Elimination of Lumbar Plexus Injury by Changing the Entry Point and Traction Direction of the Psoas Major Muscle in Transpsoas Lateral Lumbar Spine Surgery

Background and Objectives: The lateral approach is commonly used for anterior column reconstruction, indirect decompression, and fusion in patients with lumbar degenerative diseases and spinal deformities. However, intraoperative lumbar plexus injury may occur. This is a retrospective comparative study to investigate and compare neurological complications between the conventional lateral approach and a modified lateral approach at L4/5. Materials and Methods: Patients with a lumbar degenerative disease requiring single-level intervertebral fusion at L4/5 were included and categorized into group X and group A. Patients in group X underwent conventional extreme lateral interbody fusion, while those in group A underwent a modified surgical procedure that included splitting of the anterior third of the psoas muscle, which was dilated by the retractor on the anterior third of the intervertebral disc. The incidence of lumbar plexus injury, defined as a decrease of ≥1 grade on manual muscle testing of hip flexors and knee extensors and sensory impairment of the thigh for ≥3 weeks, on the approach side, was investigated. Results: Each group comprised 50 patients. No significant between-group differences in age, sex, body mass index, and approach side were observed. There was a significant between-group difference in intraoperative neuromonitoring stimulation value (13.1 ± 5.4 mA in group X vs. 18.5 ± 2.3 mA in group A, p < 0.001). The incidence of neurological complications was significantly higher in group X than in group A (10.0% vs. 0.0%, respectively, p < 0.05). Conclusions: In our modified procedure, the anterior third of the psoas muscle was entered and split, and the intervertebral disc could be reached without damaging the lumbar plexus. When performing lumbar surgery using the lateral approach, lumbar plexus injury can be avoided by following surgical indication criteria based on the location of the lumbar plexus with respect to the psoas muscle and changing the transpsoas approach to the intervertebral disc.

Cadaveric Evidence of Complete Transection of the Lumbar Sympathetic Trunk After Extreme Lateral Transpsoas Approach to the Lumbar Spine: A Word of Caution

Lateral transpsoas approaches to the lumbar spine are believed to entail less risk of injury to the lumbar sympathetic trunk and plexus than anterior approaches. However, even the lateral approach can occasionally injure the sympathetic trunk. We report a literature review and cadaveric case of complete resection of the left sympathetic trunk at L3 following lateral transpsoas approach performed by a well-trained spine surgeon. A left lateral approach to the lumbar spine for a two-level total discectomy at L3-L4 and L4-L5 was undertaken on a fresh-frozen cadaver by an experienced spinal surgeon. The procedure followed standard spinal technique under fluoroscopy guidance. The cadaver was placed in a right lateral position and an operative corridor to the lateral aspect of the psoas major muscle was developed. Blunt dissection was carried through the muscle and standard total discectomy was completed at the target levels. Following the procedure, the lumbar spine and adjacent structures were anatomically dissected. It was found that the sympathetic trunk had been completely transected at the L3 level during the surgical procedure. Other major structures such as the femoral nerve, obturator nerve, and roots of the lumbar spinal nerves had not been injured. The above case highlights the proximity of the sympathetic trunk to lateral transpsoas approaches and the possibility of injury to it. We review the literature on postoperative cases of lumbar sympathetic dysfunction (SD) following such procedures and posit that some of these are due to direct iatrogenic injury.

The impact of age on approach-related complications with navigated lateral lumbar interbody fusion

OBJECTIVE

Age is known to be a risk factor for increased complications due to surgery. However, elderly patients can gain significant quality-of-life benefits from surgery. Lateral lumbar interbody fusion (LLIF) is a minimally invasive procedure that is commonly used to treat degenerative spine disease. Recently, 3D navigation has been applied to LLIF. The purpose of this study was to determine whether there is an increased complication risk in the elderly with navigated LLIF.

METHODS

Patients who underwent 3D-navigated LLIF for degenerative disease from 2014 to 2019 were included in the analysis. Patients were divided into elderly and nonelderly groups, with those 65 years and older categorized as elderly. Ninety-day medical and surgical complications were recorded. Patient and surgical characteristics were compared between groups, and multivariate regression analysis was used to determine independent risk factors for complication.

RESULTS

Of the 115 patients included, 56 were elderly and 59 were nonelderly. There were 15 complications (25.4%) in the nonelderly group and 10 (17.9%) in the elderly group, which was not significantly different (p = 0.44). On multivariable analysis, age was not a risk factor for complication (p = 0.52). However, multiple-level LLIF was associated with an increased risk of approach-related complication (OR 3.58, p = 0.02).

CONCLUSIONS

Elderly patients do not appear to experience higher rates of approach-related complications compared with nonelderly patients undergoing 3D navigated LLIF. Rather, multilevel surgery is a predictor for approach-related complication.

Localization of the Lumbar Plexus in the Psoas Muscle: Considerations for Avoiding Lumbar Plexus Injury during the Transpsoas Approach

Introduction

Transpsoas lumbar spine surgery is minimally invasive and has very good corrective effects. However, approach-side nerve complications delay post-operative rehabilitation. We anatomically investigated the localization of the lumbar plexus running in the psoas muscle.

