Sustained Fevers After Spinal Fusion: A Sentinel for Infection?
Postoperative fevers occur frequently. During the first 2 to 3 days after surgery, these fevers are often due to atelectasis or the increased inflammatory response that arises from tissue injury during surgery. However, persistent postoperative fevers should be cause for concern. In the August 19, 2020 issue of The Journal, Hwang et al. examine the relationship between sustained fevers after spine instrumentation and postoperative surgical site infection.
The authors retrospectively reviewed 598 consecutive patients who underwent lumbar or thoracic spinal instrumentation. They excluded patients who underwent surgery to treat tumors or infections and those with other identified causes of fever, such as a urinary tract infection or pneumonia. Sustained fevers were defined as those that began on or after postoperative day (POD) 4 and those that started on POD 1 to 3 if they persisted until or beyond POD 5.
Sixty-eight patients (11.4%) met the criteria for a sustained fever after spinal instrumentation. Nine of those 68 (13.2%) were diagnosed with a surgical site infection. Of the 530 patients who did not have a sustained fever, only 5 (0.9%) developed a surgical site infection (p<0.001 for the between-group difference).
Further analysis revealed 3 diagnostic clues for surgical site infections among the patients with sustained fevers:
- Continuous fever (rather than cyclic or intermittent)
- Levels of C-reactive protein (CRP) >4 mg/dL after POD 7
- Increasing or stationary patterns of CRP level and neutrophil differential
In addition, the authors found that CRP levels >4 mg/dL between PODs 7 and 10 had much greater sensitivity for discriminating surgical site infection than gadolinium-enhanced magnetic resonance imaging data obtained within 1 month of the surgical procedure.
Although a vast majority (87%) of patients with sustained postoperative fevers in this study did not develop an infection, persistent fever after spine instrumentation surgery is something to be mindful of. The authors describe their findings as “tentative” and advise readers to interpret them with caution. Those caveats notwithstanding, I consider this information to be valuable because it might help prevent delays in the diagnosis of a potentially serious perioperative complication.
Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media
What’s New in Musculoskeletal Infection 2020
Every month, JBJS publishes a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Click here for a collection of all OrthoBuzz specialty-update summaries.
This month, Thomas K. Fehring, MD, co-author of the July 15, 2020 “What’s New in Musculoskeletal Infection,” selected the five most clinically compelling findings—all focused on periprosthetic joint infection (PJI)—from among the more than 80 noteworthy studies summarized in the article.
PJI Prevention
–A retrospective case-control study1 found that patients who received an allogeneic blood transfusion during or after knee or hip replacement had a higher risk of PJI than those who were not transfused.
PJI Diagnosis
–A retrospective review2 found that using inflammatory markers to diagnose PJI in immunosuppressed joint-replacement patients is not suitable and that newly described thresholds for synovial cell count and differential have better operative characteristics.
Treating PJI
–A retrospective review3 of a 2-stage debridement protocol with component retention in 83 joint-replacement patients showed an 86.7% success rate of infection control at an average follow-up of 41 months.
–A single-center study4 of perioperative antibiotic selection for patients undergoing total joint arthroplasty found that the risk of PJI was 32% lower among those who received cefazolin compared with those who received other antimicrobial agents. The findings emphasize the importance of preoperative allergy testing in patients with stated beta-lactam allergies.
–A review of regional and state antibiograms5 showed that 75% of methicillin-sensitive S. aureus (MSSA) isolates and 60% of both methicillin-resistant S. aureus (MRSA) and coagulase-negative Staphylococcus isolates were susceptible to clindamycin, whereas 99% of all isolates were susceptible to vancomycin.
References
- Taneja A, El-Bakoury A, Khong H, Railton P, Sharma R, Johnston KD, Puloski S, Smith C, Powell J. Association between allogeneic blood transfusion and wound infection after total hip or knee arthroplasty: a retrospective case-control study. J Bone Jt Infect. 2019 Apr 20;4(2):99-105.
- Lazarides AL, Vovos TJ, Reddy GB, Kildow BJ, Wellman SS, Jiranek WA, Seyler TM. Traditional laboratory markers hold low diagnostic utility for immunosuppressed patients with periprosthetic joint infections. J Arthroplasty.2019 Jul;34(7):1441-5. Epub 2019 Mar 12.
- Chung AS, Niesen MC, Graber TJ, Schwartz AJ, Beauchamp CP, Clarke HD, Spangehl MJ. Two-stage debridement with prosthesis retention for acute periprosthetic joint infections. J Arthroplasty.2019 Jun;34(6):1207-13. Epub 2019 Feb 16.
