제 1 천추체에 전측방으로 나사못 고정시의 해부학적 안전지역에 대한 재평가
Anatomical Safe Zone of Sacral Ala for Ventrolateral Sacral(S1) Screw Placement : Re-evaluation of Its Effectiveness
소속 상세정보
도재원/Jae Won Doh
EdwardC.Benzel/이경석/배학은/윤일규/최순관/변박장/Edward C. Benzol/Kyung Suck Lee/Hak Eun Bae/Il Kyu Yoon/Soon Kwan Choi/Park Jang Byun
KMID : 0359819980270030291
Abstract
결론
1) 천골날개뼈를 안전하게 관통하는 나사못의 안전각도가 33.5°±9.3였으나 안전각도의 범
위가 최저 20°에서 최고 50°까지로 편차가 심하여 실제 수술시에 이 안전각도를 일률적으
로 사용하기는 어려우며 수술전에 모든 환자에게 CT를 하여 나사못의 각도와 깊이를 개별
화하여 적용함이 좋을 것으로 사료된다
2) 안전지역을 관통한 K-wire의 끝에서부터 요천골신경총, 천장관절까지의 거리는 각각
6.8mm±1(6∼9.5), 4.8mm±1(4∼7.5)로 거리가 짧았다. 또한 천골날개뼈의 앞쪽 표현으로부
터 내장골정맥까지의 거리가 2.1mm±1.7(0∼5)였고, 요천골신경총까지는 0mm로 모두 천골
표면에 붙어 있었다. 이러한 구조물들은 나사못고정시에 다칠 위험이 있으므로 주의를 요한
다
3) 본 연구 결과로 볼 때 천골날개 앞쪽의 해부학적 안전 지역은 나사못고정시에 절대 안전
하지 않았다. 그러므로 천골날개뼈를 관통하는 나사못고정을 할 때에는 합병증을 막기 위해
서 수술중에 나사못의 각도와 길이를 정확히 측정할 있는 척추정위기구의 도움이 필요할 것
으로 사료된다. 이러한 기구의 이용이 불가능하면 전방고정술이나 갈고리(hook)고정술등 다
른 수술방법을 고려할 필요가 있을 것으로 사료된다
#초록#
Among the various sacral fixation technique used to enhance the strength of fixation.
S1 screw placement in the sacrum is the most common method. Ventrolateral S1 screw
placement through the sacral ala has been used alone or in combination with a
medially-directed screw in the S1 pedicle to enhance pull-out resistance. Although the
anatomical safe zone was identified, there is a risk of neurovascular injury particularly
when the enhancement of fixation strength requires bicortical purchase. The purpose of
this cadaver study is to re-evaluate the previous anatomical safe zone with using an S1
screw laterally directed toward the sacral ala. After dissecting the lateral safe xone of
sacral ala in 12 human cadavers. K-wires were intentionally inserted deep into this
zone. Each 'safe' angle to the center of the safe zone was measured and the degree of
risk to neurovascular structures was recorded on the basis of the distance in millimeters
from the tips of the penetrating K-wires.
The results are as follows ; the mean safe angle to the center of the anatomical safe
zone was 33.5°±9.3(20-50). Between 20 and 50 degrees, the range of safe angle was
too wide. The distance between the tip of the K-wire and the sacroiliac joint,
lumbosacral trunk, obturator nerve was 4.8mm±1(4-7.5), 6.8mm±196-9.5) and 6.8mm±
3.2(0-10) respectively, while the anterior height between sacral cortex and lumbosacral
trunk, internal iliac vein was 0mm and 2.1mm±1.8(0-5) respectively. In 29% of cases,
the iliolumbar artery, the first branch of the internal iliac artery, abnormally crossed the
middle of the safe zone. The sacroiliac joint, lumbosacral trunk, internal iliac vein and
iliolumbar artery were at risk from laterally-directed S1 screws.
The study shows that bicortical placement of S1 screws into the sacral presents
unnecessary risks to neurovascular structures. It is concluded that the previous
anatomical safe zone for bicoritcal S1 screw placement into the sacral ala was not
surgically safe, and when lumbosacral fixation surgery is planned, operative techniques
other than bicortical screw placement should be considered.
키워드
Sacral screw fixation; Ventrolateral direction; Bicortical purchase; Anatomical safe zone.;
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