gms | German Medical Science

Objective: Clipping of aneurysms is decreasing in neurosurgical routine due to novel therapeutic techniques e.g. coiling. Models for neurosurgical clip training are until now not evaluated completely. Aneurysm models in animals are existing in dogs, rabbits and pigs, whereas models in rats are rarely described. Aim of the study was the evaluation of three different aneurysm models in rats and there impact for neurosurgical clip training and training of intraoperative Doppler sonography.

Methods: 22 Whistar rats were operated on. 39 aneurysms were created surgically in three different locations: 14 A. carotis models (pure arterial type), 13 A. femoralis models (arteriovenous fistula type) and 12 A. iliaca models (venous sack type) were built and used for microdopplersonographic examination and clip training. Complete operative room surrounding was simulated with bipolar coagulation and suction. The rats were positioned under a skull model with a 4x4 cm trephination. After clipping with mini-clips (Asculap) aneurysms were examined histologically. Neck/dome ratio and volume was calculated.

Results: The three models showed different surgical difficulties. The fastest model was the femoralis model (95 : 37 min, time for resident in training), the most difficult model the iliaca model (164 : 55 min). Neck/dome ratio was 0,85±0,16 (carotis), 0,31±0,05 (femoralis) and 0,94±0,16 (iliaca). Complications during creation of aneurysms appear only in the iliaca type aneurysm in 5 cases. Ruptur of the created aneurysm in the region of the dome occurred in three cases and could be managed by clipping or suture. All aneurysms could be clipped several times through the skull model without suture insufficiencies at the neck. Histologic examination revealed technical details of suturing and microanatomy of aneurysms.

Conclusions: Microsurgical training could be enhanced by creation of aneurysm models in rats. These models could be used for clipping and dopplersonography with great educational effort.