Individuazione di corridoi di sicurezza anatomici sulla faccia laterale di corpi vertebrali del tratto toracico e lombare nel cane. Valutazione preliminare finalizzata alla stabilizzazione chirurgica del rachide in seguito a trauma.

Abstract

Objective To define lateral safe implantation corridors in canine thoraco-lumbar vertebral bodies (T6-L7) are perfomed simulations on cadavers followed by computed tomography (CT); Materials and Methods CT images of spinal column of twenty dog were used to define lateral safe corridors in cross section plane. The angle allowing the highest amount of bone purchase with safe margins for bicortical implants defined the optimal corridor. The corridors were charaterized by: insertion points with maximal width (W) and length (L), optimum angle (α); maximum (β) and minimum (γ) safe angles (from the midsagittal plane). The present study was carried out on 13 canine cadavers performing vertebrae trepanation. The collected data were entered into spreadsheets (Microsoft Excel2011 for Mac ®) before being imported into a program for statistical analysis (JMP ® v. 8.0.2 SAS Institute, Inc.). Continuous variables were compared using analysis of variance (ANOVA) of derWaerden van, and when a significant difference was detected, post hoc using Tukey HSD test. Results Insertion points were the vertebro-costal joint and the base of transverse process for thoracic and lumbar vertebrae, respectively. Optimum angle (α) was 90°. A decrease of safe gap for the last three lumbar vertebrae was detected. A smaller angle (β) for the last two vertebrae then the others considered in the study was found. A smaller angle (γ) for the L7 then the last thoracic vertebra and the last four lumbar vertebrae was observed. Conclusion A good safe gap and anchoring for synthetic materials (screw/nails), for the section of the dog's spine investigated in the study, was detected employing the lateral corridors. The lateral approach promote an easy screws orientation along the axis and the position preferred, such us a good visualization of the vertebral bodies allowing a right placement through a bicortical anchorage.