The substance, a polyethylene glycol (PEG) hydrogel sealant, plugs miniscule leaks in the thin sheath inside the spinal column that encloses the spinal cord, called the dura. The spinal cord and nerves float in cerebrospinal fluid inside the sheath.
The gel is an important step forward because even pinhole-sized leaks of spinal fluid can lead to another surgery and can expose the surgical wound to bacteria, increasing the risk of serious infection, including meningitis, said the study’s lead author, Kee Kim. Kim is an associate professor of neurological surgery at the School of Medicine at UC Davis, chief of spinal neurosurgery and co-director of the Spine Center.
“This substance is synthetic so there is no possibility of disease transmission but does not replace a careful surgical technique of closing the dura with the sutures,” Kim said. “This sealant allows easy repair of spinal leak that may be present even after best attempts at dural closure with suturing.”
The study, published online in the journal Spine, was conducted in 158 patients treated at 24 centers throughout the United States. It examined the effectiveness and safety of the sealant when used as an adjunct to suturing the dura during surgery.
The gel was approved for use in the spine by the Food and Drug Administration late in 2010.
For the study, patients were randomized in the operating room if a spinal fluid leak was seen after the dura was closed with the sutures. One hundred and two of the patients received the PEG hydrogel spinal sealant and 56 received standard care — closing the dura with additional sutures and/or fibrin glue. Participants were excluded from the study if they had prior spine surgery or were undergoing chemotherapy, radiation treatment or had other compounding health problems, such as compromised immune systems, uncontrolled diabetes or poor renal functioning.
The researchers determined whether the treatment had achieved a water-tight seal through the use of the “Valsalva maneuver,” essentially attempting to expel spinal fluid through the closed dura. The study found that the patients who received the sealant had a significantly higher rate of watertight closure —100 percent —versus only 64 percent watertight closure.
The PEG gel is a liquid that quickly solidifies and forms a tight seal when it comes into contact with the body. Other sealants commonly used to create a watertight seal in spinal wounds include fibrin glue, made from other donor blood or animal matter, which is not optimal because it remains in place for only five to seven days and carries a risk of disease transmission, the researchers said.
“This is one of many clinical trials carried out at the UC Davis Spine Center that helps to provide our patients with spinal disorder not only the latest but the best available treatment” Kim said.
The UC Davis School of Medicine is among the nation’s leading medical schools, recognized for its research and primary-care programs. The school offers fully accredited master’s degree programs in public health and in informatics, and its combined M.D.-Ph.D. program is training the next generation of physician-scientists to conduct high-impact research and translate discoveries into better clinical care. Along with being a recognized leader in medical research, the school is committed to serving underserved communities and advancing rural health. For more information, visit UC Davis School of Medicine at medschool.ucdavis.edu.