Singla Mukesh, Kandwal Pankaj, Malhotra Rashmi, Ansari Mohd S, Arora Rajnish K, Bisht Kanchan, Singh Brijendra
Anatomy, All India Institute of Medical Sciences, Rishikesh, IND.
Orthopaedics, All India Institute of Medical Sciences, Rishikesh, IND.
Cureus. 2023 Mar 9;15(3):e35949. doi: 10.7759/cureus.35949. eCollection 2023 Mar.
With the advent of pedicle screws and advanced instrumentation techniques, internal fixation and stabilization of upper cervical vertebrae are possible in fractures of an axis. However, the proximity of vertebral arteries (VAs) poses a unique challenge to surgeons during these procedures and can result in profound physical impairment to patients. Cadaveric studies contributing to fine anatomical details necessitate conducting such studies.
After receiving due ethical permission, this descriptive cross-sectional study was carried out on 10 cadavers in the department of Anatomy, All India Institute of Medical Science (AIIMS) Rishikesh. Twenty VAs were dissected along their course, and measurements of parameters related to the axis and atlas vertebra were noted.
The length of the pre-osseous segment related to the axis (VAX-1) on the right and left sides were from 3.8 to 14.5 mm (7.48±3.88 mm) and 4.46 to 10.5mm (6.94±2.01mm) respectively. The length of the osseous segment related to the axis (VAX-2) on the right side and left sides were from 6.82 to 31 mm (17.9±7.84mm) and 7.35 to 20 mm (15.6±4.53). The osseous segment of the VA related to the axis (VAX-2) shows genu (bend), which extends to a variable distance towards the midline. The mean distance of VA genu from the midline of the axis vertebral body on the right and left sides was 15.6mm and 17.5 mm, respectively. The percentage of superior articular facet (SAF) surface area of the axis occupied by the VA was 25-50% in nine and 50-75% in 11 cadavers, reflecting incomplete occupancy.
The study suggests that for instrumentation of the axis vertebra in the midline, the minimum distance between the genu of both sides of VA segments, related to an osseous segment of the axis (VAX-2) and medial extent of the VA groove of the atlas, should be considered as a safe zone to minimize inadvertent VA injury. During atlantoaxial fixation through a posterior approach in interarticular, pars, and pedicle screws, the surgical anatomy of the VA in relation to the osseous segment of the VA within the transverse process of the axis should be kept in mind to avoid inadvertent VA injury.
随着椎弓根螺钉和先进器械技术的出现，枢椎骨折时对上颈椎进行内固定和稳定成为可能。然而，椎动脉（VAs）的毗邻位置给外科医生在这些手术过程中带来了独特的挑战，并可能导致患者严重的身体损伤。有助于详细解剖细节的尸体研究有必要开展此类研究。
在获得适当的伦理许可后，这项描述性横断面研究在全印度医学科学研究所（AIIMS）瑞诗凯诗分校解剖学系的10具尸体上进行。沿着20条椎动脉的走行进行解剖，并记录与枢椎和寰椎相关参数的测量值。
右侧和左侧与枢椎相关的骨前节段（VAX-1）长度分别为3.8至14.5毫米（7.48±3.88毫米）和4.46至10.5毫米（6.94±2.01毫米）。右侧和左侧与枢椎相关的骨节段（VAX-2）长度分别为6.82至31毫米（17.9±7.84毫米）和7.35至20毫米（15.6±4.53）。与枢椎相关的椎动脉骨节段（VAX-2）呈膝状（弯曲），向中线延伸不同距离。右侧和左侧椎动脉膝部距枢椎椎体中线的平均距离分别为15.6毫米和17.5毫米。在9具尸体中，椎动脉占据枢椎上关节面（SAF）表面积的百分比为25%至50%，在11具尸体中为50%至75%，表明占据不完全。
该研究表明，对于枢椎中线的器械操作，与枢椎骨节段（VAX-2）相关的椎动脉节段两侧膝部之间的最小距离以及寰椎椎动脉沟的内侧范围应被视为安全区，以尽量减少意外的椎动脉损伤。在通过关节间、椎弓根和椎弓根螺钉的后路进行寰枢椎固定时，应牢记椎动脉在枢椎横突内与椎动脉骨节段相关的手术解剖结构，以避免意外的椎动脉损伤。
