Differences in radiographic and clinical outcomes of oblique lateral interbody fusion and lateral lumbar interbody fusion for degenerative lumbar disease: a meta-analysis

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

STUDY DESIGN

Retrospective study.

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Lateral lumbar interbody fusion - clinical outcomes, fusion rates and complications with recombinant human bone morphogenetic protein-2

BACKGROUND

The authors report an Australian experience of lateral lumbar interbody fusion (LLIF) with respect to clinical outcomes, fusion rates, and complications, with recombinant human bone morphogenetic protein-2 (rhBMP-2) and other graft materials.

METHODS

Retrospective cohort study of LLIF patients 2011-2021. LLIFs performed lateral decubitus by four experienced surgeons past their learning curve. Graft materials classified rhBMP-2 or non-rhBMP-2. Patient-reported outcomes assessed by VAS, ODI, and SF-12 preoperatively and postoperatively. Fusion rates assessed by CT postoperatively at 6 and 12 months. Complications classified minor or major. Clinical outcomes and complications analysed and compared between rhBMP-2 and non-rhBMP-2 groups.

RESULTS

A cohort of 343 patients underwent 437 levels of LLIF. Mean age 67 ± 11 years (range 29-89) with a female preponderance (65%). Mean BMI 29kg/m2 (18-56). Most common operated levels L3/4 (36%) and L4/5 (35%). VAS, ODI and SF-12 improved significantly from baseline. Total complication rate 15% (53/343) with minor 11% (39/343) and major 4% (14/343). Ten patients returned to OR (2-wound infection, 8-further instrumentation and decompression). Most patients (264, 77%) received rhBMP-2, the remainder a non-rhBMP-2 graft material. No significant differences between groups at baseline. No increase in minor or major complications in the rhBMP-2 group compared to the non-rhBMP-2 group respectively; (10.6% vs 13.9% [p = 0.42], 2.7% vs 8.9% [p < 0.01]). Fusion rates significantly higher in the rhBMP-2 group at 6 and 12 months (63% vs 40%, [p < 0.01], 92% vs 80%, [p < 0.02]).

CONCLUSION

LLIF is a safe and efficacious procedure. rhBMP-2 in LLIF produced earlier and higher fusion rates compared to available non-rhBMP-2 graft substitutes.

Single position lateral lumbar interbody fusion with navigated percutaneous pedicle screw fixation: technique modification with resultant resource usage optimisation

Background

There is an increase in the volume of elective lumbar fusion surgeries. Various techniques have been described however the literature on cost comparisons of different fusion techniques is sparse. The aim of this study was to evaluate resource utilisation of single position (SP) lateral lumbar interbody fusion (LLIF) compared to dual position (DP) LLIF.

Methods

This retrospective study included all patients who underwent single-stage anterior to psoas (ATP) LLIF with navigated percutaneous pedicle screw (PPS) fixation by the senior author between September 2020 and September 2023. Demographic details, operative variables (duration of surgery, SP/DP) and complications (intra-operative, post-operative) were included. Variables related to resource usage included length of stay, implant fee, consumables fee, anaesthetist fee and facility fee.

Results

There were 6 patients in the SP group and 14 patients in the DP group. None of the patients had intra-operative complications. SP group was associated with a 44.6% decrease in the length of stay (P=0.023) compared to the DP group, holding CCI and levels constant. The median operative time for the SP and DP groups were 150 and 282.5 min respectively (P<0.001). The median consumables fee ($2,509 vs. $3,839, P<0.001) for the SP group were lower than the DP group.

Conclusions

SP LLIF with navigated PPS insertion described in this paper is a minimally invasive technique with reduced resource usage compared to DP LLIF.

Defining cage subsidence in anterior, oblique, and lateral lumbar spine fusion approaches: a systematic review of the literature

One of the most common complications of lumbar fusions is cage subsidence, which leads to collapse of disc height and reappearance of the presenting symptomology. However, definitions of cage subsidence are inconsistent, leading to a variety of subsidence calculation methodologies and thresholds. To review previously published literature on cage subsidence in order to present the most common methods for calculating and defining subsidence in the anterior lumbar interbody fusion (ALIF), oblique lateral interbody fusion (OLIF), and lateral lumbar interbody fusion (LLIF) approaches. A search was completed in PubMed and Embase with inclusion criteria focused on identifying any study that provided descriptions of the method, imaging modality, or subsidence threshold used to calculate the presence of cage subsidence. A total of 69 articles were included in the final analysis, of which 18 (26.1%) reported on the ALIF approach, 22 (31.9%) on the OLIF approach, and 31 (44.9%) on the LLIF approach, 2 of which reported on more than one approach. ALIF articles most commonly calculated the loss of disc height over time with a subsidence threshold of > 2 mm. Most OLIF articles calculated the total amount of cage migration into the vertebral bodies, with a threshold of > 2 mm. LLIF was the only approach in which most articles applied the same method for calculation, namely, a grading scale for classifying the loss of disc height over time. We recommend future articles adhere to the most common methodologies presented here to ensure accuracy and generalizability in reporting cage subsidence.

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.

