http://thejns.org/doi/pdf/10.3171/2012.6.GKS12697My interpretation of this is that, like a potato an acoustic neuroma has a skin.
The Potato skin if you like would often adhere to the brainstem, facial and trigeminal nerve.
Debulking involves cutting as much of the potato away as possible, while leaving a safety margin
Possibly removing 90% of the potato and the potato skin with it.
This is potentially tricky when the potato skin is adhering to your brainstem and nerves.
This new approach is not what has been called debulking in the past. It makes no attempt to pull or separate the tumour from the brainstem, or nerves.
A hole is made in the "potato" tumour and they remove as much of the inside of the potato/tumour as possible with microsurgical nibbling tools, and the potato/tumour skin is left behind relatively untouched!
Gamma knife is then used on the left over skin of the tumour.
Could be a whole new way of thinking and better outcomes for people with large AN's