In this editorial, the authors of this paper comment on the article by Bokov et al published in the recent issue of World Journal of Orthopedics. We reviewed a general overview of oblique lumbar interbody fusions (OLIF) and lateral lumbar interbody fusions (LLIF), their indications and complications as an increasingly popular minimally invasive technique to address several lumbar pathologies. This editorial thoroughly discusses and reviews the literature regarding factors affecting outcomes of indirect decompression utilized through OLIF and LLIF procedures. Several parameters play a critical role in patient outcomes including restoration of disc height, foraminal height, central canal squared, and foraminal area. The indirect decompression allows for unbuckling of the ligamentum flavum which can significantly decompress the neural elements as well as aid in reduction of spondylolisthesis. However, the authors further highlight the limitations of indirect decompression and factors that may predict unsuccessful outcomes including bony foraminal stenosis, severe central canal stenosis, and osteoporosis. As a result, failure of indirect decompression can lead to persistent pain, radiculopathy and unsatisfied patients. Spinal surgeons may be left to reimage patients and consider additional procedures with direct decompression.

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.

A meta-analysis approach to a systematic review.

Perform a systematic review to identify all reports directly comparing outcomes of lateral lumbar interbody fusion (LLIF) using static versus expandable interbody cages. Specifically focusing on periprocedural complications, intraoperative morbidity, and fusion outcomes.

Minimally invasive surgical techniques, particularly LLIF, have gained popularity for their potential to reduce muscle and soft tissue dissection, leading to faster postoperative recovery. LLIF has been associated with fewer complications compared with open posterior approaches. The introduction of expandable lumbar interbody devices aims to further reduce surgical difficulty and potential complications. However, concerns include a small graft window due to the expansion mechanism and higher costs.

The Web of Science, Scopus, and PubMed databases were systematically queried in accordance with PRISMA guidelines to identify articles comparing outcomes following LLIF using static and expandable interbodies. The Newcastle-Ottawa Scale (NOS) was employed to assess the risk of bias (ROB) in the selected studies. Extracted data underwent effect-size meta-analysis with the PyMARE library, using P<0.05 to define statistical significance.

Of the 77 identified articles, 4 studies comprising 283 patients (mean age: 67.1 y, 55.8% female) met the inclusion and exclusion criteria. A total of 150 patients (53%) were treated with static interbodies compared with 133 (47%) receiving expandable interbodies. The groups did not differ significantly with respect to operative time (P=0.59), blood loss (P=0.89), length of stay (P=0.78), subsidence (P=0.49), 24-month mean disc height (P=0.11), 24-month mean ODI (P=0.58), or 24-month mean visual analog scale (VAS) back pain (P=0.81). The expandable group saw a trend toward improved fusion rates (97% vs. 92%, P=0.06).

The present meta-analysis suggests the use of expandable (vs. static) interbodies in LLIF surgery may result in similar surgical morbidity, subsidence, and decompression. Further prospective comparative studies are merited to validate these results.

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

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.

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%).

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.

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.

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.

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.

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.

Oblique lateral interbody fusion (OLIF) is a minimally invasive procedure for stabilizing the spine and indirectly decompressing the neural elements. There is sparse data on unsatisfactory outcomes that require additional interventions (surgery or intervention) after OLIF. This study aimed to identify the causes, and risk factors of these reintervention.

This was a single-center retrospective study of the patients who underwent the OLIF procedure from June 2016 to March 2023. Several clinical and radiographic parameters were studied. We also analyzed associations between several potential risk factors and the reintervention following OLIF.

A total of 231 patients were included. Over an average of 2.5 years of follow-up, 28 patients (12.1%) required a reintervention. Adjacent segment disease (ASD) was the most common cause of reintervention. The risk factors associated with reintervention were previous surgery (adjusted odds ratio [aOR], 4.44; 95% confidence interval [CI], 1.21-16.33; p=0.02) and high preoperative Oswestry Disability Index (ODI) scores (aOR, 1.04; 95% CI, 1.00-1.08; p=0.03). Although increasing the duration of follow-up was not statistically significant, the 95% CI was consistent with an increased risk of reintervention with longer follow-up (OR, 1.18; 95% CI, 0.94-1.50).

