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

Radiological Outcomes and Approach-Related Complications in Oblique Lateral Interbody Fusion at the Upper Lumbar Level

Background/Objectives: Despite recent advances in minimally invasive extrapleural lateral approaches, oblique lateral interbody fusion (OLIF) at the upper lumbar level is often difficult and limited to optimal reconstruction. We aimed to compare the radiological outcomes and approach-related complications of OLIF between the upper (L1-2 or L2-3) and lower (L3-4 or L4-5) levels. Methods: This study is a retrospective review of OLIF in the upper (n = 63) and lower (n = 60) lumbar level groups. Radiological parameters included the anterior/posterior disc height, coronal/sagittal disc angle, cage position, cage subsidence, and fusion rate at a postoperative 1-year follow-up. Approach-related complications including pleural/peritoneal lacerations, neurovascular injury, and other organ injuries were examined. Results: The baseline radiological parameters were similar between the two groups (all p > 0.05). At 1-year postoperatively, the anterior disc height (ADH) was significantly greater in the lower-level group (p = 0.031), while no significant differences were observed in the posterior disc height, coronal/sagittal disc angle, cage anterior position, or cage subsidence rate (all p > 0.05). The fusion rates were 97.9% and 95.0% at the upper and lower lumbar levels, respectively (p = 0.146). During OLIF at the upper lumbar level, chest tube insertion due to pleural laceration was observed in 11 (17.5%) cases. One case (1.2%) of segmental artery injury and two cases (3.2%) of pseudo-hernia were attributed to iliohypogastric nerve injury. Conclusions: Although the extrapleural approach in OLIF at the upper lumbar level is often limited, the radiological outcomes were comparable to those of OLIF at the lower lumbar level.

Instrumented Facet Fusion in the Lumbosacral Spine: Long-Term Clinical and Radiographic Results

OBJECTIVE

Surgical treatments for degenerative lumbar spinal disorders involve decompression of neural structures and arthrodesis to address pain from unstable intervertebral segments. Lumbar instrumented facet fusion (IFF), a less invasive technique, has shown positive short-term outcomes, but reports on its long-term outcomes are scarce. This study aims to report its long-term biomechanical stability and clinical outcomes.

METHODS

This single-center retrospective observational case series included patients who underwent single- or two-level IFF for degenerative lumbar spinal disorders from January 1996 to January 2021. Patient demographics, Oswestry Disability Index and visual analog scale scores, and radiographic fusion were assessed using flexion-extension radiographs and CT scans. Instrument failures and fusion segment angles were measured.

RESULTS

A total of 494 patients underwent IFF during the studied period. Of those, 208 were followed up for more than 24 months (mean follow-up of 89.96 ± 55.59 months). The overall fusion rate was 92.05%. Revision surgery due to adjacent segmental disease was done in 11.06% of patients. Screw loosening was observed in 6 patients, of whom 2 underwent revision surgery. Significant improvements in Oswestry Disability Index and visual analog scale were observed.

CONCLUSIONS

IFF is a safe and less invasive alternative method of lumbar spinal arthrodesis with a comparable fusion rate and clinical outcome. This method shows a relatively low revision rate.

Novel Instruments for Full Endoscopic Trans-Kambin Triangle Lumbar Interbody Fusion With Reverse Oblique Lateral Cage Insertion: A Case Report and Technical Note

BACKGROUND

Lumbar interbody fusion with screw fixation is a standard treatment for lumbar degenerative diseases. While full-endoscopic lumbar interbody fusion is minimally invasive, it utilizes smaller cages compared with the oblique lateral interbody fusion (OLIF) technique, which offers superior biomechanical support. To merge full-endoscopic lumbar interbody fusion minimal invasiveness with OLIF's advantages, we developed a novel instrument, the Single Beak Adjustable Cage Glider, to facilitate OLIF cage insertion via the full-endoscopic trans-Kambin triangle approach. This note and case report introduce this alternative solution.

CASE PRESENTATION

In a case of L4 to L5 spondylolisthesis, we performed fluoroscopy-guided uniportal facet-preserving trans-Kambin endoscopic fusion surgery. We initially installed percutaneous pedicle screws and rods to correct the anterolisthesis, then established the endoscopic trans-Kambin approach. After releasing the disc-endplate junction, the nerve root was mobilized and protected by the beak of the cage glider. The disc space was cleared, and a 22 × 40 × 12 mm interbody device was inserted through the cage glider under fluoroscopic guidance. The integrity of the exiting nerve root was confirmed with an endoscope.

RESULTS

Postoperatively, the patient experienced significant improvements in both low back pain and bilateral lower limb numbness. Muscle strength in both lower limbs returned to baseline, and the patient was able to walk independently without assistive devices. Follow-up radiographs and computed tomography scans showed a well-reduced regional lordotic angle, and the axial computed tomography view confirmed adequate decompression of the spinal canal while preserving the facet joints.

CONCLUSIONS

The Single Beak Adjustable Cage Glider enables precise positioning of the OLIF cage through the Kambin triangle lumbar interbody fusion approach, avoiding nerve root injury and preserving facet joints. This technique reduces surgical trauma and maintains spine biomechanics, potentially improving patient outcomes.

CLINICAL RELEVANCE

This technique potentially reduces the cage subsidence rate.

LEVEL OF EVIDENCE: 5

Analysis of the therapeutic efficacy of OLIF combined with posterior percutaneous pedicle screw fixation in the treatment of patients with primary lumbar spondylodiscitis

Introduction

Primary lumbar spondylodiscitis is a serious condition with an increasing incidence rate.

Methods

From January 2021 to June 2023, we adopted a single-stage oblique lateral approach for the debridement of lumbar infection foci, intervertebral bone grafting fusion, tube irrigation drainage, combined with posterior percutaneous pedicle screw fixation for the treatment of primary lumbar spondylodiscitis.

Results

We found that this surgical technique significantly improved the patients' lower back pain symptoms. During postoperative follow-ups at 1, 3, 6, and 12 months, patients showed remarkable improvements in their JOA and VAS scores, as well as in ESR and CRP levels, compared to the preoperative period.

Discussion

We believe that the single-stage oblique lateral approach for debridement of lumbar infection foci, intervertebral bone grafting fusion, tube irrigation drainage, and combined posterior percutaneous pedicle screw fixation is an ideal treatment method for primary lumbar spondylodiscitis. This technique offers thorough debridement of the infection focus, sufficient bone grafting, safe operation, and reliable fixation.

The risk factors for low back pain following oblique lateral interbody fusion: focus on sarcopenia

BACKGROUND

Sarcopenia had been identified as a factor influencing the postoperative outcomes of lumbar surgery. The effect of sarcopenia on the surgical outcomes in patients who underwent oblique lateral interbody fusion (OLIF) had not yet been examined.

