Intracranial Hydatid Cyst: Removal by Dowling's Technique of Hydrodissection.

Sir,

A 4-year-old boy was admitted to pediatric emergency for focal seizures with secondary generalization for 5 months. Contrast-enhanced magnetic resonance imaging showed a cystic lesion of 4.38 cm × 4.55 cm in the right temporal lobe suggestive of hydatid cyst, and craniotomy with removal of the cyst was planned.

The patient underwent right frontotemporal craniotomy. Dura was opened circumferentially away from the cyst, and the cyst was seen in the right temporal lobe covered by atrophic cortex. Cotton patties soaked in hypertonic saline were placed around the cyst. The plane between cortex and cyst wall was delineated. Catheter tip introduced in this plane irrigation with saline was started. To facilitate removal, the cyst was made gravity dependent by tilting head end of the table down by 10°–20°. Gradually, the cyst started separating from the parenchyma and was eventually separated from the cortex as a whole without rupture and delivered in a bowl. Postoperative recovery was uneventful, and the patient was discharged on albendazole (dose: 15 mg/kg/d in two divided doses) for 3 months.

The technique of hydrodissection was originally described by Dowling and Orlando in 1929. It involves: (1) skin incision in large flaps, (2) craniotomy, (3) cortisectomy of no less than three-fourth of the larger diameter of the cyst, (4) use of warm hypertonic saline (3%) in the surgical borders between the brain and the cyst, and (5) cyst delivery. The most important step is cortisectomy and identification of plane between cyst wall and cortex. It is considered to be a safe method for complete cyst removal as also seen in our case, avoiding intraoperative rupture of the cyst leading to spillage of cyst contents, anaphylactic shock, and mortality immediately and recurrence of disease later on. It can be done even in very large cysts which are located superficially. However, it is not immune from the complications of cyst rupture.[12]

The use of antihelminthic agents such as albendazole, mebendazole, and praziquantel in the management of liver hydatid cysts is well documented in literature; however, there is very little evidence for the same in intracranial hydatidosis, and there are concerns about the penetration of these drugs across the blood–brain barrier and the cyst capsule. Moreover, albendazole has been reported ineffective in cases of large cerebral hydatid cysts [Figures 1 and 2].[3]

Figure 1

Removal of gliotic parenchyma held by forceps

Figure 2

Hydatid cyst being separated form cortex by hydrodissection

PAIR (puncture, aspiration, injection, reaspiration) is another technique described for surgical removal of hydatid cysts. It involves puncture and needle aspiration of cyst contents, injection of a scolicidal agent for 20–30 min, and reaspiration and final irrigation. It can be done in cortical as well as deep-seated cysts; however, there is an increased risk of cyst rupture.[4] Different scolicidal solutions used in PAIR include hypertonic saline (20%), 3% hydrogen peroxide, 1.5% cetrimide-0.15% chlorhexidine, 95% ethyl alcohol, and 10% polyvinylpyrrolidone-iodine.

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Conflicts of interest

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