The Barrow Biomimetic Spine: Face, Content, and Construct Validity of a 3D-Printed Spine Model for Freehand and Minimally Invasive Pedicle Screw Insertion

Expanding Clinician Access to High-Quality, Low-Cost Biomechanical Research: A Technical Report on the Carolina Neurosurgery and Spine Biomechanics Laboratory

Spine biomechanical research helps us better understand the spine in physiologic and pathologic states and gives us a mechanism by which to evaluate surgical interventions, generate and evaluate models of spine pathologies, and develop novel, data-driven surgical strategies and devices. Access to a biomechanical testing laboratory is therefore potentially invaluable to those who specialize in treating spine pathologies. A number of barriers to access have precluded many clinicians from pursuing their biomechanical research interests, foremost among these is cost. The Carolina Neurosurgery and Spine Biomechanics Research Laboratory (CNSBL) was developed as a model of a low-cost, easy-to-access laboratory capable of generating high-quality data in tests of axial load, tension, torque, displacement, and pathological model testing. Our experience in developing this laboratory suggests that a large number of basic biomechanical research inquiries can be studied in a laboratory composed of less than $7500 USD of hardware. We hope that this model serves as a roadmap for any like-minded practitioners seeking broader access to biomechanical testing facilities.

Properties and Implementation of 3-Dimensionally Printed Models in Spine Surgery: A Mixed-Methods Review With Meta-Analysis

OBJECTIVE

Spine surgery addresses a wide range of spinal pathologies. Potential applications of 3-dimensional (3D) printed in spine surgery are broad, encompassing education, planning, and simulation. The objective of this study was to explore how 3D-printed spine models are implemented in spine surgery and their clinical applications.

METHODS

Methods were combined to create a scoping review with meta-analyses. PubMed, EMBASE, the Cochrane Library, and Scopus databases were searched from 2011 to 7 September 2021. Results were screened independently by 2 reviewers. Studies utilizing 3D-printed spine models in spine surgery were included. Articles describing drill guides, implants, or nonoriginal research were excluded. Data were extracted according to reporting guidelines in relation to study information, use of model, 3D printer and printing material, design features of the model, and clinical use/patient-related outcomes. Meta-analyses were performed using random-effects models.

RESULTS

Forty articles were included in the review, 3 of which were included in the meta-analysis. Primary use of the spine models included preoperative planning, education, and simulation. Six printing technologies were utilized. A range of substrates were used to recreate the spine and regional pathology. Models used for preoperative and intraoperative planning showed reductions in key surgical performance indicators. Generally, feedback for the tactility, utility, and education use of models was favorable.

CONCLUSIONS

Replicating realistic spine models for operative planning, education, and training is invaluable in a subspeciality where mistakes can have devastating repercussions. Future study should evaluate the cost-effectiveness and the impact spine models have of spine surgery outcomes.

Utility of 3-dimensionally printed models for parent education in pediatric plagiocephaly

Objectives

Demonstrate the benefits of using 3D printed skull models when counseling families regarding disorders of the cranial vault (namely plagiocephaly and craniosynostosis), as traditional imaging review and discussion is often insufficient.

Methods

3D printed skull models of a patient with plagiocephaly were used during clinic appointments to aid in the counseling of parents. Surveys were distributed following the appointment to evaluate the utility of these models during the discussion.

Results

Fifty surveys were distributed (with a 98% response rate). 3D models were both empirically and anecdotally helpful for parents in understanding their child's diagnosis.

Conclusion

Advances in 3D printing technology and software have made producing models more accessible. Incorporating physical, disorder-specific models into our discussions has led to improvements in our ability to communicate with our patients and their families.

Innovation

Disorders of the cranial can be challenging to describe to the parents and guardians of affected children; using 3D printed models is a useful adjunct in patient-centered discussions. The subject response to the use of these emerging technologies in this setting suggests a major role for 3D models in patient education and counseling for cranial vault disorders.

3D-Printed Disease Models for Neurosurgical Planning, Simulation, and Training

Spatial insight into intracranial pathology and structure is important for neurosurgeons to perform safe and successful surgeries. Three-dimensional (3D) printing technology in the medical field has made it possible to produce intuitive models that can help with spatial perception. Recent advances in 3D-printed disease models have removed barriers to entering the clinical field and medical market, such as precision and texture reality, speed of production, and cost. The 3D-printed disease model is now ready to be actively applied to daily clinical practice in neurosurgical planning, simulation, and training. In this review, the development of 3D-printed neurosurgical disease models and their application are summarized and discussed.

Utility of a Novel Biomimetic Spine Model in Surgical Education: Case Series of Three Cervicothoracic Kyphotic Deformities

STUDY DESIGN

Evaluation of new technology.

