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|Year : 2012 | Volume
| Issue : 3 | Page : 269-270
Endoscopic management of trapped fourth ventricle using the posterior fossa route
Department of Neurological Sciences, Christian Medical College, Vellore, Tamilnadu, India
|Date of Submission||23-May-2012|
|Date of Decision||23-May-2012|
|Date of Acceptance||01-Jun-2012|
|Date of Web Publication||14-Jul-2012|
Department of Neurological Sciences, Christian Medical College, Vellore
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Rajshekhar V. Endoscopic management of trapped fourth ventricle using the posterior fossa route. Neurol India 2012;60:269-70
In this issue of the journal, Gallo et al. present a series of 18 patients with symptomatic trapped fourth ventricle (TFV), managed endoscopically, over a period of 17 years, using the posterior fossa route.
TFV is an uncommon problem as is evident from the fact that the authors managed only 18 patients over 17 years, roughly one patient a year. However, it is a difficult problem to deal with as the fourth ventricle shunts that are commonly used to treat this condition are prone to malpositioning during surgery and also frequently malfunction. Endoscopic techniques that came into vogue during the 1990s have been suggested as the ideal procedure for the management of this entity. Essentially, the main cause of a TFV, namely, the aqueductal obstruction, is addressed using an endoscopic technique, and hence it is the most rational of all surgeries for this condition. The aqueduct can be dilated and kept open using a stent either through a transfrontal (trans-third ventricle) route or through a trans-fourth ventricular route. The latter is a shorter route, but is less commonly used probably due to the lack of familiarity with the endoscopic anatomy of the region of the fourth ventricle.
With either route, the surgeon has to decide whether a simple dilatation of the aqueduct will suffice or to leave a stent in place. The advantage of a stent is that the patency of the aqueduct is ensured in the postoperative period unless the stent migrates. The major disadvantage is that of infection due to the presence of a foreign body. The authors placed a stent whenever the dilated aqueduct was narrower than the width of the stent. Although theoretically it is possible to produce additional neurological deficits by introducing a wider stent through a narrower aqueduct, in the authors' series, the complications (two patients with ophthalmoparesis) were equally distributed between those who had a stent placed and those who underwent aqueductoplasty alone. Hence, it appears that fear of additional deficits should not deter a surgeon from using a stent.
The authors also discuss the technical aspects of the patient's position during the surgery. There are advantages and disadvantages to both the sitting and prone positions during any posterior fossa surgery, but overall I endorse the authors' decision to recommend the prone position as it is generally safer for the patient. With appropriate measures, the inconvenience of CSF welling up in the field can be tackled to provide adequate visualization during the endoscopic procedure.
The authors are to be congratulated for clearly describing and illustrating their surgical technique. The durability of their results is documented with the long follow-up they had in their patients. I, for one, am convinced that their technique is probably best suited for the management of TFV and would recommend it to all surgeons who are familiar with neuro-endoscopic techniques. The only situation in which the authors' technique cannot probably be used is when a TFV is due to a post-infectious state such as tuberculous meningitis or cysticercosis. In these settings the subarachnoid space in the region of the cisterna magna will be inaccessible due to arachnoiditis and subsequent adhesions.
| » References|| |
|1.||Gallo P, Szathmari A, Simon E, Ricci-Franchi AC, Rousselle C, Hermier M, et al. The endoscopic trans-fourth ventricle aqueductoplasty and stent placement for the treatment of trapped fourth ventricle: Long-term results in a series of 18 consecutive patients. Neurol India 2012;60;271-7. |