Full-time operating room staff in orthopaedic surgical suites are exposed to exceedingly high noise levels, say researchers, who say in one surgery, a sound level of 130 dB – similar to a jet taking off 60m away – was recorded.
The high noise levels put full-time staff at serious risk of permanent hearing loss. 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, reports MedPage Today.
Even when surgeries were not 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 eight-hour exposure.
For comparison, noise levels at construction sites average about 100 dB, while 120 dB is typical for rock concerts, said Matthew Meade, DO, of Jefferson Health, who presented the study of spinal surgeries.
“The risk of cumulative noise exposure leading to noise-induced hearing loss cannot be ignored,” he added.
Hospital shows on TV 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 orthopaedic 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 eight-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 eight-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 minimise exposure”.
Study 1 details
Risk of Noise Induced Hearing Loss in the Orthopaedic Spine Surgeon
Matthew Meade, Stephanie Ann-Gie Kwan, Mark Michael, Nicholas Minissale, Christopher Kepler, Barrett Woods, Jeffrey Gleimer.
Presented at the American Academy of Orthopaedic Surgeons annual meeting
Introduction
Orthopaedic surgeons understand the risks patients accept when undergoing surgical procedures, including bleeding, infection, and/or injury to surrounding structures. However, the risks these procedures present to surgeons themselves are often overlooked. Noise induced hearing loss (NIHL) affects one’s ability to effectively communicate and can negatively impact quality of life. The risk spine surgeons have of developing NIHL due to occupational exposures in the operating room is unknown. Sound levels are considered impermissibly high if the average decibel level (dBA) rises above 105 decibels (dB) for a period of 1 hour. The recommended exposure limit from the National Institute for Occupational Safety and Health (NIOSH) is a maximum of 85 db over an 8-hour time weighted average (TWA). The primary goal of this study is to determine whether surgical procedures commonly performed by orthopaedic spine surgeons place them at an elevated risk for NIHL.
Methods
Following Institutional Review Board (IRB) approval, a prospective review was conducted by collecting intraoperative recordings with an external microphone in the operating room (OR). Surgeries included anterior cervical discectomy and fusion (ACDF), posterior cervical decompression and fusion (PCDF), isolated lumbar laminectomies, lumbar interbody fusion (multiple approaches), posterior lumbar decompression and fusion (PLDF), posterior thoracic decompression and fusion (PTDF), microdiscectomy, and sacroiliac screws. Baseline noise levels were established using preoperative recordings to serve as a control. Surgical duration, number of levels involved in the procedure, operating surgeon, and presence of background music were collected. The highest sound pressure level was reported as “maximum dB level,” the average dB level projected over an 8-hour time period was reported as “TWA,” the percentage of allowable daily noise was reported as “dose,” and the dose projected forward over 8-hours was reported as “projected dose”.
Results
Sixty-nine recordings of inpatient spinal surgeries were collected comprised of 17 ACDFs, 2 PCDFs, 13 isolated lumbar laminectomies, 18 lumbar interbody fusions (multiple different approaches including ALIF, OLIF, and TLIF), 10 PLDFs, 3 PTDFs, 5 microdiscectomies, and 1 sacroiliac screws. Operative recordings were significantly louder than baseline for all variables including maximum dB level, TWA, dose, and projected dose (p<0.001). The maximum dB level ranged from 92.3 to 111.4 dB with an average of 102.0 dB. The highest projected dose reported was 104.1% in a microdiscectomy while the highest dose was 13.8% in a posterior thoracic decompression and fusion. The dose per case averaged 6.8% while average projected dose was 19.3% and average TWA was 68.5 dB.
Discussion and conclusion
Our study demonstrates that spine surgeons are at risk of exceeding cumulative dB limits. Decibel levels are regularly exceeding 85 dB, which is considered damaging. When performing multiple surgeries within a day, accounting for maximum dB levels greater than 90 dB in all recordings and greater than 100 dB in 63%, the aggregate effect of noise cannot be ignored. This study highlights the fact that orthopaedic spine surgeons are at elevated risk for occupational NIHL due to regular OR noise exposure.
Study 2 details
Noise-Induced Hearing Loss: Should Surgeons Be Wearing Ear Protection during Primary Hip and Knee Arthroplasty?
Vincent Wai-Ming Lau, Stephanie Ann-Gie Kwan, Rex Lutz, Paul Maxwell Courtney, Alvin C Ong, Gregory Deirmengian.
Presented at the American Academy of Orthopaedic Surgeons annual meeting
Introductions
The risk of noise-induced hearing loss (NIHL) to orthopaedic surgeons due to occupational exposures in the operating room (OR) is unknown. Noise exposure is considered hazardous at 85 decibels (dB) over an 8-hour time weighted average (TWA), with hearing protection recommended for any dB level greater than 85 dB irrespective of length of exposure. The purpose of this study is to identify whether primary arthroplasty procedures place surgeons at risk of developing NIHL.
Methods
Intraoperative recordings were taken from a microphone attached to the surgeon during manual total knee arthroplasty (TKA), manual total hip arthroplasty (THA), and robotic-assisted total knee arthroplasty (RTKA). Recordings were taken in respective operating rooms prior to surgical start time to serve as baseline controls. Decibel levels were reported as “maximum dB level,” defined as the highest sound pressure level during the measurement period, and “TWA,” defined as the average dB level projected over an 8-hour time period. Percentage of maximum allowable daily noise dose was reported as “dose,” and the measured dose projected forward over 8-hours was reported as “projected dose.”
Results
A total of 114 recordings were collected, comprising 46 baseline, 15 THA, 32 TKA, and 21 RTKA recordings. Maximum dB level ranged from 102.2 to 129.6 dB, with all procedures demonstrating significantly greater dB levels than controls (p<0.001). Maximum dB level was greater than 85 dB for all cases. RTKA had the highest dose (89.0%) and highest projected dose (1265.3%). No significant differences were found between THA and TKA for maximum dB level, TWA, dose, or projected dose, but RTKA was significantly greater than both for all variables (p<0.001). All RTKAs exceeded a projected dose of 100% with an average dose of 24.3%.
Discussion and conclusion
While manual THA and TKA procedures do not exceed recommended noise limits during a single procedure, RTKA surpass projected doses of 100%. Surgeons performing over two RTKAs per day place themselves at risk of NIHL and should consider measures such as ear protection to minimise exposure.
Study 1 article – Risk of Noise Induced Hearing Loss in the Orthopaedic Spine Surgeon (Open access)
Medpage Today article – Now Hear This: The OR Is Incredibly, Dangerously Loud (Open access)
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