Humerus axial projection. New intraoperative radiological projection proposal for proximal humeral fractures treatment by intramedullary nailing

Abstract

Background: guaranteeing humeral proximal fracture stabilization by intramedullary nailing is essential to correctly position the nail in the humeral head, being careful that proximal screws reach pluriaxially epiphysis cortices without protruding into the joint. Objectives: conventional intraoperative fluoroscopic radiography is used to verify positioning of these parts from the antero-posterior and transthoracic views. We suggest to integrate projections with an axial view, modified with regard to those proposed by Bool-Obata or Velpeau. Methods: we performed a clinical observational study in which we tested the effectiveness of this new projection. The primary endpoint was to assess the feasibility of performing this new projection. We also monitored the need for additional time. The secondary endpoint was to assess the reliability of this new projection, monitoring in how many patients the screws were in joint and were not visible to the two standard projections. Results: twenty patients undergoing intramedullary nailing surgery for proximal humeral fractures were monitored. This new projection did not cause any invasion of the working field of the other operators. Its execution required on average additional 30 seconds. It showed that a screw was in a joint in 6 patients, which was not visible with AP and TT projections (p=0.005). Discussion: we verified that it was possible to check the correct positioning of the head screws while safeguarding higher bone density areas. After an adequate learning curve, this projection could actually integrate the previous projections, since it is necessary to study the relations of the screws with the cortex and any protrusions into the joint.