Objective: To investigate the surgical strategy, safety, and efficacy of close reduction and robot-aided minimally invasive lumbopelvic fixation in treatment of traumatic spinopelvic dissociation. Methods: Data of 32 patients (21 males and 11 females) with traumatic spinopelvic dissociation treated by lumbopelvic fixation with robot-aided minimally invasive technique or conventional open procedure in our institution from March 2010 to April 2019 were retrospectively analyzed, and divided into robot group and control group. Intraoperative blood loss, surgical time, fluoroscopy frequency, total drilling times, infection rate, hospitalization time, and sacral fracture healing time were reviewed. Radiographs and computed tomography (CT) scans were totally acquired to evaluate the reduction quality, residual fracture displacement, and Gras classification on screws insertion after surgery. According to the Majeed scoring system, functional outcome was assessed for each patient at the final follow-up. Results: There were 12 patients in the robot group and 20 patients in the control group with no significant difference about the demographic data. The average surgical time was 148.3 ± 40.5 min with intraoperative blood loss of 142.5±36.7 mL in the robot group and 185.0 ± 47.8 min with 612.5 ± 182.7 mL in the control group (P = 0.034, P = 0.000). The robot group had a shorter mean hospitalization time at 19.9 ± 7.0 days compared to the control group with 28.6 ± 5.4 days (P = 0.010). The fluoroscopy frequency was 35.4 ± 3.0 in the robot group and 45.5 ± 3.6 in the control group (P = 0.000) and total drilling times were 7.1 ± 1.1 and 9.6 ± 1.3 (P = 0.000), respectively. The infection rate was 0% (0/12) in the robot group and 15% (3/20) in the control group (P = 0.159). According to the Gras classification on screw positioning, there were 11 cases in Grade I and 1 case in Grade II in the robot group, and 14 cases in Grade I and 6 cases in Grade II in the control group. All the patients were followed up consecutively for at least 12 months, with an average follow-up period of 17.1 ± 3.6 months. All sacral fractures healed with an average time of 3.8 ± 0.6 months in the robot group and 4.7 ± 0.7 months in the control group (P = 0.000). According to Majeed functional assessment investigation, the mean score of the patients was 87.2 ± 4.0 in the robot group and 83.1 ± 4.5 in the control group (P = 0.015). Conclusions: Robot-aided minimally invasive lumbopelvic fixation for traumatic spinopelvic dissociation is a safe and feasible option with advantages of less intraoperative blood loss, less radiation damage, less hospitalization time, and better functional outcome.

The human orbitofrontal cortex (OFC) is an enigmatic brain region that cannot be parcellated reliably using diffusional and functional magnetic resonance imaging (fMRI) because there is signal dropout that results from an inherent defect in imaging techniques. We hypothesise that the OFC can be reliably parcellated into subregions based on gray matter volume (GMV) covariance patterns that are derived from artefact-free structural images. A total of 321 healthy young subjects were examined by high-resolution structural MRI. The OFC was parcellated into subregions-based GMV covariance patterns; and then sex and laterality differences in GMV covariance pattern of each OFC subregion were compared. The human OFC was parcellated into the anterior (OFCa), medial (OFCm), posterior (OFCp), intermediate (OFCi), and lateral (OFCl) subregions. This parcellation scheme was validated by the same analyses of the left OFC and the bilateral OFCs in male and female subjects. Both visual observation and quantitative comparisons indicated a unique GMV covariance pattern for each OFC subregion. These OFC subregions mainly covaried with the prefrontal and temporal cortices, cingulate cortex and amygdala. In addition, GMV correlations of most OFC subregions were similar across sex and laterality except for significant laterality difference in the OFCl. The right OFCl had stronger GMV correlation with the right inferior frontal cortex. Using high-resolution structural images, we established a reliable parcellation scheme for the human OFC, which may provide an in vivo guide for subregion-level studies of this region and improve our understanding of the human OFC at subregional levels.

Background This retrospective study from a single center aimed to compare patient outcomes following TiRobot-assisted sacroiliac screw fixation and bone grafting with traditional screw fixation without bone grafting in 33 patients with unstable osteoporotic sacral fracture (UOSF). Material/Methods Patients with UOSF were included and divided into 2 groups: a TiRobot-assisted surgical group with 18 patients (robot-aided sacroiliac screw fixation and bone grafting) and a standard surgical group with 15 patients (free-hand screw fixation without bone grafting). T values of bone mineral density (BMD) ≤-2.5 standard deviation (SD) were diagnosed as osteoporosis. Screw positioning and fracture healing time were evaluated. Functional outcomes were investigated at the final follow-up. Results There were no statistically significant differences in screw positioning; however, there were satisfactory positioning rates in 94.4% (17/18) of patients in the TiRobot-assisted surgical group and 73.3% (11/15) in the standard surgical group. The advantages with TiRobot on surgical time of screw placement, fluoroscopy frequency, and total drilling times were noted ( P =0.000). The nonunion rates were 5.6% (1/18) in the TiRobot-assisted surgical group and 33.3% (5/15) in the standard group ( P =0.039). Healing time in the union cases had a significant difference ( P =0.031). Functional outcome scores in the TiRobot-assisted surgical group were superior to that in the standard group ( P =0.014). Conclusions The findings showed that TiRobot-assisted sacroiliac screw fixation and bone grafting was a safe and effective surgical treatment option that had a reduced radiation dose and improved fracture healing, when compared with standard screw fixation without bone grafting.

Objective To evaluate the clinical outcomes of the treatment of unilateral unstable sacral fractures by fixation with the posterior INFIX (posterior pelvic ring screw‐rod internal fxation). Methods Data of 60 patients with unilateral unstable sacral fractures who underwent surgery from March 2013 to March 2020 were retrospectively analyzed according to the selection criteria. All patients were associated with anterior pelvic ring injuries, and the operations were performed by the same team of surgeons. According to the different types of internal fixation, the patients were divided into two groups, which both included 30 patients: the posterior INFIX group and iliosacral screw fixation group. The demographic and clinical data of the two patient groups, such as age, sex, sacral fracture types based on the Denis classification, operation time, amount of intraoperative bleeding, intraoperative fluoros copy time, Majeed pelvic score at final follow‐up, and quality of fracture reduction based on Mears and Velyvis's imaging classification criteria were collected by the same researcher and compared statistically. Results All patients were continuously followed up for 23.17 ± 3.34 months (range, 12 to 46 months). All sacral fractures healed with an average healing time of 9.3 ± 2.24 months (range, 6 to 18 months). None of the patients had re‐displacement of the fracture or fixation failure. Compared to the iliosacral screw group, the posterior INFIX group patients had more intraoperative bleeding (t = 3.59, P < 0.001), shorter operation time (t = 4.49, P < 0.001), and shorter intraoperative fluoroscopy time (t = 6.26, P < 0.001). There were no statistical differences between the two groups in terms of age, sex, fracture type, Majeed score, and quality of fracture reduction (P > 0.05). In the posterior INFIX group, one patient had a superficial wound infection and one patient complained of discomfort due to a prominent fixation. In the iliosacral screw fixation group, one patient had intraoperative iatrogenic S1 nerve injury and vessel injury. The posterior INFIX fixation was a simpler manipulation with higher safety, shorter time of operation and intraoperative fluoroscopy, and similar clinical outcomes compared to iliosacral screw fixation. Conclusion For the treatment of unilateral unstable sacral fractures, the posterior INFIX fixation can be recommended in clinic application.

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