Kasab Reyhan, Yilmazlar Selcuk, Altunyuva Oguz, Fedakar Recep
Bursa Uludag University School of Medicine, Department of Neurosurgery, Bursa, Turkey.
Bursa Uludag University School of Medicine, Department of Neurosurgery, Bursa, Turkey.
Neurocirugia (Engl Ed). 2025 Jan-Feb;36(1):39-46. doi: 10.1016/j.neucie.2024.09.005. Epub 2024 Oct 2.
The sellar region is an area in the base of the skull that is among the most common sites for tumors of the central nervous system. Surgical interventions are currently performed via different routes. While the optic chiasm occupies its expected position in 70% of the population, it can deviate from this position. In such cases, surgery involving this region becomes more difficult as the known surgical routes are narrowed. Advance awareness of these variations can help surgeons to identify the optimal route for safe surgical intervention in the sellar region. By performing simple measurements of both the lengths of the optic nerves and the angle between them, a surgeon can predict the location of the chiasm.
Twenty specimens collected from autopsies performed at Bursa Forensic Medicine İnstitute were examined to determine the optic chiasm types and the relationships between the surrounding subchiasmal structures.
Among the 20 specimens, we found two prefixed (10%), 10 normo-fixed (50%), and eight postfixed chiasms (40%). The mean interoptic angle was 81.03 (±17.41)⁰. Prefixed chiasms had angles in the range 115.36°-124.76 ° (mean 120.06 [±6.65]⁰), normo-fixed chiasm angles were between 83.11° and 97.53 ° (mean 86.07 [±6.73]⁰), and postfixed chiasms ranged between 53.01 ° and 78.71 ° (mean 69.20 [±9.13]⁰). The length of the right optic nerve ranged between 6.95 and 13.83 mm (mean 10.25 [±1.81] mm), and the length of the left between 7.25 and 12.51 mm (mean 10.40 [±1.47] mm). Obtuse angles indicated that the chiasm was prefixed, and acute angles were indicative of a postfixed chiasm. There was a strong negative correlation between optic nerve lengths and the interoptic angle; thus, as the length of the nerves increases, the interoptic angle becomes more acute.
We have proposed a simple measurement of the optic nerve lengths and the angle between them to predict the relative location of the OC, which can be done easily on MRI.
鞍区是颅底的一个区域，是中枢神经系统肿瘤最常见的部位之一。目前通过不同途径进行手术干预。虽然70%的人群中视交叉处于预期位置，但它可能偏离该位置。在这种情况下，由于已知的手术路径变窄，涉及该区域的手术变得更加困难。提前了解这些变异有助于外科医生确定鞍区安全手术干预的最佳路径。通过对视神经长度及其之间角度进行简单测量，外科医生可以预测视交叉的位置。
检查了从布尔萨法医学研究所尸检中收集的20个标本，以确定视交叉类型及其周围视交叉下结构之间的关系。
在20个标本中，我们发现2个前置型（10%）、10个正常固定型（50%）和8个后置型视交叉（40%）。平均视交叉角为81.03（±17.41）°。前置型视交叉的角度范围为115.36°至124.76°（平均120.06 [±6.65]°），正常固定型视交叉角度在83.11°至97.53°之间（平均86.07 [±6.73]°），后置型视交叉在53.01°至78.71°之间（平均69.20 [±9.13]°）。右侧视神经长度在6.95至13.83毫米之间（平均10.25 [±1.81]毫米），左侧视神经长度在7.25至12.51毫米之间（平均10.40 [±1.47]毫米）。钝角表明视交叉是前置型，锐角表明视交叉是后置型。视神经长度与视交叉角之间存在很强的负相关；因此，随着神经长度增加，视交叉角变得更尖锐。
我们提出了对视神经长度及其之间角度进行简单测量以预测视交叉相对位置的方法，这可以在磁共振成像（MRI）上轻松完成。
