Surgical Treatment Strategies for Ankylosing Spondylitis with “Folded Man” Deformity: A Single-Center Retrospective Case Series Study

Abstract

Ankylosing spondylitis (AS) combined with severe kyphotic deformity can cause the trunk to collapse, pressing tightly against the front of the thighs and forming a "folded man" deformity. The purpose of this article is to evaluate the effectiveness and safety of a treatment strategy for correcting the "folded man" deformity. A retrospective study was conducted to analyze 12 AS patients with "folded man" deformity treated at our hospital with staged kyphosis correction in the lateral position, followed by total hip arthroplasty, from May 2018 to July 2021. Global kyphosis (GK), thoracic kyphosis, lumbar lordosis, sagittal vertical axis, chin-brow vertical angle, and Scoliosis Research Society-22 Patient Questionnaire scores were compared preoperation and postoperation. Surgical duration, positioning time, blood loss, and complications were also recorded and analyzed. All patients demonstrated a correction of the "folded man" deformity, achieving sagittal balance and horizontal gaze with mild complications. Postoperatively, there were significant improvements in spinal sagittal parameters (GK, thoracic kyphosis, lumbar lordosis, and sagittal vertical axis) and chin-brow vertical angle compared to preoperative values (P < 0.05). The preoperative GK of 139.6 ± 9.1° was corrected to 55.3 ± 5.7° postoperatively, with a mean correction of 84.3°. The standardized treatment strategy involving staged correction of spinal kyphosis in a lateral position, followed by subsequent total hip arthroplasty, offers a safe and effective solution for managing AS with "folded man" deformity.