Warnke Jan-Peter, Tschabitscher M, Thalwitzer J, Galzio R
Department of Neurosurgery, Paracelsus-Hospital Zwickau, Zwickau, Germany.
Cent Eur Neurosurg. 2009 Nov;70(4):207-10. doi: 10.1055/s-0028-1093354. Epub 2009 Nov 17.
Endoscopic procedures are becoming increasingly important for transnasal transsphenoidal approaches to the skull base and particularly for pituitary surgery. A persistent trigeminal artery (PTA) is rare. Its presence, if it goes unnoticed or if the surgeon is not aware of such a variant, may endanger the success of surgery.
During an endoscopic inspection using a supraorbital approach in a fresh cadaveric specimen in which the arteries had been injected with latex glue, the presence of an anomalous intracranial artery, suggestive for PTA, was disclosed. The specimen was then fixed and a CT scan with 3D reconstruction of the circle of Willis was done to evaluate the imaging of such an anatomical variation. Thereafter an endoscopic transsphenoidal approach to the pituitary fossa was performed, to verify the endoscopic anatomy.
The performed CT scan allowed visualization of the entire course of the anomalous vessel, confirming a PTA. During the endoscopic transsphenoidal approach, the presence of the vascular anomaly, altering the bony bulging of the internal carotid artery on the lateral side of the sphenoidal roof, was disclosed. The parasellar course of the PTA could be exposed by drilling the overhanging bone. The presence of the anatomical variant did not interfere with surgical manoeuvres and the procedure, simulating a transsphenoidal approach to the pituitary, could be safely completed.
Variants such as PTA are rare and routine preoperative imaging for pituitary procedures does not always include studies to detect this vascular anomaly. The occasional intraoperative detection of a PTA during an endoscopic transsphenoidal procedure can be managed; almost any surgical manipulation is possible and pituitary surgery can be successfully completed, provided the surgeon is aware of the possible existence of this variant and its irregular anatomical course. However, the presence of a PTA may have dramatic consequences if surgery is directed to the lateral parasellar region, as for intracavernous lesions; in these cases a complete neuroradiological study including MRI-angiography and possibly CT-angiography is advised.
内镜手术在经鼻蝶窦入路至颅底手术，尤其是垂体手术中变得越来越重要。永存三叉动脉（PTA）较为罕见。若其存在未被注意到或外科医生未意识到这种变异，可能会危及手术的成功。
在一具新鲜尸体标本上采用眶上入路进行内镜检查，该标本的动脉已注入乳胶胶水，发现了一条提示为PTA的异常颅内动脉。然后将标本固定，并进行 Willis 环的CT扫描及三维重建，以评估这种解剖变异的影像学表现。此后，进行了经蝶窦内镜入路至垂体窝的手术，以验证内镜解剖结构。
所进行的CT扫描能够显示异常血管的全程，证实为PTA。在经蝶窦内镜入路手术中，发现血管异常的存在改变了蝶骨嵴外侧颈内动脉的骨质隆起。通过磨除悬垂骨质可暴露PTA的鞍旁走行。这种解剖变异的存在并未干扰手术操作，模拟经蝶窦入路至垂体的手术能够安全完成。
PTA等变异较为罕见，垂体手术的常规术前影像学检查并不总是包括检测这种血管异常的研究。在内镜经蝶窦手术中偶尔术中发现PTA是可以处理的；只要外科医生意识到这种变异可能存在及其不规则的解剖走行，几乎任何手术操作都是可行的，垂体手术也能成功完成。然而，如果手术针对鞍旁外侧区域，如海绵窦内病变，PTA的存在可能会产生严重后果；在这些情况下，建议进行包括磁共振血管造影以及可能的CT血管造影在内的完整神经放射学检查。