OBJECTIVE

The aim of our study was to investigate the association between sarcopenia and postoperative low back pain (LBP) in patients following OLIF and provide recommendations for surgical strategy.

METHODS

116 patients who underwent OLIF were retrospectively reviewed. Patients were classified into sarcopenia group (Group SP) and non-sarcopenia group (Group NSP). According to whether instruments was performed, Group SP was further divided into OLIF stand-alone group (Group SP-SA) and OLIF with instruments group (Group SP-IN). The patient characteristics, surgical data and questionnaire scores were collected. Oswestry Disability Index (ODI) score was used to evaluate lumbar function and pain intensity. Multivariable logistic regression analysis was used to identify the risk factors for postoperative LBP.

RESULTS

There were 38 patients in Group SP and 78 patients in Group NSP. The incident rare of osteoporosis in Group SP was higher than that in Group NSP (P = 0.012). In Group SP, last follow-up intervertebral height (IH) was lower (P = 0.045) and incident rate of cage subsidence was higher ((P = 0.044). No significant difference (P = 0.229) showed in preoperative ODI scores, however, last follow-up ODI scores in Group SP was significantly higher (P = 0.017) than that in Group NSP. Multivariable logistic regression analysis showed that sarcopenia (P = 0.004), osteoporosis (P = 0.012) and cage subsidence (P = 0.002) were identified as risk factors for postoperative LBP. In Group SP-IN, last follow-up ODI score (P = 0.024) and incident rate of cage subsidence (P = 0.027) were significantly lower Compared to Group SP-SA.

CONCLUSIONS

LBP was a common complication following OLIF with the incidence rate of 18.1%. Sarcopenia, osteoporosis and cage subsidence were risk factors for LBP following OLIF. Instruments effectively reduced the incidence and degree of postoperative LBP in patients with sarcopenia following OLIF. Consequently, we suggest incorporating supplementary instruments for patients with sarcopenia in surgical strategy.

Which subtypes of degenerative lumbar spondylolisthesis are suitable for oblique lumbar interbody fusion? A retrospective study in China based on the clinical and radiographic degenerative spondylolisthesis classification

STUDY DESIGN

Retrospective study.

PURPOSE

To evaluate the radiological characteristics of degenerative lumbar spondylolisthesis (DS) and analyze the suitability of oblique lumbar interbody fusion (OLIF) for different DS subtypes.

OVERVIEW OF LITERATURE

OLIF has gained distinction for its minimal invasiveness and quicker recovery. Despite its promising effectiveness in treating DS, variations in patient characteristics necessitate precise surgical technique selection. The clinical and radiographic degenerative spondylolisthesis (CARDS) classification aids in identifying suitable DS subtypes.

METHODS

From March 2020 to March 2023, 100 inpatients with DS were classified into groups A, B, C, and D based on the CARDS classification system. Preoperative radiological data were analyzed to measure the severity of central canal stenosis, facet joint arthropathy, intervertebral disc herniation, and spinal epidural lipomatosis, osteophyte formation, range of motion (ROM), and computed tomography value of the vertebral bodies. The radiological characteristics and clinical contraindications for OLIF were compared among the groups.

RESULTS

Of the 100 patients, 51% had clinical contraindications for OLIF, which included 85%, 25%, 62.5%, and 20% of patients in groups A, B, C, and D, respectively. Compared with group B, group A demonstrated greater severity of central canal stenosis, whereas group C showed a higher degree of facet joint arthropathy. More patients in groups A and C had severe central canal stenosis. Regarding the ROM results, group A had segmental stiffness, whereas group D presented relatively unstable slip segments.

CONCLUSIONS

Patients with different DS subtypes have varied radiological characteristics. Groups B and D are suitable candidates for OLIF. Most patients in group A are unsuitable for OLIF because of bony hyperplasia, severe spinal stenosis, and segmental stiffness.

A New Pilot Hole Preparation System for Percutaneous Pedicle Screw Placement: A Randomized Controlled Study

STUDY DESIGN

A randomized controlled study.

OBJECTIVE

To introduce a new pilot hole preparation system for percutaneous pedicle screw placement and investigate its efficiency and safety in comparison with the conventional method.

SUMMARY OF BACKGROUND DATA

Placing screws accurately, rapidly, and safely with less radiation exposure is critical for minimally invasive lumbar interbody fusion (LIF). Optimizing pilot hole preparation instruments has important clinical implications.

MATERIALS AND METHODS

A total of 60 patients (180 screws) were included in this study. All patients were randomized into two groups (new system vs. conventional method) and performed single-level minimally invasive percutaneous fixation, interbody fusion, and unilateral decompression. Basic information, time of pilot hole preparation, time of screw placement, and fluoroscopy time were recorded. Screw placement accuracy was graded based on the Gertzbein-Robbins scale, and the angle between the screw axis and the pedicle axis was collected in postoperative CT.

RESULTS

There was no statistical difference in basic information between the 2 groups. The mean time of single pilot hole preparation was 4.08±1.01 minutes in the new system group and 5.34±1.30 minutes in the conventional method group ( P <0.001). The time of single screw placement was significantly shorter in the new system group (0.82±0.20 vs. 1.72±0.33 min), and the fluoroscopy time was also less in the new system group (13.70±3.42 vs. 19.95±5.50 s) ( P <0.001). Screw placement accuracy assessment showed that there were 85 (94.45%) A-grade screws in the new system group while 76 (84.44%) A-grade screws in the conventional method group ( P =0.027).

CONCLUSIONS

The new pilot hole preparation system has shown significant reductions in the time of pilot hole preparation, time of screw placement, and radiation exposure, and has good clinical application value.

Intraoperative Facet Joint Block Reduces Pain After Oblique Lumbar Interbody Fusion: A Double-Blinded, Randomized, Placebo-Controlled Clinical Trial

BACKGROUND

Oblique lumbar interbody fusion (OLIF) results in less tissue damage than in other surgeries, but immediate postoperative pain occurs. Notably, facet joint widening occurs in the vertebral body after OLIF. We hypothesized that the application of a facet joint block to the area of widening would relieve facet joint pain. The purpose of this study was to evaluate the analgesic effects of such injections on postoperative pain.

METHODS

This double-blinded, placebo-controlled study randomized patients into 2 groups. Patients assigned to the active group received an intra-articular injection of a compound mixture of bupivacaine and triamcinolone, whereas patients in the placebo group received an equivalent volume of normal saline solution injection. Back and dominant leg pain were evaluated with use of a visual analog scale (VAS) at 12, 24, 48, and 72 hours postoperatively. Clinical outcomes were evaluated preoperatively and at 6 months postoperatively with use of the Oswestry Disability Index (ODI) and VAS for back and dominant leg pain.

