The Operation for Echinococcal Infections of the Central Nervous System in Children

To prevent the spilling of scolices and possible contamination of adjacent tissues, which may lead to the recurrence of multiple cysts, every attempt should be perfomed at best in the light of the criteria existing in literature that primary hydatid cysts are usually solitary and contain fertile scolices and secondary ones are multiple and infertile (9).

Patient Positioning

• Standard positioning for craniotomy: No special consideration is necessary in regard to classical neurosurgical techniques.
• Head fixation: Not always required.

Surgical Approach

The choice of surgical approach depends on several factors, including the location, size, and multiplicity of the cysts (1).

• Large craniotomy: A large craniotomy is performed that is greater than the diameter of the cyst to be removed. At the least, the longer diameter of craniotomy must be larger than the cyst’s diameter.
• Exposure of cyst surface: A cortical incision is carefully made, and the atrophic cortex overlying the cyst is dissected to expose the cyst’s surface.

Intervention

There are two methods for removing a primary hydatid cyst in the brain.

Dowling-Orlando Technique

• Lower the head of the operating table: The head of the operating table is lowered to gain the assistance of gravitational forces for the easy release and intact evacuation of the cyst once it has been freed.
• Gentle dissection to develop a plane between the cyst and brain: The surgical plane between the cyst and parenchyma is gently developed with cotton pads, and it must be done circumferentially. Electrocautery is avoided for fear of rupturing the cyst’s membrane. Every effort should be made to avoid rupture of the cyst as this may cause anaphylactic shock, chemical meningitis, and even death. It can also result in spillage of the scolices into the ventricle with a disastrous development of multiple hydatid cysts throughout the CSF system (19, 21).
• Hydrodissection: Dowling’s technique employs the use of hydrostatic assistance to dissect the fragile cyst wall from the brain parenchyma., and then a soft-tipped or rubber catheter is inserted into the plane. The continuous irrigation with saline through the catheter and slow advancement of the cotton pads or strips may allow the cyst to be delivered with no ruptures. (9, 46, 47).

PAIR Technique (cyst aspiration)

• No description of use for CNS disease
• Used when avoidance of extensive dissection desired: Another surgical technique mentioned in the literature and used in problematic cases is the tapping procedure, i.e., puncture with a needle followed by aspiration during surgery. This technique can be used for deep-seated and tightly surrounded cysts that cannot be removed by irrigation. 
• Introduction of needle into cyst
• Contents of cyst aspirated: The entire content of the cyst is then aspirated.
• Removal of cyst’s membrane: The cyst’s membrane is separated from the surrounding parenchyma and removed totally.
• Irrigation after removal: Although the area of spillage is irrigated with an antiscolicidal solution to prevent anaphylactic complications and recurrences, each puncture invariably leads to some spillage of the contents into the surgical area.  As a result the potential for secondary cyst recurrences is very high.

Closure

• Standard closure: No special consideration with regard to classical neurosurgical techniques

Spinal hydatid disease

• Wide excision of involved spine: Radical surgery is the keystone of treatment, but complete removal of spinal hydatid cysts is rarely accomplished in a single operation. This is mainly due to the extensive bone invasion, spillage, and implantation of live vesicles, and the high rate of local recurrence. Residual diseased vertebral bodies and adjacent tissues make total excision of the disease rare. Consequently, surgery is followed by treatment with albendazole.
• Chemotherapy alone not favored: Among the authors writing on the issue, there is a consensus that isolated chemotherapy with albendazole is insufficient to cure the osseous lesions of hydatid disease (33).