Review of early clinical results and complications associated with oblique lumbar interbody fusion (OLIF)

Single-position oblique lumbar interbody fusion with navigation: improved efficiency and screw accuracy compared to dual-position with fluoroscopy

Dual-position oblique lumbar interbody fusion with fluoroscopy (D-OLIF) requires repositioning the patient to a prone position for pedicle screw insertion. Recently, single-position surgery with navigation has been introduced. However, there are concerns regarding pedicle screw accuracy and achieving appropriate sagittal balance in single-position OLIF with navigation (S-OLIF). The purpose of this study is to evaluate the clinical and radiological outcomes of S-OLIF compared to D-OLIF. A retrospective analysis was conducted on 102 patients who underwent single-level OLIF at a single institution. The patients were divided into two groups: 55 in the S-OLIF group and 47 in the D-OLIF group. The numeric rating scale for back and leg, Oswestry disability index, and walking distance improvements showed no significant difference. However, the EuroQol 5-dimension 5-level index showed higher improvement in the S-OLIF (P = 0.029). The segmental lordosis, lumbar lordosis, and C7 sagittal vertical axis showed no significant difference. S-OLIF had significantly fewer cases of pedicle screw malposition (P = 0.045). Additionally, the surgery time was shorter in the S-OLIF (P = 0.002). In conclusion, S-OLIF exhibited clinical and radiological outcomes comparable to D-OLIF, with the added advantages of reduced surgery time and enhanced accuracy in pedicle screw placement.

Short-Term Comparison Between Unilateral Versus Bilateral Percutaneous Pedicle Screw Fixation in Short-Level Lateral Lumbar Interbody Fusion-A Prospective Randomized Study

STUDY DESIGN

Prospective randomized controlled trial.

OBJECTIVES

No prospective studies have directly compared clinical and radiographic outcomes of unilateral vs bilateral instrumented lateral lumbar interbody fusion (LLIF) for lumbar degenerative disease (LDD). We compared the short-term radiographic, clinical outcomes, and some complications of the unilateral percutaneous pedicle screw (PPS) (UPS) vs bilateral PPS (BPS) fixation in short-level spinal fusion with LLIF for LDD.

METHODS

This was a prospective randomized controlled study of 33 patients who underwent UPS or BPS fixation after LLIF for LDD; 18 patients were assigned to the UPS group and 15 patients to the BPS group. Clinical outcomes, complication rates, and fusion rates were assessed.

RESULTS

The two groups were similar in age, sex, preoperative diagnosis, and level of surgery. Blood loss, length of hospital stay, and numeric rating scale score one year after surgery did not differ between groups. The operative time was longer in the BPS than UPS group (120.2 vs 88.8 min, respectively; P = .029). Both groups showed improvement in disc height and dural sac in the immediate postoperative computed tomography and magnetic resonance imaging, which did not differ significantly between groups. The subsidence grade and fusion rate did not differ, but cage subsidence was more severe in the UPS than BPS group.

CONCLUSION

Unilateral and bilateral PPS fixation after LLIF yielded similar short-term clinical and radiological outcomes. However, severe cage subsidence was more common in the UPS group, which suggests that BPS fixation after LLIF may be a better choice over the long term.

Advances in Anterolateral Approaches to the Lumbar Spine: A Focus on Technological Developments

A historical overview of the evolution of anterolateral approaches to the lumber spine and associated patient outcomes is presented. In addition, the modern incorporation of new technologies is discussed, including interbody cages, intraoperative image guidance, robotics, augmented reality, and machine learning, which have significantly improved the spine surgery safety and efficacy profile. Current challenges and future directions are also covered, emphasizing the need for further research and development, particularly in robotic assistance and machine learning algorithms.

Anterior column realignment via a minimally invasive hybrid approach in adult spinal deformity surgery: a short-term retrospective study

BACKGROUND

Anterior column realignment (ACR) is a novel surgical method for correcting spinal sagittal balance. meanwhile, oblique lumbar interbody fusion (OLIF) and anterior lumbar interbody fusion (ALIF) are considered minimally invasive surgical methods through natural anatomical space. This study aimed to explore the corrective effects and clinical outcomes of OLIF or ALIF combined with ACR technology in patients with adult spinal deformity (ASD).

METHODS

We retrospectively analyzed patients with sagittal imbalance who received OLIF and/or ALIF and ACR treatment from 2018 to 2021. Surgical time and intraoperative bleeding volume are recorded, the corrective effect is determined by the intervertebral space angle (IVA), lumbar lordosis (LL), the sagittal vertical axis (SVA), clinical outcome is evaluated by preoperative and final follow-up visual analog pain score (VAS), Japanese orthopedic association scores (JOA) and complications.

RESULTS

Sixty-four patients were enrolled in the study, average age of 65.1(range, 47-82) years. All patients completed 173 fusion segments, for 150 segments of ACR surgery. The operation time of ALIF-ACR was 50.4 ± 22.1 min; The intraoperative bleeding volume was 50.2 ± 23.6 ml. The operation time and intraoperative bleeding volume of single-segment OLIF-ACR was 66.2 ± 19.4 min and 70.2 ± 31.6 ml. At the follow-up of 6 months after surgery, the intervertebral space angle correction for OLIF-ACR and ALIF-ACR is 9.2° and 12.2°, the preoperative and postoperative lumbar lordosis were 16.7° ± 6.4°and 47.1° ± 3.6° (p < 0.001), VAS and JOA scores were improved from 6.8 to 1.8 and 7.8 to 22.1 respectively, statistically significant differences were observed in these parameters. The incidence of surgical related complications is 29.69%, but without serious complications.

CONCLUSION

ACR via a minimally invasive hybrid approach for ASD has significant advantages in restoring local intervertebral space angulation and correcting the overall sagittal balance. Simultaneously, it can achieve good clinical outcomes and fewer surgical complications.

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.

Factors affecting successful immediate indirect decompression in oblique lateral interbody fusion in lumbar spinal stenosis patients

Background

Oblique lumbar interbody fusion (OLIF) offers indirect decompression of stenotic lesions of the spinal canal and foramen through immediate disc height restoration. Only a few studies have reported the effect of cage position and associated intraoperatively modifiable factors for successful immediate indirect decompression following OLIF surgery. This study aimed to investigate the intraoperatively modifiable factors for successful radiological outcomes of OLIF.

Methods

This study included 46 patients with 80 surgical levels who underwent OLIF without direct posterior decompression. Preoperative and postoperative radiological parameters were evaluated and intraoperatively modifiable radiologic parameters for successful immediate radiologic decompression on magnetic resonance image (MRI) were determined. Radiologic parameters were preoperative and postoperative radiological parameters including anterior disc height (ADH), posterior disc height (PDH) lumbar lordotic angle (LLA), segmental lordotic angle (SLA), foraminal height (FH), cage position, cross-sectional area (CSA) of the thecal sac, cross-sectional foraminal area (CSF), facet distance (FD).

Results

All radiologic outcomes significantly improved. Comparing preoperative and postoperative values, mean CSA increased from 99.63±40.21 mm2 to 125.02±45.90 mm2 (p<.0001), and mean left CSF increased from 44.54±12.90 mm2 to 69.91±10.80 mm2 (p<.0001). FD also increased from 1.40±0.44 to 1.92±0.71 mm (p<.0001). FH increased from 16.31±3.3 to 18.84±3.47 mm (p<.0001). ADH and PDH also significantly increased (p<.0001). Immediate postoperative CSF and FH improvement rate (%) were significantly correlated with posterior disc height restoration rate (%) (p=.0443, and p=.0234, respectively). In addition, the patients with a cage positioned in the middle of the vertebral body experienced a greater FH improvement rate (%) compared to the patients with a cage positioned anteriorly. Finally, Visual analogue scale (VAS) for leg pain was improved immediately.

Conclusions

OLIF provided satisfactory immediate indirect decompression in central and foraminal spinal stenosis. Moreover, intraoperative surgical technique for successful radiologic CSF and FH improvement included restoration of the PDH and placement of the cage in the middle.

Design and Biomechanical Evaluation of a Bidirectional Expandable Cage for Oblique Lateral Interbody Fusion

OBJECTIVE

Oblique lateral interbody fusion (OLIF) surgery is a minimally invasive spinal surgery technique that has become increasingly popular in recent years. The primary objective of the current study was to design a minimally invasive expandable fusion device that can reduce iatrogenic nerve damage and minimize endplate damage during OLIF surgery, while restoring intervertebral height and alignment. The second objective was to use finite element analysis to evaluate the biomechanical stability of the newly designed expandable fusion device after implantation into the intervertebral space.

METHODS

A new bidirectional expandable cage was designed in this study. A finite element model (FEM) of L3-L5 lumbar segment was modified to simulate decompression and fusion. The modified FEMs were constructed in the following cases: intact model, bidirectional expandable cage (alone, with unilateral pedicle screws [UPSs], and with bilateral pedicle screws [BPSs]) model, conventional OLIF cage (alone, with UPSs, and with BPSs) model. To simulate physiological loadings, the models were subjected to a follower compressive pre-load of 400 N, in addition to 8.0 Nm of flexion, extension, lateral bending, and axial rotation moments.

