Keun-Ho Lee, Ki-Tack Kim, Yong-Chan Kim, Joong-Won Lee, and Kee-Yong Ha
The purpose of this study was to investigate the rate of and the risk factors for surgery-related complications demonstrated on radiography after pedicle subtraction osteotomy (PSO) for thoracolumbar kyphosis in patients with ankylosing spondylitis (AS).
The authors retrospectively reviewed the medical records of 230 consecutive patients with thoracolumbar kyphosis due to AS who had undergone 1-level PSO at a single institution in the period from 2010 to 2017. The causes of surgery-related complications were divided into two types: surgical/technical failure and mechanical failure.
The patients consisted of 20 women and 210 men, with an average age of 43.4 years. The average follow-up period was 39.0 months. The preoperative sagittal vertical axis was 18.5 ± 69.3 cm, which improved to 4.9 ± 4.6 cm after PSO. Of the 77 patients (33.5%) who experienced minor or major surgery-related complications, 56 had complications related to surgical/technical failure (overall incidence 24.3%) and 21 had complications related to mechanical failure (overall incidence 9.1%). Fourteen patients (6.1%) underwent reoperation. However, among the 77 patients with complications, the rate of revision surgery was 18.2%. The most common radiological complications were as follows: sagittal translation in 24 patients, coronal imbalance in 20, under-correction in 8, delayed union in 8, and distal junctional failure and kyphosis in 8. The most common causes of reoperation were coronal imbalance in 4 patients, symptomatic malposition of pedicle screws in 3, and distal junctional failure in 3. Delayed union was statistically correlated with posterior sagittal translation (p = 0.007).
PSO can provide acceptable radiographic outcomes for the correction of thoracolumbar kyphosis in patients with AS. However, a high incidence of surgery-related complications related to mechanical failure and surgical technique can develop. Thorough radiographic investigation before and during surgery is needed to determine whether complete ossification occurs along the anterior and posterior longitudinal ligaments of the spine.
Se-Jun Park, Keun-Ho Lee, Chong-Suh Lee, Joon Young Jung, Jin Ho Park, Gab-Lae Kim, and Ki-Tack Kim
The goal of this study was to evaluate the radiographic and clinical results of instrumentation surgery without fusion for metastases to the spine.
Between 2010 and 2017, patients with spinal tumors who underwent instrumentation without fusion surgery were consecutively evaluated. Preoperative and postoperative clinical data were evaluated. Data were inclusive for last follow-up and just prior to death if the patient died. Instrumentation-related complications included screw migration, screw or rod breakage, cage migration, and screw loosening.
Excluding patients who died within 6 months, a total of 136 patients (140 operations) were recruited. The average follow-up duration was 16.5 months (median 12.4 months). The pain visual analog scale score decreased from 6.4 to 2.5 (p < 0.001) and the Eastern Cooperative Oncology Group scale score improved (p < 0.001). There were only 3 cases (2.1%) of symptomatic instrumentation-related complications that resulted in revisions. There were 6 cases of nonsymptomatic complications. The most common complication was screw migration or pull-out (5 cases). There were 3 cases of screw or rod breakage and 1 case of cage migration. Two-thirds of the cases of instrumentation-related complications occurred after 6 months, with a mean postoperative period of 1 year.
The current study reported successful outcomes with very low complication rates after nonfusion surgery for patients with spinal metastases, even among those who survived for more than 6 months. More than half of the instrumentation-related complications were asymptomatic and did not require revision. The results suggest that nonfusion surgery might be sufficient for a majority of patients with spinal metastases.
Yong-Chan Kim, Ji Hao Cui, Ki-Tack Kim, Gyu-Taek Park, Keun-Ho Lee, Sung-Min Kim, and Lawrence G. Lenke
In this study, the authors’ goal was to develop and validate novel radiographic parameters that better describe total body sagittal alignment (TBSA).
One hundred sixty-six consecutive operative spinal deformity patients were evaluated using full-body stereoradiographic imaging. Seven TBSA parameters were measured and then correlated to 6 commonly used spinopelvic measurements. TBSA measures consisted of 4 distance measures relating the cranial center of mass (CCOM) to the sacrum, hips, knees, and ankles, and 3 angular measures relating the CCOM to the hips, knees, and ankles. Furthermore, each TBSA parameter was correlated to patient-reported outcome (PRO) scores using the Oswestry Disability Index (ODI) and Scoliosis Research Society–22 (SRS-22) instruments. Thirty patients were randomly selected for inter- and intraobserver reliability testing of the TBSA parameters using intraclass correlation coefficients (ICCs).
All TBSA radiographic parameters demonstrated strong linear correlation with the currently accepted primary measure of sagittal balance, the C7 sagittal vertical axis (r = 0.55–0.96, p < 0.001). Moreover, 5 of 7 TBSA measures correlated strongly with ODI and SRS-22 total scores (r = 0.42–0.51, p < 0.001). Inter- and intraobserver reliability for all TBSA measures was good to excellent (interrater ICC = 0.70–0.98, intrarater ICC = 0.77–1.0).
In spine deformity patients, novel TBSA radiographic parameters correlated well with PROs and with currently utilized spinal sagittal measurements. Inter- and intrarater reliability was high for these novel parameters. This is the first study to propose a reliable method for measuring head-to-toe global spinal alignment.