Nuances of oblique lumbar interbody fusion at L5-S1: Three case reports

BACKGROUND

Oblique lumbar interbody fusion is a mini-open retroperitoneal approach that uses a wide corridor between the left psoas muscle and the aorta above L5. This approach avoids the limitations of lateral lumbar interbody fusion, is considered less invasive than anterior lumbar interbody fusion, and is similarly effective for indirect decompression and improving lordosis while maintaining a low complication profile. Including L5-S1, when required, adds to these advantages, as this allows single-position surgery. However, variations in vascular anatomy can affect the ease of access to the L5-S1 disc. The nuances of three different oblique anterolateral techniques to access L5-S1 for interbody fusion, namely, left-sided intra-bifurcation, left-sided pre-psoas, and right-sided pre-psoas approaches, are illustrated using three representative case studies.

CASE SUMMARY

Cases of three patients who underwent multilevel oblique lumbar interbody fusion including L5-S1, using one of the three different techniques, are described. All patients presented with symptomatic degenerative lumbar pathology and failed conservative management prior to surgery. The anatomical considerations that affected the decisions to utilize each approach are discussed. The pros and cons of each approach are also discussed. A parasagittal facet line objectively assesses the relationship between the left common iliac vein and the L5-S1 disc and assists in choosing the approach to L5-S1.

CONCLUSION

Oblique retroperitoneal access to L5-S1 in the lateral decubitus position is possible through three different approaches. The choice of approach to L5-S1 may be individualized based on a patient’s vascular anatomy using preoperative imaging. While most surgeons will rely on their experience and comfort level in choosing the approach, this article elucidates the nuances of each technique.

Salvage Oblique Lateral Interbody Fusion for Pseudarthrosis after Posterior/Transforaminal Lumbar Interbody Fusion: A Technical Note

OBJECTIVE

This study aims to demonstrate the efficacy of salvage oblique lumbar interbody fusion (OLIF) surgery for pseudarthrosis after posterior/transforaminal lumbar interbody fusion (PLIF/TLIF).

METHODS

The study group were patients with leg or back pain induced by pseudarthrosis after PLIF/TLIF. These patients underwent salvage OLIF surgeries in our institutions between July 2015 and Oct 2019. We retrospectively evaluated their clinical and radiographic outcomes.

RESULTS

Seven consecutive patients (all male; mean age 68.4 ± 9.3 years, range 53-81 years) were included in this study. There was no intraoperative complications in all cases. Six of 7 patients achieved bone union (at average 33.4 months follow-up) and had a successful postoperative course. Only 1 patient failed to gain bony fusion and required additional revision surgery due to progression of sagittal and coronal malalignment at 18 months after salvage OLIF surgery.

CONCLUSIONS

The salvage OLIF approach was useful option for pseudarthrosis after PLIF/TLIF. It enabled us to build a rigid anterior support, allowed for extensive curettage of intervertebral scar tissue, and reduced the rate of the complications associated with dealing with posterior scar tissue.

Treatment of Degenerative Lumbar Scoliosis with Oblique Lumbar Interbody Fusion in Conjunction with Unilateral Pedicle Screw Fixation via the Wiltse Approach

Objective

To evaluate the clinical outcomes of oblique lumbar interbody fusion (OLIF) in conjunction with unilateral pedicle screw fixation (UPSF) via the Wiltse approach in treating degenerative lumbar scoliosis (DLS).

Methods

The article is a retrospective analysis. Twelve patients with DLS who underwent combined OLIF and UPSF between July 2017 and December 2018 were included. The study included 2 male and 10 female patients, with a mean age at the time of the operation of 67.2 ± 9.1 years. The surgical characteristics and complications were evaluated. The clinical and radiological data such as the correction of deformity, coronal and sagittal profile were analyzed.

Results

The mean follow‐up time of the study was 26.8 ± 1.8 months. At the final follow‐up, all patients who underwent combined OLIF and UPSF achieved statistically significant improvements in coronal Cobb angle (from 19.6° ± 4.8° to 6.9° ± 3.8°, P < 0.01), distance between the C7 plumb line and central sacral vertebral line (from 2.5 ± 1.7 cm to 0.9 ± 0.6 cm, P < 0.01), sagittal vertebral axis (from 4.3 ± 4.3 cm to 1.5 ± 1.0 cm, P = 0.03), lumbar lordosis (from 29.4° ± 8.6° to 40.8° ± 5.8°, P < 0.01), pelvic tilt (from 27.6° ± 10.8° to 18.3° ± 7.0°, P < 0.01), pelvic incidence‐lumbar lordosis mismatch (from 23.3° ± 10.5° to 11.9° ± 8.4°, P < 0.01), and cross‐sectional area of the dural sac (from 87.33 ± 39.41 mm² to 124.70 ± 39.26 mm², P < 0.01). The visual analogue score for back and leg pain and Oswestry Disability Index of all patients significantly improved postoperatively (P < 0.01). One case of lumbar plexus injury was found after surgery. During the follow‐up period, one patient had cage subsidence. A fusion rate of 100% and good positioning of the pedicle screws were achieved in all patients at the final follow‐up.

Conclusion

OLIF in conjunction with UPSF is a safe and effective minimally invasive procedure for correcting both coronal and sagittal deformities, as it results in an improved quality of life in patients with DLS.

Comparison of Clinical Outcomes and Complications of Primary and Revision Surgery Using a Combined Anterior and Posterior Approach in Patients with Adult Spinal Deformity and Sagittal Imbalance

Backgroud

The purpose of this study was to compare clinical outcomes and complications of primary and revision surgery in patients with adult spinal deformity (ASD) accompanied by sagittal imbalance. Revision surgery has been associated with poor clinical outcomes and increased risk of complications. Previous studies comparing primary versus revision surgery included data for a wide variety of diseases and ages, but few investigated patients with ASD with sagittal imbalance undergoing anterior and posterior combined surgery.

Methods

Retrospective cohort analysis of prospectively collected data. We identified 60 consecutive patients with ASD combined with sagittal imbalance who underwent primary or revision surgery; of these, 6 patients were excluded for lack of a minimal 2-year follow-up. Patients' surgical and radiological data, clinical outcomes, and complications were reviewed.

Results

There were 30 patients in the primary group and 24 patients in the revision group. Patient characteristics, including the prevalence of sarcopenia, were similar between the two groups. Pedicle subtraction osteotomy was performed more frequently in the revision group although there was no statistically significant difference between groups. The primary group had more proximal junctional problems, whereas the revision group had more rod breakage (p < 0.05). There were significant improvements in clinical outcomes in both groups when the preoperative and 2-year postoperative values were compared. The Oswestry disability index and visual analog scale score were similar in both groups 2 years postoperatively.

Conclusions

Considering the greater pain and disability at the time of the revision procedure, revision patients benefited more from surgery at the 2-year follow-up than the primary surgery patients. Complication rates were similar between the groups except for proximal junctional problems and rod breakage. Therefore, revision surgery should not be avoided in the treatment of ASD patients with sagittal imbalance.

Inclusion of L5-S1 in oblique lumbar interbody fusion-techniques and early complications-a single center experience

BACKGROUND CONTEXT

The oblique prepsoas retroperitoneal approach to the lumbar spine for interbody fusion or oblique lumbar interbody fusion (OLIF) provides safe access to nearly all lumbar levels. A wide interval between the psoas and aorta allows for a safe and straightforward left-sided oblique approach to the discs above L5. Inclusion of L5-S1 in this approach, however, requires modifications in the technique to navigate the complex and variable vascular anatomy distal to the bifurcation of the great vessels. While different oblique approaches to L5-S1 have been described in the literature, to our knowledge, no previous study has provided guidance for the choice of technique.

PURPOSE

Our objectives were to evaluate our early experience with the safety of including L5-S1 in OLIF using 3 different approach techniques, as well as to compare early complications between OLIF with and without L5-S1 inclusion.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

Of the 87 patients who underwent lumbar interbody fusion at 167 spinal levels via an OLIF approach, 19 included L5-S1 (group A) and 68 did not (group B).

