• Journal of Korean Neurosurgical Society
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• v.65 no.5
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• pp.652-664
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• 2022

The Kernohan-Woltman notch phenomenon (KWNP) refers to an intracranial lesion causing massive side-to-side mass effect which leads to compression of the contralateral cerebral peduncle against the free edge of the cerebellar tentorium. Diagnosis is based on "paradoxical" motor deficit ipsilateral to the lesion associated with radiologic evidence of damage to the contralateral cerebral peduncle. To date, there is scarce evidence regarding KWNP associated neuroimaging patterns and motor function prognostic factors. A systematic review was conducted on Medline database from inception to July 2021 looking for English-language articles concerning KWNP, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The research yielded 45 articles for a total of 51 patients. The mean age was 40.7 years-old and the male/female sex ratio was 2/1. 63% of the patients (32/51) suffered from head trauma with a majority of acute subdural hematomas (57%, 29/51). 57% (29/51) of the patients were in the coma upon admission and 47% (24/51) presented pupil anomalies. KWNP presented the neuroimaging features of compression ischemic stroke located in the contralateral cerebral peduncle, with edema in the surrounding structures and sometimes compression stroke of the cerebral arteries passing nearby. 45% of the patients (23/51) presented a good motor functional outcome; nevertheless, no predisposing factor was identified. A Glasgow coma scale (GCS) of more than 3 showed a trend (p=0.1065) toward a better motor functional outcome. The KWNP is a regional compression syndrome oftentimes caused by sudden and massive uncal herniation and leading to contralateral cerebral peduncle ischemia. Even though patients suffering from KWNP usually present a good overall recovery, patients with a GCS of 3 may present a worse motor functional outcome. In order to better understand this syndrome, future studies will have to focus on more personalized criteria such as individual variation of tentorial notch width.

• Journal of Korean Neurosurgical Society
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• v.60 no.3
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• pp.362-366
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• 2017

Vascular compromise is a well-known consequence of brain herniation syndromes. Transtentorial brain herniation most often involves posterior cerebral arteries. However, isolated involvement of contralateral superior cerebellar artery (SCA) during unilateral impending brain herniation is reported only once and we present another case of this exceedingly rare entity. A 24-year-old man was referred to us with impending herniation due to a multiloculated hydrocephalus, and during the course of illness, he developed an isolated SCA ischemia in the opposite side of the most dilated entrapped horn. In the current article we discuss the probable pathophysiologic mechanisms of this phenomenon, as well as recommending more inclusive brain studies in cases suspected of Kernohan-Woltman notch phenomenon in unilateral brain herniation. The rationale for this commentary is that contralateral SCA transient ischemia or infarct might be the underdiagnosed underlying pathomechanism of ipsilateral hemiparesis occurring in many cases of this somehow vague phenomenon.