RESULTS

Of the 61 patients who were included, 31 were randomized to the placebo group and 30 were randomized to the active group. Postoperative fentanyl consumption from patient-controlled analgesia was higher in the placebo group than in the active group at up to 36 hours postoperatively (p < 0.001) and decreased gradually in both groups. VAS back pain scores were significantly higher in the placebo group than in the active group at up to 48 hours postoperatively. On average, patients in the active group had a higher satisfaction score (p = 0.038) and were discharged 1.3 days earlier than those in the placebo group.

CONCLUSIONS

The use of an intraoperative facet joint block decreased pain perception during OLIF, thereby reducing opioid consumption and the severity of postoperative pain. This effect was also associated with a reduction in the length of the stay.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Lateral Fusion is a Unique Feature in Oblique Lumbar Interbody Fusion Surgery: A Retrospective Cohort Study

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Limited clinical literature addresses potential differences in fusion features between Oblique lumbar interbody fusion (OLIF) and transforaminal lumbar interbody fusion (TLIF). We observed that in OLIF, there are many cases with the appearance of extra-vertebral bone bridges (EVB), a phenomenon distinct from traditional TLIF fusion. This study aims to compare fusion rates, cage subsidence, and fusion features among OLIF stand-alone (OLIF-SA), OLIF with posterior pedicle screw fixation (OLIF-PS), and TLIF.

METHODS

We retrospectively analyzed 198 patients (311 levels) undergoing OLIF-SA, OLIF-PS, or TLIF from July 2017 to June 2021. We assessed patient-reported outcomes, cage subsidence, fusion rate, and fusion features on CT scans.

RESULTS

The study included 64 OLIF-SA patients (102 levels), 60 OLIF-PS patients (99 levels), and 74 TLIF patients (110 levels). Cage settling rates were 33.3% (OLIF-SA), 17.2% (OLIF-PS), and 32.8% (TLIF), with significant differences between OLIF-PS and TLIF (P < 0.05). Cage subsidence rates showed no significant difference: 11.8% (OLIF-SA), 9.1% (OLIF-PS), and 12.7% (TLIF) (P > 0.05). Fusion rates were 100% (OLIF-SA), 97.0% (OLIF-PS), and 96.4% (TLIF) (P = 0.167). Lateral fusion rates significantly differed: 49.0% (OLIF-SA), 30.3% (OLIF-PS), and 10.9% (TLIF) (P < 0.001). Preoperative osteophytes strongly promote lateral fusion (P < 0.001). VAS and ODI scores improved significantly post-surgery (P < 0.01).

CONCLUSIONS

OLIF-SA, OLIF-PS, and TLIF surgeries show satisfactory results with comparable fusion rates. Notably, distinctive differences exist in fusion features between OLIF and TLIF surgeries, with lateral fusion more prevalent in OLIF, particularly in OLIF-SA surgeries.

Postoperative urinary retention after oblique lumbar interbody fusion under the systematic management protocol

Oblique lumbar interbody fusion (OLIF) is a minimally invasive lateral lumbar fusion technique and patients are discharged 1-2 days after surgery. Because OLIF utilizes a retroperitoneal approach close to the superior hypogastric plexus, postoperative urinary retention (POUR) may not be an uncommon problem. The purpose of this study was to present the incidence and outcomes of POUR with a systematic care protocol. The records of 102 consecutive patients (M:F = 34:68; mean age, 68.0 ± 8.4 years) were retrospectively reviewed. After OLIF, the indwelling urinary catheter was immediately removed, and every patient was encouraged to void within 6 h. The POUR care protocol, following a clinical pathway, was based on residual urine (RU), which was monitored with an ultrasound bladder scan after each voiding or every 6 h for 48 h. The incidence rate of POUR was 44% (45/102) at 24 h, 17% (17/102) at 48 h, and 2% (2/102) at 1 month. Preoperative urological symptoms (odds ratio [OR] 3.2) and violation of the protocol (OR 28.3) were risk factors at 24 h. At 48 h, violation of the protocol was the only risk factor (OR 9.6). Identifying risk factors and a preemptive care protocol may reduce permanent POUR.

Cage Obliquity in Oblique Lumbar Interbody Fusion-How Common Is It and What Are the Effects on Fusion Rates, Subsidence, and Sagittal Alignment? A Computed Tomography-Based Analysis

BACKGROUND

Oblique lumbar interbody fusion (OLIF) through a prepsoas approach was identified as an alternative to alleviate complications associated with direct lateral interbody fusion. Cage placement is known to influence cage subsidence and fusion rates due to suboptimal biomechanics. There are limited studies exploring cage obliquity as a potential factor influencing fusion outcomes. Hence, our objective was to assess the effects of cage obliquity and position on fusion rates, subsidence, and sagittal alignment in patients who underwent OLIF.

METHODS

Patients who underwent OLIF for levels L1 to L5 in our center, performed by a single surgeon and with a minimum of 12 months of follow-up, were included in the study. Cage obliquity and sagittal placement were measured, and their correlation with fusion, subsidence, and sagittal alignment correction was assessed. Fusion and subsidence were evaluated using the Bridwell Criteria and Marchi Criteria, respectively.

RESULTS

Among the included patients (age, 67.5 ± 7.93 years; 16 men and 37 women), 97 fusion levels were studied. The mean cage obliquity was 4.2° ± 2.8°. Ninety-six levels (99.0%) were considered to have achieved fusion with a Bridwell score of 1 or 2. Eighty-one (83.5%), 14 (14.4%), and 2 (2.06%) operated levels had a Marchi score of 0, 1, and 2, respectively. A Marchi grade of 1 or higher was considered indicative of significant subsidence. There was good improvement in both the segmental lordosis angle (4.2° ± 5.7°; P < 0.0001) and disc height (4.5 ± 3.8 mm; P < 0.0001). Cage placement did not have any statistical correlation with fusion rates, subsidence, or sagittal alignment.

CONCLUSIONS

Our results indicate that OLIF facilitates appropriate cage placement with only a minor degree of cage obliquity, typically less than 20°. This minor obliquity does not lead to lower fusion rates, increased subsidence, or sagittal malalignment. Despite subsidence being common, the majority of these cases resulted in complete fusion.

LEVEL OF EVIDENCE: 3

Unique characteristics of bone union at the infected vertebrae after minimally invasive posterior fixation without bone grafting in thoracolumbar pyogenic spondylitis: a retrospective multicenter cohort study

BACKGROUND

The current study aimed to evaluate the bone union rate between infected vertebrae after minimally invasive posterior fixation without bone grafting in thoracolumbar pyogenic spondylitis.

