**10. Surgical technique**

The Kocher point is the most common access site for ETV [31], it is located 2 cm lateral to the midline and 2 cm anterior to the coronal suture [33]. Other access points

#### **Figure 14.**

*Premamillary membrane and its relationship with the diencephalic portion of the membrane of Liliequist membrane (LM).*

#### **Figure 15.**

*Ventricular system and relationship with the endoscopic access points to the floor of the 3rd ventricle.*

can be used, depending on the associated pathology [32]. In infants with a patent fontanelle, this corridor can be used by making the incision at the lateral end of the fontanelle rhombus (**Figure 15**) [33].

#### **10.1 Other access points**


5.Tubbs.

6.Kocher.

#### **10.2 Before starting**


The insertion of the endoscope must be done gently, without exerting pressure on the endoscope, bearing in mind the distance measured in the neuroimaging, when reaching the ventricle and even though the brain parenchyma does not offer resistance to the insertion of the endoscope, a sensation can be felt. Change in resistance to the advancement of the endoscope.

Upon reaching Monroe's foramen, we must observe the landmarks of this point: choroid plexus, anterior septal and thalamus striate vein, and fornix. It is convenient at this point to observe all possible anatomical details of the third ventricle.

When descending to the third ventricle, the landmarks must be recognized: mammillary bodies, infundibular recess, and premammillary membrane. At this point, it is convenient to transilluminate the premammillary membrane to try to observe the anatomy of the basilar artery.

Perforation of the floor of the third ventricle must be done with a blunt object, it can be the coagulator (without activating heat), it has been mentioned that heat can generate an inflammatory response that leads to closure of the fenestration [31], or the clamp forceps, others have mentioned the use of laser as an option to perform fenestration [34]. The initial ostomy should be the size of the perforating object, it is also convenient to maintain irrigation at this time and observe if there is bleeding, gently remove the perforating object and if there is no bleeding, expand the ostomy with a Fogarty 3 or 4 catheter. If you do not have a Fogarty catheter, this amplification can be done with forceps, always gently and patiently, or with the coagulator moving on the edge of the ostomy from right to left from front to

back, very gently and making sure not to contact neural structures with the highest part of the endoscope.

**The opening of the Liliequist's membrane** (LM) is of vital importance for the success of the ETV, for which special attention should be paid to the prepontine space and to visualize as much as possible the characteristics of this membrane for its opening [31, 35, 37, 42], after this opening, the interpeduncular cistern and the prepontine cistern should be visualized, to inspect that there is no other arachnoid membrane that interferes with the passage of CSF.

#### **11. TVE/VP shunt comparison**

ETV was associated with a statistically significant lower risk of procedure-related infection compared to shunt [21]. It is generally accepted that true differences exist regarding complication rates among centers or among individual neurosurgeons, according to their personal experience [59, 65, 66].

Despite the fact that the calculation of the Costs to compare TVE vs. VP shunt may vary from country to country, ETV represents less economic costs if it is taken into account that no device is left, and the number of surgeries per patient may be less in the patient who receives TVE; however, there are not enough relative studies to establish a significant difference, since various studies that have been carried out were carried out in countries with different economic incomes and did not show statistical significance in terms of costs [67] others compared and the VP shunt, endoscopic third ventriculostomy (ETV) was proven to be better in terms of infection, length of hospital stay, cost-effectiveness, and complication rate [68].

Much more evidence and comparative studies are needed.

#### **12. ETV & choroid plexus coagulation (CPC)**

It may become an efficient treatment for obstructive HCP in infants [69]. However, the etiology of the hydrocephalus, the age of the patient, and the extent of coagulation of the choroid plexuses must be considered [70–72]. These factors can influence the results.

#### **13. Conclusion**

ETV is a safe, effective procedure, for many years included as one of the two surgical alternatives for hydrocephalus. In the pediatric patient with great value. In low-income countries, ETV represents an excellent alternative, where a wide variety of newer and more sophisticated shunting systems, self-regulating systems, or antibiotic-impregnated systems are not available. On the other hand, it has shown a lower frequency of complications and it is not necessary to leave any foreign body in the patient. Infections in shunt systems are common infections that require several days of stay, with high hospitalization and drug costs, and with functional complications derived from neuroinfection, especially in children under 1 year of age. ETV infections have been shown to be very rare and respond well to antibiotic treatment. For all these reasons, ETV should be considered the first treatment option for obstructive hydrocephalus in pediatric patients.

*Frontiers in Hydrocephalus*