OUTCOME MEASURES

Demographics, levels fused, indications, operative time (ORT), estimated blood loss (EBL), vascular ligation, intraoperative blood transfusion, length of stay (LOS), discharge to rehabilitation facility, and complications (intraoperative, early ≤90 days, and delayed >90 days) were retrospectively assessed and compared between the groups.

METHODS

A retrospective chart and imaging review of all consecutive patients who underwent OLIF at a single institution was performed. Indications for OLIF included symptomatic lumbar degenerative stenosis, deformity, and spondylolisthesis. The L5-S1 level, when included, was approached via one of the following 3 techniques: (1) a left-sided intrabifurcation approach; (2) left-sided prepsoas approach; and (3) right-sided prepsoas approach. Vascular anatomic variations at the lumbosacral junction were evaluated using the preoperative magnetic resonance imaging (MRI), and a "facet line" was proposed to assess this relationship. A minimum of 6 months of follow-up data were assessed for approach-related morbidities.

RESULTS

Demographics and operative indications were similar between the groups. The mean follow-up was 10.8 (6-36) months. ORT was significantly longer in group A than in group B (322 vs. 256.3 min, respectively; p=.001); however, no difference in ORT between the two groups was found in the subanalyses for 2- and 3-level surgeries. Differences in EBL (260 vs. 207.91 cc, p=.251) and LOS (2.76 vs. 2.48 days, p=.491) did not reach statistical significance. Ligation of the iliolumbar vein, segmental veins, median sacral vessels, or any vascular structure, as needed for adequate exposure, was required in 13 (68.4%) patients from group A and 4 (5.9%) from group B (p<.00001). Two patients suffered minor vascular injuries (1 in each group); however, no major vascular injuries were seen. Complications were not significantly different between groups A and B, or between the three approaches to L5-S1, and trended lower in the latter part of the series as the learning curve progressed.

CONCLUSIONS

Inclusion of L5-S1 in OLIF is safe and feasible through three different approaches but likely involves greater operative complexity. In our early experience, inclusion of L5-S1 showed no increase in early complications. This is the first series that reports the use of 3 different oblique approaches to L5-S1. The proposed "facet line" in the preoperative MRI may guide the choice of approach.

Biomechanical Evaluation of Oblique Lumbar Interbody Fusion with Various Fixation Options: A Finite Element Analysis

Objective

The aim of the present study was to clarify the biomechanical properties of oblique lumbar interbody fusion (OLIF) using different fixation methods in normal and osteoporosis spines.

Methods

Normal and osteoporosis intact finite element models of L₁–S₁ were established based on CT images of a healthy male volunteer. Group A was the normal models and group B was the osteoporosis model. Each group included four subgroups: (i) intact; (ii) stand‐alone cage (Cage); (iii) cage with lateral plate and two lateral screws (LP); and (iv) cage with bilateral pedicle screws and rods (BPSR). The L₃–L₄ level was defined as the surgical segment. After validating the normal intact model, compressive load of 400 N and torsional moment of 10 Nm were applied to the superior surface of L₂ to simulate flexion, extension, left bending, right bending, left rotation, and right rotation motions. Surgical segmental range of motion (ROM), cage stress, endplate stress, supplemental fixation stress, and stress distribution were analyzed in each group.

Results

Cage provided the minimal reduction of ROM among all motions (normal, 82.30%–98.81%; osteoporosis, 92.04%–97.29% of intact model). BPSR demonstrated the maximum reduction of ROM (normal, 43.94%–61.13%; osteoporosis, 45.61%–62.27% of intact model). The ROM of LP was between that of Cage and BPSR (normal, 63.25%–79.72%; osteoporosis, 70%–87.15% of intact model). Cage had the minimal cage stress and endplate stress. With the help of LP and BPSR fixation, cage stress and endplate stress were significantly reduced in all motions, both in normal and osteoporosis finite element models. However, BPSR had more advantages. For cage stress, BPSR was at least 75.73% less than that of Cage in the normal model, and it was at least 80.10% less than that of Cage in the osteoporosis model. For endplate stress, BPSR was at least 75.98% less than that of Cage in the normal model, and it was at least 78.06% less than that of Cage in the osteoporosis model. For supplemental fixation stress, BPSR and LP were much less than the yield strength in all motions in the two groups. In addition, the comparison between the two groups showed that the ROM, cage stress, endplate stress, and supplemental fixation stress in the normal model were less than in the osteoporosis model when using the same fixation option of OLIF.

Conclusion

Oblique lumbar interbody fusion with BPSR provided the best biomechanical stability both in normal and osteoporosis spines. The biomechanical properties of the normal spine were better than those of the osteoporosis spine when using the same fixation option of OLIF.

Usefulness of Oblique Lumbar Interbody Fusion as Revision Surgery: Comparison of Clinical and Radiological Outcomes Between Primary and Revision Surgery

OBJECTIVE

Oblique lumbar interbody fusion (OLIF) is useful as surgical treatment of degenerative lumbar disease. However, revision surgery has often resulted in worse surgical outcomes than primary surgery. Thus, we compared the usefulness of OLIF as primary surgery (PS) versus revision surgery (RS).

METHODS

We retrospectively investigated 173 patients who had undergone single-level OLIF from 2016 to 2018. The radiological and clinical outcomes were compared between PS (n = 152) and RS (n = 21). The effects of RS on the clinical outcomes (Oswestry Disability Index [ODI] cutoff, 12) after surgery were investigated.

RESULTS

The ODI and visual analog scale score at 6 and 12 months after surgery was worse in the RS group than in the PS group (P < 0.05). In the RS group, the visual analog scale score for leg pain of the previous laminectomy side was worse than that of the virgin side at 6 and 12 months after surgery (P < 0.05). The disc height, ligamentum flavum, and subsidence did not differ between the 2 groups. However, the cross-sectional area enlargement differed between the 2 groups (P < 0.05). Multivariate logistic regression analysis showed that RS and severe subsidence were risk factors for differences in the ODI (P = 0.006 and P = 0.017, respectively).

CONCLUSIONS

Most radiological outcomes were similar between the RS and PS groups, with no differences in complications or the requirement for additional posterior decompression. However, OLIF resulted in relatively poor clinical outcomes when used as RS. Thus, revision spine surgery tends to result in poor outcomes compared with those of primary spine surgery; however, OLIF can be a tolerable option for revision spine surgery.

Does oblique lumbar interbody fusion promote adjacent degeneration in degenerative disc disease: A finite element analysis

BACKGROUND

The number of oblique lumbar interbody fusion (OLIF) procedures has continued to rise over recent years. Adjacent segment degeneration (ASD) is a common complication following vertebral body fusion. Although the precise mechanism remains uncertain, ASD has gradually become more common in OLIF. Therefore, the present study analyzed the association between disc degeneration and OLIF to explore whether adjacent degeneration was promoted by OLIF in degenerative disc disease.

METHODS

A three-dimensional nonlinear finite element (FE) model of the L3-S1 lumbar spine was developed and validated. Three lumbar spine degeneration models with different degrees of degeneration (mild, moderate and severe) and a model of OLIF surgery were constructed at the L4-L5 level. When subjected to a follower compressive load (500 N), hybrid moment loading was applied to all models of the lumbar spine and the range of motion (ROM), intradiscal pressure (IDP), facet joint force (FJF), average mises stress in the annulus (AMSA), average tresca stress in the annulus (ATSA) and average endplate stress (AES) were measured.

RESULTS

Compared with the healthy lumbar spine model, the ROM, IDP, FJF, AMSA, ATSA and AES of the segments adjacent to the degenerated segment increased in each posture as the degree of disc degeneration increased. In different directions of motion, the ROM, IDP, FJF, AMSA, ATSA and AES in the OLIF model in the L3-L4 and L5-S1 segments were higher than those of the healthy model and each degenerated model. Compared with the healthy model, the largest relative increase in biomechanical parameters above (ROM, IDP, FJF, AMSA, ATSA or AES) was observed in the L3-L4 segment in the OLIF model, of 77.13%, 32.63%, 237.19%, 45.36%, 110.92% and 80.28%, respectively. In the L5-S1 segment the corresponding values were 68.88%, 36.12%, 147.24%, 46.00%, 45.88% and 51.29%, respectively.

