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Table of Contents    
Year : 2020  |  Volume : 68  |  Issue : 1  |  Page : 159-162

Contralateral Ventriculostomy for Intraoperative Brain Relaxation in Supratentorial Brain Tumors

Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India

Date of Web Publication28-Feb-2020

Correspondence Address:
Dr. Shashwat Mishra
Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, 601, Neurosciences Centre, All India Institute of Medical Sciences, Ansari Nagar New Delhi
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0028-3886.279710

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 » Abstract 

Background: CSF drainage from the ventricular system is a popular and effective technique for intraoperative brain relaxation as it reduces ICP, enlarges extra-axial operative corridors, and slackens the brain increasing its tolerance for surgical manipulation. However, sometimes when the ventricular chambers distant from the site of pathology are tapped, there is a risk of neurological worsening due to paradoxical herniation of the brain, exemplified by the phenomenon of upward transtentorial herniation observed in posterior fossa tumors, consequent to a supratentorial ventriculostomy. Expectation of an analogous phenomenon precludes contralateral ventricular drainage in supratentorial brain tumors producing midline shift, subfalcine herniation, and resultant distension of the opposite lateral ventricles.
Objective: Demonstrating the safety and efficacy of intraoperative contralateral ventricular drainage in the presence of sub-falcine herniation.
Methods: Clinical and imaging information were retrospectively collected for four cases in which this technique was adopted.
Results: The first case was a large clinoidal meningioma with a midline shift and contralateral ventriculomegaly. EVD from the dilated ventricle provided optimum brain conditions for safe resection of the tumor through an orbitopterional approach. The second case required a contralateral EVD to reduce ICP intraoperatively, for a recurrent anaplastic ependymoma with severe mass effect. It reduced the venous hypertension related to raised ICP minimizing the blood loss. Contralateral EVD was utilized to enlarge the working corridor for interhemispheric approach in two cases.
Conclusion: Contralateral ventricular drainage is a safe, effective, and convenient operative step for reducing brain turgor in the presence of sub-falcine herniation produced by large supratentorial tumors.

Keywords: Contralateral, herniation, sub-falcine, supratentorial, ventriculostomy
Key Messages: Our initial experience with contralateral ventricular drainage shows that, even in the presence of subfalcine herniation, it is a useful strategy for ensuring brain relaxation as a preparatory measure when operating on large supratentorial tumours.

How to cite this article:
Gurjar HK, Mishra S, Garg K. Contralateral Ventriculostomy for Intraoperative Brain Relaxation in Supratentorial Brain Tumors. Neurol India 2020;68:159-62

How to cite this URL:
Gurjar HK, Mishra S, Garg K. Contralateral Ventriculostomy for Intraoperative Brain Relaxation in Supratentorial Brain Tumors. Neurol India [serial online] 2020 [cited 2020 Jul 5];68:159-62. Available from:

CSF drainage from the ventricular system is a popular strategy for achieving brain relaxation in the presence of hydrocephalus. A slack brain presents several advantages during brain tumor surgery and is especially indispensable for approach to extra-axial brain tumors. A symmetrically dilated ventricular system is conventionally considered a prerequisite for the safe execution of intraoperative ventricular drainage. However, it is frequently observed that large supratentorial tumors produce a sub-falcine herniation with contralateral ventricular dilatation and effaced ipsilateral ventricles. It is commonly believed that tapping the enlarged ventricular chamber in such a setting can worsen the herniation, leading to the patient's detriment. We describe a series of cases where we punctured the contralateral ventricle in such situations establishing the feasibility, safety, and efficacy of this maneuver for achieving a slack brain during surgery for supratentorial tumors.

Case 1

A 26-year-old gentleman presented with worsening bifrontal headaches and diminution of vision in the right eye which he had noticed over the past 3 months. MR imaging revealed a large clinoidal meningioma [Figure 1]a, [Figure 1]b, [Figure 1]c, [Figure 1]e with a chronic sub-falcine herniation of the brain producing an enlargement of the contralateral lateral ventricles. A ventricular drain was placed through the left Kocher's point (3 cm lateral to midline and 1 cm anterior to the coronal suture) and allowed to drain around 20 ml of clear CSF. A pterional craniotomy was fashioned on the right side and the orbital rim was removed. The slack dural compartment greatly facilitated the extradural anterior clinoidectomy which was necessary for devascularizing the tumor. The dura was then opened and, despite the tumor mass, a relaxed brain greeted the surgeon. The tumor was removed in totality [Figure 1]f and [Figure 1]g without any cortical insult due to the effective brain relaxation achieved through the ventricular CSF drainage.
Figure 1:(Case 1): Left panel (a-e) preoperative post-Gd images of a large clinoidal meningioma with chronic subfalcine brain herniation and contralateral ventricular dilatation. Right panel (f and g) postoperative axial post-Gd image showing complete tumor excision with minimal injury to brain parenchyma; (g) coronal postoperative T2 images showing a faint track for EVD (white arrowheads) placed in contralateral ventricle

