DOI: 10.5061/dryad.q83bk3jgr
title: Comparison of outcomes of neurosurgical operations performed before and during the COVID-19 pandemic: a matched cohort study

description: Objective To determine how the first wave of the COVID-19 pandemic
 affected outcomes for all operatively managed neurosurgical patients, not
 only those positive for SARS-CoV-2. Design Matched cohort (pairwise
 method). Setting A single tertiary neurosurgical referral centre at a
 large UK Major Trauma Centre. Participants During the first COVID-19 wave,
 231 neurosurgical cases were performed. These cases were matched to cases
 from 2019. Cases were matched for age (±10 years), primary pathology and
 surgical procedure. Cases were excluded from analysis if either the age
 could not be matched to within 10 years, or the primary pathology or
 procedure was too unique. After exclusions, 191 cases were included in
 final analysis Outcome measures Primary outcomes were 30-day mortality and
 postoperative pulmonary complications. Secondary outcomes included Glasgow
 Outcome Score (GOS) on discharge, length of stay (LoS), operative and
 anaesthetic times and grade of primary surgeon. An exploratory outcome was
 the SARS-CoV-2 status of patients. Results There was no significant
 difference between the pandemic and matched cohorts in 30-day mortality,
 pulmonary complications, discharge GOS, LoS, operative or anaesthetic
 times. There was a significant difference in the variation of grade of
 primary surgeon. Only 2.2% (n=5) of patients had a SARS-CoV-2 positive
 swab. Conclusion During the first UK wave of the COVID-19 pandemic, the
 mortality, morbidity and functional outcomes of operatively managed
 neurosurgical patients at University Hospitals Birmingham were not
 significantly affected compared with normal practice. The grade of primary
 surgeon was significantly more senior and adds to the growing body of
 evidence that demonstrates how the pandemic has negatively impacted UK
 surgical training. Mixing COVID-19 positive, unknown and negative cases
 did not significantly impact on outcomes and indicates that further
 research is required to support the implementation of evidence-based
 surgical pathways, such as COVID-light sites, throughout the next stage of
 the pandemic.
description: <strong>Study
 design</strong><br> The study was undertaken at the Queen
 Elizabeth Hospital Birmingham (QEHB) as a single-centre, matched cohort
 study. The QEHB is the largest hospital within the University Hospitals
 Birmingham (UHB) Foundation Trust, is one of three regional adult
 neurosurgical units in the West Midlands and is responsible for a mixed
 urban and rural population. <strong>Participants</strong><br> Operations performed during the initial stage of the pandemic (19th March 2020 to 1st June 2020) were matched to pre-pandemic cases (11th March 2019 to 11th September 2019). The pandemic time period was chosen as this was the interval in which elective neurosurgery cases at UHB were cancelled and will be referred to as the “initial pandemic phase” from here onwards. Cases were matched in a pairwise fashion for age at time of procedure (+/- 10 years), primary pathology and procedure. Primary pathology included severity where appropriate; for example, poor grade subarachnoid haemorrhage (SAH) was matched with another SAH of equivalent poor grade. Procedure was also matched to site where significant; for example a left-sided frontal craniotomy was matched with another left-sided frontal craniotomy rather than a right-sided. Ward-based procedures such as lumbar drain and ICP bolt insertion were not included. Cases were deemed unmatchable and were excluded from analysis if either the age could not be matched to within 10 years or the primary pathology or procedure was too unique. <strong>Procedures</strong><br> Cases were identified by performing a search of the Galaxy electronic operating theatre system for all operations carried out under a neurosurgical consultant within the chosen time periods. Galaxy and the Prescribing Information and Communications System (PICS) were then used to collate relevant variables. Demographic data included age and gender. Operative data included name of procedure, grade of primary surgeon and operative time points. Grade of surgeon was defined as junior Senior Registrar (SpR)(ST3-5 or equivalent), senior SpR (ST5-8 or equivalent), fellow or consultant. Pre-operative anaesthetic time was defined as time “into anaesthetic room” to “knife to skin”, operative time was defined as “knife to skin” to “skin closure” and post-operative anaesthetic time was defined as “skin closure” to time “into theatre recovery”. Clinical data included length of hospital stay (LoS) in days, discharge Glasgow Outcome Score (GOS), (10) 30-day mortality, post-operative pulmonary complications and COVID-19 swab status. Swabs were deemed to be positive if SARS-Cov-2 RNA was detected by the standard RT-PCR laboratory test.  <strong>Outcomes</strong><br> PRIMARY OUTCOMES 30-day mortality Post-operative pulmonary complication Primary outcomes were designed to be comparable to the COVIDSurg study.  ADDIN EN.CITE.DATA (8) For 30-day mortality, day of surgery was treated as day 0. Post-operative pulmonary complication was defined as pneumonia, acute respiratory distress syndrome (ARDS), or unexpected postoperative ventilation (any episode of non-invasive ventilation, invasive ventilation, or extracorporeal membrane oxygenation after initial extubation after surgery; or patient could not be extubated as planned after surgery). SECONDARY OUTCOMES Discharge GOS (1-5) Length of stay in hospital (days) Grade of primary surgeon Pre-operative and post-operative anaesthetic time (minutes) Operative time (minutes) The Glasgow Outcome Score is an objective, functional outcome score from 1-5. (11) Favourable GOS was defined as a score of 4 (moderate disability) or 5 (good recovery). Unfavourable GOS was defined as a score of 1 (dead), 2 (vegetative state) or 3 (severe disability). EXPLORATORY OUTCOME COVID-19 status both pre- and post-operatively and the clinical course of positive patients. <strong>Statistical methods</strong><br> The study was conducted and reported in line with STROBE guidelines for cohort studies. (12) Continuous data were tested for normal distribution prior to analysis. Parametric data are presented as mean with 95% CI, and the unpaired t test used to detect differences between groups. Non-parametric data are presented as median with IQR, and Mann-Whitney used to detect differences between groups. The X2 test was used for categorical data. Missing data points were removed from final analyses. Clinical significance was defined as p&lt;0.05. Analyses were performed using GraphPad Prism software version 8.4.3 for Windows.