Magnetic Resonance Imaging Study of Oblique Corridor and Trajectory to L1-L5 Intervertebral Disks in Lateral Position

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.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Analysis of Hidden Blood Loss and its Risk Factors in Oblique Lateral Interbody Fusion Surgery

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

The objective of this study was to evaluate the volume of hidden blood loss (HBL) and analyze its influential factors in single level oblique lateral interbody fusion (OLIF) surgery.

SUMMARY OF BACKGROUND DATA

OLIF is a minimally invasive spine surgery and is increasingly used to treat lumbar degenerative disk diseases. It is generally believed that there is less bleeding during OLIF. However, HBL during the perioperative period is commonly ignored.

MATERIALS AND METHODS

From January 2018 to December 2019, a total of 70 patients underwent single level OLIF surgery were retrospectively reviewed. The values of preoperative and postoperative hematocrit (Hct) were recorded to reckon HBL in accordance with Gross formula. The influential factors included sex, age, height, weight, body mass index, hypertension, diabetes mellitus, American Society of Anesthesiologists classification, disease etiology, surgery type, operative time, surgical corridor distance, psoas cross-sectional area, thickness of abdominal wall soft tissue, coagulation panel value, platelet count, values of Hct and hemoglobin, and intraoperative blood loss. Independent sample t test, Pearson correlation, Spearman correlation, and multivariate linear regression analysis were performed to investigate the risk factors related to HBL.

RESULTS

The average volume of HBL was 809 mL and the average hemoglobin loss was 27.1 g/L in OLIF procedure. Multiple linear regression analysis revealed that thickness of abdominal wall soft tissue was the independent risk factor for HBL (P=0.008). Whereas age (P=0.414), activated partial thromboplastin time (P=0.314), preoperative value of Hct (P=0.854), disease etiology (P=0.362), operative time (P=0.389), and intraoperative blood loss (P=0.912) were not statistically associated with HBL.

CONCLUSIONS

HBL was substantial and the average volume of HBL was 809 mL in single level OLIF surgery. The thickness of abdominal wall soft tissue was the risk factor of HBL. Accurate assessment of HBL can prevent perioperative complications and ensure patients' safety.