Altair > Case Studies > Solid Hex Meshing the Human Lumbar Spine: A Case Study on NuVasive Inc.

Solid Hex Meshing the Human Lumbar Spine: A Case Study on NuVasive Inc.

Technology Category

Platform as a Service (PaaS) - Device Management Platforms
Wearables - Implants

Applicable Industries

Equipment & Machinery
Healthcare & Hospitals

Applicable Functions

Product Research & Development
Quality Assurance

Use Cases

Virtual Prototyping & Product Testing
Virtual Reality

Services

Testing & Certification

About The Customer

NuVasive Inc., based in San Diego, California, is a medical device company focused on the design, development and marketing of products for the surgical treatment of spine disorders. Ranking no. 3 in the US spine industry, they specialize in minimally disruptive surgical procedures and are the pioneers of lateral access spine surgery with eXtreme Lateral Interbody Fusion (XLIF®). Through innovative technological advancements, NuVasive has successfully progressed major spine surgery to where many patients have experienced extraordinary results—they are often walking the same day of surgery, experiencing reduced blood loss, spending less time in the hospital, and being able to return to work within four to six weeks (versus the traditional six months).

The Challenge

The challenge faced by NuVasive Inc., a medical device company specializing in the surgical treatment of spine disorders, was to predict how a device will perform while ensuring they are safe and effective, before a single prototype is built. The company wanted to leverage computational modeling and simulation to eliminate bad ideas and refine the good ones long before they leave the drawing board. The objective of this project was to take anatomic geometry obtained from a CT scan and develop a finite element model that could evaluate the biomechanical stability of different interbody cage footprints that is typically performed using cadaveric testing. Since bone geometry is unique to each individual, and bones are not symmetric, a manual hexahedral (HEXA) meshing approach needed to be established in order to build models with a repeatable process.

The Solution

The solution was pre-processing with HyperMesh. The vertebral bodies of the lumbar spine needed to be hex meshed and seamlessly connected to the posterior region using tetra elements. This would allow for a uniform mesh between the vertebral bodies and the intervertebral discs. Creating hex elements instead of standard tetra elements in the intervertebral body and discs allowed quicker run times. NuVasive looked at different software options in the market that could help them build such a model quickly and efficiently. With the solid meshing capabilities of HyperMesh and its powerful morphing tool they were able to quickly model the lumbar, while satisfying their analysis requirements. The manual HEXA meshing approach process included the use of HyperMorph module to project elements onto geometry in exact areas. This was a customized process using the existing tools in HyperMesh to fit the customer’s needs in this unique application.

Operational Impact

NuVasive’s use of HyperMesh to HEXA mesh human vertebrae is now routinely used within their structural simulation department. They are currently using computational modeling using HyperMesh to anticipate the performance of medical devices when they are used in various patient groups. By providing these new finite element analysis (FEA) models to device engineers, they are ensuring cutting-edge devices are safe and effective, and that they can reach the physicians and patients as quickly as possible. The typical run times of simulation have been reduced from almost 12 hrs to only 4 hrs due to the effective modeling in HyperMesh. This also helps them internally to predict the biomechanical behavior and stability of the lumbar spine model. They are also able to effectively predict stresses induced in human lumbar spine with the introduction of meshed implants which gives them an overall understanding of the system. With the current modeling process, NuVasive is able to streamline the model more efficiently with shorter run times, pair up multiple designs quickly and check for stability of implants.

Quantitative Benefit