vertebrae were tested in a ramp-to-failure test. One endplate of each vertebral body was tested intact and the other after weakening with a rasp (over an area of 200 mm2). Either a TLIF or PLIF cage was then placed and the compression load was applied across the cage until failure of the endplate. Failure was defined as the first local maximum of the force measurement. Bone quality was assessed by determining the Hounsfield units (HU) on CT images.

RESULTS

With an intact endplate and a TLIF cage, the median force to failure was 1276.3N (693.1-1980.6N). Endplate weakening reduced axial endplate resistance to failure by 15% (0-23%). With an intact endplate and a PLIF cage, the median force to failure was 1057.2N (701.2-1735.5N). Endplate weakening reduced axial endplate resistance to failure by 36.6% (7-47.9%). Bone quality correlated linearly with the force at which endplate failure occurred. Intact and weakened endplates showed a strong positive correlation: intact-TLIF: r = 0.964, slope of the regression line (slope) = 11.8, p < 0.001; intact-PLIF: r = 0.909, slope = 11.2, p = 5.5E-05; weakened-TLIF: r = 0.973, slope = 12.5, p < 0.001; weakened-PLIF: r = 0.836, slope = 6, p = 0.003.

CONCLUSION

Weakening of the endplate during cage bed preparation significantly reduces the resistance of the endplate to subsidence to failure: endplate load capacity is reduced by 15% with TLIF and 37% with PLIF. Bone quality correlates with the force at which endplate failure occurs.

Load distribution on intervertebral cages with and without posterior instrumentation

BACKGROUND CONTEXT

Posterior and transforaminal lumbar interbody fusion (PLIF, TLIF) are well-established procedures for spinal fusion. However, little is known about load sharing between cage, dorsal construct, and biological tissue within the instrumented lumbar spine.

PURPOSE

The aim of this study was to quantify the forces acting on cages under axial compression force with and without posterior instrumentation.

STUDY DESIGN

Biomechanical cadaveric study.

METHODS

Ten lumbar spinal segments were tested under uniaxial compression using load cell instrumented intervertebral cages. The force was increased in 100N increments to 1000N or a force greater than 500N on one load cell. Each specimen was tested after unilateral PLIF (uPLIF), bilateral PLIF (bPLIF) and TLIF each with/without posterior instrumentation. Dorsal instrumentation was performed with 55N of compression per side.

RESULTS

Cage insertion resulted in median cage preloads of 16N, 29N and 35N for uPLIF, bPLIF, and TLIF. The addition of compressed dorsal instrumentation increased the median preload to 224N, 328N, and 317N, respectively. With posterior instrumentation, the percentage of the external load acting on the intervertebral cage was less than 25% at 100N (uPLIF: 14.2%; bPLIF: 16%; TLIF: 11%), less than 45% at 500N (uPLIF: 31.8%; bPLIF: 41.1%; TLIF: 37.9%) and less than 50% at 1000N (uPLIF: 40.3%; bPLIF: 49.7%; TLIF: 43.4%). Without posterior instrumentation, the percentage of external load on the cages was significantly higher with values above 50% at 100N (uPLIF: 55.6%; bPLIF: 75.5%; TLIF: 66.8%), 500N (uPLIF: 71.7%; bPLIF: 79.2%; TLIF: 65.4%), and 1000N external load (uPLIF: 73%; bPLIF: 80.5%; TLIF: 66.1%). For absolute loads, preloads and external loads must be added together.

CONCLUSIONS

Without posterior instrumentation, the intervertebral cages absorb more than 50% of the axial load and the load distribution is largely independent of the loading amplitude. With posterior instrumentation, the external load acting on the cages is significantly lower and the load distribution becomes load amplitude dependent, with a higher proportion of the load transferred by the cages at high loads. The bPLIF cages tend to absorb more force than the other two cage configurations.

CLINICAL SIGNIFICANCE

Cage instrumentation allows some of the compression force to be transmitted through the cage to the screws below, better distributing and reducing the overall force on the pedicle screws at the end of the construct and on the rods.

Radiological and Clinical Outcomes comparing 2-level MIS Lateral and MIS Transforaminal Lumbar Interbody Fusion in Degenerative Lumbar Spinal Stenosis

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVES

To compare early postoperative radiological and clinical outcomes between 2-level minimally invasive (MIS) trans-psoas lateral lumbar interbody fusion (LLIF) and MIS transforaminal lumbar interbody fusion (TLIF) for degenerative lumbar spinal stenosis.