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Case 2

A 12-year-old child had been operated for a left-sided temporal anaplastic ependymoma. After 24 months of the initial surgery, he presented in distress to the emergency room with a decline in consciousness and repeated vomiting [Figure 2]a and [Figure 2]b. Emergent CT imaging revealed a large recurrence at the operative site with severe perilesional edema causing a brain shift and distention of the lateral ventricles on the right side. Anticipating the vascularity of the tumor and the limited physiological capacity of a small child to tolerate exsanguination, strategies for minimization of intraoperative blood loss were considered. The contralateral ventricular puncture site was marked, before positioning the patient for craniotomy. Once the craniotomy flap was elevated, the dural compartment was observed to be extremely tense. Therefore, the ventricular drain was placed in the opposite ventricle before durotomy. We expected that this would lower the ICP and venous tension in conjunction, which would lead to reduced venous bleeding. Our reasoning was confirmed intraoperatively and the tumorectomy could be achieved with relative ease [Figure 2]c and [Figure 2]d with acceptable blood loss due to a conducive brain condition at the beginning of the operation.
Figure 2: Upper panel (Case 2) (a and b) Emergent plain CT head showing a large recurrence of anaplastic ependymoma on the left side with a large midline shift and right ventriculomegaly; (c and d) immediate postoperative CT images showing near total resection and burr-hole for EVD insertion (black arrow). Lower panel (Case 4) (e and f) small posterior third falcine meningioma with extensive perilesional edema midline shift; (g) postoperative axial T2 image showing complete excision and resolution of edema: (h) Postoperative SWI MR sequence showing the EVD track to the ventricle contralateral to lesion (white arrow)

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Case 3

A small falcine meningioma was detected in a middle-aged female who complained of severe headaches accompanied by visual obscurations of several weeks duration [Figure 2]e and [Figure 2]f. MRI imaging further revealed extensive edema in the surrounding brain parenchyma with dilatation of the contralateral ventricle, owing to midline shift and sub-falcine herniation. Since the tumor was in an eloquent location, cortical injury during interhemispheric approach to the tumor was anticipated. When the dura was found to be extremely turgid upon the parasagittal craniotomy, a contralateral ventricular drain was placed to achieve brain relaxation which protected the enveloping cortex during tumor removal [Figure 2]g and [Figure 2]h.

Case 4

An interhemispheric approach was planned for a high-grade glioma judged to be arising from the cingulate gyrus. To facilitate the exposure, a contralateral ventricular drain was placed and the overlying eloquent cortex was protected from adverse effects of physical handling. The intraoperative cryosection pathological diagnosis was strongly suggestive of lymphoma. Therefore, the lesion was only partially enucleated till the mass effect was relieved.

 » Discussion Top

The indispensability of a slack brain for ensuring optimum outcomes of surgeries on intracranial brain lesions has been implicitly recognized by neurosurgeons for long. It becomes especially important when planning extra-axial approaches to deep-seated brain lesions, where the surgeon exploits the space offered by the brain shrinking away from the dural structures. Several strategies have been commonly employed for accomplishing this permissive state of the brain. They include aspects of positioning where the head is kept elevated to facilitate venous drainage, administration of osmotic diuretics to reduce brain volume, and use of intravenous anesthetic agents.[1],[2] However, in patients with large tumors, extensive perilesional edema, and acute clinical presentation, the above methods may prove insufficient to produce an optimum brain condition.

CSF drainage has a dramatic effect on reducing brain turgor and volume. In the setting of traumatic brain injury, drainage of as little as 3 ml of CSF from the ventricles has been effective in reducing the ICP by more than 15%, although the effect is transient.[3] However, when CSF drainage is employed during craniotomy, it sets up a positive feedback cycle progressively drawing CSF from sites distant to the drainage point. This results in increased relaxation of the brain. The potential spaces from which CSF can be drained are the sulci, arachnoid cisterns, and the ventricle.