RESULT

All modified FEMs exhibited a significant reduction in motion at L3-L5 compared to the intact model. Among the fusion models, the bidirectional expandable cage (BEC) with BPS model displayed the highest stiffness and demonstrated a reduced range of motion (48.5%-75.7%). Additionally, the peak stress on the endplate in the conventional OLIF cage (Conv-OLIF) model was generally lower than that in the BEC models. The cage in the BEC ALONE model exhibited the highest stress (93.87-176.3 MPa) on the endplate in most motion modes, while the cage in the Conv-OLIF+BPS model had the lowest stress (16.67-30.58 MPa) on the endplate in most motion modes. The maximum stress on the fixation in the BEC fusion models was generally lower than that in the Conv-OLIF fusion group under the same loading conditions. The OLIF ALONE model had the lowest stress on the adjacent disc, while the stress level in the BEC ALONE model was very close to it.

CONCLUSIONS

The BEC implanted models had higher stiffness, and more proper stress distribution on the posterior fixation was comparable to that of the Conv-OLIF models. However, the endplate stress peaks and cage stress peaks of the BEC models were slightly higher than those of the Conv-OLIF models, though still within a clinically acceptable range. Taking into account both biomechanical and clinical perspectives, BEC-assisted unilateral pedicle screw fixation meet clinical demand and may serve as a viable alternative to Conv-OLIF fusion.

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.

Clinical and radiographic outcomes of oblique lumbar interbody fusion with anterolateral screw and rod instrumentation in osteopenia patients: a retrospective study

PURPOSE

The purpose of this paper is to evaluate the clinical and radiographic outcomes of oblique lumbar interbody fusion (OLIF) to perform in L4/5 degenerative lumbar spondylolisthesis (DLS) patients who diagnosed with osteopenia.

METHODS

From December 2018 to 2021 March, 94 patients were diagnosed with degenerative spondylolisthesis underwent OLIF and divided into two groups with different bone mineral density. Anterolateral screw and rod instrumentation was applied in two groups. The primary outcomes were VAS, JOA and ODI. The secondary outcomes included disc height (DH), cross-sectional height of the intervertebral foramina (CSH), cross-sectional area of the dural sac (CSA), lumbar lordorsis (LL), pelvic titlt (PT), pelvic incidence (PI) and sacrum slop (SS).

RESULTS

All patients finished at least 1 years follow-up with 21.05 ± 4.42 months in the group A and 21.09 ± 4.28 months in the group B. The clinical symptoms were evaluated by VAS, JOA and ODI and 94 patients showed good outcomes at final follow-up (P < 0.05), with significant increases in DH, CSH and CSA. In group A, DH increased from 8.54 ± 2.48 to 11.11 ± 2.63 mm, while increased from 8.60 ± 2.29 to 11.23 ± 1.88 were recorded in group B. No statistical difference was found in DH between the two groups (P > 0.05). The cage subsidence was 1.14 ± 0.83 mm in group A and 0.87 ± 1.05 mm in group B (P > 0.05). There was no significant difference in the adjusted parameters of spino-pelvic between two groups (P > 0.05).

CONCLUSION

Oblique lumbar interbody fusion with anterolateral screw and rod instrumentation is feasible to be performed in osteopenia patients who diagnosed with degenerative spondylolisthesis.

Circumferential Bone Fusion in Adult Spinal Deformity via Combination of Oblique Lateral Interbody Fusion and Grade 2 Posterior Column Osteotomy

STUDY DESIGN

Retrospective study.

OBJECTIVES

The combination of oblique lateral interbody fusion (OLIF) with grade 2 posterior column osteotomy (PCO) is an effective treatment for adult spinal deformity. However, grade 2 PCO may lead to pseudoarthrosis because it involves complete removal of the bilateral posterior facet joints. The main study objective was to determine the achievement rate of anterior and posterolateral fusion resulting in circumferential fusion in patients who underwent combined OLIF and grade 2 PCO.

METHODS

This retrospective study included consecutive patients who underwent OLIF and grade 2 PCO. The group comprised a long fusion group, with fusion from the thoracic level to the ilium, and a short fusion group, with fusion within the lumbar region. The OLIF with percutaneous pedicle screw insertion group was also used for reference. The Brantigan-Steffee-Fraser classification was used to assess interbody fusion and Lenke classification for assessment of posterolateral fusion.

RESULTS

Sixty-six patients with 109 lumbar levels were included in the study. We observed 100% anterior fusion in all 3 groups. The fusion rate for posterolateral fusion between the OLIF-grade 2 PCO group was 97%, with very low (3%) non-circumferential fusion (pseudoarthrosis only at the osteotomy site). In most cases, solid posterolateral fusions (Lenke A) occurred within 24 months.

CONCLUSIONS

The combination of OLIF and grade 2 PCO resulted in circumferential fusion for most (97%) of the cases within 24 months. OLIF and grade 2 PCO are considered a good combination treatment to achieve sufficient lumbar lordosis and solid bone fusion.

Elucidation of the Mechanism of Occasional Anterior Longitudinal Ligament Rupture with Posterior Correction Procedure for Adult Spinal Deformity Using LLIF-Finite Element Analysis of the Impact of the Lordotic Angle of Intervertebral LLIF Cage

Background and Objectives: There are several advantages of using lateral lumbar interbody fusion (LLIF) for correction surgeries for adult spinal deformity (ASD); however, we currently have unresolved new issues, including occasional anterior longitudinal ligament (ALL) rupture during the posterior correction procedure. When LLIF was initially introduced, only less lordotic cages were available and ALL rupture was more frequently experienced compared with later periods when more lordotic cages were available. We performed finite element analysis (FEA) regarding the mechanism of ALL rupture during a posterior correction procedure. Methods: A spring (which mimics ALL) was introduced at the location of ALL in the FEA and an LLIF cage with two different lordotic angles, 6 and 12 degrees (6DC/12DC), was employed. To assess the extent of burden on the ALL, the extension length of the spring during the correction procedure was measured and the location of the rotation center was examined. Results: We observed a significantly higher degree of length extension of the spring during the correction procedure in the FEA model with 6DC compared with that of 12DC. We also observed that the location of the rotation center was shifted posteriorly in the FEA model with 6DC compared with that of 12DC. Conclusions: It is considered that the posterior and rostral edge of the less lordotic angle cage became a hinge, and the longer lever arm increased the burden on ALL as the principle of leverage. It is important to use an LLIF cage with a sufficient lordotic angle, that is compatible with the degree of posterior osteotomy in ASD correction.

Biomechanical study of two-level oblique lumbar interbody fusion with different types of lateral instrumentation: a finite element analysis

Objective

The aim of this study was to verify the biomechanical properties of a newly designed angulated lateral plate (mini-LP) suited for two-level oblique lumbar interbody fusion (OLIF). The mini-LP is placed through the lateral ante-psoas surgical corridor, which reduces the operative time and complications associated with prolonged anesthesia and placement in the prone position.

Methods

A three-dimensional nonlinear finite element (FE) model of an intact L1-L5 lumbar spine was constructed and validated. The intact model was modified to generate a two-level OLIF surgery model augmented with three types of lateral fixation (stand-alone, SA; lateral rod screw, LRS; miniature lateral plate, mini-LP); the operative segments were L2-L3 and L3-L4. By applying a 500 N follower load and 7.5 Nm directional moment (flexion-extension, lateral bending, and axial rotation), all models were used to simulate human spine movement. Then, we extracted the range of motion (ROM), peak contact force of the bony endplate (PCFBE), peak equivalent stress of the cage (PESC), peak equivalent stress of fixation (PESF), and stress contour plots.

Results

When compared with the intact model, the SA model achieved the least reduction in ROM to surgical segments in all motions. The ROM of the mini-LP model was slightly smaller than that of the LRS model. There were no significant differences in surgical segments (L1-L2, L4-L5) between all surgical models and the intact model. The PCFBE and PESC of the LRS and the mini-LP fixation models were lower than those of the SA model. However, the differences in PCFBE or PESC between the LRS- and mini-LP-based models were not significant. The fixation stress of the LRS- and mini-LP-based models was significantly lower than the yield strength under all loading conditions. In addition, the variances in the PESF in the LRS- and mini-LP-based models were not obvious.

Conclusion

Our biomechanical FE analysis indicated that LRS or mini-LP fixation can both provide adequate biomechanical stability for two-level OLIF through a single incision. The newly designed mini-LP model seemed to be superior in installation convenience, and equally good outcomes were achieved with both LRS and mini-LP for two-level OLIF.

Establishing a Standardized Clinical Consensus for Reporting Complications Following Lateral Lumbar Interbody Fusion

Background and Objectives: Mitigating post-operative complications is a key metric of success following interbody fusion. LLIF is associated with a unique complication profile when compared to other approaches, and while numerous studies have attempted to report the incidence of post-operative complications, there is currently no consensus regarding their definitions or reporting structure. The aim of this study was to standardize the classification of complications specific to lateral lumbar interbody fusion (LLIF). Materials and Methods: A search algorithm was employed to identify all the articles that described complications following LLIF. A modified Delphi technique was then used to perform three rounds of consensus among twenty-six anonymized experts across seven countries. Published complications were classified as major, minor, or non-complications using a 60% agreement threshold for consensus. Results: A total of 23 articles were extracted, describing 52 individual complications associated with LLIF. In Round 1, forty-one of the fifty-two events were identified as a complication, while seven were considered to be approach-related occurrences. In Round 2, 36 of the 41 events with complication consensus were classified as major or minor. In Round 3, forty-nine of the fifty-two events were ultimately classified into major or minor complications with consensus, while three events remained without agreement. Vascular injuries, long-term neurologic deficits, and return to the operating room for various etiologies were identified as important consensus complications following LLIF. Non-union did not reach significance and was not classified as a complication. Conclusions: These data provide the first, systematic classification scheme of complications following LLIF. These findings may improve the consistency in the future reporting and analysis of surgical outcomes following LLIF.