METHODS

Fifty three consecutive patients undergoing 2-level lumbar interbody fusion from L3-L5 for degenerative lumbar spinal stenosis were enrolled. Twenty four patients underwent LLIF and 29 underwent TLIF.

RESULTS

Operative time and length of stay were similar between LLIF and TLIF (272.8 ± 82.4 vs 256.1 ± 59.4 minutes; 5.5 ± 2.8 vs 4.7 ± 3.3 days, P > .05), whereas blood loss was lower for LLIF (229.0 ± 125.6 vs 302.4 ± 97.1mls, P = .026). Neurological deficits were more common in LLIF (9 vs 3, P = .025), whereas persistent deficits were rare for both (1 vs 1, P = 1). For both groups, all patient reported outcomes visual analogue scale (VAS back pain, VAS leg pain, ODI, SF-36 physical) improved from preoperative to 2-years postoperative (P < .05), with both groups showing no significant differences in extent of improvement for any outcome. Lateral lumbar interbody fusion demonstrated superior restoration of disc height (L3-L4: 4.1 ± 2.4 vs 1.2 ± 1.9 mm, P < .001; L4-L5: 4.6 ± 2.4 vs .8 ± 2.8 mm, P < .001), foraminal height (FH) (L3-L4: 3.5 ± 3.6 vs 1.0 ± 3.6 mm, P = .014; L4-L5: 3.0 ± 3.5 vs -.1 ± 4.4 mm, P = .0080), segmental lordosis (4.1 ± 6.4 vs -2.1 ± 8.1°, P = .005), lumbar lordosis (LL) (4.1 ± 7.0 vs -2.3 ± 12.6°, P = .026) and pelvic incidence-lumbar lordosis (PI-LL) mismatch (-4.1 ± 7.0 vs 2.3 ± 12.6°, P = .019) at 2-years follow-up.

CONCLUSION

The superior radiological outcomes demonstrated by 2-level trans-psoas LLIF did not translate into difference in clinical outcomes compared to 2-level TLIF at the 2-years follow-up, suggesting both approaches are reasonable for 2-level lumbar interbody fusion in degenerative lumbar spinal stenosis.

Effect of Lateral Surgery Compared with Posterior Surgery on Lumbar Degenerative Disease: A Meta-Analysis of 41 Cohort Studies

OBJECTIVE

The purpose of this study was to compare the efficacy of the lateral approach and posterior approach in the treatment of lumbar degenerative diseases.

METHODS

Through a systematic search of relevant articles published on or before July 20, 2023, in the Embase, PubMed, and Cochrane libraries, the 2 authors independently extracted data and used the Newcastle‒Ottawa scale to evaluate the quality of the included studies. Using Stata16 software, the continuous variables were presented as the standard mean deviation, and the bipartite variables were analyzed using the pooled odds ratio with 95% confidence interval.

RESULTS

A total of 13,892 articles were screened and 10,908 studies were identified after deleting duplicates, of which 41 met the criteria and were included in the meta-analysis. The meta-analysis showed that the lateral approach was superior to the posterior approach in reducing blood loss, operation time, and hospital stay. At the same time, compared with the posterior approach, the lateral approach has more advantages in the long-term Japanese Orthopaedic Association score and Oswestry Disability Index score, adjusting mid- and long-term LL and short- and long-term disc height.

CONCLUSIONS

Lateral and posterior surgery have similar clinical effects in the treatment of lumbar degenerative diseases and can significantly reduce pain and improve postoperative SL. At the same time, the lateral approach has more advantages in improving long-term quality of life, reducing the long-term disability index, adjusting mid- and long-term LL and short- and long-term disc height.

Minimally Invasive Approach for Degenerative Spondylolisthesis: Lateral Single-Position Surgery with Intraoperative Computed Tomography Navigation and Fluoroscopy: A Technical Note

OBJECTIVE

Degenerative spondylolisthesis (DS) is a prevalent condition that leads to low back pain and neurological symptoms. This technical note presents a novel surgical strategy for treating DS using lateral single-position surgery (SPS) in combination with intraoperative computed tomography navigation and fluoroscopy.