METHODS

This retrospective multicenter cohort study evaluated 75 patients of posterior fixation for thoracolumbar pyogenic spondylitis that have been recorded at six relevant institutions from January 2016 to December 2022. Data on age, sex, location of infected vertebrae, number of infected disks, comorbidity, Pola classification, number of vertebrae fixed according to surgery, implant failure requiring revision surgery, and distance according to the type of infected vertebrae after surgery were evaluated. Further, their association with postoperative bone union was investigated > 12 months postoperatively.

RESULTS

Finally, 40 patients were included in the study. In total, 32 (80%) patients achieved bone union at the infected vertebrae after minimally invasive posterior fixation without bone grafting. The mean duration from surgery to union was 10.7 months. Twenty-six (65%) patients initially achieved bone union at the lateral and/or anterior bridging callus. Patients with multiple-level infected disks (33%, 2/6 patients) had a lower bone union rate than those with a single-level infected disk (88%, 30/34 patients) (p = 0.0095).

CONCLUSIONS

In 80% of patients, bone union at the infected vertebrae was achieved after minimally invasive posterior fixation without bone grafting in thoracolumbar pyogenic spondylitis. A total of 65% of the patients achieved initial bone union at the lateral and/or anterior bridging callus. Moreover, patients with multiple-level infected disks had a low bone union rate. Hence, the treatment strategy should be cautiously considered.

TRIAL REGISTRATION

This study was registered retrospectively and all procedures used in this study including the review of patient records were approved by the institutional review board.

Anterior Column Realignment Using an Anterior-To-Psoas Approach: A Radiographic-Anatomic Feasibility Study at L1-L5

STUDY DESIGN

Cross-sectional radioanatomic study.

OBJECTIVE

To determine the feasibility of performing an anterior column realignment (ACR) using an anterior-to-psoas (ATP) approach at L1-L5.

METHODS

Axial magnetic resonance images (MRI) of the L1-L5 disc levels obtained at a single institution were obtained and analyzed. The feasibility of performing an ACR was assessed using a combination of the size of the left oblique corridor (OC), the psoas morphology using the modified Moro classification, and the anterior disc edge to great vessel distance.

RESULTS

Three hundred MRI studies obtained from 300 patients were included. All patients had a measurable left OC at the L1-L4 levels. Twenty patients (6.7%) had no measurable OC at the L4-L5 level. According to the modified Moro's classification, a high-rising psoas was seen in 4 patients (1.3%) at the L3-L4 level and 57 patients (19.0%) at the L4-L5 level. An ALL release was considered high risk due to no measurable space between the anterior disc edge and the great vessels in 54 patients (18.0%) at the L1-L2 level, 39 patients (13.0%) at the L2-L3 level, 119 patients (39.7%) at the L3-L4 level, and 226 patients (75.3%) at the L4-L5 level.

CONCLUSION

ACR using an ATP approach is the most radioanatomically feasible at L2-L3. The L4-L5 level has the highest risk with regards to both the ATP approach and the ALL release for an ACR due to high rates of unmeasurable left OC and space between the anterior disc edge and the great vessels.

A Comprehensive Analysis of Potential Complications after Oblique Lumbar Interbody Fusion : A Review of Postoperative Magnetic Resonance Scans in Over 400 Cases

OBJECTIVE

This study focuses on identifying potential complications following oblique lumbar interbody fusion (OLIF) through routine magnetic resonance (MR) scans.

METHODS

From 650 patients who underwent OLIF from April 2018 to April 2022, this study included those with MR scans taken 1-week post-operatively, and only for indirect decompression patients. The analysis evaluated postoperative MR images for hematoma, cage insertion angles, and indirect decompression efficiency. Patient demographics, post-operatively symptoms, and complications were also evaluated.

RESULTS

Out of 401 patients enrolled, most underwent 1- or 2-level OLIF. Common findings included approach site hematoma (65.3%) and contralateral psoas hematoma (19%). The caudal level OLIF was related with less orthogonality and deep insertion of cage. Incomplete indirect decompression occurred in 4.66% of cases but did not require additional surgery. Rare but symptomatic complications included remnant disc rupture (four cases, 1%) and synovial cyst rupture (four cases, 1%).

CONCLUSION

This study has identified potential complications associated with OLIF, including approach site hematoma, contralateral psoas hematoma, cage malposition risk at caudal levels, and radiologically insufficient indirect decompression. Additionally, it highlights rare, yet symptomatic complications such as remnant disc rupture and synovial cyst rupture. These findings contribute insights into the relatively under-explored area of OLIF complications.

Oblique Lumbar Interbody Fusion Combined with Posterior Percutaneous Pedicle Screw Internal Fixation: Does Variability in Cage Position Influence Clinical Outcomes?

OBJECTIVE

The study investigates how cage positions in oblique lumbar interbody fusion (OLIF) combined with posterior percutaneous pedicle screw internal fixation (PPSF) affect lumbar canal and foraminal decompression and postoperative outcomes, providing guidance for optimal placement and efficacy assessment.

METHODS

This investigation assesses radiologic outcomes and follow-up data in relation to cage position variability among 80 patients who underwent L4/5 single-segment OLIF + PPSF from 2018 to 2022.

RESULTS

In the study involving 80 participants, the combination of OLIF and PPSF significantly improved lower back and leg symptoms in patients, leading to positive clinical outcomes during follow-up. The intervertebral disk height increased from an average of 8.10 ± 2.79 mm before surgery to 11.75 ± 2.14 mm after surgery (P < 0.001). Additionally, this surgical technique notably increased the FH (P < 0.001) and expanded the DCSA from 68.81 ± 53.89 mmˆ2 before surgery to 102.91 ± 60.46 mmˆ2 after surgery (P < 0.001). Linear results suggest that changes in the position of the cage do not affect spinal imaging parameters. There is no significant difference in the correction of spinal parameters or prognosis whether the cage is back, middle, ahead.

CONCLUSIONS

In the OLIF + PPSF procedure, strict requirements for cage position are not necessary to achieve predetermined spinal biomechanical parameters. The practice of repeated fluoroscopy to adjust cage position postimplantation does not provide added clinical benefits to the patient.

