# Surgical treatment of special type of adjacent segment disease – lumbar intraspinal synovial cysts in patients with osteoporosis: A case report

## TL;DR

This case report describes a rare surgical treatment for a lumbar synovial cyst in an osteoporotic patient, using a hybrid approach to address spinal instability and prevent further complications.

## Contribution

A novel surgical strategy combining cyst excision, cement-reinforced fixation, and semi-rigid stabilization for osteoporotic patients with synovial cysts.

## Key findings

- The hybrid approach effectively addressed spinal instability and cyst removal in an osteoporotic patient.
- Cement augmentation increased pedicle screw pullout resistance in osteoporotic bone.
- Waveflex semi-rigid fixation reduced adjacent segment loading compared to rigid rods.

## Abstract

This paper presents a case of lumbar intraspinal synovial cysts (LISCs) associated with secondary osteoporosis, contributing to current understanding of LISC pathogenesis and offering a safe, effective surgical strategy tailored to complex clinical conditions.

A 61-year-old woman with a history of rheumatoid arthritis and osteoporosis (lumbar spine T-score: −2.6) underwent posterior lumbar interbody fusion (PLIF) at the L4/5 segment for lumbar disc herniation and spondylolisthesis, as confirmed by MRI.

Ten months postoperatively, she developed a synovial cyst at the L3/4 segment, accompanied by a fracture of the L5 pedicle screw. Therefore, she underwent a revision surgery involving cyst excision, bone cement-reinforced screw fixation, and Waveflex semi-rigid rod implantation. The postoperative recovery was smooth, and no neurological abnormalities were found during the 9-month follow-up.

The surgical strategy effectively addressed three major challenges: excision of the cyst in the context of compromised spinal stability, revision fixation in osteoporotic bone using cement augmentation, and mitigation of adjacent segment degeneration (ASD) through motion-preserving Waveflex semi-rigid stabilization.

The combination of cyst resection, Waveflex semi-rigid fixation, and cement-reinforced screw placement demonstrated favorable safety and efficacy in revision lumbar fusion for patients with secondary osteoporosis.

•Lumbar intraspinal synovial cysts are rare in osteoporotic patients.•Diagnosis was confirmed by imaging and histopathology.•The new internal fixation system reduced the loading of adjacent segments compared to conventional rigid titanium rods.•Cement augmentation of the fractured pedicle screw increased pullout resistance.•This hybrid approach combines cyst resection, Waveflex semi-rigid fixation, and cement-reinforced screw placement.

Lumbar intraspinal synovial cysts are rare in osteoporotic patients.

Diagnosis was confirmed by imaging and histopathology.

The new internal fixation system reduced the loading of adjacent segments compared to conventional rigid titanium rods.

Cement augmentation of the fractured pedicle screw increased pullout resistance.

This hybrid approach combines cyst resection, Waveflex semi-rigid fixation, and cement-reinforced screw placement.