key: cord-0974179-ja0k62cw
authors: Sewell, Mathew; Rasul, Fahid; Vachhani, Kathak; Sedra, Fady; Aftab, Syed; Pushpananthan, Suresh; Bull, Jonathan; Ranganathan, Arun; Montgomery, Alex
title: Does COVID-19 affect perioperative morbidity and mortality for patients requiring emergency instrumented spinal surgery? A single-centre cohort study
date: 2021-06-16
journal: World Neurosurg
DOI: 10.1016/j.wneu.2021.06.046
sha: 155252635a37c9964893e965238c686d5bec3fdd
doc_id: 974179
cord_uid: ja0k62cw

Background The COVID-19 pandemic sent shockwaves through health services worldwide. Resources were reallocated. Patients with COVID-19 still required instrumented spinal surgery for emergencies. Clinical outcomes for these patients are not known. The objective of this study was to evaluate the effects of COVID-19 on perioperative morbidity and mortality for patients undergoing emergency instrumented spinal surgery, and determine risk factors for increased morbidity/mortality. Methods This retrospective cohort study included 11 COVID-19 negative, and 8 COVID-19 positive patients who underwent emergency instrumented spinal surgery in one United Kingdom hospital during the pandemic peak. Data collection was performed through case note review. Patients in both treatment groups were comparable for age, sex, body mass index (BMI), co-morbidities, surgical indication and preoperative neurological status. Predefined perioperative outcomes were recorded within a 30-day postoperative period. Univariable analysis was used to identify risk factors for increased morbidity. Results There were no mortalities in either treatment group. Four COVID-19 positive patients (50%) developed a complication, compared with 6 (55%) in the COVID-19 negative group (p>0.05). The commonest complication in both groups was respiratory infection. Three COVID-19 positive patients (37.5%) required intensive care unit (ICU) admission, compared with 4 (36%) in the COVID-19 negative group (p>0.05). The average time between surgery and discharge was 19 and 10 days in COVID-19 positive and negative groups respectively (p=0.02). In the COVID-19 positive group, smoking, abnormal BMI, preoperative oxygen requirement, presence of fever and oxygen saturations <95% correlated with increased risk of complications. Conclusion Emergency instrumented spinal surgery in COVID-19 positive patients was associated with increased length of hospital stay. There was no difference in occurrence of complications or ICU admission. Risk factors for increased morbidity in patients with COVID-19 included smoking, abnormal BMI, preoperative oxygen requirement, fever and saturations <95%.

The COVID-19 pandemic sent shockwaves to global healthcare systems. First reported in Wuhan City China in December 2019, the virus genome was rapidly characterised 1 Early in the pandemic reports started to emerge of high morbidity and mortality in patients infected with COVID-19 who underwent surgery 4, 5 . There was a lack of testing equipment in many countries, and tests were prioritised for the most sick. Results in these early studies may therefore have been confounded. There are very few studies reporting perioperative outcomes for patients with COVID-19 who undergo surgery, and no studies reporting outcomes for patients with COVID-19 who undergo emergency instrumented spinal surgery. The lockdown in many countries reduced the incidence of patients requiring emergency instrumented spinal surgery and so requirement was less.

In certain circumstances, emergency instrumented spinal surgery is justified in patients with COVID-19 as the alternative may be worse 6 . Delays to operative intervention may result in greater morbidity and mortality for patients [7] [8] [9] . The Royal London Hospital is the UK's busiest major trauma centre (MTC), situated in East London at the heart of the UK outbreak. This made it J o u r n a l P r e -p r o o f uniquely possible to analyse the results of emergency instrumented spinal surgery for patients with COVID-19 during the pandemic.

The primary objectives of this study were to establish the effects of COVID-19 on perioperative morbidity and mortality in patients undergoing instrumented spinal surgery, and to determine risk factors for any increased morbidity and mortality. Secondary objectives were to determine differences between COVID-19 positive and COVID-19 negative patients in postoperative complications, admissions to the intensive care unit (ICU), and duration of hospital admission.

checklist for this section of the manuscript. 10

This retrospective observational cohort study included consecutive patients undergoing emergency instrumented spinal surgery in one National Health Service (NHS) hospital in the UK.

No ethical approval or informed consent was required for this study, it was registered as a service evaluation through the local hospital governance team. Exclusion criteria were: emergency spinal surgery without instrumentation of ≥2 vertebral levels;

patients admitted requiring emergency spinal surgery, but transferred to an external hospital for surgery in order to create hospital capacity at the MTC; patients with COVID-19 symptoms but without confirmatory swab, chest radiography or CT finding. Hospital governance board considered this a service evaluation. We excluded 15 COVID-19 negative patients who underwent spinal instrumentation for trauma during this time, as they were stable patients who were transferred out to a local non-NHS hospital to create capacity in the MTC. Nine other UK specialist spinal centres were contacted to contribute patients to the study, but no spinal operations had been performed on patients with the above inclusion criteria during this time.

