Objective:To evaluate the efficacy of 3D printing technology combined with computer navigation-assisted screw implantation in the treatment of atlantoaxial instability (AAI) complicated by vertebral artery anomalies.Methods:A retrospective case series study was conducted to analyze the clinical data of 23 patients with AAI complicated by vertebral artery anomalies who were admitted to Honghui Hospital of Xi′an Jiaotong University between January 2019 and January 2023, including 10 males and 13 females, aged 19-70 years [(51.0±13.3)years]. Vertebral artery anomalies were categorized into unilateral high-riding vertebral artery with unilateral dominance ( n=14), bilateral high-riding vertebral arteries with unilateral dominance ( n=6), and ponticulus posticus ( n=3). All the patients underwent preoperative planning using a 3D-printed model of the atlantoaxial complex with the vertebral artery, followed by posterior atlantoaxial pedicle screw fixation with computer-assisted navigation. Operative duration and intraoperative blood loss were recorded. The accuracy of pedicle screw placement was assessed at 3 days postoperatively using the Gertzbein-Robbins classification. Visual analogue scale (VAS) scores and Japanese Orthopedic Association (JOA) scores were evaluated preoperatively, at 3 days, 3 months postoperatively, and at the last follow-up. Bony fusion was assessed using cervical CT with 3D reconstruction at the last follow-up. Complications were also observed. Results:All the patients were followed up for 12-19 months [(15.1±1.9)months]. The operative duration was 125-167 minutes [(140.6±10.9)minutes] and intraoperative blood loss was 200-600 ml [(295.7±77.8)ml]. At 3 days postoperatively, all the 66 pedicle screws were safely placed, with 60 screws (91%) rated as Gertzbein-Robbins Grade 0 and 6 screws (9%) as Grade 1. At 3 days and 3 months postoperatively, and at the last follow-up, the VAS scores were (4.0±1.0)points, (2.0±0.6)points, and (1.3±0.5)points, and the JOA scores were (14.2±1.2)points, (16.0±0.8)points, and (16.6±0.5)points, both of which were not only significantly improved compared with preoperative (5.6±1.3)points and (12.8±1.5)points, but also further improved over time ( P<0.05). At the last follow-up, 22 patients (96%) achieved satisfactory atlantoaxial bony fusion. No vertebral artery injury, spinal cord or nerve injury, cerebrospinal fluid leakage, or screw loosening were observed in any patients. Conclusion:For patients with AAI complicated by vertebral artery anomalies, 3D printing combined with computer navigation-assisted navigation for atlantoaxial pedicle screw implantation offers multiple advantages, including minimal surgical trauma, high screw placement accuracy, pain relief, neurological function improvement, high fusion rate, and lowered incidence of complications.

Objective:To evaluate the efficacy of 3D printing technology combined with computer navigation-assisted screw implantation in the treatment of atlantoaxial instability (AAI) complicated by vertebral artery anomalies.Methods:A retrospective case series study was conducted to analyze the clinical data of 23 patients with AAI complicated by vertebral artery anomalies who were admitted to Honghui Hospital of Xi′an Jiaotong University between January 2019 and January 2023, including 10 males and 13 females, aged 19-70 years [(51.0±13.3)years]. Vertebral artery anomalies were categorized into unilateral high-riding vertebral artery with unilateral dominance ( n=14), bilateral high-riding vertebral arteries with unilateral dominance ( n=6), and ponticulus posticus ( n=3). All the patients underwent preoperative planning using a 3D-printed model of the atlantoaxial complex with the vertebral artery, followed by posterior atlantoaxial pedicle screw fixation with computer-assisted navigation. Operative duration and intraoperative blood loss were recorded. The accuracy of pedicle screw placement was assessed at 3 days postoperatively using the Gertzbein-Robbins classification. Visual analogue scale (VAS) scores and Japanese Orthopedic Association (JOA) scores were evaluated preoperatively, at 3 days, 3 months postoperatively, and at the last follow-up. Bony fusion was assessed using cervical CT with 3D reconstruction at the last follow-up. Complications were also observed. Results:All the patients were followed up for 12-19 months [(15.1±1.9)months]. The operative duration was 125-167 minutes [(140.6±10.9)minutes] and intraoperative blood loss was 200-600 ml [(295.7±77.8)ml]. At 3 days postoperatively, all the 66 pedicle screws were safely placed, with 60 screws (91%) rated as Gertzbein-Robbins Grade 0 and 6 screws (9%) as Grade 1. At 3 days and 3 months postoperatively, and at the last follow-up, the VAS scores were (4.0±1.0)points, (2.0±0.6)points, and (1.3±0.5)points, and the JOA scores were (14.2±1.2)points, (16.0±0.8)points, and (16.6±0.5)points, both of which were not only significantly improved compared with preoperative (5.6±1.3)points and (12.8±1.5)points, but also further improved over time ( P<0.05). At the last follow-up, 22 patients (96%) achieved satisfactory atlantoaxial bony fusion. No vertebral artery injury, spinal cord or nerve injury, cerebrospinal fluid leakage, or screw loosening were observed in any patients. Conclusion:For patients with AAI complicated by vertebral artery anomalies, 3D printing combined with computer navigation-assisted navigation for atlantoaxial pedicle screw implantation offers multiple advantages, including minimal surgical trauma, high screw placement accuracy, pain relief, neurological function improvement, high fusion rate, and lowered incidence of complications.

Objective To observe the phenotypic transformation of bone marrow mesenchymal stem cells(MSC) transfected with hepatocyte growth factor(HGF) after their transplantation in the rat's kidney with partial unilateral ureteral obstruction(PUUO).Methods We isolated,cultured bone MSCs of the male rats,and transfected them with Ad-HGF in vitro.Thirty-six female rats with PUUO were randomly divided into control group(A) and the experimental groups(B,C).Saline,Ad-GFP transfected MSCs or Ad-HGF transfected MSCs were respectively injected into the parenchyma of kidney on the 7th day with PUUO.We released the ureteral obstruction of rats after transplantation.Kidney tissue of the rats were collected on the 7th day after transplantation.The distribution and phenotypic transformation of MSCs in the kidney were determined by immunofluorescence method.Results The green fluorescent-labeled MSCs mainly distributed in the tubular cells,and a part of bone MSCs underwent phenotypic transformation after transplantation.Compared with group B,the number of bone MSCs with phenotypic transformation significantly increased in group C.Conclusion After transplantation,MSCs can survive and differentiate into renal tubular epithelial cells,and HGF may promote survival and differentiation of MSCs.