Oblique lumbar interbody fusion versus minimally invasive transforaminal lumbar interbody fusion for the treatment of degenerative disease of the lumbar spine: a systematic review and meta-analysis

This meta-analysis compared the efficacy of oblique lumbar interbody fusion (OLIF) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in the treatment of lumbar degenerative diseases. A computer search for the published literature on OLIF and MIS-TLIF for the treatment of lumbar degenerative diseases in the PubMed, Web of Science, Embase, CINAHL, MEDLINE, Cochrane Library, and other databases was performed, from which 522 related articles were retrieved and 13 were finally included. Two reviewers independently extracted data from the included studies and analyzed them using RevMan 5.4. The quality of the studies was assessed using the Cochrane systematic analysis and the Newcastle-Ottawa scale. Meta-analysis showed that the blood loss [95% confidence intervals (CI) (- 121.01, - 54.56), [Formula: see text]], hospital stay [95% CI (- 1.98, - 0.85), [Formula: see text]], postoperative fusion rate [95%CI (1.04, 3.60), [Formula: see text]], postoperative disc height [95% CI (0.50, 3.63), [Formula: see text]], and postoperative foraminal height [95% CI (0.96, 4.13), [Formula: see text]] were all better in the OLIF group; however, the complication rates were significantly lower in the MIS-TLIF group [95% CI (1.01, 2.06), [Formula: see text]]. However, there were no significant differences between the two in terms of surgery time, patient satisfaction, or postoperative functional scores. The OLIF group had the advantages of lower blood loss, a shorter hospital stay, a higher postoperative fusion rate, and better recovery of the disc and foraminal heights, whereas MIS-TLIF had a relatively lower complication rate.

Hybrid surgery of percutaneous transforaminal endoscopic surgery (PTES) combined with OLIF and anterolateral screws rod fixation for treatment of multi-level lumbar degenerative diseases with intervertebral instability

BACKGROUND

Oblique lumbar interbody fusion (OLIF) has been used to treat lumbar intervertebral instability, which has some advantages including less trauma, less blood loss, faster recovery and bigger cage. However, it usually needs posterior screws fixation for biomechanical stability, and possible direct decompression for relieving neurologic symptoms. In this study, OLIF and anterolateral screws rod fixation through mini-incision were combined with percutaneous transforaminal endoscopic surgery (PTES) for the treatment of multi-level lumbar degenerative diseases (LDDs) with intervertebral instability. The purpose of study is to evaluate the feasibility, efficacy and safety of this hybrid surgery.

METHODS

From July 2017 to May 2018, 38 cases of multi-level LDDs of disc herniation, foramen stenosis, lateral recess stenosis or central canal stenosis with intervertebral instability and neurologic symptoms undergoing one-stage PTES combined with OLIF and anterolateral screws rod fixation through mini-incision were recruited in this retrospective study. The culprit segment was predicted according to the position of patient's leg pain and PTES under local anesthesia was performed for the culprit segment in the prone position to enlarge the foramen, remove the flavum ligamentum and herniated disc for the lateral recess decompression and expose bilateral traversing nerve roots for the central spinal canal decompression through an unilateral incision. During the operation, communicate with the patients to confirm the efficacy using VAS. And then mini-incision OLIF using allograft, autograft bone harvested in PTES and anterolateral screws rod fixation were performed in the right lateral decubitus position under general anesthesia. Back and leg pain were preoperatively and postoperatively evaluated using VAS. And the clinical outcomes were evaluated with ODI at the 2-year follow-up. The fusion status was assessed according to Bridwell's fusion grades.

RESULTS

There were 27 cases of 2-level, 9 cases of 3-level and 2 cases of 4-level LDDs with single-level instability on the X-ray, CT and MRI. Five cases of L3/4 instability and 33 cases of L4/5 instability were included. PTES was performed for 1 segment of 31 cases (25 cases of instability segment, 6 cases of no instability segment) and 2 segments including instability segment of 7 cases. Then, all instability segments were treated using mini-incision OLIF and anterolateral screws rod fixation. The average operation duration was 48.9 ± 7.3 min per level for PTES and 69.2 ± 11.6 min for OLIF and anterolateral screws rod fixation. The mean frequency of intraoperative fluoroscopy was 6 (5-9) times per level for PTES and 7 (5-10) times for OLIF. There was a mean blood loss of 30 (15-60) ml, and the incision length was 8.1 ± 1.1 mm for PTES and 40.0 ± 3.2 mm for OLIF. The mean hospital stay was 4 (3-6) days. The average follow-up duration was 31.1 ± 4.0 months. For the clinical evaluation, the VAS pain index and the ODI showed excellent outcomes. Fusion grades based on the Bridwell grading system at 2-year follow-up were grade I in 29 segments (76.3%) and grade II in 9 segments (23.7%). One patient encountered nerve root sleeves rupture during PTES and did not confront cerebrospinal fluid leakage or other abnormal clinical symptoms. There were two cases of hip flexion pain and weakness, which was relieved during 1 week after surgery. No patients had any form of permanent iatrogenic nerve damage and a major complication. No failure of instruments was observed.

CONCLUSIONS

The hybrid surgery of PTES combined with OLIF and anterolateral screws rod fixation is a good choice of minimally invasive surgery for multi-level LDDs with intervertebral instability, which can get direct neurologic decompression, easy reduction, rigid fixation and solid fusion, and hardly destroy the paraspinal muscles and bone structures.

Percutaneous transforaminal endoscopic surgery combined with mini-incision OLIF and anterolateral screws rod fixation vs. MIS-TLIF for surgical treatment of single-level lumbar spondylolisthesis

Objective

Oblique lumbar interbody fusion (OLIF) has been used to treat lumbar spine spondylolisthesis. However, it usually needs posterior pedicle screws fixation for biomechanical stability and possible posterior direct decompression for relieving neurologic symptoms. We use percutaneous transforaminal endoscopic surgery (PTES) combined with mini-incision OLIF and anterolateral screws rod fixation for surgical treatment of lumbar spondylolisthesis. The purpose of study is to evaluate the feasibility, efficacy, and safety of this method compared with minimally invasive surgery-transforaminal lumbar interbody fusion (MIS-TLIF).

Methods

From July 2016 to May 2018, 65 patients of lumbar spondylolisthesis (L2-4) with neurologic symptoms were treated using PTES combined with mini-incision OLIF and anterolateral screws rod fixation (31 cases, group A) or MIS-TLIF (34 cases, group B) in this study. Operative duration, blood loss, incision length, fluoroscopy frequency, and hospital stay are compared. Preoperative and postoperative visual analog scale (VAS) pain scores of back and legs, Oswestry disability index (ODI), intervertebral space height, lumbar lordotic angle, operative segmental lordotic angle, and complications are recorded. The fusion status is assessed according to Bridwell's fusion grades.

Results

The VAS score of back and leg pain and ODI significantly dropped after surgery in both groups (p < 0.001). There was no statistical difference of back and leg VAS score and ODI between two groups except that back VAS scores in group A were significantly lower than that of group B immediately after surgery (p = 0.000). Group A had significantly more intervertebral space height and operative segmental lordotic angle than group B postoperatively (p = 0.022, p = 0.002). Twenty-three segments (74.2%) were grade I and 8 segments (25.8%) were grade II in group A; 20 segments (58.8%) were grade I and 14 segments (41.2%) were grade II in group B at a 2-year follow-up (p = 0.194). No difference was observed in the complication rate between the two groups (6.5% vs. 5.9%, p = 0.924).

Conclusion

The long-term clinical efficacy and complication rates of both groups are comparable. PTES combined with mini-incision OLIF and anterolateral screws rod fixation is a good choice of minimally invasive surgery for lumbar spondylolisthesis, which hardly destroys the paraspinal muscles and bone structures.

Comparison of transfacet and pedicle screws in oblique lateral interbody fusion for single-level degenerative lumbar spine diseases: a retrospective propensity score-matched analysis

BACKGROUND

To perform a comparative assessment of percutaneous transfacet screws (TFS) and percutaneous bilateral pedicle screws (BPS) in oblique lateral interbody fusion (OLIF) for the treatment of single-level degenerative lumbar spine diseases in terms of radiological examinations and clinical outcomes.

METHODS

Sixty-six patients who received single-level OLIF with percutaneous supplementary fixation assisted by the robot for the treatment of degenerative lumbar spine diseases were selected. There were 16 cases of OLIF with TFS and 50 cases of OLIF with BPS. The propensity score matching method selected 11 patients in each group with matched characteristics to perform a clinical comparison.

RESULTS

The estimated blood loss was 68.2 ± 25.2 ml in the OLIF with TFS group compared to 113.6 ± 39.3 ml in the OLIF with BPS group (P < 0.05). The intervertebral disc height raised from 8.6 to 12.9 mm in the TFS group and from 8.9 to 13.9 mm in the BPS group in the immediate postoperative period, and dropped to 10.8 and 12.9 mm at the twelfth month, respectively (P < 0.05). The fusion rates were 91% and 100% for TFS and BPS groups (P > 0.05). Quantitative assessments of back/leg pain of the two groups reached a healthy level in the late period of the follow-up.

