# Clinical, Radiological, and Functional Evaluations of the Anterior-to-Psoas Lumbar Interbody Fusion Approach With Posterior Decompression and Osteotomy for Treating Patients With Adult Spinal Deformity: A Retrospective Study

## TL;DR

This study shows that a two-stage surgical approach using expandable spacers and osteotomy improves outcomes for adult spinal deformity patients.

## Contribution

The study introduces a minimally invasive two-stage surgical technique for ASD with high fusion rates and functional improvements.

## Key findings

- Patients showed significant pain reduction and improved quality of life after 12 months.
- Radiographic data showed 100% fusion rate and improved lumbar lordosis and disc height.
- Surgical outcomes were comparable to traditional osteotomy methods with fewer complications.

## Abstract

Objective: Degenerative adult spinal deformity (ASD) is a prevalent disease in the elderly population. Treating it typically requires an extensive surgical intervention. This study aimed to assess the use of expandable spacers for multi-level anterior-to-psoas lumbar interbody fusion (ATP-LIF) along with posterior direct decompression and osteotomy to treat patients with degenerative ASD.

Method: This was a single-center retrospective study of ASD patients (anyone undergoing fusion procedure for four or more spinal levels) undergoing two-stage surgery with expandable interbody spacers with a minimum follow-up period of around 12 months between November 2019 and June 2021. A total of 20 patients were enrolled in this study (15 patients = four-level fusion, five patients = five-level fusion). Exclusion criteria included <18 years of age, pregnancy, tumor, and trauma patients. Demographic, surgical, radiographic, complications, and patient-reported outcomes (PROs) were collected.

Results: Of the 20 patients included (mean age = 68.1 ± 9.0 years, mean body mass index = 30.5 ± 7.4 kg/m2, 12 males and eight females), surgical data showed a mean total operation time of 315 ± 180.6 mins and mean total blood loss of 638.8 ± 37.6 mL. At 12 months, 18/20 patients returned for follow-up. There was a significant reduction in the mean visual analog scale (VAS) back pain scores (Δ = 2.1, p < 0.05), an increase in the 12-item short-form health survey (SF-12) (Δ = 5.6, p < 0.05), and improvement in pelvic incidence-lumbar lordosis (PI-LL) (Δ = 15.8°, p < 0.05) at the final follow-up, as compared with the preoperative baseline. Moreover, at 12 months follow-up, radiographic data showed 100% fusion rate (18/18), lumbar lordosis (Δ = 13.9°), and disc height improvement (Δ = 4.1 mm), as well as a reduction in the coronal cobb angle (Δ = 6.9°) as compared to the preoperative baseline.

Conclusion: Two-stage ATP-LIF with expandable spacers along with posterior direct decompression and Ponte osteotomy is a viable minimally invasive treatment for patients with ASD. This was evidenced by similar surgical outcomes to pedicle subtraction osteotomy, improvements in PROs, restoration of PI-LL, high fusion rates, and a significant increase in disc height.