Measurement of the maximum corridor parameters of infra acetabular screw and evaluation of the feasibility of screw insertion by digital analysis / 中国骨伤

OBJECTIVE@#To measure the maximum corridor parameters of the infra acetabular screw and evaluate the feasibility of screw insertion through digital analysis of the acetabular structure.@*METHODS@#The pelvic CT data of 100 patients who received plain pelvic CT scan from April 2013 to June 2015 were retrospectively analyzed. There were 50 males, aged 20 to 84 years, with an average age of (48.42±17.48) years, and 50 females, aged 18 to 87 years, with an average age of (55.02±19.54) years. Patients with acetabular fractures, hip dysplasia, and metal implants in the acetabulum were excluded. Import CT data into Mimics software in DICOM format to generate a three-dimensional model, and find the axialprojection of the infra-acetabular corridor in the middle of the pubis ramus in the inlet view. A virtual screw was placed in the infra-acetabular space and measure the parameters including the diameter and the length of the maximum corridor, the distance from the insertion point to the pubic symphysis, to the anterosuperior iliac spine and to the medial edge of the pelvis. Then import the pelvic model into 3- matic software, establish the pelvic model anterior pelvic plane and median sagittal plane, and measure the angle between the screw axis and the two planes. A minimum corridor diameter of at least 5 mm was defined as a cutoff for placing a 3.5 mm screw, and calculate the screw insertion rate.@*RESULTS@#In 100 cases, 49% of patients had a infra acetabular corridor with a diameter ≥5 mm, and the rate of screw placement in men was significantly higher than that in women. The average diameter of the maximum corridor of infra-acetabular screw was (4.86±1.72) mm, the average length was (94.04±8.29) mm, the average distance from the insertion point to the pubic symphysis was (60.92±4.84) mm, to the anterosuperior iliac spine was (85.15± 6.85) mm, and to the medial edge of the pelvis was (6.12±3.32) mm. The mean angle between the axis of the screw and the median sagittal plane was (-1.38±4.74)°, and the mean angle between the axis of the screw and the anterior pelvic plane was (56.77±7.93)°. There are significant differences between male and female measured parameters, except for the angle between the screw axis and the anterior pelvic plane. There was no statistically significant difference in the maximum corridor parameters of infra-acetabular screw on both sides of the pelvis.@*CONCLUSION@#This study shows that the insertion rate of infra-acetabular screws is low in local patients, and the feasibility of screw insertion should be fully evaluated before surgery.

Analysis of hidden blood loss and its risk factors in the treatment of osteoporotic vertebral compression fractures with PVP / 中国骨伤

OBJECTIVE@#To investigate the influencing factors of hidden blood loss (HBL) during the treatment of percutaneous vertebroplasty (PVP).@*METHODS@#The clinical data of 125 patients with osteoporotic vertebral compression fractures (OVCFs) treated with percutaneous vertebroplasty from March 2016 to December 2017 were retrospectively analyzed. All patients underwent X rays of the AP and lateral lumbar spine, double oblique, and dynamic positions. Lumbar spine CT, MRI, and dual energy X ray bone densitometer (DXA) were used to confirm the diagnosis. There were 55 males and 70 females, 10 cases of thoracic vertebrae, 89 cases of thoracolumbar vertebrae, 26 cases of lumbar vertebrae, 87 cases with single segment, 29 cases with double segment,and 9 cases with 3 segments. The vertebral compression height ratios of 67 patients were less than 1 / 3, and the ratios for 41 patients were from 1 / 3 to 2 / 3,for 17 patients were more than 2 / 3. Blood routine examination were performed before and 3 days after surgery to analyze hidden blood loss and to explore its risk factors.@*RESULTS@#The average hidden blood loss was (317±156) ml in 125 patients. Multiple linear regression analysis revealed a history of diabetes(=0.011),surgical segments(=0.036),number of segments (<0.001),vertebral height loss rate (=0.002),vertebral height recovery rate (<0.001) and bone cement leakage rate (=0.003) were positively correlated with hidden blood loss. Moreover,it was found that the blood loss was higher in those with higher vertebral height loss rate than in those with lower vertebral height loss rate, and the blood loss was higher in those with good vertebral height recovery than those with poor vertebral height recovery. Additionally,the cement leakage was also an important factor in increasing hidden blood loss. However,there was no significant correlation between bone mineral density(=0.814) or history of hypertension(=0.055) and hidden blood loss.@*CONCLUSION@#Patients with OVCFs have a large amount of hidden blood loss after PVP treatment, which needs attention. At the same time, the history of diabetes, surgical segments, number of segments, bone cement leakage rate, vertebral height loss rate and vertebral height recovery rate are the risk factors for hidden blood loss.

Analysis of the clinical effects of different pedicle screw fixation methods for the treatment of thoracolumbar fractures / 中国骨伤

OBJECTIVE@#To discuss the clinical effects of the different pedicle screw fixation methods for the treatment of thoracolumbar fractures.@*METHODS@#The clinical data of 55 patients with single thoracolumbar fractures treated between January 2013 and December 2016 were retrospectively analyzed. There were 32 males and 23 females, aged from 20 to 55 years with an average of 35.6 years old. All the fractures were located on a single segment, 8 cases of T₁₁, 18 cases of T₁₂, 19 cases of L₁, 10 cases of L₂. According to the classification of AO, 10 cases were type A1, 17 cases were type A2, 18 cases were type A3, 7 cases were type B2, 2 cases were type B3, 1 case was type C1. The patients were divided into three groups according to the different fixation methods, among them, 20 cases treated by traditional short-segment 4 pedicle screws fixation were control group, 22 cases treated by intermediate bilateral pedicle screws fixation (6 pedicle screws fixation) were bilateral group, 13 cases treated by intermediate unilateral pedicle screw fixation (5 pedicle screws fixation) were unilateral group. The three groups were compared by operation time, intraoperative blood loss, hospitalization cost, VAS and ODI scores, the correction of the fractured vertebrae height and kyphosis angle postoperatively and the losing rate of the fractured vertebrae height and kyphosis angle at the final follow-up and so on.@*RESULTS@#All the patients were followed up from 12 to 20 months with an average of 15.2 months. No complications such as loosening of internal fixation and breakage were found after operation. There was no significant difference in operation time and intraoperative blood loss among three groups(>0.05). In terms of hospitalization cost, the control group[(20 932.4±298.3)yuan] was significantly lower than the unilateral group[(22 428.2±321.5)yuan] and the bilateral group [(23 630.5±310.5)yuan] (0.05). And there was no significant difference in the correction of the injuried vertebrae height and kyphosis angle immediately after operation among three groups(>0.05). However, for the losing rate of the injuried vertebrae height at the final follow-up, the unilateral group[(6.3±2.1)%] and bilateral group [(5.6±2.8)%] were significantly better than the control group[(9.2±1.8)%] (0.05).@*CONCLUSIONS@#All the three different pedicle screw fixation methods are suitable for the treatment of thoracolumbar fractures and the short-term clinical effects are consistent. Compared with traditional short-segment 4 pedicle screws fixation, intermediate bilateral or unilateral pedicle screw fixation were more effective in maintaining the height of the injuried vertebrae and preventing the occurrence of kyphosis. The intermediate unilateral pedicle screw fixation was comparable to that of bilateral fixation at clinical outcomes, but the unilateral fixed hospitalization cost was lower, which was worthy of clinical promotion.