Asazuma Classification [Neurosurgery Wiki]

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====== Asazuma Classification ======


Asazuma et al.
((Asazuma T, Toyama Y, Maruiwa H, Fujimura Y, Hirabayashi K. Surgical strategy for cervical dumbbell tumors based on a three-dimensional classification. Spine (2004) 29:E10–4. doi:10.1097/01.BRS.0000103662.
13689.76))
devised a [[schwannoma classification]] system for cervical dumbbell-shaped tumors that consisted of nine categories. An important drawback of their classification system is that it cannot be used for [[thoracic spinal schwannoma]]s or lumbar schwannomas, which are as common as cervical schwannomas.

Asazuma et al. classification system for [[dumbbell spinal schwannoma]]:

{{schwannomaclasificacion.jpg|}}

Type 1 intradural extradural restricted to the spinal canal. The constriction occurs at the dura.

Type II are all extradural, and are subclassified as:

IIa do not expand beyond the neural foramen. 

IIb inside spinal canal + paravertebral.

IIc foraminal + paravertebral.

Type IIIa are intradural and extradural foraminal, IIIb are intradural and extradural paravertebral.

Type IV are extradural and intravertebral.

Type V are extradural and extralaminar with laminar invasion.

Type VI show multidirectional bone erosion.

Craniocaudal spread: IF & TF designate the number of intervertebral foramina and transverse foramina involved, respectively (e.g. IF stage 2 = 2 foramens).

Schwannomas involving C1 & C2: May involve vertebral arteries and require additional caution.