In total, 171 patients with cSDH were admitted during the study period. The total number of cSDH patients admitted during the 2020 lockdown period were similar to the same period 1 year ago, in which 86 were admitted from 1 March 2020 to 30 April 2020 (the 2020 group) and 85 were admitted from 1 March 2019 to 30 April 2019 (the 2019 group). The age was comparable at 76.0 (44–102) years old for the 2020 group versus 78.2 (41–101) years old for the 2019 group. The majority of the cSDHs were male, which accounted for 73.26% (63/86) in the 2020 group versus 84.71% (72/85) in the 2019 group.
Sixty-eight cSDH patients in the 2020 group and 69 in the 2019 group were elective admissions for scheduled scans for the detection of any development of cSDH (from a previous aSDH or tSAH) or for monitoring any progression or recurrence of a previously thin cSDH. These groups of patients were excluded from the analysis according to the inclusion and exclusion criteria. For these elective admissions for scheduled scans for detection of any progression of cSDH or recurrence, 3 out of 68 (4.54%) of the cSDH patients in the 2020 group and 0 out of the 70 (0%) in the 2019 group required burr hole drainage.
Sixty-six cSDH patients in the 2020 group and 70 in the 2019 group were discharged from the hospital the same day after clinical assessment and undergoing computed tomographic (CT) scan the same day. 23.3% (20/86) cSDH patients in the 2020 group versus 17.7% (15/85) in the 2019 group required more than 1-day inpatient hospitalisation for the treatment of cSDH (p = 0.363).
20.9% (18/86) cSDH patients in the 2020 group versus 18.8% (16/85) in the 2019 group were emergency admissions (p = 0.730). These patients were included for analysis as they did not fulfill the exclusion criteria. For the emergency admissions, 94.4% (17/18) of cSDH patients in the 2020 group versus 93.8% (15/16) in the 2019 group required burr hole drainage during the same admission episode (p = 0.816).
For the detailed analysis of 18 symptomatic cSDH patients in the 2020 group who required burr hole drainage, eight had no history of head injury, one was intracranial hypotension, and nine had a history of head injury, in which five had an interval preceding head injury with attendance to A&E and CT head performed. For the 2019 group with 16 symptomatic cSDH, seven had no history of head injury and nine had a history of head injury, in which six had an interval preceding episode of head injury.
The average time between head injury and the diagnosis of cSDH was 29.4 days (17 to 42 days, SD 8.59 days) in the 2019 group for the six patients who had a clear history of a preceding head injury, versus 56.6 days (49 to 74 days, SD 9.83 days) for March to April 2020 with five patients, which was significantly longer (p = 0.00703).
For the Markwalder grade upon admission, there was no significant difference between the two groups. The median Markwalder grade at admission was 1 for both groups. For the 2020 group, 75% of the admission Markwalder grade was 1 and 25% had an admission Markwalder grade of 2. For the 2019 group, 70% had an admission Markwalder grade of 1 and 30% had a Markwalder grade of 2 (p = 0.354).
The overall length of stay in the acute hospital was 8.9 days (4 to 19 days) in the 2020 group versus 9.2 days (2 to 25 days) in the 2019 group (p = 0.425).
The functional outcomes in terms of mRS upon discharge were comparable, in which 60% (12/20) in the 2020 group had good outcomes (mRS 0–3), versus 53.3% (8/15) in the 2019 group (p = 0.694).