CONCLUSIONS

Both degenerated discs and OLIF surgery modified the pattern of motion and load distribution of adjacent segments (L3-L4 and L5-S1 segments). The increases in the biomechanical parameters of segments adjacent to the surgical segment in the OLIF model were more apparent than those of the degenerated models. In summary, OLIF risked accelerating the degeneration of segments adjacent to those of a surgical segment.

[Research progress of ureteral injury in oblique lumbar interbody fusion]

Objective

To summarize the research progress of ureteral injury in oblique lumbar interbody fusion (OLIF).

Methods

The literature about incidence, clinical manifestations, diagnosis, and treatment of ureteral injury complications in OLIF was reviewed.

Results

OLIF surgery poses a risk of ureteral injury because its surgical approach is anatomically adjacent to the left ureter. Ureteral injuries in OLIF are often insidious and have no specific clinical manifestations. CT urography is a common diagnostic method. The treatment of ureteral injury depends on a variety of factors such as the time of diagnosis, the location and degree of injury, and the treatment methods range from endoscopic treatment to replacement reconstruction.

Conclusion

Surgeons should pay attention not to damage the ureter and find the abnormality in time during OLIF. High vigilance of abnormalities is conducive to the early diagnosis of ureteral injury. Furthermore, it is important to be familiar with ureter anatomy and gentle operation to prevent ureteral injury.

The correlation of intraoperative distraction of intervertebral disc with the postoperative canal and foramen expansion following oblique lumbar interbody fusion

PURPOSE

To examine the correlation of intraoperative distraction of intervertebral disc with the postoperative central canal and foramen expansion by oblique lumbar interbody fusion (OLIF) with indirect decompression.

METHODS

Patients who underwent OLIF between October 2013 and April 2017 were included. Clinical outcomes included back and leg pain evaluated by visual analog scale (VAS) and Oswestry Disability Index (ODI). Intraoperative radiographic parameters of height ratio [(HR) = disc height/intervertebral body height)] and cage location were evaluated on intraoperative fluoroscopic images. Disc height (DH), foraminal height (FH), cross-sectional area of spinal canal (CSAC), and CSA of the foramen (CSAF) were measured.

RESULTS

A total of 47 patients involving 62 levels were enrolled in this study. Mean follow-up was 43.8 ± 12.0 months. These patients reported an improvement of 61.7% in VAS back, 68.1% in VAS leg, and 46% in ODI (all p < 0.01). Radiographic parameters including HR, DH, FH, CSAC, and CSAF were also significantly increased by 32.6%, 48.2%, 21.4%, 44.0%, and 40.1% (left-side CSAF) or 45.4% (right-side CSAF), respectively (p < 0.05). HR increment was correlated with CSA (canal and foramen) increment. Slightly higher improvements of HR, DH, FH, CSAC, and CSAF (both sides) were noted when cage was located at middle rather than anterior (p > 0.05).

CONCLUSIONS

The ligamentotaxis effect of OLIF is capable of supporting indirect decompression of central canal and neural foramina and clinical improvement. HR is a reliable intraoperative assessment method. In addition, intraoperative HR increment was correlated with postoperative neural elements expansion.

Efficacy and radiographic analysis of oblique lumbar interbody fusion in treating lumbar degenerative spondylolisthesis with sagittal imbalance

The aim of this study was to evaluate the effectiveness of OLIF (oblique lumbar interbody fusion) in the treatment of lumbar degenerative spondylolisthesis with sagittal imbalance. Fifty-nine patients were included in our analysis. Included patients were divided into 2 groups according to the surgical techniques: PLIF (posterior lumbar interbody fusion) (n = 31) and OLIF + PSF (OLIF combined with posterior spinal fixation) (n = 28). Perioperative radiographic parameters, complications, and clinical outcome from each group were assessed and compared. The operation time for both groups was 165.1 min in the OLIF group and 182.1 min in the PLIF group (P < 0.05). The intraoperative blood loss was 190.6 ml in the OLIF group and 356.3 ml in the PLIF group (P < 0.05). The number of intraoperative and postoperative complications for both groups was 7 in the OLIF group and 11 in the PLIF group. Significant clinical improvement was observed in VAS scores and ODI when comparing preoperative evaluation and final follow-up. The preoperative SVA (the distance from the posterosuperior corner of S1body to the C7 plumb line), PI (pelvic incidence), LL (lumbar lordosis), PI-LL mismatch, DH (disc height), and lumbar Cobb angles of both groups were similar. The postoperative and final follow-up SVA, LL, PI-LL mismatch, and disc height were improved in both groups, and a statistical difference was found between both groups (P < 0.05). An improvement of SVA, LL, PI-LL mismatch, and disc height at the OLIF group was better than that found at the PLIF group. An improvement in radiographic and clinical outcomes for the OLIF group was better than that seen for the PLIF group. Then, OLIF had a more curative effect in lumbar degenerative spondylolisthesis with sagittal imbalance.

[Clinical and radiographic evaluation of oblique lumbar interbody fusion combined with posterior surgery via Wiltse approach for adult degenerative scoliosis]

Objective: To assess the clinical effect of oblique lumbar interbody fusion (OLIF) combined with posterior surgery via Wiltse approach for adult degenerative scoliosis. Methods: The clinical data of 27 patients with adult degenerative scoliosis who received OLIF operation from April 2015 to June 2018 in Tongji Hospital were analyzed retrospectively. There were 17 males and 10 females with an average age of (54±11) years. All patients were treated with OLIF combined with pedicle screw fixation via Wiltse approach. Operation time, blood loss and surgery complications were all recorded. Clinical and radiographic evaluation were investigated at 1 week, 3 months of post operation and final follow-up. Visual analog scale (VAS) for low back pain and leg pain, Oswestry disability index (ODI) for low back pain were used to evaluate the clinical efficacy of surgery. Lumbar coronal cobb angle, lumbar lordosis (LL), pelvic tilt (PT), mismatch of PI and PT, sagittal vertical axis (SVA) were investigated with full spine standing X-ray. The data were compared with factor analysis of variance. Results: All patients were followed-up for 6-52 months ((30±5) months). The operation time was (235±33) min, the blood loss was (433±62) ml. VAS for low back pain and eg pain and the ODI were significantly improved from 6.8±1.4, 7.3±1.4 and 71%±11% preoperatively to 1.1±1.2, 1.0±0.9 and 17%±6% at the latest follow-up (F=115.302,139.855,291.198, all P<0.05).Lumbar coronal Cobb angle of patients was reduced from 28°±8° preoperatively to 9°±4° at the latest follow-up (F=66.352, P<0.05). The LL was significantly increased from 20°±11° preoperatively to 33°±7° (F=17.678, P<0.05), and PT, PI-LL and SVA were significantly increased from 31°±6°,35°±12° and (90±29) mm preoperatively to 26°±5°, 21°±6° and (32±17) mm at the latest follow-up (F=6.211,23.809,53.372, all P<0.05). There was no severe vascular andnerve injuries during and after operation. Conclusion: OLIF combined with posterior surgery via Wiltse approach is a safe and effective operation in the treatment of adult degenerative scoliosis with mild to moderate sagittal imbalance, it can correct the coronal and sagittal deformity, and achieve less surgery injury, less complications and good clinical results.

Minimally Invasive Surgery Oblique Lumbar Interbody Debridement and Fusion for the Treatment of Lumbar Spondylodiscitis

Objective

To evaluate the efficacy and feasibility of minimally invasive oblique lumbar interbody debridement and fusion for the treatment of conservatively ineffective lumbar spondylodiscitis.