- Wyles CC, Hevesi M, Osmon DR, Park MA, Habermann EB, Lewallen DG, Berry DJ, Sierra RJ. 2019 John Charnley Award: Increased risk of prosthetic joint infection following primary total knee and hip arthroplasty with the use of alternative antibiotics to cefazolin: the value of allergy testing for antibiotic prophylaxis. Bone Joint J.2019 Jun;101-B(6_Supple_B):9-15.
- Nodzo SR, Boyle KK, Frisch NB. Nationwide organism susceptibility patterns to common preoperative prophylactic antibiotics: what are we covering? J Arthroplasty.2019 Jul;34(7S):S302-6. Epub 2019 Jan 17.
Revision Shoulder Arthroplasty: IV or Oral Antibiotics?
Surgeons performing revision shoulder arthroplasty typically order postoperative antibiotics to be administered while they wait for results from intraoperative cultures. Based on their index of suspicion from preoperative exams and intraoperative observations, they order either intravenous (high suspicion of infection) or oral (low suspicion) antibiotics during the waiting period. In the June 3, 2020 issue of JBJS, Yao et al. report on a retrospective review of 175 patients who underwent revision shoulder arthroplasty, finding that surgeons’ presumptive choice of antibiotic type matched the culture results in 75% of the cases.
Among the 175 patients in the study, IV antibiotics were initiated in 62, while 113 patients received oral antibiotics. Cultures from 49 of the 62 patients started on IV antibiotics came back positive, and cultures from 83 of the 113 patients started on oral antibiotics came back negative. Treatment of patients whose initial antibiotic regimen did not match culture results was modified accordingly.
After multivariate analysis Yao et al. found that male sex, prior ipsilateral infection, and intraoperative presence of a humeral membrane were 3 independent predictors of surgeons initiating IV antibiotics. Antibiotic-related adverse events (including GI, dermatologic, and allergic reactions) occurred in 19% of the patients. Not surprisingly, the rate of these complications was highest among those receiving IV antibiotics.
Although the surgeons’ empirical initiation of antibiotic administration route was “correct” 75% of the time, that still left 25% of the patients needing modification of therapy based on culture results. While the authors observe that their study was not designed “to report the relative effectiveness of the 2 antibiotic protocols in minimizing the risk of recurrent infection,” their findings confirm that preoperative and intraoperative observations can help surgeons select the “right” type of antibiotic without culture results—and that is heartening.
How to Safely Restart Elective Surgery Amid a Pandemic
OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Chad A. Krueger, MD, co-author of a recent fast-tracked review article in JBJS.
I’ll admit that when I first started hearing about COVID-19, I didn’t pay much attention. Life was busy, and I wasn’t going to worry about something that I figured would come and go without much fuss over the next few months. While that was obviously a faulty assumption, I think few of us could have predicted just how deadly, anxiety-provoking, and disruptive this virus would be. We are now 5 or so months into this pandemic and nothing is ”normal,” but some of the measures we have taken to help flatten the curve seem to be working. In the months ahead, figuring out how to safely regain some normalcy in our lives will require careful planning, nimble adjustments, and well-coordinated cross-functional execution.
Those three actions were also required to produce the fast-tracked Current Concepts Review article in JBJS about resuming elective orthopaedic surgery during the pandemic, which I had the privilege to co-author. Amazingly, that article progressed from an idea to a published manuscript, with input from 77 physicians, in the span of 2 weeks. This fast-paced project was driven by our knowledge that many facilities worldwide were getting ready to start performing elective surgeries again, and we wanted to ensure that practical, accurate, and relevant information was available as those plans were being made.
All the expert author-contributors offered unique insights as to how the pandemic was affecting healthcare delivery in their region of the globe, allowing us to keep the recommendations as balanced as possible. Although much of the research incorporated in this review came from outside the orthopaedic literature, it all touched on our ability to safely care for patients. The process of creating this article was a great example of how strong leadership, teamwork, and compromise can help us navigate through all aspects of these uncharted waters. Everyone who worked on this manuscript, including the peer-review and editorial teams at JBJS, had one goal in mind: to help orthopaedic surgeons safely return to caring for their patients.
The international consensus group that created this review is well aware that some of the recommendations will need to be updated, changed, or maybe even scrapped altogether as we learn more about the behavior of this virus. We drafted, discussed, and revised these guidelines while appreciating that some regions of the world have not been as adversely affected as others and that there are stark global differences in testing capabilities and supplies of personal protective equipment and other resources. We are painfully aware that some of our strongest recommendations might be impossible to implement in certain settings.