CONCLUSION

Both TFS and BPS techniques for the OLIF surgery relieve back pain caused by degenerative lumbar spine diseases. The TFS technique exhibits less blood loss compared with the BPS. A moderate cage subsidence is present in TFS but no complication is reported.

Small Preoperative Dural Sac Cross-Sectional Area and Anteriorly Placed Fusion Cages Are Risk Factors for Indirect Decompression Failure after Oblique Lateral Interbody Fusion

OBJECTIVE

1) To investigate if implant-related factors such as cage size and cage position are associated with radiologic improvement after indirect decompression with oblique lateral interbody fusion (OLIF). 2) To investigate the risk factors associated with indirect decompression failure (IDF) at the surgical levels after OLIF.

METHODS

From February 2015 to December 2019, 92 consecutive patients (188 levels) with lumbar spinal stenosis who underwent indirect decompression via OLIF with or without posterior instrumentation were studied retrospectively. Radiographic variables were measured preoperatively and postoperatively. The radiographic results were compared for cages with different heights and positions. IDF was defined as revision surgery within 6 months or persistent compressive symptoms 6 months after surgery.

RESULTS

Postoperative improvements were observed in all measured radiographic parameters except for segmental lordosis. Taller cages were associated with more shrinkage of the bulging disc and greater increase in dural sac diameter. Cages placed posteriorly showed larger postoperative subarticular diameters. Twelve patients (16 levels) had IDF. Multivariate logistic regression showed that after adjusting for age, sex, and body mass index, smaller preoperative dural sac cross-sectional area and anterior positioning of cages were both independent risk factors for IDF.

CONCLUSIONS

OLIF is an effective procedure for indirect decompression. To avoid reoperation for lumbar spinal stenosis, surgeons should aim to place the center of the cage at the posterior half of the lower endplate. Surgical levels with a preoperative dural sac cross-sectional area <44 mm2 may not be suitable for indirect decompression.

Oblique Lateral Endoscopic Decompression and Interbody Fusion for Severe Lumbar Spinal Stenosis: Technical Note and Preliminary Results

OBJECTIVE

Adequacy of decompression for oblique lateral interbody fusion (OLIF) is a real concern in patients with severe lumbar spinal stenosis (LSS). With this in mind, we combined OLIF with spinal endoscopic technique to achieve a solid fusion and an adequate decompression after one operation.

METHODS

This is a technical note. The theoretical basis and operation process of this technique were introduced, and consecutive cases were retrospectively collected. Consecutive patients diagnosed with monosegmental severe LSS (L4/5) and underwent oblique lateral endoscopic decompression and interbody fusion (OLEDIF) from January 2018 to February 2020 were retrospectively collected. Clinical outcomes were assessed by claudication distance, Visual Analog Scale (VAS), and Oswestry Disability Index (ODI) scores. Secondary indicators included operation time, operative blood loss, and postoperative complications.

RESULTS

Ten patients were selected for the OLEDIF procedure. They were five women and five men ranging in age from 49 to 75 years (mean age of 63.9 years) and in BMI from 25.4 to 30.2 kg/m² (mean BMI of 27.5 kg/m² ). The preoperative claudication distance was 160.00 ± 68.96 m (range 70-250 m), which was significantly extended on the 3-month and 1-year follow-up (1020.00 ± 407.70 m and 1040.00 ± 416.87 m, respectively). The preoperative VAS score of back pain and radiating leg pain was 5.50 ± 0.97 (range 4-7) and 6.40 ± 0.97 (range 5-8). The score on postoperative month 3 was 1.60 ± 0.52 (range 1-2) and 1.20 ± 0.79 (range 0-2), and the 1-year follow-up score was 1.90 ± 0.74 (range 1-3) and 1.60 ± 0.70 (range 1-3), respectively. The preoperative ODI was 72.23 ± 6.30 (range 64.4-82.2), the 3-month follow-up ODI was 31.12 ± 4.20 (range 24.4-35.6), and the 1-year follow-up ODI was 29.33 ± 5.92 (range 20.0-37.8). Compared with the transforaminal lumbar interbody fusion (TLIF) in the literature, the operation time was not prolonged (189.3 ± 32.5 min vs. 214.9 ± 60.0 min) but the amount of blood loss decreased significantly (113.3 ± 26.7 ml vs. 366.8 ± 298.2 ml). No complications were found except one case presented with dysesthesia of the left leg. Imaging results showed good fusion without cage subsidence during 1-year follow-up.

CONCLUSION

OLEDIF can achieve complete ventral decompression of the spinal canal and solid fusion of the lumbar spine at one time. It is an effective minimally invasive technique for the treatment of monosegmental severe LSS, which is promising and worthy of further clinical practice.

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.

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 versus Transforaminal Lumbar Interbody Fusion in Degenerative Spondylolisthesis: A Systematic Review and Meta-analysis

BACKGROUND: This meta-analysis compared transforaminal interbody fusion (TLIF) and oblique lumbar interbody fusion (OLIF) techniques for degenerative lumbar spondylolisthesis. AIM: The aim is to evaluate Oswestry Disability Index (ODI), Japanese Orthopedic Association Back Pain Evaluation Questionnaire, visual analog scale improvement for back and leg pain, disc height, slipped percentage, blood loss, surgical time, and complication rates in both groups. METHODS: A systematic literature search was carried out to obtain a study that compared OLIF and TLIF for degenerative lumbar spondylolisthesis. A literature search was performed using PubMed, Scopus, EuropePMC, and EBSCOHost. While the intervention was the OLIF technique, the control was the TLIF technique. The primary outcome was clinical outcome (ODI, Japanese Orthopaedic Association Back Pain Evaluation Questionnaire [JOABPEQ], visual analog scale [VAS] improvement for back, and leg pain). The Newcastle-Ottawa Scale was used to assess the quality of the studies. RESULTS: Total of 384 patients from four studies were included in this study. OLIF group was better than TLIF group in terms of disc height, slipped percentage, and blood loss. ODI, JOABPEQ, VAS improvement for back pain (standardized mean difference [SMD] 0.06 [−0.18, 0.29], p = 0.63, I2 = 0%, p = 0.87) and leg pain (SMD 0.12 [−0.36, 0.60], p = 0.63, I2 = 74%, p = 0.02), surgical time, and complication rates were similar in both groups. CONCLUSION: OLIF technique was better than TLIF technique in terms of radiologic outcome and surgical blood loss. Both techniques showed similar outcomes in clinical outcome, complication, and surgical time.

Effects and Safety of Lumbar Fusion Techniques in Lumbar Spondylolisthesis: A Network Meta-Analysis of Randomized Controlled Trials

STUDY DESIGN

Network meta-analysis of randomized controlled trials.

OBJECTIVES

Lumbar spondylolisthesis is a common indication for spinal fusion. Lumbar interbody fusion (LIF) is popular method to achieve arthrodesis, but previous syntheses usually used head-to-head comparison of 2 surgical methods, and no of them pooled analysis with high-quality. This network meta-analysis of randomized controlled trials was carried out to simultaneously compare fusion techniques in the treatment of lumbar spondylolisthesis.

METHODS

Three databases were searched for randomized controlled trials (RCTs) on this topic. After critical appraisal, fusion rate, overall adverse events, operative time, Oswestry Disability Index, and pain were extracted for analysis. We conduced network meta-analysis using contrast-based method. Primary outcomes were reported as risk ratio (RR) with 95% confidence interval (CI).

RESULTS

Fifteen RCTs (n = 992) met our eligibility criteria. The RCTs treated patients posterolateral fusion (PLF), posterior LIF (PLIF), transforaminal LIF (TLIF), minimally invasive (MIS) TLIF, extreme lateral LIF (XLIF), and circumferential fusion. The pooled estimate showed that circumferential fusion led to significantly higher fusion rate than PLF (RR = 2.15, 95%CI:1.41-3.28), PLIF (RR = 2.11, 95%CI:1.38-3.22), TLIF (RR = 2.13, 95%CI:1.39-3.27), MIS-TLIF (RR = 2.13, 95%CI:1.35-3.35), and XLIF (RR = 2.01, 95%CI: 1.25-3.22). Moreover, circumferential fusion exhibited the best balance in probability between fusion rate and adverse event rate. No evidence showed inconsistency or small-study effect in the results.

CONCLUSIONS

Collectively, circumferential fusion might be worth to be recommended because it exhibits the best balance between fusion rate and overall adverse event. PLF is still an inferior procedure and requires shorter operative time.

Comparison of the clinical efficacy of two fixation methods combined with OLIF in the treatment of lumbar spondylolisthesis in adult patients

Background

To observe the clinical efficacy of an anterior single rob-screw fixation (ASRSF) combined with the oblique lumbar intervertebral fusion (OLIF) approach compared with a posterior percutaneous screw fixation (PPSF) combined with OLIF in the treatment of lumbar spondylolisthesis.

Method

This is a retrospective case–control study. Patients with degenerative lumbar spondylolisthesis (DLS) treated with either ASRSF combined with OLIF or PPSF combined with OLIF from January 2016 to January 2018 were enrolled in this study. None of the patients had posterior decompression. The visual analog scale (VAS) and Oswestry dysfunction index (ODI) were used for clinical efficacy assessment. The pre- and post-operational disc height, height of foramen, subsidence, and migration of cages, fusion rate and surgery-related complications were compared between the two groups.

