Contralateral progression after unilateral evacuation of bilateral chronic subdural hematomas: the volume relation ratio as prognostic factor?

Abstract

OBJECTIVEUnilateral evacuation of bilateral chronic subdural hematomas (bcSDHs) is associated with higher retreatment rates than an initial bilateral intervention. One reason for that is a possible progression in the size of the contralateral side after unilateral treatment. Thus, the authors focused their study on finding predictors of the need for contralateral retreatment.METHODSAll patients who had undergone unilateral or bilateral evacuation of bcSDHs in the Department of Neurosurgery at the University Hospital of St. Poelten during a 5-year period (7/2012 to 6/2017) were retrospectively identified. The preoperative hematoma volume was calculated using the XYZ/2 method.RESULTSOf a total of 103 patients with bcSDHs, 61 patients underwent bilateral evacuation and 42 patients underwent unilateral evacuation. The retreatment rate after bilateral evacuation was significantly lower than that after unilateral evacuation (14.8% vs 31%, respectively; p = 0.049). Contralateral retreatment after unilateral evacuation was necessary in 9 patients (21.4%). The preoperative contralateral hematoma volume was significantly higher in those patients who needed contralateral retreatment after initial unilateral evacuation (68.4 cm3 vs 27.4 cm3, respectively; p < 0.001). Furthermore, the so-called volume relation ratio created by dividing the smaller by the larger hematoma volume was significantly higher when contralateral retreatment became necessary (0.56 vs 0.21, respectively; p < 0.001).CONCLUSIONSPatients needing evacuation of bcSDHs should be considered for primary bilateral evacuation if the hematoma volume on the smaller side is greater than 40 cm3 and the subsequent volume relation ratio is greater than 0.4.

Risk factors for need of reoperation in bilateral chronic subdural haematomas

“…There’s also evidence pointing to the minicraniotomy having a place in the treatment of recurrent more organised CSDHs [ 2 , 13 , 18 , 25 ]. Identical recurrence rates have been described previously in other studies [ 3 , 19 ]. It is also important to note that intuitively, the reoperation rate of bCSDH will be higher compared to unilateral CSDH since there are two CSDHs.…”

“…Our study confirms and is in line with the results observed in the Danish study with unilateral evacuation of bCSDH significantly increasing the risk of reoperation. Our study is to our knowledge the largest retrospective study which has investigated bCSDH concerning the reoperation rate with respect to the choice of surgical approach [ 3 , 16 , 19 ].…”

“…Some studies have tried to quantify and isolate the volume of the contralateral side to predict the need of bilateral evacuation. Two studies found that contralateral haematomas with a volume consisting of more than 40 cm 3 and 37.84 cm 3 respectively warranted consideration for bilateral evacuation [ 19 , 21 ]. As has been previously postulated in several studies, there seems to be a relationship between the two haematomas in bCSDH.…”

“…There has recently been a surge in research concerning bCSDH in order to find evidence for standardised treatment guidelines [ 3 , 16 , 19 , 24 ]. It has previously been highlighted that bCSDHs themselves are risk factors for recurrence [ 3 , 5 , 10 , 14 ].…”

Unilateral drainage of bilateral chronic subdural hematoma

“…Two recently published articles studying the results of unilateral surgical evacuation in bCSDH 25,26 comprising a total of 394 cases stated that currently the decision to perform a unilateral evacuation on bCSDH is based on the relative volume of each subdural collection and in the presence of lateralizing clinical signs. The unilateral procedure in bCSDH was found in these studies, to be an independent risk factor for reoperation, a fact that led these authors to recommend the bilateral evacuation from the start.…”