Department of Orthopedics, Second Military Medical University Affiliated Changzheng Hosipital, #415 Fengyang Road, Shanghai, PR China.
Med Hypotheses. 2011 Sep;77(3):456-9. doi: 10.1016/j.mehy.2011.06.009. Epub 2011 Jul 18.
Cervical kyphosis may be congenital, or occur as a result of laminectomy, post-traumatic deformity, infection, neuromuscular disorders such as muscular dystrophies, motor neuron disorders such as amyotrophic lateral sclerosis, tumor, and inflammation such as ankylosing spondylitis. Furthermore, adolescent idiopathic cervical kyphosis was defined as cervical kyphotic deformity of adolescent patient without any cause such as those previously described. As no standard values for "cervical kyphosis" could be found in the literature, many reported studies only report a subjective classification, "kyphotic, straight or lordotic". But this method had proven to be unreliable. Grob et al. defined "straight" for the global curvature as +4° to -4°, and lordotic and kyphotic as <-4° and >+4°, respectively. The etiology and pathogenesis of adolescent idiopathic cervical kyphosis remain little understood. Weakness of the neck extensors can result in "dropped head syndrome", a rare disorder characterized by weakness of neck extensor muscles causing an inability to extend the neck and resulting in a chin-on-chest deformity. The purpose of this paper is to propose a possible mechanical cause leading to the kyphotic deformity. We hypothesize that weakness of the neck extensors could be the initiating factor for adolescent idiopathic cervical kyphosis.
颈椎后凸畸形可能是先天性的，也可能是由于椎板切除术、创伤后畸形、感染、神经肌肉疾病（如肌营养不良症）、运动神经元疾病（如肌萎缩侧索硬化症）、肿瘤和炎症（如强直性脊柱炎）引起的。此外，青少年特发性颈椎后凸畸形被定义为青少年患者的颈椎后凸畸形，没有任何先前描述的原因。由于文献中找不到“颈椎后凸”的标准值，许多报道的研究仅报告了一种主观分类，即“后凸、直或前凸”。但这种方法已被证明是不可靠的。Grob 等人将整体曲率的“直”定义为+4°至-4°，前凸和后凸分别定义为<-4°和>+4°。青少年特发性颈椎后凸畸形的病因和发病机制仍知之甚少。颈部伸肌的无力可导致“垂头综合征”，这是一种罕见的疾病，特征为颈部伸肌无力，导致无法伸展颈部，导致下巴贴近胸部的畸形。本文旨在提出导致后凸畸形的可能力学原因。我们假设颈部伸肌的无力可能是青少年特发性颈椎后凸畸形的起始因素。