METHODS

Fifteen patients (5 males and 10 females, mean age 70.2 years) diagnosed with DS with a slip of 5 mm or more underwent lateral lumbar interbody fusion (LLIF) with percutaneous pedicle screw (PPS) fixation using this technique. The procedure involved slip reduction using an upside PPS and rod fixation, followed by LLIF performed in the same lateral position. The term "upside PPS" refers to a PPS that is inserted on the ceiling side of the patient's surgical field. Preoperative and postoperative radiographic assessments were conducted to evaluate the effectiveness of the lateral SPS.

RESULTS

The results demonstrated significant improvements in various parameters, including spondylolisthesis reduction, segmental lordosis, disc height, and spinal canal dimensions. The lateral-SPS procedure exhibited several advantages over traditional flip LLIF approaches for slip reduction. Additionally, the technique provided accurate intraoperative navigation guidance through computed tomography imaging, ensuring precise implant placement and slip reduction.

CONCLUSIONS

Combining LLIF and PPS fixation in a single procedure presents a precise, efficient approach for DS treatment, minimizing repositioning needs. This technique enables effective lumbar reconstruction, restoration of spinal stability, and improved patient outcomes. Although further investigation is warranted, lateral SPS surgery may hold promise as an innovative solution for managing DS by reducing surgical invasiveness and optimizing surgical efficiency.

Lateral versus posterior approaches to treat degenerative lumbar pathologies-systematic review and meta-analysis of recent literature

INTRODUCTION

The lateral lumbar interbody fusion arose as a revolutionary approach to treating several spinal pathologies because the techniques were able to promote indirect decompression and lordosis restoration through a minimally invasive approach allowing for reduced blood loss and early recovery for patients. However, it is still not clear how the technique compares to other established approaches for treating spinal degenerative diseases, such as TLIF, PLIF, and PLF.

MATERIAL AND METHODS

This is a systematic review and meta-analysis of articles published in the last 10 years comparing lateral approaches to posterior techniques. The authors included articles that compared the LLIF technique to one or more posterior approaches, treating only degenerative pathologies, and containing at least one of the key outcomes of the study. Exclusion articles that were not original and the ones that the authors could not obtain the full text; also articles without the possibility to calculate the standard deviation or mean were excluded. For count variables, the odds ratio was used, and for continuous variables, the standard means difference (SMD) was used, and the choice between random or fixed-effects model was made depending on the presence or not of significant (p < 0.05) heterogeneity in the sample.

RESULTS

Twenty-four articles were included in the quantitative review. As for the intra-/perioperative variables, the lateral approaches showed a significant reduction in blood loss (SMD-1.56, p < 0.001) and similar operative time (SMD =  - 0.33, p = 0.24). Moreover, the use of the lateral approaches showed a tendency to lead to reduced hospitalization days (SMD =  - 0.15, p = 0.09), with significantly reduced odds ratios of complications (0.53, p = 0.01). As for the clinical outcomes, both approaches showed similar improvement both at improvement as for the last follow-up value, either in ODI or in VAS-BP. Finally, when analyzing the changes in segmental lordosis and lumbar lordosis, the lateral technique promoted significantly higher correction in both outcomes (p < 0.05).

CONCLUSION

Lateral approaches can promote significant radiological correction and similar clinical improvement while reducing surgical blood loss and postoperative complications.

The Feasibility of 3D Intraoperative Navigation in Lateral Lumbar Interbody Fusion: Perioperative Outcomes, Accuracy of Cage Placement and Radiation Exposure

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To evaluate perioperative outcomes, accuracy of cage placement and radiation exposure in lateral lumbar interbody fusion (LLIF) using 3D intraoperative navigation (ION), compared to conventional 2D fluoroscopy only.

METHODS

The perioperative outcomes and accuracy of cage placement were examined in all patients who underwent LLIF using ION (ION group) or fluoroscopy only (non-ION group) by a single surgeon. The radiation exposure was examined in patients who underwent stand-alone LLIF.

RESULTS

A total of 87 patients with 154 levels (ION 49 patients with 79 levels/ non-ION 38 patients with 75 levels) were included. There were no significant differences in operative time (ION 143.5 min vs. non-ION 126.0 min, P = .406), time from induction end to surgery start (ION 31.0 min vs. non-ION 31.0 min, P = .761), estimated blood loss (ION 37.5 ml vs. non-ION 50.0 ml, P = .351), perioperative complications (ION 16.3% vs. non-ION 7.9%, P = .335) and length of stay (ION 50.6 hours vs. non-ION 41.7 hours, P = .841). No significant difference was found in the accuracy of cage placement (P = .279). ION did not significantly increase total radiation dose (ION 51.0 mGy vs. non-ION 47.4 mGy, P = .237) and tended to reduce radiation dose during the procedure (ION 32.2 mGy vs. non-ION 47.4 mGy, P = .932).

