Application of Valsalva manoeuvre to facilitate resection of intradiploic arachnoid cyst.

Non-traumatic intradiploic arachnoid cyst (IAC) is a rare benign skull lesion first described by Weinand et al.[1] It is presumed to be congenital in origin, and the natural history or prognosis of this condition is not well-known owing to its rarity.[2] IAC contains cerebrospinal fluid, but it is not strictly confined to the diploic space as there is always a communication with the intracranial subarachnoid space.[3] Small, asymptomatic lesions do not require any active intervention and are followed-up radiologically. Surgery is indicated for progressive lesions causing local pain or localized swelling.[24]

A 16-year-old female admitted with occipital headache was diagnosed with an occipital non-traumatic IAC [Figure 1]. Resection of the cyst was carried out under general endotracheal anaesthesia in the prone position. During surgical resection, the periphery of the cyst was not easily accessible. Hence, brief Valsalva manoeuvre was applied to facilitate resection (delivery) of the lesion.[5] The Valsalva manoeuvre was applied intraoperatively three times for successful delivery of the cyst, and was well tolerated, without any adverse haemodynamic event.

Figure 1

T2-weighted magnetic resonance imaging showing cyst lesion in the occipital region with herniation of the cerebellum into the cyst

Surgical resection of the non-traumatic IAC involves resection of the pedicle of the cyst and repair of dural defect. The Valsalva manoeuvre transiently increases intracranial pressure (ICP), and can be used to facilitate the trans-sphenoidal resection of pituitary tumours and for confirmation of venous haemostasis. Valsalva manoeuvre can also facilitate resection of fourth ventricular neurocysticercosis.[5] In the present case, the manoeuvre helped extrusion of the IAC. The basis of the application of Valsalva manoeuvre to facilitate delivery of the cyst is that the increased ICP may be transmitted to the IAC through a communication between the IAC and the intracranial subarachnoid space, thereby making the lesion more conspicuous. However, one needs to be vigilant about possible haemodynamic changes during the manoeuvre. Valsalva manoeuvre may lead to transient episodes of hypotension and tachycardia followed by hypertension and bradycardia. Application of the manoeuvre during posterior fossa surgery has been reported to cause ventricular arrhythmias.[6] Since non-traumatic IAC is a very rare entity, no data specific to the anaesthetic management of this condition is available. To the best of our knowledge, this is the first report of successful application of Valsalva manoeuvre to facilitate resection of an IAC. Hence, we suggest that the Valsalva manoeuvre could facilitate surgical resection of otherwise inaccessible IACs.