Comparison between oblique lumbar interbody fusion and posterior lumbar interbody fusion for the treatment of lumbar degenerative diseases: a systematic review and meta-analysis

BACKGROUND

Although oblique lumbar interbody fusion (OLIF) has produced good results for lumbar degenerative diseases (LDDs), its efficacy vis-a-vis posterior lumbar interbody fusion (PLIF) remains controversial. This meta-analysis aimed to compare the clinical efficacy of OLIF and PLIF for the treatment of LDDs.

METHODS

A comprehensive assessment of the literature was conducted, and the quality of retrieved studies was assessed using the Newcastle-Ottawa Scale. Clinical parameters included the visual analog scale (VAS), and Oswestry Disability Index (ODI) for pain, disability, and functional levels. Statistical analysis related to operative time, intraoperative bleeding, length of hospital stay, lumbar lordosis angle, postoperative disc height, and complication rates was performed. The PROSPERO number for the present systematic review is CRD42023406695.

RESULTS

In total, 574 patients (287 for OLIF, 287 for PLIF) from eight studies were included. The combined mean postoperative difference in ODI and lumbar VAS scores was - 1.22 and - 0.43, respectively. In postoperative disc, height between OLIF and PLIF was 2.05. The combined advantage ratio of the total surgical complication rate and the mean difference in lumbar lordosis angle between OLIF and PLIF were 0.46 and 1.72, respectively. The combined mean difference in intraoperative blood loss and postoperative hospital stay between OLIF and PLIF was - 128.67 and - 2.32, respectively.

CONCLUSION

Both the OLIF and PLIF interventions showed good clinical efficacy for LDDs. However, OLIF demonstrated a superior advantage in terms of intraoperative bleeding, hospital stay, degree of postoperative disc height recovery, and postoperative complication rate.

Predictors of Vertebral Endplate Fractures after Oblique Lumbar Interbody Fusion

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Antepsoas Approaches to the Lumbar Spine

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

The efficacy and safety of low-molecular-weight heparin in patients undergoing knee arthroscopic surgery and anterior cruciate ligament reconstruction

Purpose

To inveatigate how effective LMWH was at preventing venous thromboembolism (VTE), major bleeding events, and minor bleeding events after simple knee arthroscopic surgery and anterior cruciate ligament reconstruction (ACLR).

Methods

We conducted a comprehensive search of PubMed, EMBASE, Cochrane Library, and the CNKI database for potentially eligible articles. The outcomes were evaluated in terms of odds ratio (OR) and the associated 95% confidence intervals (CIs). Meta-analysis was performed using the Stata software and subgroup analyses were performed based on the surgical setting including ACLR and simple knee arthroscopic surgery.

Results

A total of eight studies with 2249 patients and 1794 controls were included in this meta-analysis. In patients undergoing simple knee arthroscopic surgery, LMWH prophylaxis did not bring a significant reduction in the risk of symptomatic deep venous thrombosis (DVT), symptomatic pulmonary embolism (PE), symptomatic VTE, and did not increase the risk of major bleeding events, but did have a higher risk of minor bleeding events (OR = 1.95, 95% CI 1.34-2.84, P = 0.000) and a lower risk of asymptomatic DVT (OR = 0.14, 95% CI 0.04-0.53, P = 0.004) in comparison with non-LMWH prophylaxis. In patients undergoing ACLR, LMWH prophylaxis did not bring a significant reduction in the risk of symptomatic DVT, symptomatic PE, symptomatic VTE, and did not increase the risk of major bleeding events and minor bleeding events, but did have a lower risk of asymptomatic DVT (OR = 0.43, 95% CI 0.23-0.78, P = 0.006).

Conclusion

When compared to a control group, this meta-analysis found that LMWH had little potential benefit in preventing major VTE (symptomatic VTE, symptomatic DVT, and symptomatic PE) after simple knee arthroscopy and ACLR. As a result, LMWH should not be considered routinely in patients undergoing knee arthroscopic surgery.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Comparing clinical and radiological outcomes between single-level OLIF and XLIF: A systematic review and meta-analysis

Background Context

Oblique lumbar interbody fusion (OLIF) and extreme lateral interbody fusion (XLIF) are 2 popular minimally invasive spinal fusion techniques with unique approach-related complication profiles. Accordingly, patient-specific anatomical factors, such as vascular anatomy or iliac crest height, greatly influence which technique to use. Previous studies comparing these approaches do not account for the inability of XLIF to access the L5-S1 disc space and therefore do not exclude this level in their analysis. The purpose of this study was to compare radiological and clinical outcomes of these techniques in the L1-L5 region.

Methods

A query of 3 electronic databases (PubMed, CINAHL plus, and SCOPUS) was performed, without time restriction, to identify studies that evaluated outcomes of single-level OLIF and/or XLIF between L1 and L5. Based on heterogeneity, a random effects meta-analysis was performed to evaluate the pooled estimation of each variable between the groups. An overlap of 95% confidence intervals suggests no statistically significant difference at the p<.05 level.

