Koji Tamai1,2, Zorica Buser3, Permsak Paholpak1, Kittipong Sessumpun1, Patrick C Hsieh4, Hiroaki Nakamura2, Jeffrey C Wang1. 1. Department of Orthopaedic Surgery, Keck School of Medicine, University of Southern California, 1450 Biggy Street, NRT-4513, Los Angeles, CA, 90033, USA. 2. Department of Orthopedics, Graduate School of Medicine, Osaka City University, Osaka, Japan. 3. Department of Orthopaedic Surgery, Keck School of Medicine, University of Southern California, 1450 Biggy Street, NRT-4513, Los Angeles, CA, 90033, USA. zbuser@usc.edu. 4. Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, USA.
Abstract
PURPOSE: Although the T1 vertebra is considered as an important factor of cervical balance, little is known about its motion between flexion and extension. The purpose of present study was to analyze the T1 sagittal motion using kinematic magnetic resonance imaging (kMRI), and to identify factors that relate to T1 sagittal motion. METHODS: We retrospectively analyzed 145 kMR images taken in weight-bearing neutral, flexion and extension positions. Cervical balance parameters were evaluated in each position. The degree of T1 sagittal motion was defined as [(T1 slope at extension) - (T1 slope at flexion)]. All patients were divided into three groups: Positive group (T1 followed the head motion, T1 sagittal motion > 5°), Stable group (5 ≥, ≥ - 5) and Negative group (T1 moved in the opposite direction from the head motion, > - 5). The groups were compared and multivariate logistic regression analysis was calculated. RESULTS: There were 57 (40%) patients in the positive, 56 (39%) in the stable and 32 (22%) in the negative group. The positive group had the largest C2-7 sagittal vertical axis in flexion (p < 0.001) and the shortest in the extension (p = 0.023). Similar trends were seen in cranial tilt and cervical tilt. The value of T1 height < 27 mm was a significant independent factor for the negative group (p = 0.008, adjusted odds ratio = 5.958). CONCLUSION: Based on T1 sagittal motion, 40% of the patients were classified in positive group (the T1 vertebra followed the head motion in flexion and extension), and 20% were classified in the negative group (the T1 vertebra moved in the opposite direction from the head motion). T1 height < 27 mm was a potential predictor of negative group.
PURPOSE: Although the T1 vertebra is considered as an important factor of cervical balance, little is known about its motion between flexion and extension. The purpose of present study was to analyze the T1 sagittal motion using kinematic magnetic resonance imaging (kMRI), and to identify factors that relate to T1 sagittal motion. METHODS: We retrospectively analyzed 145 kMR images taken in weight-bearing neutral, flexion and extension positions. Cervical balance parameters were evaluated in each position. The degree of T1 sagittal motion was defined as [(T1 slope at extension) - (T1 slope at flexion)]. All patients were divided into three groups: Positive group (T1 followed the head motion, T1 sagittal motion > 5°), Stable group (5 ≥, ≥ - 5) and Negative group (T1 moved in the opposite direction from the head motion, > - 5). The groups were compared and multivariate logistic regression analysis was calculated. RESULTS: There were 57 (40%) patients in the positive, 56 (39%) in the stable and 32 (22%) in the negative group. The positive group had the largest C2-7 sagittal vertical axis in flexion (p < 0.001) and the shortest in the extension (p = 0.023). Similar trends were seen in cranial tilt and cervical tilt. The value of T1 height < 27 mm was a significant independent factor for the negative group (p = 0.008, adjusted odds ratio = 5.958). CONCLUSION: Based on T1 sagittal motion, 40% of the patients were classified in positive group (the T1 vertebra followed the head motion in flexion and extension), and 20% were classified in the negative group (the T1 vertebra moved in the opposite direction from the head motion). T1 height < 27 mm was a potential predictor of negative group.
Authors: Christopher P Ames; Benjamin Blondel; Justin K Scheer; Frank J Schwab; Jean-Charles Le Huec; Eric M Massicotte; Alpesh A Patel; Vincent C Traynelis; Han Jo Kim; Christopher I Shaffrey; Justin S Smith; Virginie Lafage Journal: Spine (Phila Pa 1976) Date: 2013-10-15 Impact factor: 3.468
Authors: Jessica A Tang; Justin K Scheer; Justin S Smith; Vedat Deviren; Shay Bess; Robert A Hart; Virginie Lafage; Christopher I Shaffrey; Frank Schwab; Christopher P Ames Journal: Neurosurgery Date: 2012-09 Impact factor: 4.654
Authors: Chong Weng; Justin Wang; Alexander Tuchman; Jian Wang; Changfeng Fu; Patrick C Hsieh; Zorica Buser; Jeffrey C Wang Journal: Spine (Phila Pa 1976) Date: 2016-02 Impact factor: 3.468
Authors: Akinobu Suzuki; Michael D Daubs; Hirokazu Inoue; Tetsuo Hayashi; Bayan Aghdasi; Scott R Montgomery; Monchai Ruangchainikom; Xueyu Hu; Christopher J Lee; Christopher J Wang; Benjamin J Wang; Hiroaki Nakamura Journal: Spine (Phila Pa 1976) Date: 2013-08-01 Impact factor: 3.468