Development and Application of Oblique Lumbar Interbody Fusion

Oblique lumbar interbody fusion combined with anterolateral screw fixation and stress endplate augmentation for treating degenerative lumbar spondylolisthesis with osteoporosis

PURPOSE

To evaluate the outcomes of Oblique lumbar interbody fusion (OLIF)combined with anterolateral screw fixation (AF) and Stress Endplate Augmentation(SEA) versus OLIF-AF in the treatment of degenerative lumbar spondylolisthesis (DLS)with osteoporosis (OP).

METHODS

30 patients underwent OLIF-AF-SEA (SEA group) were matched with 30 patients received OLIF-AF (control group), in terms of sex, age, body mass index (BMI) and bone mineral density (BMD). Clinical outcomes including visual analog scale (VAS) score of the lower back pain (VAS-LBP), leg pain (VAS-LP), and Oswestry Disability Index (ODI) were evaluated at different postoperative intervals and comparedwith their preoperative counterparts. Radiographic outcomes such as disk height (DH), slip distance (SD), lumbar lordosis (LL), segmental lordosis (SL), cage subsidence (CS) rate and fusion rate were evaluated at different postoperative intervals and compared with their preoperative counterparts.

RESULTS

SEA group presented to be better at 3-month and 12-month follow-up, the VAS-LBP, VAS-LP and ODI scores of the SEA group were significantly lower than the control group (3-month SEA vs control: 2.30±0.70 vs 3.30±0.75, 2.03±0.72 vs 2.90±0.76,15.60±2.36 vs 23.23±3.07, respectively, all p<0.05. VAS-LBP and ODI 12-month SEA vs control: 1.27±0.74 vs 1.93±0.58, 12.20±1.88 vs 14.43±1.89,respectively, all p<0.05). At 24-month follow-up, both groups showed no difference in fusion rate (83.33% vs 90.00%, p=0.45), while SEA group showed a lower CS rate (13.33% vs 53.33%, p<0.05).

CONCLUSION

OLIF-AF-SEA was safe with no adverse effects and resulted in lower CS rate and better sagittal balance. OLIF-AF-SEA is a promising surgical method for treating patients with DLS-OP.

Efficacy and safety of navigation robot-assisted versus conventional oblique lateral lumbar interbody fusion with internal fixation in the treatment of lumbar degenerative diseases: A retrospective study

Effective internal fixation with pedicle screw is a key factor in the success of lumbar fusion with internal fixation. Whether navigation robots can improve the efficacy and safety of screw placement is controversial. Thirty-eight patients who underwent oblique lateral lumbar interbody fusion internal fixation from March 2022 to May 2023 were retrospectively analyzed, 16 cases in the navigational robot group and 22 cases in the fluoroscopy group. Using visual analog score (VAS) for the low back and lower limbs, Oswestry Disability Index to compare the clinical efficacy of the 2 groups; using perioperative indexes such as the duration of surgery, intraoperative blood loss, intraoperative fluoroscopy times, and postoperative hospital stay to compare the safety of the 2 groups; and using accuracy of pedicle screws (APS) and the facet joint violation (FJV) to compare the accuracy of the 2 groups. Postoperative follow-up at least 6 months, there was no statistically significant difference between the 2 groups in the baseline data (P > .05). The navigational robot group's VAS-back was significantly lower than the fluoroscopy group at 3 days postoperatively (P < .05). However, the differences between the 2 groups in VAS-back at 3 and 6 months postoperatively, and in VAS-leg and Oswestry Disability Index at 3 days, 3 months, and 6 months postoperatively were not significant (P > .05). Although duration of surgery in the navigational robot group was significantly longer than in the fluoroscopy group (P > .05), the intraoperative blood loss and the intraoperative fluoroscopy times were significantly lower than in the fluoroscopy group (P < .05). The difference in the PHS between the 2 groups was not significant (P > .05). The APS in the navigation robot group was significantly higher than in the fluoroscopy group, and the rate of FJV was significantly lower than in the fluoroscopy group (P < .05). Compared with the traditional fluoroscopic technique, navigation robot-assisted lumbar interbody fusion with internal fixation provides less postoperative low back pain in the short term, with less trauma, less bleeding, and lower radiation exposure, as well as better APS and lower FJV, resulting in better clinical efficacy and safety.

Rat Model of Neuropathic Pain Induced by Spinal Nerve Ligation: A New Approach via an Oblique Lateral Incision

Purpose

The spinal nerve ligation (SNL) model is a typical peripheral neuropathic pain model. During its construction, the removal of paraspinal muscles and transverse processes typically occurs, resulting in additional trauma that may potentially affect the pathophysiologic process of neuropathic pain. This study aimed to investigate the feasibility of establishing a more reliable SNL model using an oblique lateral approach.

Methods

36 adult male Sprague-Dawley rats were randomly divided into three groups: the traditional SNL (T-SNL) group, the new SNL (N-SNL) group (where the left L5 spinal nerve was ligated with a titanium clip via an oblique lateral approach), and the sham-operated (Sham) group. The operation time, Intraoperative bleeding, the number of rats that died, gait behavior, mechanical and cold pain threshold were recorded and measured. Stereology technology was used to calculate the number of microglia in spinal dorsal horn, and the Enzyme-linked immunosorbent assay (ELISA) technology was used to detect the expression of TNF-α and IL-1β in spinal cord as well as C-reactive protein (CRP) in serum in order to assess the effect of surgery on animal inflammation.

Results

Compared with the T-SNL group, operative time and intraoperative bleeding were significantly decreased in the N-SNL group. Within 14 days postoperation, one rat in the N-SNL group was died, two rats in the T-SNL group were died. Compared with the Sham group, the N-SNL group showed obvious spontaneous pain behavior, decreased the pain thresholds, the number of microglia and the expression of TNF-α and IL-1β were significantly increased, and there was no significant difference in these indexes compared with T-SNL group. There was no significant difference in serum CRP levels among the three groups.

Conclusion

This study suggests that the oblique lateral approach SNL model is a reliable NP model with the advantages of good reproducibility, accessibility, and low trauma.

New Axially Expandable Oblique Cage Designed for Anterior to Psoas (ATP) Approach: Indications-Surgical Technique and Clinical-Radiological Outcomes in Patients with Symptomatic Degenerative Disc Disease

Background: Standard oblique cages cannot cover endplates side-to-side, which is an important biomechanical factor for reducing the risk of cage subsidence and for restoring correct segmental lordosis. The aim of this study is to evaluate the radiological and clinical results of a new oblique lumbar interbody fusion (OLIF) axially expandable cage. Methods: This is a prospective observational case-control study. From March 2018 to June 2020, 28 consecutive patients with lumbar degenerative disease underwent an ATP approach, with the insertion of a new axially expandable cage, which was used as a stand-alone procedure or followed by posterior percutaneous pedicle fixation. Results: Twenty-eight patients in both groups met the inclusion criteria. The mean follow-up time was 31.2 months (range of 13-37). The clinical results were not significantly different, although in the control group, two major intraoperative complications were recorded, and slight improvements in ODI and SF-36 scores were observed in the study group. The radiological results showed a less frequent incidence of subsidence and a higher rate of fusion in the study group compared to controls. Conclusions: The axially expandable oblique cage for lumbar inter body fusion, specifically designed for the ATP approach, represents an innovation and a technical improvement. The insertion and the axial expansion technique are safe and easy. The large footprint could obtain solid and effective arthrodesis, potentially reducing the risk of subsidence.

Access to the Lumbosacral Spine: A Current View

The surgical approach to the lumbosacral spine has been the subject of experimental and scientific anatomical studies since the Hippocratic era. However, it was in the 20th century that, with the evolution of asepsis and antibiotic therapy, spine surgery began to evolve at breakneck speed, and the various possibilities of access roads became objects of development and discussion. As a result, pathologies of the lumbosacral spine can be accessed in different ways and positions, from the traditional posterior approach in the prone position to the anterior, oblique, lateral, and endoscopic approaches. The current article brings state-of-the-art access routes to the lumbosacral spine. This article objective is to elucidate the possibilities of accesses the lumbar spine for any purposes, as decompression, fusion, tumour resections, reconstruction or deformity correction, despites type of implants or implants positioning.

Comparison of the clinical outcomes of VBE-TLIF versus MIS-TLIF for single-level degenerative lumbar diseases

OBJECTIVE

This research aims to compare the clinical outcomes of VBE-TLIF and MIS-TLIF for the treatment of patients with single-level degenerative lumbar diseases.

METHODS

Ninety patients were enrolled in this study. The estimated blood loss, operation time, postoperative hospitalization days, time to functional exercise, amount of surgical drain and inflammatory index were recorded. The visual analog scale, Oswestry dysfunction index and modified MacNab criteria were used to assessed the patient's back and leg pain, functional status and clinical satisfaction rates.

RESULTS

The average operation time of the VBE-TLIF group was longer than that of the MIS-TLIF group. The time for functional exercise, length of hospital stay, estimated blood loss and amount of surgical drain in the VBE-TLIF group were relative shorter than those in the MIS-TLIF group. Additionally, the levels of CRP, neutrophil, IL-6 and CPK in the VBE-TLIF group were significantly lower than those in the MIS-TLIF group at postoperative days 1 and 3, respectively (P < 0.001). Patients undergoing VBE-TLIF had significantly lower back VAS scores than those in the MIS-TLIF group on postoperative days 1 and 3 (P < 0.001). No significant differences were found in the clinical satisfaction rates (95.83 vs. 95.24%, P = 0.458) or interbody fusion rate (97.92 vs. 95.24%, P = 0.730) between these two surgical procedures.

CONCLUSIONS

Both VBE-TLIF and MIS-TLIF are safe and effective surgical procedures for patients with lumbar diseases, but VBE-TLIF technique is a preferred surgical procedure with merits of reduced surgical trauma and quicker recovery.

Analysis of the Screw Accuracy and Postoperative Efficacy of Screw Placement in Single Position and Bipedal Position in Robot-Assisted Oblique Lumbar Interbody Fusion: Preliminary Results of Mazor X Stealth Usage

OBJECTIVE

Traditional manual OLIF combined with pedicle screw implantation has many problems of manual percutaneous screw implantation, such as high difficulty of screw placement, many fluoroscopies, long operation time, and many adjustments, resulting in greater trauma. The robot can perform various types of screw placement in the lateral recumbent position, which allows OLIF combined with posterior screw placement surgery to be completed in a single position. To compare the screw accuracy and initial postoperative results of oblique anterior lumbar fusion with robot-assisted screw placement in the lateral position and screw placement in the prone position for the treatment of lumbar spondylolisthesis.

