In the teaching and training, 3D printing can meet the large demand of specimens, make up for the shortage of human tissue specimens, and carry out highly targeted simulation teaching for different lesions. At the same time, it is cleaner than human specimens, with unique advantages and broad prospects.
2.2 Application of 3D printing in skull repair materials
3D printed cranial repair materials have achieved good clinical application results.KIM et al. took advantage of 3D printing technology and adopted PMMA as the repair material. Before surgery, they modeled the skull CT scan data, printed the skull model, and implanted the skull defect site, achieving a very perfect repair effect.At the same time, even a simple 3D printer can print repair materials well, and has the advantage of low cost.
At present, the most widely used 3D printing repair materials in China are PEEK, especially for patients with skull defects after craniofacial complex trauma. Compared with traditional titanium mesh repair materials, 3D printing has higher precision and better histocompatibility.
2.3 Application of 3D printing technology in cerebrovascular surgery
Cerebrovascular disease surgery is a risky and difficult neurosurgical operation with high disability rate and fatality rate.Before surgery, physicians need to fully interpret the imaging data in order to achieve a profound understanding of the intraoperative anatomy, which traditionally depends on the physician’s own good spatial imagination.In the past few decades, the imaging diagnosis of cerebrovascular diseases has evolved from 2D angiography to 3D and even 4D angiography. Although 3D image reconstruction technology can help surgeons understand the anatomical details of diseases to some extent, it is difficult to provide a more practical surgical experience.
3D printing of cerebrovascular disease model can perfectly solve this problem. The disease model can not only be viewed from any Angle to simulate the anatomical orientation during the operation, but also can be touched and operated to simulate the actual operation process realistically, which is a more favorable visualization method.For aneurysm clipping surgery, it is essential to fully understand the shape, orientation, aneurysmal neck and the relationship between aneurysm and adjacent artery and its branches, brain tissue, cranial nerve and skull.The selection and adjustment of aneurysm clip is also one of the difficulties in complicated aneurysm surgery.
Since D ‘Urso et al reported the application of 3D printing technology in intracranial aneurysms and arteriovenous malformation for the first time, dozens of articles on the application of 3D printing aneurysm models have been published in domestic and foreign journals.In addition to surgical operations, 3D printing is also used in the interventional treatment of aneurysms. NAMBA et al. reported that they successfully performed aneurysm embolization for 10 patients by using this technology to assist microcatheter shaping.The 3D-printed aneurysm model can not only help surgeons better understand the details of aneurysms, simulate the clamping and select aneurysm clips before surgery, but also be used for preoperative doctor-patient communication to help patients understand aneurysm disease and facilitate smooth communication.In terms of arteriovenous malformations, accurate 3D models can significantly improve surgical planning and improve the probability of good prognosis.
Relevant studies reported that: in preoperative cases of arteriovenous malformation using 3D printing, the operation time was significantly shortened, which again indicated that the printing model was helpful for the operation planning and implementation.Arteriovenous malformations reported by 3D printing are less than aneurysms. The main reason is that the vascular anatomy of arteriovenous malformations is more complex, the changeable supplying arteries and draining veins, the malformations themselves are mixed with brain tissues, and the malformed vessels are scattered, etc., which all cause the difficulties of 3D printing.High precision 3D modeling and printing techniques, which are still under development, may improve their application in cerebrovascular malformations.
2.4 Application of 3D printing in skull base tumors
The location of skull base tumor is deep, the anatomy is complex and the function is important.In the field of transsphenoidal endoscopic sellar region tumor resection, it is the first to apply 3D printing to the development of simulated surgery.In relevant studies, a 3D-printed skull model has been created for preoperative evaluation of endoscopic sellar region surgery.The model can be registered in the surgical navigation system, which can reflect the surgical process more accurately. Moreover, the model can be matched with the corresponding neural images in real time, providing more intuitive simulation experience, which is one of its important advantages.
MULLER et al. showed that compared with 3D printing for preoperative evaluation of complex skull base lesions, conventional imaging alone had a poor preoperative evaluation effect.The 3D printed model can accurately simulate the anatomy of complex skull base tumors, simulate skull grinding before surgery, help to understand the relationship between neurovascular and lesions, and is suitable for highly individualized planning of complex skull base surgery.
2.5 Application of 3D printing in spinal cord surgery
Spinal cord is an important branch of neurosurgery, but the treatment of spinal cord diseases carried out by neurosurgery in China is mostly limited to spinal tumor surgery, one of the main reasons is that the relevant anatomical structure is not familiar with.3D printed models can better solve this problem by simulating the spinal anatomy, making complex spinal fractures, pedicle screw fixation and other complex spinal surgeries easier.SUGAWARA et al. designed a personalized multi-step screw guide that could be locked on the vertebral plate to prevent wrong movement. They performed surgery and evaluation on 10 patients and found that the fixed mean deviation was < 1mm.
In addition, 3D printing technology also solves the surgical technique problem of spinal surgery.At present, scientists at home and abroad are beginning to explore the application of 3D printing technology in tissue engineering solutions for disc degeneration, in the hope of using 3D printing technology to regenerate intervertebral discs, thus replacing spinal fusion and artificial intervertebral disc replacement. However, further research is needed to produce clinically usable implants.
2.6 Application of biological 3D printing in neurosurgery
The application scenarios of bio-printing technology include tissue engineering and regenerative medicine, pharmacy and drug screening, cancer research, etc. At present, it has been able to carry out bio-printing for a variety of tissue types, but the printed tissue is mostly limited to thin, hollow or non-vascular tissue, which still has great limitations.Recently, with the maturity of vascular network bio-printing, it is possible to print larger, bioactive tissues and organs.Despite the great progress in bio-printing research, its clinical applicability still lags behind and there is still a long way to go.
The U.S. Food and Drug Administration has approved several tissue-engineered skin substitutes for the healing of large wounds.Applications for 3D-printed bio-grafts in neurosurgery are still a long way off.In the future, to expect applied in neurosurgery biological printing organization with scalp transplantation and vascular printing, such as for large complex aneurysms, vascular replacement is the only method can thoroughly solve the problem, the 3 d biological blood vessels printing compatibility can provide better and more matching, branch pipe diameter more in line with the physical condition of blood vessels, to replace the current application of radial artery.In clinical practice, resin materials can be used to achieve the replacement of large vessels or hollow vessels, but bioactive vascular replacement materials are still being explored.