Methods

This is a retrospective study. Between December 2016 and November 2017, a total of 14 consecutive patients (eight males and six females, with an average age of 49.1 years, range from 42 to 74 years) with single‐level lumbar spondylodiscitis were included in the study. The inclusion criteria include single‐level spondylodiscitis without spinal deformity or epidural abscess, ineffective conservative treatment (continuously aggravated clinical symptoms and uncontrollable infective symptoms treated with antibiotics for more than 6 weeks), minimally invasive oblique lumbar interbody fusion surgery (Mis‐OLIF) and iliac graft for the treatment of lumbar spondylodiscitis, and postoperative follow‐up >12 months. Each patient was treated Mis‐OLIF. Clinical outcomes including demographic characteristics, erythrocyte sedimentation rate (ESR), C‐reactive protein (CRP), visual analog scale (VAS), the Oswestry Disability Index (ODI), American Spinal Injury Association neurological classification, and lordotic angle were analyzed.

Results

The infectious levels included L1/2 (one patient), L2/3 (two patients), L3/4 (eight patients), and L4/5 (three patients). The pathogens found in these patients included Staphylococcus aureus (5), brucellosis (6), and enterobacterium (2). The pathogen was undefined in one patient. The mean duration of the surgery, mean blood loss, and mean follow‐up were 89.3 ± 17.5 min, 155.0 ± 49.4 mL, and 16.8 ± 4.2 months, respectively. The ESR and CRP decreased after Mis‐OLIF and antibiotic administration. The average preoperative VAS score was 6.9 ± 0.9, then decreased to 3.0 ± 1.0 (t = 14.18, P < 0.001) and 0.6 ± 0.7 (t = 20.68, P < 0.001) before discharge and at final follow‐up, respectively. The average preoperative ODI score was 58.4 ± 13.0, then decreased to 28.3 ± 6.1 (t = 18.6, P < 0.001) and 8.0 ± 4.6 (t = 22.7, P < 0.001) before discharge and at final follow‐up, respectively. None of the patients developed postoperative ileus, vascular injury, nerve injury, and ureteral injury. One patient suffered incision‐related complication that healed by debridement and dressing change. One patient developed subsidence of autologous iliac bone before discharge and achieved complete bony fusion after staying in bed and fixing it with a brace at 3 months follow‐up. All patients achieved bony fusion at final follow‐up.

Conclusion

Mis‐OLIF without anterior or posterior instrumentation and iliac graft is an effective and viable approach for the treatment of conservatively ineffective lumbar spondylodiscitis without spinal deformity or epidural abscess.

Decreasing thickness and remodeling of ligamentum flavum after oblique lumbar interbody fusion

PURPOSE

Ligamentum flavum is one of the structures that could compress the spinal canal. Few studies have reported atrophy of ligamentum flavum after spinal fusion. The purpose of this study was to demonstrate the reduction of ligamentum flavum size after oblique lumbar interbody fusion (OLIF) using magnetic resonance imaging (MRI).

METHOD

Seventeen patients who underwent OLIF without direct decompression were included. The MRI was obtained at the preoperative period, immediate postoperative period, and the follow-up period. Disc height (DH) was measured in plain radiograph. MRI measurements were spinal canal cross-sectional area (SCSA), ligamentum flavum thickness (LFT), ligamentum flavum area (LFA), and foraminal area (FA).

RESULTS

Mean age of the patients was 68.5 ± 10.8. Mean times between postoperative MRI and follow-up MRI were 20.2 ± 11.9 months. Mean disc height increased from 7.6 ± 1.6 to 11.6 ± 1.7 mm at an immediate postoperative period but decreased to 10.1 ± 1.6 mm during follow-up (p < 0.001). SCSA increased from 96.9 ± 54.9 to 136.0 ± 72.7 mm² and 171.4 ± 76.10 mm² during follow-up (p < 0.001). LFT decreased from 3.9 ± 1.2 to 3.2 ± 0.8 mm (17.9%) and further decreased to 2.9 ± 0.7 mm during follow-up (9.4%) (p < 0.001). LFA decreased from 97.4 ± 36.9 to 86.1 ± 36.9 mm2 (11.6%) and further decreased to 77.2 ± 32.5 mm² during follow-up (10.3%) (p = 0.001). FA increased from 69.2 ± 26.6 to 96.1 ± 23.0 mm² and increased to 112.9 ± 23.0 mm² during follow-up (p < 0.001).

CONCLUSION

OLIF could decompress the spinal canal and foraminal canal indirectly. Despite the diminishing disc height during the follow-up period, the spinal canal was further increased in size from the remodeling of the ligamentum flavum.

Variability in the size of the retroperitoneal oblique corridor: A magnetic resonance imaging-based analysis

Background:

A minimally invasive approach to the L2-S1 disc spaces through a single, left-sided, retroperitoneal oblique corridor has been previously described. However, the size of this corridor varies, limiting access to the disc space in certain patients. Here, the authors retrospectively reviewed lumbar spine magnetic resonance imaging (MRI) in 300 patients to better define the size and variability of the retroperitoneal oblique corridor.

Methods:

Lumbar spine MRI from 300 patients was reviewed. The size of the retroperitoneal oblique corridor from L2-S1 was measured. It was defined as the (1) distance between the medial aspect of the aorta and the lateral aspect of the psoas muscle from L2-L5 and (2) the distance between the midpoint of the L5-S1 disc and the medial aspect of the nearest major vessel on the left at L5-S1. In addition, the rostral-caudal location of the iliac bifurcation was measured.

Results:

The size of the retroperitoneal oblique corridor at L2/3, L3/4, L4/5, and L5/S1 was, respectively, 17.3 ± 6.4 mm, 16.2 ± 6.3 mm, 14.8 ± 7.8 cm, and 13.0 ± 8.3 mm. The incidence of corridor size <1 cm at L2/3, L3/4, L4/5, and L5/S1 was 10.3%, 16.0%, 30.0%, and 39.3%, respectively. The iliac bifurcation was most commonly found behind the L4 vertebral body (n = 158, 52.67%) followed by the L4/5 disc space (n = 74, 24.67%).

Conclusion:

The size of the retroperitoneal oblique corridor diminishes in a rostral-caudal direction, often limiting access to the L4/5 and L5/S1 disc spaces.

Standalone oblique lateral interbody fusion vs. combined with percutaneous pedicle screw in spondylolisthesis

Background

To compare standalone oblique lateral interbody fusion (OLIF) vs. OLIF combined with posterior bilateral percutaneous pedicle screw fixation (OLIF combined) for the treatment of lumbar spondylolisthesis.

Methods

This was a retrospective study of patients who underwent standalone OLIF or combined OLIF between 07/2014 and 08/2017 at two hospitals in China. Direct decompressions were not performed. Visual analog scale (VAS), Oswestry Disability Index (ODI), satisfaction rate, anterior/posterior disc heights (DH), foraminal height (FH), foraminal width (FW), cage subsidence, cage retropulsion, fusion rate, and complications were analyzed. All imaging examinations were read independently by two physicians and the mean measurements were used for analysis.

Results

A total of 73 patients were included: 32 with standalone OLIF and 41 with combined OLIF. The total complication rate was 25.0% with standalone OLIF and 26.8% with combined OLIF. There were no differences in VAS and ODI scores by 2 years of follow-up, but the scores were better with standalone OLIF at 1 week and 3 months (P < 0.05). PDH and FW was smaller in the combined OLIF group compared with the standalone OLIF group before and after surgery (all P < 0.05). There were significant differences in FH before surgery and at 1 week and 3 months between the two groups (all P < 0.05), but the difference disappeared by 2 years (P = 0.111). Cage subsidence occurred in 7.3% (3/41) and 7.3% (3/41) of the patients at 3 and 24 months, respectively, in the combined OLIF group, compared with 6.3% (2/32) and 15.6% (5/32), respectively, in the standalone OLIF group at the same time points (P = 0.287). There was no cage retropulsion in both groups at 2 years. The fusion rate was 85.4%(35/41) in the combined OLIF group and 84.4% (27/32) in the standalone OLIF group at 3 months(P = 0.669). At 24 months, the fusion rate was 100.0% in the combined OLIF group and 93.8% (30/32) in the standalone OLIF group (P = 0.066).