Effects of the Severity of Stenosis on Clinical Outcomes of Indirect Decompression Using Oblique Lumbar Interbody Fusion

Background: No consensus has been reached regarding the efficacy of indirect decompression through oblique lumbar interbody fusion (OLIF) in severe lumbar spinal stenosis (LSS). This study investigated the impact of preoperative magnetic resonance imaging (MRI)-based grading of central and foraminal stenosis on OLIF outcomes in LSS patients and identified risk factors for postoperative clinical dissatisfaction. Methods: We retrospectively reviewed LSS patients who underwent OLIF with a minimum 1-year follow-up. Clinical scores obtained preoperatively and at 3, 6, 12, and 24 months postoperatively were analyzed using the substantial clinical benefit (SCB) framework. The severity of central and foraminal stenosis in the initial MRI was assessed through qualitative grading systems. Results: Among the 145 patients, with a mean follow-up of 33.7 months, those with severe central stenosis showed a significantly higher proportion of patients achieving SCB in the visual analog scale for leg pain (94.5% versus 83.1%; p = 0.044) at one year postoperatively than those without. However, those with severe foraminal stenosis showed significantly higher Oswestry Disability Index (ODI) scores (p = 0.024), and lower walking ability scores in the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) (p = 0.004) at one year postoperatively than those without. The presence of a foraminal osteophyte of the superior articular process (SAP) was a significant risk factor responsible for not achieving SCB in ODI and walking ability in JOABPEQ at one year postoperatively (odds ratio: 0.20 and 0.22, respectively). Conclusions: After OLIF, patients with severe central stenosis showed clinical outcomes comparable to those without. The improvement in ODI and walking ability in JOABPEQ was limited in patients with severe foraminal stenosis. Surgeons should consider direct decompression in cases with the presence of foraminal osteophytes of SAP.

Oblique lateral interbody fusion at L5-S1: feasibility, surgical approach window, incision line, and influencing factors

PURPOSE

The primary aim of this study was to describe the feasibility, surgical approach window (SAW), and incision line (IL) for oblique lateral interbody fusion at L5-S1 (OLIF51) using computed tomography (CT). A secondary aim was to identify associations among approach characteristics and demographic and anthropometric factors.

METHODS

We performed a radiographic study of 50 male and 50 female subjects who received abdominal CT imaging. SAW was measured as the distance from the midline to the medial border of the iliac vessel. IL was measured at the skin surface corresponding to the distance between the center of the disc space and SAW lateral margin. OLIF51 feasibility was defined as the existence of at least a 1-cm SAW without retraction of soft tissues.

RESULTS

For the left side, the OLIF51 SAW and IL were 12.1 ± 4.6 and 175.1 ± 55.3 mm. For the right side, these measures were 10.0 ± 4.3 and 185.0 ± 52.5 mm. Correlations of r = 0.648 (p < 0.001) and r = 0.656 (p < 0.001) were observed between weight and IL on the left and right sides, respectively. OLIF51 was not feasible 23% of the time.

CONCLUSION

To our knowledge, this is the largest CT study to determine the feasibility of performing an OLIF51. Without the use of retraction, OLIF51 is not feasible 23% of the time. Left-sided OLIF51 allows for a larger surgical approach window and smaller incision compared to the right side. Larger incisions are required for adequate surgical exposure in patients with higher weight.

The effect of polymethylmethacrylate augmentation on the primary stability of stand-alone implant construct versus posterior stabilization in oblique lumbar interbody fusion with osteoporotic bone quality- a finite element study

BACKGROUND CONTEXT

Oblique lumbar interbody fusion (OLIF) can provide an ideal minimally invasive solution for achieving spinal fusion in an older, more frail population where decreased bone quality can be a limiting factor. Stabilization can be achieved with bilateral pedicle screws (BPS), which require additional incisions and longer operative time. Alternatively, a novel self-anchoring stand-alone lateral plate system (SSA) can be used, where no additional incisions are required. Based on the relevant literature, BPS constructs provide greater primary biomechanical stability compared to lateral plate constructs, including SSA. This difference is further increased by osteoporosis. Screw augmentation in spinal fusion surgeries is commonly used; however, in the case of OLIF, it is a fairly new concept, lacking a consensus-based guideline.

PURPOSE

This comparative finite element (FE) study aimed to investigate the effect of PMMA screw augmentation on the primary stability of a stand-alone implant construct versus posterior stabilization in OLIF with osteoporotic bone quality.

STUDY DESIGN

The biomechanical effect of screw augmentation was studied inside an in-silico environment using computer-aided FE analysis.

METHODS

A previously validated and published L2-L4 FE model with normal and osteoporotic bone material properties was used. Geometries based on the OLIF implants (BPS, SSA) were created and placed inside the L3-L4 motion segment with increasing volumes (1-6 cm3) of PMMA augmentation. A follower load of 400 N and 10 Nm bending moment (in the three anatomical planes) were applied to the surgical FE models with different bone material properties. The operated L3-L4 segmental range of motion (ROM), the inserted cage's maximal caudal displacements, and L4 cranial bony endplate principal stress values were measured.

RESULTS

The nonaugmented values for the BPS construct were generally lower compared to SSA, and the difference was increased by osteoporosis. In osteoporotic bone, PMMA augmentation gradually decreased the investigated parameters and the difference between the two constructs as well. Between 3 cm3 and 4 cm3 of injected PMMA volume per screw, the difference between augmented SSA and standard BPS became comparable.

CONCLUSIONS

Based on this study, augmentation can enhance the primary stability of the constructs and decrease the difference between them. Considering leakage as a possible complication, between 3 cm3 and 4 cm3 of injected PMMA per screw can be an adequate amount for SSA augmentation. However, further in silico, and possibly in vitro and clinical testing is required to thoroughly understand the investigated biomechanical aspects.

CLINICAL SIGNIFICANCE

This study sheds light on the possible biomechanical advantage offered by augmented OLIF implants and provides a theoretical augmentation amount for the SSA construct. Based on the findings, the concept of an SSA device with PMMA augmentation capability is desirable.

Innovative Developments in Lumbar Interbody Cage Materials and Design: A Comprehensive Narrative Review

This review comprehensively examines the evolution and current state of interbody cage technology for lumbar interbody fusion (LIF). This review highlights the biomechanical and clinical implications of the transition from traditional static cage designs to advanced expandable variants for spinal surgery. The review begins by exploring the early developments in cage materials, highlighting the roles of titanium and polyetheretherketone in the advancement of LIF techniques. This review also discusses the strengths and limitations of these materials, leading to innovations in surface modifications and the introduction of novel materials, such as tantalum, as alternative materials. Advancements in three-dimensional printing and surface modification technologies form a significant part of this review, emphasizing the role of these technologies in enhancing the biomechanical compatibility and osseointegration of interbody cages. In addition, this review explores the increase in biodegradable and composite materials such as polylactic acid and polycaprolactone, addressing their potential to mitigate long-term implant-related complications. A critical evaluation of static and expandable cages is presented, including their respective clinical and radiological outcomes. While static cages have been a mainstay of LIF, expandable cages are noted for their adaptability to the patient's anatomy, reducing complications such as cage subsidence. However, this review highlights the ongoing debate and the lack of conclusive evidence regarding the superiority of either cage type in terms of clinical outcomes. Finally, this review proposes future directions for cage technology, focusing on the integration of bioactive substances and multifunctional coatings and the development of patient-specific implants. These advancements aim to further enhance the efficacy, safety, and personalized approach of spinal fusion surgeries. Moreover, this review offers a nuanced understanding of the evolving landscape of cage technology in LIF and provides insights into current practices and future possibilities in spinal surgery.

