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LAS VEGAS -- Noise levels in orthopedic surgical suites often match those of a rollicking nightclub, putting full-time operating room personnel at risk for permanent hearing loss, researchers reported here.

In two studies from a group based at Jefferson Health in Philadelphia, presented at the American Academy of Orthopaedic Surgeons annual meeting, maximum noise levels approached 120 dB during total joint replacement procedures and topped 100 dB in spinal surgeries.

Even when surgeries weren't being performed, noise levels recorded in operating rooms routinely hit 85 dB, which the National Institute of Occupational Health and Safety (NIOSH) has set as the maximum tolerable for 8-hour exposure.

For comparison, noise levels at construction sites average about 100 dB, while 120 dB is typical for rock concerts, according to Matthew Meade, DO, of Jefferson Health, who presented the study of spinal surgeries.

In one surgery, a sound level of 130 dB -- similar to a jet taking off 200 feet away -- was recorded. "The risk of cumulative noise exposure leading to noise-induced hearing loss cannot be ignored," he said.

Hospital shows on television often portray operating rooms as funereally quiet, with instruments clinking softly and staff talking in subdued tones. The reality, of course, is quite different, particularly in orthopedic suites where steel mallets and power saws and drills are tools of the trade.

To examine the degree to which such noises might be excessive, the Jefferson group outfitted surgeons with decibel meters affixed to their chest pockets. Recordings were made continuously while the surgeons were in the operating room, both during actual procedures as well as before and after. The study of joint arthroplasties (with Stephanie Kwan, DO, of Jefferson as lead author) covered 68 procedures; for spinal procedures, 102 were recorded. Both studies also included the same 46 recordings from non-operative periods that served as baseline for comparisons.

In his study of spinal surgeries, Meade reported that 76% of procedures featured noises exceeding 100 dB. In addition to setting 85 dB as the maximum 8-hour average, NIOSH has also indicated that sound levels greater than 100 dB should not exceed 15 minutes in a day. Surgeons and other personnel doing spinal surgeries may therefore be at significant risk, he suggested.

The arthroplasty study found that conventional procedures (n=47) had the highest maximum sound levels, but robot-assisted knee procedures (n=21) had higher averages. Peak sound levels averaged 123 and 122 dB, respectively, for conventional procedures, compared with a mean of 107 dB with robot assistance. Averages were 78 dB with robots and about 70 dB in conventional surgeries.

For robot-assisted knee procedures, each one accounted for about 22% of the daily "safe" noise load, the group calculated. That may seem safe, but when projected over an 8-hour day the cumulative exposure was triple the level considered safe.

Kwan's group suggested that surgeons performing more than two robot-assisted knee procedures a day are "at risk" for hearing loss and "should consider measures such as ear protection to minimize exposure."