Evaluation of pedicle screw placement by pedicle channel grade in adolescent idiopathic scoliosis: should we challenge narrow pedicles?

BACKGROUND: Surgeons often have concerns about whether to place screws in narrow pedicles for correction of scoliosis. The aim of this study was to use pedicle channel grades based on preoperative CT to evaluate pedicle screw placement in posterior surgery for adolescent idiopathic scoliosis. METHODS: The subjects comprised 55 patients who underwent posterior correction and fusion, and a total of 810 pedicles were examined in which screw placement had been planned and probing had been performed. Pedicle channel grades were determined by measuring inner pedicle diameter on preoperative CT scans. The grades were defined as grade 1 with an inner diameter of ≥ 4 mm, grade 2 with an inner diameter of ≥ 2 mm and < 4 mm, grade 3 with an inner diameter of ≥ 1 mm and < 2 mm, and grade 4 for a "cortical channel" with an inner diameter of < 1 mm. RESULTS: The failure rate of screw placement was 0.5 % for pedicle channel grade 1, 2.9 % for grade 2, 12.0 % for grade 3, and 31.5 % for grade 4, showing significant differences (p < 0.001). For the laterality of curvature, the failure rate was 5.9 % for the convex side, 8.0 % for the neutral vertebra, and 9.0 % for the concave side, showing no significant difference. There was also no significant difference in failure rate between degrees of curvature of < 60° (8.2 %) and ≥ 60° (5.6 %). Logistic analysis showed that the pedicle channel grade was a significant risk factor for failure (odds ratio 4.0, p < 0.001). CONCLUSIONS: The failure rate of screw placement was 31.5 % for a cortical channel with a pedicle inner diameter of < 1 mm. Screw placement should be attempted in pedicles with an inner diameter of 1 mm or larger.

Doping control analyses during the Tokyo 2020 Olympic and Paralympic Games.

The doping control analyses at the XXXII Olympic Games (July 23 to August 8, 2021) and the XVI Paralympic Games (August 24 to September 5, 2021) held in Tokyo, Japan, after a year of delay due to the COVID-19 pandemic are summarized in this paper. A new satellite facility at the existing World Anti-Doping Agency (WADA)-accredited Tokyo laboratory was established and fully operated by 278 staff, including 33 Tokyo laboratory staff, 49 international experts, and 196 Japanese temporary staff. The numbers of urine samples were 5081 (Olympics) and 1519 (Paralympics), and the numbers of blood samples were 1103 (Olympics) and 500 (Paralympics). The laboratory could prepare for analysis in advance using a paperless chain-of-custody system, allowing for faster turnaround time reporting. For the first time, a new polymerase chain reaction method for detecting erythropoietin (EPO) gene doping was used. The laboratory also analyzed blood samples for detecting steroid esters following the spotting of collected venous EDTA blood onto dried blood spot cards. Moreover, full-scan data acquisition using high-resolution mass spectrometers was performed for all urine samples, allowing for detecting traces of doping substances, which are not currently analyzed in the subsequent data processing. The presence of some prohibited substances was confirmed, resulting in 8 atypical findings (ATFs) and 11 adverse analytical findings (AAFs), including homologous blood transfusion (2 cases) and recombinant EPO in the blood (1 case), at the Olympics, whereas 2 ATFs and 10 AAFs were reported at the Paralympics.