Preliminary application of 3D-printed individualised guiding templates for total hip arthroplasty in Crowe type IV developmental dysplasia of the hip.

OBJECTIVE: To evaluate the feasibility and accuracy of three-dimensional (3D)-printed individualised guiding templates in total hip arthroplasty (THA) for the treatment of developmental dysplasia of the hip (DDH). METHODS: 12 hips in 12 patients with Crowe type IV DDH were treated with THA. A 3D digital model of the pelvis and lower limbs was reconstructed using the computed tomography data of the patients. Preoperative surgical simulations were performed to determine the most suitable surgical planning, including femoral osteotomy and prosthesis placement. Based on the ideal surgical planning, individualised guiding templates were designed by software, manufactured using a 3D printer, and used in acetabulum reconstruction and femoral osteotomy during surgery. RESULTS: 12 patients were followed up for an average of 72.42 months (range 38-135 months). During surgery, the guiding template for each case was matched to the bony markers of the acetabulum and proximal femur. Preoperative and follow-up Harris Hip Scores were 34.2 ± 3.7 and 85.2 ± 4.2; leg-length discrepancy, 51.5 ± 6.5 mm and 10.2 ± 1.5 mm; and visual analogue scale scores, 6.2 ± 0.8 and 1.3 ± 0.3, respectively, with statistical difference. Shortened deformity and claudication of the affected limb were obviously improved after surgery. However, 1 patient had artificial hip dislocation 2 weeks after surgery, and another patient had sciatic nerve traction injury, both of whom recovered after physical treatment. CONCLUSIONS: Preoperative surgical simulation and 3D-printed individualised guiding templates can fulfil surgeon-specific requirements for the treatment of Crowe type IV DDH. Accurate THA can be achieved using 3D-printed individualised templates, which provide a new personalised surgical plan for the precise positioning and orientation of acetabular reconstruction and femoral osteotomy.

Three-Dimensional Printing Technology for Surgical Correction of Congenital Scoliosis Caused by Hemivertebrae.

OBJECTIVE: This study aimed to explore the clinical application of three-dimensional (3D) printing technology in the surgical treatment of congenital scoliosis caused by hemivertebrae. METHODS: Twenty-four patients (11 in the 3D-printing group and 13 in the conventional group) with scoliosis secondary to a single hemivertebra were retrospectively reviewed. All patients underwent hemivertebrectomy and short-segment fixation. Virtual preoperative planning, operation simulation, and intraoperative application of 3D-printed patient-specific templates were performed in the 3D-printing group. Hemorrhage volume, operation time, transfusion, and complications were noted. Radiographic parameters were evaluated preoperatively, postoperatively, and at final follow-up. RESULTS: All patients had different degrees of successfully corrected scoliosis. There was a similar correction of the Cobb angle postoperatively between the 2 groups. The operation time, blood loss, transfusion, time for the insertion of each screw, accuracy of screw placement, and complication rate in the 3D-printing group were significantly superior to those in the control group. No patient experienced major complications. No significant correction loss or instrument dysfunction was observed during follow-up. CONCLUSIONS: As a viable and effective auxiliary technology, 3D printing makes it possible for surgery to meet both surgeon-specific and patient-specific requirements. 3D-printed individualized templates allow surgery for the correction of congenital scoliosis to enter a new stage of personalized precision surgery.

Three-Dimensional-Printed Individualized Guiding Templates for Surgical Correction of Severe Kyphoscoliosis Secondary to Ankylosing Spondylitis: Outcomes of 9 Cases.

OBJECTIVE: To report the outcomes of severe kyphoscoliosis secondary to ankylosing spondylitis (AS) corrected with 3D-printed individualized guiding templates. METHODS: Computed tomography (CT) data of patients with severe kyphoscoliosis secondary to AS were used to reconstruct 3D models of the spine and to develop a surgical plan. An asymmetric wedge pedicle subtraction osteotomy (PSO) was simulated using medical computer design software. Before the actual surgery, continual surgical simulations were performed until the most suitable one was obtained, and personalized guiding templates were manufactured for the anticipated PSO. During operation, the osteotomy plane and trajectories for the pedicle screws were positioned by the designed patient-specific 3D-printed guiding templates. RESULTS: In this study, we reviewed 9 patients who underwent correction of kyphoscoliosis using a 3D-printed individualized guiding template and were followed for a median of 21.4 months (range, 9-36 months). The average correction at the site of osteotomy was 65.9°. No patient experienced severe complications, such as misplaced pedicle screws or neurologic complications. At the last follow-up, no patient exhibited implant dysfunction on radiography. CONCLUSIONS: Preoperative surgical simulation using 3D-printed templates is a viable technique that enables surgery to meet both patient- and surgeon-specific requirements for correction of severe thoracolumbar kyphoscoliosis. These 3D-printed templates can guide the performance of planned PSO to provide functional restoration of severe kyphoscoliosis secondary to AS.

