Objective
To review the current research progress of three-dimensional (3-D) printing technique in foot and ankle surgery.
Methods
Recent literature associated with the clinical application of 3-D printing technique in the field of medicine, especially in foot and ankle surgery was reviewed, summarized, and analyzed.
Results
At present, 3-D printing technique has been applied in foot and ankle fracture, segmental bone defect, orthosis, corrective surgery, reparative and reconstructive surgery which showed satisfactory effectiveness. Currently, there are no randomized controlled trials and the medium to long term follow-up is necessary.
Conclusion
The printing materials, time, cost, medical ethics, and multi-disciplinary team restricted the application of 3-D printing technique, but it is still a promising technique in foot and ankle surgery.
ObjectiveTo construct large block of engineered liver tissue by co-culture of fibroblasts and hepatocytes on collagen hydrogels in vitro and do in vivo implantation research.
MethodsSilastic mould was prepared using three-dimensional printing technology. The collagen hydrogel scaffold was prepared by collagen hydrogel gel in the silicone mould and was removed. Sprague Dawley rat lung fibroblasts were co-cultured with primary hepatocytes at a ratio of 0.4:1 on the collagen hydrogel scaffold to construct large block of engineered liver tissue in vitro (group B), and primary hepatocytes cultured on the collagen hydrogel scaffold served as control group (group A). The cell morphology was observed, and the liver function was tested at 1, 3, 7, 14, and 21 days after culture. The rat model (n=24) of hepatic cirrhosis was made by subcutaneous injection of carbon tetrachloride. And in vivo implantation study was carried in cirrhosis rat model. The phenotypic characteristics and functional expression of hepatocytes were evaluated at 3, 7, 14, 21, and 28 days after implantation.
ResultsIn vitro results indicated that hepatocytes in group B exhibited compact polyhedral cells with round nuclei and high expression of liver function. Moreover, cells aggregated to the most at 7 days. Album production and urea synthesis incresed significantly when compared with group A (P<0.05). In vivo results showed hepatocytes in group B survived for 28 days, and albumin production and urea synthesis were significantly increased. In addition, hepatocytes showed an aggregated distribution and cord-like structures, which was similar to normal liver tissue.
ConclusionThe large block of engineered liver tissue constructed by co-cultured cells can form tissue similar to normal liver tissue in vivo, and survive for a long time, laying foundations for building more complete engineered liver tissue in the future.
ObjectiveTo evaluate the clinical significance of individualized reference model of sagittal curves by three-dimensional (3D) printing technique and computer-aided navigation system for lumbar spondylolisthesis.
MethodsBetween February 2011 and October 2012, 66 patients with lumbar spondylolisthesis underwent posterior lumbar interbody fusion (PLIF) by traditional operation in 36 cases (control group) and by individualized reference model of sagittal curves by 3D printing technique and computer-aided navigation system in 30 cases (trial group). There was no significant difference in gender, age, disease duration, segment, type of disease, degree of spondylolisthesis, and preoperative the visual analogue scale (VAS) of low back pain and leg pain between 2 groups (P>0.05). The operation time, blood loss, fluoroscopy times, VAS score of low back pain and leg pain were compared between 2 groups; the sagittal screw angle (SSA), accuracy rate of pedicle screw, Taillard index, disc height recovery rate, and sagittal angle recovery rate were compared between 2 groups.
ResultsThere was no significant difference in operation time and blood loss between 2 groups (P>0.05). But fluoroscopy times of control group were significantly higher than those of trial group (P<0.05). One case had radicular symptoms after operation in control group. The patients of 2 groups were followed up 24-36 months (mean, 26 months). The VAS scores of low back pain and leg pain at last follow-up were significantly better than pre-operative scores in 2 groups (P<0.05); VAS score of low back pain in trial group at last follow-up was significantly lower than that in control group (P<0.05). The accuracy rate of pedicle screw was 81.9% (118/144) in control group and 91.7% (110/120) in trial group, showing significant difference (χ2=5.25, P=0.03). There was significant difference in SSA between 2 groups at immediate after operation (t=-6.21, P=0.00). At immediate after operation and last follow-up, Taillard index, disc height recovery rate, and sagittal angle recovery rate in trial group were significantly better than those in control group (P<0.05).
ConclusionPLIF by individualized reference model of sagittal curves by 3D printing technique and computer-aided navigation system can effectively correct spondylolisthesis, recover the lumbar sagittal angle and improve the VAS score of low back pain though it has similar operation time and blood loss to traditional PLIF.
