Anatomic bases of medical, radiological and surgical techniques Cervical uncinate process: an anatomic study for anterior decompression of the cervical spine J. Lu 1 , N.A. Ebraheim 1 , H. Yang 1 , M. Skie 1 and R.A. Yeasting 2 1 Departments of Orthopaedic Surgery and 2 Anatomy, Medical College of Ohio, 3065 Arlington Avenue, Toledo, Ohio 46614, USA Received March 17, 1997/ Accepted in final form March 27, 1998 Key words: Cervical spine -- Uncinate process -- Radiculopathy -- Decompression -- Anatomy Correspondence to: A. Ebraheim Abstract Morphometric evaluation of 54 dry cervical spines from C3 to C7 (a total of 270 cervical vertebrae) was performed to determine the bony boundaries of the uncinate process for resection of the uncinate process for access to posterolateral osteophytes or herniated disks at the time of anterior cervical diskectomy. The uncinate processes were significantly higher (p < 0.01) at the C4 - C6 levels (5.8 ± 1.1 mm to 6.1 ± 1.3 mm) than at the C3 or C7 levels. The distance between the medial and lateral margins of the base of the uncinate process was significantly smaller (p < 0.01) at the C3 level (4.9 ± 0.7 mm) than at the C7 level (6.3 ± 0.7 mm). The anteroposterior diameter of the medial margin of the uncinate process decreased gradually from the C5 (12.5 ± 1.5 mm) to C7 levels (11.6 ± 1.3 mm) (p < 0.05). The inter-uncinate distance widened from the C3 (19.2 ± 1.5 mm) to the C7 (24.6 ± 2.1 mm) levels (p < 0.01). The mid-anteroposterior diameter of vertebral body increased gradually from the C3 (14.7 ± 1.1 mm) to the C7 levels (16.1 ± 1.5 mm) (p < 0.01). The width of the vertebra increased gradually from C3 to C7 (from 19.2 ± 1.8 mm at C3 to 25.6 ± 2.0 mm at C7) (p < 0.01). Knowledge of all the aforementioned data may be helpful during anterolateral cervical uncosectomy or uncoforaminotomy. Anterolateral decompression of the cervical spine, i.e. removal of compressing osteophytes and/or disk fragments anterior to the nerve root, is commonly performed as a treatment for cervical radiculopathy or myeloradiculopathy [3-5, 7, 15, 16, 19-21]. The main cause of cervical spondylotic radiculopathy is that osteophytes project from the uncinate process, which results in narrowing of the intervertebral foramina. Osteophytes projecting from the uncinate process also disturb blood circulation through the radicular a., contributing to the spondylotic cervical myelopathy [2]. It is agreed that adequate nerve root decompression is critical for successful treatment of cervical radiculopathy [5, 7, 16, 20]. Anterolateral or anteromedial uncosectomy and uncoforaminotomy provide relief of the compromised nerve root and vertebral a. [10, 11]. However, anatomic study of the uncinate process relevant to anterior cervical decompression has not been well addressed in the literature. Understanding the quantitative anatomy of the cervical uncinate process not only improves the safety of anterior cervical spine surgery but also allows adequate decompression of the neural elements. To gain access to the osteophytes from the uncinate process, we investigated the anatomical boundaries of the uncinate process from C3 to C7 and provided guidelines for surgical resection of this process in cervical spondylosis. Material and methods