Developing a one-size-fits-all framework for restarting elective orthopaedic surgery was not possible; there are simply too many variables at play with this pandemic that are beyond any individual’s or health system’s control. However, this review provides as much evidence-based guidance as possible so that individual surgeons, practices, hospitals, and municipalities can make informed decisions about how elective surgery should reemerge. We are fully aware that some people may object to some of the recommendations in this article, even though 94% to 100% of the 77-member consensus group agreed on all of them. Nevertheless, we hope that this guidance—and updates to it as more evidence becomes available—will help us all continue to make highly informed decisions before, during, and after elective surgery to keep ourselves and our patients safe.
Chad A. Krueger, MD is an orthopaedic fellow in adult reconstructive surgery at the Rothman Institute and former Deputy Editor for Social Media at JBJS.
Number of COVID-19 Infections: Vastly Underestimated?
Many scientists worldwide are engaged in predicting the course of the COVID-19 pandemic, but the exact nature of this disease and the “novel” virus that causes it remains largely mysterious.
The numbers of confirmed cases in media reports are dependent on the extent of testing, which has varied markedly from region to region in North America. The scientific community has cautioned policymakers not to rely entirely on “observable” data (i.e., testing-confirmed COVID-19 cases) because such measures are likely to under-report the extent of the problem. That’s one reason why orthopaedic surgeon Mohit Bhandari, MD and his colleagues applied machine-learning tools to estimate the number of “unobserved” COVID-19 infections in North America.
The authors’ stated goal was to contribute to the ongoing debate on detection bias (one form of which can occur when outcomes—infections in this case—cannot be reliably counted) and to present statistical tools that could help improve the robustness of COVID-19 data. Their findings suggest that “we might be grossly underestimating COVID-19 infections in North America.”
The authors’ estimates relied on 2 sophisticated analyses: “dimensionality reduction” helped uncover hidden patterns, and a “hierarchical Bayesian estimator approach” inferred past infections from current fatalities. The dimensionality-reduction analysis presumed a 13-day lag time from infection to death, and it indicated that, as of April 22, 2020, the US probably had at least 1.3 million undetected infections, and the number of undetected infections in Canada could have ranged from 60,000 to 80,000. The Bayesian estimator approach yielded similar estimates: The US had up to 1.6 million undetected infections, and Canada had at least 60,000 to 86,000 undetected infections.
In contrast, data from the Johns Hopkins University Center for Systems Science and Engineering on April 22, 2020, reported only 840,476 and 41,650 confirmed cases for the US and Canada, respectively. Based on these numbers, as of April 22, 2020, the US may have had 1.5 to 2.02 times the number of reported infections, and Canada may have had 1.44 to 2.06 times the number of reported infections.
The authors emphasize that the “real” number of asymptomatic carriers cannot be determined without widespread use of validated antibody tests, which are scarce. Bhandari et al. conclude that policymakers should “be aware of the extent to which unobservable data—infections that have still not been captured by the system—can damage efforts to ‘flatten’ the pandemic’s curve.”
Avoid the Slipstream When Walking, Running, and Cycling
Many people have taken to walking, running, and cycling for the benefit of mind and body during the COVID-19 pandemic, and many engage in those activities with others. New, unpublished research coming out of the Netherlands and Belgium suggests that 2 or more people walking, running, or cycling right behind one another should leave much more than 6 ft of space between themselves.
Using animations developed from computational fluid dynamics models, the researchers showed that a cloud of emitted respiratory droplets is entrained in the slipstream–the wake behind any moving person that pushes air slightly behind them–even when he or she exhales normally. People cycling in groups often use the slipstream of the person in front of them to reduce air resistance, but smaller slipstreams also form behind anyone who is walking or running.
Admitting that much more needs to be learned about the coronavirus-infection risk posed by such slipstream-carried droplets, the authors show that when someone walks through the droplet cloud left by the person in front of them, droplets can stick to the following person’s body.
So how far back should you be from the person in front of you when you are out doing these things? The authors recommend the following distances:
- 13 to 16 ft (4 to 5 meters) while walking
- 33 ft (10 meters) when running or cycling slowly
- 65 ft (20 meters) when cycling fast
These preliminary findings suggest that exercising side by side may be safer than exercising one behind another, but doing so is often not practical or safe, especially when cycling on public roads.
