['Intraparenchymal pressure (IPP) measurements in an in vitro cadaveric model of CNS edema.', 'To assess the contribution of pia mater to IPP and the effect of piotomy.', 'Multicenter randomized control trials have shown that decompression with durotomy/duroplasty significantly decreases intracranial pressure (ICP). There is a paucity of evidence regarding the effectiveness of decompression of the spinal cord by piotomy.', 'The supratentorial brain and spinal cord were removed from six fresh cadavers. Dura and arachnoid mater were removed. ICP monitors were placed bilaterally in the frontal and parietal lobes, and centrally in the cervical and thoracic spinal cord. To simulate edema, specimens were submerged in hypotonic solution. IPP was recorded for 5 days. A complete dorsal midline piotomy was performed on the spinal cord and resulting IPP was recorded.', 'Brain and spinal cord both increased in weight. IPP significantly increased in both brain and spinal cord. The IPP increase within the spinal cord was substantially greater (averages: all four lobes\u200a=\u200a4.0\u200amm Hg; cervical\u200a=\u200a73.7\u200amm Hg; thoracic\u200a=\u200a49.3\u200amm Hg). After piotomy, cervical and thoracic spinal cord IPP decreased immediately (avg. postpiotomy IPP\u200a=\u200a9.7 and 10.3, respectively).'] Does pia Mater Significantly contribute to Spinal Cord Intraparenchymal Pressure in a Simulated Model of Edema?