The Barricaid® Explained
The Barricaid® was designed and developed to address the type of defects in the disc anulus that are most at risk of resulting in failure following lumbar discectomy. Literature indicates that any larger defect is as much as 25 times more likely to reherniate following discectomy than smaller, slit-type defects. The Barricaid® treats larger defects by creating a barrier for the remaining nucleus to hold it within the disc in the damaged anulus.
There are many challenges in replacing a section of damaged anulus. Pressures within the disc are some of the highest ever measured in the human body, with peaks having been measured as high as 23 atmospheres**Wilke et al., New in vivo measurements of pressures in the intervertebral disc in daily life. Spine 1999 Apr 15;24(8):755-62, or 10 times the pressure in a car tire. The remaining anulus may also be damaged and has been shown to have a very poor potential for healing following injury due to the lack of a direct blood supply. The discs in the lower back are also quite mobile, importantly allowing significant motion as we bend and move, with the anulus around the outer edge of the disc moving the most. Poor healing coupled with very high pressure and bending means that any solution to closing large defects must be both secure and durable to provide the necessary stability and resistance against recurrent herniation after discectomy.
The design and placement of the Barricaid® were carefully chosen to meet these challenges. The Barricaid® is formed from a flexible mesh comprising multiple layers of counter-angulated fibers made from a non-degrading polymer with a long history of use in the body. The layers mimic the structure of healthy anulus, which is itself formed from multiple layers of counter angled fibers of collagen, one of the body’s basic building blocks. Each layer of the Barricaid® mesh is shaped to optimize flexibility while maximizing strength of the overall structure. The layers are sewn together and firmly secured to a strong titanium bone anchor that anchors the mesh to one of the surrounding vertebral bones. Titanium is an optimal material for anchoring to bone and the surface of the anchor is textured to improve the bone’s ability to grow onto the anchor, creating lasting fixation. The anchor provides a firm foundation for the mesh so that it remains in place under the extreme pressures and motion of the disc. The security of the anchor has the added advantage of not requiring any special restrictions of activity following surgery beyond those normally prescribed for discectomy alone.
During the surgery Barricaid® mesh is placed on the inner surface of the disc anulus. This location provides a very important advantage – it positions the mesh to use the disc pressure to help seal the defect against leakage of nucleus.
A final key to the success of the Barricaid® is the simplicity and repeatability of the surgical technique. An implantable device can only be as good as its final placement and appropriateness for the patient being treated. Intrinsic has endeavored to create a simple technique requiring only 5-10 minutes to implant the Barricaid® at the end of a limited discectomy. The implant comes in multiple sizes to treat most anular defect widths and is preloaded on a single-use delivery system. Implantation requires only a few simple steps to select, target and tap in the appropriately sized implant.
Intrinsic Therapeutics is dedicated to patient safety and science driven improvements in spine care. As a result, the pre-clinical and ongoing clinical testing of the Barricaid® has been thorough and rigorous. During development, the implant and delivery system had to pass testing that represents the true worst-case scenarios involving the highest loads and most degenerative conditions anticipated. These cadaveric, animal, and bench tests were run both within the company and at multiple leading university labs in the U.S. and Germany with renowned experts in spinal anatomy, physiology and biomechanics. Both the safety and performance were thoroughly investigated in these tests prior to the first patient implant. This confirmed the Barricaid®’s ability to resist reherniation in worst case anular defects without device failure following millions of cycles at the highest loads ever measured in the human disc. Since that time, the company has conducted two, implant-only safety studies involving 75 patients. These clinical investigations started in May of 2008 and based on the success of these studies, the company initiated a world-class, randomized prospective clinical study currently underway to confirm both the clinical and economic effectiveness of the Barricaid®.
The Barricaid® represents the culmination of more than 10 years of scientific and clinical investigation into the anatomy, pathology, and biomechanics of the herniated disc by many of the top scientists and surgeons in the field of spine surgery. The resulting implant, its design, final placement within the disc, and implantation system were optimized on the basis of this investigation to maximize the positive and lasting clinical impact of replacing a larger section of a damaged anulus in the subset of patients that stand to benefit most.