Methyl methacrylate: Complications
Advanced, Clinical Subspecialties
In medicine, methylmethacrylate is used as bone cement when it is polymerized with other compounds. In orthopedics it is used in certain total hip replacements. Cementless procedures have a longer lifespan; however, they require healthier bone and patients must undergo longer recovery periods. Therefore, cemented procedures often occur in older, less healthy individuals.
Methylmethacrylate has been implicated in many perioperative complications. An important complication is Bone Cement Implantation Syndrome (BCIS). At the time of cement implantation and prosthesis insertion, the patient can experience hypoxia, hypotension, arrhythmias, increased pulmonary vascular resistance, right ventricular failure, and cardiac arrest. BCIS can also occur when the joint is reduced or the tourniquet is deflated. Very little is known about this syndrome as there is no agreed upon definition and most of the literature is in the form of case reports detailing more severe outcomes. The ultimate cause is unknown but the prevailing theory is showering of marrow, fat, cement, bone, etc. to the pulmonary vasculature results in an acute increase in PVR leading to RV dilation and failure. Risk factors for worse outcomes include ASA 3 or 4 physical status, pre-existing pulmonary hypertension, cardiac disease, osteoporosis, and pathologic fractures. There is little that can be done from an anesthetic standpoint to avoid BCIS. A discussion with surgeons about patients that may be at increased risk is warranted in order for the surgical technique to be modified. The treatment is primarily supportive. This includes FiO2 of 100%, management of RV failure with IV fluid therapy, pulmonary vasodilators, and inotropes as dictated by the clinical situation. Therapy may be directed by CO and CVP monitoring.
There are some case reports of antibiotic-loaded bone cement being attributed to postoperative acute kidney injury. These usually occurred in patients predisposed to renal failure and when aminoglycosides were the antibiotic utilized.