METHODS

From May to June 2022, 45 patients with single-segment lumbar spondylolisthesis underwent Mazor X-assisted oblique lumbar fusion in one position and Renaissance-assisted surgery in two different positions, and screw accuracy was assessed on computed tomography scans according to a modified Gertzbein-Robbins classification. Patients were divided into a single position group and a bipedal position group (the lateral position for complete oblique lumbar fusion and then changed to the prone position for posterior screw placement), and the perioperative parameters, including operative time, number of fluoroscopies, and operative complications, were recorded separately. The results of the clinical indicators, such as the visual analog scale (VAS) for back and leg pain and the Oswestry Disability Index (ODI) score, were obtained.

RESULTS

There were no significant differences in the patients' demographic data between the two groups. The single position group had a shorter operative time and fewer fluoroscopies than the bipedal position group; the single position group had a higher percentage of screw accuracy at the A level than the bipedal position group, but there was no statistically significant difference between the two groups at the acceptable level (A + B) (p > 0.05). The single-position group had better outcomes at the 1-week postoperative follow-up back pain VAS scores (p < 0.05). There was no statistically significant difference in the postoperative leg pain VAS scores or the ODI scores when compared to the control group.

CONCLUSION

Robot-assisted lateral position oblique lumbar interbody fusion with pedicle screw placement has the same accuracy as prone positioning. Single position surgery can significantly shorten the operation time and reduce the fluoroscopy. There was no significant difference in the long-term efficacy between the two groups.

Biomechanical evaluation of different oblique lumbar interbody fusion constructs: a finite element analysis

BACKGROUND

Finite element analysis (FEA) was performed to investigate the biomechanical differences between different adjunct fixation methods for oblique lumbar interbody fusion (OLIF) and to further analyze its effect on adjacent segmental degeneration.

METHODS

We built a single-segment (Si-segment) finite element model (FEM) for L4-5 and a double-segment (Do-segment) FEM for L3-5. Each complete FEM was supplemented and modified, and both developed two surgical models of OLIF with assisted internal fixation. They were OLIF with posterior bilateral percutaneous pedicle screw (TINA system) fixation (OLIF + BPS) and OLIF with lateral plate system (OLIF + LPS). The range of motion (ROM) and displacement of the vertebral body, cage stress, adjacent segment disc stress, and spinal ligament tension were recorded for the four models during flexion/extension, right/left bending, and right/left rotation by applying follower load.

RESULTS

For the BPS and LPS systems in the six postures of flexion, extension, right/left bending, and right/left rotation, the ROM of L4 in the Si-segment FEM were 0.32°/1.83°, 0.33°/1.34°, 0.23°/0.47°, 0.24°/0.45°, 0.33°/0.79°, and 0.34°/0.62°; the ROM of L4 in the Do-segment FEM were 0.39°/2.00°, 0.37°/1.38°, 0.23°/0.47°, 0.21°/0.44°, 0.33°/0.57°, and 0.31°/0.62°, and the ROM of L3 in the Do-segment FEM were 6.03°/7.31°, 2.52°/3.50°, 4.21°/4.38°, 4.21°/4.42°, 2.09°/2.32°, and 2.07°/2.43°. BPS system had less vertebral displacement, less cage maximum stress, and less spinal ligament tension in Si/Do-segment FEM relative to the LPS system. BPS system had a smaller upper adjacent vertebral ROM, greater intervertebral disc stress in terms of left and right bending as well as left and right rotation compared to the LPS system in the L3-4 of the Do-segment FEM. There was little biomechanical difference between the same fixation system in the Si/Do-segment FEM.

CONCLUSIONS

Our finite element analysis showed that compared to OLIF + LPS, OLIF + BPS (TINA) is more effective in reducing interbody stress and spinal ligament tension, and it better maintains the stability of the target segment and provides a better fusion environment to resist cage subsidence. However, OLIF + BPS (TINA) may be more likely to cause adjacent segment degeneration than OLIF + LPS.

Accuracy of the Cage Placement in Oblique Lumbar Interbody Fusion and its Effects on the Radiological Outcome in Lumbar Degenerative Disease

STUDY DESIGN

A retrospective study.

OBJECTIVES

This study aimed to check how accurately cages were inserted and how they affected the radiological results in oblique lumbar interbody fusion (OLIF) at L2-L5.

METHODS

A total of 137 patients diagnosed with lumbar degenerative disease, 184 intervertebral discs were included. We used a new cage deviation classification system on magnetic resonance imaging (MRI) to determine cage insertion accuracy. Cage deviation angles (CDA) were classified into four groups based on the angle formed by the long axis of the cage and the horizontal axis of the vertebral body. Other radiological parameters on plain radiographs and MRI were compared based on this classification.

RESULTS

Among 183 cages, 19 were in zone Ⅰ-Ⅱ (10.32%), 163 were in zone II-III (88.59%), and two were in zone III-IV (1.09%). The median cage deviation was 4.97°. No significant differences (H = 2.479, P = .290 > .05) of CDA were found among different segments. Posterior cage deviation accounted 94.57%. The minimal, mild, moderate, and severe cage deviation was 89 (48.4%), 51 (27.7%), 30 (16.3%), and 14 (7.6%) respectively. No differences in radiological parameter changes were noted among different cage obliquity categories.

CONCLUSIONS

Approximately 98.91% of cages were placed in zones I-II and II-III. Most cages deviated posteriorly with CDA ranging minimal to moderate. Minimal to moderate cage deviation did not impact radiological outcomes significantly in OLIF at L2-L5. However, avoiding severe cage deviation is crucial to prevent contralateral traversing nerve root injuries.

Using Novel Segmentation Technology to Define Safe Corridors for Minimally Invasive Posterior Lumbar Interbody Fusion

BACKGROUND AND OBJECTIVES

There has been a rise in minimally invasive methods to access the intervertebral disk space posteriorly given their decreased tissue destruction, lower blood loss, and earlier return to work. Two such options include the percutaneous lumbar interbody fusion through the Kambin triangle and the endoscopic transfacet approach. However, without accurate preoperative visualization, these approaches carry risks of damaging surrounding structures, especially the nerve roots. Using novel segmentation technology, our goal was to analyze the anatomic borders and relative sizes of the safe triangle, trans-Kambin, and the transfacet corridors to assist surgeons in planning a safe approach and determining cannula diameters.

METHODS

The areas of the safe triangle, Kambin, and transfacet corridors were measured using commercially available software (BrainLab, Munich, Germany). For each approach, the exiting nerve root, traversing nerve roots, theca, disk, and vertebrae were manually segmented on 3-dimensional T2-SPACE magnetic resonance imaging using a region-growing algorithm. The triangles' borders were delineated ensuring no overlap between the area and the nerves.

RESULTS

A total of 11 patients (65.4 ± 12.5 years, 33.3% female) were retrospectively reviewed. The Kambin, safe, and transfacet corridors were measured bilaterally at the operative level. The mean area (124.1 ± 19.7 mm2 vs 83.0 ± 11.7 mm2 vs 49.5 ± 11.4 mm2) and maximum permissible cannula diameter (9.9 ± 0.7 mm vs 6.8 ± 0.5 mm vs 6.05 ± 0.7 mm) for the transfacet triangles were significantly larger than Kambin and the traditional safe triangles, respectively (P < .001).

CONCLUSION

We identified, in 3-dimensional, the borders for the transfacet corridor: the traversing nerve root extending inferiorly until the caudal pedicle, the theca medially, and the exiting nerve root superiorly. These results illustrate the utility of preoperatively segmenting anatomic landmarks, specifically the nerve roots, to help guide decision-making when selecting the optimal operative approach.

Biomechanical differences between two different shapes of oblique lumbar interbody fusion cages on whether to add posterior internal fixation system: a finite element analysis

BACKGROUND

Oblique lateral lumbar fusion (OLIF) is widely used in spinal degeneration, deformity and other diseases. The purpose of this study was to investigate the biomechanical differences between two different shapes of OLIF cages on whether to add posterior internal fixation system, using finite element analysis.

METHODS

A complete three-dimensional finite element model is established and verified for L3-L5. Surgical simulation was performed on the verified model, and the L4-L5 was the surgical segment. A total of the stand-alone group (Model A1, Model B1) and the BPSF group (Model A2, Model B2) were constructed. The four OLIF surgical models were: A1. Stand-alone OLIF with a kidney-shaped Cage; B1. Stand-alone OLIF with a straight cage; A2. OLIF with a kidney-shaped cage + BPSF; B2. Stand-alone OLIF with a straight cage + BPSF, respectively. The differences in the range of motion of the surgical segment (ROM), equivalent stress peak of the cage (ESPC), the maximum equivalent stress of the endplate (MESE) and the maximum stress of the internal fixation (MSIF) were compared between different models.

RESULTS

All OLIF surgical models showed that ROM declines between 74.87 and 96.77% at L4-L5 operative levels. The decreasing order of ROM was Model A2 > Model B2 > Model A1 > Model A2. In addition, the ESPC and MESE of Model A2 are smaller than those of other OLIF models. Except for the left-bending position, the MSIF of Model B2 increased by 1.51-16.69% compared with Model A2 in each position. The maximum value of MESE was 124.4 Mpa for Model B1 in the backward extension position, and the minimum value was 7.91 Mpa for Model A2 in the right rotation. Stand-alone group showed significantly higher ROMs and ESPCs than the BPSF group, with maximum values of 66.66% and 70.59%. For MESE, the BPSF group model can be reduced by 89.88% compared to the stand-alone group model.

CONCLUSIONS

Compared with the traditional straight OLIF cage, the kidney-shaped OLIF cage can further improve the stability of the surgical segment, reduce ESPC, MESE and MSIF, and help to reduce the risk of cage subsidence.

Reverse Lumbar Pedicle Screw in Oblique Lateral Interbody Fusion: A Novel Concept to Restrict Cage Subsidence

OBJECTIVE

Cage subsidence is a common morbidity after oblique lumbar interbody fusion (OLIF), with risk of compromising clinical and radiographic outcomes. The study aims to describe an innovative reverse lumbar pedicle screw (RLPS) technique in OLIF and compare its effect on restricting cage subsidence with classical lateral fixation (LF) in radiological and clinical evaluation.

