Veterinary session

In recent years, thoracolumbar surgeries have gained increasingly high importance in veterinary surgery as they can effectively treat a wide range of conditions affecting the spinal column in the thoracal and lumbar regions. Seamless anatomical knowledge is therefore essential for the surgeon to evaluate the various amount of anatomical surgical landmarks during the surgery, which can help to find the accurate site of the lesion. These landmarks are important anatomical features of the spinal structures that can be easily and safely evaluated in a reproducible manner intraoperatively.

In human and veterinary medicine, various studies have been performed to reduce the occurrence of wrong-site spinal surgery. A surgery at an incorrect level may have several negative outcomes for the patient and may increase the surgical time.

This descriptive study of nine dog cadavers aims to research the anatomical surgical landmarks for the thoracolumbar region between the eleventh thoracal vertebra and the first lumbar vertebra. Both bony and soft tissue landmarks are described which can be used for orientation preoperatively and intraoperatively to possibly reduce the use of radiological devices, the amount of radiation exposure and surgical and anaesthesia time.

The cadavers were dissected in ventral recumbency at the thoracolumbar region. Over the course of the dissection, the landmarks were dissected including the assessment of the positions of the processi mammillares, the relation of L6 and L7 to the intercristal line, along with the insertion points of the musculus spinalis et semispinalis thoracis et cervicis.

The dissection showed the consistency of various landmarks. The bony landmarks include the processus spinosus of the anticlinal vertebra, the difference between the processus transversus of L1 and the last rib and the intercristal line, which passes through the interspinous space of L6 and L7. The use of the processi mammillares could likewise provide valuable information as they are most accessible at Th13 and L1. For surgeries around Th11, assessing the facet joint's orientation is advisable. Soft tissue landmarks, which have been consistent throughout all nine dogs include the insertion of the musculus spinalis et semispinalis thoracis et cervicis into the fascia lumbodorsalis at Th11. Additionally, the evaluation of the position of the inserting tendons could be used as well as the insertion of the musculus longissimus lumborum into the accessory process of L1.

Anatomical surgical landmarks should be evaluated preoperatively as well as intraoperatively to reduce the risk of wrong-site spinal surgery and potentially reduce surgical time. Proper preoperative preparation for the surgery should be done before surgery to avoid wrong-site surgeries and associated problems.