This study showed that patients with prior lumbar surgery and high preoperative ODI scores were more likely to require additional intervention after the OLIF procedure. In addition, an increasing duration of follow-up was associated with an increased risk of reintervention. The most common reason for reintervention was ASD after OLIF.

This retrospective study assesses the influence of osteoporosis on the short-term clinical outcomes of lateral lumbar interbody fusion (LLIF) surgery in patients with lumbar degenerative diseases (LDDs), focusing on complications, pain intensity, and quality of life (QOL) improvements. The primary aim of this study is to investigate the impact of osteoporosis on the short-term clinical outcomes following LLIF surgery in LDD patients, with a particular focus on the incidence of cage subsidence (CS) and overall patient well-being postoperatively.

A retrospective review was conducted on 73 patients who underwent LLIF for LDD. Patients were categorized into 2 groups based on osteoporosis status determined by dual-energy X-ray absorptiometry scans: those with osteoporosis (n = 20) and those without osteoporosis (n = 53). Data collection included demographics, surgical details, complications, magnetic resonance imaging analysis, pain intensity, and QOL (Japanese Orthopaedic Association Back Pain Evaluation Questionnaire).

The groups had no significant differences regarding operative time, estimated blood loss, and hospital stay duration. However, the incidence of CS was 40% in patients with osteoporosis, compared to 17% in nonosteoporotic patients. Despite this, significant improvements in spinal canal dimensions were observed in both groups. Both groups experienced significant reductions in pain intensity, with notable improvements in functional outcomes assessed by the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, indicating the overall effectiveness of LLIF in enhancing patient well-being and functionality, irrespective of osteoporosis status.

Osteoporosis increases the risk of CS in LLIF surgery for LDD patients but does not affect short-term pain relief and QOL improvements.

To compare the clinical and radiographic outcomes following lateral lumbar interbody fusion (LLIF) between direct and indirect decompression in the treatment of patients with degenerative lumbar diseases.

Patients who underwent single-level LLIF were randomized into 2 groups: direct decompression (group D) and indirect decompression (group I). Clinical outcomes including the Oswestry Disability index and visual analogue scale of back and leg pain were collected. Radiographic outcomes including cross-sectional area (CSA) of thecal sac, disc height, foraminal height, foraminal area, fusion rate, segmental, and lumbar lordosis were measured.

Twenty-eight patients who met the inclusion criteria were eligible for the analysis, with a distribution of 14 subjects in each group. The average age was 66.1 years. Postoperatively, significant improvements were observed in all clinical parameters. However, these improvements did not show significant difference between both groups at all follow-up periods. All radiographic outcomes were not different between both groups, except for the increase in CSA which was significantly greater in group D (77.73 ± 20.26 mm2 vs. 54.32 ± 35.70 mm2, p = 0.042). Group I demonstrated significantly lower blood loss (68.13 ± 32.06 mL vs. 210.00 ± 110.05 mL, p < 0.005), as well as shorter operative time (136.35 ± 28.07 minutes vs. 182.18 ± 42.67 minutes, p = 0.002). Overall complication rate was not different.

Indirect decompression through LLIF results in comparable clinical improvement to LLIF with additional direct decompression over 1-year follow-up period. These findings suggest that, for an appropriate candidate, direct decompression in LLIF might not be necessary since the ligamentotaxis effect achieved through indirect decompression appears sufficient to relieve symptoms while diminishing blood loss and operative time.

Investigate the immediate resonance magnetic image changes undergone by the lumbar canal after indirect decompression and compare them at one-year post-intervention. We also investigate the clinical outcome of indirect decompression at one-year follow-up.

