No abstract available.
Prolapse ; Tropism ; Zygapophyseal Joint

Methods: We analyzed the radiological records of 44 consecutive patients with scoliosis and syringomyelia. Of these 44 patients, 13 had IS, 12 had CM1, and 19 had congenital scoliosis. The radiographs were evaluated to determine the curve magnitude, sagittal alignment, side of convexity, and type of vertebral anomaly, if any. T1- and T2-weighted magnetic resonance imaging of the whole spine was analyzed to determine the presence of craniovertebral anomalies, syrinx length, syrinx diameter, and syrinx-cord ratio (SCR). Results: The frequency of left convex curves was 26.1%, with no significant differences across the three groups. The mean length of the syrinx was 7.2±4.9 vertebral levels, and the mean SCR was 0.39±0.2. The mean syrinx length was significantly higher in patients with CM1 and IS, compared to patients with congenital scoliosis. The mean SCR was highest in patients with CM1. In congenital scoliosis, syringomyelia was seen most frequently in patients with a failure of formation, and 63.2% had concomitant cord anomalies. Conclusions Syrinxes were smaller in size and length in patients with congenital scoliosis, and are distinct from those seen in IS and CM1.

STUDY DESIGN: Cross-sectional study. PURPOSE: To evaluate the association between zygapophyseal joint angle (ZJA), facet tropism (FT), and lumbar intervertebral disc prolapse (IVDP). OVERVIEW OF LITERATURE: Several studies have shown that FT increases the risk of IVDP and have postulated that a more sagittally oriented zygapophyseal joint provides less mechanical resistance to axial torque, thereby exerting excessive rotational strain on the intervertebral disc, resulting in an annular tear. In contrast, other studies have found no definitive association between FT and IVDP. Therefore, conclusive evidence regarding the role of FT in the pathogenesis of disc prolapse is currently lacking. METHODS: Magnetic resonance imaging scans of 426 patients with single-level lumbar IVDP were analyzed. Right and left ZJAs of the lumbar segments were measured on axial sections. The frequency and severity of FT were determined by calculating the absolute difference between the right and left ZJAs. Patients without IVDP at L4–L5 and L5–S1 served as controls for those with IVDP at L4–L5 and L5–S1, respectively. Chi-square test and t-test were used to compare the severity and frequency of FT between patients with and without IVDP. The receiver operating characteristic analysis was performed to determine the critical FT values that were predictive of IVDP. RESULTS: Patients with IVDP exhibited a higher frequency (L4–L5: 47% vs. 15.08%; L5–S1: 39.62% vs. 22.69%; p=0.001) and severity (L4–L5: 7.85°±3.5° vs. 4.05°±2.62°; L5–S1: 7.30°±3.07° vs. 4.82°±3.29°; p < 0.001) of FT than those without IVDP. Critical FT values of 5.7° at L4–L5 and 6° at L5–S1 increased the likelihood of IVDP by a factor of 2.89 and 1.75, respectively. CONCLUSIONS: Our results confirm the existence of a significant association between lumbar IVDP and FT; however, a causal relationship could not be ascertained.
Cross-Sectional Studies ; Humans ; Intervertebral Disc ; Magnetic Resonance Imaging ; Prolapse ; ROC Curve ; Tears ; Torque ; Tropism ; Zygapophyseal Joint

Methods: In this prospective study, a total of 1,120 pedicle screws were placed in the freehand group (n=175), 1,250 in the fluoroscopyassisted group (n=172), and 1,225 in the robotic-assisted group (n=180). Surgical parameters and screw accuracy were analyzed between the three groups. The preoperative plan overlapped with the postoperative O-arm scan to determine if the screws were executed as planned. Results: The frequency of clinically acceptable screw placement (Gertzbein-Robbins grades A and B) in the freehand, fluoroscopy-assisted, and robotic-assisted groups were 97.7%, 98.6%, and 99.34%, respectively. With robotic assistance, an experience-neutralizing effect implied that surgeons with varying levels of experience achieved comparable pedicle screw accuracy, blood loss, O-arm time, robot time, and time per screw. No significant difference in these parameters was found between surgeries commencing before and after 2 PM. No significant differences were noted between the planned and executed screw trajectories in the robotic-assisted group irrespective of surgical experience. Conclusions The third-generation robotic-assisted pedicle screw placement system used in conjunction with intraoperative threedimensional O-arm imaging consistently demonstrates safe and accurate screw placement with an experience-neutralizing effect.

