Retrospective analysis of screw positions in spinal cases in which transpedicular screw is fixed

Purpose: In our study, the purpose was to retrospectively analyze the screw positions of the patients between the ages 14-81 to whom operative transpedicular screw fixation was applied in elective and emergency cases according to various diagnoses, and to decrease the complications which developed as a result of screw malpositions. Material and Method: In our retrospective study, 100 cases were analyzed in total which were treated with the diagnoses of stenosis (11 cases), spondylolisthesis (17 cases), trauma (45 cases), lombar disc hernia (2 cases), spinal tumor (18 cases) and spinal infection (7 cases) between January 2012 - September 2016 in the Brain and Nerve Surgery Clinics of Çukurova University Medical Faculty. The cases were evaluated within 72 hours postoperatively with frontal, rear and lateral x-rays and computed tomographies. The ages, genders, the numbers of screws placed in each patient, postoperative deficits, emergence of postoperative complications (wound site infection, dura damage and cerebrospinal fluid fistula, the implementation of wound debridement in consequence of late wound healing), the numbers of screws fixed at each level, the levels of malpositioned screws and the number of revision surgeries among these were determined. The data obtained were analyzed with SPSS 2.0 for Windows. Findings: 610 (88,15%) of 692 fixed transpedicular screws were evaluated as normal. 82 (11,85%) of the screws were evaluated as malpositioned and 5 of these (6,10%) were repositioned by revisioning. Anterior perforation was determined to be 4 (0,66%), medial perforation to be 39 (6,39%), lateral perforation to be 38 (6,23%) superior perforation to be 0 (0%) and inferior perforation to be 1 (0,16%). Of the 39 screws which were medially malpositioned, 24 (61,54%) were found to be at the thoracic level and 15 (38,46%) were found to be at the lumbosacral level. It was also observed that, of the 38 screws which were laterally malpositioned, 35 (92,11%) were at the thoracic level and 3 (7,89%) were at the lumbosacral level. Of the 38 laterally malpositioned screws, 35 (92,11%) were at the thoracic level while 3 (7,89%) were at the lumbosacral area. Of the 82 malpositioned screws, 24,4% (20 screws) were found to be Grade 1 (0-2 mm), 53,7% (44 screws) were Grade 2 (2-4 mm), and 15,9% (13 screws) were Grade 3 (more than 4 mm). Result: A well-established anatomical and biomechanical knowledge is required to avoid complications. The experience of a surgeon in screw fixation increases the rate of accurate screw placement. It is found out that intraoperative CT imaging techniques and navigation-guided transpedicular screw fixation give better results compared to conventional techniques. Key Words: Transpedicular screw, Malpositioned screw, Spinal instrumentation