OBJECTIVES

To evaluate the utility of a novel biomimetic spine model as a surgical planning and education resource in the treatment of cervical spine deformities (CSD).

METHODS

Three patients with CSD were identified and synthetic spine models were manufactured to match the anatomical and biomechanical properties of each patient. Each model underwent 3 phases of surgical correction: maximum correction with no osteotomies performed, with posterior column osteotomies (PCOs) only, and with PCOs and a 3-column osteotomy (3CO). Lateral fluoroscopic films were obtained after each phase of correction for measurement of cervical lordosis. Surgeons were surveyed to obtain subjective feedback on the perceived model utility.

RESULTS

Each model began with a kyphotic deformity that was mobile, rigid, or fixed. The mobile model achieved successive lordotic correction with each phase of correction. The rigid and fixed models achieved much less correction with no osteotomies and PCOs only, and the majority of correction with 3COs. Each model predicted with varying, but overall high, accuracy the amount of correction achieved in each patient. The surgeons felt the model had very high utility as a surgical education platform.

CONCLUSIONS

The models appeared to accurately replicate the gross anatomy and biomechanical performance of the patients' spines. This high fidelity to the individual patient's anatomy, bone quality, and segmental mobility resulted in a custom model that provides an invaluable learning platform for surgical education. These results suggest the models may have utility in surgical planning, but further studies are needed.

The Living Spine Model: A Biomimetic Surgical Training and Education Tool

BACKGROUND

The Living Spine Model (LSM) is a three-dimensionally printed, surgical training platform developed by neurosurgical residents.

OBJECTIVE

To evaluate the face and content validity of this model as a training tool for open posterior lumbar surgery.

METHODS

Six surgeons with varying experience were asked to complete L3-5 pedicle screw fixation and L3-4 laminectomy on an LSM. Face validity was measured using a questionnaire, and content validity was measured using the National Aeronautics and Space Administration Task Load Index (NASA TLX) tests. Student's t-test was used to compare NASA TLX responses between junior and senior residents and to compare responses for live surgery vs simulated surgery on the LSM.

RESULTS

Junior residents took the longest time to complete the procedure, followed by senior residents and the attending surgeon (136.5, 98.3, and 84 min, respectively). The junior residents placed fewer successful pedicle screws (7/12) than senior residents and attending surgeon (18/18). All tested components of the model had excellent face validity, with scores ranging from 60% to 97%. Content validity testing demonstrated that the LSMs created overall workloads and specific types of work like live operating conditions.

CONCLUSION

The overall validity testing of the LSM demonstrates the high-potential utility of this model as a surgical education and testing platform for open posterior lumbar procedures. The LSM has great potential as an adjunct to surgical education, and it may become an increasingly important component of surgical resident curricula in the future.

Development and first clinical use of a novel anatomical and biomechanical testing platform for scoliosis

BACKGROUND

Previous studies have demonstrated that, by using various three-dimensional (3D) printing technologies, synthetic spine models can be manufactured to mimic a human spine in its gross and radiographic anatomy and the biomechanical performance of bony and ligamentous tissue. These manufacturing processes have not, however, been used in combination to create a long-segment, biomimetic model of a patient with scoliosis. The purpose of this study was to describe the development of a biomimetic scoliosis model and early clinical experience using this model as a surgical planning and education platform.

METHODS

Synthetic spine models were printed to mimic the anatomy and biomechanical performance of 2 adult patients with scoliosis. Preoperatively, the models were surgically corrected by the attending surgeon of each patient. Patients then underwent surgical correction of their spinal deformities. Correction of the models was compared to the surgical correction in the patients.

RESULTS

Patient 1 had a preoperative coronal Cobb angle of 40° from L1 to S1, as did the patient's synthetic spine model. The patient's spine model was corrected to 17.6°, and the patient achieved a correction of 17.3°. Patient 2 had a preoperative mid-thoracic Cobb angle of 88° and an upper thoracic Cobb angle of 43°. Preoperatively, the patient's spine model was corrected to 19.5° and 9.2° for the mid-thoracic and upper thoracic curves, respectively. Immediately after surgery, the patient's mid-thoracic and upper thoracic Cobb angles measured 18.7° and 9.5°, respectively. In both cases, the use of the spine models preoperatively changed the attending surgeon's operative plan.

CONCLUSIONS

A novel synthetic spine model for corrective scoliosis procedures is presented, along with early clinical experience using this model as a surgical planning platform. This model has tremendous potential not only as a surgical planning platform but also as an adjunct to patient consent, surgical education, and biomechanical research.