A Review of the Benefits 3D Printing Brings to Patients with Neurological Diseases

Abstract

This interdisciplinary review focuses on how flexible three-dimensional printing (3DP) technology can aid patients with neurological diseases. It covers a wide variety of current and possible applications ranging from neurosurgery to customizable polypill along with a brief description of the various 3DP techniques. The article goes into detail about how 3DP technology can aid delicate neurosurgical planning and its consequent outcome for patients. It also covers areas such as how the 3DP model can be utilized in patient counseling along with designing specific implants involved in cranioplasty and customization of a specialized instrument such as 3DP optogenetic probes. Furthermore, the review includes how a 3DP nasal cast can contribute to the development of nose-to-brain drug delivery along with looking into how bioprinting could be used for regenerating nerves and how 3D-printed drugs could offer practical benefits to patients suffering from neurological diseases via polypill.

Keywords: 3D drug printing; bioprinting; implants; neurosurgery; personalized medicine.

Figure 1

Simulated surgery and intraoperative scenario. (A)Three-dimensional tumor model resection using left subtemporal keyhole approach and laser-knife. (B) Surgical simulation of removing the residual tumor on the 3D model from the petrous apex after rotation. (C) MRI scan at transverse position displaying tumor growth through middle-posterior cranial fossa preoperation. (D) Tumor observed in the coronal position, preoperation. (E) Real-patient tumor removal with laser-knife. (F) Intraoperation grinding of the petrous apexin. (G) Postoperation MRI scan showing no residual tumor after surgery in transverse view. (H) Coronal position confirming no tumor remaining post operation [24].

Figure 2

(A) Percentage of cases that changed surgical posture when looking at 3DP model of a brain tumor after MR images. The number of cases the surgeons treated before is shown against the percentage of change. (B) Percentage of cases that changed the degree of head rotation once presented with 3DP model of a brain tumor. (C) A flow diagram showing the implementation of 3DP model of a brain tumor in a clinical setting [27].

Figure 3

(A) ROBINS 3D image-reading software of patients’ skulls with defects. (B) Isolated cranial defect. (C) Polyurethan model used to make (D) cement moulds. (E) Moulds clamped together with titanium mesh in between. (F) Completed prosthetic with a specific contour for skull defect. (G) Patient’s head before cranioplasty indicating cranial defects in frontal regions. (H) Patient’s head after customized titanium implant, presenting improved aesthetic outcome due to restoration of calvarium contour [12].

Figure 4

(a) Image demonstrates the customizability in terms of scale, allowing for various mammalian brains to use 3D-printed optogenetic probes (3DP-OPs). (b) Design and architecture of 3DP-OPs. (c) Manufacturing sets of 3DP-Ops: (①) printing probe via SLA, (②) removal of probe and washing off excess residue, (③) application of silver paste to microgroove surface of probe and transverse the surface longitudinally with a rubber blade, (④) attaching microscale inorganic light emitting diode (µ-ILED) to probe tip. (d) Optical images indicating customizability in structural design and different colored µ-ILEDs. (e) Printed 3DP-OPs showing different lengths (f) Thickness of the 3DP-OPs (yellow) against that of a human hair (blue). (g) Flexibility of the 3DP-OPs, which are wrapped around a 1.5 mm rod [6].

Figure 5

The drug-release profile of each drug from the compartments in the polypill in vitro [50].