Introduction: Current spinal immobilization technologies are inadequate for treating spinal injuries because they are designed to have a degree of extension due to the axis of rotation being anterior with fixation on the under-surface of the chin. Forced extension is counterproductive in injuries that require optimal volume area in the cervical spinal canal and space at the neural foramina for spinal nerves to exit the spinal cord.

Methods: Current limitations of existing cervical collars were identified: pain and pressure; noncompliance; poor immobilization of axial spine; and axial muscle atrophy. Furthermore; patient characteristics that limit a collar's effectiveness were identified: cervical deformity; obese or long thin necks; pediatric population; atrophy; and incisions. A novel two-piece design was proposed for the shell with custom fixation points based off of a patient's MRI or CT scan and a third inner insert that could accommodate for atrophy as well as aligning the neck so the maximum space is available for the cord. Mimics software was used for additive manufacturing and 3D printing.

Results: 3D model of patient's spine and soft tissue could reliably be created and ideal alignment achieved on software with a formula built upon space available for the cord or fracture alignment to determining the amount of flexion or extension the patient should be placed in. A case of a 26 yo M with unilateral facet fracture who failed conservative management with standard orthotic showed only 40% limitation of movement in sagittal plane; where as, a custom printed collar aligning his facets showed 90% reduction of movement with greater comfort score.

Conclusions: Our cervical collar design allows the spine to be more effectively stabilized than the current standard of external cervical orthotics. Highlights include minimizing soft tissue for immobilization and adjusting the axis of rotation and segments immobilized to be customized for a patient's individual pathology.

Patient Care: 1)Provide a patient-specified custom cervical orthesis through advanced additive manufacturing methods where fabrication lead time is reduced to hours compared to days and weeks for other similar body orthesis. 2) Increased patient compliance of set posture and movement due to improved fit and feel 3) Capability to replace custom contoured insert over the course of treatment with replacements that take into consideration muscle atrophy and changes over time that lead to poor immobilization 4)Reduced nerve root and spinal irritation/compression by maximizing volume for the neural elements 5) Alternative to surgery by aiding in fracture alignment for healing. 6) Improved functional recovery and less secondary injury in patients with hyperextension injuries resulting in cervical spinal cord injury 7) Provide improved immobilization of capital flexion and extension for higher cervical spine pathology (CO-C1), providing an alternative to more invasive halo immobilization 8) Provide alternative to surgery in patients who do not want surgery, could not tolerate surgery due to medical co-morbidities, or for which surgery is contraindicated 9) Provide an improved post-operative adjunct to patients undergoing fusion surgery by allowing the surgeon to immobilize a patient in slight flexion so that compression-osteogenesis does not occur (optimal positioning for healing)

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the limitations of current cervical orthotics 2) Identify the benefits of custom printed cervical collars that are able to align the spine to specific patient parameters 3) Discuss the future of additive manufacturing and 3D printing in Neurosurgery

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