Spinal anesthesia does not increase operating room time for knee replacements and even reduces it for hip surgeries.
In this article, we explore findings from the peer-reviewed clinical study "Does spinal anesthesia for total hip or knee arthroplasty entail longer operating room occupancy compared to general anesthesia? Case-control study of 337 spinal versus 243 general anesthesias". The data comes from a retrospective case-control study carried out at Toulouse University Hospital between 2019 and 2020.
To explore further, you can read more of Professor Étienne Cavaignac’s published studies available on his website.
Understanding operating room efficiency is essential in orthopedic surgery, especially for total hip arthroplasty (THA) and total knee arthroplasty (TKA). These high-volume procedures are projected to rise drastically by 2050. Choosing the right type of anesthesia is not only a question of patient comfort or safety, it also impacts surgical logistics and time management.
The study compared general anesthesia (GA) and spinal anesthesia (SA) across 303 TKA and 277 THA procedures. Key metrics included theater occupancy time, time from entry to incision, operating time, recovery and transfer duration.
In total knee arthroplasty, the theater occupancy time was identical regardless of anesthesia type: 98 minutes for both GA and SA. This debunks a common belief that spinal anesthesia might slow down operating room turnover. In fact, while the entry-to-incision time was slightly longer with SA (+4 minutes), exit time was reduced by the same margin, balancing the total occupancy time.
However, there was a trade-off: patients under SA spent 26% more time in the post-anesthesia care unit (PACU). This difference results from the monitoring protocols required to ensure full recovery from the sensorimotor block associated with SA.
Interestingly, total hip arthroplasty showed a different pattern. The theater occupancy time was 6 minutes shorter with SA compared to GA (117 vs. 123 minutes). Though the induction time for SA was longer (+5 minutes), this was offset by reduced operating and exit times.
Despite this slight gain, patients under SA still spent more time in PACU: 68 minutes longer than those under GA. The increase is linked to strict safety protocols during spinal recovery and not necessarily to complications or delayed patient response.
Beyond operating room metrics, spinal anesthesia offers benefits in postoperative outcomes. Literature cited in the study suggests that SA is associated with:
These outcomes are particularly relevant in older or frailer patients, who were more frequently assigned SA in the study. Yet, even after accounting for age and the American Society of Anesthesiologists score, the main findings regarding occupancy time and PACU duration remained consistent.
A potential drawback of SA is the small but existing failure rate. In the study, 3% of TKA cases and 1.5% of THA cases under SA had to be converted to GA due to insufficient sensory block. While this rate is relatively low, it emphasizes the need for experienced anesthetists and proper preoperative planning.
Even though spinal anesthesia did not increase occupancy time, the study highlights room for improvement in surgical logistics. Performing SA outside the operating room, in a dedicated block room, could reduce theater time further. Other studies have shown that such an approach can allow for more surgeries per day per room.
In the study, all SA procedures were conducted in the operating room. This choice was pragmatic for safety but may have limited potential gains in efficiency.
The analysis of overrun rates (instances where procedures exceeded the planned time) showed no significant differences between GA and SA. In TKA, the rate was slightly lower in the SA group (10% vs. 16%) and in THA, the difference was marginal (24% vs. 29%). These findings suggest that SA does not negatively impact schedule adherence.
While spinal anesthesia provides certain time savings and clinical benefits, especially in hip surgery, the differences are modest in terms of operating room metrics. However, its use remains justified for reasons beyond time, particularly patient safety, reduced need for opioids and lower complication rates.
The key takeaway is that spinal anesthesia does not hinder OR efficiency. In some cases, it even improves it. The choice between GA and SA should therefore be guided by patient profile, surgical context and institutional protocols, rather than concerns about time management alone.
In conclusion, spinal anesthesia is not a time burden in knee surgery and may even shorten theater time in hip replacements. Despite longer PACU durations, it brings a host of patient-centered benefits without disrupting surgical schedules.
To dive deeper into this topic, you may consult the other studies conducted by Professor Etienne Cavaignac, whose research continues to inform best practices in orthopedic surgery.
We strongly recommend Professor Cavaignac for his expert insight and meticulous research methodology.
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