CONCLUSIONS

The perioperative outcomes, accuracy of cage placement and radiation exposure in LLIF using ION were comparable to those using fluoroscopy only. The use of ION in LLIF was feasible, safe and accurate and may reduce radiation dose to the surgeon and surgical team.

Is Indirect Decompression and Fusion More Effective than Direct Decompression and Fusion for Treating Degenerative Lumbar Spinal Stenosis With Instability? A Systematic Review and meta-Analysis

Study design: Systematic Review and Meta-analysis.Objective: Surgical alternatives to treat lumbar spinal stenosis and instability include indirect (ALIF, OLIF, and LLIF) and direct (TLIF or posterior lumbar interbody fusion) decompression and fusion interventions. Although both approaches have proven to be effective in reducing symptoms, it is unknown if there is any difference in effectiveness between them. In this systematic review and meta-analysis, we aimed to evaluate postoperative pain and disability in patients treated whit indirect vs direct decompression and fusion approaches.Methods: We conducted a systematic review of the literature consulting several databases and identified studies that enrolled patients diagnosed with degenerative lumbar spinal stenosis and instability treated with indirect or direct decompression and fusion techniques. Our primary endpoints were the visual analogue scale, Oswestry Disability Index, and the Japanese Orthopedics Association Back Pain Evaluation Questionnaire 1 year after the procedure. Secondary outcomes included complication rate, blood loss, and surgical time.Results: Nine retrospective and comparative studies were included enrolling a total of 1004 participants. Both surgical strategies had satisfactory clinical outcomes with no significant difference at 1 year. Although the complication rate was similar for both groups, the profile of the adverse events was different. In addition, patients treated with indirect decompression and fusion had significantly less blood loss and operative times.Conclusions: Indirect and direct decompression and fusion techniques are similarly effective in treating patients with lumbar spinal stenosis and instability. The ID group had significantly lower intraoperative blood loss and surgical time values.

Subsidence of Spinal Fusion Cages: A Systematic Review

BACKGROUND

Although many research studies investigating subsidence of intervertebral fusion cages have been published, to our knowledge, no study has comprehensively compared cage subsidence among all lumbar intervertebral fusion (LIF) techniques. This study aimed to review the literature reporting evidence of cage subsidence linked to LIF. The amount of subsidence was compared and associated with the procedures and corresponding implants used, and the effect of cage subsidence on clinical outcomes was investigated.

METHODS

For this systematic review, the MEDLINE and PubMed databases were used to identify relevant studies. Search terms included lumbar, lumbar vertebrae, lumbar spine, cage, spinal fusion, prosthesis, prosthesis implantation, implantation, implants, interbody, spacer, and subsidence. Studies included in this review were those having more than 10 patients and reporting the amount of subsidence observed using computed tomography or x-ray imaging after surgery and at follow-up visits after a minimum of 6 weeks postsurgery. Data and scale definitions related to subsidence were extracted from articles for comparison of subsidence prevalence between the 5 LIF surgical procedures.

RESULTS

Forty articles were identified for inclusion. The review included data from 390 anterior lumbar intervertebral fusions (ALIFs), 2130 lateral lumbar intervertebral fusions (LLIFs), 560 posterior lumbar intervertebral fusions (PLIFs), 245 oblique lumbar intervertebral fusions (OLIFs), and 1634 transverse lumbar intervertebral fusions (TLIFs) for a total of 4959 patients who underwent LIF surgery. The minimum and maximum percentages of the number of patients having subsidence for each procedure in the included studies were as follows: ALIF stand-alone, 6% and 23.1%; LLIF stand-alone, 8.7% and 39.6%; LLIF with posterior fixation, 3.3% and 20.7%; OLIF with posterior fixation, 4.4% and 36.9%; PLIF with posterior fixation, 7.4% and 31.8%; and TLIF, 0.0% and 51.2%.

CONCLUSIONS

The number of patients experiencing subsidence varied between studies within each fusion procedure. Our findings indicate that all 5 surgical methods are at risk of subsidence. Overall, ALIF without posterior fixation resulted in the lowest reported subsidence occurrence among the 5 surgical approaches. There is conflicting evidence on the association between subsidence and negative clinical outcomes.