Results

A total of 1,010 patients (408 OLIF, 602 XLIF) were included from 24 published studies. Improvements in disc height (OLIF: 4.2 mm; XLIF: 5.3 mm), lumbar segmental (OLIF: 2.3°; XLIF: 3.1°), and lumbar lordotic angles (OLIF: 5.3°; XLIF: 3.3°) showed no significant difference. The rate of neuropraxia was significantly greater in the XLIF group at 21.2% versus 10.9% in the OLIF group (p<.05). However, the rate of vascular injury was higher in the OLIF cohort at 3.2% (95% CI:1.7-6.0) as compared to 0.0 (95% CI: 0.0-1.4) in the XLIF cohort. Improvements in VAS-b (OLIF: 5.6; XLIF: 4.5) and ODI (OLIF: 37.9; XLIF: 25.6) scores were not significantly different between the 2 groups.

Conclusions

This meta-analysis demonstrates similar clinical and radiological outcomes between single-level OLIF and XLIF from L1 to L5. XLIF had significantly higher rates of neuropraxia, whereas OLIF had greater rates of vascular injury.

Establishing minimum clinically important difference for patient-reported outcome measures in patients undergoing lateral lumbar interbody fusion

BACKGROUND

The minimum clinically important difference (MCID) has not been established in lateral lumbar interbody fusion (LLIF). Our study aims to establish MCID for patient-reported outcome measures (PROMs) of physical function and pain for LLIF through anchor-based and distribution-based approaches.

METHODS

Patients undergoing LLIF with preoperative and 6-month postoperative Oswestry Disability Index (ODI) scores were identified. PROMs of Patient-Reported Outcome Measurement Information System Physical Function (PROMIS-PF), 12-Item Short Form Physical Component Score (SF-12 PCS), Veterans RAND 12-Item Short Form Physical Component Score (VR-12 PCS), visual analog scale (VAS) back, and VAS leg were collected at preoperative and 6-month postoperative time points. Anchor-based MCID calculations were average change, minimal detectable change, change difference, receiver operating characteristic curve, and cross-sectional analysis using ODI as the anchor. Distribution-based calculations were standard error of measurement, reliable change index, effect size, and 0.5 ∗ ΔSD.

RESULTS

Fifty patients were included. Anchor-based approaches MCID ranges were PROMIS-PF 1.1-9.6, SF-12 PCS 6.4-16.5, VR-12 PCS 5.9-12.9, VAS Back 1.4-4.6, and VAS Leg 1.3-4.3. The area under curve for receiver operating characteristics (ROC) analysis ranged from 0.63 to 0.71. Distribution-based MCID ranges were PROMIS-PF 1.4-4.5, SF-12 PCS 1.9-12.7, VR-12 PCS 2.0-6.6, VAS Back 0.4-1.4, and VAS Leg 0.5-2.0.

CONCLUSION

MCID thresholds varied widely depending on the calculation method. The closest to (0,1) ROC approach was the most clinically appropriate MCID calculation. The corresponding MCID values for LLIF were PROMIS-PF at 7.8, SF-12 PCS at 6.4, VR-12 PCS at 9.3, VAS Back at 4.6, and VAS Leg at 4.3.

Computational comparison of anterior lumbar interbody fusion and oblique lumbar interbody fusion with various supplementary fixation systems: a finite element analysis

BACKGROUND AND OBJECTIVE

Anterior lumbar interbody fusion (ALIF) and oblique lumbar interbody fusion (OLIF) have shown a great surgical potential, while it has always been controversial which surgical approach and which type of fixation system should be selected. This study investigated the biomechanical response of ALIF and OLIF with various supplementary fixation systems using the finite element method.

MATERIALS AND METHODS

Lumbar L4-L5 ALIF and OLIF models stabilized by different supplementary fixation systems (stand-alone cage, integrated stand-alone cage, anterior plate, and bilateral pedicle screw) were developed to assess the segmental range of motion (ROM), endplate stress (EPS), and screw-bone interface stress (SBIS).

EXPERIMENTAL RESULTS

ALIF showed lower ROM and EPS than OLIF in all motion planes and less SBIS in the most of motion planes compared with OLIF when the anterior plate or pedicle screw was used. ALIF induced higher ROM, while lower EPS and SBIS than OLIF in the majority of motion planes when integrated stand-alone cage was utilized. Using a stand-alone cage in ALIF and OLIF led to cage migration. Integrated stand-alone cage prevented the cage migration, whereas caused significantly larger ROM, EPS, and SBIS than other fixation systems except for the rotation plane. In the most of motion planes, the pedicle screw had the lowest ROM, EPS, and SBIS. The anterior plate induced a slightly larger ROM, EPS, and SBIS than the pedicle screw, while the differences were not significant.

CONCLUSION

ALIF exhibited a better performance in postoperative segmental stability, endplate stress, and screw-bone interface stress than OLIF when the anterior plate or the pedicle screw was used. The pedicle screw could provide the greatest postoperative segmental stability, less cage subsidence incidence, and lower risk of fixation system loosening in ALIF and OLIF. The anterior plate could also contribute to the stability required and fewer complications, while not as effectively as the pedicle screw. Extreme caution should be regarded when the stand-alone cage is used due to the risk of cage migration. The integrated stand-alone cage may be an alternative method; however, further optimization is needed to reduce complications and improve postoperative segmental stability.