Although these data are unpublished, in their white paper the authors said, “We decided it would be unethical to keep the results confidential and keep the public waiting months for the peer review process to be completed.”
OrthoBuzz would like to thank Dr. Freddie Fu, Chair of Orthopaedic Surgery at the University of Pittsburg Medical Center, for bringing this research to our attention.
Amid COVID-19, What Does “Elective” Mean?
As Sarac et al. note in the latest JBJS fast-tracked article, the phrase “elective procedure” is ambiguous, even though it is supposed to identify procedures that are being postponed to help hospitals cope with the COVID-19 pandemic. Guidelines from the Centers for Disease Control and Prevention (CDC) say that operations for “most cancers” and “highly symptomatic patients” should continue, but that leaves much of the ambiguity unresolved. What constitutes an elective procedure in orthopaedics at this unusual time remains unclear.
To help clarify the situation, the authors summarize guidance issued by states and describe the guidelines currently in use for orthopaedic surgery at their institution, The Ohio State University College of Medicine.
Here are the state-related data collected by Sarac et al., as of March 24, 2020:
- 30 states have published guidance regarding discontinuation of elective procedures; 16 of those states provide a definition of “elective” or offer guidance for determining which procedures should continue to be performed.
- 5 states provide guidelines specifically mentioning orthopaedic surgery; of those, 4 states explicitly permit trauma-related procedures, and 4 states recommend against performing arthroplasty.
- 10 states provide guidelines permitting the continuation of oncological procedures.
In the Buckeye State, the Ohio Hospital Association asked each hospital and surgery center to cancel procedures that do not meet any of the following criteria:
- Threat to a patient’s life if procedure is not performed
- Threat of permanent dysfunction of an extremity or organ system
- Risk of cancer metastasis or progression of staging
- Risk of rapid worsening to severe symptoms
Mindful of those criteria, individual surgical and procedural division directors at the authors’ university developed a list of specific procedures that should continue to be performed. Respective department chairs approved the lists, which were then sent to the hospital chief clinical officer for signoff.
The authors tabulate the orthopaedic procedures that continue to be performed at their institution as of March 25, 2020, but they are quick to add that even this list is not without ambiguity. For example, surgery should continue on “select closed fractures that if left untreated for >30 days may lead to loss of function or permanent disability,” but that requires surgeons to judge, in these uncertain and fluid times, which fractures necessitate fixation in the short term.
Sarac et al. emphasize that such lists, however specific they are today, are likely to change as demands on hospitals shift. They suggest that as the pandemic evolves, a further classification of procedures into 2 time-based categories might be helpful: (1) those that need to be performed within 2 weeks and (2) those that need to be performed within 4 weeks. Sarac et al. also remind orthopaedic surgeons to provide patients waiting for surgery that has been postponed with information regarding safe and effective methods of managing their pain.
Learnings from Orthopaedists Infected with COVID-19
One serious challenge in responding to COVID-19 is how to better protect healthcare workers and prevent nosocomial infection. A fast-track JBJS Orthopaedic Forum article by Guo et al. provides instructive data about this challenge from 24 orthopaedic surgeons in Wuhan, China who contracted the illness. Orthopaedic surgeons generally don’t work on the front lines of infectious-disease pandemics, but these cases help us understand the overall infection situation of healthcare workers.
Twenty-six orthopaedic surgeons from 8 of 24 investigated hospitals in Wuhan were identified as having COVID-19, and 24 of them completed a self-administered questionnaire. From that information, the authors found that the peak date of onset of orthopaedic surgeons’ infection was 8 days earlier than the peak of the public epidemic, indicating that these surgeons were probably exposed to COVID-19 in the hospitals, rather than in the community. Fifteen surgeons were admitted to the hospital for treatment, and 9 surgeons self-isolated at home or hotels with medicine for at least 2 weeks. All 24 surgeons recovered after treatment.
According to questionnaire responses, the suspected in-hospital sites of exposure were general wards (79.2%), public places in the hospital (20.8%), operating rooms (12.5%), the intensive care unit (4.2%), and the outpatient clinic (4.2%). Three surgeons were exposed during operations on patients who were diagnosed as having COVID-19 several days after the surgical procedures.
This and other findings underscore an already-known but worrisome feature of this disease: many asymptomatic patients with COVID-19 are shedding the virus and unwittingly exposing other people—inside and outside of hospitals—to the risk of infection.
