Association Between Operative Day of the Week and Postoperative Outcomes Following Lumbar Fusion
This retrospective study of 617 lumbar fusion patients found that while Friday surgeries were associated with shorter operative times and lower 90-day emergency room admission rates, and Monday surgeries carried higher risks of readmission and emergency visits, these temporal correlations were largely influenced by surgeon-specific factors and patient social vulnerability rather than the day of the week itself.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Back in the operating room, the clock is often seen as a neutral observer, ticking away the minutes of a procedure without influencing the outcome. Yet, in the world of medicine, the day a surgery takes place can sometimes tell a story about what happens next. For decades, researchers have noticed a pattern known as the "weekend effect," where patients admitted for surgery just before or during the weekend sometimes face higher risks of complications or longer hospital stays. This phenomenon suggests that the rhythm of the hospital week—when staff are fully available, when outpatient clinics are open, and when discharge planning happens—might be just as important as the surgeon's skill. As spinal surgeries become more common, with millions of people seeking relief from back pain, understanding whether the specific day of the week matters has become a crucial question for improving patient care and reducing the burden on the healthcare system.
A team of researchers at Albert Einstein College of Medicine and Montefiore Medical Center set out to investigate this timing question specifically for lumbar fusion, a major procedure where vertebrae in the lower back are permanently joined together to stabilize the spine. They looked back at the records of 617 adults who underwent elective, or planned, lumbar fusion surgeries between 2022 and 2025. The study focused on patients who had one to three levels of their spine fused, carefully excluding emergency cases, trauma, or tumor-related surgeries to ensure they were comparing similar operations. By examining electronic medical records, the team gathered details on the patients' backgrounds, the specifics of the surgery, and what happened in the months following the operation, including whether they returned to the hospital or emergency room.
The researchers first divided the patients into two groups: those who had their surgery from Monday through Thursday, and those who had it on a Friday. At first glance, the two groups seemed quite similar in terms of age, gender, and race. However, a closer look revealed that patients operated on Friday were significantly more likely to face social challenges, such as food insecurity, housing instability, or difficulty affording basic utilities. Despite these added social hurdles, the Friday group actually had slightly lower body mass indices on average. When the team looked at the surgery itself, they found that Friday operations were shorter, taking about 249 minutes on average compared to 281 minutes for the rest of the week. These Friday surgeries also involved a higher rate of open surgical approaches, where a larger incision is made, rather than minimally invasive techniques.
Surprisingly, the data showed that patients who had surgery on Friday fared better in several key areas than those operated on earlier in the week. The Friday group was less likely to stay in the hospital for an extended period and was significantly less likely to visit the emergency room within 90 days after leaving the hospital. In contrast, patients who had their surgery on Monday were more likely to be readmitted to the hospital or return to the emergency room within three months. This finding was counterintuitive because previous studies on other types of surgery often suggested that operations later in the week carried higher risks. The researchers used advanced statistical methods to account for differences between surgeons and patient backgrounds, and even after doing so, the pattern held: Monday surgeries were still linked to higher rates of emergency visits and readmissions, while Friday surgeries remained linked to fewer emergency visits.
The study suggests that the day of the week does not change the technical success of the surgery itself, but it does influence the path of recovery. The researchers propose that the difference might be explained by when patients are discharged and what care is available to them afterward. A patient having surgery on Friday might spend the weekend in the hospital under the care of the full hospital team and be discharged early in the following week, when outpatient clinics and primary care doctors are open and ready to help. A patient having surgery on Monday, however, might be discharged right before the weekend arrives. If they develop a problem over the weekend, they may find their regular doctor's office closed and have no choice but to go to the emergency room. This timing issue, combined with the fact that many patients in this study relied on government-funded insurance, which can sometimes limit access to care, likely drives the higher readmission rates seen on Mondays.
Ultimately, the study indicates that the "weekend effect" is not a simple rule that Friday surgeries are dangerous. Instead, the results highlight how complex factors like surgeon habits, social vulnerabilities, and the timing of hospital discharge interact to shape a patient's recovery. While the specific day of the week was linked to different outcomes, the researchers found that once they accounted for who the surgeon was, many of the differences in surgery length and hospital stay disappeared. This suggests that the individual surgeon's style and schedule play a massive role in how a procedure goes. The persistent link between Monday surgeries and higher emergency room visits, however, points to a systemic issue in how patients are transitioned from the hospital back to their daily lives. The findings do not prove that one day is inherently better than another, but they do suggest that optimizing discharge timing and ensuring patients have access to care over the weekend could help reduce the need for emergency visits and improve the overall journey of recovery for those undergoing spinal fusion.
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