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|LETTERS TO EDITOR
|Year : 2019 | Volume
| Issue : 1 | Page : 305-306
Tapping the temporal horn – An alternative to Paine's point for intraoperative ventricular puncture
Girish Menon, Ajay Hegde
Department of Neurosurgery, Kasturba Medical College, Manipal, Karnataka, India
|Date of Web Publication||7-Mar-2019|
Dr. Ajay Hegde
Department of Neurosurgery, Kasturba Medical College, Manipal - 576 104, Karnataka
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Menon G, Hegde A. Tapping the temporal horn – An alternative to Paine's point for intraoperative ventricular puncture. Neurol India 2019;67:305-6
Adequate brain relaxation is necessary for the safe clipping of aneurysms of the circle of Willis. Acute aneurysm surgery is often complicated by the presence of severe cerebral edema and acute hydrocephalus. In spite of newer anesthetic techniques, optimal osmotic diuresis and appropriate positioning, adequate brain relaxation is often not attained. The angry red edematous brain prevents the release of cerebrospinal fluid (CSF) from the basal cisterns and the Sylvian fissure in such situations.
The accepted alternative in such cases is to tap the frontal horn through the Paine's point described in 1988. Paine's point is defined as “the intersection at right angles, of the lines measured 2.5 cm superior from the floor of the anterior cranial fossa (lateral orbital roof) and 2.5 cm anterior to the Sylvian fissure” [Figure 1]a. A ventriculostomy through this point reaches the frontal horn base. Although effective, the Paine's point trajectory lies close to the Broca's area on the left side and can at times result in injury to the caudate head, thalamus, and the basal ganglia. Even in experienced hands, tapping the frontal horn through the Paine's point can be challenging and Moon et al., have reported hemorrhage rates of 42.6%. An alternative to the Paine's point was proposed by Hyun et al., using a new landmark 2.5 cm superior to the lateral orbital roof and 4.5 cm anterior to the Sylvian fissure. This new landmark is more distant from the Broca's cortex than the point of Paine and provides a trajectory targeted between the caudate nucleus and the corpus callosum. Although comparatively safer, this technique too carries a risk of hemorrhage and injury to critical structures.
|Figure 1: (a) Representation of the Paine's point for ventricular access, and (b) the point in the middle temporal gyrus described by the authors to tap the temporal horn of the lateral ventricle|
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We propose a safer alternative through the temporal horn, which is technically easier and prone to lesser complication rates. The technique involves tapping the temporal horn through the middle temporal gyrus or the inferior part of the superior temporal gyrus. The temporal horn lies 3 cm from the tip of the temporal lobe [Figure 1]b. The pia is coagulated approximately 3 cm behind the temporal pole, and the cannula is directed inferiorly and perpendicular to the long axis of the temporal horn. A small corticectomy too may be done at times to reach the ventricle, which is often hit at a depth of 1–1.5 cm.
The first author has been regularly adopting this technique in acute aneurysm surgery for the last 5 years and has used this technique for nearly 30 cases when all other attempts for achieving brain relaxation failed. We always prefer to approach the ventricle through the middle temporal gyrus. This may require nibbling of the temporal bone and widening the dural opening a bit as the brain is tense and bulging, and the middle temporal gyrus is not be easily seen. In six cases, the corticectomy had to be widened by a few millimeters, and in four patients, a fresh entry had to be made behind the first one. Postoperative CT scan revealed a small temporal hematoma in one case, which was managed conservatively.
This technique should be avoided in the cases where the ventricles are small. This is decided on the preoperative computed tomography imaging. Though this procedure theoretically carries a risk of injury to the mesial temporal structures, this occurs only if the catheter is placed too deep, more than 2–2.5 cm from the cortex. Moreover, these structures will be encountered only after hitting the ventricle and further advancement of the catheter should be stopped at this stage.
Overall, we feel that this technique carries no risk of injury to any vital structures and provides adequate CSF drainage from the ventricle to facilitate exposure of the cisterns prior to performing the aneurysm surgery.
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Conflicts of interest
There are no conflicts of interest.
| » References|| |
Paine JT, Batjer HH, Samson D. Intraoperative ventricular puncture. Neurosurgery 1988;22:1107-9.
Hyun SJ, Suk JS, Kwon JT, Kim YB. Novel entry point for intraoperative ventricular puncture during the transsylvian approach. Acta Neurochir (Wien) 2007;149:1049-51.
Moon HH, Kim JH, Kang HI, Moon BG, Lee SJ, Kim JS. Brain injuries during intraoperative ventriculostomy in the aneurysmal subarachnoid hemorrhage patients. J Korean Neurosurg Soc 2009;46:215-20.