Results

Fifty-three patients were included in this single-center study. According to the fixation methods, patients were divided into the ASRSF group (group A, 25 cases) and the PPSF group (group B, 28 cases). There was no statistical difference in surgery-related complications between groups. There was a significant difference in the VAS score at one-week post-surgery (2.3 ± 0.5 vs. 3.5 ± 0.4, P = 0.01), and three months post-operation (2.2 ± 0.3 vs. 3.0 ± 0.3, P = 0.01). Comparison of post-operative imaging data showed that there was a significant difference in the height of the foramen between groups at three months post-surgery(18.1 ± 2.3 mm vs. 16.9 ± 1.9 mm, P = 0.04). At 24 months post-surgery, the ODI was 12.65 ± 3.6 in group A and 19.1 ± 3.4 in group B (P = 0.01). Twelve months after surgery, the fusion rate in group A at 72.0% and 78.6% in group B was not statistically significant (P = 0.75). Fusion was identified in all patients at 24 months post-surgery.

Conclusion

When compared to PPSF, ASRSF combined with OLIF for DLS can reduce post-operative low back pain in the initial stages, maintain the height of the foramen and improve the performance of lumbar function.

Biomechanical Evaluation and Preliminary Clinical Results of Anterolateral Screw Fixation for Oblique Lumbar Interbody Fusion Surgery

BACKGROUND

The most common complication of oblique lumbar interbody fusion (OLIF) is endplate fracture/subsidence. The aim of this study was to evaluate biomechanical stability in patients undergoing OLIF surgery with anterolateral screw fixation (ASF).

METHODS

Based on a previously validated model technique, L4-L5 functional surgical models corresponding to the ASF and bilateral pedicle screw fixation (BPSF) methods were created. Finite element models were developed to compare the biomechanics of the ASF and BPSF groups. We retrospectively analyzed 18 patients with lumbar degenerative diseases who underwent OLIF with ASF in Shenzhen Hospital of Southern Medical University from April 2020 to April 2021. Intraoperative and postoperative complications were observed.

RESULTS

Compared with the BPSF model, the maximum stresses of the L4 inferior endplate and L5 superior endplate were greatly increased in the ASF model. The contact surface between the vertebrae and screw (CSVS) in the ASF model produced nearly 100% more stress than the BPSF model at all moments. In clinical practice, after a 12-month follow-up, 7 adverse events were observed, including 3 cases of left thigh pain/numbness, 3 cases of cage subsidence, and 1 case of screw loosening.

CONCLUSIONS

OLIF surgery with ASF could not reduce the maximum stresses on the endplate and CSVS, which may be a potential risk factor for cage subsidence and screw loosening.

An Anatomical Clue for Minimizing Iliac Vein Injury During the Anterolateral Approach at L5-S1 Level: A Cadaveric Study

Objective

The injury to the common iliac vein (CIV) seems to be the most important concern during the anterior approach to the spine at L5–S1 level. We investigated the anatomy of the L5–S1 vertebral structures related to the CIV through a cadaveric study to find an anatomical clue for safe dissection of CIV.

Methods

Ten cadavers were prepared for this study. After removing the peritoneum and the presacral fascia, the section from the lower part of the L5 to the upper part of the S1 vertebral body was removed with the CIV attached. After decalcification, 2 sections in the vertical and horizontal directions were made for histological study.

Results

An adipose tissue layer was present between the intervertebral disc and CIV. The adipose tissue layer in 6 cadavers was thin, and in 3 of these cadavers, the CIV was attached to the vertebral body and the disc. In the other 4 cadavers, the CIV was clearly separated from the vertebral body and the disc by the intervening adipose tissue layer (IATL). Under the microscope, a thin layer surrounding the anterior longitudinal ligament, periosteum, and disc was observed, and we named this structure the ‘perivertebral membrane.’ The perivertebral membrane was attached to the CIV when there was no IATL, but a potential space was detected under the membrane.

Conclusion

There was a thin membrane, perivertebral membrane, between the CIV and L5–S1 disc. In cases with CIV adhesion to the disc due to the absence of IATL, the CIV may be mobilized indirectly through the perivertebral membrane.

Evolution of Complex Spine Surgery in Neurosurgery: From Big to Minimally Invasive Surgery for the Treatment of Spinal Deformity

Spinal instrumentation for adult spinal deformity dates back to the surgical correction of secondary complications from infectious processes, such as Pott's disease and poliomyelitis [1]. With the population aging at a longer life expectancy today, advanced degenerative spinal diseases and idiopathic scoliosis supersede as the most common causes of adult spinal deformity. Correction of the thoracolumbar malignment, specifically, has rapidly evolved with the burgeoning success of spinal instrumentation. The objective of this chapter is to review the metamorphosis of operative principles for adult thoracolumbar deformity, from aggressive osteotomies in the posterior bony elements to minimally invasive surgery (MIS) at the intervertebral disc space.

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.

Minimally invasive transforaminal lumbar interbody fusion versus oblique lateral interbody fusion for lumbar degenerative disease: a meta-analysis

BACKGROUND

Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and oblique lateral interbody fusion (OLIF) are widely used in the treatment of lumbar degenerative diseases. In the present study, a meta-analysis was conducted to compare the clinical and radiographic efficacy of these two procedures.

METHODS

A systematic literature review was performed, and the quality of retrieved studies was evaluated with the Newcastle-Ottawa Scale (NOS). Clinical outcomes, including operation time, intraoperative blood loss, improvement in Visual Analogue Scale (VAS), improvement in Oswestry Disability Index (ODI), Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) effectiveness rate and complications, in addition to radiographic outcomes, including restoration of disc height, disc angle, overall lumbar lordosis, fusion rate and subsidence, were extracted and input into a fixed or random effect model to compare the efficacy of MIS-TLIF and OLIF.

RESULTS

Seven qualified studies were included. Clinically, OLIF resulted in less intraoperative blood loss and shorter operation time than MIS-TLIF. Improvement of VAS for leg pain was more obvious in the OLIF group (P < 0.0001), whereas improvement of VAS for back pain (P = 0.08) and ODI (P = 0.98) as well as JOABPEQ effectiveness rate (P = 0.18) were similar in the two groups. Radiographically, OLIF was more effective in restoring disc height (P = 0.01) and equivalent in improving the disc angle (P = 0.18) and lumbar lordosis (P = 0.48) compared with MIS-TLIF. The fusion rate (P = 0.11) was similar in both groups, while the subsidence was more severe in the MIS-TLIF group (P < 0.00001).

CONCLUSIONS

The above evidence suggests that OLIF is associated with a shorter operation time (with supplementary fixation in the prone position) and less intraoperative blood loss than MIS-TLIF and can lead to better leg pain alleviation, disc height restoration and subsidence resistance. No differences regarding back pain relief, functional recovery, complications, disc angle restoration, lumbar lordosis restoration and fusion rate were found. However, due to the limited number of studies, our results should be confirmed with high-level studies to fully compare the therapeutic efficacy of MIS-TLIF and OLIF.

TRIAL REGISTRATION

PROSPERO ID:  CRD42020201903 .

Prognosis of Symptomatic Pseudarthrosis Observed at 1 Year After Lateral Lumbar Interbody Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study was to investigate the prognosis of symptomatic pseudarthrosis observed at 1 year after lateral lumbar interbody fusion (LLIF) surgery and to analyze the risk factors for persistent pseudarthrosis for 2 years postoperatively.

SUMMARY OF BACKGROUND DATA

Few articles have evaluated the prognosis of symptomatic pseudarthrosis following LLIF surgery.

METHODS

One hundred fifty-two patients with a minimum follow-up of 2 years were screened. Fusion status was assessed at 1 year postoperatively, and unfused segments were reevaluated at 2 years postoperatively. Dynamic x-rays and computed tomography images were acquired to evaluate the fusion status. Demographic data were evaluated to identify the risk factors associated with persistent pseudarthrosis. Clinical outcomes, including the visual analog scale (VAS) for back/leg pain and the Oswestry disability index (ODI), were evaluated preoperatively and at 1 and 2 years postoperatively.

RESULTS

Symptomatic pseudarthrosis was detected in 42 patients at 1 year postoperatively. Among them, 23 patients (54.8%) exhibited solid bony fusion 2 years postoperatively without further intervention. Fourteen patients (33.3%) showed asymptomatic pseudarthrosis, and the remaining five patients (11.9%) showed symptomatic pseudarthrosis. Multivariable analysis showed that diabetes (adjusted odds ratio [OR]: 2.817, P = 0.007), smoking (adjusted OR: 6.497, P = 0.008), and fusion at more than three levels (adjusted OR: 2.525, P = 0.031) were risk factors for persistent pseudarthrosis. Improvements in the VAS scores for back pain and ODI scores were significantly lower in the persistent pseudarthrosis group than in the final solid fusion group at 2 years postoperatively.

CONCLUSION

It is not necessary to intervene for all patients in whom symptomatic pseudarthrosis is detected at 1 year postoperatively because only 11.9% of them will show persistent symptomatic pseudarthrosis. However, early revision surgery should be considered when severe symptomatic pseudarthrosis associated with diabetes, smoking, and fusion at more than three levels is present.Level of Evidence: 4.

