Risk Factors of Yamamoto et al for Recurrence of a Chronic Subdural Hematoma

 

Parameters associated with recurrence based on multivariate analysis:

(1) "multiplicity" of hematoma cavities (hematoma with inhomogeneous contents and a high-density septum running between inner and outer membranes)

(2) history of seizure

(3) width of the hematoma at its thickest point

(4) history of diabetes mellitus

Parameter	Finding	Points
multiplicity of hematoma cavities	absent	1
	present	0
history of seizures	absent	0
	present	1
width of the hematoma	thin	0
	thick (see below)	1
history of diabetes mellitus	absent	1
	present	0

 

where:

• The odds ratio for recurrence in the multivariate analysis increased 1.22 for each mm of thickness. I used >= 4 mm in the implementation, but this can be adjusted.

 

number of risk factors =

= SUM(points for all 4 parameters)

 

Interpretation:

• minimum number of risk factors: 0

• maximum number of risk factors: 4

• The risk of recurrence is greater when more risk factors are present.