Corrections or additions?
Spinal Disc Replacement?
This articles by Barbara Fox was published in U.S. 1 Newspaper on July 8, 1998. All rights reserved.
After the common cold, back pain is the next most frequent symptom that Americans bring to their doctors. It affects 80 percent of the population in the United States at the most productive time in their lives, typically from ages 30 to 50. Of every 1,000 people who have bad backs, 960 will get well on their own within three months. Nevertheless, 20 of those will have herniated discs accompanied by sciatica (pain that goes down the leg), and two or three of them will have surgical treatment. That's where Princeton Pike-based orthopedic surgeon Ron Wisneski hopes to be able to help.
Wisneski aims to use Biomimetics' material to implant an artificial nucleus of a spinal disc, not only using standard surgical methods, but with minimally invasive methods, even on an outpatient basis. "Once we have the data to hang our hat on," says Wisneski, "we will be welcoming back sufferers from the northeast corridor to Princeton."
Wisneski has had a longstanding research interest in the anatomy, physiology and pathology of the intervertebral disc. An alumnus of Villanova, Class of 1973, he went to Temple for medical school, did his internship at the Hospital of University of Pennsylvania (HUP), and postdoctoral work at Pennsylvania Hospital. From 1984 to 1992 he was chief of spinal surgery at HUP. A shareholder with Biomimetics, he practices at the Hospital for Special Surgery Orthopedic and Rehabilitation Center on Princeton Pike (affiliated with Cornell's medical school in Manhattan) and is on the attending staff at the Medical Center of Princeton.
"Patients need to know that there are significant new advances through the use of immunologically inert biomaterials that will not react to body zone host defense mechanisms," says Wisneski. "With proper basic science research endeavors -- conducting animal model tests under the scrutiny of the FDA -- our intent is to have an option which may substantially augment the outcome expectations of the patients who have surgery for herniated discs."
The nucleus of a spinal disc can be compared to the jelly of a jelly donut. The Biomimetics product would be used in an operation known as a "laminectomy with discectomy" that removes a portion of bone over the herniated disc to gain access to the interior of the spinal canal. The surgeon then removes the herniated material, which takes away the pressure on the nerve and removes the pain. But as Wisneski points out, "The disc is still not normal. What are you replacing it with?"
The hydrogel material made by Biomimetics (shown on the cover of this issue) will be high in water content and strong enough to perform the functions of the nucleus. "Our current research interest is to simulate the normal movable elastic shock absorbing capacity of the intervertebral disc," says Wisneski. It may also be able to transport fluids, including nutrients, though that is still being investigated.
Other applications could help the 300,000 patients annually who undergo vertebral fusion operations which can have, the surgeon says, long-term consequences as well as short-term risk. Replacing the worn-out disc will improve patients' quality of life and forgo the potential complications (which can include infection, bleeding, pain, stiffness, or paralysis) that can accompany a fusion.
"Our timeline depends on research funding," says Wisneski. "We'd like the first prototypes available for use in human subjects by the year 2000."
-- Barbara Fox
This page is published by PrincetonInfo.com -- the web site for U.S. 1 Newspaper in Princeton, New Jersey.