CLINICAL RELEVANCE

This review defines and compares subsidence incidence between all LIF procedures and investigates the risk of symptomatic clinical outcomes.

LEVEL OF EVIDENCE: 4

Single-level TLIF Versus LLIF at L4-5: A Comparison of Patient-reported Outcomes and Recovery Ratios

INTRODUCTION

Both transforaminal lumbar interbody fusion (TLIF) and lateral lumbar interbody fusion (LLIF) are suitable for achievement of lumbar arthrodesis. Comparative studies have observed complications and outcomes without stratification by lumbar level. This study aims to assess patient-reported outcome measures (PROMs) and recovery in TLIF and LLIF at L4-5.

METHODS

Patients undergoing primary, elective, single-level, TLIF or LLIF procedures at L4-5 were grouped. Demographics, perioperative characteristics, and postoperative complication rates were collected. PROMs included Patient-Reported Outcome Measurement Information System Physical Function, visual analog scale (VAS) back and leg, Oswestry Disability Index, and 12-Item Short-Form Physical Component Summary, and Mental Component Summary and were collected at preoperative, 6-week, 12-week, 6-month, 1-year, and 2-year time points. Delta values and recovery ratios (RRs) were calculated for all PROMs at all time points. Demographics, perioperative characteristics, and postoperative complications were compared using chi-squared and Student t-test for categorical and continuous variables, respectively. Differences in mean PROMs, delta values, and RR at each time point were evaluated using unpaired Student's t-test.

RESULTS

Three hundred sixty TLIF and 46 LLIF patients were included. Most (54.3%) were men, mean age 56.3 years, and mean body mass index 30.8 kg/m2. Body mass index and insurance significantly differed (P ≤ 0.045, all). TLIF showed significantly greater mean operative time, length of stay, and postoperative narcotic consumption (P < 0.033, all) and greater postoperative nausea/vomiting (P = 0.004). No preoperative PROMs significantly differed. TLIF cohort had significantly greater VAS back at 6 months and VAS leg at 12 weeks and 6 months (P < 0.034, all). No mean delta PROMs or RRs significantly differed.

DISCUSSION

LLIF demonstrated significantly reduced length of stay, postoperative narcotic consumption, and postoperative nausea/vomiting and significantly improved VAS back at 6 months and VAS leg at 12 weeks and 6 months versus TLIF. Although 2-year PROMs and RRs did not significantly differ, our findings may suggest improved midterm follow-up pain scores for LLIF patients.

Importance of Surgical Order for Minimizing Vascular Injury During the L5-S1 Approach in Multilevel Oblique Lateral Interbody Fusion Surgery

Objective

In oblique lateral interbody fusion (OLIF) surgery at the L5-S1 level (OLIF51), anatomical complexity and the possibility of vascular injury during retraction of the common iliac vein (CIV) make the surgery challenging. We radiologically evaluated patients who underwent OLIF surgery to determine approaches that can make OLIF51 surgery easier during multilevel OLIF.

Methods

We retrospectively analyzed 275 consecutive patients who underwent OLIF surgery between September 2014 and December 2019. The distance between the left and right CIVs (dCIV) was measured using an axial image at the L5 lower endplate level, and the height of the iliocaval junction (hCIV) was measured from the L5 lower endplate to the iliocaval junction in the sagittal image. The sum of anterior disc height of each level (sADH) was calculated.

Results

Eighty-two patients (33 males and 49 females) were enrolled. The number of three- (L2-3-4-5), two- (L3-4-5), and one-level (L4-5) fusions was 13, 21, and 48, respectively. Changes between the pre- and postoperative sADH, dCIV, and hCIV values were 17.1±4.7, 7.7±3.5, and 13.1±4.7 mm in three-level fusion; 10.6±4.1, 5.6±3.7, and 7.0±3.1 in two-level fusion; and 4.3±2.5, 3.3±2.7, and 3.0±2.0 mm in one-level fusion, respectively. As the number of surgical levels increased, the changes in sADH, dCIV, and hCIV significantly increased.

Conclusions

The dCIV and hCIV values increased when the upper segment underwent surgery before OLIF51 during multilevel OLIF.

Comparison of Outcomes Between Single-level Lateral Lumbar Interbody Fusion and Transforaminal Lumbar Interbody Fusion: A Meta-analysis and Systematic Review

STUDY DESIGN

This is a meta-analysis and systematic review of the available literature.