ObjectiveTo evaluate the clinical significance of individualized reference model of sagittal curves and navigation templates of pedicle screw by three-dimensional printing technique for thoracolumbar fracture with dislocation.
MethodsBetween February 2011 and November 2013, 42 patients with thoracolumbar fracture and dislocation undergoing pedicle screw fixation were divided into 2 groups:traditional pedicle screw internal fixation by fluoroscopy assistant was used in 24 cases (control group), and individualized reference model of sagittal curves and navigation templates of pedicle screw were used in 18 cases (trial group). There was no significant difference in gender, age, injury causes, segment, degree of dislocation, and Frankel classification between 2 groups (P>0.05). The operation time, intraoperative blood loss, perspective times, and dislocation rate, sagittal angle recovery rate at different time were compared. The success rate of pedicle screw insertion, sagittal screw angle, and Frankel classification were compared. The angle between sagittal screws, difference of screw entry point at horizontal position, and difference of screw inclined angle were compared.
ResultsThe operating time, intraoperative blood loss, and perspective times in trial group were significantly lower than those in control groups (P<0.05). All the patients were followed up 12-40 months (mean, 22 months). The dislocation rate at immediate after operation and last follow-up were significantly improved when compared with preoperative value in 2 groups (P<0.05). At immediate after operation and last follow-up, the dislocation rate and sagittal angle recover rate in trial group were significantly better than those in control group (P<0.05). There were significant differences in the one-time success rate, final success rate of pedicle screw insertion, and saggital screw angle between 2 groups (χ2=9.38, P=0.00; χ2=10.95, P=0.00; χ2=13.43, P=0.00). The angle between sagittal screws, difference of screw entry point at horizontal position, and difference of screw inclined angle in trail group were significantly less than those in control group (P<0.05). There was significant difference in the Frankel classification between 2 groups at last follow-up (Z=-1.99, P=0.04).
ConclusionThe application of individualized reference model of sagittal curves and navigation templates of pedicle screw by three-dimensional printing technique for thoracolumbar fracture with dislocation has the advantages of shorter operation time, less intraoperative blood loss, better recovery of thoracolumbar dislocation, and better Frankel classification.
ObjectiveTo improve the poor mechanical strength of porous ceramic scaffold, an integrated method based on three-dimensional (3-D) printing technique is developed to incorporate the controlled double-channel porous structure into the polylactic acid/β-tricalcium phosphate (PLA/β-TCP) reinforced composite scaffolds (double-channel composite scaffold) to improve their tissue regeneration capability and the mechanical properties.
MethodsThe designed double-channel structure inside the ceramic scaffold consisted of both primary and secondary micropipes, which parallel but un-connected. The set of primary channels was used for cell ingrowth, while the set of secondary channels was used for the PLA perfusion. Integration technology of 3-D printing technique and gel-casting was firstly used to fabricate the double-channel ceramic scaffolds. PLA/β-TCP composite scaffolds were obtained by the polymer gravity perfusion process to pour PLA solution into the double-channel ceramic scaffolds through the secondary channel set. Microscope, porosity, and mechanical experiments for the standard samples were used to evaluate the composite properties. The ceramic scaffold with only the primary channel (single-channel scaffold) was also prepared as a control.
ResultsMorphology observation results showed that there was no PLA inside the primary channels of the double-channel composite scaffolds but a dense interface layer between PLA and β-TCP obviously formed on the inner wall of the secondary channels by the PLA penetration during the perfusion process. Finite element simulation found that the compressive strength of the double-channel composite scaffold was less than that of the single-channel scaffold; however, mechanical tests found that the maximum compressive strength of the double-channel composite scaffold[(21.25±1.15) MPa] was higher than that of the single-channel scaffold[(9.76±0.64) MPa].
ConclusionThe double-channel composite scaffolds fabricated by 3-D printing technique have controlled complex micropipes and can significantly enhance mechanical properties, which is a promising strategy to solve the contradiction of strength and high-porosity of the ceramic scaffolds for the bone tissue engineering application.
ObjectiveTo summarize the current research progress of three-dimensional (3D) printing technique for spinal implants manufacture.
MethodsThe recent original literature concerning technology, materials, process, clinical applications, and development direction of 3D printing technique in spinal implants was reviewed and analyzed.
ResultsAt present, 3D printing technologies used to manufacture spinal implants include selective laser sintering, selective laser melting, and electron beam melting. Titanium and its alloys are mainly used. 3D printing spinal implants manufactured by the above materials and technology have been successfully used in clinical. But the problems regarding safety, related complications, cost-benefit analysis, efficacy compared with traditional spinal implants, and the lack of relevant policies and regulations remain to be solved.
