Thermal Generation in Spinal Surgery: Does Rate of Irrigation Matter During Anterior Cervical Discectomy?

BACKGROUND: High-speed rotational burring is considered the mainstay of modern spinal decompression surgery. However, high-energy burrs generate significant heat due to the friction between the bone and the rotating burr. This study determines the effects of automated irrigation rate on burr tip temperatures either with a serrated steel burr or diamond-coated burr during anterior cervical discectomy and fusion (ACDF). METHODS: This is an observational study of the routine practice of a single surgeon for 20 patients aged 18 years or older undergoing elective single- or multilevel ACDF. Various continuous irrigation rates of 0, 0.5, 1.0, or 2.0 cc/min were used. Forward-looking infrared thermography was used to measure the burr tip temperatures. The Midas Rex Legend EHS (Medtronic, PLC, Minneapolis, MN) stylus high-speed surgical drill was used with 3-mm burrs (diamond-coated and carbide-serrated steel) paired to the Medtronic Integrated Power Console set at 60,000 rpm. RESULTS: The 0.5-cc/min irrigation rate kept the maximum burr temperatures below 45°C (P < .001). With no irrigation (0 cc/min), the steel burrs reached a maximum of 141°C, and the diamond-coated burrs reached 177°C, which was the only significant difference related to the burr materials (P = 0.0354). With irrigation rates of 0.5 cc/min and above, the maximum recorded temperature for steel burrs was 40.6°C, and the maximum temperature for diamond-coated burrs was 38.9°C. Irrigation rates greater than 0.5 cc/min yielded little additional benefit. CONCLUSION: This study highlights the importance of adequate irrigation during high-speed burr drilling. Continuous irrigation is recommended even as low as 0.5 cc/min. It is good operative practice to reduce the risk of heat transmission to surrounding tissues, especially considering the proximity of cervical spinal nerve roots during uncoforaminal decompression. LEVEL OF EVIDENCE: 3.