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

Background

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

Methods

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

Results

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

Conclusions

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

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

Long-Term Clinical and Imaging Results of Oblique Lateral Interbody Fusion for Degenerative Lumbar Spondylolisthesis: A Systematic Review and Meta-Analysis

The efficacies and safety of oblique lateral interbody fusion (OLIF) for degenerative lumbar spondylolisthesis (DLS) remains controversial, and long-term clinical efficacies in particular need to be explored. This study is designed accordingly, therefore, we searched PubMed, Embase, Scopus, Web of Science, Cochrane Library, ProQuest, OVID, and SinoMed for literature, regardless of publication date or language. Taking 12 months after operation as the shortest limit, the outcome measures were extracted, including visual analog scale (VAS), Oswetry dysfunction index (ODI), Japanese Orthopaedic Association (JOA) score, intervertebral disk height (IDH), foraminal height (FH), lumbar lordosis (LL), segment lordosis (SL), slip ratio, and incidence of surgical complications. Meta-analysis was performed by RevMan 5.4 and Stata 16.0, and results were expressed with MD and 95% CI, and two-sided p-values with p < 0.05 being statistically significant. In total, 17 clinical studies (n = 689 patients) were screened, with an average patient age of 63.4 years. Our study revealed that VAS decreased by 4.55 (low back pain) and 5.46 (leg pain) points, respectively. And ODI score decreased by an average of 33.82% while JOA score increased by an average of 11.56 points. In terms of imaging indicators, mean IDH and FH increased by 4.18 and 4.91 mm, mean LL and SL improved by 9.22° and 2.46°, respectively. Besides, mean slip ratio decreased by 10.45%. The incidence of complications was statistically analyzed in 18 studies, with a rate of 4%-54% and an overall incidence of 19%. To sum up, our study was the first to focus on the long-term efficacies of OLIF treatment for DLS, and to provide further clinical evidence. However, long-term follow-up multicenter randomized controlled trials are still needed for further evaluation.

Psoas weakness following oblique lateral interbody fusion surgery: a prospective observational study with an isokinetic dynamometer

BACKGROUND CONTEXT

Although the surgical corridor used for oblique lateral interbody fusion (OLIF) protects the intrapsoas nerves by causing minimal compression, transient weakness remains the most commonly reported postoperative complication.

PURPOSE

Using a dynamometer to evaluate how the hip flexor strength changes following OLIF.

STUDY DESIGN/SETTING

A prospective observational study.

PATIENT SAMPLE

Forty-six patients who underwent single or multi-level OLIF for lumbar spondylolisthesis.

OUTCOME MEASURES

Isokinetic dynamometer values (peak torque, total work, average power), visual analogue scale (VAS) scores for leg pain, hypoesthesia, subjective weakness of the left hip flexor muscle, Oswestry disability index, body mass index, bone mineral density, radiologic findings of the psoas muscle (cross-sectional area, Hounsfield unit (HU), fat portion grade), and psoas retraction time.

METHODS

The isokinetic muscle strength of the hip flexor was measured five times (preoperatively and postoperatively at 2 days, 1 week, 1 month, and 3 months) for both legs. The peak torque was defined as the postoperative strength of the left hip flexor muscles, and was compared to the preoperative baseline value. The strength of the left and right hip flexor muscles were also compared at each time point. For logistic regression analysis, when the peak torque was below the median value, it was defined as lower peak torque.

RESULTS

Up to 1 week after surgery, the strength of the left hip flexor muscle decreased significantly (paired difference in peak torque was 22.6%, p<.001). In the results of multivariate logistic regression analysis, diabetes (odds ratio [OR]=8.43, p=.020) and the HU of the psoas muscle (OR=0.916, p=.034) were associated with lower peak torque 1 week after surgery. From 1 month after surgery, postoperative weakness of the psoas muscle was not significant. In the questionnaire survey, subjective left hip flexion weakness was reported in 8.5% (4/47) of patients 1 week after surgery, and it remained in only 2.1% (1/47) of patients after 3 months of operation. The frequency of left anterior thigh pain and hypoesthesia decreased from 85.1% (40/47) at 1 week to 2.1% (1/47) at 3 months after surgery. The mean VAS score for left anterior thigh or groin pain decreased significantly at 1 month after surgery (PO2D: 4.04±1.84, PO1M: 1.67±1.10, p<.001).

CONCLUSIONS

Dynamometer measurement showed that psoas strength declined significantly up to 1 week after OLIF surgery. Patients with diabetes or lower HU of the psoas muscle showed delayed recovery from postoperative weakness of the psoas muscle. However, the weakness was insignificant from 1 month after surgery. At 3 months after surgery, the other psoas-related problems (left anterior thigh pain and hypoesthesia) also disappeared.

OLIF versus MI-TLIF for patients with degenerative lumbar disease: Is one procedure superior to the other? A systematic review and meta-analysis

PURPOSE

To compare the effectiveness and safety of oblique lateral interbody fusion (OLIF) and minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) for degenerative lumbar disease.

METHODS

We searched relevant studies in Embase, PubMed, Cochrane, and Web of Science databases comprehensively from inception to March 2022. The data were extracted from included studies, including operation indications, radiographic parameters, and clinical outcomes. Random or fixed-effects models were used in all meta-analyses according to the between-study heterogeneity.