Conclusion

Standalone OLIF may achieve equivalent clinical and radiological outcomes than OLIF combined with fixation for spondylolisthesis. The rate of complications was similar between the two groups. Patients who are osteoporotic might be better undergoing combined rather than standalone OLIF. The possibilty of proof lies within a future prospective study, preferably an RCT.

[Minimally invasive lateral lumbar interbody fusion significantly improves the sagittal balance for adult degenerative scoliosis]

Objectives: To evaluate the effect of minimally invasive lateral lumbar interbody fusion (LLIF/OLIF) on the sagittal balance of adult degenerative scoliosis. Methods: From January 2014 to June 2017, a total of 23 patients with degenerative scoliosis underwent staged minimally invasive surgery in Shanghai Ruijin Hospital. All patients were implanted with LLIF or OLIF cage from the lateral approach first, and was followed by the posterior percutaneous pedicle screw fixation or pedicle screw fixation via Wiltse approach. If the sagittal deformity correction was not satisfactory after the first surgery, a posterior osteotomy can be performed during the second stage operation. A biplanar X-ray of the whole spine was taken with the EOS imaging system before and after surgery. The EOS software was used to measure and evaluate the patient's sagittal balance parameters including pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), the sagittal vertical axis (SVA) and the coronal Cobb angle. The visual analogue scale (VAS) score for low back pain, the Oswestry Disability Index (ODI) score were evaluated before and after surgery. Paired t test or repeated measures ANOVA was used to compare the data before and after surgery. Results: There were 6 males and 17 females with a mean age of (72±4) years (62-79 years). Nine patients were treated with LLIF and 14 patients with OLIF. Sixteen cases were implanted with three cages, five with two cages and two with four cages. The mean follow-up period was 24.2 months (15-42 months). After the first operation, the Cobb angle of the patient was significantly improved (18°±7° vs 33°±8°, t=13.2, P<0.01). All the parameters for sagittal balance, including PI-LL (20°±8° vs 31°±8(o)), SVA ((5.3±2.0) cm vs (8.2±3.5) cm), PT (16°±6° vs 23°±4°) were all significantly improved as well (t=6.8, 4.5, 9.0, ALL P<0.01). At the last follow-up, the VAS score of low back pain (3.4±1.1 vs 6.3±1.0) and ODI scores (27.3%±3.0% vs 47.1%±5.9%) were also significantly improved (t=11.3, 17.8, both P<0.01). No major complications occurred in this group. Conclusions: Minimally invasive LLIF/OLIF can significantly improve the coronal and sagittal balance of adult degenerative scoliosis. Staged minimally invasive surgery can significantly alleviate pain and improve function in these patients.

Quantitative analysis of paraspinal muscle atrophy after oblique lateral interbody fusion alone vs. combined with percutaneous pedicle screw fixation in patients with spondylolisthesis

BACKGROUND

There is no available literature for comparison on muscle atrophy between the "stand-alone" oblique lateral interbody fusion (OLIF) and regular OLIF (i.e., combined with percutaneous pedicle screws fixation (PPSF) in patients with spondylolisthesis). This study aimed to identify changes in back muscle atrophy between the two surgeries.

METHODS

This was a retrospective cohort study of patients who underwent OLIF or OLIF+PPSF at Beijing Jishuitan Hospital and Shanghai ChangZheng Hospital between 07/2014 and 10/2017. Computed tomography (CT) was used to measure functional cross-sectional area (FCSA) and fat infiltration percentage (FIP) of the multifidus and erector spinae before and 24 months after surgery.

RESULT

There were no differences in FCSA and FIP between OLIF (n = 32) and OLIF+PPSF (n = 41) groups before surgery. In the OLIF group, the multifidus and erector spinae FCSA and FIP did not change at 24 months (FCSA: multifidus: from 8.59 ± 1.76 to 9.39 ± 1.74 cm², P = 0.072; erector spinae: from 13.32 ± 1.59 to 13.55 ± 1.31 cm², P = 0.533) (FIP: multifidus: from 15.91 ± 5.30% to 14.38 ± 3.21%, P = 0.721; erector spinae: from 11.63 ± 3.05% to 11.22 ± 3.12%, P = 0.578). In the OLIF+PPSF group, the multifidus and erector spinae FCSA decreased (multifidus: from 7.72 ± 2.69 to 5.67 ± 1.71 cm², P < 0.001; erector spinae: from 12.60 ± 2.04 to 10.15 ± 1.82 cm², P < 0.001), while the FIP increased (multifidus: from 16.13 ± 7.01% to 49.38 ± 20.54%, P < 0.001; erector spinae: from 11.93 ± 3.22% to 22.60 ± 4.99%, P < 0.001). The differences of FCSA and FIP between the two groups at 24 months were significant (all P < 0.001). The patients in the standalone OLIF group had better VAS back pain, and JOA scores than the patients in the OLIF combined group (all P < 0.05) at 1 week and 3 months after surgery. There were two cases (4.9%) of adjacent segment degeneration in the OLIF combined group, while there was no case in the OLIF alone group.

CONCLUSIONS

Standalone OLIF had better clinical outcomes at 1 week and 3 months than OLIF+PPSF in patients with spondylolisthesis. OLIF may not result in paraspinal muscle atrophy at 24 months after surgery.

Clinical Effects of Oblique Lateral Interbody Fusion by Conventional Open versus Percutaneous Robot-Assisted Minimally Invasive Pedicle Screw Placement in Elderly Patients

OBJECTIVES

To compare the clinical outcomes of percutaneous robot-assisted minimally invasive pedicle screw insertion versus freehand fluoroscopy-assisted pedicle screw insertion using a traditional open technique in elderly patients undergoing an oblique lumbar interbody fusion (OLIF) procedure.

METHODS

Based on the inclusion and exclusion criteria, 80 patients with lumbar degenerative disease who attended the spinal surgery department of the Beijing Jishuitan Hospital between January 2017 and April 2018 were enrolled in the present study. Patients were randomized 1:1 to undergo percutaneous robot-assisted minimally invasive pedicle screw insertion (experimental group, n = 40) or freehand fluoroscopy-assisted pedicle screw insertion using a traditional open technique (control group, n = 40). Outcomes were accuracy of screw placement evaluated on postoperative CT using the modified Gertzbein and Robbins scale, operative time, blood loss, postoperative drainage, lower back and leg pain evaluated using a visual analogue scale (VAS), lumbar function evaluated using the Oswestry disability index (ODI), and complication rates.

RESULTS

A total of 344 vertebral pedicle screws were inserted: 170 screws in the experimental group, and 174 screws in the control group. Accurate screw placement was significantly higher in the experimental group (98.2% [167/170]) than in the control group (93.1% [162/174]). Clinical outcomes showed significant differences between the experimental and control groups in operative time, intraoperative blood loss, and postoperative VAS for lower back pain in the immediate postoperative period.

CONCLUSION

Robot-assisted pedicle screw insertion in OLIF is an effective strategy for the management of elderly patients with lumbar degenerative diseases.

[Guiding role of imaging evaluation in oblique lumbar interbody fusion]

OBJECTIVE

To summarize the guiding role of imaging evaluation of oblique lumbar interbody fusion (OLIF) in recent years.

METHODS

The reports of OLIF surgical imaging research at home and abroad in recent years were extensively reviewed and analyzed.

RESULTS

Preoperative imaging evaluation plays an important role in guiding the operation of OLIF, the placement of fusion Cage, the selection of indications, and the reduction of complications.

CONCLUSION

Detailed preoperative imaging evaluation can correctly estimate the indications of OLIF, and avoid the nerve, blood vessel, and muscle injuries.

Unilateral Versus Bilateral Percutaneous Pedicle Screw Fixation in Oblique Lumbar Interbody Fusion

OBJECTIVE

To compare clinical and radiologic outcomes of unilateral pedicle screw (UPS) and bilateral pedicle screw (BPS) fixations after single-level oblique lateral interbody fusion procedures.

METHODS

This retrospective study included 74 patients receiving single-level oblique lateral interbody fusion at L3-4 or L4-5 (June 2014 to June 2017). These patients were divided into BPS (n = 36) and UPS (n = 38) groups. Perioperative outcomes included operative time, blood loss, medical expenses, and complication rates. Radiologic outcomes included fusion rates and cage subsidence rates. Clinical outcomes included disability measured by the Oswestry Disability Index and pain measured by the visual analog scale.

