A case-control study of cervical spine Key-hole technique and anterior cervical Zero-P system in the treatment of cervical spondylotic radiculopathy / 中国骨伤

OBJECTIVE@#To explore the short-term clinical efficacy of single-stage cervical spondylotic radiculopathy (CSR) between the minimally invasive Key-hole technique and anterior cervical Zero profile intervertebral fusion system (Zero-P).@*METHODS@#A retrospective analysis was performed on 45 patients who underwent surgical treatment for CSR from January 2017 to January 2020, including 21 in Key hole group (12 males and 9 females), followed up for 10-22(13.2±2.3) months;24 cases in Zero-P group (14 males and 10 females), and the follow up period was 10 to 23(12.7±1.9) months. Perioperative conditions (incision length, intraoperative blood loss, operation time, length of hospital stay, and complications) were compared between two groups, and X-rays of cervical spine before and after surgery and at the final follow-up were taken to analyzed curvature of the cervical spine, visual analogue scale(VAS) of pain before and after surgery, Oswestry Disability Index(ODI) and Japanese Orthopaedic Association (JOA) score of cervical spine were recorded to evaluate clinical efficacy.@*RESULTS@#In Key-hole group and Zero-P group, the surgical incision length, intraoperative blood loss, operation time, final follow-up Cobb angle and immediate postoperative VAS score respectively were (1.2±0.2) cm, (5.3±0.3) cm;(35.3±9.7) ml, (120.2±13.5) ml;(56.4±11.3) min, (90.6±12.6) min;(3.2±3.9)°, (7.3±3.8)°;(2.8±1.2)points, (3.8±1.1) points;the Zero-P group was larger than the Key hole group, with statistical significance(@*CONCLUSION@#The cervical spine Key-hole technology is similar to the anterior cervical Zero-P system in the treatment of CSR. The Key-hole technique has certain advantages in incision length, intraoperative blood loss, and operation time. It is a safe, effective and can be widely used cervical spine surgery method.

Precision and biomechanical properties of 3D printed artificial bone trabeculae based on Voronoi Tessellation algorithm / 中华创伤杂志

Objective:To investigate the processing accuracy and biomechanical properties of 3D printed artificial bone trabeculae with different porosity generated by the Voronoi Tessellation algorithm, and to provide a reference for improving the biomechanical properties of titanium alloy implants in orthopedics.Methods:A healthy adult male volunteer (aged: 30 years, tall: 175 cm and weight: 70 kg) was selected to collect CT scan data of the lumbar spine. Five kinds of biomimetic artificial bone trabeculae with different porosity were generated using the Voronoi Tessellation algorithm, and divided into Tra_A (73.7%), Tra_B (74.1%), Tra_C (80.0%), Tra_D (80.2%) and Tra_E (85.7%) groups according to the porosity. Selective laser melting (SLM) 3D printing technology was used to process trabecular bone structures with different porosity into titanium alloy prosthesis with a diameter of 18 mm and a height of 20 mm. Each group had 3 samples. The internal structure of each sample was observed by industrial microscope, and the actual porosity of artificial bone trabecular of each group was calculated and compared with the theoretical porosity to evaluate the machining accuracy of artificial bone trabecular with different porosity. Finally, the ultimate load, yield strength and elastic modulus of each sample were evaluated by in vitro mechanical test, and the biomechanical properties of artificial bone trabeculae with different porosity were evaluated.Results:There were no cracks, fracture of connecting rod or accumulation of titanium alloy powder in all specimens. The average actual porosity of the five groups of artificial bone trabecular specimens was 66.0%, 65.5%, 71.8%, 72.5% and 78.1%, respectively. Compared with the theoretical porosity, it was smaller by 10.5%, 11.6%, 10.2%, 9.7% and 8.8%, respectively. In the in vitro mechanical tests for the five groups of artificial bone trabecular specimens, the mean value of ultimate load was 23.6 kN, 18.9 kN, 17.0 kN, 16.3 kN, 10.7 kN, respectively; the mean value of yield strength was 72.2 MPa, 58.7 MPa, 54.9 MPa, 52.2 MPa, and 36.1 MPa, respectively; the mean value of the actual elastic modulus was 7.5 GPa, 6.3 GPa, 4.5 GPa, 4.3 GPa and 2.4 GPa, respectively. With the increase of the porosity of artificial bone trabeculae, all three indicators above showed a decreasing trend. Conclusions:The artificial bone trabeculae generated by the Voronoi Tessellation algorithm and printed by SLM 3D have better machining quality. With the increase of porosity, the processing precision of the titanium alloy artificial bone tray specimens is better. Limit load, yield light and elastic modulus of artificial bone trabecula decrease with the increase of porosity.

Clinical characteristics analysis of lumbar disc herniation with symptom aggravated caused by spinal manipulative therapy / 中国骨伤

<p><b>OBJECTIVE</b>To discuss the characteristics of lumbar disc herniation (LDH) with symptom aggravated caused by spinal manipulative therapy (SMT).</p><p><b>METHODS</b>Detailed clinical profiles of a total number of 10 LDH patients with symptoms aggravated after SMT were reviewed including 5 males and 5 females with age from 46 to 68 years old, 7 patients of them were more than 50 years old. The clinical data of 10 patients were analyzed involving age, gender, clinical symptoms, signs, imaging findings, surgical treatment and prognosis. Laminectomy and discectomy were performed, and follow-up was carried out in all patients.</p><p><b>RESULTS</b>The duration of symptoms in all the patients before SMT was 4 to 15 years. After the therapy, an acute exacerbation of back and radicular pain was observed within 24 hours. MRI showed intervertebral disc herniation, 7 patients were observed in L4-L5. The time internal between the exacerbation of presentation and surgery was 23.1 days. No perioperative complications occurred. All the patients were relieved of radicular pain a few days after surgery. During postoperative follow-up, all patients regained the ability to walk; Eight patients reported a complete resolution of presentation and the rest two patients were significantly improved.</p><p><b>CONCLUSIONS</b>SMT should be prohibited in some LDH patients to prevent neurological damages, in whom there are 5 possible risk factors.</p>