Conclusion3D printing technique is able to provide individual and customized spinal implants for patients, which is helpful for the clinicians to perform operations much more accurately and safely. With the rapid development of 3D printing technology and new materials, more and more 3D printing spinal implants will be developed and used clinically.
ObjectiveTo explore the application of three-dimensional (3-D) printing technique in repair and reconstruction of maxillofacial bone defect.
MethodsThe related literature on the recent advance in the application of 3-D printing technique for repair and reconstructing maxillofacial bone defect was reviewed and summarized in the following aspects:3-D models for teaching, preoperative planning, and practicing; surgical templates for accurate positioning during operation; individual implantable prosthetics for repair and reconstructing the maxillofacial bone defect.
Results3-D printing technique is profoundly affecting the treatment level in repair and reconstruction of maxillofacial bone defect.
Conclusion3-D printing technique will promote the development of the repair and reconstructing maxillofacial bone defect toward more accurate, personalized, and safer surgery.
ObjectiveTo investigate the clinical application of three-dimensional (3D) printing technique combined with a new type of thoracic pedicle screw track detector in thoracic pedicle screw placement.MethodsAccording to the characteristics of thoracic pedicle and common clinical screw placement methods, a new type of thoracic pedicle screw track detector was independently developed and designed. The clinical data of 30 patients with thoracic vertebrae related diseases who underwent posterior thoracic pedicle screw fixation between March 2017 and January 2020 were retrospectively analysed. Among them, there were 18 males and 12 females with an average age of 56.3 years (range, 32-76 years). There was 1 case of thoracic disc herniation, 4 cases of thoracic canal stenosis, 2 cases of ossification of posterior longitudinal ligament of thoracic vertebra, 16 cases of thoracic trauma, 2 cases of thoracic infection, and 5 cases of thoracic canal occupation. Three-dimensional CT of the thoracic vertebra was routinely performed preoperatively, and the model of the patient’s thoracic vertebra was reconstructed and printed out. With the assistance of the model, preoperative simulation was performed with the combination of the new type thoracic pedicle screw track detector, and detected no nails after critical cortical damage. During operation, one side was randomly selected to use traditional hand screws placement (control group), and the other side was selected to use 3D printing technique combined with new type thoracic pedicle screw track detector to assist thoracic pedicle screws placement (observation group). The single screw placement time, adjustment times of single screw, and blood loss during screw placement were compared between the two groups. The accuracy of screw placement in the two groups was evaluated according to postoperative CT imaging data.ResultsThe single screw placement time, adjustment times of single screw, and blood loss during screw placement in the observation group were significantly less than those in the control group (P<0.05). Postoperative CT examination showed that the observation group had 87 screws of grade 1, 3 screws of grade 2, and the acceptable screw placement rate was 100% (90/90); the control group had 76 screws of grade 1, 2 screws of grade 2, 11 screws of grade 3, and 1 screw of grade 4, and the acceptable screw placement rate was 86.7% (78/90); showing significant difference in screw placement between the two groups (χ2=12.875, P=0.001). All patients were followed up 6-18 months, with an average of 11.3 months. There was no complication of vascular, nerve, spinal cord, or visceral injury, and screws or rods broken, and no patient was revised.ConclusionThe 3D printing technique combined with the new type of thoracic pedicle screw track detector assisted thoracic pedicle screw placement is convenient, and significantly improves the accuracy and safety of intraoperative screw placement, and overall success rate of the surgery.
ObjectiveTo review the current progress of three-dimensional (3-D) printing technique in the clinical practice, its limitations and prospects.
MethodsThe recent publications associated with the clinical application of 3-D printing technique in the field of surgery, especially in orthopaedics were extensively reviewed.
ResultsCurrently, 3-D printing technique has been applied in orthopaedic surgery to aid diagnosis, make operative plans, and produce personalized prosthesis or implants.
Conclusion3-D printing technique is a promising technique in clinical application.
ObjectiveTo review the current research status of in situ three-dimensional (3-D) printing technique and future trends.
MethodsRecent related literature about in situ 3-D printing technique was summarized, reviewed, and analyzed.
ResultsBased on the cl inical need for surgical repair, in situ 3-D printing technique is in the preliminary study, mainly focuses on in situ dermal repair and bone and cartilage repair, and succeeds in experiments, but there are still a lot of problems for cl inical application.
ConclusionWith the development of in situ 3-D printing technique, it will provide patients with real-time and in situ digital design and 3-D printing treatment with a timely and minimally invasive surgical repair process. It will be widely used in the future.