RESULTS

The operative time was significantly shorter in the UPS group (76.2 ± 4.4 minutes) compared with the BPS group (127.0 ± 5.6 minutes, P < 0.001). There was a significant between-group difference in medical expenses ($11,044.8 ± $470.7 in UPS group vs. $15,018.4 ± $547.1 in BPS, P < 0.001). Blood loss and hospital stay did not differ between groups. Oswestry Disability Index and visual analog scale scores significantly decreased in both groups at different time points postoperatively compared with preoperatively. The UPS group had lower Oswestry Disability Index and visual analog scale scores than the BPS group at 7 days postoperatively, but no between-group difference was found after 1-month follow-up. Fusion rate was 86.8% in UPS group and 91.7% in BPS group (P > 0.05). Cage subsidence rates did not differ between groups.

CONCLUSIONS

Oblique lateral interbody fusion with UPS fixation is an effective and reliable option for single-level lumbar diseases. Compared with BPS fixation, it resulted in less blood loss, required less operative time, and had comparable effects on radiologic and clinical outcomes.

Delayed Ureter Stricture and Kidney Atrophy After Oblique Lumbar Interbody Fusion

BACKGROUND

Oblique lumbar interbody fusion (OLIF) is a surgical technique for lumbar interbody fusion that allows surgeons to use a large cage while preserving the spine muscles. The surgical corridor of OLIF is close to the ureter in the retroperitoneal space and therefore entails a potential for injury to this organ. Although there are some published cases of ureteral injury that were identified during OLIF, to our knowledge, there have been no reports about delayed ureteral strictures and kidney atrophy after OLIF. We report a case of ureter stricture and ipsilateral kidney atrophy that was incidentally identified a few months postoperatively without signs of ureter injury during the operation.

CASE DESCRIPTION

A 49-year-old woman presented with low back and right leg pain. On lumbar magnetic resonance imaging, a Meyerding grade 1 spondylolisthesis of L4 on L5 with L4 nerve root encroachment was confirmed. The patient underwent L4/L5 OLIF and was discharged on the 10th day after surgery with improved symptoms. Three months later, an abdominopelvic computed tomography performed for an unrelated condition showed left kidney atrophy. A retrograde ureteropyelogram confirmed a stricture near the operation site. A ureter stent was successfully inserted to overcome the stricture, but renal atrophy was not reversed.

CONCLUSIONS

Ureter injury may be observed with several months' delay after OLIF in patients without symptoms or laboratory abnormalities, even if no direct injury was noted during the procedure.

Anatomical Feasibility of Right Oblique Approach for L5-S1 Oblique Lumbar Interbody Fusion

BACKGROUND

We compared left and right vascular anatomy at the L5-S1 disc space and validated the anatomical feasibility of the right oblique approach for L5-S1 oblique lumbar interbody fusion.

METHODS

Axial T2-weighted magnetic resonance imaging studies at the L5-S1 disc level were used to study 274 subjects (164 women and 110 men; average age, 62.97 years). The distance from the center of the L5-S1 disc to the medial wall of the left or right vessel was measured. Using the vessel position, 3 groups were established: medial, middle, and lateral. To describe the morphological configuration, the vessel type and the presence of perivascular adipose tissue (PVAT) around the vessels were identified on both sides.

RESULTS

The vessels on the left L5-S1 disc space were located 12.47 mm from the midline and most subjects (209 subjects; 76.3%) were included in the medial or middle group. On the right side, the vessels were located more laterally (16.93 mm; P = 0.000) and most subjects (248 subjects; 90.5%) were in the middle or lateral group. On the left side, vessels were mostly veins (260 subjects; 94.9%) and 139 subjects (50.7%) had PVAT. On the right side, the vessels were mostly arteries (213 subjects; 77.7%) and 242 (88.3%) had PVAT.

CONCLUSIONS

The vessels on the right side of the L5-S1 disc were located more laterally, and most vessels on the right side were arteries accompanying PVAT, which might minimize vessel manipulation. These results indicate that the right side of the L5-S1 disc could provide feasible access for oblique lumbar interbody fusion at L5-S1.

Treatment of Adult Spinal Deformity with Sagittal Imbalance Using Oblique Lumbar Interbody Fusion: Can We Predict How Much Lordosis Correction Is Possible?

Study Design

Prospective, single-center study.

Purpose

The current trend of operative treatment for adult spinal deformity (ASD) is combined anterior-posterior staged surgery. When anterior surgery was first performed, oblique lumbar interbody fusion (OLIF) was employed; this method became increasing popular. This study aimed to determine the lordosis correction that can be achieved using OLIF and assess whether we can preoperatively predict the lordosis correction angle achieved using OLIF.

Overview of Literature

Many previous studies on OLIF have shown improved clinical and radiologic outcomes. With the increase in the popularity of OLIF, several surgeons have started using larger cages to attain greater lordosis correction. Moreover, some studies have reported complications of OLIF because of immoderate cage insertion. To our knowledge, this is the first prospective study that attempted to determine whether it is possible to predict the lordosis correction angle achieved with OLIF preoperatively, using fullextension lateral view (FELV).

Methods

Forty-six patients with ASD were enrolled. All the operations were performed by a single surgeon in two stages (first, anterior and second, posterior) with a 1-week interval. Radiological evaluation was performed by comparing the Cobb’s angle of the segmental and regional lordosis obtained using preoperative and postoperative simple radiography (including the FELV) and magnetic resonance imaging (MRI).

Results

Regional lordosis (L1–S1) in the whole-spine standing lateral radiograph was −3.03°; however, in the supine lateral MRI, it was 20.92°. The regional lordosis of whole-spine standing lateral and supine lateral (MRI) was significantly different. In the FELV, regional lordosis was 25.72° and that in the postoperative supine lateral (MRI) was 25.02°; these values were not significantly different.

Conclusions

Although OLIF offers many advantages, it alone plays a limited role in ASD treatment. Lordosis correction using OLIF as well as lordosis determined in the FELV was possible. Hence, our results suggest that FELV can help predict the lordosis correction angle preoperatively and thus aid the selection of the appropriate technique in the second staged operation.

Neuro-navigation assisted pre-psoas minimally invasive oblique lumbar interbody fusion (MI-OLIF): New roads and impediments

Introduction

Minimally invasive spine-oblique lumbar interbody fusion (MIS-OLIF) has emerged as a novel anterolateral, retroperitoneal, "pre-psoas" approach for lumbar interbody fusion for degenerative spinal instability, as well as for correction of deformity in patients without severe canal stenosis. In the last decade, the technique has gained popularity owing to several advantages like the minimal blood loss, minimal tissue dissection, preservation of posterior tension bands, better biomechanical strength, provision of mechanical stability to the lumbar spine, and a larger footprint of the implant, associated with it. It, thus, maximises load bearing on the cortical bone, and provides a better lordotic correction of the lumbar spine. The armamentarium is further boosted by the use of neuro-navigation and neuro-monitoring tools, thereby improving the surgical outcome.

Material and Methods

The clinical indications of MIS-OLIF and various fixation methods [lateral lumbar fixation (LLF) and percutaneous posterior pedicle fixation (PPF)] are discussed. The summary of the 15 patients on whom the technique was utilized, are discussed. The patients' demographics, clinical history and neurological examination data, pre- operative Oswestry disability index (ODI) and visual analogue scale (VAS) score, intraoperative surgical details and postoperative follow up clinical as well as radiological data were assessed. Complications, readmissions, length of stay, estimated blood loss, surgical time and surgical outcome were also recorded.

Results

11 cases had grade 1 spondylolisthesis and 4 had grade 2 spondylolisthesis. One patient had both grade I and II spondylolisthesis at different levels. 13 patients had improvement in mechanical back pain and neurogenic claudication. Two patients had improvement in back pain but one-sided limb radiculopathy persisted, which was treated conservatively. The mean pre-operative ODI score was 35 ± 6.1, which improved to 14.6 ± 4.1 at follow-up (range of follow-up: 1 to 10 months; mean 5.7 ± 3.3 months]. The mean pre-operative VAS score was 7 ± 0.7, which improved to 3.3 ± 0.4 at follow-up.

