Evidence that L5 transverse process fracture indicates pelvic instability is insufficient and controversial. Because of unstable pelvis fractures have high mortality rate, they require urgent treatment and good follow-up. The lumbar region is also affected by high-energy traumas in the pelvis region, which causes damage to the muscles and ligamentous structures that adhere to the lumbar transverse process. For this reason, L5 transverse process fracture is thought to be an indicator showing pelvic instability. However, our study shows that this is not like that. This study was carried out in order to investigate the effect of L5 transvers process fracture on pelvic instability and lack of sufficient data in the literature.

Between 2017–2020, 86 Patient who were hospitalized and treated with a diagnosis of pelvic fracture were retrospectively studied in our clinic. Pelvic X-Ray and tomography was taken pre-op for all patient. Demographic features, pre-op and post-op hemoglobin counts, how many units of blood transfusion needed in total, fixation method, surgical intervention, presence of additional injury, mechanism of injury for all patient were analyzed and the patients were categorized by investigating L5 transvers process fracture in their tomography. Fractures of patients were classified according toTyle classification. The patients were divided into two main groups as who stabil and unstabil pelvic fractures and L5 transvers process fracture and without.

On stabil pelvic fractures and unstabil pelvic fractures, in term of instability effects of L5 transvers process fractures and those without were investigated. Also, changes in preop and post op hemoglaobin counts were investigated in pelvis with and without L5 transvers process fractures. With these, in terms of blood transfusion need the patients were evaluated whether there was a difference between those with L5 transvers process fractures and who did not. Again, whether the blood transfusion was statistically different in stable and unstable pelvis fractures was among the parameters looked at. In statistical analysis, no correlation was found between pelvic instability and L5 transvers process fracture. (p=0,933) No statistically significant difference was found in the evalution of blood transfusion between those with and without L5 transvers process fractures. (P=0,409)When the same parameter was evaluated in terms of stability and instability of the pelvis, it was seen that stability did not significantly affect the need for blood transfusion. (P=0,989) Pre-op and post-op hemoglobin changes of the patients who with L5 transvers process fracture and without were also analized. İn the analysis performed, there was no significant difference in patients with and without L5 transvers process fractures on pre-op and post-op hemoglobin values. (p=0.771/p=0.118)However, Postoperative hemoglobin values were significanly lower in patient with L5 transvers process fracture compared to preopetative hemoglobin values. (p=0.001)

L5 transvers process fracture is not a parameter to showing pelvic instability. Stabil and unstabil fractures did not change the need for blood transfusion. The literatüre still needs much more study on this topic.