Expandable Cages for Lumbar Interbody Fusion: A Narrative Review

Lumbar fusion surgery for treating degenerative spinal diseases has undergone significant advancements in recent years. In addition to posterior instrumentation, anterior interbody fusion techniques have been developed along with various cages for interbody fusion. Recently, expandable cages capable of altering height, lordotic angle, and footprint within the disc space have garnered significant attention. In this manuscript, we review the current status, clinical outcomes, and future prospects of expandable cages for lumbar interbody fusion based on the existing literature. Expandable cages are suitable for minimally invasive spinal surgeries. Small-sized cages can be inserted and subsequently expanded to a larger size within the disc space. While expandable cages generally demonstrate superior clinical outcomes compared to static cages, some studies have suggested comparable or even poorer outcomes with expandable cages than static cages. Careful interpretation through additional long-term follow-ups is required to assess the utility of expandable cages. If these shortcomings are addressed and the advantages are further developed, expandable cages could become suitable surgical instruments for minimally invasive spinal surgeries.

The Combined Effects of RhBMP-2 and Systemic RANKL Inhibitor in Patients With Bone Density Loss Undergoing Posterior Lumbar Interbody Fusion: A Retrospective Observational Analysis With Propensity Score Matching

OBJECTIVE

The risks of nonunion and subsidence are high in patients with bone density loss undergoing spinal fusion surgery. The internal application of recombinant human bone morphogenic protein 2 (rhBMP-2) in an interbody cage improves spinal fusion; however, related complications have been reported. Denosumab, a human monoclonal antibody targeting the receptor activator of nuclear factor kappa B ligand (RANKL), hinders osteoblast differentiation and function. Therefore, this study aimed to observe the combined effect of the local application of rhBMP-2 in a lumbar cage and systemic RANKL inhibition on postoperative spinal fusion in patients with bone density loss undergoing posterior lumbar interbody fusion (PLIF).

METHODS

This retrospective observational study included 251 consecutive patients with spinal stenosis who underwent PLIF at a single center between 2017 and 2021. Clinical outcomes were assessed, and radiographic evaluations included lumbar flexion, extension, range of motion, and subsidence. Statistical analyses were conducted to identify the combined effect of the treatment and the subsidence and spinal fusion status.

RESULTS

One hundred patients were included in the final analysis. Denosumab treatment significantly reduced the rate of osteolysis (p = 0.013). When denosumab was administered in combination with rhBMP-2, the fusion status remained similar; however, the incidences of postoperative osteolysis and postoperative oozing day decreased.

CONCLUSION

The combined use of rhBMP-2 and RANKL inhibition in patients with bone density loss can enhance bone formation after PLIF with fewer complications than rhBMP-2 alone.

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.

Fusion Assessment of Oblique Lumbar Interbody Fusion Using Demineralized Bone Matrix: A 2-Year Prospective Study

OBJECTIVE

Although several studies have reported successful fusion rates after oblique lumbar interbody fusion (OLIF) using allografts or dimerized bone matrix (DBM) instead of autografts, whether OLIF can achieve satisfactory solid fusion without the use of autografts remains unclear. This study investigated the real fusion rates after OLIF using allografts and DBM, which were evaluated using both dynamic radiographs and computed tomography scans.

METHODS

We enrolled 79 consecutive patients who underwent minimally invasive OLIF followed by percutaneous pedicle screw fixation. All patients were treated with OLIF between L2 and L5 and underwent radiographic and clinical follow-ups at 12, 18, and 24 months after surgery. Radiographic assessment of fusion was performed using the modified BrantigaSteffee-Fraser (mBSF) scale, which was categorized as follows: grades I (radiographic pseudoarthrosis), II (indeterminate fusion), and III (solid radiographic fusion). Other radiologic and clinical outcomes were evaluated using the following parameters: vertebral slippage distance, disc height, subsidence, Oswestry Disability Index (ODI), and visual analogue scale (VAS).

RESULTS

Clinical outcomes demonstrated significant improvements in the VAS scores for back pain, leg pain, and ODI after surgery. Subsidence was present in 34 cases (35.4%) at 12 months postoperatively, which increased to 47.9% and reached 50.0% at 1.5 years and 2 years after surgery, respectively. The solid fusion rate after OLIF was 32.3% at 1 year, increased to 58.3% at 1.5 years, and reached 72.9% at 2 years. Radiographic pseudoarthrosis was 24.0% at 1 year, which decreased to 6.3% at 1.5 years and 3.1% at 2 years.

CONCLUSION

OLIF is a safe and effective surgical procedure for the treatment of degenerative lumbar diseases. The mBSF scale, which simultaneously evaluates both dynamic angles and bone bridge formation, offers great reliability for the radiological assessment of fusion. Moreover, OLIF using allografts and DBM, which is performed on one or 2 levels at L2-5, can achieve satisfactory fusion rates within 2 years after surgery.

An Expanded Surgical Corridor of Oblique Lateral Interbody Fusion at L4-5: A Magnetic Resonance Imaging Study

OBJECTIVE

We introduced a new preoperative method, the "expanded surgical corridor," to evaluate the actual safety corridor, which may expand the possibility of performing oblique lateral interbody fusion (OLIF).

METHODS

Axial T2-weighted magnetic resonance images at the L4-5 disc level of 511 lumbar degenerative disease patients was evaluated. The distance between the medial edge of the left-sided psoas muscle and the major artery was measured as the conventional surgical corridor (CSc). The distance between the major vein and lumbar plexus was measured as the expanded surgical corridor (ESc).

RESULTS

The mean CSc and ESc were 13.9 ± 8.20 and 37.43 ± 10.1 mm, respectively. No surgical corridor was found in 7.05% of CSc and 1.76% of ESc, small corridor ( ≤ 1 cm) was found in 27.40% of CSc and 0.59% of ESc, moderate corridor (1-2 cm) was found in 42.07% of CSc and 1.96% of ESc, and large corridor ( > 2 cm) was found in 23.48% of CSc and 95.69% of ESc. A total of 33.83% (45 of 133) of whom were preoperatively categorized as having a limited surgical corridor by conventional measurement, underwent OLIF L4-5 successfully.

CONCLUSION

By using the ESc, only 2.35% were categorized as having a limited surgical corridor. The other 97.65% of the patients had an approachable corridor that could be successfully operated by experienced spine surgeons who employ meticulous surgical dissection and thorough understanding of the anatomical structures. The ESc may represent true accessibility to the disc space for OLIF, particularly at the L4-5 level.