Conclusions

The MIS-OLIF technique at the L2-L5 levels has shown encouraging early surgical outcomes with a good fusion rate and rapid recovery. While utilizing the unfamiliar oblique trajectory, the use of navigation can guide the surgeon in real time and also help in reducing the radiation exposure.

Perioperative complications associated with minimally invasive surgery of oblique lumbar interbody fusions for degenerative lumbar diseases in 113 patients

OBJECTIVES

To describe perioperative complications occurring during oblique lumbar interbody fusion (OLIF) assisted by a retractor system for degenerative lumbar diseases.

PATIENTS AND METHODS

The perioperative complications in 113 cases series utilizing a minimally invasive approach were recorded and analyzed. One hundred thirteen patients who received OLIF for degenerative lumbar diseases between November 2014 and February 2017 at a single center were evaluated. The most frequent diagnosis was spondylolisthesis (59 cases, 52.2%), followed by lumbar instability (24 cases, 21.2%), adjacent segmental disease (12 cases, 10.6%), adult degenerative scoliosis (11 cases, 9.8%) and discogenic low back pain (7 cases, 6.2%). One hundred thirty-four levels were treated, 88.5% one-level, 4.4% two-level, and 7.1% three-level surgeries. The most fused level was L4-5 (94 levels, 70.2%), followed by L3-4 (31 levels, 23.1%), and L2-3 (9 levels, 6.7%).

RESULTS

All perioperative complications only included adverse events related to the OLIF procedure. The most observed complications were donor-site pain (24 cases, 21.2%), followed by vertebral endplate fracture (15 cases, 13.3%), thigh numbness/pain (12 cases, 10.6%), psoas/quadriceps weakness (5 cases, 4.4%), sympathetic nerve injury (2 case, 1.8%), paralytic ileus (one case, 0.9%), segmental artery injury (one case, 0.9%), intervertebral infection (one, 0.9%), and contralateral femoral nerve palsy (one, 0.9%). All complications, including postoperative ipsilateral or contralateral thigh paresthesia, pain, and psoas/quadriceps weakness, were observed when operating at L4-L5. The incidence of complications excluding donor-site pain was 24.8% (28/113 cases). The patients with donor-site pain, thigh numbness/pain, psoas/quadriceps weakness, sympathetic nerve injury and paralytic ileus recovered within two months following surgery. The patient with intervertebral infection recovered at 3 months after surgery. One case of contralateral femoral nerve palsy recovered completely with no residual sensory or motor deficit at 6 months.

CONCLUSIONS

OLIF performed using a retractor system is a validated option to treat a wide spectrum of degenerative lumbar diseases with few perioperative complications and a quick recovery. Judicious use of this technique at the L4/5 level is recommended. Close attention to detail during the procedure can minimize complications that may be associated with the learning curve.

Precautions for Combined Anterior and Posterior Long-Level Fusion for Adult Spinal Deformity: Perioperative Surgical Complications Related to the Anterior Procedure (Oblique Lumbar Interbody Fusion)

Study Design

Retrospective, single-center study.

Purpose

We aimed to determine the perioperative complications of oblique lumbar interbody fusion (OLIF) as a first-stage procedure in combined anterior and posterior operation for adult spinal deformity (ASD) along with sagittal imbalance. Specifically, we aimed to identify the radiological and clinical types of perioperative surgical complications and the factors affecting these complications.

Overview of Literature

OLIF has recently gained popularity, and there are several reports of good outcomes and only a few of complications with OLIF; however, a few studies have focused on the perioperative surgical complications of ASD along with sagittal imbalance.

Methods

The perioperative period was a 1-week interval between the anterior and posterior procedures. All patients underwent simple radiography and magnetic resonance imaging preoperatively and postoperatively. Cage placement was evaluated for displacement (i.e., subsidence and migration) and vertebral body fracture. Clinical patient complaints were evaluated perioperatively. Student t-test was used for data analysis.

Results

A total of 46 patients were included, totaling 138 fusion segments. A week after OLIF, 14 patients/33 segments (30.4%/23.9%) demonstrated endplate injury-associated cage placement change. Subsidence was the most common cage placement-related complication. As compared with patients without endplate injury, those with endplate injuries showed significantly larger correction angles and a higher proportion of them had larger height cages than the disk height in the full-extension lateral view. Although 32.6% of the patients experienced perioperative clinical complications, they were relatively minor and transient. The most common complication was severe postoperative pain (Visual Analog Scale score of >7), and hip flexor weakness spontaneously resolved within 1 week.

Conclusions

OLIF yielded more than expected endplate injuries from treatment modalities for ASD along with sagittal imbalance. Therefore, surgeons should be cautious about endplate injury during OLIF procedures. It is difficult to accomplish lordosis correction via OLIF alone; therefore, surgeons should not attempt this impractical correction goal and insert an immoderate cage.

How I do it? Oblique lumbar interbody fusion at L5S1(OLIF51)

BACKGROUND

OLIF51 retains the advantages of traditional ALIF procedure with good fusion rates and improvement in radiographic parameters and reduces its drawbacks. It has the added advantage of being a minimal access technique.

METHODS

Preoperative analysis of the vascular anatomy using CT angiography is mandatory. OLIF51 is done in right lateral position using specialized retractor blades and Thompson retractor system. The procedure is similar to OLIF at other levels except for the differences described here. The instruments are specialized for OLIF at L5S1.

CONCLUSION

OLIF51 provides an excellent alternative to traditional ALIF.

Spondylolisthesis with Uncommon Congenital Deformity of L4-L5 Vertebral Fusion Treated by Oblique Lumbar Interbody Fusion

BACKGROUND

Diagnosis and management of congenital anomalies of the spine can be a challenge because of their complex presentations. We present an uncommon case of congenital deformity of the spine with L4-L5 vertebral fusion, mimicking a single vertebra, and L3 spondylolisthesis treated by oblique lumbar interbody fusion (OLIF).

CASE DESCRIPTION

A 69-year-old woman presented with increasing lower back pain radiating to the left leg, with aggravation of symptoms for the past 6 months, causing difficulty in walking. She also complained of paresthesia along the L3-L5 dermatomes in both legs, with more prominence on the left side. Imaging revealed fusion deformity of the L4-L5 vertebrae, as well as degenerative spondylolisthesis at the L3-L4 level. After treatment with OLIF, the patient had an uneventful recovery period. Comparisons were made between the preoperative and 6-month follow-up visual analog scale and the Oswestry Disability Index scores. The patient showed significant improvement in the scores, as well as in her symptoms.

CONCLUSIONS

OLIF is a promising technique that can be applied in the management of degenerative disk diseases and also for deformities that may be formidable to treat by adopting the traditional posterior approach.

Safety Analysis of Two Anterior Lateral Lumbar Interbody Fusions at the Initial Stage of Learning Curve

OBJECTIVE

Until now, there were few studies on the safety analysis of oblique lumbar interbody fusion (OLIF) and extreme lateral interbody fusion (XLIF) in the initial stage of learning curve. The purpose of this study was to find out the safety differences between the 2 minimally invasive fusion methods in the initial stage of learning curve and to provide reference for beginners.

METHODS

We retrospectively collected the first 30 cases of lumbar degenerative disease with OLIF or XLIF in our center since June 2014. Patients were divided into group OLIF and group XLIF according to different operative methods. The clinical efficacy and complications of the 2 groups were compared. A P <0.05 was statistically significant.

RESULTS

Group XLIF were aged 37-74 years (mean 58.4 years) and group OLIF were aged 39-71 years (mean 56.1 years). There were no significant differences between the 2 groups in age, sex, operation time, intraoperative bleeding volume, operation segment, and follow-up time. The incidence of complications in group XLIF was significantly lower than that in group OLIF (10% vs. 33.3%; P = 0.028).