Imaging changes in patients who underwent indirect lumbar decompression and percutaneous posterior fixation were analyzed with one-year follow-up. Radiographic measurements were performed preoperatively and postoperatively (at one year), and the area of lumbar canal occupation and yellow ligament by nuclear magnetic resonance was compared preoperatively, at 48 hours post-surgery, and at one year. Radiographic measurements included disc height, foraminal height, total lumbar lordosis, and segmental lordosis. The VAS lumbar and lower limb scales and the Oswestry Disability Index (ODI) were used to assess clinical outcomes.

A total of 21 male and 23 female patients underwent indirect decompression at 64 lumbar levels. A significant improvement was observed in the clinical evaluation of all patients' post-surgery (p < 0.001) in all radiographic parameters. There was an immediate increase in the lumbar canal at 48 hours (p < 0.001), which continued to increase at one year post-intervention (p < 0.05). The yellow ligament occupation area decreased at 48 hours (p < 0.001) and continued to decrease until one year (p < 0.01). Four complications were recorded, one of which was a posterior tract infection requiring open decompression.

Indirect decompression for degenerative lumbar disease provided successful clinical outcomes, including indirect expansion of the dural sac at 48 hours post-procedure, with progressive increase in the lumbar canal area at one-year follow-up.

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).

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).

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.

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.

Functionally enhanced mesenchymal stromal cells participate in the repair of intervertebral disc. This study aimed to assess the safety and tolerability of intradiscal administration of matrilin-3-primed adipose-derived stromal cell (ASC) spheroids with hyaluronic acid (HA) in patients with chronic discogenic low back pain (LBP). In this single-arm, open-label phase I clinical trial, eight patients with chronic discogenic LBP were observed over 6 months. Each patient underwent a one-time intradiscal injection of 1 mL of 6.0 × 106 cells/disc combined with HA under real-time fluoroscopic guidance. Safety and feasibility were gauged using Visual Analogue Scale (VAS) pain and Oswestry Disability Index (ODI) scores and magnetic resonance imaging. All participants remained in the trial, with no reported adverse events linked to the procedure or stem cells. A successful outcome-marked by a minimum 2-point improvement in the VAS pain score and a 10-point improvement in ODI score from the start were observed in six participants. Although the modified Pfirrmann grade remained consistent across all participants, radiological improvements were evident in four patients. Specifically, two patients exhibited reduced high-intensity zones while another two demonstrated decreased disc protrusion. In conclusion, the intradiscal application of matrilin-3-primed ASC spheroids with HA is a safe and feasible treatment option for chronic discogenic LBP.

The therapeutic potential of Mesenchymal stem cells (MSCs) for the treatment of Intervertebral disc (IVD) degeneration can be enhanced by amplifying specific cytokines and proteins. This study aimed to investigate the therapeutic potential of tetracycline-off system-engineered tonsil-derived mesenchymal stem cells (ToMSC-Tetoff-TGFβ1-IGF1-BMP7) for treating intervertebral disc (IVD) degeneration. ToMSCs were isolated from a tonsillectomy patient and genetically modified with four distinct plasmids via CRISPR/Cas9-mediated knock-in gene editing. Transgene expression was confirmed through immunofluorescence, western blots, and an enzyme-linked immunosorbent assay for transforming growth factor beta 1 (TGFβ1) protein secretion, and the effect of MSC-TetOff-TGFβ1-IGF1-BMP7 on disc injury was assessed in a rat model. The ToMSC-Tetoff-TGFβ1-IGF1-BMP7 treatment exhibited superior therapeutic effects compared to ToMSC-TGFβ1, and ToMSC-SDF1α implantation groups, stimulating the regeneration of nucleus pulposus (NP) cells crucial for IVD. The treatment showed potential to restore the structural integrity of the extracellular matrix (ECM) by upregulating key molecules such as aggrecan and type II collagen. It also exhibited anti-inflammatory properties and reduced pain-inducing neuropeptides. ToMSC-Tetoff-TGFβ1-IGF1-BMP7 holds promise as a novel treatment for IVD degeneration. It appears to promote NP cell regeneration, restore ECM structure, suppress inflammation, and reduce pain. However, more research and clinical trials are required to confirm its therapeutic potential.