Effect of Stand-Alone Oblique Lateral Interbody Fusion (OLIF) in Treating Lumbar Spine Lesions

BACKGROUND The aim of this study was to investigate the safety and early clinical results of stand-alone oblique lateral interbody fusion (OLIF) in the fusion of lumbar spine lesions and to explore the indications for surgery. MATERIAL AND METHODS A total of 92 cases of lumbar spine lesions treated with stand-alone OLIF in 2 medical centers from October 2014 to December 2018 were retrospectively analyzed. We included 30 males and 62 females, ages 32-83 years. RESULTS Our results showed that the operation time was 60.92±27.40 min (average 36.6 min) and the intraoperative blood loss was 68.22±141.6 ml (average 23.8 ml). The height of the intervertebral space was restored - before the operation (9.23±1.94 mm) and (12.68±2.01 mm) after the operation - and it was 10.18±2.14 mm at the last follow-up. There was a significant difference between the postoperative and preoperative values (t=9.27, P<0.0001), and there was also a significant difference between the final follow-up and postoperative comparison value (t=8.43, P<0.0001). CONCLUSIONS The use of stand-alone OLIF in treating fusion of lumbar spine lesions showed excellent clinical efficacy and achieved the expected clinical improvements.

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.

Surgical treatment of spondylolisthesis by oblique lumbar interbody fusion and transpedicular screw fixation: Comparison between conventional double position versus navigation-assisted single lateral position

BACKGROUND AND OBJECTIVES

Oblique lumbar interbody fusion (OLIF) procedures involve anterior insertion of interbody cage in lateral position. Following OLIF, insertion of pedicle screws and rod system is performed in a prone position (OLIF-con). The location of the cage is important for restoration of lumbar lordosis and indirect decompression. However, inserting the cage at the desired location is difficult without reduction of spondylolisthesis, and reduction after insertion of interbody cage may limit the amount of reduction. Recent introduction of spinal navigation enabled both surgical procedures in one lateral position (OLIF-one). Therefore, reduction of spondylolisthesis can be performed prior to insertion of interbody cage. The objective of this study was to compare the reduction of spondylolisthesis and the placement of cage between OLIF-one and OLIF-con.

METHODS

We retrospectively reviewed 72 consecutive patients with spondylolisthesis for this study; 30 patients underwent OLIF-one and 42 underwent OLIF-con. Spinal navigation system was used for OLIF-one. In OLIF-one, the interbody cage was inserted after reducing spondylolisthesis, whereas in OLIF-con, the cage was inserted before reduction. The following parameters were measured on X-rays: pre- and postoperative spondylolisthesis slippage, reduction degree, and the location of the cage in the disc space.

RESULTS

Both groups showed significant improvement in back and leg pains (p < .05). Transient motor or sensory changes occurred in three patients after OLIF-con and in two patients after OLIF-one. Pre- and postoperative slips were 26.3±7.7% and 6.6±6.2% in OLIF-one, and 23.1±7.0% and 7.4±5.8% in OLIF-con. The reduction of slippage was 74.4±6.3% after OLIF-one and 65.4±5.7% after OLIF-con, with a significant difference between the two groups (p = .04). The cage was located at 34.2±8.9% after OLIF-one and at 42.8±10.3% after OLIF-con, with a significant difference between the two groups (p = .004).

CONCLUSION

Switching the sequence of surgical procedures with OLIF-one facilitated both the reduction of spondylolisthesis and the placement of the cage at the desired location.

Comparison of Lumbosacral Fusion Grade in Patients after Transforaminal and Anterior Lumbar Interbody Fusion with Minimum 2-Year Follow-Up

OBJECTIVE

Generally, anterior lumbar interbody fusion (ALIF) was believed superior to transforaminal lumbar interbody fusion (TLIF) in induction of fusion. However, many studies have reported comparable results in lumbosacral fusion rate between the two approaches. This study aimed to evaluate the realistic lumbosacral arthrodesis rates following ALIF and TLIF in patients with degenerative spondylolisthesis as measured by CT and radiology.

METHODS

Ninety-six patients who underwent single-level L5-S1 fusion through ALIF (n = 48) or TLIF (n = 48) for degenerative spondylolisthesis at the Spine Center, University of California San Francisco, between October 2014 and December 2017 were retrospectively evaluated. Fusion was independently evaluated and categorized as solid fusion, indeterminate fusion, or pseudarthroses by two radiologists using the modified Brantigan-Steffee-Fraser (mBSF) grade. Clinical data on sex, age, body mass index, Meyerding grade, smoking status, follow-up times, complications, and radiological parameters including disc height, disc angle, segmental lordosis, and overall lumbar lordosis were collected. The fusion results and clinical and radiographic data were statistically compared between the ALIF and TLIF groups by using t-test or chi-square test.

RESULTS

The mean follow-up period was 37.5 (ranging from 24 to 51) months. Clear, solid radiographic fusions were higher in the ALIF group compared with the TLIF group at the last follow-up (75% vs 47.9%, p = 0.006). Indeterminate fusion occurred in 20.8% (10/48) of ALIF cases and in 43.8% (21/48) of TLIF cases (p = 0.028). Radiographic pseudarthrosis was not significantly different between the TLIF and ALIF groups (16.7% vs 8.3%; p = 0.677). In subgroup analysis of the patients without bone morphogenetic protein (BMP), the solid radiographic fusion rate was significantly higher in the ALIF group than that in the TLIF group (78.6% vs 45.5%; p = 0.037). There were no differences in sex, age, body mass index, Meyerding grade, smoking status, or follow-up time between the two groups (p > 0.05). The ALIF group had more improvement in disc height (7.8 mm vs 4.7 mm), disc angle (5.2° vs 1.5°), segmental lordosis (7.0° vs 2.5°), and overall lumbar lordosis (4.7° vs 0.7°) compared with the TLIF group (p < 0.05). Overall complication rates were similar between the TLIF and ALIF groups (10.4% vs 8.33%; p > 0.999).

CONCLUSIONS

With a minimum 2-year radiographic analysis of arthrodesis at lumbosacral level by radiologists, the rate of solid radiographic fusions was higher in the ALIF group compared with the TLIF group, whereas the TLIF group had a higher rate of indeterminate fusion. Radiographic pseudarthrosis did not differ significantly between the TLIF and ALIF groups.

Efficacy of oblique lumbar interbody fusion versus transforaminal lumbar interbody fusion in the treatment of lumbar degenerative diseases: a systematic review and meta-analysis

INTRODUCTION

This meta-analysis aimed to compare the differences in postoperative efficacy between oblique lumbar interbody fusion (OLIF) and transforaminal lumbar interbody fusion (TLIF) in the treatment of lumbar degenerative diseases.