Patients were classified as COVID-19 positive in the following circumstances: a positive throatand nose-swab assay using reverse transcriptase-polymerase chain reaction (RT-PCR) for severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) obtained prior to surgery; patient with symptoms of cough and/or fever and, chest radiography and/or CT finding showing COVID-19 changes [9] . Patients were classified as COVID-19 negative if they were asymptomatic with negative throat-and nose-swabs assays using RT-PCR for SARS-COV-2.

Repeat swabs were performed for patients with suspicious clinical symptoms and negative initial swab results.

For each patient, the following data was collected: baseline demographics including age, sex and body mass index (BMI), medical co-morbidities, smoking status, presence of preoperative COVID-19 symptoms, presence of preoperative temperature >37. 

Statistical analysis was conducted using SPSS statistics software v25 ® (IBM, UK). A P-value <0.05 was considered significant. Categorical variables were compared using Fisher's exact test.

Continuous variables were compared using unpaired t-test for normally distributed data, and Mann-Whitney U test for data not normally distributed. BMI status, smoking status, surgical indication, and presence of medical co-morbidities were converted to categorical binomial variables. COVID-19 positive and COVID-19 negative groups were compared for baseline demographics and characteristics. Fisher's exact test was used to compare baseline sex, BMI status, smoking status, injury site, surgical indication, medical co-morbidities, preoperative oxygen requirement, preoperative temperature (fever) and preoperative oxygen saturation. Mann-Whitney U test was used to compare preoperative AIS score and ASA grade. The independent samples T-test was used to compare age and time from admission to surgery.

Postoperative outcomes for the two groups were compared using Fisher's exact test for occurrence of complications and ICU admission, and independent samples t-test for time from surgery to hospital discharge. Postoperative outcomes were correlated to preoperative baseline J o u r n a l P r e -p r o o f characteristics in the COVID-19 positive group. Specifically occurrence of complications and requirement for ICU admission were correlated to presence of preoperative temperature (fever), preoperative oxygen saturation, comorbidities, BMI status, and smoking status. Bivariate correlation test was performed.

Patients in both treatment groups had comparable baseline characteristics (Tables 1 and 2). In the COVID-19 positive group, five patients had been diagnosed by positive nasopharyngeal swab and three by presence of symptoms with characteristic chest radiography or CT. The average time between admission and surgery in the COVID-19 positive and negative groups was 5.5 and 3 days respectively (p=0.25).

There were no mortalities in either treatment group. Four COVID-19 positive patients (50%) developed a complication, compared with 6 (55%) in the COVID-19 negative group (p>0.05) ( Table 3 ). The commonest complication in both groups was respiratory infection. In the COVID-19 positive group, smoking, abnormal BMI, preoperative oxygen requirement, presence of fever, preoperative oxygen saturations <95% and presence of co-morbidities correlated with increased risk of complications. Length of stay was greater in the COVID-19 positive group. We found risk factors associated with increased risk of complications for COVID-19 positive patients were smoking, abnormal BMI, preoperative oxygen requirement, presence of fever and preoperative oxygen saturations <95%.

London was the epicentre for the UK outbreak. The Royal London Hospital is the UK's busiest MTC and a COVID-19 specialist hub. Tower Hamlets, our local borough was the epicentre of the London outbreak making our geographical location ideal to investigate the effect of COVID-19 in emergency instrumented spinal surgery. Emergency spinal procedures performed in this study followed international consensus guidance on recommended indications for surgery 6 . We had relatively few patients in the COVID-19 negative group. The reason for this was that patients who required emergency spinal instrumentation and were deemed clinically stable were transferred out of the MTC to a local hospital that only admitted COVID-19 negative patients. This was done to ensure capacity was created and maintained in the MTC. Patients in this study therefore represented a sample of the most severely affected hospitalised patients, mostly polytrauma, and explain why complication rates were comparatively high in the literature 7-9 .

In the early weeks of the UK outbreak, there was a shortage of testing kits. We therefore included patients in the COVID-19 positive group who either had a positive swab prior to surgery, or had a J o u r n a l P r e -p r o o f classical symptom (fever or cough), no other source of infection and chest radiography and/or CT showing characteristic features 11 . The definitive test for SARS-CoV-2 is the real-time RT-PCR test, however sensitivity is low. A study of 205 patients with positive RT-PCR assays for serum SARS-COV-2 found sensitivity of RT-PCR for viral RNA was 93% with bronchoalveolar lavage, 72% with sputum, 63% with nasal swabs and 32% with throat swabs 12 . The sensitivity of RT-PCR assays in polytrauma and surgical patients remains unknown and is thought to be lower.

