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

A novel surgical approach using the "lateral corridor" for minimally invasive oblique lumbar interbody fusion at L5-S1: a clinical series and technical note

PURPOSE

The minimally invasive oblique lumbar interbody fusion (MI-OLIF) L5-S1 was introduced to overcome the limitations of conventional fusion techniques, however, MI-OLIF is not possible using the standard method due to vascular structures in some cases. We aimed to introduce the "lateral corridor" and report the details of the surgical technique with a clinical case series.

METHODS

We utilized the lateral access route of the left common iliac vein and named it the "lateral corridor", to distinguish the technique from the standard technique (central corridor). The type and frequency of branch vessels that required additional manipulations were reviewed, and the frequency of intraoperative vascular injury was investigated.

RESULTS

Among the 107 patients who underwent MI-OLIF L5-S1, 26 patients (24.3%) who received the "lateral corridor" technique were included. Branch vessel ligation was required in 42.3% of the patients. The types of branch vessels that required ligation were seven cases (26.9%) of the iliolumbar vein (ILV) and six cases (23.1%) of ascending lumbar vein (ALV). The ILV and ALV were ligated in two cases. None of the patients developed intraoperative vascular injuries.

CONCLUSION

We introduced the "lateral corridor" as an alternative approach for MI-OLIF L5-S1, implemented it in 24.3% of the patient cohort, and reported favorable outcomes devoid of vascular complications. The "lateral corridor" necessitated ligation of the ILV or ALV in 42.3% of cases. The "lateral corridor" approach appears to be a promising surgical technique, offering feasibility even in instances where the vascular anatomy precludes the employment of the conventional approach.

L5 Nerve Root Radiculopathy as a Rare Complication Following Oblique Lateral Interbody Fusion at L5/S1 Combined With Posterior Fixation via Percutaneous Pedicle Screws for Adult Spinal Deformity

Oblique lateral interbody fusion (OLIF) is an established and less invasive surgical approach for patients with adult spinal deformities. This method can also be applied to the L5/S1 region (termed "OLIF51"); however, reports on L5 nerve root radiculopathy as a rare complication of OLIF51 are limited. Here, we present the case of a 77-year-old woman with progressive adult spinal deformity who was followed up after an initial OLIF for the L3/4 and L4/5 levels. An additional operation was performed to resolve ambulation difficulty and back pain related to adult spinal deformity. Circumferential fixation was performed over two sessions. Initially, OLIF51 was performed concurrently with OLIF for L1/2 and L2/3. Eight days later, posterior fixation surgery from T10 to the ilium via percutaneous pedicle screws was performed. Two days after the second operation, the patient started complaining of left L5 nerve root radiculopathy, for which medication and rehabilitation were both ineffective. Retrospectively, we identified that the left L5/S1 foramen narrowed after the lordotic correction by OLIF51 and posterior fixation. Additionally, posterior facetectomy for L5/S1 was performed, and the left L5 nerve root radiculopathy was resolved. L5 nerve root radiculopathy can develop as a rare complication of OLIF51. Neurosurgeons should be aware of this rare complication related to OLIF51.

How to Choose Surgical Corridor in Left Oblique Approach Lumbar Interbody Fusion at the L5-S1 Segment: A Prospective Cohort Study

OBJECTIVE

There are 2 surgical corridors to L5-S1 lumbar interbody fusion via the left oblique approach: anterior to psoas-oblique lateral interbody fusion (ATP-OLIF) and oblique-anterior lumbar interbody fusion (O-ALIF). The aim of this study was to evaluate criteria to guide the selection of surgical corridors for L5-S1 lumbar interbody fusion via the left oblique approach.

METHODS

According to the structure of L5-S1 segment left common iliac vein (LCIV) in axial magnetic resonance image, the LCIV was divided into 6 types. O-ALIF was performed for type I and type II. ATP-OLIF was performed for type A and type B. For sexually active men, ATP-OLIF was chosen. Between April 2020 and April 2022, 22 patients were assigned to ATP-OLIF or O-ALIF based on the type of LCIV. Clinical outcomes and radiographic outcomes were assessed.

RESULTS

There were 11 cases in O-ALIF group (type I, n = 10; type II, n = 1) and 11 cases in ATP-OLIF group (type A, n = 8; type B, n = 3). No differences were observed in clinical outcomes (Oswestry Disability Index, VAS, and complication rate); radiographic outcomes (mean disk height and segmental lordosis angle); length of hospital stay; operation time; and blood loss. No vascular injury occurred in either group.