METHOD

Consecutive patients having undergone single-level OLIF-LF/RLPS from 2018 to 2020 were retrospectively reviewed. In OLIF-RLPS, the upper entry point was determined at the intersection between one horizontal line (1 cm above inferior endplate) and one vertical line (dissecting anterior and middle thirds of the vertebra) while the inferior entry point between one horizontal line (5 mm below superior endplate) and the same vertical line. Trajectories were from vertebrae reverse into contralateral pedicle. Radiological evaluation included disc height (DH) and segmental lordosis (SL); cage subsidence was evaluated by DH loss. Clinical assessment included visual analogue scale (VAS) and Oswestry disability index (ODI). Student t or Mann-Whitney U test was used for continuous variation according to normality analysis while Chi-square test for category variation.

RESULTS

A total of 29 patients had been enrolled in the study including 14 cases in the RLPS group and 15 cases in the LF group. The DH in the OLIF-RLPS group had increased from the preoperative 9.07 ± 1.73 mm to 13.73 ± 1.83 mm postoperatively, without significant difference compared with the OLIF-LF group during the perioperative, but decreased to 12.53 ± 1.74 mm in 3 months and maintained at 12.00 ± 1.45 mm in 12 months, significantly higher than the OLIF-LF group (p < 0.05). At the last follow-up, 7.1% (1/14) cases in the OLIF-RLPS group had shown subsidence of grade I, significantly less than 46.7% (7/15) cases in the OLIF-LF group. Pain and disability had improved similarly in two groups, without significant difference detected between two groups at the last follow-up.

CONCLUSION

RLPS technique with modified entry points and prolonged trajectory could effectively restrict cage subsidence in OLIF postoperatively compared with traditional lateral fixation.

Simultaneous Single-Position Oblique Lateral Interbody Fusion Combined With Unilateral Percutaneous Pedicle Screw Fixation for Single-Level Lumbar Tuberculosis: A 3-Year Retrospective Comparative Study

OBJECTIVE

To illustrate a simultaneous single-position oblique lateral interbody fusion (SPOLIF) combined with unilateral percutaneous pedicle screw fixation in treating single-level lumbar tuberculosis, compared with posterior-only approach in clinical and radiographic evaluations.

METHODS

Consecutive patients who had undergone surgeries for single-level lumbar tuberculosis from January 2018 to December 2020 were retrospectively reviewed. The patients included were divided into SP-OLIF and posterior-only groups according to surgical methods applied, with follow-up for at least 36 months. Outcomes included estimated blood loss, operative time, and complications for safety evaluation; visual analogue scale (VAS), Oswestry Disability Index (ODI) for efficacy evaluation; erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) for evaluating tuberculosis activity; x-ray and computed tomography scan were used for radiographic evaluation.

RESULTS

A total of 136 patients had been enrolled in the study (60 for SP-OLIF and 76 for Posterior-only). The median operative time, blood loss, and hospital stay in SP-OLIF group were significantly less, with a lower complication rate. Meanwhile, the SP-OLIF group showed substantially lower VAS in 1 and 7 days and decreased ODI in the first month postoperatively, without significant difference afterward. Similarly, the median CRP and ESR in SP-OLIF group were significantly lower in 3 and 7 days postoperatively. All indicators had reduced to normal after 3 months. No recurrence had been reported throughout the whole follow-up.

CONCLUSION

SP-OLIF was an efficient minimally invasive protocol for single-level lumbar tuberculosis, facilitating earlier clinical improvement, with decreased blood loss, operative time and hospital stay compared with posterior-only approach.

Should a Narrow Corridor Be a Contraindication for Performing Oblique Lateral Interbody Fusion Procedure or Not?

STUDY DESIGN

Retrospective study.

OBJECTIVES

We investigated the effect of corridor width on the postoperative outcomes of patients who underwent the OLIF procedure.

METHODS

Patients who underwent OLIF surgery, which included L4-5, between 2015 and 2021 were retrospectively studied. The patients were divided into three groups by the width of the corridor: not more than 10 mm, between 10 and 20 mm, and 20 mm or more. We compared clinical and radiographic outcomes and complications between these groups.

RESULTS

A total of 81 patients were included. There were no significant differences in VAS leg and back pain scores, ODI scores, or complications between each group. The radiographic findings, including cage position, anterior and posterior disc height, segmental Cobb angle, and foraminal height, also showed no significant differences between each group. The only radiographic finding that showed a significant difference between each group was the angle of the cage. We found significantly less degree of angle in the wider than 20 mm group when compared to the other two groups. (P-value = .01). There was no recorded incidence of major vascular complications.

CONCLUSIONS

The width of oblique corridor does not affect clinical outcomes, complications, or radiographic findings, including position of the cage, anterior and posterior disc height, segmental angle, and foraminal height after OLIF procedure, including L4-5 level. Thus, the OLIF procedure can be performed safely even in patients with limited oblique corridors, especially at L4-5.

Clinical, Radiographic and Fusion Comparison of Oblique Lumbar Interbody Fusion (OLIF) stand-alone and OLIF with posterior pedicle screw fixation in patients with degenerative spondylolisthesis

PURPOSE

To compare the outcomes and characteristics of oblique lumbar interbody fusion stand-alone (OLIF-SA) and OLIF with posterior pedicle screw fixation (OLIF-PPS) in the treatment of Grade I or Grade II degenerative lumbar spondylolisthesis.

PATIENTS AND METHODS

Between January 2019 and May 2022, 139 patients with degenerative spondylolisthesis were treated with OLIF-SA (n = 85) or OLIF-PPS (n = 54). The clinical and radiographic records were reviewed.

RESULTS

The clinical and radiographic outcomes were similar in both groups. The operative time and intraoperative blood loss in the OLIF-SA group were lower than those in the OLIF-PPS group (P < 0.05). However, the OLIF-PPS group had significantly better disc height (DH) and postoperative forward spondylolisthesis distance (FSD) improvement at 6 months (P < 0.05). The OLIF-PPS group had a significantly lower cage subsidence value than the OLIF-SA group (P < 0.05). Improvement of the lumbar lordotic angle (LA) and fusion segmental lordotic angle (FSA) in the OLIF-PPS group was significantly better than that in the OLIF-SA group (P < 0.05). In terms of fusion types, the OLIF-SA group tended to undergo fusion from the edge of the vertebral body. Fusion in the OLIF-PPS group began more often in the bone graft area of the central cage of the vertebral body. The fusion speed of the OLIF-SA group was faster than that of the OLIF-PPS group.

CONCLUSION

OLIF-SA has the advantages of a short operative time, less intraoperative blood loss, and reduced financial burden, while PPS has incomparable advantages in the reduction of spondylolisthesis, restoration of lumbar physiological curvature, and long-term maintenance of intervertebral DH. In addition, the SA group had a unique vertebral edge fusion method and faster fusion speed.

Predictors of Vertebral Endplate Fractures after Oblique Lumbar Interbody Fusion

Background

Cage subsidence after oblique lumbar interbody fusion (OLIF) induces restenosis and adversely affects patient outcomes. Many studies have investigated the causes of subsidence, one of which is endplate fracture (EF). This study aimed to identify predictors of EF after OLIF.

Methods

This retrospective study reviewed consecutive patients who underwent OLIF at a single institute between August 2019 and February 2022. A total of 104 patients were enrolled. The patients' demographic data and surgical details were collected through chart reviews. Radiographic variables were measured. Related variables were also analyzed using binomial logistic regression, dividing each group into those with versus without EF.

Results

EF occurred at 30 of 164 levels (18.3%), and the binary logistic analysis revealed that sex (odds ratio [OR], 11.07), inferior endplate concave depth (OR, 1.95), disc wedge angle (OR, 1.22), lumbar lordosis (OR, 1.09), pelvic incidence (OR, 1.07), sagittal vertical axis (OR, 1.02), sacral slope (OR, 0.9), L3-4 level (OR, 0.005), and L4-5 level (OR, 0.004) were significantly related to EF.

Conclusions

OLIF in older Asian patients should be performed carefully after recognizing the high possibility of EF and confirming the factors that should be considered preoperatively.

Antepsoas Approaches to the Lumbar Spine

Lumbar interbody fusion (LIF) is a well-established approach in treating spinal deformity and degenerative conditions of the spine. Since its inception in the 20th century, LIF has continued to evolve, allowing for minimally invasive approaches, high fusion rates, and improving disability scores with favorable complication rates. The anterior to the psoas (ATP) approach utilizes a retroperitoneal pathway medial to the psoas muscle to access the L1-S1intervertebral disc spaces. In contrast to the transpsoas arppoach, its primary advantage is avoiding transgressing the psoas muscle and the contained lumbar plexus, which potentially decreases the risk of injury to the lumbar plexus. Avoiding transgression of the psoas may minimize the risk of transient or permanent neurological deficits secondary to lumbar plexus injury. Indications for ATP approaches may expand as it is shown to be a safe and effective method of achieving spinal arthrodesis.

Efficacy of OLIF combined with pedicle screw internal fixation for lumbar spinal stenosis on spinal canal changes before and after surgery

PURPOSE

The purpose of the study was to evaluate the efficacy of OLIF combined with pedicle screw internal fixation in the treatment of lumbar spinal stenosis by assessing the changes in spinal canal before and after surgery.

METHODS

In this retrospective study, we included sixteen patients who underwent a combination of single-segment OLIF and pedicle screw internal fixation for the treatment of lumbar spinal stenosis at the Affiliated Hospital of Jiangxi University of Chinese Medicine between February 2018 and August 2022. The patients' pre- and post-operative data were compared. Intraoperative bleeding, duration of surgery, visual analogue score (VAS), Oswestry Disability Index (ODI), disc height (DH), cross-sectional area of vertebral canal (CSAVC), cross-sectional area of dural sac (CSADS), cross-sectional area of intervertebral foramen (CSAIF), spinal canal volume (SCV), spinal canal volume expansion rate, lumbar lordosis, and sagittal vertical axis were observed and recorded. The efficacy of OLIF combined with pedicle screw internal fixation for lumbar spinal stenosis on spinal canal changes before and after surgery was summarized.

RESULTS

The results showed that OLIF combined with pedicle screw internal fixation effectively restored disc height and increased the cross-sectional area of the spinal canal. It also had an indirect decompression effect. The intraoperative bleeding and duration of surgery were within acceptable ranges. The VAS and ODI scores significantly improved after surgery, indicating a reduction in pain and improvement in functional disability. The CSAVC, CSADS, CSAIF, SCV, and spinal canal volume expansion rate were all increased postoperatively. Additionally, there was improvement in lumbar lordosis and sagittal vertical axis. We conducted a follow-up of all patients at 1 year after the surgery. The results revealed that the parameter values at 1 year post-surgery showed varying degrees of decrease or increase compared to the immediate postoperative values. However, these values remained statistically significant when compared to the preoperative parameter values (P < 0.05).