Oblique lateral interbody fusion to treat lumbar spinal stenosis in a patient with situs inversus totalis: a case report

Oblique lateral interbody fusion (OLIF) is a minimally invasive spinal surgery that is popular for lumbar degeneration and spinal deformity treatment because it causes minimal damage to the stability of the intervertebral structures. However, when encountering abnormal anatomical structures caused by situs inversus, surgical routes must be adjusted to avoid serious complications. A 42-year-old woman with lumbar spinal stenosis presented to our hospital. Preoperative X-ray and computed tomography indicated situs inversus totalis, with the abdominal aorta and inferior vena cava reversed. We established an appropriate surgical approach for OLIF via the right abdomen according to the characteristics of the anatomical structures. Postoperative X-rays showed adequate positioning of the interbody fusion cage and internal fixation screws. At the 3-month follow-up, the patient reported resolution of her symptoms. Vascular variations caused by situs inversus totalis can affect the course of OLIF. Understanding the unique anatomical structure in such patients is crucial for successful surgery and to avoid intraoperative complications.

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

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

Introducing V-Line as a New Strategy to Choose Surgical Corridor in Oblique Lumbar Interbody Fusion at the L5-S1 Segment

Purpose

A retrospective imaging study assessing the availability of oblique lumbar interbody fusion at the level of L5-S1 (OLIF51) and to choose ideal surgical corridor in OLIF51 by introducing V-line.

Methods

The axial views through the center of L5-S1 disc were reviewed. We adopt 18 mm as the width of the simulated surgical corridor. The midline of the surgical corridor is at the center of L5-S1 disc. According to the traction distance of the left iliac vein (LCIV) and psoas major (PM), we defined all the subjects as V (+) (traction-difficultly LCIV), V (-) (traction-friendly LCIV), P (+) (traction-difficultly PM), and P (-) (traction-friendly PM). V-line was defined as a straight line dividing equally the simulated surgical corridor. All cases were divided into 2 groups: The V-line (+) group, more than half of the LCIV region, is located in the ventral part of V-line; the V-line (-) group, more than half of the LCIV region, is located in the dorsal part of V-line. Multiple variables regressive analysis was conducted to analyze the independent risk factors of V-line (+).

Results

V-line (+) was found in 36 (38.7%) patients and V-line (-) in 57 (61.3%). Incidence of V (+) and P (+) was 35.4% (33/93) and 30.1% (28/93), respectively. 16.1% (15/93) subjects processed V (+) and P (+) at the same time. The independent risk factor of V-line (+) were gender of male (P = 0.034, OR: 12.152) and medial position of LCIV (P < 0.001, OR: 265.085). High iliac crest was a significant independent protective factor (P = 0.001, OR: 0.750).

Conclusions

Most patients were suitable for OLIF51. V-line could assess the injury risk of LCIV. For patients who are V-line (+), mainly among males having the LCIV near the midline or the iliac crest relatively low, a surgical corridor external to the LCIV should be taken into consideration.

Trans-isthmic pars interarticularis screw fixation under CT and fluoroscopic guidance: technical success and clinical outcome in patients with symptomatic low-grade lumbar isthmic lysis

OBJECTIVES

To assess the technical success of trans-isthmic screw fixation with simultaneous CT and fluoroscopic guidance in patients with symptomatic low-grade isthmic spondylolisthesis.

METHODS

Fifty patients (28 women and 22 men; mean age ± standard deviation: 50 years ± 18.9) presenting with symptomatic low back pain with isthmic spondylolisthesis refractory to medical management were treated by means of trans-isthmic pars interarticularis percutaneous screw fixation. The procedure was performed under local anesthesia with double CT and fluoroscopic guidance. Primary outcome was technical success of the procedure, which was assessed with a post-procedure CT using the same success criteria as surgical screw placement with regard to entry point, trajectory, and screw tip. Secondary outcome was pain decrease assessed by the Visual Analog Scale (VAS).

RESULTS

Ninety-nine procedures were performed in 50 patients and 99 screws were inserted. Postoperative CT assessment showed satisfactory screw placement in 96 cases, reflecting a technical success rate of 96.9%. No complications occurred during or after the procedure. Pain assessment showed a pain decrease of VAS score from a median of 7 (min 5, max 10; MAD 1.4) to 2 (p < 0.0001) (min 0, max 7, MAD 1.7) with a mean follow-up of 39 months.

CONCLUSION

Trans-isthmic screw fixation performed under CT and fluoroscopic guidance presents a high technical success and appears as a safe procedure and effective procedure in patients with symptomatic low-grade isthmic lysis.

KEY POINTS

• Trans-isthmic pars interarticularis percutaneous screw insertion is feasible under double CT and fluoroscopic guidance by a radiologist with a high technical success. • This technique can be performed under local anesthesia only. • In patients with chronic low back pain, isthmic screwing allows long-term pain improvement.

MRI-Based Morphometric Study Regarding Operative Windows of Oblique Lumbar Interbody Fusion in Indian Population

BACKGROUND

The novel Oblique lumbar interbody fusion [OLIF] technique has been proposed as a solution to approach related complications of anterior lumbar interbody fusion [ALIF] and lateral lumbar interbody fusion [LLIF]. There exists no study concerning morphological evaluation of retroperitoneal oblique corridor for the Oblique lumbar interbody fusion (OLIF) technique in the Indian population. The aim of our study was (a) to measure magnetic resonance imaging (MRI) based anatomic parameters concerning OLIF operative windows from L2-L3 to L4-L5 level (b) to determine the feasibility of this technique following MRI-based morphometric evaluation in the Indian population.

MATERIAL AND METHODS

We did retrospective MRI analysis of 307 consecutive patients following our exclusion criteria. Bare window, psoas major window and psoas major width were measured from axial T2 MRI image taken at mid disc level from L2-L3 to L4-L5 levels.

RESULTS

The mean bare window size was largest at L2-L3 (1.39 cm) level followed by L3-L4 and L4-L5 level (1.28 and 0.62 cm respectively), and differences between them were statistically significant (P < 0.001). Females had statistically significant larger bare windows at L2-L3 and L3-L4 level than males (P < 0.001). With increasing age, there was a significant increase in bare window size at each level (P < 0.001). The mean psoas major window (PM^O) and mean psoas major width (PM^I) were largest at L4-L5 level (PM^O = 1.27 cm, PM^I = 3.61 cm) followed by L3-L4 and L2-L3 level (L3-L4: PM^O = 1.19 cm, PM^I = 2.36 cm; L2-L3: PM^O = 0.88 cm, PM^I = 1.39 cm), and differences among each level concerning both parameters were statistically significant (P < 0.001). Both parameters (PM^O, PM^I) were significantly larger in males than females at each level (P < 0.001).

CONCLUSION

The OLIF technique is well suited for lumbar interbody fusion at L2 -L3 and L3-L4 level in the Indian population irrespective of age and sex. At L4-L5 level, overall 17.9 percent of the study population were unsuitable for this technique due to inaccessible bare window. In our opinion, this level may be better suited for OLIF approach in the elderly Indian population, especially for surgeons who are beginning to attempt this technique in their surgical practice. Preoperative MRI evaluation for the OLIF is important to assess its feasibility, as there exists significant age and gender differences in the Indian population for anatomic parameters concerning OLIF operative windows from L2-L3 to L4-L5 levels.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s43465-021-00393-7.

Continuous wound infiltration of ropivacaine for reducing of postoperative pain after anterior lumbar fusion surgery: a clinical retrospective comparative study

Background

Local anesthetic infiltration at the site of a surgical wound is commonly used to control postoperative pain. In this study, we examined the effectiveness of continuous local infiltration at an abdominal surgical site in patients undergoing anterior lumbar interbody fusion (ALIF) surgery.

Methods

Sixty-one patients who underwent ALIF surgery were enrolled. For thirty-one of them, a continuous local anesthetics infiltration system was used at the abdominal site. We collected data regarding the patients’ sleep quality; satisfaction with pain control after surgery; abilities to perform physical tasks and the additional application of opioids in the postoperative 48 hours.

Results

The On-Q system group showed reduced visual analogue scale scores for pain at the surgical site during rest and movement at 0, 12, 24, and 48 hours; and more was satisfied with pain control management at the first postoperative day (7.0 ± 1.2 vs. 6.0 ± 1.4; P = 0.003) and week (8.1 ± 1.6 vs. 7.0 ± 1.8; P = 0.010) than the control group. The number of additional patient-controlled analgesia (PCA) bolus and pethidine injections was lower in the On-Q group (PCA 3.67 ± 1.35 vs. 4.60 ± 1.88; P = 0.049 and pethidine 2.09 ± 1.07 vs. 2.73 ± 1.38; P = 0.032). Patients who used the On-Q system performed more diverse activity and achieved earlier ambulation than those in the control group.

Conclusions

Continuous wound infiltration with ropivacaine using an On-Q system may be effective for controlling postoperative pain after ALIF surgery.

Lateral-anterior lumbar interbody fusion (LaLIF) for lumbar degenerative disease: Technical notes, surgical system, and mid-term outcomes

Background

Many modified lateral lumbar interbody fusion techniques for lumbar degenerative diseases have been described by different authors. However, relatively high rates of vascular injury, peritoneal laceration, and even ureteral injury have been reported.

Purpose

The objectives of this study were firstly to present the detailed, standardized technical notes and describe the required standard characteristics of the designed surgical system of LaLIF and secondly to evaluate clinical outcomes and highlight the approach-related complications.