Pedicle screw fixation with kyphoplasty decreases the fracture risk of the treated and adjacent non-treated vertebral bodies: a finite element analysis.

Adjacent vertebral fractures are common in patients with osteoporotic vertebral compression fractures (OVCFs) after kyphoplasty. This finite element study was to examine whether short segment pedicle screw fixation (PSF) with kyphoplasty may decrease the fracture risk of the treated and adjacent non-treated vertebrae after kyphoplasty for OVCFs. By simulating cement augmentation with or without short segment pedicle screw fixation (PSF), two tridimensional, anatomically detailed finite element models of the T10-L2 functional spinal junction were developed. The insertion of pedicle screws into the intact vertebra apparently decreased the stress distribution of the treated vertebra in vertical compression and other load situations. The stress distribution in the bone structures of the intact vertebra adjacent to the intact-screwed vertebra was much less than that in the one adjacent to the treated vertebra. The insertion of pedicle screws into the intact vertebra greatly decreased the maximum displacement of the cortical bones and cancellous bones of the vertebrae. Our results indicated that short segment PSF with kyphoplasty may decrease the fracture risk of the treated and adjacent non-treated vertebrae in the management of OVCFs.

Computer-aided resection and endoprosthesis design for the management of malignant bone tumors around the knee: outcomes of 12 cases.

BACKGROUND: To report the outcomes of computer-aided resection and endoprosthesis design for the management of malignant bone tumors around the knee. METHODS: Computed tomography (CT) and magnetic resonance imaging (MRI) data were input into computer software to produce three-dimensional (3D) models of the tumor extent. Imaging data was then used to create a template for surgical resection, and development of an individualized combined allogeneic bone/endoprosthesis. Surgical simulations were performed prior to the actual surgery. RESULTS: This study included 9 males and 3 females with a mean age of 25.3 years (range, 13 to 40 years). There were 9 tumors in the distal femur and 3 in the proximal tibia. There were no surgical complications. In all cases pathologically confirmed clear surgical margins were obtained. Postoperative radiographs showed the range of tumor resection was in accordance with the preoperative design, and the morphological reconstruction of the bone defect was satisfactory with complete bilateral symmetry. The mean follow-up time was 26.5 months. Two patients died of their disease and the remaining are alive and well without evidence of recurrence. All patients are able to ambulate freely without restrictions. At the last follow-up, the average International Society of Limb Salvage score was 25.8 (range, 18 to 27), and was excellent in 8 cases and good in 4 cases. CONCLUSIONS: Computer-aided design and modeling for the surgical management of bone tumors and subsequent limb reconstruction provides accurate tumor removal with the salvage of a maximal amount of unaffected bone and precise endoprosthesis reconstruction.

[Preparation of cisplatin-impregnated coral hydroxyapatite drug delivery system].

OBJECTIVE: To prepare a cisplatin-impregnated coral-derived hydroxyapatite (CCHA) drug delivery system (DDS), and evaluate its inhibitory effect on human osteosarcoma cells U-2 OS, human breast cancer and prostatic carcinoma cells PC-3 in vitro. METHODS: The coral-derived hydroxyapatite (CHA) was manufactured by hydrothermal exchange and impregnated with cisplatin by vacuum freeze-drying techniques. The leaching solutions of this DDS was collected at different intervals in a course of 8 weeks and their inhibitory effect on the cells was tested in vitro by MTT assay. RESULTS: Electron microscope showed that cisplatin was distributed homogeneously in the pores of CHA. The inhibition rates of the leaching solution on all the tumor cells exceeded 50% except for PC-3 cells, whose inhibition rate was 29.92% when treated with the solution collected at the eighth week. CONCLUSION: CCHA allows sustained drug release and maintains excellent inhibitory effect on human bone tumor cells within 8 weeks in vitro.