CONCLUSIONS

OLIF combined with pedicle screw internal fixation effectively restores disc height and increases the cross-sectional area of the vertebral canal in patients with LSS, reflecting the indirect decompression effect. Measuring parameters such as DH, CSAVC, CSADS, CSAIF, SCV, and SCV expansion rate before and after surgery provides valuable information for evaluating the efficacy and functional recovery of the lumbar spine in LSS patients treated with OLIF surgery.

[An MRI study of lateral vascular safety zones in oblique lumbar interbody fusion surgery]

Objective

To study the anatomical characteristics of blood vessels in the lateral segment of the vertebral body through the surgical approach of oblique lumbar interbody fusion (OLIF) using MRI imaging, and evaluate its potential vascular safety zone.

Methods

The lumbar MRI data of 107 patients with low back and leg pain who met the selection criteria between October 2019 and November 2022 were retrospectively analyzed. The vascular emanation angles, vascular travel angles, and the length of vessels in the lateral segments of the left vertebral body of L 1-L 5, as well as the distance between the segmental vessels in different Moro junctions of the vertebral body and their distances from the edges of the vertebrae in the same sequence (bottom marked as I, top as S) were measured. The gap between the large abdominal vessels and the lateral vessels of the vertebral body was set as the lateral vascular safe zones of the lumbar spine, and the extent of the safe zones (namely the area between the vessels) was measured. The anterior 1/3 of the lumbar intervertebral disc was taken as the simulated puncture center, and the area with a diameter of 22 mm around it as the simulated channel area. The proportion of vessels in the channel was further counted. In addition, the proportions of segmental vessels at L 5 without a clear travel and with an emanation angel less than 90° were calculated.

Results

Except for the differences in the vascular emanation angles between L 4 and L 5, the vascular travel angles between L 1, L 2 and L 4, L 5, and the length of vessels in the lateral segments of the vertebral body among L 1-L 4 were not significant ( P>0.05), the differences in the vascular emanation angles, vascular travel angles, and the length of vessels between the rest segments were all significant ( P<0.05). There was no significant difference in the distance between vessels of L 1, L 2 and L 2, L 3 at Moro Ⅰ-Ⅳ junctions ( P>0.05), in L 3, L 4 and L 4, L 5 at Ⅱ and Ⅲ junction ( P>0.05). There was no significant difference in the vascular distance of L 2, L 3 between Ⅱ, Ⅲ junction and Ⅲ, Ⅳ junction, and the vascular distance of L 3, L 4 between Ⅰ, Ⅱ junction and Ⅲ, Ⅳ junction ( P>0.05). The vascular distance of the other adjacent vertebral bodies was significant different between different Moro junctions ( P<0.05). Except that there was no significant difference in the distance between L 2I and L 3S at Ⅰ, Ⅱ junction, L 3I and L 4S at Ⅱ, Ⅲ junction, and L 2I and L 3S at Ⅲ, Ⅳ junction ( P>0.05), there was significant difference of the vascular distance between the bottom of one segment and the top of the next in the other segments ( P<0.05). Comparison between junctions: Except for the L 3S between Ⅰ, Ⅱ junction and Ⅱ, Ⅲ junction, and L 5S between Ⅰ, Ⅱ junction and Ⅱ, Ⅲ and Ⅲ, Ⅳ junctions had no significant difference ( P>0.05), there were significant differences in the distance between the other segmental vessels and the vertebral edge of the same sequence in different Moro junctions ( P<0.05). The overall proportion of vessels in the simulated channels was 40.19% (43/107), and the proportion of vessels in L 1 (41.12%, 44/107) and L 5 (18.69%, 20/107) was higher than that in the other segments. The proportion of vessels in the channel of Moro zone Ⅰ (46.73%, 50/107) and zone Ⅱ (32.71%, 35/107) was higher than that in the zone Ⅲ, while no segmental vessels in L 1 and L 2 were found in the channel of zone Ⅲ ( χ 2=74.950, P<0.001). Moreover, 26.17% (28/107) of the segmental vessels of lateral L 5 showed no movement, and 27.10% (29/107) vascular emanation angles of lateral L 5 were less than 90°.

Conclusion

L 1 and L 5 segmental vessels are most likely to be injured in Moro zones Ⅰ and Ⅱ, and the placement of OLIF channels in L 4, 5 at Ⅲ, Ⅳ junction should be avoided. It is usually safe to place fixation pins at the vertebral body edge on the cephalic side of the intervertebral space, but it is safer to place them on the caudal side in L 1, 2 (Ⅰ, Ⅱ junction), L 3, 4 (Ⅲ, Ⅳ junction), and L 4, 5 (Ⅱ, Ⅲ, Ⅳ junctions).

Psoas Major Swelling Grade Affects the Clinical Outcomes after OLIF: A Retrospective Study of 89 Patients

OBJECTS

Oblique lumbar interbody fusion (OLIF) has gained increasing popularity recently. However, complications resulting from intraoperative retraction of psoas major (PM) sometimes occur. The aim of this study is to evaluate the degree of PM swelling by developing a scoring system called the Psoas Major Swelling Grade (PMSG), and to investigate the correlation between the PMSG and clinical outcomes after OLIF.

METHODS

Patients who underwent L4-5 OLIF at our hospital from May 2019 to May 2021 were reviewed and all data were recorded. The extent of postoperative PM swelling was determined by calculating the percentage of change in the PM area before and after surgery on MRI and divided into three grades subsequently. Swelling within the range of 0% to 25% was defined as grade I, 25%-50% was grade II, and more than 50% was grade III. All patients were grouped into the new grade system and followed up for at least 1 year, during which the visual analog scale (VAS) and Oswestry disability index (ODI) scores were recorded. Categorical data were analyzed using chi-square and Fisher's exact tests, while continuous variables were assessed with one-way ANOVA and paired t-tests.

RESULTS

Eighty-nine consecutive patients were enrolled in this study, with a mean follow-up duration of 16.9 months. The proportion of female patients in the PMSG I, II, and III groups was 57.1%, 58.3%, and 84.1%, respectively (p = 0.024).  Furthermore, the total complication rate was 43.2% in the PMSG III group, significantly higher than 9.5% and 20.8% in the PMSG I and II groups (p = 0.012). The incidence of thigh paraesthesia was also considerably higher in the PMSG III group at 34.1% (p = 0.015), compared to 9.5% and 8.3% in the PMSG I and II groups. Among the patients, 12.4% exhibited a teardrop-shaped PM, with the majority (90.9%) belonging to the PMSG III group (p = 0.012). Additionally, the PMSG III group demonstrated a higher estimated blood loss (p = 0.007) and significantly worse clinical scores at the 1-week follow-up assessment (p < 0.001).

CONCLUSION

PM swelling adversely affects the OLIF prognosis. Female patients with teardrop-shaped PM are more likely to develop swelling after OLIF. A higher PMSG is associated with a higher complication rate of thigh pain or numbness and worse short-term clinical outcomes.

Comparing Efficacy of Lumbar Disc Space Preparation via an Anterior-to-Psoas Approach Between Intraoperative Conventional Fluoroscopy and Computed Tomographic-Based Navigation System: A Cadaveric Study

OBJECTIVE

To compare the efficacy of intervertebral disc space preparation via an anterior-to-psoas (ATP) approach using conventional fluoroscopy (Flu) and computer tomography (CT)-based navigation by evaluating the disc remaining area.

METHODS

We equally assigned 24 lumbar disc levels from 6 cadavers into Flu and CT-based navigation (Nav) groups. Two surgeons performed disc space preparation using the ATP approach in both groups. Digital images of each vertebral endplate were obtained, and the remaining disc tissue was calculated in total and in quadrants. Operative time, number of attempts at disc removal, endplate violation area, number of endplate violation segments, and access angle were recorded.

RESULTS

The overall percentage of remaining disc tissue was significantly less in the Nav group than in the Flu group (32.7% vs. 43.3% respectively, P < 0.001). A significant difference was found in the posterior-ipsilateral (4.2% vs. 7.1%, P = 0.005) and posterior-contralateral (6.1% vs. 10.9%, P = 0.002) quadrants, respectively. No significant between-group difference was found concerning operative time, number of attempts at disc removal, endplate violation area, number of endplate violation segments, or access angle.

CONCLUSIONS

Intraoperative CT-based navigation may improve vertebral endplate preparation quality for an ATP approach, especially in the posterior quadrants. This technique may offer an effective alternative disc space and endplate preparation methods and may help enhance the fusion rates.

Correcting intervertebral rotation and scoliosis simultaneously by oblique lumbar interbody fusion: a 3D analysis of EOS images

Purpose

With advancements in minimally invasive techniques, oblique lumbar interbody fusion (OLIF) has gained widespread acceptance and is now commonly performed for adult degenerative scoliosis (ADS). The objective of this research paper is to evaluate three-dimensional (3D) intervertebral motions in EOS models before and after surgery and subsequently assess the efficacy of the 3D correction achieved through staged OLIF.

Methods

In this retrospective study, 29 consecutive patients diagnosed with ADS were included, with a mean age of 63.6 years, who underwent staged OLIF surgery between 2018 and 2021. Spinopelvic parameters were assessed using EOS images, and 3D models were reconstructed to measure intervertebral motion angles (IMAs) in 70 surgical intervertebral segments, comprising wedge, lordosis, and axial rotation angles. Regression analysis was conducted to compare IMAs in different planes before and after the staged OLIF surgery.

Results

Significant three-dimensional correction was observed in 70 intervertebral segments following the first-stage OLIF. The wedge angles decreased from 5.2°± 4.2° to 2.7°± 2.4° (P < 0.001). The lordosis angles increased from 5.1°± 5.9° to 7.8°± 4.6° (P = 0.014), while the axial rotation angles decreased from 3.8°± 2.6° to 2.3°± 2.1° (P < 0.001). Linear regression analysis revealed a positive correlation between wedge angles and axial angles preoperatively (P < 0.001, r = 0.43), as well as between corrected wedge angles and corrected axial angles (P < 0.001, r = 0.42).

Conclusion

This study demonstrated that intervertebral motions had a correlation between coronal and axial planes in lumbar degenerative scoliosis. First-stage OLIF was efficient at correcting segmental scoliosis by inserting cages while correcting rotation deformity simultaneously, as well as improving the sagittal spinopelvic parameters.