Methods

The mini-open LaLIF is described in a step-wise manner. The outcome measures were operative parameters, self-report measures, radiographic measures, and complications within 1 month of surgery. Operative parameters measured included operative time, intraoperative blood loss, and length of hospital stay. The self-report measures include Visual Analogue Scale (VAS), Oswestry disability index (ODI), and Short Form 36 Health Survey (SF-36) score. The radiographic measures including the intervertebral foraminal height (FH), intervertebral disc height (DH), and intervertebral foraminal area (FA) were assessed with plain radiography. The complication profiles were classified into intraoperative and postoperative (up to 1 month). Intraoperative complications were subcategorized into neurologic, vascular, ureteral, peritoneal, and vertebral injuries. Postoperative complications were subcategorized into infection, cage migration, and subsidence.

Results

A total of 126 patients who underwent LaLIF between April 2016 and December 2018 ​by a senior author were retrospectively reviewed. There were 54 males and 72 females (range 42–89 ​years old, average 65 ​± ​11 years old). The mean follow-up was 20 ​± ​11 ​months (range 6–38 ​months). The LaLIF was conducted at 188 levels in 126 patients, with 1 level in 75 cases, 2 levels in 42, 3 levels in 7, and 4 levels in 2 cases. There were 114 patients who underwent stand-alone LaLIF and 12 patients required secondary posterior fixation. The mean operative time, intraoperative blood loss, and length of hospital stay were recorded. The patient-reported outcome scores (VAS, ODI, and SF-36) and radiographic parameters (FH, DH, and FA) demonstrated a significant improvement after surgery and at the last follow-up. There were 25 (19.8%) complications in the 126 patients. The intraoperative complications accounted for 19 cases (15.1%) and postoperative accounted for 6 cases (4.8%). The most frequent complications were neurological injury (6.3%) and temporary psoas injury (6.3%).

Conclusions

The mini-open LaLIF, as a reproducible novel technique, can be performed safely at L2-L5. It is associated with reliable mid-term clinical outcomes and an acceptable complication profile when compared to traditional LLIF due to the advancements in the modified incision site, direct visualization, and usage of strictly vertical trajectory in multiple steps with the specially designed LaLIF system.

Translational potential statement

To make the lateral lumbar fusion process repeatable and also maintain a shallow learning curve, especially for surgeons in the early stages of learning, by using instruments with the required standard characteristics, the standardized surgical steps, modified incision site, vertical trajectory, and the direct visualization during the entire procedure.

Importance of the epiphyseal ring in OLIF stand-alone surgery: a biomechanical study on cadaveric spines

PURPOSES

To explore the function of endplate epiphyseal ring in OLIF stand-alone surgery using a biomechanical model to reduce the complications of endplate collapse and cage subsidence.

METHODS

In total, 24 human cadaveric lumbar function units (L1-2 and L3-4 segments) were randomly assigned to two groups. The first group was implanted with long fusion cages which engaged with both inner and outer regions of epiphyseal ring (Complete Span-Epiphyseal Ring, CSER). Those engaged with only the inner half of epiphyseal ring were the second group (Half Span-Epiphyseal Ring, HSER). Each group was divided into two subgroups [higher cage-height (HH) and normal cage-height (NH)]. Specimens were fixed in testing cups and compressed at approximately 2.5 mm/s, until the first sign of structural failure. Trabecular structural damage was analyzed by Micro-CT, as well as the difference of bone volume fraction (BV/TV), trabecular thickness (Tb.Th) et al. in different regions.

RESULTS

Endplate collapse was mainly evident in the inner region of epiphyseal ring, where trabecular injury of sub-endplate bone was most concentrated. Endplate collapse incidence was significantly higher in HSER than CSER specimens (P = 0.017). A structural failure occurred at a lower force in HSER (1.41 ± 0.34 KN) compared with CSER (2.44 ± 0.59 KN). HH subgroups failed at a lower average force than NH subgroups. Micro-CT results showed a more extensive trabecular fracture in HSER specimens compared to CSER specimens, especially in HH subgroup.

CONCLUSIONS

Endplate collapse is more likely to occur with short half span cages than complete span cages, and taller cages compared with normal height cages. During OLIF surgery, we should choose cages matching intervertebral disc space height and place the cages spanning over the whole epiphyseal ring to improve support strength.

Supine anterior lumbar interbody fusion versus lateral position oblique lumbar interbody fusion at L5-S1: A comparison of two approaches to the lumbosacral junction

INTRODUCTION

At L5-S1, anterior access can be performed with a supine anterior lumbar interbody fusion (ALIF) or lateral position oblique lumbar interbody fusion (LOLIF). We compared clinical and radiographic features of both approaches.

METHODS

A retrospective study of L5-S1 ALIF and LOLIF patients (2013-2018) by 3 spine surgeons and a vascular surgeon at our hospital was performed. Inclusion criteria were patients undergoing L5-S1 anterior surgery only without other anterior or lateral fusion levels, and data collected were patient demographics, cage parameters, perioperative variables, and radiographic parameters. 58 patients were included (33 ALIF and 25 LOLIF).

RESULTS

The average surgical time was 211.94 min for ALIF and 154.86 min for LOLIF (p < 0.001). The average blood loss was 214 ml for ALIF and 74 ml for LOLIF (p < 0.001). The average number of days to solid food was 2.55 for ALIF and 0.8 for LOLIF (p < 0.001). The average anterior L5-S1 disc height increase was 8.52 mm for ALIF and 5.02 mm LOLIF (p = 0.018), and the average posterior L5-S1 disc height increase was 3.34 mm for ALIF and 1.30 mm for LOLIF (p = 0.034). The average L5-S1 segmental lordosis increase was 6.82 degrees for ALIF and 7.63 degrees for LOLIF (p = 0.638).

CONCLUSION

The LOLIF is a feasible option for L5-S1 anterior access compared to ALIF. However, supine ALIF afforded larger cages to be placed, resulting in greater postoperative disc height. There did not appear to be a significant difference in postoperative L5-S1 segmental lordosis between the two approaches.

Anterior lumbar compared to oblique lumbar interbody approaches for multilevel fusions to the sacrum in adults with spinal deformity and degeneration

OBJECTIVE

In adult spinal deformity and degenerative conditions of the spine, interbody fusion to the sacrum often is performed to enhance arthrodesis, induce lordosis, and alleviate stenosis. Anterior lumbar interbody fusion (ALIF) has traditionally been performed, but minimally invasive oblique lumbar interbody fusion (OLIF) may or may not cause less morbidity because less retraction of the abdominal viscera is required. The authors evaluated whether there was a difference between the results of ALIF and OLIF in multilevel anterior or lateral interbody fusion to the sacrum.

METHODS

Patients from 2013 to 2018 who underwent multilevel ALIF or OLIF to the sacrum were retrospectively studied. Inclusion criteria were adult spinal deformity or degenerative pathology and multilevel ALIF or OLIF to the sacrum. Demographic, implant, perioperative, and radiographic variables were collected. Statistical calculations were performed for significant differences.

RESULTS

Data from a total of 127 patients were analyzed (66 OLIF patients and 61 ALIF patients). The mean follow-up times were 27.21 (ALIF) and 24.11 (OLIF) months. The mean surgical time was 251.48 minutes for ALIF patients and 234.48 minutes for OLIF patients (p = 0.154). The mean hospital stay was 7.79 days for ALIF patients and 7.02 days for OLIF patients (p = 0.159). The mean time to being able to eat solid food was 4.03 days for ALIF patients and 1.30 days for OLIF patients (p < 0.001). After excluding patients who had undergone L5-S1 posterior column osteotomy, 54 ALIF patients and 41 OLIF patients were analyzed for L5-S1 radiographic changes. The mean cage height was 14.94 mm for ALIF patients and 13.56 mm for OLIF patients (p = 0.001), and the mean cage lordosis was 15.87° in the ALIF group and 16.81° in the OLIF group (p = 0.278). The mean increases in anterior disc height were 7.34 mm and 4.72 mm for the ALIF and OLIF groups, respectively (p = 0.001), and the mean increases in posterior disc height were 3.35 mm and 1.24 mm (p < 0.001), respectively. The mean change in L5-S1 lordosis was 4.33° for ALIF patients and 4.59° for OLIF patients (p = 0.829).

CONCLUSIONS

Patients who underwent multilevel OLIF and ALIF to the sacrum had comparable operative times. OLIF was associated with a quicker ileus recovery and less blood loss. At L5-S1, ALIF allowed larger cages to be placed, resulting in a greater disc height change, but there was no significant difference in L5-S1 segmental lordosis.

The History of Anterior and Lateral Approaches to the Lumbar Spine

Anterior and lateral approaches to the lumbar spine are commonly used today for a variety of indications. These approaches can ultimately be traced back to early attempts to treat Pott's disease. Evidence of Mycobacterium tuberculosis infection of the spine dates as far back as 2400 BCE, with ancient Egyptian mummies exhibiting lesions consistent with Pott's disease. For many centuries, Pott's disease was treated conservatively, and surgery came to be used when conservative therapy was ineffective, as medical therapy had yet to become available. In 1779, Percivall Pott recommended that peripheral paraspinal tuberculous abscesses be drained after noticing that patients' lower limb function improved after the formation of spontaneous draining sinuses. Building on Pott's ideas, Ménard described the first lateral approach to the spine via a costotransversectomy approximately 1 century after Pott's theory. Most importantly, the surge in understanding anatomy with respect to developing safe corridors to the deeper structures of the human body brought together advances in technology, instrumentation, and visualization. Surgeons were thus emboldened to explore more complex anterior approaches to the spine. In 1906, Müller reported the first successful anterior approach to the spine in a patient with Pott's disease. Over the next several decades, the efforts of surgeons such as Ito, Capener, Burns, and Mercer would lead to the development of the anterior lumbar interbody fusion. The costotransversectomy later evolved into the lateral rhachotomy and lateral extracavitary approach, which along with advances in the anterior lumbar interbody fusion paved the way for the oblique lumbar interbody fusion and lateral lumbar interbody fusion.

