Search

Introduction: The cervical sagittal vertical axis (cSVA) as another aspect of cervical alignment been recognized as one of the important factors affecting the pain and disability outcomes of cervical spine surgery. The purpose of the present study was to analyze the risk factors for increasing cSVA after cervical laminoplasty for cervical spondylotic myelopathy (CSM)., Materials and Methods: This retrospective study included 110 consecutive patients (68 males and 42 females, average age 72.6 years) who underwent laminoplasty for CSM between January 2007 and June 2018. We recorded the operative time, blood loss, Japanese Orthopaedic Association (JOA) score and the recovery rate. Radiological measurements were performed to analyze the following parameters: pre- and 1-year postoperative McGregor's slope (McGS), occiput to C2 Cobb angle (O-C2 angle), C2-C7 Cobb angle (C2-7 angle), T1-slope (T1S), C2-7 SVA (cSVA) and calculated the change (Δ). Patients were divided into two groups according to whether ΔcSVA was positive or negative. We also used Spearman's correlation coefficient and multiple regression analysis., Results: ΔC2-7 angle, ΔT1S-preoperative C2-7 angle, ΔO-C2 angle were different between the two groups significantly. Correlation analysis between the ΔcSVA and the various sagittal parameters showed some independent explanatory factors including the ΔC2-7 angle (r = - 0.25, p = 0.010), T1S-preoperative C2-7 angle (r = - 0.28, p = 0.004), postoperative O-C2 angle (r = 0.26, p = 0.007), ΔO-C2 angle (r = 0.37, p = 0.001). Multiple regression analysis revealed that ΔcSVA was associated with the T1S-preoperative C2-7 angle (β = - 0.25, p = 0.034) and ΔO-C2 angle (β = 0.32, p = 0.001)., Conclusions: The imbalance between T1S and preoperative C2-7 angle influences the change of cSVA after cervical laminoplasty. If cSVA increases postoperatively, the O-C2 angle increases to compensate and maintain the horizontal gaze., (© 2020. Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: The number of pelvic fractures based on osteoporosis has been increasing. The infra-acetabular screw (IAS), which connected both osseous columns, is a safe method of screw placement going through the infra-acetabular corridor (IAC). However, the specifics of the anatomy of IAC have been far from completely understood, especially in the Asian population. The purpose of our study was to reveal the details of the IAC using computed tomography (CT) data., Materials and Methods: Traumatized in-patients having pelvic CT scans from 2014 to 2016 were enrolled. Pediatric and adult patients with pelvic fractures and hip prostheses were excluded. The male/female ratio and distribution of patients' age were equalized manually; 40 male and 40 female patients were included. The IAC was measured on the plane of the inlet view (25° caudal) in multi-planar reconstructed CT images., Measurements: infra-acetabular diameter (IAD), anterior-posterior length of the IAC (APL), length from the starting point of the IAC to the medial edge of the pelvis (LME), length from the starting point of the IAC to the top of the pubic symphysis (LPS), and tilting on inlet plate (TIP)., Results: Age was 59 ± 22 (mean ± SD). Height was 159 ± 11 cm, and body mass index (BMI) was 22.9 ± 4.1. IAD, APL, LME, LPS, and TIP was 4.0 ± 1.3 mm, 89.5 ± 7.1 mm, 8.7 ± 3.6 mm, 57.8 ± 4.8 mm, and 4.7 ± 5.2°, respectively. Over 20% of corridors (35 of 160) were not feasible for IAS placement, because of inadequate width (less than 3.0 mm). Nine corridors (5.6%) had curvature in IAC, which meant technically demanding to insert IAS. There was no difference in IAD between male and female patients, while APL, LME, LPS, and TIP had sex-related differences., Conclusions: Surgeons should pay attention to the fact that over 20% of IACs are not feasible for infra-acetabular screw placement even with the perfect reduction of fragments when treating acetabular fractures.