Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, Florida 33606, USA.
J Neurosurg Spine. 2011 Sep;15(3):328-31. doi: 10.3171/2011.5.SPINE10778. Epub 2011 Jun 3.
Occipital condyle screws serve as an alternative fixation point in occipital-cervical fusion. Their placement requires a thorough understanding of the anatomy of the occipital condyles and associated structures. This study is a CT-based morphometric analysis of occipital condyles as related to occipital condyle-cervical fusion.
A total of 170 patients were examined with CT scans of the craniocervical junction at a single institution, for a total of 340 occipital condyles, between March 6, 2006, and July 30, 2006. All CT scans were negative for traumatic, degenerative, and neoplastic pathological entities. Condylar anteroposterior (AP) length, transverse width, height, projected screw angle, and projected screw lengths were measured on an EBW Portal 2.5 CT Viewer Workstation (Philips Electronics). The longest axis in the AP orientation of the occipital condyle was accepted as the length. The transverse width was a line perpendicular to the midpoint of the long axis. The height was measured in the coronal projection that had the thickest craniocaudal portion of the condyle. The screw trajectory started 5 mm lateral to the medial edge of the condyle and a line was directed anteromedially in the longest axis. The angle was measured relative to the sagittal midline. The screw length was measured from the outer cortex of the posterior wall to the outer cortex of the anterior wall.
The mean ± SD values for occipital condyle measurements were as follows: AP length was 22.38 ± 2.19 mm (range 14.7-27.6 mm); width was 11.18 ± 1.44 mm (range 7.4-19.0 mm); height was 9.92 ± 1.30 mm (range 5.1-14.3 mm); screw angle was 20.30° ± 4.89° (range 8.0°-34.0°); and screw length was 20.30 ± 2.24 mm (range 13.0-27.6 mm).
These measurements correlate with previous cadaveric and radiographic studies of the occipital condyle, and emphasize the role of preoperative planning for the feasibility of placement of an occipital condyle screw.
枕骨髁螺钉可作为枕颈融合的另一种固定点。其置钉位置需要对枕骨髁及其相关结构的解剖有深入的了解。本研究是对枕骨髁-颈椎融合术相关的枕骨髁进行基于 CT 的形态计量分析。
2006 年 3 月 6 日至 2006 年 7 月 30 日，在一家医疗机构对 170 例颅颈交界区 CT 扫描患者的 340 个枕骨髁进行了检查。所有 CT 扫描均未发现创伤、退行性和肿瘤性病变。在 EBW Portal 2.5 CT 观察工作站（飞利浦电子）上测量髁突的前后径（AP）长度、横径、高度、拟置钉角度和拟置钉长度。枕骨髁在 AP 方向的最长轴被接受为长度。横径为通过长轴中点的垂直线。在具有髁突最厚颅尾部分的冠状投影中测量高度。螺钉轨迹始于距髁突内侧缘 5mm 处，一条线在内前方向长轴上定向。角度相对于矢状中线测量。螺钉长度从后侧壁的外皮质测量到前侧壁的外皮质。
枕骨髁测量的平均值±标准差如下：AP 长度为 22.38±2.19mm（范围 14.7-27.6mm）；宽度为 11.18±1.44mm（范围 7.4-19.0mm）；高度为 9.92±1.30mm（范围 5.1-14.3mm）；螺钉角度为 20.30°±4.89°（范围 8.0°-34.0°）；螺钉长度为 20.30±2.24mm（范围 13.0-27.6mm）。
这些测量值与先前对枕骨髁的尸体和影像学研究相关，强调了术前规划对枕骨髁螺钉置钉可行性的作用。
