Feasibility analysis and nail planning ofS2 iliac crest screw placement in children / 中国骨伤

OBJECTIVE@#To evaluate the feasibility of S2 alar iliac screw insertion in Chinese children using computerized three-dimension reconstruction and simulated screw placement technique, and to optimize the measurement of screw parameters.@*METHODS@#A total of 83 pelvic CT data of children who underwent pelvic CT scan December 2018 to December 2020 were retrospectively analyzed, excluding fractures, deformities, and tumors. There were 44 boys and 39 girls, with an average age of (10.66±3.52) years, and were divided into 4 groups based on age (group A:5 to 7 years old;group B:8 to 10 years old;group C:11-13 years old;group D:14 to 16 years old). The original CT data obtained were imported into Mimics software, and the bony structure of the pelvis was reconstructed, and the maximum and minimum cranial angles of the screws were simulated in the three-dimensional view with the placement of 6.5 mm diameter S2 alar iliac screws. Subsequently, the coronal angle, sagittal angle, transverse angle, total length of the screw, length of the screw in the sacrum, width of the iliac, and distance of the entry point from the skin were measured in 3-Matic software at the maximum and minimum head tilt angles, respectively. The differences among the screw parameters of S2 alar iliac screws in children of different ages and the differences between gender and side were compared and analyzed.@*RESULTS@#In all 83 children, 6.5 mm diameter S2 iliac screws could be placed. There was no significant difference between the side of each screw placement parameter. The 5 to 7 years old children had a significantly smaller screw coronal angle than other age groups, but in the screw sagittal angle, the difference was more mixed. The 5 to 7 years old children could obtain a larger angle at the maximum head tilt angle of the screw, but at the minimum cranial angle, the larger angle was obtained in the age group of 11 to 13 years old. There were no significant differences among the age groups. The coronal angle and sagittal angle under maximum cephalic angle and minimum cranial angle of 5 to 7 years old male were (40.91±2.91)° and (51.85±3.75)° respectively, which were significantly greater than in female. The coronal angle under minimum cranial angle was significantly greater in girls aged 8-10 years old than in boys. For the remaining screw placement angle parameters, there were no significant differences between gender. The differences in the minimum iliac width, the screw length, and the length of the sacral screws showed an increasing trend with age in all age groups. The distance from the screw entry point to the skin in boys were significantly smaller than that of girls. The minimum width of the iliac in boys at 14 to 16 years of age were significantly wider than that in girls at the same stage. In contrast, in girls aged 5 to 7 years and 11 to 13 years, the screw length was significantly longer than that of boys at the same stage.@*CONCLUSION@#The pelvis of children aged 5 to 16 years can safely accommodate the placement of 6.5 mm diameter S2 alar iliac screws, but the bony structures of the pelvis are developing and growing in children, precise assessment is needed to plan a reasonable screw trajectory and select the appropriate screw length.

Surgical treatment of thoracolumbar fractures using pedicle screws fixation at the level of the fracture: results for following up more than 2 years / 中国骨伤

<p><b>OBJECTIVE</b>To explore clinical efficacy of thoracolumbar fractures fixation with pedicle screws fixation at the level of the fracture and monosegment bone graft simultaneously.</p><p><b>METHODS</b>Retrospective analysis of 32 patients with thoracolumbar fractures underwent surgical procedure of pedicle screws fixation at the level of the fracture and monosegment bone graft simultaneously from January 2006 to December 2008. All the patients were followed up more than two years. There were 25 males and 7 females with an average age of 39.1 years (ranged, 25 to 60 years). According to the AO classification, type A1.3 was in 5 cases, type A3.1 in 17, type A3.3 in 8, type C1.1 in 1, and type C1.3 in 1. Load scoring was from 4 to 7 points with average of 5.8 points. The spinal cord function according to Frankel grade, grade A was in 2 cases, grade B in 2, grade C in 5, grade D in 9 and grade E in 14. Cobb angle, the height of anterior border of vertebral body, spinal canal stenosis rate were observed by X-ray films. Meanwhile, pain and work ability were evaluated by Denis scale.</p><p><b>RESULTS</b>All the patients were followed-up from 30 to 48 months (averaged, 39.2 months). No internal fixation loosening or breakage were found. Three cases occurred with floating callus and other obtained well bone fusion. Compared with preoperation, Cobb angle, the height of anterior border of vertebral body, and spinal canal stenosis rate improved obviously (P < 0.05); but Cobb angle had lost partially at the last follow-up (P > 0.05). Meanwhile, anterosuperior part of vertebral body of 25 cases existed cavity phenomenon. The nerve function of all cases recovered for 1-2 grades, except for 2 cases without change whose spinal cord function was degree A preoperatively. According to Denis scale, lower back pain scoring, P1 was in 22 cases, P2 in 7, P3 in 3; state of work scoring, W1 was in 18 cases, W2 in 8, W3 in 3, W5 in 3.</p><p><b>CONCLUSION</b>It can help to correct the kyphosis and improve low back pain in thoracolumbar fractures through pedicle screws fixation at the level of the fracture and monosegment bone graft simultaneously, but it can not improve the cavity phenomenon of injured vertebral body and avoid partially lost of Cobb angle.</p>