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P-POSSUM scoring system for mortality prediction in general neurosurgery.
W Chen1, J W H Fong, C R P Lind
1West Australian Neurosurgical Service, Sir Charles Gairdner Hospital, 1st Floor, G Block, Hospital Avenue, Nedlands, Western Australia 6009, Australia. wchen@iinet.net.au <wchen@iinet.net.au>
The Portsmouth-Physiological and Operative Severity Score for enUmeration of Mortality and morbidity (P-POSSUM) model, combined with the West Australian (WA) classification, accurately predicts mortality in general neurosurgery. This tool aids in quantifying preoperative risk for meaningful surgical outcome comparisons.
Area of Science:
- Neurosurgery
- Surgical Outcomes Research
- Medical Auditing
Background:
- The Physiological and Operative Severity Score for enUmeration of Mortality and morbidity (POSSUM) and its Portsmouth predictor equation (P-POSSUM) are validated in general and vascular surgery.
- P-POSSUM showed predictive value in elective craniotomies but requires validation in other neurosurgical subspecialties.
- The West Australian (WA) classification was developed for all neurosurgical procedures.
Purpose of the Study:
- To validate the P-POSSUM scoring system, incorporating the WA classification, for predicting mortality in a broad range of neurosurgical procedures.
- To compare the predictive accuracy of the WA P-POSSUM model against the standard POSSUM and elective craniotomy P-POSSUM classifications.
- To assess the utility of the P-POSSUM model with WA classification for mortality audits in general neurosurgery.
Main Methods:
- Retrospective review of case notes and laboratory results for 531 consecutive neurosurgery patients.
- Application of POSSUM and P-POSSUM mortality equations to the collected patient data.
- Comparison of observed mortality rates with predicted rates from different P-POSSUM models.
Main Results:
- The observed mortality rate was 4.52%.
- The WA P-POSSUM model predicted a mortality rate of 4.58%, showing excellent agreement (p>0.951).
- WA P-POSSUM was significantly more predictive than WA POSSUM (10.9%, p<0.0001) and elective craniotomy P-POSSUM (5.8%, p<0.198).
Conclusions:
- The P-POSSUM model, when integrated with the WA classification, demonstrates strong potential for accurate mortality prediction in general neurosurgery.
- This validated model can serve as a valuable tool for preoperative risk quantification in neurosurgical audits.
- The P-POSSUM with WA classification facilitates meaningful comparisons of observed death rates among surgeons and departments.