MATERIALS AND METHODS

Strictly based on the search strategy, we searched the published papers on OLIF and TLIF for the treatment of lumbar degenerative diseases in PubMed, Embase, CINAHL, and Cochrane Library. A total of 607 related papers were retrieved, and 15 articles were finally included. The quality of the papers was evaluated according to the Cochrane systematic review methodology, and the data were extracted and meta-analyzed using Review manager 5.4 software.

RESULTS

Through comparison, it was found that in the treatment of lumbar degenerative diseases, the OLIF group had certain advantages over the TLIF group in terms of intraoperative blood loss, hospital stay, visual analog scale (VAS) for leg pain (VAS-LP), Oswestry disability index (ODI), disc height (DH), foraminal height (FH), fused segmental lordosis (FSL), and cage height, and the differences were statistically significant. The results were similar in terms of surgery time, complications, fusion rate, VAS for back pain (VAS-BP) and various sagittal imaging indicators, and there was no significant difference.

CONCLUSIONS

OLIF and TLIF can relieve low back pain symptoms in the treatment of lumbar degenerative diseases, but OLIF has certain advantages in terms of ODI and VAS-LP. In addition, OLIF has the advantages of minor intraoperative trauma and quick postoperative recovery.

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.

Perioperative Clinical Features and Long-term Prognosis After Oblique Lateral Interbody Fusion (OLIF), OLIF With Anterolateral Screw Fixation, or OLIF With Percutaneous Pedicle Fixation: A Comprehensive Treatment Strategy for Patients With Lumbar Degenerative Disease

OBJECTIVE

To compare the efficacy of oblique lateral interbody fusion (OLIF), OLIF combined with anterolateral screw fixation (OLIF-AF), and OLIF combined with percutaneous pedicle screw fixation (OLIF-PF) in the treatment of single-level or 2-level degenerative lumbar disease.

METHODS

Between January 2017 and 2021, 71 patients were treated with OLIF and combined OLIF. The demographic data, clinical outcomes, radiographic outcomes, and complications were compared among the 3 groups.

RESULTS

The operative time and intraoperative blood loss in the OLIF (p<0.05) and OLIF-AF (p<0.05) groups were lower than in the OLIF-PF group. Posterior disk height improvement in the OLIF-PF group was better than in the OLIF (p<0.05) and OLIF-AF (p<0.05) groups. In terms of foraminal height (FH), the OLIF-PF group was significantly better than the OLIF group (p<0.05), but there was no significant difference between the OLIF-PF and OLIF-AF groups (p>0.05) or between the OLIF and OLIF-AF groups (p>0.05). There were no significant differences in fusion rates, the incidence of complications, lumbar lordosis, anterior disc height, and cross-sectional area among the 3 groups (p>0.05). The OLIF-PF group had significantly lower rates of subsidence than the OLIF group (p<0.05).

CONCLUSION

OLIF remains a viable option with similar patient-reported outcomes and fusion rates compared with surgeries that include lateral and posterior internal fixation while greatly reducing the financial burden, intraoperative time, and intraoperative blood loss. OLIF has a higher subsidence rate than lateral and posterior internal fixation, but most subsidence is mild and has no adverse effect on clinical and radiographic outcomes.

Mini-Open Intercostal Retroperitoneal Approach for Upper Lumbar Spine Lateral Interbody Fusion

OBJECTIVE

Conventional oblique lumbar interbody fusion (OLIF) approach is possible from the L2/3 to L4/5 levels. However, obstruction of the lower ribs (10th-12th) makes it difficult to maintain disc parallel maneuvers or orthogonal maneuvers. To overcome these limitations, we proposed an intercostal retroperitoneal (ICRP) approach to access the upper lumbar spine. This method does not expose the parietal pleura or require rib resection and employs a small incision.

METHODS

We enrolled patients who underwent a lateral interbody procedure on the upper lumbar spine (L1/2/3). We compared the incidence of endplate injury between conventional OLIF and ICRP approaches. In addition, by measuring the rib line, the difference in endplate injury according to rib location and approach was analyzed. We also analyzed the previous period (2018-2021) and the year 2022, when the ICRP has been actively applied.

RESULTS

A total of 121 patients underwent lateral interbody fusion to the upper lumbar spine (OLIF approach, 99 patients; ICRP approach, 22 patients). Endplate injuries occurred in 34 of 99 (34.3%) and 2 of 22 patients (9.1%) during the conventional and ICRP approaches, respectively (p = 0.037; odds ratio, 5.23). When the rib line was located at the L2/3 disc or L3 body, the endplate injury rate was 52.6% (20 of 38) for the OLIF approach but 15.4% (2 of 13) for the ICRP approach. Since 2022, the proportion of OLIF including L1/2/3 levels has increased 2.9-fold.

CONCLUSION

The ICRP approach is effective in reducing the incidence of endplate injury in patients with a relatively lower rib line, without pleural exposure or rib resection.

Looking Back on 2022 With Neurospine

On behalf of the editorial office of <i>Neurospine</i>, we would like to extend our appreciation to all the readers who have supported the journal throughout the year. <i>Neurospine</i> was established in March 2018 through a collaboration of 3 leading spinal neurosurgery societies from Japan, Korea, and Taiwan. Since then, <i>Neurospine</i> has continued to enhance its academic impact, serving as a platform for sharing knowledge and information related to the management of spinal diseases. In this article, we aim to present the bibliometrics of <i>Neurospine</i>, including the submission and publication of manuscripts and the peer review process. We are looking forward to continued growth and serving the academic community to the best of our ability.

Shape-memory collagen scaffold combined with hyaluronic acid for repairing intervertebral disc

BACKGROUND

Intervertebral disc degeneration (IVDD) is a common cause of chronic low back pain (LBP) and a socioeconomic burden worldwide. Conservative therapies and surgical treatments provide only symptomatic pain relief without promoting intervertebral disc (IVD) regeneration. Therefore, the clinical demand for disc regenerative therapies for disc repair is high.

METHODS

In this study, we used a rat tail nucleotomy model to develop mechanically stable collagen-cryogel and fibrillated collagen with shape-memory for use in minimally invasive surgery for effective treatment of IVDD. The collagen was loaded with hyaluronic acid (HA) into a rat tail nucleotomy model.

RESULTS

The shape-memory collagen structures exhibited outstanding chondrogenic activities, having completely similar physical properties to those of a typical shape-memory alginate construct in terms of water absorption, compressive properties, and shape-memorability behavior. The treatment of rat tail nucleotomy model with shape-memory collagen-cryogel/HA alleviated mechanical allodynia, maintained a higher concentration of water content, and preserved the disc structure by restoring the matrix proteins.

CONCLUSION

According to these results, the collagen-based structure could effectively repair and maintain the IVD matrix better than the controls, including HA only and shape-memory alginate with HA.