CONCLUSIONS

This may be an appropriate criterion to guide the selection of surgical corridor for L5-S1 lumbar interbody fusion through the left oblique approach. O-ALIF was performed for type I and type II. ATP-OLIF was performed for type A and type B. For sexually active men, ATP-OLIF was chosen. According to this standard, the operation can be performed safely and with good clinical results.

Endoscopic anterior to psoas lumbar interbody fusion: indications, techniques, and clinical outcomes

PURPOSE

The retrospective study aimed to report the surgical technique and clinic-radiological outcomes of endoscopic anterior to psoas interbody lumbar fusion through the retroperitoneal approach with direct and indirect decompression.

METHODS

We retrospectively analyzed the results of clinical parameters of patients who underwent endoscopic anterior to psoas interbody lumbar fusion between June 2013 and June 2022. Clinical outcomes were evaluated by the visual analog scale (VAS) and Oswestry Disability Index (ODI) scores. The radiological outcomes were measured and statistically compared in disc height index (DHI), whole lumbar lordosis (WLL), pelvic Incidence (PI), pelvic tilt (PT), Segmental lordosis (SL), the sagittal vertical axis (SVA).

RESULTS

A total of 35 patients were selected for the procedure ranging in age from 51 to 84 years with 17.83 ± 8.85 months follow-up. The mean operation time in lateral position for one level was 162.96 ± 35.76 min (n = 24), and 207.73 ± 66.60 min for two-level fusion. The mean endoscopic time was 32.83 ± 17.71 min per level, with a total estimated blood loss of 230.57 ± 187.22 cc. The mean postoperative VAS back, leg pain score and ODI improved significantly compared to the preoperative values; Radiological data showed significant change in WLL, SL, DHI, PI, PT, and SS; however, there is no significant difference in SVA postoperatively. Subgroup analysis for the radiographic data showed 50 mm length cage has significantly improved for the DHI, SS and SVA compare to 40 mm length cage. The subgroup analysis results showed that hypertensive patients had significantly higher proportion in the incomplete fusion group compare to complete fusion group at one-year follow-up.

OUTCOMES

The endoscopic anterior to psoas interbody lumbar fusion achieves satisfactory indirect and direct decompression. This convergent technique presents an effective choice for treating lumbar instability associated with disc herniations and foraminal stenosis, thus complementing the indications for oblique lumbar interbody fusion.

The anatomical feasibility of anterior intra- and extra-bifurcation approaches to L5-S1: an anatomic study based on lumbar MRI

BACKGROUND CONTEXT

The anterior approach at L5-S1 has many advantages, however, vascular complications are challenging for spinal surgeons who may not be familiar with the variability of vascular anatomy. There are three different anterior approaches (intra-bifurcation approach and extra-bifurcation: left-, and right-sided prepsoas approaches) described in previous studies to respond to the variability of anterior vascular anatomy for reduction in vascular injury, while no guidance for the choice of approach preoperatively.

PURPOSE

To analyze the anatomical feasibility of three anterior approaches to access the L5-S1 disc space according to a practical framework.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

Lumbar magnetic resonance imaging (MRI) from patients who visited our outpatient clinic were reviewed, with 150 cases meeting the inclusion criteria.

OUTCOME MEASURES

The following radiographic parameters were measured on axial T2-weighted MRI at the lower endplate of L5 and the upper endplate of S1: width of the vascular corridor, position of the left and right common iliac vein (CIV), and presence of perivascular adipose tissue (PAT). Moreover, we designed a safe line to evaluate the feasibility of left- and right-sided prepsoas approaches. Cases of lumbosacral transitional vertebrae were identified.

METHODS

The feasibility of the intra-bifurcation approach was determined by the width of the vascular corridor, presence of PAT, and the position of the CIV. The feasibility of the prepsoas approach was determined by the relative position of the CIV to the safe line, presence of PAT, and the intersection point of the CIV and vertebral body.

RESULTS

Sixty-eight percent, 64.7%, and 75.3% cases allowed the intra-bifurcation, left-, and right-sided prepsoas approach to L5-S1, respectively. The cases in this study had at least one of three anterior approaches to access L5-S1 disc space, and 74% of cases had more than one anatomical feasibility of anterior approach. The right-sided prepsoas approach was feasible in the majority of cases because of the vertical course of the right CIV with a significantly higher proportion of presence of PAT. Patients with lumbosacral transitional vertebrae (24 cases) may prefer the prepsoas approaches, and only six cases (25.0%) were determined to be feasible for the intra-bifurcation approach.