Recent Efficacy of Oblique Lateral Interbody Fusion Combined With Wiltse Approach Pedicle Screw Fixation for Degenerative Single-Level Lumbar Spondylolisthesis

BACKGROUND

The study aimed to explore the recent efficacy of oblique lateral interbody fusion (OLIF) combined with Wiltse approach pedicle screw fixation in the treatment of single-level degenerative lumbar spondylolisthesis (DLS).

METHODS

This is a retrospective study. The study enrolled 54 patients with single-level DLS who were treated at the Affiliated Jiangnan Hospital of Zhejiang Chinese Medical University from May 2018 to June 2020. (OLIF group) 24 cases operated using OLIF combined with Wiltse approach pedicle screw fixation, and (PLIF group) 30 cases operated by PLIF. The primary outcome measures were visual analog scale (VAS) pain scores, Oswestry dysfunction index (ODI), and the lower lumbar spine anterior convexity angle.

RESULTS

There were significant differences in VAS (2.63 ± 0.58 vs. 3.57 ± 0.63, P < 0.001) and ODI (9.67 ± 0.92 vs. 10.63 ± 1.40, P < 0.05) between the OLIF group and PLIF group on postoperative 3 days. And there was a significant decrease in VAS (2.63 ± 0.58 vs. 1.08 ± 0.28, P < 0.05) and ODI (3.57 ± 0.63 vs. 1.10 ± 0.31, P < 0.05) in both groups on postoperative 3 days and at 6 months postoperative comparisons. OLIF group showed better intervertebral space height and the lower lumbar spine anterior convexity angle scores on postoperative 3 days and 6 months, the difference was statistically significant(all P < 0.05).

CONCLUSIONS

OLIF combined with the Wiltse approach pedicle screw fixation can achieve good short-term clinical results in the treatment of single-level DLS. This surgical approach is less invasive, promotes early functional recovery, shortens hospitalization time, and improves the quality of life.

Lumbar Sympathetic Trunk Injury: An Underestimated Complication of Oblique Lateral Interbody Fusion

OBJECTIVE

Lumbar sympathetic trunk (LST) injury is one of the major complications after oblique lumbar interbody fusion (OLIF). LST injury often manifests as unequal skin temperature in lower limbs after operation, and there may be a large number of missed diagnoses due to the lack of attention and different diagnostic methods. The study aimed to investigate the incidence and clinical characteristics of LST injury after OLIF.

METHODS

The data of patients with lumbar degenerative diseases who underwent OLIF in our hospital from April 2016 to October 2017 were retrospectively analyzed. Finally, a total of 54 patients were included. There were 10 males and 44 females, aged 58.4 ± 10.9 years. The skin temperature of lower limbs was measured before and a day after surgery. The patients were followed up at 1 week, 6 weeks, 6 months, and 2 years after the surgery. Likert five-point scale was used to evaluate the discomfort caused by LST injury. Injury severity score was introduced to grade injury degree according to the recovery time of postoperative symptoms. The chi-square test was used to analyze the association of incidence of lumbar sympathetic trunk (LST) injury with contributing factors, such as gender and number of surgical segments.

RESULTS

The unequal temperature was not found before surgery in all the patients. Postoperatively, 16 cases (29.6%) had difference of skin temperature more than 0.5 °C and were diagnosed with LST injury. Eight patients (14.8%) had self-perception of skin temperature differences, and 12 patients (22.2%) had other symptoms, such as muscle pain, numbness, and weakness, which were not statistically different between patients with and without lumbar sympathetic trunk injury (p > 0.05). In the 16 patients with LST injury, the difference of skin temperature between the two legs was 0.6 ± 0.1 °C on the first day, and the temperature difference lasted for 1.5-~12 months. According to Likert five-point scale, two cases (12.5%) were poor, and 14 cases (87.5%) were moderate immediately after surgery. Fifteen cases improved to some extent 6 weeks to 12 months after surgery.

CONCLUSION

Postoperative LST injury is mainly manifested by different temperature of lower limbs. The incidence was higher in patients with multi-segment OLIF than in those with single-segment OLIF, and the subjective experience of most patients with LST injury was moderate discomfort.

Comparison of Oblique Lumbar Interbody Fusion Combined with Posterior Decompression (OLIF-PD) and Posterior Lumbar Interbody Fusion (PLIF) in the Treatment of Adjacent Segmental Disease(ASD)

BACKGROUND

An unintended consequence following lumbar fusion is the development of adjacent segment disease (ASD). Oblique lumbar interbody fusion combined with posterior decompression (OLIF-PD) is another feasible option for ASD, and there is no literature report on this combined surgical strategy.

METHODS

A retrospective analysis was performed on 18 ASD patients requiring direct decompression in our hospital between September 2017 and January 2022. Among them, eight patients underwent OLIF-PD revision and ten underwent PLIF revision. There were no significant differences in the baseline data between the two groups. The clinical outcomes and complications were compared between the two groups.

RESULTS

The operation time, operative blood loss and postoperative hospital stay in the OLIF-PD group were significantly lower than those in the PLIF group. The VAS of low back pain in the OLIF-PD group was significantly better than that in the PLIF group during the postoperative follow-up. The ODI at the last follow-up in the OLIF-PD group and the PLIF group were significantly relieved compared with those before operation. The excellent and good rate of the modified MacNab standard at the last follow-up was 87.5% in the OLIF-PD group and 70% in the PLIF group. There was a statistically significant difference in the incidence of complications between the two groups.

CONCLUSION

For ASD requiring direct decompression after posterior lumbar fusion, compared with traditional PLIF revision surgery, OLIF-PD has a similar clinical effect, but has a reduced operation time, blood loss, hospital stay and complications. OLIF-PD may be an alternative revision strategy for ASD.

Acceptable Fusion Rate of Single-Level OLIF Using Pure Allograft Combined with Posterior Instrumentation through the Wiltse Approach: A 2-Year Follow-Up Study

OBJECTIVE

Autogenic bone grafts have shown successful fusion rates in the treatment of degenerative lumbar disorders, but taking too many autogenic bones may result in donor site ischemia or infection. This study aimed to evaluate the outcomes of single-level oblique lumbar interbody fusion (OLIF) using pure allograft combined with posterior pedicle screw instrumentation through the Wiltse approach.

METHODS

A retrospective case analysis was performed on a series of consecutive patients who received a single-level OLIF procedure combined with posterior pedicle screw instrumentation through the Wiltse approach between July 1, 2017, and December 31, 2019, in which pure allogenic bone graft was used and filled in the large window of the cage. The patients were followed up as scheduled at 1 day and 3, 6, 12, 24 months after operation. Clinical outcome was assessed by multiple questionnaires, including Oswestry disability index (ODI), Japanese Orthopaedic Association (JOA) score rating system, short form-36 health survey (SF-36), and visual analog scale (VAS) for low back pain. Radiographic outcome was evaluated by measuring the parameters such as disc height, lumbar lordosis, and segmental angle on the standard standing lateral radiographs, and the space angle of the fusion level on the dynamic views of the lateral radiographs. Subsidence of the cage and intervertebral fusion status were evaluated on both the radiographic and CT scan images.

RESULTS

A total of 34 patients were finally included in this study. At 2-year follow-up, the VAS for low back pain, ODI, JOA, and SF-36 scores all had significant improvement (p < 0.001). Substantial increase of anterior and posterior disc heights was observed (p < 0.001). Both lumbar lordosis and segmental angle became larger (p < 0.05). No visible change of the space angle of the fusion level was found on the dynamic views. The 1-year fusion rate of 73.5% on CT scans proceeded to 82.4% at 2-year follow-up. The fusion rate was as high as 91.2% according to Bridwell interbody fusion grading system on radiographic images. The clinical outcomes in patients with incomplete fusion were just as good as those with complete fusion. The six patients with cage subsidence had higher ODI (p < 0.001) and lower JOA (p < 0.001) and SF-36 PCS (p = 0.011) scores than those without cage subsidence.

CONCLUSION

The use of pure allograft in single-level OLIF resulted in an acceptable fusion rate and satisfactory clinical effect at 2-year follow-up. Supplementation of posterior pedicle screw through the minimally invasive Wiltse approach ensured the favorable outcomes both clinically and radiographically.

Different Moro Zones of Psoas Major Affect the Clinical Outcomes after Oblique Lumbar Interbody Fusion: A Retrospective Study of 94 Patients

Oblique lumbar interbody fusion (OLIF) has been driven to the maturity stage in recent years. However, postoperative symptoms such as thigh paresthesia resulting from intraoperative retraction of the psoas major (PM) have sometimes occurred. The aim of this study was to assess the different positions and morphology of PM muscles and their relationship with clinical outcomes after OLIF by introducing the Moro zones. Patients who underwent L4-5 OLIF at our institution between April 2019 and June 2021 were reviewed and all data were recorded. All patients were grouped by Moro zones into a Moro A cohort and a Moro I and II cohort based on the front edges of their left PM muscles. A total of 94 patients were recruited, including 57 in the Moro A group and 37 in the Moro I and II group. Postoperative thigh pain or numbness occurred in 12 (21.1%) and 2 (5.4%) patients in the Moro A group and the Moro I and II group, respectively. There was no difference in the psoas major transverse diameter (PMTD) between groups preoperatively, while longer PMTD was revealed postoperatively in the Moro A group. The operating window (OW) and psoas major sagittal diameter (PMSD) showed significant differences within and between groups. Thirteen patients had teardrop-shaped PM muscles, with 92.3% in the Moro A group showing significantly worse clinical scores at 1-week follow-up. The Moro zones of the PM affected the short-term outcomes after OLIF. Preoperative measurements and analysis of OW, PMSD and PM morphology should be performed as necessary to predict short-term outcomes.

Oblique lateral interbody fusion in heterogenous lumbar diseases: Anterolateral screw fixation vs. posterior percutaneous pedicle screw fixation - A single center experience

Background

Oblique lateral interbody fusion (OLIF) is a type of minimally invasive lateral lumbar interbody fusion technique used for treating lumbar degenerative diseases. This study aimed to analyze the clinical and radiographic efficacy of OLIF with anterolateral screw fixation alone and OLIF requiring fixation with conventional posterior percutaneous pedicle screws for lumbar diseases.

Methods

Medical records of consecutive patients admitted to Cheng-Hsin Hospital who received OLIF between January 2019 and December 2020 were retrospectively reviewed. Patients were divided into two groups by screw fixation: patients who received anterolateral screw fixation alone were defined as one-stage OLIF (n = 9) and patients who received fixation with conventional posterior percutaneous pedicle screw were defined as two-stage OLIF (n = 16). Patient clinical characteristics, medical history, intraoperative blood loss, length of hospital stay, peri-operative, and post-operative complications were evaluated in all patients.