CONCLUSIONS

OLIF has a higher risk of neurovascular injury in the initial stage of learning. By contrast, the XLIF approach is simple and the incidence of complications is relatively low. Therefore, we believed that XLIF is more acceptable in the initial stage of anterolateral lumbar interbody fusion.

Vertebral Body Rotation in Patients with Lumbar Degenerative Scoliosis: Surgical Implication for Oblique Lumbar Interbody Fusion

BACKGROUND

To investigate changes of oblique corridor in patients with lumbar degenerative scoliosis and determine proper working angle with respect to the direction of vertebral axial rotation during the oblique lumbar interbody fusion procedure.

METHODS

The distance of oblique corridor and the rotational angle of the left or right apex group were measured on axial T2 magnetic resonance images and then compared with those of the propensity score-matched control group.

RESULTS

Fifty-five patients of the left apex group and 57 patients of the right apex group were compared with the equal number of patients of the propensity score-matched control group. The distance of oblique corridor in the left apex group was shorter than that in the control group at the levels of L1-2 and L2-3. In contrast, the distance of oblique corridor in the right apex group was longer than that of the control group at the level of L2-3. Patients of the left apex group showed the vertebral body rotating to the left side from L1-2 to L5-S1, whereas in the right apex group, the vertebral body rotated to the right side at the levels of L1-2, L2-3, and L3-4.

CONCLUSIONS

In the left apex group, the oblique corridor was decreased from psoas overlap, and coupled axial rotation to the left side might increase the risk of contralateral nerve root injury during orthogonally working. Thus, surgeons should pay attention to the state of coupled vertebral axial rotation of lumbar degenerative scoliosis for the oblique lumbar interbody fusion procedure.

Relation of lumbar sympathetic chain to the open corridor of retroperitoneal oblique approach to lumbar spine: an MRI study

BACKGROUND

Retroperitoneal oblique approach to lumbar spine used surgical corridor between psoas muscle and aorta for exposure to anterior part of lumbar spine. Lumbar sympathetic chain (LSC) runs in the corridor to make it a structure at risk of injury.

RESEARCH QUESTION

Does LSC relationship with surgical corridor for minimally invasive retroperitoneal anterolateral oblique approach change in different intervertebral disc level?

METHODS

Left LSC was identified in axial magnetic resonance imaging images at L2-3, L3-4 and L4-5 intervertebral disc levels of 144 patients. Distances between LSC and left psoas muscle and aorta were recorded.

RESULTS

Mean age of the patients was 62.3 years. LSC was identifiable in 90.9% of levels. Distance between LSC and psoas muscle at L2-3, L3-4 and L4-5 was 4.0 mm, 4.7 mm and 5.2 mm. Statistical difference was found between L2-3 and L4-5 level (p = 0.006). Distance between LSC and aorta at each level was 12.4 mm, 12.3 mm and 10.6 mm without statistical difference. In non-scoliosis group distance between LSC and psoas muscle at each level was 3.1 mm, 3.3 mm and 4.0 mm. Statistical difference was found between L2-3 and L4-5 level (p = 0.012) and between L3-4 and L4-5 level (p = 0.041). Distance between LSC and aorta at each level was 11.9 mm, 11.4 mm and 10.2 mm. Statistical difference was found between L2-3 and L4-5 disc level (p = 0.039).

CONCLUSION

LSC moves away from psoas muscle and becomes closer to aorta in L4-5 disc level. These slides can be retrieved under Electronic Supplementary Material.

Microscopic Anterior Neural Decompression Combined with Oblique Lumbar Interbody Fusion-A Technical Note

BACKGROUND

Minimally invasive oblique lumbar interbody fusion (OLIF) techniques generally rely on deformity correction to achieve indirect neural decompression. However, indirect neural decompression will not always be sufficient. Thus, a second procedure, such as posterior direct decompression, will be added for full decompression, increasing the surgical morbidity and healthcare costs. We have described a technique of direct anterior microscopic neural decompression combined with OLIF.

METHODS

We report our surgical technique of anterior lumbar neural microscopic decompression with OLIF with patients in the lateral position. We also report the cases of 3 patients treated from March 2018 to June 2018.

RESULTS

Three patients underwent anterior microscopic neural decompression combined with OLIF in the lateral position. All 3 patients achieved clinically and radiologically significant neural decompression and deformity correction. No perioperative complications developed.

CONCLUSION

Direct anterior microscopic neural decompression is feasible and safe in selected patients undergoing OLIF.

Endoscope-assisted oblique lumbar interbody fusion for the treatment of cauda equina syndrome: a technical note

OBJECTIVE

The goal of this paper was to describe how endoscope-assisted oblique lumbar interbody fusion (OLIF) could remove huge lumbar disc herniation (HLDH) manifested with cauda equina syndrome (CES).

METHODS

In this study, the authors made an attempt to treat CES with a direct endoscopic decompression through the OLIF corridor and performed OLIF in two patients with HLDH.

RESULTS

Two patients with HLDH were successfully treated using OLIF with spinal endoscopic discectomy. We achieved direct ventral decompression by removal of herniated disc fragments located beyond the posterior longitudinal ligament (PLL). All preoperative symptoms in two patients improved postoperatively.

CONCLUSIONS

Endoscope-assisted oblique lumbar interbody fusion (OLIF) could successfully achieve neural decompression without additional posterior decompression in CES and could be used as an alternative treatment in well selected cases.

Oblique Lumbar Interbody Fusion: Technical Aspects, Operative Outcomes, and Complications

OBJECTIVE

Anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) are commonly used approaches for lumbar spine fusion surgery, each with their own unique advantages and disadvantages. ALIF requires mobilization of the great vessels and peritoneum, and dissection of the psoas muscle in the LLIF technique is associated with postoperative neurologic complications in the proximal lower limb. The anterior-to-psoas (ATP) or oblique lumbar interbody fusion (OLIF) technique is the proposed solution to accessing the L1-L5 levels without the issues encountered with ALIF and LLIF. In this review, the technical nuances, operative outcomes, and complications with the ATP/OLIF technique in the current literature are summarized.

METHODS

A systematic search of the literature was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Data collected included operative time, blood loss, postoperative hospital stay, and complications, which were then pooled together.

RESULTS

From the 16 studies selected, the mean blood loss was 109.9 mL, average operating time was 95.2 minutes, and mean postoperative hospital stay was 6.3 days. Fusion was achieved in 93% of levels operated. Incidence of intraoperative and postoperative complications was 1.5% and 9.9%, respectively. Transient thigh pain and/or numbness and hip flexion weakness occurred in 3.0% and 1.2% of patients, respectively.

CONCLUSIONS

Early results on the ATP/OLIF technique are promising and warrant further investigation with well-designed prospective randomized studies to provide high-level evidence of the potential advantages over the ALIF and LLIF approaches.

Oblique Lumbar Interbody Fusion for Revision of Non-union Following Prior Posterior Surgery: A Case Report

We report the case of a 75-year-old lady who presented with a L2-3 non-union 18 months following a L2-3 and L3-4 posterior decompression and transforaminal lumbar interbody fusion. Halo of the L2 pedicle screws on imaging was consistent with a non-union at the L2-3 level. An anterior lumbar interbody fusion (ALIF) approach was originally considered. However, due to the high lumbar approach and patient habitus [body mass index (BMI) > 35], a decision was made to approach the L2-3 level using an oblique technique. This involved dissection anterior to the psoas muscle to access the L2-3 disc space. The psoas, kidney and retroperitoneum were retracted using a Synframe for the oblique trajectory. Removal of the prior trans-foraminal lumbar interbody fusion cage was performed via the oblique approach and insertion of a revised implant. The operation was completed successfully with no perioperative complications noted. Length of stay was 3 days, with the patient achieving rapid pain relief. In the present report, we report the first case using an oblique lumbar interbody fusion (OLIF) approach for revision of a prior posterior fusion non-union at the L2,3 level. The OLIF technique is feasible for revision of a non-union of upper lumbar levels, with satisfactory fusion achieved with acceptable feasibility.