RESULTS

In total, 30 studies, including 2,125 patients, were included in this meta-analysis. Our study found similar disk height, length of hospital stay, visual analog scale (VAS), and Oswestry disability index(ODI) between the two groups. However, the OLIF showed an advantage in restoring lumbar lordotic angle compared with MI-TLIF, with the pooled mean change of 17.73° and 2.61°, respectively. Additionally, the operative time and blood loss in the OLIF group appeared to be less compared with the MI-TLIF group. Regarding complications, the rates of the two groups were similar (OLIF 14.0% vs. MI-TLIF 10.0%), but the major complications that occurred in these two procedures differed significantly.

CONCLUSION

The results of disk height, length of hospital stay, VAS, and ODI between the OLIF and MI-TLIF groups were similar. And the OLIF was superior in restoring lumbar lordotic angle, operative time, and blood loss. However, the OLIF group's complication rate was higher, although not significantly, than that in the MI-TLIF group.

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.

Surgical Treatment for Degenerative Lumbar Disease With Neurologic Deficits: Comparison Between Oblique Lumbar Interbody Fusion and Posterior Lumbar Interbody Fusion

Objective

This study aimed to compare the radiological and clinical outcomes of oblique lumbar interbody fusion (OLIF) and posterior lumbar interbody fusion (PLIF) surgeries and to confirm the effects of additional partial laminectomy on the surgical outcomes of OLIF.

Methods

This retrospective study included 130 patients who underwent OLIF or PLIF for single-level fusion. Among them, 42 patients underwent PLIF and open pedicle screw fixation and 88 underwent OLIF and percutaneous pedicle screw fixation. In the OLIF group, 42 patients received additional neural decompression through partial laminectomy and discectomy (direct OLIF), whereas the remaining 46 patients did not (indirect OLIF). To measure the neurological deficits, the clinical outcomes were evaluated using a visual analog scale for back and leg pain and the Oswestry Disability Index. Radiologic outcomes were evaluated based on the disc and foraminal heights as well as the segmental lordotic and lumbar lordotic angles.

Results

The improvement in the clinical outcomes did not differ significantly among the 3 groups. Radiologically, the 2 OLIF groups showed statistically significant improvements in the disc and foraminal heights when compared with the PLIF group. The PLIF group showed a significant decrease in the disc height and segmental lordotic angle when compared with the OLIF group in the postoperative 1-year period.

Conclusion

Both OLIF and PLIF showed similar clinical outcomes in the single-level lumbar fusion. However, OLIF grafts showed an advantage over PLIF with respect to the radiographic outcomes and complication rates. Additionally, partial laminectomy did not significantly affect the radiological results.

Incidence of major and minor vascular injuries during lateral access lumbar interbody fusion procedures: a retrospective comparative study and systematic literature review

During lateral lumbar fusion, the trajectory of implant insertion approaches the great vessels anteriorly and the segmental arteries posteriorly, which carries the risk of vascular complications. We aimed to analyze vascular injuries for potential differences between oblique lateral interbody fusion (OLIF) and lateral lumbar interbody fusion (LLIF) procedures at our institution. This was coupled with a systematic literature review of vascular complications associated with lateral lumbar fusions. A retrospective chart review was completed to identify consecutive patients who underwent lateral access fusions. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used for the systematic review with the search terms "vascular injury" and "lateral lumbar surgery." Of 260 procedures performed at our institution, 211 (81.2%) patients underwent an LLIF and 49 (18.8%) underwent an OLIF. There were no major vascular complications in either group in this comparative study, but there were four (1.5%) minor vascular injuries (2 LLIF, 0.95%; 2 OLIF, 4.1%). Patients who experienced vascular injury experienced a greater amount of blood loss than those who did not (227.5 ± 147.28 vs. 59.32 ± 68.30 ml) (p = 0.11). In our systematic review of 63 articles, major vascular injury occurred in 0-15.4% and minor vascular injury occurred in 0-6% of lateral lumbar fusions. The systematic review and comparative study demonstrate an increased rate of vascular injury in OLIF when compared to LLIF. However, vascular injuries in either procedure are rare, and this study aids previous literature to support the safety of both approaches.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Lateral lumbar interbody fusion using a cellular allogeneic bone matrix in the treatment of symptomatic degenerative lumbar disc disease and lumbar spinal instability

Background

Cellular allogeneic bone grafts are used as a biologic adjuvant in lumbar spinal fusions. The clinical use of a minimally invasive extreme lateral approach to the lumbar spine has been widely adopted; however, there are few clinical studies that have documented the clinical and radiographic outcomes associated with the use of cellular allografts as an adjunct to fusion in this advanced surgical approach.

Methods

A consecutive series of 67 patients (34 males and 33 females) with a mean age of 66.8 years (26-85 years) who underwent single- or multilevel lateral lumbar interbody fusion (LLIF) with supplemental posterior segmental spinal fixation using a cellular allogeneic bone matrix as the only bone graft material was retrospectively reviewed by a single surgeon. Patients' preoperative and 3- and 12-month postoperative data were studied. All patients were followed for a minimum of 12 months. Standardized clinical outcome measures-36-Item Short Form Surgery (SF-36), Oswestry Disability Index (ODI), and visual analog scale (VAS) back and leg pain scores-were used to evaluate the clinical outcomes. An average of 2.25 levels was treated per patient (151 total levels). Fusion status was assessed by dynamic radiographs and computed tomography (CT) scans. The statistical method used to identify the significance of the observed changes in clinical outcomes was the paired 2-sided t-tests. Significance was ascribed to P values <0.05.