Results

During the study period, a total of 25 patients were successfully treated with OLIF (n = 9 one-stage; n = 16 two-stage). Two-stage OLIF was associated with longer operation times, longer hospital stays, shorter bed-rest time, and a greater likelihood of having a blood transfusion compared with the one-stage OLIF group. A higher proportion of grade I subsidence was observed at 6 months and 1 year after surgery in the two-stage group compared with the one-stage group. Post-operative complications included ileus, dystonia, and dystonia were higher in the two-stage OLIF group. Improvements in radiographic parameters were demonstrated after OLIF, and the improvements were comparable between one-stage and two-stage OLIF.

Conclusions

One-stage OLIF is a feasible and efficacious treatment method for single- and multiple-level degenerative lumbar diseases. Additional clinical follow-up is necessary to confirm long-term outcomes.

Multisegment transforaminal lumbar interbody fusion (TLIF) combined with Ponte osteotomy in degenerative lumbar scoliosis (DLS) surgery: a minimum of five years' follow-up

PURPOSE

To evaluate the long-term clinical outcomes of degenerative lumbar scoliosis (DLS) with the administration of multisegment transforaminal lumbar interbody fusion (TLIF) combined with Ponte osteotomy long-level fixation fusion, as well as to identify the factors affecting health-related quality of life (HRQOL).

METHODS

This was a retrospective single-centre study involving comprehensive clinical data. The Oswestry Disability Index (ODI), visual analog scale (VAS) outcomes, and Scoliosis Research Society (SRS-22) questionnaire were recorded to assess HRQOL. A correlation analysis was performed to determine the association between HRQOL and radiographic parameters.

RESULTS

A total of 41 consecutive patients (15 males and 26 females) met the inclusion criteria with a follow-up of 8.62 ± 1.20 years. Factors associated with HRQOL were significantly improved post-operation. Global sagittal parameters, including the sagittal vertebral axis (SVA) and T1 pelvic angle (TPA), and local parameters, including apical vertebral translation (AVT) and apical vertebral rotation (AVR), were significantly improved at the last follow-up. Significantly strong correlations between each clinical and radiographic parameter were demonstrated. Moreover, a multiple linear regression analysis demonstrated that the differences in AVT and AVR were significantly correlated with the difference in lumbar lordosis (LL), which was significantly correlated with the differences in SVA and TPA.

CONCLUSION

The surgical treatment of DLS with multisegment TLIF accompanied by Ponte osteotomy and long-level fixations improved the quality of life of patients with a long-term effect. AVR correction is an important factor for LL restoration that significantly correlates with improvements in the sagittal balance parameters SVA and TPA, which are key factors for guaranteeing good HRQOL.

Comparison of Posterior Pedicle Screw Fixation and Lateral Fixation in the Extreme Lateral Interbody Fusion in Lumbar Degenerative Disease Patients with Osteopenia or Osteoporosis

OBJECTIVE

Nowadays, with the increasing proportion of osteoporosis in patients with lumbar degenerative diseases, doctors are facing the choice of intraoperative internal fixation methods. The purpose of this study was to compare and assess the clinical results of posterior bilateral pedicle screw fixation and lateral fixation in the extreme lateral interbody fusion (XLIF) in patients with osteopenia or osteoporosis.

METHODS

The retrospective review was performed on 67 degenerative lumbar diseases patients with osteopenia or osteoporosis who underwent XLIF in our hospital from January 2018 to July 2021. Patients in this study were classified into lateral screw (LS) group, lateral self-locking plate (LP) group, and bilateral pedicle screw (BPS) group. The functional evaluation factors containing Japanese Orthopaedic Association (JOA) score, visual analogue scale (VAS) of leg pain, and VAS of low back pain, radiological factors such as disc height (DH), lumbar lordotic (LL) angle, segmental lordotic (SL) angle, cage subsidence degree and interbody fusion degree were compared.

RESULTS

Primary outcomes: no differences were observed with regards to the incidence of complications among LS, LP and BS group (P < 0.05). The JOA and leg pain VAS were significantly improved after operation (P < 0.05) and all groups demonstrated similar improvements in the leg pain VAS and JOA score (P > 0.05). When comparing VAS of leg pain and JOA scores, no differences were identified among LS, LP and BPS groups (P > 0.05). There are four thigh sensory complaint, one hip flexor weakness and one thigh pain occurred and no death was observed. There were significantly better DH, LL angle, SL angle, cage subsidence degree and interbody fusion degree in the BPS group than in LS and LP groups 1 year after surgery (P < 0.05). The DH loss ratio, LL angle loss ratio, SL angle loss ratio in the BPS group was significantly lower than in the LP and LS groups (P < 0.05). The 12-month SL angle improvement rate in the BPS group was significantly higher than in the LP and LS groups (20.20 ± 14.69, 0.73 ± 4.68, 6.20 ± 12.31, P < 0.05).

SECONDARY OUTCOMES

the BPS patients had significantly worse intraoperative blood loss and operation time than LS and LP patients (P < 0.05).

CONCLUSION

In lumbar diseases patients with osteopenia or osteoporosis, the bilateral pedicle screw fixation has better orthopedic effect than lateral internal fixation, and can better maintain the stability of the spine in the long-term follow-up, which is a better choice in XLIF surgery.

Application of Oblique Lateral Interbody Fusion Combined with Bridge-Locking Cage in Adjacent Segment Disease After Lumbar Fusion

OBJECTIVE

Adjacent segment disease (ASD) is considered any abnormal process that develops in the mobile segment next to spinal fusion, accompanied by related symptoms. To evaluate the efficacy and complications of oblique lateral interbody fusion (OLIF) combined with bridge-locking fusion on ASD after lumbar fusion.

METHODS

A total of 35 ASD patients who required re-operation after lumbar fusion in our hospital from March 2014 to March 2020 were retrospectively analyzed, among which 13 cases (seven males and six females; 62.3 ± 11.3 years old) received the treatment of OLIF + bridge-locking cage internal fixation (OLIF group), and 22 cases (14 males and eight females; 52.3 ± 17.8 years old) received the treatment of transforaminal lumbar interbody fusion (TLIF) + pedicle screw fixation (TLIF group). The comparison of the operation time, intraoperative blood loss, postoperative drainage volume, and length of hospital stay between the two groups of patients was performed using the t-test. The comparison of Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) at different time points before and after the operation was performed using analysis of variance for repeated measurement data. The fusion rate and postoperative complications of the two groups of patients were also evaluated.

RESULTS

The operation time of patients in the OLIF group (55.4 ± 12.4 min) was significantly shorter than that of patients in the TLIF group (94.3 ± 22.9 min) (P < 0.05), the length of stay of patients in the OLIF group (7.4 ± 2.3 day) was significantly shorter than that of patients in the TLIF group (12.4 ± 3.2 day) (P < 0.05); the intraoperative blood loss (62.2 ± 30.1 mL) and postoperative drainage (47.3 ± 22.4 mL) of patients in the OLIF group were significantly less than those of patients in the TLIF group with intraoperative blood loss (363.4 ± 120.2 mL) and postoperative drainage (285.5 ± 57.8 mL) (all Ps < 0.05). Besides, the VAS and ODI scores of the two groups of patients were improved 3 months after the operation and at the last follow-up (all Ps < 0.05). Three patients in the OLIF group developed complications such as hip flexion weakness and fusion cage sink, with an incidence of 23.1%. Three patients in the TLIF group developed complications including wound infection and intraoperative nerve injury, with an incidence of 22.7%.

CONCLUSION

The combination of OLIF and bridge-locking cage may be a safe and effective therapy for ASD patients after lumbar fusion operation.

Characteristics and hotspots of the 50 most cited articles in the field of pre-psoas oblique lumbar interbody fusion

PURPOSE

In the past decade, the field of pre-psoas oblique lumbar interbody fusion (OLIF) has developed rapidly, and with it, the literature on OLIF has grown considerably. This study was designed to analyze the top 50 articles in terms of the number of citations through bibliometric research to demonstrate the research characteristics and hotspots of OLIF.

METHOD

Searching the Web of Science database yielded the 50 most cited publications in the OLIF field as of July 10, 2022. The publications were ranked according to the number of citations. The following sources were evaluated: the year of publications, the number of citations, authors, countries, institutions, journals, research topics, and keyword hotspots.

RESULTS

The most productive period was from 2017 to 2020, with 41 articles. The number of citations varied from 10 to 140, with an average of 35.52, and 1,776 citations were found. World Neurosurgery published the most articles (12), China produced the most articles (16), and the Catholic University of Korea produced the most studies (6). The corresponding author who produced the most articles was J.S. Kim (5), and the first author who produced the most publications was S. Orita (3). The main research topics were anatomical morphology, surgical techniques, indications, outcomes, and complications. The top 10 most cited keywords were "complications," "decompression," "spine," "surgery," "outcomes," "transpsoas approach," "spondylolisthesis," "anterior," "disease," and "injury."

CONCLUSIONS

Certain articles can be distinguished from others using citation analysis as an accurate representation of their impact due to their long-term effectiveness and peer recognition. With these publications, researchers are provided with research priorities and hotspots through influential literature in the field of OLIF.

Oblique lateral interbody fusion stand-alone vs. combined with percutaneous pedicle screw fixation in the treatment of discogenic low back pain

Objective

Oblique lateral interbody fusion (OLIF) has unique advantages in the treatment of discogenic low back pain (DBP). However, there are few studies in this area, and no established standard for additional posterior internal fixation. The purpose of this study was to investigate the efficacy of OLIF stand-alone vs. combined with percutaneous pedicle screw fixation (PPSF) in the treatment of DBP.

Methods

This retrospective case-control study included forty patients. All patients were diagnosed with DBP by discography and discoblock. Perioperative parameters (surgery duration, blood loss, and muscle damage), complications, Visual analog scale (VAS), and Oswestry Disability Index (ODI) were assessed. Imaging data including cage subsidence, cage retropulsion, fusion rate, and adjacent spondylosis degeneration (ASD) were analyzed.

Results

There were 23 patients in the OLIF stand-alone group and 17 patients in the OLIF + PPSF group. The mean surgery duration, blood loss, and muscle damage in the OLIF stand-alone group were significantly better than those in the OLIF + PPSF group (P < 0.05). However, there was no significant difference in the average hospitalization time between the two groups (P > 0.05). There was no significant difference in the VAS and ODI scores between the two groups before surgery (P > 0.05), and VAS and ODI scores significantly improved after surgery (P < 0.05). The VAS and ODI scores in the OLIF stand-alone group were significantly better than those in the OLIF + PPSF group at 1 month (P < 0.05), While there was no significant difference between the two groups at 12 months and last follow up (P > 0.05). At the last follow-up, there was no significant difference in cage subsidence, fusion rate, ASD and complication rate between the two groups (P > 0.05).

