Endoscopic Septostomy

Stefania Acerno, Filippo Gagliardi, Elena V. Colombo, Cristian Gragnaniello, Anthony J. Caputy, and Pietro Mortini

52.1 Introduction

The endoscopic septostomy is a minimally invasive, intraventricular endoscopic procedure. It allows creating a communication between both the lateral ventricles by opening the septum pellucidum. It is indicated in case of obstructive mono-ventricular hydrocephalus.

Surgical access to the lateral ventricle is just lateral as compared to the standard approach for the placement of an external ventricular shunt.

52.2 Indications

• Mono-ventricular hydrocephalus due to tumoral or membranous (inflammatory, post-hemorrhagic) obstruction in the region of foramina of Monro or fornix.

• Cysts of the septum pellucidum.

• Multi-loculated cystic hydrocephalus.

52.3 Patient Positioning (Fig. 52.1)

• Position: The patient is positioned supine with the head fixed to a three pins Mayfield head-holder.

Fig. 52.1 Patient positioning and landmarks.
Abbreviations: Coronal suture (blue line).

• Body: The body is placed parallel to the horizontal plane in neutral position.

• Head: The head is flexed 30° and the neck is kept in straight position.

52.4 Skin Incision (Fig. 52.1)

• Linear incision

◦ Incision is located just in front of the coronal suture, according to the selected entry point (see burr hole).

◦ The incision is 3 cm long.

• C-shaped incision

◦ The C-shaped incision is based toward the superficial temporal artery.

◦ It is preferred if a cerebro-spinal fluid (CSF) reservoir needs to be implanted.

52.4.1 Critical Structures

• None

52.5 Soft Tissue Dissection

• Galea capitis and periosteum

◦ The galea capitis and periosteum are cut according to the shape of the skin incision.

52.5.1 Critical Structures

• None

52.6 Craniotomy/Craniectomy (See Chapter 50)

• Single burr hole

◦ Burr hole is usually 10 mm wide.

◦ It is placed 5 to 7 cm away from the midline, on the side of the dilated ventricle, just anterior to the coronal suture according to the procedure:

– Pure septostomy: Hole is placed 5-7 cm paramedian in order to achieve the more perpendicular route to the septum pellucidum.

– Septostomy and endoscopic tumor procedures (biopsy or endoscopic excision) in the area of the foramina of Monro: burr hole is placed 5 cm paramedian.

– Septostomy and endoscopic third ventriculostomy: Hole is performed 4 cm away from the midline.

52.6.1 Critical Structures

• None

52.7 Dural Opening

• Cross-shaped fashion

◦ A cortical exposure of 5-7 mm is needed to put the endoscope in place.

52.7.1 Critical Structures

• None

52.8 Intradural Procedure

• Intradural procedure comprises the following steps:

◦ Leptomeningeal and cortex bipolar coagulation and incision.

◦ Ventricle tap with a standard catheter to verify accuracy of the planned trajectory and to sample CSF when needed for laboratory testing.

◦ Peel away or endoscopic sheath freehand positioning (with a dynamic reference frame on it, if neuro-navigation tools are used) and fixation on a pneumatic/mechanic holder covered by a sterile drape (see Chapter 27).

◦ Endoscope placement through the sheath.

◦ Inspection of the ventricular cavity and identification of the local anatomy and landmarks (Fig. 52.2).

◦ Pulsated manual irrigation with lactate Ringer’s solution 36-37°C (always check that there is always one irrigation port unlocked to prevent dangerous spikes of intracranial pressure).