Early Post-Operative Morbidity after Chronic Subdural Haematoma: Predictive Utility of POSSUM, ACS-NSQIP and ASA in a Prospective Cohort.

BACKGROUND: Although generally 'benign', long-term survival (LTS) after chronic subdural haematoma (CSDH) is poor in a significant sub-group. Such dichotomy has been compared to fractured-neck-of-femur. However, whilst early post-operative mortality (POMT) is well recorded with CSDH and similar to fractured neck-of-femur (4-8%), scant accurate data exists regarding early post-operative morbidity (POMB). POMB which prolongs length-of-stay (LOS) after major non-neurosurgery is associated with decreased LTS. One recent CSDH study suggested a POMB 'standard' of 10%: i.e. notably less than with fractured-neck-of-femur (45%).

METHODS: POMB was recorded in a novel prospective single-centre cohort after CSDH. The Physiological-and-Operative-Severity-Score-(POSSUM), American-College-of-Surgeons-National-Surgical-Quality-Improvement-Program-(ACS-NSQIP)-score and ASA were assessed as tools for potentially predicting POMB. Receiver-operator -curves-(ROC) were calculated.

RESULTS: POMT was n=3/114 (3%). N=71 POMB events occurred in n=54/114 (47%), with n=27/54 (50%) Clavien-Dindo≥2 severity. Most POMB was 'neurological' (n=47/71, 66%). Age (P=0.01), GCS (P=0.001), Markwalder grade (MG) (P=0.01), hypertension (P=0.047) and/or ≥1 pre-existent co-morbidity (P=0.041) were predictive. LOS (P=0.01) and discharge-mRS (P<0.001) were significantly associated. Predicted and observed POMB with POSSUM were significantly disparate (χ2 =15.23, P=0.001): POSSUM area-under-ROC (AUROC:0.611) was also 'non-discriminatory'. ACS-NSQIP (χ2 =18.51, P<0.001;AUROC=0.629) and ASA (P=0.25) were also non-predictive.

CONCLUSIONS: POMB was frequently disabling, mostly 'neurological', and as frequent and diverse as with fractured-neck-of-femur. POMB was significantly correlated with LOS and discharge-mRS. Surprisingly, POSSUM, ACS-NSQIP and ASA were not predictive, and would not aid consent. Simple parameters (age, GCS, MG, hypertension and/or ≥1 other co-morbidity) were instead predictive. Longitudinal-follow-up will determine whether POMB affects LTS. CSDH, like fractured-neck-of-femur, is distinct.