Conclusion

OLIF stand-alone and OLIF + PPSF are both safe and effective in the treatment of DBP, and there is no significant difference in the long-term clinical and radiological outcomes. OLIF stand-alone has the advantages of surgery duration, blood loss, muscle damage, and early clinical effect. More clinical data are needed to confirm the effect of OLIF stand-alone on cage subsidence and ASD. This study provides a basis for the clinical application of standard DBP treatment with OLIF.

Comparison of short-term efficacy of MIS-TLIF and Endo-LIF in the treatment of single-segment degenerative lumbar diseases

Background

A prospective controlled study was conducted to compare the short-term clinical results and postoperative complications of minimally invasive transforaminal lumbar decompression and fusion (minimally invasive surgery transforaminal lumbar interbody fusion, MIS-TLIF) and percutaneous endoscope-assisted transforaminal lumbar interbody fusion (endoscopic lumbar interbody fusion, Endo-LIF) in the treatment of single-segment degenerative lumbar diseases, to provide some scientific guidance for clinicians to select surgical treatment for patients with lumbar degeneration.

Methods

From October 2020 to October 2021, a total of 62 patients were enrolled, with 31 patients in the MIS-TLIF group and 31 patients in the Endo-LIF group. All patients were followed up for 6 months. The following information from the two groups of patients was recorded: (1) operation time, radiation exposure time, intraoperative blood loss, bed rest time, and hospital stay; (2) ODI score (The Oswestry Disability Index), low back pain VAS score (Visual Analogue Scale), and lumbar vertebra JOA score (Japanese Orthopaedic Association Scores) 1 day before the operation; 1, 3, 6 days after operation; and 1, 3 and 6 months after operation. (3) X-ray evaluations of lumbar fusion at the last follow-up.

Results

There were significant differences in operation time, intraoperative fluoroscopy time, and hospitalization cost between the two groups. The MIS-TLIF group was significantly better than the Endo-LIF group, and the intraoperative bleeding volume of the Endo-LIF group was significantly better than that of the MIS-TLIF group, but there was no significant difference in postoperative bed rest time and postoperative hospital stay. There was no significant difference in the scores of ODI, VAS, and JOA between the two groups before and after the operation. At the last follow-up, the fusion rate was 100% in the MIS-TLIF group and 100% in the Endo-LIF group.

Conclusions

There was no significant difference in short-term clinical efficacy and safety between Endo-LIF and MIS-TLIF in the treatment of single-segment degenerative lumbar diseases, but MIS-TLIF was significantly better than Endo-LIF in terms of the operation time, hospitalization cost, and fluoroscopy time, and Endo-LIF was significantly better than MIS-TLIF in terms of intraoperative blood loss.

Meta-analysis of the clinical efficacy and safety of oblique lateral interbody fusion and transforaminal interbody fusion in the treatment of degenerative lumbar spondylolisthesis

Objective

The aim of this study was to comprehensively evaluate the efficacy of oblique lateral interbody fusion (OLIF) and transforaminal lumbar interbody fusion (TLIF) in the treatment of degenerative lumbar spondylolisthesis by meta-analysis.

Methods

A computer-based search of PubMed, Cochrane Library, Embase, Web of Science Core Collection databases, the China National Knowledge Infrastructure, China Biology Medicine, and Wanfang Digital Periodicals was conducted from the time of inception of each database to December 2021. The review process was conducted according to the PRISMA guidelines and registered in the PROSPERO database. Meta-analysis was performed using RevMan 5.4 software provided by the Cochrane Library.

Results

Thirteen studies were included in the statistical analysis. One randomized controlled study and 12 cohort studies with 954 patients were included. In terms of operation time, intraoperative blood loss, Oswestry disability index score, intervertebral height, and complications, the OLIF group was better than the TLIF group, and the difference was statistically significant (P < 0.05). There was no significant difference between the two groups in terms of visual analogue scale score, lumbar lordosis or fused segment lordosis (P > 0.05).

Conclusion

Both OLIF and TLIF are effective surgical modalities in the treatment of degenerative lumbar spondylolisthesis. They achieve similar therapeutic effects, but OLIF is superior to TLIF in restoring intervertebral height. At the same time, OLIF has the advantages of short operation time and less intraoperative blood loss.

Research of a Safe and Simplified Intertransverse Process Approach for the Lower Thoracic Interbody Surgery

Objective

To assess a safe surgical approach for intertransverse process lower thoracic intervertebral body fusion (ITIF) based on measurements from enhanced three‐dimensional CT reconstruction, cadaver simulated operation, and patient operation.

Methods

Enhanced three‐dimensional CT image reconstruction was performed for 20 healthy volunteers on thoracic segments T8–T12. The length of the transverse process (LTP), distance between the upper and lower transverse processes (DULTP), remote distance of the transverse process (RDTP), height of the extraforaminal intervertebral space (HEIS), and oblique diameter of the intervertebral space (ODIS) were measured and recorded. The blood vessels of the intertransverse lower thoracic region were observed, and their internal diameters were measured. The rib‐intervertebral space relationship for T10/11 and T11/12 was measured in 104 patients of the thoracic skeleton. Then, based on the data from the CT measurements, simulated surgery was performed on six human cadavers at the T11/12 level. An ankylosing spondylitis (AS) patient with a fracture of the T10/11 level was eventually operated on with the ITIF technique.

Results

No significant difference was found between the lengths of the left and right thoracic transverse processes. The relationship of the values of the LTP and RDTP for the measured vertebrae were found to be as follows:T8 > T9 > T10 > T11 > T12. For HEIS and DULTP, T8–9 < T9–10 < T10–11 < T11–12. The results for the ODIS were as follows: T8–T9 < T9–T10 < T10–T11 < T11–T12. The blood vessel inner diameter of T11–12 was less than that of T10–11, while there was no significant difference between the diameters for T8–9 and T11–12. Almost half of the volunteer's T10/11 intervertebral spaces were covered posteriorly by the 11th rib (45.19% on left and 41.35% on right), while for most patients, the T11/12 intervertebral space was not covered by the 12th rib (98.08%). According to the cadaver experiments, intervertebral bone grafting and ipsilateral pedicle screw fixation were performed to simulate the operation. One patient with a combined AS and T10/11 fracture was then operated on with the ITIF technique and followed up for 3 years with satisfactory results.

Conclusion

As verified by 3D CT reconstruction measurements, cadaver simulation surgery and patient operation with follow‐up, the intertransverse process approach for some T10/T11 and almost all T11/T12 segments is a safe surgical pathway for operations such as ITIF, fracture bone grafting, clearance of focal lesions.

Application of Offset Dingo Instruments in Anterior to Psoas (ATP)/Oblique Lumbar Interbody Fusion (OLIF) Procedure: A Retrospective Study of 80 Patients

OBJECTIVE

Oblique lumbar interbody fusion (OLIF) is a minimally invasive lumbar fusion procedure that has flourished in recent years. However, complications related to the anterior-to-psoas (ATP) approach have been reported. The purpose of this study was to assess the OLIF technique using offset design "Dingo" instruments for the treatment of degenerative lumbar disorders.

METHODS

A retrospective review was performed to identify patients between March 2018 and November 2020 who underwent OLIF with conventional or modified instruments with a minimum follow-up of 12 months. Demographic data were recorded. Operation time, intraoperative blood loss, and length of hospital stay were compared between cohorts. Imaging parameters were measured and compared between cohorts before and after surgery. Clinical outcomes were assessed at each follow-up visit. All complications were reviewed.

RESULTS

A total of 80 consecutive patients were included. The mean follow-up times for the conventional group and modified group were 14.5 months and 16.3 months, respectively. The incidence of hip flexion weakness was 27.5% and 7.5% for the conventional cohort and modified cohort, respectively. The modified group was associated with a shorter operation time, shorter length of hospital stay, higher postoperative disk height and better cage position. The symptoms of all patients improved after surgery. At 1-week follow-up, the modified group showed significantly better clinical scores.

CONCLUSIONS

OLIF with modified instruments and techniques shows promising outcomes in reducing approach-related complications. Additionally, the modified technique is associated with a better cage position, shorter length of hospital stay and less postoperative pain in the early period.

Oblique Lateral Interbody Fusion vs. Minimally Invasive Transforaminal Lumbar Interbody Fusion for Lumbar Spinal Stenosis: A Retrospective Cohort Study

Background

Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is an effective surgical option for lumbar spinal stenosis (LSS) with spondylolisthesis. However, few studies have discussed oblique lateral interbody fusion (OLIF) with MIS-TLIF.

Objective

To evaluate postoperative improvements, complications, and reoperation rates between patients with LSS undergoing OLIF or MIS-TLIF.

Methods

We retrospectively studied 113 LLS patients who underwent OLIF (53) or MIS-TLIF (60) with percutaneous pedicle screw fixation between January 2016 and December 2018. We measured estimated blood loss, operative time, hospital stay, reoperation, and complication incidence, visual analog scale (VAS), Oswestry Disability Index (ODI), Japanese Orthopedic Association (JOA), and Short Form-36 (SF-36) scores, discal and foraminal height and lumbar lordotic angle.

Results

The mean age was 58.81 ± 0.9 years. The TLIF group had increased operation time, blood loss, and hospital stays (p = 0.007, 0.001, and 0.016, respectively). Postoperatively, VAS and ODI scores significantly decreased while JOA and SF-36 scores significantly increased. The postoperative differences in main outcomes between the groups were insignificant (all p &gt; 0.05). The OLIF group had the lowest rates of overall (9.8% OLIF vs. 12.9% MIS-TLIF), intraoperative (3.9% OLIF vs. 4.8% MIS-TLIF), and postoperative complications (5.9% OLIF vs. 8.1% MIS-TLIF), but the differences were insignificant (p = 0.607, 0.813, and 0.653, respectively). The reoperation rate did not differ significantly (3.8% OLIF vs. 3.3% MIS-TLIF) (p = 0.842). OLIF restored disc height (74.4 vs. 32.0%), foraminal height (27.4 vs. 18.2%), and lumbar lordotic angle (3.5 vs. 1.1%) with greater success than did MIS-TLIF.