Results

Fusion was achieved at 142 levels (142/151; 94%). Eight levels (8/151; 5.3%) showed partial fusions and one patient (single level) had no fusion. In the group of patients with fusions, the mean back and leg pain scores showed improvement from preoperative scores at both 3 and 12 months (P<0.001). Functional outcomes showed similar clinical success in both in SF-36 and ODI scores.

Conclusions

The use of a cellular allogeneic bone matrix provided osteoconductive and osteoinductive components for successful spine fusions and was associated with statistically significant improvement in SF-36, VAS, and ODI scores.

Comparison of Simultaneous Single-Position Oblique Lumbar Interbody Fusion and Percutaneous Pedicle Screw Fixation with Posterior Lumbar Interbody Fusion Using O-arm Navigated Technique for Lumbar Degenerative Diseases

Minimally invasive posterior or transforaminal lumbar interbody fusion (MI-PLIF/TLIF) are widely accepted procedures for lumbar instability due to degenerative or traumatic diseases. Oblique lateral interbody fusion (OLIF) is currently receiving considerable attention because of the reductions in damage to the back muscles and neural tissue. The aim of this study was to compare clinical and radiographic outcomes of simultaneous single-position OLIF and percutaneous pedicle screw (PPS) fixation with MI-PLIF/TLIF. This retrospective comparative study included 98 patients, comprising 63 patients with single-position OLIF (Group SO) and 35 patients with MI-PLIF/TLIF (Group P/T). Cases with more than 1 year of follow-up were included in this study. Mean follow-up was 32.9 ± 7.0 months for Group SO and 33.7 ± 7.5 months for Group P/T. Clinical and radiological evaluations were performed. Comparing Group SO to Group P/T, surgical time and blood loss were 118 versus 172 min (p < 0.01) and 139 versus 374 mL (p < 0.01), respectively. Cage height, change in disk height, and postoperative foraminal height were significantly higher in Group SO than in Group P/T. The fusion rate was 96.8% in Group SO, similar to the 94.2% in Group P/T (p = 0.985). The complication rate was 6.3% in Group SO and 14.1% in Group P/T (p = 0.191). Simultaneous single position O-arm-navigated OLIF reduces the surgical time, blood loss, and time to ambulation after surgery. Good indirect decompression can be achieved with this method.

Prevalence and location of endplate fracture and subsidence after oblique lumbar interbody fusion for adult spinal deformity

BACKGROUND

Recently, Oblique lumbar interbody fusion (OLIF) is commonly indicated to correct the sagittal and coronal alignment in adult spinal deformity (ASD). Endplate fracture during surgery is a major complication of OLIF, but the detailed location of fracture in vertebral endplate in ASD has not yet been determined. We sought to determine the incidence and location of endplate fracture and subsidence of the OLIF cage in ASD surgery, and its association with fusion status and alignment.

METHODS

We analyzed 75 levels in 27 patients were analyzed using multiplanar CT to detect the endplate fracture immediately after surgery and subsidence at 1 year postoperatively. The prevalence was compared between anterior and posterior, approach and non-approach sides, and concave and convex side. Their association with fusion status, local and global alignment, and complication was also investigated.

RESULTS

Endplate fracture was observed in 64 levels (85.3%) in all 27 patients, and the incidence was significantly higher in the posterior area compared with the anterior area (85.3 vs. 68.0%, p=0.02) of affected vertebra in the sagittal plane. In the coronal plane, there was no significant difference in incidence between left (approach) and right (non-approach) sides (77.3 and 81.3%, respectively), or concave and convex sides (69.4 and 79.6%) of wedged vertebra. By contrast, cage subsidence at 1 year postoperatively was noted in 14/75 levels (18.7%), but was not associated with endplate fracture. Fusion status, local and global alignment, and complications were not associated with endplate fracture or subsidence.

CONCLUSION

Endplate fracture during OLIF procedure in ASD cases is barely avoidable, possibly induced by the corrective maneuver with ideal rod counter and cantilever force, but is less associated with subsequent cage subsidence, fusion status, and sustainment of corrected alignment in long fusion surgery performed even for elderly patients.

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 .

Effectiveness and Safety of Adding Bevacizumab to Platinum-Based Chemotherapy as First-Line Treatment for Advanced Non-Small-Cell Lung Cancer: A Meta-Analysis

Background and Objective: Previous studies have evaluated the efficacy (OS, overall survival; PFS, progression-free survival; ORR, objective response rate) and adverse events of bevacizumab combined with platinum-based chemotherapy in first-line treatment of advanced non-small-cell lung cancer (NSCLC) compared with chemotherapy alone. However, the results were inconsistent.

