Carbon dioxide laser removal of polymethylmethacrylate

Polymethylmethacrylate remains an excellent method of securing orthopaedic implants. However, revision surgery may be necessary when loosening of the prosthesis has occurred with symptomatology. Removal of polymethylmethacrylate during revision surgery can be difficult. Care must be taken to avoid damage to the remaining bone and surrounding soft tissue. This study was undertaken to characterize the efficacy of the carbon dioxide (CO2) laser for cement removal in vitro and in vivo. The CO2 laser did not damage adjacent bone or soft tissue via lateral heat transfer in vitro and in vivo. The maximum bone cortex temperature during CO2 laser removal was 56 degrees C. This was lower than the 60 degrees C temperature encountered during initial cement insertion and curing. The CO2 laser preferentially penetrates polymethylmethacrylate with absorption versus apparent relative reflection with bone. The products of vaporization from CO2 laser removal of polymethylmethacrylate were removed safely (to < 12.2 ppm) with a smoke evacuator without risk to the patient or operating room personnel. Removal of polymethylmethacrylate by CO2 laser was performed in 117 patients undergoing revision operations, including 78 total hip revisions, 33 total knee revisions, 3 total elbow revisions, and 3 spine revisions. No perforation or fracture of bone occurred with the use of the laser. There was no statistical difference in surgical time, blood loss, infection rate, or hospital stay when the CO2 laser was used. There were no cases of osteonecrosis or obvious soft tissue necrosis caused by the laser. The infection rate was 3.4% (4/117) when the laser was used for cement removal.