Also worrisome: these 24 orthopaedists infected others in 25% of cases, with a 20.8% transmission rate to family members. The authors therefore recommend that orthopaedic surgeons who work in hospital settings during the COVID-19 pandemic period avoid close contact with family members at home.
Risk Factors for Infection
The authors also conducted a 1:2 matched case-control study to explore possible risk factors for COVID-19 infection. The controls were selected from uninfected orthopaedic surgeons who worked in the same department as the case(s) at each hospital.
Severe fatigue of orthopaedic surgeons during the 2 months before the outbreak was found to be a risk factor for COVID-19 infection. (Fatigue from overwork, less sleep, and mental stress are issues for orthopaedic surgeons under many “normal” circumstances.)
Real-time training in infection-prevention measures was found to have a protective effect against COVID-19, as was wearing respirators or masks all the time. More specifically, not wearing an N95 respirator was found to be a risk factor.
Generally, Guo et al. conclude that orthopaedic surgeons must be highly vigilant to avoid infection with COVID-19. They recommend the following approaches:
- Work with medical and orthopaedic associations to provide real-time infection-control training and to address any shortages of personal protective equipment.
- Minimize, postpone, or cancel elective operations. Test patients for COVID-19 before any operation if resources allow. Place face masks on all patients.
- Wear N95 respirators all the time while in a hospital during the pandemic.
- If you are exposed to the virus by patients with confirmed or suspected COVID-19, avoid close contact with family members at home and maintain physical distance in other situations.
- If possible, avoid long-term overwork and fatigue, which could compromise immunity against COVID-19.
Managing Fractures in Patients with COVID-19
As JBJS Editor-in-Chief Marc Swiontkowski, MD observed in a recent editorial, some musculoskeletal health professionals “have been set aside to some degree” during the COVID-19 pandemic. However, Dr. Swiontkowski also emphasized that “emergency/urgent procedures [still] need to be carried out.” Which leads to the question: What are the best medical practices for patients who have both fracture and COVID-19 infection.
To help answer that question, JBJS fast-tracked the publication of an article by Mi et al., which retrospectively reviewed the medical records of 10 patients from 8 hospitals in China who had both a bone fracture and COVID-19 infection.
Presenting Symptoms
All of the fractures were caused by accidents, most of them low-velocity. Flu-like symptoms of patients with a fracture and COVID-19 disease were diverse, as follows:
- 7 patients (70%) reported fever, cough, and fatigue.
- 4 (40%) had a sore throat.
- 5 (50%) presented with dyspnea.
- 3 (30%) reported dizziness.
- 1 patient (10%) reported chest pain, nasal congestion, and headache.
- 1 patient (10%) reported abdominal pain and vomiting.
Imaging and Lab Results
Six of the 10 patients were positive for SARSCoV-2 based on quantitative reverse transcription polymerase chain reaction (qRT-PCR) of throat-swab samples. All patients ultimately showed evidence of viral pneumonia on computed tomography (CT) scans, but on admission 3 patients did not exhibit severe symptoms or have obvious evidence of COVID-19 on CT scans, and they therefore underwent a surgical procedure. Fever and fatigue signs were observed in these 3 patients after the operation.
The overall results of laboratory tests were as follows:
- 6 patients had lymphopenia (<1.0 x 109 cells/L)
- 9 patients had a high level of C-reactive protein.
- 9 patients had D-dimer levels that exceeded upper normal limits. The authors suggest that this finding “could represent the special laboratory characteristics of fractures in patients with COVID-19.”
Management
Three of the 10 patients underwent surgery; the others were managed nonoperatively due to their compromised status.
All patients received antiviral therapy and antibacterial therapy, and 9 patients were managed with supplemental oxygen. None of the patients received invasive mechanical ventilation or extracorporeal membrane oxygenation because of local limitations in medical technology.
Outcomes
Four patients died in the hospital. Among those who died, surgery had been performed on 1. The clinical outcomes for the 6 surviving patients have not yet been determined.
Conclusions
Because 7 of the 10 patients were determined to have developed a nosocomial infection, the authors emphasize the need “to adopt strict infection-control measures…Doctors, nurses, patients, and families should be wearing protective devices such as an N95 respirator and goggles.”
Mi et al. propose the following 3 additional strategies for patients with a fracture and COVID-19 pneumonia:
- Consider nonoperative treatment for older patients with fractures, such as distal radial fractures, in endemic areas.
- Give patients with a fracture and COVID-19 pneumonia more intensive surveillance and treatment.
- Perform surgery on patients with a fracture and COVID-19 pneumonia in a negative-pressure operating room.
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