Sensitivity for various diagnostic methods varies with disease stage and degree of viral multiplication 13 . False negatives are a real clinical problem with RT-PCR SARS-CoV-2 swabs, and several negative tests might be required in a single case to be confident about excluding the disease. For hospitalised patients, radiographic confirmation has a higher sensitivity.

Chest CT is a sensitive diagnostic method for detection of SARS-CoV-2. In a series of 51 patients with chest CT and RT-PCR assay performed within 3 days, the sensitivity of CT for COVID-19 infection was 98% compared to RT-PCR sensitivity of 71% (p<.001) 13 . Similarly chest radiography for hospitalised patients is a sensitive diagnostic tool. In patients with COVID-19 requiring hospitalization, 69% had an abnormal chest radiograph at the initial time of admission, and 80% had radiographic abnormalities during hospitalization 14 . There is no perfect diagnostic test for COVID-19 that has both high sensitivity and high specificity. In the early months of the pandemic, when many countries were short of testing equipment, symptoms and radiological confirmation were used as the recommended basis for clinical diagnosis 15 .

Many studies have demonstrated high mortality rates for patients with COVID-19 undergoing emergency surgical procedures, as high as 20-30% 5 . This has made many surgeons apprehensive about operating on COVID-19 patients. We contacted nine other UK specialist spinal centres to contribute patients to the study, but no operations had been performed on COVID-19 patients with the above inclusion criteria, largely due to concerns about increased perioperative mortality and morbidity. This demonstrates the uniqueness and rarity of this patient cohort.

We had no mortalities in either of our surgical groups at 30 days. Safety is a founding paradigm of surgery, and so understanding risk is important for future departmental planning should a second wave of the pandemic occur 16 . Our results suggest that for life or limb threatening emergency procedures, emergency spinal surgery can be undertaken without a substantial increase in mortality under certain conditions. We still advocate that all patients should be consented for the possibility of catching COVID-19, disease progression, ICU admission and death. Patients at particular risk for adverse perioperative outcomes are those with an abnormal BMI, smokers, patients requiring preoperative oxygen and those with preoperative fever (>37.5 o C) and oxygen saturations <95%.

The commonest complication we encountered was respiratory infection. Zhou et al. reported on 191 ICU patients with COVID-19 and showed that respiratory failure (54%) was the commonest complication 17 . Cardiorespiratory and renal complications are common in patients with COVID-19 due to the high numbers of angiotensin converting enzyme-2 (ACE-2) receptors within the alveoli epithelial cells, myocardium and kidney 18 . The COVID-19 protein envelope has a high affinity to these membranous receptors, enabling the virus to enter host cells and replicate. Smoking upregulates ACE-2 receptors. This is one of many mechanisms through which smoking is thought to adversely affect clinical outcomes.

Our current approach to management of patients with COVID-19 requiring emergency spinal surgery is to assess each patient on an individual basis, balancing risks of respiratory compromise from COVID-19, with risks of not operating which may be greater. We liaise closely with our intensivists for this purpose to make a multidisciplinary decision.

This is a retrospective observational study with low patient numbers. This is expected given the emergency context of the pandemic, short time frame and complexity of surgery involved, J o u r n a l P r e -p r o o f however this makes our study vulnerable to bias, confounding and type 2 statistical error.

Accordingly, our results should be interpreted with caution. We did not perform a power analysis as we had wanted to include as many patients in the short time frame as possible. Many published clinical studies on COVID-19 include a wide heterogeneity of included patients. In our study, patients represented a select cohort of the most severely affected hospitalised spinal patients requiring instrumented surgery. To mitigate differences between groups, we excluded patients deemed more stable who could be transferred out to a neighbouring private hospital.

This introduced sample bias. We found baseline characteristics between groups were similar; one explanation for this is type 2 statistical error. Our sample was too small for multivariate analyses; therefore the results were confounded. Randomised trials are not ethical or practical, and despite inherent weaknesses, we believe our study provides an important and timely insight into perioperative outcomes for patients with COVID-19 who undergo emergency instrumented spinal surgery. We advocate multicentre trials and meta-analyses using collaborative data for future studies on this rare patient cohort.

Emergency instrumented spinal surgery in COVID-19 positive patients was associated with increased length of hospital stay. There was no difference in occurrence of complications or ICU admission. Risk factors for increased morbidity in patients with COVID-19 included smoking, abnormal BMI, preoperative oxygen requirement, fever and saturations <95%. Under certain conditions, our results suggest that for life or limb threatening emergency procedures, emergency spinal surgery can be undertaken without a substantial increase in perioperative mortality or morbidity. 

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