When people think of pythons, the image of a large snake constricting its prey often comes to mind. However, researchers have discovered that pythons initially grasp their prey with sharp teeth that curve backward. These teeth are ideal for holding onto soft tissue without causing damage. Dr. Stavros Thomopoulos, a professor of orthopedics and biomedical engineering at Columbia University, has been exploring the idea of mimicking these teeth in surgical procedures.
Innovative Approach
Dr. Thomopoulos, a leading expert in tendon-to-bone attachment development, has been focusing on improving tendon-to-bone repair, crucial for procedures like rotator cuff repair and anterior cruciate ligament reconstruction. In a recent study published in Science Advances, his team introduced a python-tooth-inspired device to enhance current rotator cuff suture repair, resulting in nearly double the repair strength.
“As we age, a significant portion of the population will experience a rotator cuff tear, leading to pain and reduced mobility,” said Dr. Thomopoulos. “While rotator cuff surgery is the best treatment option, a concerning number of repair procedures fail shortly after. Our biomimetic approach, inspired by python teeth, aims to securely reattach tendons to bones. This device not only strengthens the repair but can also be tailored to individual patients, offering great potential in improving rotator cuff injury care.”
Rotator Cuff Challenges
Rotator cuff tears are among the most common tendon injuries, affecting over 17 million Americans annually. The incidence of these injuries rises with age, with more than 40% of individuals over 65 experiencing a tear.
Given that rotator cuff tears often occur at the tendon-to-bone insertion site, surgical repair focuses on anatomically restoring the tendon attachment. Despite more than 600,000 rotator cuff surgeries performed in the US each year, amounting to $3 billion in costs, successfully reconnecting the tendon to the bone remains a significant challenge.
Current techniques involve sutures that can lead to high failure rates due to tearing through the tendon at stress points during movement. This issue, known as “suture pull-through” or “cheesewiring,” often results in the failure of the repair, especially in elderly patients with substantial tears.
While there have been advancements in rotator cuff repair methods, the fundamental practice of sewing tissues together remains largely unchanged, relying on sutures to transfer tension at high-stress points. However, these sutures can fail, causing the tendon to tear at these points of high stress after surgery.
“Our goal was to create a device inspired by python teeth to grasp soft tissues effectively without causing tears, reducing the risk of re-tearing the tendon post rotator cuff repair,” said Iden Kurtaliaj, the lead researcher on the study.
The Innovative Device
To mimic python teeth, the research team conducted simulations, 3D printing, and experiments on cadavers to explore tooth shape and mechanics. Kurtaliaj developed various tooth designs, eventually creating a customized array of biomimetic teeth on a curved base made of biocompatible resin. The teeth are small to prevent them from protruding through the tendon, with the base personalized through 3D printing to match the curvature of the patient’s bone structure at the tendon attachment site.
“Our device is designed to complement current surgical approaches, enhancing the strength of the repair without requiring a complete change in procedure,” noted Kurtaliaj.
The Research Team
Kurtaliaj led the study under the guidance of Drs. Stavros Thomopoulos and Guy Genin, along with input from Dr. William Levine, Chair of the Department of Orthopedic Surgery at Columbia University. Collaborating closely with orthopedic surgeons allowed the team to incorporate valuable clinical insights into the device’s design.
Future Directions
The researchers are working on developing a bioabsorbable version of the device that degrades as the rotator cuff heals, further enhancing its clinical utility. They are also preparing for discussions with the FDA to facilitate the device’s entry into the market.