CONCLUSIONS

Our study proposes a practical framework to determine whether the three different anterior approaches are feasible access at L5-S1. According to the framework, all cases had the anatomical feasibility of using an anterior approach to access L5-S1, and three-fourths of cases had a replaceable anterior approach when encountering intraoperative difficulties.

Characterizing and Improving Nomenclature for Reporting Lumbar Interbody Fusion Techniques

OBJECTIVE

Lumbar interbody fusion (LIF) techniques have seen impressive innovation in recent years, leading to an expansion of the LIF lexicon. This study systematically analyzes LIF nomenclature in contemporary literature and proposes a standardized classification system for reporting LIF terminology.

METHODS

A search query was conducted through the PubMed database using "lumbar fusion OR lumbar interbody fusion." A total of 1455 articles were identified, and 605 references to LIF were recorded. Following a systematic review of the terminology, we developed a LIF reporting guidelines that capture the existing LIF nomenclature while avoiding redundant or ambiguous terminology.

RESULTS

The most referenced anatomical approaches were transforaminal (43.0%), followed by posterior (25.0%), lateral (19.7%), and anterior (10.9%). Overall, there were 72 unique ways to describe LIF. Unique prefixes were recorded by approach (posterior: 26; lateral: 13; anterior: 3). Forty unique prefixes/suffixes overlapped in their usage. "MI" (14.4%), "MIS" (38.1%), and "MISS" (0.6%) all referenced a minimally invasive approach. "O" (12.5%), "CO" (1.3%), and "TO" (1.3%) all described open techniques. "Endo" (0.6%), "Endoscopic-assisted" (1.3%), and "PE" (1.9%) all referenced endoscopic-assisted procedures.

CONCLUSIONS

The current LIF nomenclature contains many unique LIF terms that were found to be inconsistently defined, redundant, or ambiguous. We propose the standardization of a 4-part naming system which highlights the crucial parts of LIF: (1) intraoperative repositioning, (2) patient position, (3) anatomical approach, and (4) orientation of the surgical corridor to the psoas muscles.

Can oblique lateral interbody fusion (OLIF) create more lumbosacral lordosis in lumbar spine surgery than minimally invasive transforaminal interbody fusion (MIS-TLIF)?

Objective

To compare the differences in the correction effect for lumbosacral lordosis and clinical outcomes between OLIF with/without posterior pedicle screw fixation (PSF) and MIS-TLIF through a retrospective cohort study.

Method

There were 98 consecutive patients originally enrolled for the study, but 15 patients were excluded due to intraoperative endplate injury or osteotomy performed for severe spinal deformity. Thus, 83 patients included in this study (36 males and 47 females, mean age 65.8 years) underwent single to three-segment OLIF (including OLIF + PSF and OLIF Standalone) or MIS-TLIF surgery from 2016 to 2018. The operation time, bleeding and blood transfusion, fusion rate, complication, pre-and postoperative visual analogue scale (VAS), Oswestry Disability Index (ODI) were evaluated. In addition, radiological parameters including lumbosacral lordosis (LL), fused segment lordosis (FSL), anterior disc height (ADH) and posterior disc height (PDH) were measured. The clinical outcomes, LL, FSL, ADH and PDH restored and were compared between the OLIF group, OLIF subgroups and MIS-TLIF group.

Results

The average operation time and intraoperative bleeding were significantly less in the OLIF group than in the MIS-TLIF group (163 ± 68 vs. 233 ± 79 min, 116 ± 148 vs. 434 ± 201 ml, P < 0.001). There was no statistically significant difference between the OLIF group and the MIS-TLIF group in VAS and ODI improvements, fusion rate, complication, LL and FSL correction (P > 0.05). The ADH and PDH increases in the OLIF group were more than that in MIS-TLIF group (P < 0.001). The correction of LL was significantly more in the OLIF + PSF group than in the MIS-TLIF group (9.9 ± 11.1 vs. 4.2 ± 6.1deg, P = 0.034).

Conclusion

OLIF and MIS-TLIF are both safe and effective procedures, capable of restoring lumbosacral lordosis and disc height partly. Combined with PSF, OLIF can achieve a better correction effect of lumbosacral lordosis than MIS-TLIF.

Radiographic comparison of L5-S1 lateral anterior lumbar interbody fusion cage subsidence and displacement by fixation strategy: anterior plate versus integrated screws

OBJECTIVE

The aim of this study was to radiographically compare cage subsidence and displacement between L5-S1 lateral anterior lumbar interbody fusion (ALIF) cages secured with an anterior buttress plate and cages secured with integrated screws.

