FDA Greenlights RevBio’s Innovative Bone Glue Trial for Cranial Surgery

The U.S. Food and Drug Administration (FDA) has given the green light for a new clinical trial to test a novel bone adhesive, a material designed to bond bones together surgically. RevBio, a Boston-based biotech business, will conduct this pilot study with its patented product, Tetranite, intended to replace the metal plates and screws usually employed in head surgeries for reconnecting skull sections after brain operations. This innovative adhesive, which promotes new bone growth, is self-setting, meaning it hardens on its own once applied, and is injectable, offering potential improvements in cranial surgery techniques. Tetranite’s breakthrough aligns with ongoing innovations in cranioplasty, where 3D printing has been increasingly used to create custom-fitted implants and models for cranial reconstruction, further enhancing the precision and effectiveness of cranial surgery.

Spearheaded by neurosurgeons Timothy Smith and Madison Michael, the trial will enroll 20 patients to verify Tetranite’s safety and effectiveness in fixing skull pieces immediately following brain surgery. This significant step follows RevBio’s successful preliminary medical evaluations and extensive laboratory research. Both Smith and Michael bring a wealth of expertise in neurosurgery to the trial. Smith is a prominent figure at Brigham and Women’s Hospital and Brigham and Women’s Faulkner Hospital in Massachusetts and serves as an Associate Professor of Neurosurgery at Harvard Medical School. Michael, a seasoned expert at Semmes-Murphey Clinic, holds the position of Professor and Program Director at the University of Tennessee. His specialized interests include skull base surgery, brain tumors, microvascular compression syndromes, and endoscopic surgery, further enhancing the depth of knowledge and experience driving this pioneering study.

Surgical breakthrough

Craniotomy, a critical surgical procedure for addressing brain tumors, aneurysms, and other intracranial issues, involves the removal of a part of the skull known as the cranial flap. Traditionally, after the surgery, this flap is reattached using metal hardware like plates and screws. However, this method has several drawbacks, including the risk of infections, particularly from cerebrospinal fluid (CSF) leaks, which can lead to serious complications like meningitis, subdural empyema, or cerebral abscesses.

According to RevBio, these complications are exacerbated by the fact that the traditional method doesn’t seal the kerf line – the gap left by the surgical instruments – adequately. This gap not only facilitates infections but also impedes the natural integration of the cranial flap with the surrounding bone. Moreover, the use of metal hardware often necessitates secondary surgeries to correct issues related to pain and hardware protrusion.

Tetranite offers a promising solution to these challenges. It is designed to fill the missing bone, seal the surgical site against infections, and support osteogenesis – the process of new bone formation. Over time, Tetranite is resorbed and replaced by natural bone, as demonstrated in RevBio’s pre-clinical testing. Its ability to provide a biological adherence between the bone flap edges and the skull while simultaneously acting as a scaffold for bone regeneration presents a significant advancement over current practices.

Clinical goals

“We are looking forward to evaluating the efficacy of the product that could provide immediate, rigid fixation that would be preferable to existing plates and screws, which are the current standard of care,” said Smith. “We’re excited at the potential that this product could provide a biological adherence between the bone flap edges and the skull, as well as an architecture for osteogenesis over time and look forward to the results of the clinical trial.”

Brian Hess, CEO and Founder of RevBio, echoes this sentiment, expressing optimism about Tetranite becoming the new standard for cranial flap fixation due to its numerous benefits over traditional methods.

RevBio’s recent achievements, including a $3.4 million National Institutes of Health (NIH) grant for the development of Tetranite for treating complex fractures, further highlight the potential of this technology. The grant will support the company’s translational research activities through the completion of the clinical trial. Previous research efforts, including a sheep study assessing the safety and efficacy of Tetranite in a wedge osteotomy fracture model in the distal femur, have shown promising results. These studies have indicated that Tetranite not only provides immediate load sharing between bone and metal hardware but also accelerates healing and reduces the likelihood of hardware failure and delayed healing.

RevBio conducted a sheep study of Tetranite using a wedge osteotomy fracture model in the distal femur. Image courtesy of Business Wire.

“Our pre-clinical studies have demonstrated that Tetranite is able to redistribute most of the load from plates and screws thereby reducing the likelihood of hardware failure and delayed healing,” said Brittany McDonough, RevBio’s R&D Program Manager, who has led the development of the fracture fixation product. “This adhesive material also provides a resorbable scaffold for the regeneration of bone which accelerates healing within the first few weeks following a traumatic injury.”

Patient benefits

3D printing has become an ideal tool in cranioplasty, particularly at leading medical institutions where it’s used for creating patient-specific implants and surgical models. For example, the Mayo Clinic has employed 3D printing to manufacture custom cranial implants, enabling a more precise fit and better aesthetic outcomes. These implants are tailored to the exact dimensions of a patient’s skull defect.

Similarly, the University of Michigan‘s medical center reported a groundbreaking case where they employed 3D printing for a complex cranial reconstruction. The patient, suffering from a significant cranial defect, received a 3D printed implant that was designed based on their CT scans. This approach not only reduced the surgical time but also significantly improved the recovery process, setting a new standard for such procedures.

These real-world applications of 3D printing in cranioplasty not only highlight the technology’s transformative impact on neurosurgery but also pave the way for integrating innovative solutions like RevBio’s Tetranite. By combining the precision and customization offered by 3D printing with the advanced properties of Tetranite, the future of surgical healthcare looks super efficient and patient-centric. This synergy between cutting-edge 3D printing techniques and new biomaterials like Tetranite could set a new standard in cranial reconstruction, offering more effective, less invasive, and faster-healing surgical options. As the medical field continues to evolve, these advancements are poised to become the norm, dramatically enhancing patient outcomes and redefining the possibilities in neurosurgery.

As the clinical trial proceeds, RevBio stands at the forefront of a significant transition in medical technology, particularly in cranial and orthopedic surgery. Like with 3D printing, the success of Tetranite in this trial could not only improve patient outcomes but also potentially reduce healthcare costs associated with post-surgical complications. The broader implications for cranial surgery and beyond are substantial, as this innovative approach could redefine standards and practices in surgical procedures, enhancing patient safety and recovery.