Segmental Lordosis Gain Is a Prognostic Radiological Factor of Good Functional Outcome After the Implantation of a Single-Level Prosthesis or a Hybrid Construct for Lumbar Disc Degeneration

Prone Transpsoas Lateral Interbody Fusion (PTP LIF) with Anterior Docking: Preliminary functional and radiographic outcomes

Background

Disadvantages of lateral interbody fusion (LIF) through a direct, transpsoas approach include difficulties associated with lateral decubitus positioning and limited sagittal correction without anterior longitudinal ligament release or posterior osteotomy. Prior technical descriptions advocate anchoring or docking the retractor into the posterior to middle aspect of the disc space.

Methods

72 patients who underwent 116 total levels of Prone Transpsoas (PTP) LIF with anterior docking with a single surgeon between December 2021 and May 2023 were included. Patient characteristics, perioperative data, as well as postoperative functional and radiographic outcomes were recorded. Subgroup analysis was performed for patients who underwent single-level PTP LIF with single-level percutaneous fixation (SLP). Patients in the SLP subgroup did not undergo direct decompression, release, or osteotomy.

Results

N=41 (56.9%) of cases included the L4-5 level. No vascular, bowel, or other visceral complications occurred. No patients developed a permanent motor deficit. Both the total cohort and the SLP group demonstrated statistically significant improvements in functional outcomes including Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) as well as all radiographic parameters measured. Mean total operative time (incision to completion of closure for lateral and posterior fusion) in the SLP group was 104.3 minutes with a significant downward trend with increasing surgeon experience. The SLP group demonstrated a 9.9° increase in segmental lordosis (SL), a 7.5° increase in lumbar lordosis (LL), 5.3° reduction in pelvic tilt (PT), and a decrease in pelvic incidence - lumbar lordosis mismatch (PI-LL) from 11.0° preoperatively to 3.9°, postoperatively (p<.01).

Conclusions

PTP LIF with anterior docking may address shortcomings associated with traditional lateral interbody fusion by producing safe and reproducible access with improved restoration of segmental lordosis and optimization of spinopelvic parameters.

Comparison of segmental lordosis gain of prone transpsoas (PTP) vs. lateral lumbar interbody fusion

INTRODUCTION

Lumbar interbody fusion is a standard method to treat certain degenerative conditions that are refractory to conservative treatments. LLIF reduces posterior muscle damage, can relieve neurological symptoms through indirect decompression, provides increased stability with its wider cages, and promotes more significant segmental lordosis than standard posterior techniques. However, the technique possesses its issues, such as unusual positioning, possible plexus-related symptoms, and median segmental lordosis correction. Trying to ease those issues, the idea of a prone transpsoas technique occurred.

METHODS

Retrospective, single-centric, comparative, and non-randomized study. The authors paired patients receiving lateral lumbar interbody fusion (LLIF) or prone transpsoas (PTP) to evaluate the technique's impact on the segmental lordosis correction. A correlation test selected the covariates for the matching. p-Values inferior to 0.05 were deemed significant.

RESULTS

Seventy-one patients were included in the analysis, 53 in the LLIF group and 18 in the PTP group. The significant covariates to the segmental lordosis correction were technique, preoperative segmental lordosis, cage position, and preoperative pelvic tilt. After the paring model, PTP showed significant segmental lordosis correction potential regarding the LLIF.

CONCLUSION

The prone transpsoas approach can significantly enhance the correction of segmental lordosis proportionated to the traditional LLIF approach.

Anterior Longitudinal Ligament Flap Technique: Description of Anterior Longitudinal Ligament Opening During Anterior Lumbar Spine Surgery and Review of Vascular Complications in 189 Patients

BACKGROUND

One of the main concerns of anterior lumbar spine approaches are vascular complications. The aim of our study is to provide technical details about a flap technique using the anterior longitudinal ligament (ALL) when approaching the lumbar spine via an anterior corridor. This can help decrease complications by protecting the adjacent vascular structures. We also include a retrospective cohort review.

METHODS

This is a retrospective bicentric study: 189 patients with a mean age of 44.2 years underwent anterior lumbar spine surgery using the ALL flap technique. Patients were diagnosed with degenerative pathologies. We treated 239 lumbar levels primarily at the L4-5 and L5-S1: 88 single-level anterior lumbar interbody fusions, 9 two-level ALIFs, 51 total disk replacements (TDR), and 41 hybrid constructs (i.e., ALIF L5S1 and TDR L4L5). Anterior approaches were performed by two senior spine surgeons. The ALL flap technique was utilized in all of these cases, by carefully dissecting the ALL, with the flap suspended using sutures. As such, this ALL flap provided a "safe corridor" to avoid any potential vascular laceration.

RESULTS

The operative and early surgical complication rate was 3.2%. There was no arterial injury. There were only 2 minor venous lacerations (1.05%). No blood transfusion was required. Neither lacerations happened during disk space preparation.

CONCLUSIONS

Here, we provide technical details about a simple and reproducible technique using the ALL as a flap, which may help spine surgeons minimize vascular injuries during ALIF or even TDR surgeries.