Neurogenic Shock Immediately following Posterior Lumbar Interbody Fusion: Report of Two Cases

Study Design Case report. Objective To present two cases of neurogenic shock that occurred immediately following posterior lumbar interbody fusion (PLIF) and that appeared to have been caused by the vasovagal reflex after dural injury and incarceration of the cauda equina. Case Report We present two cases of neurogenic shock that occurred immediately following PLIF. One patient had bradycardia, and the other developed cardiac arrest just after closing the surgical incision and opening the drainage tube. Cardiopulmonary resuscitation was performed immediately, and the patients recovered successfully, but they showed severe motor loss after awakening. The results of laboratory data, chest X-ray, electrocardiogram, computed tomography, and echocardiography ruled out pulmonary embolism, hemorrhagic shock, and cardiogenic shock. Although the reasons for the postoperative shock were obscure, reoperation was performed to explore the cause of paralysis. At reoperation, a cerebrospinal fluid collection and the incarceration of multiple cauda equina rootlets through a small dural tear were observed. The incarcerated cauda equina rootlets were reduced, and the dural defect was closed. In both cases, the reoperation was uneventful. From the intraoperative findings at reoperation, it was thought that the pathology was neurogenic shock via the vasovagal reflex. Conclusion Incarceration of multiple cauda equina rootlets following the accidental dural tear by suction drainage caused a sudden decrease of cerebrospinal fluid pressure and traction of the cauda equina, which may have led to the vasovagal reflex.