title: [An experimental study on the pathological changes of the intervertebral disc and its surrounding tissues after intradiscal injection of various chemical substances (the first report)].
abstract: The author has investigated the possible clinical application of new suitable and reliable substances for intradiscal therapy. MATERIALS AND METHODS; Several concentrations of various chemical substances (HCl, NaOH, etc.) were injected into the lumbar intervertebral discs of 165 Japanese white rabbits. These animals were sacrificed periodically and the obtained disc specimens were submitted to histological examinations with light and electron microscopes. Effects of these substances on the dura mater and the spinal cord of 87 guinea pigs were also investigated histologically. RESULTS; Acids, bases and ethanol, especially in high concentration, caused intense necrosis of nucleus pulposus cells and degeneration of the matrix as well as destruction of the annulus fibrosus occasionally with necrosis of endplate cells. Narrowing of disc height was frequently observed. Hemorrhage and inflammatory changes of surrounding tissues including the dura mater and the spinal cord were not rare. While low concentration acids and bases as well as other chemical substances such as osmic acid and phenol showed somewhat confined changes to the nucleus pulposus with minimal changes to peridiscal tissues including the neural structures. In other words, changes induced by these chemical substances were circumscribed to the nucleus pulposus, provided the concentration of the substances were adjusted to an appropriate level. DISCUSSIONS; Recently, chemonucleolysis and percutaneous discectomy have been recognized as alternatives to surgical treatments for lumbar disc herniation and seemed to have established a new concept "intermediate therapy". However, each method has certain disadvantages as well. The purpose of the present study is to find out safer and reliable agents that can dissolve the nucleus pulposus without adverse side effects such as anaphylaxis or transverse myelitis that occurs with some nucleolytic enzymes. In this perspective, the results of this study have provided evidences that certain chemical substances have possible clinical application in intradiscal therapy.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Chiba
mesh_terms: D000818:Animals; D017587:Diskectomy, Percutaneous / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D006851:Hydrochloric Acid / Q000009:adverse effects; D007403:Intervertebral Disc / Q000187:drug effects / Q000473:pathology*; D007404:Intervertebral Disc Chemolysis / Q000009:adverse effects*; D007405:Intervertebral Disc Displacement / Q000628:therapy; D009336:Necrosis; D011817:Rabbits; D012972:Sodium Hydroxide / Q000009:adverse effects
chemical_list: D012972:Sodium Hydroxide; D006851:Hydrochloric Acid