Conclusion

Patients undergoing OLIF with LSS improved similarly to MIS-TLIF patients. OLIF restored disc height, foraminal height and lumbar lordotic angle more successfully than did MIS-TLIF.

Comparative analysis of the effects of OLIF and TLIF on adjacent segments after treatment of L4 degenerative lumbar spondylolisthesis

Background

The fusion of the lumbar spine may lead to the degeneration of the adjacent segments. In this study, the effects of OLIF and TLIF on adjacent segments after treatment of L4 degenerative lumbar spondylolisthesis (DLS) were compared and analysed.

Methods

This was a retrospective analysis of the medical records of consecutive patients treated with OLIF or TLIF for L4DLS. They were divided into the OLIF group and TLIF group based on different treatment methods. Cage height, segmental lordosis (SL), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS) were compared between the two groups, and the postoperative biomechanical changes were analysed by establishing the disc angle (DA). The clinical outcomes were analysed by comparing the visual analogue scale (VAS), Oswestry Disability Index (ODI) and incidence of adjacent segment disease (ASDis) between the two groups. The intervertebral disc height (IDH), intervertebral foramen height (IDH), intervertebral foramen area (IFA), sliding distance (SD), and angular displacement (AD) in L3-4 and L5-S1 were compared between the two groups. The incidence of aggravated disc degeneration (ADD), the incidence of aggravated zygapophyseal joint degeneration (AJD) and the incidence of adjacent segment degeneration (ASDeg) were compared between the two groups for radiological degeneration.

Results

At the last follow-up, there was one case of ASDis in the OLIF group (2.78%) and two cases in the TLIF group (5.56%). At the last follow-up, compared with the preoperative values, IDH, IFH, and IFA of the adjacent segments above and below L4-5 decreased in both groups (P < 0.05); the SD and AD increased in both groups (P < 0.05). The cage height and L4-5 IDH in the OLIF group were significantly higher than those in the TLIF group (P < 0.05). SL, LL, PT, SS, and L5- S1DA were significantly improved in the OLIF group compared with the TLIF group (P < 0.05). The incidence of L3-4ASDeg in the two groups was higher than that of L5-S1. The incidence of ASDeg and the incidence of L5-S1ADD in the OLIF group were lower than those in the TLIF group, but the incidence of L5-S1AJD was higher than that in the TLIF group.

Conclusion

L4DLS after OLIF and TLIF treatment will cause adjacent segment degeneration, and L3-4 degeneration is more obvious than L5-S1 degeneration. OLIF has more advantages in restoring lumbar sagittal balance. Compared with TLIF, OLIF can weaken the degeneration of the L5-S1 disc and increase the degeneration of the L5-S1 zygapophyseal joints.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03084-7.

Pearls and Pitfalls of Oblique Lateral Interbody Fusion: A Comprehensive Narrative Review

Lumbar degenerative disease is a common problem in an aging society. Oblique lateral interbody fusion (OLIF) is a minimally invasive surgical (MIS) technique that utilizes a retroperitoneal antepsoas corridor to treat lumbar degenerative disease. OLIF has theoretical advantages over other lumbar fusion techniques, such as a lower risk of lumbar plexus injury than direct lateral interbody fusion (DLIF). Previous studies have reported favorable clinical and radiological outcomes of OLIF in various lumbar degenerative diseases. The use of OLIF is increasing, and evidence on OLIF is growing in the literature. The indications for OLIF are also expanding with the help of recent technical developments, including stereotactic navigation systems and robotics. In this review, we present current evidence on OLIF for the treatment of lumbar degenerative disease, focusing on the expansion of surgical indications and recent advancements in the OLIF procedure.

Endoscopic Techniques for Lumbar Interbody Fusion: Principles and Context

Endoscopic techniques in spine surgery are rapidly evolving, with operations becoming progressively safer and less invasive. Lumbar interbody fusion (LIF) procedures comprise many spine procedures that have benefited from endoscopic assistance and minimally invasive approaches. Though considerable variation exists within endoscopic LIF, similar principles and techniques are common to all types. Nonetheless, innovations continually emerge, requiring trainees and experienced surgeons to maintain familiarity with the domain and its possibilities. We present two illustrative cases of endoscopic transforaminal lumbar interbody fusion with a comprehensive literature review of the different approaches to endoscopic LIF procedures.

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.

Efficacy and Safety of Oblique Lumbar Interbody Fusion Versus Transforaminal Lumbar Interbody Fusion for Degenerative Lumbar Spondylolisthesis: A Systematic Review and Meta-Analysis

OBJECTIVE

We critically evaluated the efficacy and safety of oblique lumbar interbody fusion (OLIF) versus transforaminal lumbar interbody fusion (TLIF) for degenerative lumbar spondylolisthesis (DLS).

METHODS

PubMed, Embase, Cochrane Library, the Web of Science Core Collection, Chinese Biomedical Literature, China National Knowledge Infrastructure, Wanfang Digital Periodicals, and Chinese Science and Technology Periodicals were searched from their inception to February 2021. Randomized controlled trials and retrospective or prospective cohort studies (CSs) comparing OLIF and TLIF for DLS were included. A meta-analysis was conducted, if possible.

RESULTS

Ten studies were included in the statistical analysis. The pooled results of the CSs showed no statistically significant differences (P > 0.05) in pain relief at 3 or 6 months of follow-up and functional improvement at 1 or 3 months of follow-up in DLS patients between those who had undergone OLIF versus TLIF. The pooled results of the CSs showed that OLIF could significantly improve the degree of lumbar lordosis, foraminal height, and disc height and decrease the intraoperative blood loss, postoperative drainage volume, operative duration, bed rest time, and hospital length of stay (P < 0.05) compared with TLIF. The incidence of adverse events was not significantly different statistically between OLIF and TLIF.

CONCLUSIONS

The results from the present study suggest that pain relief and functional improvement were not significantly different between OLIF and TLIF. Nevertheless, the use of OLIF might improve radiological outcomes and reduce intraoperative blood loss, postoperative drainage volume, operative duration, bed rest duration, and hospital length of stay compared with TLIF. Additional high-quality randomized controlled trials are still required to confirm these findings.

Stability Evaluation of Different Oblique Lumbar Interbody Fusion Constructs in Normal and Osteoporotic Condition - A Finite Element Based Study

Introduction: In developed countries, the age structure of the population is currently undergoing an upward shift, resulting a decrease in general bone quality and surgical durability. Over the past decade, oblique lumbar interbody fusion (OLIF) has been globally accepted as a minimally invasive surgical technique. There are several stabilization options available for OLIF cage fixation such as self-anchored stand-alone (SSA), lateral plate-screw (LPS), and bilateral pedicle screw (BPS) systems. The constructs’ stability are crucial for the immediate and long-term success of the surgery. The aim of this study is to investigate the biomechanical effect of the aforementioned constructs, using finite element analysis with different bone qualities (osteoporotic and normal).

Method: A bi-segmental (L2–L4) finite element (FE) model was created, using a CT scan of a 24-year-old healthy male. After the FE model validation, CAD geometries of the implants were inserted into the L3–L4 motion segment during a virtual surgery. For the simulations, a 150 N follower load was applied on the models, then 10 Nm of torque was used in six general directions (flexion, extension, right/left bending, and right/left rotation), with different bone material properties.

Results: The smallest segmental (L3–L4) ROM (range of motion) was observed in the BPS system, except for right bending. Osteoporosis increased ROMs in all constructs, especially in the LPS system (right bending increase: 140.26%). Osteoporosis also increased the caudal displacement of the implanted cage in all models (healthy bone: 0.06 ± 0.03 mm, osteoporosis: 0.106 ± 0.07 mm), particularly with right bending, where the displacement doubled in SSA and LPS constructs. The displacement of the screws inside the L4 vertebra increased by 59% on average (59.33 ± 21.53%) due to osteoporosis (100% in LPS, rotation). BPS-L4 screw displacements were the least affected by osteoporosis.

Conclusions: The investigated constructs provide different levels of stability to the spine depending on the quality of the bone, which can affect the outcome of the surgery. In our model, the BPS system was found to be the most stable construct in osteoporosis. The presented model, after further development, has the potential to help the surgeon in planning a particular spinal surgery by adjusting the stabilization type to the patient’s bone quality.

Single-stage debridement via autogenous iliac bone graft through the OLIF corridor and lateral fixation in treating spontaneous single-level lumbar pyogenic spondylodiscitis

BACKGROUND

The aim of the present study was to investigate the efficacy and safety of mini-open oblique debridement and lumbar interbody fusion combined with lateral screw fixation for treating single-level pyogenic spondylodiscitis.

METHODS

Twelve patients with single-level lumbar pyogenic spondylodiscitis underwent OLIF combined with lateral screw fixation were analyzed. Patients underwent follow-up for 12 to 24 months. The clinical characteristics, etiological examinations, operative time, intraoperative blood loss, Oswestry Disability Index (ODI), visual analog scale score (VAS), postoperative complications, and the bony fusion rate were recorded.

RESULTS

The mean follow-up period of time was 14.8 months. The average operative time and intra-operative blood loss were 129.0 ± 19.76 min and 309.2 ± 92.96 mL, respectively. No severe intra-operative complications were observed during surgery, except in 1 case that develops abdominal pain and distension after surgery, 2 cases that develop left-sided transient thigh pain/numbness and 8 cases that complains of donor site (iliac crest) pain. All of these symptoms disappeared 8 weeks after surgery. Tissue sample cultures were obtained from all patients intraoperatively and four (33.3%) were positive, including 2 with Staphylococcus aureus, 1 with Staphylococcus epidermidis, and 1 with Escherichia coli. During an average of 22.5 ± 2.1 days (range, 14-29 days) after surgery, WBC, CPR, and ESR levels in all patients had returned to normal. All patients were pain free with no recurring infection. Solid bony fusions were observed in all cases within 6 months, including 10 with I grade fusion, 2 with II grade fusion according to the classification suggested by Burkus et al. No fixation failure was observed during follow up and solid bony fusions were observed in all 12 patients at finally follow-up. A significant postoperative increase was also observed in the mean segmental height and lordosis (P < 0.05), followed by a slight decrease of segmental height and lordosis at final follow-up. At the final follow up, the mean VAS (1.5 ± 0.6) and ODI (18.9 ± 7.6) were significantly lower than VAS (8.4 ± 2.7) and ODI (71.2 ± 16.5) before surgery (P < 0.01).

CONCLUSION

Single-stage debridement with autogenous iliac bone graft through the OLIF corridor and lateral fixation was a feasible surgical approach in our consecutive 12 cases of pyogenic spondylitis.