METHODS

Consecutive patients who underwent L5-S1 lateral ALIF with supplemental posterior fixation by a single surgeon from June 2016 to January 2021 were reviewed. Radiographs were analyzed and compared between the two groups based on the type of fixation used to secure the L5-S1 lateral ALIF cage: 1) anterior buttress plate or 2) integrated screws. The following measurements at L5-S1 were analyzed on radiographs obtained preoperatively, before discharge, and at latest follow-up: 1) anterior disc height, 2) posterior disc height, and 3) segmental lordosis. Cage subsidence and anterior cage displacement were determined radiographically.

RESULTS

One hundred thirty-nine patients (mean age 60.0 ± 14.3 years) were included for analysis. Sixty-eight patients were treated with an anterior buttress plate (mean follow-up 12 ± 5 months), and 71 were treated with integrated screws (mean follow-up 9 ± 3 months). Mean age, sex distribution, preoperative L5-S1 lordosis, preoperative L5-S1 anterior disc height, and preoperative L5-S1 posterior disc height were statistically similar between the two groups. After surgery, the segmental L5-S1 lordosis and L5-S1 anterior disc heights significantly improved for both groups, and each respective measurement was similar between the groups at final follow-up. Posterior disc heights significantly increased after surgery with integrated screws but not with the anterior buttress plate. As such, posterior disc heights were significantly greater at final follow-up for integrated screws. Compared with patients who received integrated screws, significantly more patients who received the anterior buttress plate had cage subsidence cranially through the L5 endplate (20.6% vs 2.8%, p < 0.01), cage subsidence caudally through the S1 endplate (27.9% vs 0%, p < 0.01), and anterior cage displacement (22.1% vs 0%, p < 0.01).

CONCLUSIONS

In this radiographic analysis of 139 patients who underwent lateral L5-S1 ALIF supplemented by posterior fixation, L5-S1 cages secured with an anterior buttress plate demonstrated significantly higher rates of cage subsidence and anterior cage displacement compared with cages secured with integrated screws. While the more durable stability afforded by cages secured with integrated screws suggests that they may be a more viable fixation strategy for L5-S1 lateral ALIFs, there are multiple factors that can contribute to cage subsidence, and, thus, definitive presumption cannot be made that the findings of this study are directly related to the buttress plate.

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

Background

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

Methods

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

Results

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

Conclusions

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

Extreme lateral interbody fusion (XLIF) approach for L5-S1: Preliminary experience

Study Design

Technical report.

Objective

Evaluate technical feasibility of extreme lateral interbody fusion (XLIF) at the L5-S1 level and provide an elaborate description of the surgical technique.

Summary of Background Data

With the development of surgical techniques, the indications for oblique lumbar interbody fusion (OLIF) surgery have been broadened to the L5/S1 segment. However, this technique also has limitations. Different from OLIF, the L5/S1 segment used to be considered the main contraindication for XLIF. To date, no authors have reported the application of XLIF at the L5/S1 level.

Methods

Only patients whose preoperative lumbar MRI showed the position of the psoas major muscles and blood vessels at the L5/S1 level were similar to those seen at supra-L5 levels were seleted. By folding the operating table, the iliac crest was moved downward to expose the L5/S1 intervertebral space during the operation. The remaining surgical procedures were consistent with routine XLIF surgery.

Results

8 patients successfully underwent XLIF at the L5/S1 level. The L5/S1 disk spaces were always exposed sufficiently for disk preparation and cage insertion. The post operative radiographs showed a satisfactory L5/S1 reconstruction with good cage position. Only 1 patient (12.5%) felt thigh numbness, and the symptoms gradually resolved after surgery and were no longer present in a month. There were no cases of psoas hematoma, retrograde ejaculation or vascular injury. The postoperative VAS score showed that all the patients achieved satisfactory results.

Conclusions

XLIF at L5-S1 is feasible in strictly selected cases after thorough preoperative preparation and careful intraoperative procedures. However, we did not recommend XLIF as a routine surgical option at the L5/S1 level.

Single-position anterior and lateral lumbar fusion in the supine position: a novel technique for multi-level arthrodesis

OBJECTIVE

Anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) are common techniques that typically require staged procedures when performed in combination. Interest is emerging in single-position surgery to increase operative efficiency. We report a novel surgical technique, supine extended reach (SupER) lateral fusion, to perform ALIF and LLIF with the patient in a single supine position.

METHODS

A man in his fifties presented with degenerative levoscoliosis, spondylolisthesis, sagittal-plane deformity, and progressive low back pain. He was offered L3-S1 anterolateral fusion.