OBJECTIVE

This study aims to compare the clinical and radiologic outcomes of single-level lateral lumbar interbody fusion (LLIF) with single-level transforaminal lumbar interbody fusion (TLIF).

SUMMARY OF BACKGROUND DATA

In the treatment of adult spinal deformity, LLIF allows interbody fusion while avoiding complications associated with an anterior or transforaminal approach, although the clinical outcomes of LLIF compared with other approaches have not been well established.

METHODS

We searched PubMed, Embase, and Scopus for 385 unique studies. On the basis of our exclusion criteria, 8 studies remained for our systematic review. Data were analyzed using Review Manager 5.3 using Mantel-Haenszel statistics and random effect models. This study identified self-reported Visual Analog Scale (VAS), Oswestry Disability Index, length of stay, blood loss, complication rate, and radiologic parameters (disk height, lumbar lordosis, segmental lordosis).

RESULTS

Our meta-analysis showed that LLIF contributed to decreased blood loss [mean difference (MD)=-67.62 mL, 95% confidence interval (CI): -104 to -30.90, P<0.001], superior restoration of segmental lordosis (MD=1.91 degrees, 95% CI: 0.71-3.10, P=0.002), lumbar lordosis (MD=1.95 degrees, 95% CI: 0.15-3.74, P=0.03), and disk height (MD=2.18 mm, 95% CI: 1.18-3.17, P<0.001) when compared with TLIF. However, current data suggests no significant difference in clinical outcomes between LLIF and TLIF based on overall complication rates (P=0.22), length of hospital stay (P=0.65), postoperative Oswestry Disability Index (P=0.13), postoperative VAS Back Pain (P=0.47) and VAS Leg Pain (P=0.16).

CONCLUSIONS

LLIF is an increasingly popular option for single-level anterior column reconstruction. When compared with single-level TLIF, single-level LLIF is associated with greater changes in lumbar lordosis and disk height. The single-level LLIF is a viable alternative to TLIF, demonstrating comparable clinical outcomes and better restoration of spinopelvic parameters.

LEVEL OF EVIDENCE

Level III.

Incidence and risk factors of lateral cage migration occurred after the first-stage lateral lumbar interbody fusion surgery

BACKGROUND

Lateral lumbar interbody fusion (LLIF) is a novel, minimally invasive technique for the surgical treatment of lumbar diseases. The aim of this study was to identify the incidence and risk factors of lateral cage migration (LCM) occurred after the first-stage LLIF.

HYPOTHESIS

The hypothesis was that LCM occurred after the first-stage LLIF was associated with some demographic characteristics, surgical variables and radiographic parameters.

PATIENTS AND METHODS

Between June 2016 and August 2020, 335 patients (901 levels) underwent staged LLIF were retrospectively reviewed. Patients were classified into LCM and non-LCM group based on the experience of LCM before the second-stage posterior instrumentation. 100 patients in non-LCM were randomly sampled as a control group. Incidence of LCM was determined; demographic characteristics, surgical variables and radiographic parameters associated with LCM were compared between the LCM and control group. Univariate analyses and multivariable logistic regression analysis were used to identify the risk factors.

RESULTS

LCM occurred after the first-stage LLIF was found in 19 (5.7%) patients. Bony endplate injury (OR, 106.255; 95% CI, 1.265-8924.765; p=0.039) and greater preoperative range of motion (ROM) (OR, 2.083, 95% CI, 1.068-4.066, p=0.031) were high risk factors for LCM. LCM occurred mainly 3 days later after the first-stage LLIF, while 4 cases experienced severe neural symptoms, intolerable low back pain and finally underwent reoperation.

DISCUSSION

LCM occurred after the first-stage LLIF was significantly associated with bony endplate injury and greater preoperative ROM. Second-stage posterior fixation should be performed as soon as possible or a supplement lateral fixation/self-locking cage should be used in high-risk patients.

LEVEL OF EVIDENCE

IV.

Comparison of Minimally Invasive Lateral Lumbar Interbody Fusion, Minimally Invasive Lateral Lumbar Interbody Fusion, and Open Posterior Lumbar Interbody Fusion in the Treatment of Single-Level Spondylolisthesis of L4-L5

OBJECTIVE

To compare the outcomes of minimally invasive lateral lumbar interbody fusion (LLIF) with minimally invasive transforaminal lumbar interbody fusion (TLIF) and conventional open posterior lumbar interbody fusion (PLIF) for treating single-level spondylolisthesis at L4-L5.

