Image: The Neuro-Spinal scaffold (Photo courtesy of InVivo Therapeutics).
A novel bioresorbable polymer scaffold placed within a spinal cord injury (SCI) site provides structural support to the spared spinal tissue, and a supportive matrix to facilitate endogenous repair processes.
The InVivo Therapeutics (Cambridge, MA, USA) Neuro-Spinal scaffold is a highly porous device designed to mitigate tissue damage resulting from some of the critical patho-physiological events that occur during the acute phase of SCI, including increase in tissue pressure, hemorrhage, and edema. The scaffold is composed of two biocompatible, bioresorbable polymers, Polylactic-co-glycolic acid (PLGA) and Poly-L-Lysine (PLL), a positively charged polymer conducive to cellular attachment and neurite outgrowth.
The scaffold is trimmed and fitted in the epicenter of the SCI, where it modulates the healing process by providing biocompatible and cellular-adhesive appositional healing, similar to the function of sutures or a butterfly bandage in a skin laceration. It then degrades over several weeks. A study that examined the objective performance of the scaffold in 19 SCI patients showed conversion from complete paraplegia to incomplete injury within six months in 44% of the patients, exceeding the 25% conversion criterion. The study was presented at the American Association of Neurological Surgeons (AANS) annual meeting, held during May 2018 in New Orleans (LA, USA).
“At the time of stabilization surgery, a decompression laminectomy was done at the site of injury and the maximal damage was determined by ultrasonography,” said study presenter Stuart Lee, MD, of Vidant Health (Greenville, NC, USA). “Surgeons exposed the contusion through durotomy/myelotomy, used gentle irrigation to remove the necrotic tissue, and exposed the intramedullary cavity. As a side note, this gave us an opportunity to look at the pathology of acute SCI in humans, something that is generally only possible at autopsy.”
Large, multinational natural history databases consistently indicate that only 12-16% of subjects with complete thoracic injury will convert to an improved American Spinal Injury Association Impairment Scale (AIS) grade by six months after injury.