Degeneration of fibrocartilaginous tissues is often associated with complex pro-inflammatory factors. These include reactive oxygen species (ROS), cell-free nucleic acids (cf-NAs), and epigenetic changes in immune cells. To effectively control this complex inflammatory signaling, it developed an all-in-one nanoscaffold-based 3D porous hybrid protein (3D-PHP) self-therapeutic strategy for treating intervertebral disc (IVD) degeneration. The 3D-PHP nanoscaffold is synthesized by introducing a novel nanomaterial-templated protein assembly (NTPA) strategy. 3D-PHP nanoscaffolds that avoid covalent modification of proteins demonstrate inflammatory stimuli-responsive drug release, disc-mimetic stiffness, and excellent biodegradability. Enzyme-like 2D nanosheets incorporated into nanoscaffolds further enabled robust scavenging of ROS and cf-NAs, reducing inflammation and enhancing the survival of disc cells under inflammatory stress in vitro. Implantation of 3D-PHP nanoscaffolds loaded with bromodomain extraterminal inhibitor (BETi) into a rat nucleotomy disc injury model effectively suppressed inflammation in vivo, thus promoting restoration of the extracellular matrix (ECM). The resulting regeneration of disc tissue facilitated long-term pain reduction. Therefore, self-therapeutic and epigenetic modulator-encapsulated hybrid protein nanoscaffold shows great promise as a novel approach to restore dysregulated inflammatory signaling and treat degenerative fibrocartilaginous diseases, including disc injuries, providing hope and relief to patients worldwide.

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.

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.

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).

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.

To evaluate the clinical and radiological efficacy of a combine of lateral single screw-rod and unilateral percutaneous pedicle screw fixation (LSUP) for lateral lumbar interbody fusion (LLIF) in the treatment of spondylolisthesis.

Sixty-two consecutive patients with lumbar spondylolisthesis who underwent minimally invasive (MIS)-TLIF with bilateral pedicle screw (BPS) or LLIF-LSUP were retrospectively studied. Segmental lordosis angle (SLA), lumbar lordosis angle (LLA), disc height (DH), slipping percentage, the cross-sectional areas (CSA) of the thecal sac, screw placement accuracy, fusion rate and foraminal height (FH) were used to evaluate radiographic changes postoperatively. Visual analogue scale (VAS) and Oswestry Disability Index (ODI) were used to evaluate the clinical efficacy.

Patients who underwent LLIF-LSUP showed shorter operating time, less length of hospital stay and lower blood loss than MIS-TLIF. No statistical difference was found between the 2 groups in screw placement accuracy, overall complications, VAS, and ODI. Compared with MIS-TLIF-BPS, LLIF-LSUP had a significant improvement in sagittal parameters including DH, FH, LLA, and SLA. The CSA of MIS-TLIF-BPS was significantly increased than that of LLIF-LSUP. The fusion rate of LLIF-LSUP was significantly higher than that of MIS-TLIF-BPS at the follow-up of 3 months postoperatively, but there was no statistical difference between the 2 groups at the follow-up of 6 months, 9 months, and 12 months.

The overall clinical outcomes and complications of LLIF-LSUP were comparable to that of MIS-TLIF-BPS in this series. Compared with MIS-TLIF-BPS, LLIF-LSUP for lumbar spondylolisthesis represents a significantly shorter operating time, hospital stay and lower blood loss, and demonstrates better radiological outcomes to maintain lumbar lordosis, and reveal an overwhelming superiority in the early fusion rate.

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.

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.

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.

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.

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.

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.

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.

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.

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

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

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

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

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

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

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

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