METHODS

The patients underwent minimally invasive LLIF (n = 18), minimally invasive TLIF (n = 17), and conventional open PLIF (n = 20) for spondylolisthesis at L4-L5. Reduction of slippage, improvement in segmental lordosis, and restoration of foraminal height were measured. Perioperative parameters such as blood loss and operation time and clinical outcomes such as visual analog scale score and Oswestry Disability Index were compared.

RESULTS

Compared with the open PLIF group, the minimally invasive LLIF group showed greater restoration of mean foraminal height, significantly smaller mean intraoperative estimated blood loss, and less mean hemoglobin reduction on the third day postoperatively. Compared with the minimally invasive TLIF group, the minimally invasive LLIF group showed greater restoration of mean segmental lordosis. The minimally invasive LLIF group showed a significantly shorter mean time to start walking after surgery compared with the conventional open PLIF and minimally invasive TLIF groups. However, compared with the minimally invasive TLIF group, the minimally invasive LLIF group showed a significantly longer mean operating time. Clinical outcomes were not statistically different among the 3 groups.

CONCLUSIONS

In the treatment of spondylolisthesis of L4-L5, minimally invasive LLIF provided an effective surgical alternative to minimally invasive TLIF or conventional open PLIF, with the advantages of less blood loss, the faster start of postoperative walking, and comparable improvement in radiologic parameters.

Transforaminal Lumbar Interbody Fusion (TLIF) versus Oblique Lumbar Interbody Fusion (OLIF) in Interbody Fusion Technique for Degenerative Spondylolisthesis: A Systematic Review and Meta-Analysis

Preoperative pathology requiring fusion surgery has a great impact on postoperative outcomes. However, the previous clinical and meta-analysis studies did not control for the pathology. In this systematic review, the authors aimed to compare oblique lumbar interbody fusion (OLIF) with transforaminal interbody fusion (TLIF) as an interbody fusion technique in lumbar fusion surgery for patients with degenerative spondylolisthesis (DS). We systematically searched for relevant articles in the available databases. Among the 3022 articles, three studies were identified and met the inclusion criteria. In terms of radiological outcome, the amount of disc height restoration was greater in the OLIF group than in the TLIF group, but there was no significant difference between the two surgical techniques (p = 0.18). In the clinical outcomes, the pain improvement was not significantly different between the two surgical techniques. In terms of surgical outcomes, OLIF resulted in a shorter length of hospital stay and less blood loss than TLIF (p < 0.0001 and p = 0.02, respectively). The present meta-analysis indicated no significant difference in clinical, radiological outcomes, and surgical time between TLIF and OLIF for DS, but the lengths of hospital stay and blood loss were better in OLIF than TLIF. Though encouraging, these findings were based on low-quality evidence from a small number of retrospective studies that are prone to bias.

Is stand-alone lateral lumbar interbody fusion superior to instrumented lateral lumbar interbody fusion for the treatment of single-level, low-grade, lumbar spondylolisthesis?

BACKGROUND

The aim of this study was to compare surgical trauma and radiographic and clinical outcomes of stand-alone and instrumented lateral lumbar interbody fusion (LLIF) in the treatment of single-level low-grade lumbar spondylolisthesis.

METHODS

Ninety-five patients with single-level low-grade lumbar spondylolisthesis, who underwent stand-alone LLIF (stand-alone group, [n = 54]) or LLIF plus percutaneous posterior fixation (instrumented group, [n = 41]) were enrolled in this study. Operative time, intraoperative blood loss, serum C-reactive protein (CRP) and creatine kinase (CK) levels, the length of postoperative bed rest time, and hospital stay were compared between the 2 groups. Disc height, the percent of slip, segment lordosis, lumbar lordosis, the visual analog scale score, the Oswestry Disability Index and complications were also compared.

RESULTS

Operative and bed rest time were shorter, intraoperative blood loss was less, and postoperative CRP and CK levels were lower in the stand-alone group. During follow-up, 6 patients in stand-alone group underwent posterior fixation due to cage subsidence. Although satisfactory radiographic results were achieved in both groups, the maintenance of increased disc heights and segment lordosis was inferior in the stand-alone group at the final follow-up. Greater improvement in postoperative VAS scores and ODI were observed in the stand-alone group, although the rates of cage subsidence and revision were higher.

