Increased Radiation but No Benefits in Pedicle Screw Accuracy With Navigation versus a Freehand Technique in Scoliosis Surgery.

BACKGROUND: The clinical value of pedicle screws in spinal deformity surgery is well known; however, screw insertion is demanding and sometimes associated with complications. Navigation systems based on intraoperatively obtained three-dimensional (3-D) images were developed to minimize pedicle screw misplacements. However, there is a lack of data confirming superiority of navigation above other techniques. There are also concerns regarding increased radiation used during the procedure. QUESTIONS/PURPOSES: The purposes of this study were (1) to compare accuracy of the two methods of pedicle screws placement: intraoperative 3-D image navigation versus a freehand technique in patients with idiopathic scoliosis; and (2) to assess the radiation dose received by patients with both methods. METHODS: Between 2014 and 2016, 49 patients underwent posterior spinal fusion with all pedicle screw constructs for idiopathic scoliosis performed by two surgeons. The study design involved alternating the use of the freehand technique and navigation to position pedicle screws in consecutive patients, forming groups of 27 patients with 451 navigated screws and 22 patients with 384 screws positioned freehand. The two groups did not differ in age, sex, or magnitude of deformity. Two observers not involved in the treatment evaluated the position of the screws. The pedicle breach was assessed on intraoperatively obtained 3-D O-arm® scans according to a grading system: Grade 0 = no pedicle wall violation; Grade 1 = perforation ≤ 2 mm; Grade 2 = 2 to 4 mm; and Grade 3 = perforation > 4 mm. Grades 0 and 1 were considered properly positioned and Grades 2 and 3 represented malposition. RESULTS: In terms of accuracy, we found no differences, with the numbers available, between the freehand and navigated groups in terms of the proportion of screws that were properly positioned (96% freehand and 96% in the navigation group, respectively; p = 0.518). Grade 3 pedicle screws were observed only in the freehand group and were all located in the upper thoracic spine. Patients undergoing navigated pedicle screw placement received a greater mean radiation dose than those whose screws were placed freehand (1071 ± 447 mGy-cm versus 391 ± 53 mGy-cm; mean difference, 680 mGy-cm; 95% confidence interval, 217-2053 mGy-cm; p < 0.001). CONCLUSIONS: In patients with moderate idiopathic scoliosis undergoing primary surgery, we did not observe benefits of pedicle screw placement with CT-based navigation, but the patients experienced greater exposure to radiation. LEVEL OF EVIDENCE: Level III, therapeutic study.

The impact of direct vertebral rotation (DVR) on radiographic outcome in surgical correction of idiopathic scoliosis.

INTRODUCTION: Recent developments of spinal instruments allow to address nearly all components of idiopathic scoliosis. Direct vertebral rotation (DVR) maneuver was introduced to correct apical axial vertebral rotation. It is however still not well established how efficiently DVR affects results of scoliosis correction. The object of the study was to evaluate en bloc apical vertebral rotation (DVR) and its impact on coronal and sagittal correction of the spine in patients undergoing surgical scoliosis treatment. MATERIALS AND METHODS: Thirty-six consecutive patients who underwent posterior spinal fusion with pedicle screws only constructs for idiopathic scoliosis. Fifteen patients (20 curves) were corrected by rod derotation only and 21 patients (26 curves) had both rod derotation and DVR. Curve measurements were performed on x-rays obtained before and postoperatively-coronal curves, kyphosis (T2-T12, T5-T12). Spine flexibility was assessed on prone bending x-rays. Apical axial rotation was determined on CT scans obtained intraoperatively and postoperatively. Rotation angle (RAsag) was measured according to Aaro and Dahlborn. RESULTS: We observed reduction of RAsag in all patients; however, in DVR group, decrease was greater, by 31.8% comparing to non-DVR group, by 8.6% (p = 0.0003). Mean coronal correction in DVR group was 68.8% and in rod derotation group without DVR 55% (p = 0.002). No significant correlation was found between degree of derotation obtained and coronal correction. In DVR group T2-T12 kyphosis has increased in 28 (65%) patients whereas in non-DVR group in 31 (69%) cases. Mean value of T2-T12 kyphosis growth was 16.7% in DVR and 22.1% in non-DVR group. These differences however did not occur statistically significant. CONCLUSIONS: Direct vertebral rotation (DVR) maneuver reduces significantly apical rotation of the spine, enhances ability of coronal correction, and it does not reduce thoracic kyphosis.

A minimal soft tissue damage approach of spondylolysis repair in athletes: preliminary report.

PURPOSE AND HYPOTHESIS: Both spondylolysis and spondylolisthesis come in second place in the causes of pain among athletes. Treatment options include both conservative management and different operative methods. Athletes and adolescents are groups where the priority is to protect tissues from perioperative damage. OBJECTIVE: We present our modification of the Buck's, direct pars repair method, which we believe offers maximum protection of tissues. We used the modified surgical method in young, competitive athletes, in whom non-surgical treatment was not effective. METHOD: Eight pars defects in five patients were treated using suggested method. All of them were young males (aged between 13 and 18 years), who practice soccer professionally. We use modified method of direct repair pars through the cannulated screw fixation, first proposed by Buck. Preoperative preparation consists of proper analysis of computer tomography images in multiplanar reconstruction mode: measuring screw length, measurement of inclination angle of the optimal screw trajectory in the frontal and sagittal plane. During the operation, the wire proper direction is performed by usage of the predetermined angles. Starting point for guide wire was also changed to the lower end of the facet. The fusion takes place with a screw of 3 mm diameter. After the operation patient need to use thoracolumbar spinal orthosis as a primary immobilization for 6 weeks and appropriate rehabilitation for another 6 weeks. We used these methods in eight pars fixations. RESULTS: All of the patients were painless in first week after surgery. All of them underwent total rehabilitation programme and returned to sport. CONCLUSIONS: Direct pars repair using Buck's method with proposed modification, including adequate radiographic preparation, the use of a thin cannulated screw and changing the point of screw entry, allows precise and safe screw placement, regardless of the size of the bone at the defect site.