Methods: We conducted a comprehensive search of PubMed, EMBASE, and Cochrane Library for potentially eligible articles. The outcomes were evaluated in terms of risk ratio (RR) or hazard ratio (HR) and the associated 95% confidence intervals (CIs). Meta-analysis was performed using the Stata 12.0 software, and subgroup analyses were performed based on the treatment and bevacizumab dose.

Results: Six randomized controlled trials with 2,465 patients were included in this meta-analysis. The results demonstrated that bevacizumab significantly increased OS (HR = 0.87, 95% CI 0.79–0.96), extended PFS (HR = 0.65, 95% CI 0.54–0.77), and increased ORR (ES = 0.40, 95% CI 0.31–0.48) when added to first-line platinum-based chemotherapy in patients with advanced NSCLC. Subgroup analyses showed that only the higher dose (15 mg/kg) of bevacizumab plus carboplatin–paclitaxel significantly extended the OS and PFS, but both 7.5 mg/kg and 15 mg/kg of bevacizumab improved ORR. However, both 7.5 mg/kg and 15 mg/kg of bevacizumab could only increase PFS and ORR, but not extend OS, when added to cisplatin–gemcitabine. Bevacizumab significantly increased the risk of grade ≥3 events of febrile neutropenia, haemorrhagic events, hypertension, leukopenia, neutropenia, and proteinuria.

Conclusion: Bevacizumab significantly increases OS, PFS, and ORR when added to first-line platinum-based chemotherapy in patients with advanced NSCLC, with no new safety signals found. Moreover, bevacizumab (15 mg/kg) plus carboplatin–paclitaxel is a better alternative in increasing OS to carboplatin–paclitaxel and bevacizumab (7.5 mg/kg and 15 mg/kg) plus cisplatin–gemcitabine.

Learning Curve and Complications Experience of Oblique Lateral Interbody Fusion : A Single-Center 143 Consecutive Cases

OBJECTIVE

Oblique lateral interbody fusion (OLIF) is becoming the preferred treatment for degenerative lumbar diseases. As beginners, we performed 143 surgeries over 19 months. In these consecutive cases, we analyzed the learning curve and reviewed the complications in our experience.

METHODS

This was a retrospective study; however, complications that were well known in the previous literature were strictly recorded prospectively. We followed up the changes in estimated blood loss (EBL), operation time, and transient psoas paresis according to case accumulation to analyze the learning curve.

RESULTS

Complication-free patients accounted for 43.6% (12.9%, early stage 70 patients and 74.3%, late stage 70 patients). The most common complication was transient psoas paresis (n=52). Most of these complications occurred in the early stages of learning. C-reactive protein normalization was delayed in seven patients (4.89%). The operation time showed a decreasing trend with the cases; however, EBL did not show any significant change. Notable operation-induced complications were cage malposition, vertebral body fracture, injury to the ureter, and injury to the lumbar vein.

CONCLUSION

According to the learning curve, the operation time and psoas paresis decreased. It is important to select an appropriately sized cage along with clear dissection of the anterior border of the psoas muscle to prevent OLIF-specific complications.

Vitamin D receptor gene polymorphisms and osteoarthritis: a meta-analysis

OBJECTIVE

To investigate the association of vitamin D receptor (VDR) gene polymorphisms with OA susceptibility.

METHODS

Meta-analyses were performed using allelic contrast, contrast of homozygotes, and recessive and dominant models to clarify the association between OA and VDR ApaI, BsmI, TaqI and FokI polymorphisms. Odds ratio (OR) and the corresponding 95% CI were obtained, and subgroup analyses were performed based on the ethnicity and OA sites.

RESULTS

A total of 18 studies with 2983 OA patients and 4177 controls were included in this meta-analysis. There were statistically significant associations in the spine between OA susceptibility and the VDR BsmI (B vs b: OR = 1.25, 95% CI: 1.03, 1.53, P = 0.026; BB vs bb: OR = 1.56, 95% CI: 1.02, 2.37, P = 0.038) and TaqI (T vs t: OR = 0.73, 95% CI: 0.54, 0.99, P = 0.044; TT vs Tt + tt: OR = 0.63, 95% CI: 0.42, 0.95, P = 0.028) polymorphisms, but not for the other polymorphisms. A statistically significant association was found between the VDR FokI polymorphism and OA susceptibility in the knee in the recessive model contrast (FF vs Ff + ff: OR = 0.63, 95% CI: 0.42, 0.95, P = 0.028), but this result was only pooled from one study. However, no significant associations were found between the VDR ApaI polymorphism and OA. Besides, ethnic stratification also indicated that there was no significant association between VDR gene polymorphism and OA in Caucasians or Asians.

CONCLUSION

Our meta-analysis suggests that the VDR BsmI and TaqI polymorphisms are associated with OA susceptibility in the spine. However, the VDR ApaI polymorphism is not a significant genetic risk factor for OA.