RESULTS

With the patient supine, a left abdominal paramedian incision was performed to gain anterior retroperitoneal access, and standard L5-S1 and L4-5 ALIFs were performed. The anterior incision was used for direct visualization, retraction, and bimanual dissection. A left lateral incision was then made to perform an L3-4 LLIF. The patient subsequently underwent a second-stage L3-S1 posterior percutaneous fixation. The patient tolerated the procedures well, without complications. Postoperative radiograph findings confirmed acceptable implant positioning. The patient was discharged home in stable condition and was doing well at follow-up.

CONCLUSION

This case description is the first report of the SupER technique, which allows incorporation of anterior and lateral fusion constructs at adjacent levels without changing patient positioning. Many surgeons believe the ALIF to be the most powerful technique for achieving lordosis, and this technique enables concomitant lateral access in a supine position. It can also be used as an alternative strategy when anterior access to the disc space is unobtainable. Further clinical investigation of this technique is warranted.

Utilization of lateral anterior lumbar interbody fusion for revision of failed prior TLIF: illustrative case

BACKGROUND

The use of the lateral decubitus approach for L5–S1 anterior lumbar interbody fusion (LALIF) is a recent advancement capable of facilitating single-position surgery, revision operations, and anterior column reconstruction. To the authors’ knowledge, this is the first description of the use of LALIF at L5–S1 for failed prior transforaminal lumbar interbody fusion (TLIF) and anterior column reconstruction. Using an illustrative case, the authors discuss their experience using LALIF at L5–S1 for the revision of pseudoarthrosis and TLIF failure.

OBSERVATIONS

The patient had prior attempted L2 to S1 fusion with TLIF but suffered from hardware failure and pseudoarthrosis at the L5–S1 level. LALIF was used to facilitate same-position revision at L5–S1 in addition to further anterior column revision and reconstruction by lateral lumbar interbody fusion at the L1–2 level. Robotic posterior T10–S2 fusion was then added to provide stability to the construct and address the patient’s scoliotic deformity. No complications were noted, and the patient was followed until 1 year after the operation with a favorable clinical and radiological result.

LESSONS

Revision of a prior failed L5–S1 TLIF with an LALIF approach has technical challenges but may be advantageous for single position anterior column reconstruction under certain conditions.

An Alternative Operative Approach to Lumbar Spondylolisthesis

Lumbosacral spondylolisthesis is a frequently encountered pathology with high-grade spondylolisthesis being the least common. A circumferential construct is usually the preferred treatment as these can resist the shearing forces present at L5-S1. However, the severity of the slip, sacral inclination, and the slip angle may make a traditional anterior approach difficult to achieve. In this case series, we present three patients with axial back pain that were treated with an anterior L5-S1 transvertebral cage. This technique is intended for both grade II spondylolisthesis and high sacral slope. The L5-S1 transvertebral cage may be sufficient to prevent further listhesis, fuse the patient, and alleviate axial back pain.

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

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

Supine lateral lumbar interbody fusion: cadaveric proof of principle for simultaneous anterior and lateral approaches

BACKGROUND

Anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) are commonly performed in separate stages with a change in patient positioning to provide arthrodesis in the lumbar spine. Interest has recently emerged in performing these approaches as a single-stage surgery with the patient in the lateral decubitus position. The objective of this study was to evaluate the technical feasibility of performing minimally invasive anterolateral fixation in a single supine position.

METHODS

Two fresh-frozen cadavers were used and placed supine. Standard minimally invasive anterior access was obtained by the approach surgeon. An ALIF was performed at L5-S1 using standard techniques. A lateral incision was marked over the L4-5 disc space using fluoroscopy. Direct palpation and bimanual dissection were achieved through the same anterior incision, allowing access to the retroperitoneal space. Dilator and retractor docking was performed under fluoroscopic guidance. Direct visualization of the docking hardware through the anterior incision was used to ensure the safety of peritoneal contents and vasculature. The LLIF was then performed using standard techniques at L4-5.

RESULTS

Plain radiographs confirmed acceptable positioning of both the ALIF and LLIF grafts. No injury to the cadaveric peritoneum, vasculature, or lumbar plexus was observed. A slightly enlarged anterior incision also permitted retroperitoneal access and visualization of the L3-4 disc space.

CONCLUSION

This cadaver feasibility study demonstrates that combined minimally invasive ALIF and LLIF procedures may be performed as a single-stage with the patient in the supine position. Clinical consideration and study of this approach are warranted.

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.