Pedicle Subtraction Osteotomy in Lateral Position: A New Strategy for Correcting Severe Thoracolumbar Kyphosis Combined with Hip Flexion Contracture in Ankylosing Spondylitis

Abstract

Objective: To describe spinal osteotomy in lateral position, which might be a new strategy for correcting thoracolumbar kyphotic deformity combined with severe hip flexion contracture, and to present two cases in which this method was successfully performed.Methods: Spinal osteotomies in lateral position were performed in two patients with severe thoracolumbar kyphosis combined with hip flexion contracture, which was not suitable for operation in the prone position. Case 1: a 33-year-old female AS patient still had severe hip flexion contracture due to poor rehabilitation after total hip replacement (THR). The range of movement of the hip was only about 15 in right and 10 in left. Pre-operativethoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), and sagittal vertical axis (SVA) were 52.4 , 49.1 , 42.7 , and 315 mm, respectively. Pedicle subtraction osteotomy (PSO) at L3 was performed in the lateral position. The eggshell procedure was used during osteotomy. Case 2: a 45-year-old male AS patient presented coexisting rigid thoracolumbar kyphosis and hip flexion contracture. The range of movement of the hip was only about 20 in right and 25 in left. Pre-operativeTK, TLK, LL and SVA were 34.9 , 66.8 , 58.8 and 290.8 mm, respectively. PSO at L 2 was performed in lateral position. The eggshell procedure was also used.Results: Sagittal malalignments of both patients were greatly improved. For case 1, the total operation time was 5.5 h. The blood loss was 1500 mL and the amount of allogeneic blood transfusion was 1580 mL during the operation. SVA was reduced to 127 mm and LL decreased from preoperative 42.7 to À28.4 . The correction angle through L 3 was 34.7 and the correction angle through the osteotomy segment was 62.9 . For case 2, the duration of surgery was 6.5 h. The operative blood loss was 2000 mL and the total amount of blood transfusion was 2020 mL. SVA was reduced to 209.8 mm and LL decreased from preoperative 58.8 to 9.2 .The correction angle through L 2 was 37.1 and the correction angle through the osteotomy segment was 55 . No intra-operative or post-operative complications were observed. Six months after PSO, case 1 had good posture for standing and sitting. The case 2 underwent bilateral THRs nine months after PSO. Conclusion:PSO could be performed in the lateral position successfully. For AS patients who cannot be placed in the prone position due to coexisting severe thoracolumbar kyphosis and hip flexion contracture, performing spinal osteotomy in the lateral position as the first step is an alternative.

A Femoral Neck Osteotomy for the Patients with Ankylosing Spondylitis and Thoracolumbar Kyphosis Combined with Hip Flexion Contracture

“… 1 Some surgeons have performed PSO in the lateral position to avoid the difficulties associated with the patient's body position. 10 This article reported only two such cases. The surgeon needed two off‐table staff to push the shoulders and pelvis of the patient to extend the lumbar slowly and simultaneously.…”

“…This maneuver not only closes the osteotomy but also allows greater correction of the sagittal plane deformity through the osteotomy 1 . Some surgeons have performed PSO in the lateral position to avoid the difficulties associated with the patient's body position 10 . This article reported only two such cases.…”

Operative strategies for ankylosing spondylitis-related thoracolumbar kyphosis: focus on the cervical stiffness, coronal imbalance and hip involvement

“…For patients with fused hip in non-functional flexion position, we conducted femoral neck amputation first, followed by spinal osteotomy in prone position and total hip arthroplasty [ 6 ]. Another option is to perform spinal surgery first in the lateral position [ 13 , 33 ].…”

“…Third, we used a cervical ROM of 30° and hip ROM of 90° as the critical value mainly based on our limited experiences rather than a controlled study. Although the above ranges of mobilities were reported probably enough to meet the requirements of daily activities [ 3 , 33 ], the exact ranges are worth further study. Fourth, we did not particularly address the treatment of thoracic kyphosis in the classification.…”

Mini‐open Pedicle Subtraction Osteotomy versus Standard Posterior Approach for Ankylosing Spondylitis‐related Spinal Kyphosis: A Comparative Study

“…The prevalence of AS in the adult population is between 0.9% and 1.4%, with male predominance 1,5 . AS‐related spinal kyphosis is a debilitating condition that results in sagittal spinopelvic imbalance and impaired horizontal gaze 6 and affects more than 30% of patients with AS, thereby placing a large burden on their families 7–9 . The best treatment for AS‐related spinal kyphosis is corrective osteotomy, the most common types of which are pedicle subtraction osteotomy (PSO), Smith–Peterson osteotomy, and vertebral column decancellation 1,3,7,10 …”