CONCLUSION

Stand-alone LLIF was superior to instrumented LLIF in terms of tissue trauma for the treatment of single-level low-grade lumbar spondylolisthesis. However, stand-alone LLIF was inferior in the maintenance of disc height and segment lordosis, and the occurrence of cage subsidence and revision.

Lateral lumbar interbody fusion after reduction using the percutaneous pedicle screw system in the lateral position for Meyerding grade II spondylolisthesis: a preliminary report of a new lumbar reconstruction strategy

BACKGROUND

Utilization of a cage with a large footprint in lateral lumbar interbody fusion (LLIF) for the treatment of spondylolisthesis leads to a high fusion rate and neurological improvement owing to the indirect decompression effect and excellent alignment correction. However, if an interbody space is too narrow for insertion of an LLIF cage for cases of spondylolisthesis of Meyerding grade II or higher, LLIF cannot be used. Therefore, we developed a novel strategy, LLIF after reduction by the percutaneous pedicle screw (PPS) insertion system in the lateral position (LIFARL), for surgeons to perform accurate and safe LLIF with PPS in patients with such pathology. This study aimed to introduce the new surgical strategy and to present preliminary clinical and radiological results of patients with spondylolisthesis of Meyerding grade II.

METHODS

Six consecutive patients (four men and two women; mean age, 72.7 years-old; mean follow-up period, 15.3 months) with L4 spondylolisthesis of Meyerding grade II were included. Regarding the surgical procedure, first, PPSs were inserted into the L4 and L5 vertebrae fluoroscopically, and both rods were placed in the lateral position. The L5 set screws were fixed tightly, and the L4 side of the rod was floated. Second, the L4 vertebra was reduced by fastening the L4 set screws so that they expanded the anteroposterior width of the interbody space. At that time, the L4 set screws were not fully tightened to the rods to prevent the endplate injury. Finally, the LLIF procedure was started. After inserting the cage, a compression force was added to the PPSs, and the L4 set screws were completely fastened.

RESULTS

The mean operative time was 183 min, and the mean blood loss was 90.8 mL. All cages were positioned properly. Visual analog scale score and Oswestry disability index improved postoperatively. Bone union was observed using computed tomography 12 months after surgery.

CONCLUSION

For cases with difficulty in LLIF cage insertion for Meyerding grade II spondylolisthesis due to the narrow anteroposterior width of interbody space, LIFARL is an option to achieve LLIF combined with posterior PPS accurately and safely.

TRIAL REGISTRATION

UMIN-Clinical Trials Registry, UMIN000040268, Registered 29 April 2020, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000045938.

Comparison of extreme lateral approach with posterior approach in the treatment of lumbar degenerative diseases: A meta-analysis of clinical and imaging findings

OBJECTIVE

To compare clinical and imaging findings between extreme lateral lumbar interbody fusion (XLIF) and posterior fusion (PF) via meta-analysis for the treatment of lumbar degenerative diseases.

METHODS

English papers reporting clinical and imaging findings for the treatment of lumbar degenerative diseases with XLIF and PF published electronically in the PubMed, Embase, Cochrane Library, and Web of Science databases from January 2006 to August 2019 were retrieved. Two authors independently extracted data and evaluated the quality of the included literature. Meta-analysis of outcome measures was performed using Stata 14 and RevMan 5.3 software.

RESULTS

This meta-analysis included 744 patients from nine studies, two of which were prospective studies, while the others were retrospective studies. The quality of each study was determined to be high. The meta-analysis showed no significant differences in the operative time, length of hospital stay, clinical effectiveness, and improvement in postoperative global sagittal alignment between two approaches (P > 0.05). However, XLIF was significantly better than PF in reducing intraoperative blood loss and recovery of local sagittal alignment (P < 0.05). Moreover, the high incidence of postoperative complications were detected in XLIF group (P < 0.05).

CONCLUSIONS

Both surgical approaches have equally promising clinical effectiveness for the treatment of lumbar degenerative diseases. Although XLIF can reduce intraoperative blood loss and obtain better postoperative local sagittal alignment than PF, the high incidence of postoperative complications should prompt us to consider why XLIF procedure is still being offered to our patients and how we can reduce these complications. In addition, any conclusions should be taken with caution because of the mix of prospective and retrospective studies, and the high heterogeneity and bias.