Neutral hip position for the oblique lumbar interbody fusion (OLIF) approach increases the retroperitoneal oblique corridor

BACKGROUND

The prepsoas lateral approach for spinal fusion, oblique lateral lumbar interbody fusion (OLIF), is considered one of the minimally invasive spinal fusion methods and is gaining popularity due to improved outcomes with copious supporting evidence. To date, no publication has studied the various positions of the left hip in actual patients which might affect the retroperitoneal oblique corridor (ROC). The study aimed to find the relevancy of the left hip position and the size of ROC.

METHODS

We recruited 40 consecutive patients who needed diagnostic MRI from the out-patient clinic. MRI scan from L2 to L5 was performed in the supine, right lateral decubitus with hip flexion, and right lateral decubitus with hip in a neutral position. The retroperitoneal oblique corridor (ROC) was measured at the intervertebral disc level and compared.

RESULTS

ROC of the hip in neutral position was significantly larger than hip flexion in all levels (p < 0.05); there was no significant difference in the ROC among levels (p = 0.22). ROC seems to be largest at L2/3 followed by L3/4 and L4/5 respectively in all positions.

CONCLUSIONS

The retroperitoneal oblique corridors of L2 to L5 were significantly increased when the hip is in the neutral position, while the psoas cross-sectional area and anterior thickness were minimized in this position. Surgeons might benefit from a neutral position of the left hip in the oblique lateral lumbar interbody fusion (OLIF) procedure. In conclusion, the retroperitoneal oblique corridors of L2 to L5 were significantly increased when the hip is in the neutral position, while the psoas cross-sectional area and anterior thickness were minimized in this position. Surgeons might benefit from a neutral position of the left hip in the oblique lateral lumbar interbody fusion procedure.

Correlation study of radiographic characteristics and operative difficulty in lateral-anterior lumbar interbody fusion (LaLIF) at the L4-5 level: a novel classification for case selection

PURPOSE

To analyze correlations between the realistic surgical difficulty of LaLIF and anatomic characteristics in radiographic images, in order to develop a simple classification to provide guiding information for case selection and evaluate the potential risks of the technique.

METHODS

Ninety-six consecutive cases who underwent LaLIF surgeries at the L4-5 level with MR T2-weighted images were analyzed. A novel classification based on the anatomic relationships among the disk, great vessels, and psoas muscle was used for grouping. Clinical outcomes and realistic surgical difficulty parameters were recorded, and comparisons were made among different types of classifications.

RESULTS

Of the 96 analyzed cases, the time of surgical exposure was significantly longer for type C than for type B, and both of these were longer than that of type A. The VAS and ODI were significantly improved at a 1-year follow-up. There was no statistically significant difference among the three types. Type C had the highest incidence of complications, while Type A had the lowest. Analyses of another 304 MRI cases obtained in outpatient clinics showed that the distribution of the three types among these cases was consistent with that of the surgical cohort.

CONCLUSION

Our novel and simple classification provides useful information for case selection. Type A provided the best indication and is most appropriate for a beginner in this technique. Type C includes the most challenging situations, which may have a high incidence of complications and require sophisticated surgical skills to achieve satisfactory outcomes and avoid approach-related complications.

A Comparison of Complications and Clinical and Radiologic Outcome Between the Mini-open Prepsoas and Mini-open Transpsoas Approaches for Lumbar Interbody Fusion: A Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To compare complication rates and clinical and radiologic outcome between the mini-open prepsoas and mini-open transpsoas approaches for lateral lumbar interbody fusion.

SUMMARY OF BACKGROUND DATA

Both approaches are believed to be safe with similar complication rates. Previous studies suggest that the rate of neurological injury might be higher in the transpsoas group, whereas visceral or vascular injury might be more frequent in the prepsoas group.

METHODS

A systematic review of the literature was performed. Data were extracted from original publications up until December 26, 2018. Evidence was extracted from well-designed case-control or cohort studies and sorted in 2 groups, the prepsoas and transpsoas approaches. A meta-analysis was performed using a random-effects model (I statistic >50% for all analyses).

RESULTS

A total of 115 studies included data of 13,260 patients, 2450 in the prepsoas group and 10,810 in the transpsoas group. Demographics for prepsoas versus transpsoas group were (N-weighted means): age 61.9 versus 60.9 years; %female sex 53% versus 63%, levels fused 1.4 versus 2.6, blood loss 52.4 versus 122.3 mL, and operating time 125.1 versus 200.7 min. The following statistically significant differences in complication rates between prepsoas and transpsoas approaches were found: transient psoas weakness or thigh/groin numbness 4% versus 26% [95% confidence interval (CI): 11%-17%], motor neural injury 0.4% versus 1.3% (95% CI: 16%-62.3%); no statistically significant differences were found for: major vascular injury 2% versus 1% (95% CI: 1.04%-2.31%), kidney or ureter injury 0.04% versus 0.08% (95% CI: 0.057%-5.2%), injury pleural/peritoneal structures 0.6% versus 0.2% (95% CI: 0.89%-6.58%), cage subsidence 5% versus 4% (95% CI: 0.9%-1.97%), surgical site infection 1% versus 1% (95% CI: 0.57%-1.66%), abdominal wall pseudohernia 1% versus 1% (95% CI: 0.07%-21.22%), sympathetic chain injury 5% versus 0% (95% CI: 0.34%-97.86%), and directly procedure-related death 0.04% versus 0% (95% CI: 0.127%-76.8%). Pooled mean perioperative changes between prepsoas and transpsoas approaches were: segmental sagittal Cobb angle 3.07 versus 1.99 degrees; foraminal height 2 versus 6.96 mm.

CONCLUSIONS

The prepsoas had fewer complications than the transpsoas approach. Furthermore, the prepsoas approach showed superior restoration of segmental lordosis, whereas foraminal height restoration was superior with the transpsoas approach. This could be explained by the differences in location of the interbody device placement in relation to the center of rotation of the spine between the 2 surgical techniques.

The effect of obesity on perioperative morbidity in oblique lumbar interbody fusion

OBJECTIVE

Obese patients have been shown to have longer operative times and more complications from surgery. However, for obese patients undergoing minimally invasive surgery, these differences may not be as significant. In the lateral position, it is thought that obesity is less of an issue because gravity pulls the visceral fat away from the spine; however, this observation is primarily anecdotal and based on expert opinion. The authors performed oblique lumbar interbody fusion (OLIF) and they report on the perioperative morbidity in obese and nonobese patients.

METHODS

The authors conducted a retrospective review of patients who underwent OLIF performed by 3 spine surgeons and 1 vascular surgeon at the University of California, San Francisco, from 2013 to 2018. Data collected included demographic variables; approach-related factors such as operative time, blood loss, and expected temporary approach-related sequelae; and overall complications. Patients were categorized according to their body mass index (BMI). Obesity was defined as a BMI ≥ 30 kg/m2, and severe obesity was defined as a BMI ≥ 35 kg/m2.

RESULTS

There were 238 patients (95 males and 143 females). There were no significant differences between the obese and nonobese groups in terms of sex, levels fused, or smoking status. For the entire cohort, there was no difference in operative time, blood loss, or complications when comparing obese and nonobese patients. However, a subset analysis of the 77 multilevel OLIFs that included L5-S1 demonstrated that the operative times for the nonobese group was 223.55 ± 57.93 minutes, whereas it was 273.75 ± 90.07 minutes for the obese group (p = 0.004). In this subset, the expected approach-related sequela rate was 13.2% for the nonobese group, whereas it was 33.3% for the obese group (p = 0.039). However, the two groups had similar blood loss (p = 0.476) and complication rates (p = 0.876).

CONCLUSIONS

Obesity and morbid obesity generally do not increase the operative time, blood loss, approach-related sequelae, or complications following OLIF. However, obese patients who undergo multilevel OLIF that includes the L5-S1 level do have longer operative times or a higher rate of expected approach-related sequelae. Obesity should not be considered a contraindication to multilevel OLIF, but patients should be informed of potentially increased morbidity if the L5-S1 level is to be included.

From clinic to hypothesis, an innovative operation for the treatment of lumbar spinal stenosis in a minimal invasive way

Concerning the damage to back muscles and posterior ligament complex (PLC) by posterior open approach for lumbar spinal stenosis (LSS), the oblique lateral intervertebral fusion (OLIF) is pretty popular nowadays. However, oblique lateral approach has obvious drawbacks, which are limited vision and operative scope for achieving spinal canal decompression. Herein, we present a hypothesis that lumbar canal decompression can be well achieved by OLIF combined with spinal endoscope operative system. Nerval decompression and spinal reconstruction are achieved in a minimal invasive way, which may play an instructive role for the treatment of serious LSS.