A Study to Compare the Efficacy of a Biodegradable Dynamic Fixation System With Titanium Devices in Posterior Spinal Fusion Between Articular Processes in a Canine Model

The objective of this study was to apply a biodegradable dynamic fixation system (BDFS) for lumbar fusion between articular processes and compare the fusion results and biomechanical changes with those of conventional rigid fixation. Twenty-four mongrel dogs were randomly assigned to 2 groups and subjected to either posterior lumbar fusion surgery with a BDFS or titanium rods (TRs) at the L5-L6 segments. Six animals in each group were sacrificed at 8 or 16 weeks. Fusion conditions were evaluated by computed tomography (CT), manual palpation, biomechanical tests, and histological analysis. Biomechanical tests were performed at the L4-7 (for range of motion (ROM)) and L5-6 (for fusion stiffness) segments. Histological examination was performed on organs, surrounding tissues, and the fused area. The magnesium alloy components maintained their initial shape 8 weeks after the operation, but the meshing teeth were almost completely degraded at 16 weeks. The biomechanical analysis revealed an increased lateral bending ROM at 8 weeks and axial torsion ROM at 16 weeks. The L4-5 extension-flexion ROMs in the BDFS group were 2.29 ± 0.86 deg and 3.17 ± 1.08 deg at 16 weeks, respectively, compared with 3.22 ± 0.56 deg and 5.55 ± 1.84 deg in TR group. However, both groups showed similar fusion results. The BDFS design is suitable, and its degradation in vivo is safe. The BDFS can be applied for posterior lumbar fusion between articular processes to complete the fusion well. Additionally, the BDFS can reduce the decline in lateral motion and hypermotion of the cranial adjacent segment in flexion-extension motion.

Incidence of Major Vascular Injuries with Extreme Lateral Interbody Fusion (XLIF)

Background:

Extreme lateral interbody fusions (XLIF) and minimally invasive (MI) XLIF theoretically offer wide access to the lumbar disc space. The theoretical advantages of XLIF include; minimally disturbing surrounding structures (e.g. neural, vascular, soft-tissue), while offering stability. In addition to the well-known increased frequency of neurological deficits attributed to XLIF, here we explored how often major vascular injures occur with XLIF/MI XLIF procedures.

Methods:

In 13 XLIF/MI XLIF studies, we evaluated the frequency of major vascular injuries.

Results:

The studies citing the different frequencies of vascular injuries associated with XLIF/MI XLIF were broken down into three categories. Of the 5 small and larger case series, involving a total of 6,732 patients (e.g. range of 12 to 4,607 patients/study), the incidence of vascular injuries ranged from 0% (3 studies) up to 0.4%. Three case reports presented major vascular injuries attributed to XLIF/MI XLIF. Two involved the L4-L5 level. The three complications included: one fatal injury, one, a retroperitoneal hematoma with hemorrhagic shock, and one major vascular injury. For the 5 review articles, major vascular complications were just discussed in 2, one study cited 3 specific major vascular injuries (e.g. 1 fatal, 1 life threating, and 1 lumbar artery pseudoaneurysm requiring embolization), while 2 other studies stated the frequency of these injuries was 0.4% for XLIF, and 1.7 % for OLIF (Oblique Lumbar Interbody Fusion).

Conclusions:

According to 5 small and larger case series, 3 case reports, and 5 review articles, the incidence of major vascular injuries occurring during XLIF/MI XLIF ranges from 0 to 0.03% to 0.4%.

Anatomical Study of the Lumbar Segmental Arteries in Relation to the Oblique Lateral Interbody Fusion Approach

OBJECTIVE

To use computed tomography angiography to evaluate the regional anatomy of the lumbar segmental arteries (LAs) associated with the surgical field in oblique lateral interbody fusion (OLIF).

METHODS

Computed tomography angiography images from 50 patients were reviewed. In the sagittal plane, distances from the LA to the upper and inferior edges of the vertebral body were measured in the anterior quarter of the anterior and median lines of the intervertebral disc (IVD). LAs were classified as types I-IV based on the zone in which they passed through the vertebral body.

RESULTS

The LA branch angles were acute (<90°) at L1-L3 and blunt (>90°) at L4-L5. The average distances from the LA to the upper and inferior edges of the vertebral body in the anterior quarter position revealed that La1.2 > Lb1.2 and Lb3.4.5 > La3.4.5. For the IVD of L1-L2, Lb1 < La2; IVD of L2-L3, Lb2 < La3; IVD of L3-L4, Lb3 > La4; IVD of L4-L5, Lb4 > La5. In zone I, the most frequent LA type was type IV at L1 (n = 41; 85.4%) and L2 (n = 42; 84.0%), type III at L3 (n = 20; 40.0%), and type II at L4 (n = 36; 80.0%) and L5 (n = 5; 83.3%). In zone II, the most frequent LA type was type III at L1 (n = 38; 79.2%), L2 (n = 39; 78.0%), L3 (n = 43; 86.0%), and L4 (n = 28; 62.2%), whereas type II was the most frequent LA type at L5 (n = 5; 83.3%). In zone III, type III was the most frequent LA type at L1-L4. In zone IV, type IV was the most frequent LA type at L3 (n = 44; 88.0%), L4 (n = 42; 93.3%), and L5 (n = 6; 100%).

CONCLUSIONS

The risk of LA injury during OLIF is the least when the cage is placed in zones II and III. Care is required during OLIF in zone IV of L3-L5. The fixation pin should be fixed on the upper edge of the lower vertebral body at L1-L2 and L2-L3, and on the lower edge of the upper vertebral body at L3-L4 and L4-L5.