Methods

We examined 27 formalin-fixed cadavers. The left-sided psoas muscle was extracted and cut parallel to the intervertebral disc at the L2/3, L3/4, and L4/5 disc levels. Using digitized photographs, we calculated the ratio of the distance from the front edge of the psoas muscle to the center of the lumbar plexus in the anteroposterior diameter of the psoas muscle (%). Then, we calculated the ratio of the distance from the lateral edge of the psoas muscle to the center of the lumbar plexus in the lateral diameter of the psoas muscle (%).

Results

The anterior-posterior lumbar plexus localization was 74.5 at L2/3, 74.7 at L3/4, and 81.2 at L4/5. There was a significant difference between L2/3 and L4/5 and between L3/4 and L4/5, but not between L2/3 and L3/4 (P=0.02, 0.01, and 0.94, respectively). The lateral and medial lumbar plexus localization was 85.4 at L2/3, 83.9 at L3/4, and 77.7 at L4/5. There was a significant difference between L2/3 and L4/5 and between L3/4 and L4/5, but not between L2/3 and L3/4 (P=0.01, 0.04, and 0.41, respectively).

Conclusions

The lumbar plexus was localized in the posterior one-third and medial one-third of the psoas muscle and moved to a posterolateral location at L4/5. To avoid neuropathy, consider the psoas muscle's position relative to that of the intervertebral disc. It is essential to understand lumbar plexus localization in the psoas muscle when looking directly at this muscle to enter the pricking point or route with a lower risk of nerve damage.

Anterior corpectomy via the mini-open, extreme lateral, transpsoas approach combined with short-segment posterior fixation for single-level traumatic lumbar burst fractures: analysis of health-related quality of life outcomes and patient satisfaction

OBJECTIVE

The authors present clinical outcome data and satisfaction of patients who underwent minimally invasive vertebral body corpectomy and cage placement via a mini-open, extreme lateral, transpsoas approach and posterior short-segment instrumentation for lumbar burst fractures.

METHODS

Patients with unstable lumbar burst fractures who underwent corpectomy and anterior column reconstruction via a mini-open, extreme lateral, transpsoas approach with short-segment posterior fixation were reviewed retrospectively. Demographic information, operative parameters, perioperative radiographic measurements, and complications were analyzed. Patient-reported outcome instruments (Oswestry Disability Index [ODI], 12-Item Short Form Health Survey [SF-12]) and an anterior scar-specific patient satisfaction questionnaire were recorded at the latest follow-up.

RESULTS

Twelve patients (7 men, 5 women, average age 42 years, range 22-68 years) met the inclusion criteria. Lumbar corpectomies with anterior column support were performed (L-1, n = 8; L-2, n = 2; L-3, n = 2) and supplemented with short-segment posterior instrumentation (4 open, 8 percutaneous). Four patients had preoperative neurological deficits, all of which improved after surgery. No new neurological complications were noted. The anterior incision on average was 6.4 cm (range 5-8 cm) in length, caused mild pain and disability, and was aesthetically acceptable to the large majority of patients. Three patients required chest tube placement for pleural violation, and 1 patient required reoperation for cage subsidence/hardware failure. Average clinical follow-up was 38 months (range 16-68 months), and average radiographic follow-up was 37 months (range 6-68 months). Preoperative lumbar lordosis and focal lordosis were significantly improved/maintained after surgery. Patients were satisfied with their outcomes, had minimal/moderate disability (average ODI score 20, range 0-52), and had good physical (SF-12 physical component score 41.7% ± 10.4%) and mental health outcomes (SF-12 mental component score 50.2% ± 11.6%) after surgery.

CONCLUSIONS

Anterior corpectomy and cage placement via a mini-open, extreme lateral, transpsoas approach supplemented by short-segment posterior instrumentation is a safe, effective alternative to conventional approaches in the treatment of single-level unstable burst fractures and is associated with excellent functional outcomes and patient satisfaction.

Outcomes of Two Different Techniques Using the Lateral Approach for Lumbar Interbody Arthrodesis

Study Design Retrospective cohort study. Objective To determine the short-term outcomes of two different lateral approaches to the lumbar spine. Methods This was a retrospective review performed with four fellowship-trained spine surgeons from a single institution. Two different approach techniques were identified. (1) Traditional transpsoas (TP) approach: dissection was performed through the psoas performed using neuromonitored sequential dilation. (2) Direct visualization (DV) approach: retractors are placed superficial to the psoas followed by directly visualized dissection through psoas. Outcome measures included radiographic fusion and adverse event (AE) rate. Results In all, 120 patients were identified, 79 women and 41 men. Average age was 64.2 years (22 to 86). When looking at all medical and surgical AEs, 31 patients (25.8%) had one or more AEs; 22 patients (18.3%) had a total of 24 neurologically related AEs; 15 patients (12.5%) had anterior/lateral thigh dysesthesias; 6 patients (5.0%) had radiculopathic pain; and 3 patients (2.5%) had postoperative weakness. Specifically, for neurologic AEs, the DV group had a rate of 28.0% and the TP group had a rate of 14.2% (p < 0.18). When looking at the rate of neurologic AEs in patients undergoing single-level fusions only, the DV group rate was 28.6% versus 10.2% for the TP group (p < 0.03). Conclusion Overall, 18.3% of patients sustained a postoperative neurologic AE following lateral interbody fusions. The TP approach had a statistically lower rate of neurologic-specific AE for single-level fusions.