[Surgical Correction of Scoliosis: Does Intraoperative CT Navigation Prolong Operative Time?] / Operacní korekce skoliózy: prodluzuje peroperacní CT navigace trvání operace?

PURPOSE OF THE STUDY The aim of the study was to compare the duration of corrective surgery for scoliosis in relation to the intra-operative use of either fluoroscopic or CT navigation. MATERIAL AND METHODS The indication for surgery was adolescent idiopathic scoliosis in younger patients and degenerative scoliosis in middleage or elderly patients. In a retrospective study, treatment outcomes in 43 consecutive patients operated on between April 2011 and April 2014 were compared. Only patients undergoing surgical correction of five or more spinal segments (fixation of six and more vertebrae) were included. RESULTS Transpedicular screw fixation of six to 13 vertebrae was performed under C-arm fluoroscopy guidance in 22 patients, and transpedicular screws were inserted in six to 14 vertebrae using the O-arm imaging system in 21 patients. A total of 246 screws were placed using the C-arm system and 340 screws were inserted using the O-arm system (p < 0.001). The procedures with use of the O-arm system were more complicated and required an average operative time longer by 48% (measured from the first skin incision to the completion of skin suture). However, the mean time needed for one screw placement (the sum of all surgical procedures with the use of a navigation technique divided by the number of screws placed using this technique) was the same in both techniques (19 min). DISCUSSION With good teamwork (surgeons, anaesthesiologists and a radiologist attending to the O-arm system), the time required to obtain one intra-operative CT scan is 3 to 5 minutes. The study showed that the mean time for placement of one screw was identical in both techniques although the average operative time was longer in surgery with O-arm navigation. The 19- minute interval was not the real placement time per screw. It was the sum of all operative times of surgical procedures (from first incision to suture completion including the whole approach within the range of planned stabilization) which used the same navigation technique divided by the number of all screws inserted during the procedures. The longer average operative time in procedures using O-arm navigation was not related to taking intra-operative O-arm scans. The authors consider surgery with an O-arm imaging system to be a safer procedure and use it currently in surgical correction of scoliosis. CONCLUSIONS The study focused on the length of surgery to correct scoliosis performed using either conventional fluoroscopy (C-arm) or intra-operative CT scanning (O-arm) showed that the mean placement time for one screw was identical in both imaging techniques when six or more vertebrae were stabilised. The use of intra-operative CT navigation did not make the surgery longer, and the higher number of inserted screws provides evidence that this technique is safer and allows us to achieve good stability of the correction procedure. Key words: virtual CT guidance, O-arm, scoliosis, transpedicular screw.

[Intraoperative CT navigation in spinal and pelvic surgery: initial experience]. / Peroperacní CT navigace u operací pátere a pánve: první zkusenosti.

INTRODUCTION: The authors describe their first experience with virtually navigated pelvic and spine screws based on perioperative CT navigation. MATERIAL AND METHODS: From 22 October 2012 (launching the device) to 9 January 2013, a total of 15 CT-navigated pelvic and spine operations were performed in 14 patients. Nerve root compression, scoliosis, vertebral fracture and spondylodiscitis were the indications for spine procedures; B-type and C-type fractures according to the AO classification were the indications in pelvic surgical procedures. The preparation and the course of the procedures were in accordance with current standards and recommendations in all the cases. Perioperative navigation and subsequent examination of the screw trajectory were performed via O-arm imaging system (Medtronic Navigation, Louisville, Colorado) instead of the standard C-arm fluoroscopy. RESULTS: A total of 73 screws were inserted (60 transpedicular screws into cervical, thoracic and lumbar vertebrae, 9 iliosacral screws into the first sacral vertebra and 4 pubic screws). Only one of the pubic screws (1.4% of all screws) was found malpositioned at the subsequent perioperative examination and was extracted immediately and replaced. Further complications were not observed and none of the procedures had to be converted into a standard fluoroscopy guided operation. CONCLUSION: A short but intensive experience with perioperative CT navigation allows us to state: 1. CT navigation shortens the operating time and minimalizes the risk of screw malposition in multiple screw spine procedures; 2. CT navigation improves the introduction of iliosacral and pubic screws in pelvic fixations; 3. there is virtually no radiation load to the staff using the CT navigation; 4. mastering this technique will allow a wider use of miniinvasive screw insertion in the pelvis and other regions where minimal dislocation will enable miniinvasive internal fixation.