Methods: In this prospective study, a total of 1,120 pedicle screws were placed in the freehand group (n=175), 1,250 in the fluoroscopyassisted group (n=172), and 1,225 in the robotic-assisted group (n=180). Surgical parameters and screw accuracy were analyzed between the three groups. The preoperative plan overlapped with the postoperative O-arm scan to determine if the screws were executed as planned. Results: The frequency of clinically acceptable screw placement (Gertzbein-Robbins grades A and B) in the freehand, fluoroscopy-assisted, and robotic-assisted groups were 97.7%, 98.6%, and 99.34%, respectively. With robotic assistance, an experience-neutralizing effect implied that surgeons with varying levels of experience achieved comparable pedicle screw accuracy, blood loss, O-arm time, robot time, and time per screw. No significant difference in these parameters was found between surgeries commencing before and after 2 PM. No significant differences were noted between the planned and executed screw trajectories in the robotic-assisted group irrespective of surgical experience. Conclusions The third-generation robotic-assisted pedicle screw placement system used in conjunction with intraoperative threedimensional O-arm imaging consistently demonstrates safe and accurate screw placement with an experience-neutralizing effect.

Methods: In this prospective study, a total of 1,120 pedicle screws were placed in the freehand group (n=175), 1,250 in the fluoroscopyassisted group (n=172), and 1,225 in the robotic-assisted group (n=180). Surgical parameters and screw accuracy were analyzed between the three groups. The preoperative plan overlapped with the postoperative O-arm scan to determine if the screws were executed as planned. Results: The frequency of clinically acceptable screw placement (Gertzbein-Robbins grades A and B) in the freehand, fluoroscopy-assisted, and robotic-assisted groups were 97.7%, 98.6%, and 99.34%, respectively. With robotic assistance, an experience-neutralizing effect implied that surgeons with varying levels of experience achieved comparable pedicle screw accuracy, blood loss, O-arm time, robot time, and time per screw. No significant difference in these parameters was found between surgeries commencing before and after 2 PM. No significant differences were noted between the planned and executed screw trajectories in the robotic-assisted group irrespective of surgical experience. Conclusions The third-generation robotic-assisted pedicle screw placement system used in conjunction with intraoperative threedimensional O-arm imaging consistently demonstrates safe and accurate screw placement with an experience-neutralizing effect.

Methods: In this prospective study, a total of 1,120 pedicle screws were placed in the freehand group (n=175), 1,250 in the fluoroscopyassisted group (n=172), and 1,225 in the robotic-assisted group (n=180). Surgical parameters and screw accuracy were analyzed between the three groups. The preoperative plan overlapped with the postoperative O-arm scan to determine if the screws were executed as planned. Results: The frequency of clinically acceptable screw placement (Gertzbein-Robbins grades A and B) in the freehand, fluoroscopy-assisted, and robotic-assisted groups were 97.7%, 98.6%, and 99.34%, respectively. With robotic assistance, an experience-neutralizing effect implied that surgeons with varying levels of experience achieved comparable pedicle screw accuracy, blood loss, O-arm time, robot time, and time per screw. No significant difference in these parameters was found between surgeries commencing before and after 2 PM. No significant differences were noted between the planned and executed screw trajectories in the robotic-assisted group irrespective of surgical experience. Conclusions The third-generation robotic-assisted pedicle screw placement system used in conjunction with intraoperative threedimensional O-arm imaging consistently demonstrates safe and accurate screw placement with an experience-neutralizing effect.