Opening of multiple sulcal spaces[4] on the surface of the exposed brain is a useful strategy for gradually shrinking a “full” brain, but is insufficient in the presence of hydrocephalus or severe mass effect. For intraoperative brain relaxation, LSD is much more efficacious. However, placement of the lumbar subarachnoid catheter is a procedure in itself as it adds to the operative time and requires dedicated positioning of the patient. Moreover, it is contraindicated in the presence of intracranial mass lesions for the fear of precipitating a tonsillar herniation. Even, in the absence of intracranial space occupying lesions, this can occur as a delayed complication after LSD, as encountered in about 10% cases.[5] “Sinking brain”[6] and “brain sag”[7] are the other troublesome phenomena observed with LSD.

Intraoperative ventricular puncture avoids the issues complicating LSD and has been frequently used when dealing with “angry brains” in the setting of subarachnoid hemorrhage. Paine et al.,[8] described a method for tapping the frontal horn through the frontolateral exposure, which has since been revised,[9] increasing its safety and accuracy. The temporal horn may also be similarly cannulated,[10] if the frontal horn is inaccessible. The popularity of these techniques attests to their practical utility when the surgeon is battling an uncooperative and turgid brain. However, when large supratentorial space-occupying lesions efface the lateral ventricle and cause significant shift of anatomical structures, reaching the ipsilateral ventricle becomes difficult and risky. In such situations, the contralateral ventricle presents a potential source for CSF drainage.

The primary apprehension in tapping the contralateral ventricle is a risk of worsening the sub-falcine herniation. It may appear justifiable in view of the observations regarding reverse cerebellar herniation seen with ventriculostomy in posterior fossa tumours and tonsillar herniation linked with LSD. However, important anatomical peculiarities distinguish sub-falcine herniation and those affecting the posterior fossa. The posterior fossa converges toward the tentorial hiatus and the foramen magnum. Therefore, it is likely for the brain parenchyma under pressure to plug these openings in the manner of a “bath plug” upon CSF drainage from distant sites. Even without a rise in ICP, chronic pressure gradients across these narrow hiatuses may precipitate unexpected herniations.[11],[12],[13] In contrast, the sub-falcine window is much wider and roomy and it is improbable to have a water tight seal between the hemispheric brain compartments, caused by herniation of brain tissue. Hence, aggravation of the midline brain shift by contralateral ventricular drainage is unlikely. It must be stressed that in all our cases, ventricular drainage was immediately followed by excision of the lesion and we are unsure of the long-term safety of prolonged contralateral ventriculostomy as a temporizing measure for reducing ICP.

Interestingly, Narotam et al.[14] recorded ICP bilaterally from patients who underwent contralateral ventricular drainage following persistently elevated ICP with midline shift. All these patients have undergone surgical evacuation of mass lesions. They observed that though there were initial intercompartmental differences in ICP recordings, with prolonged CSF drainage, a secular trend toward reduction in ICP was seen in both supratentorial hemispheres. This observation supports our hypothesis that the effect of CSF drainage from contralateral ventricle is not compartmentalized.

If needed emergently, during the course of the operation, freehand contralateral ventricular puncture may need to be performed in an anatomically awkward position. Hence, neuronavigation assistance is invaluable. In our cases, we did not use intraoperative navigation. Accordingly, we marked and rehearsed the trajectory for ventricular puncture before draping the head. We also employed table rotation and elevation to make ventricular targeting as anatomical as possible for the surgeon after positioning for the craniotomy. The amount of CSF to be drained from the ventricle depends upon the surgeon's impression of brain relaxation, but usually 20–30 ml was felt to be adequate in our cases.

 » Conclusion Top

Contralateral ventricular puncture, in the setting of sub-falcine herniation with ipsilateral ventricular effacement, is an effective, safe, and invaluable strategy for optimizing the brain condition during surgery for large lesions. Though our experience is small, it negates the commonly held apprehension that such operative maneuvers may worsen brain herniation.


CSF = cerebrospinal fluid, EVD = external ventricular drainage, LSD = lumbar spinal drainage, ICP = intracranial pressure.

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Conflicts of interest

There are no conflicts of interest.

 » References Top

Romani R, Silvasti-Lundell M, Laakso A, Tuominen H, Hernesniemi J, Niemi T. Slack brain in meningioma surgery through lateral supraorbital approach. Surg Neurol Int 2011;2:167.  Back to cited text no. 1
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Li J, Gelb AW, Flexman AM, Ji F, Meng L. Definition, evaluation, and management of brain relaxation during craniotomy. Br J Anaesth 2016;116:759-69.  Back to cited text no. 2
Kerr ME, Weber BB, Sereika SM, Wilberger J, Marion DW. Dose response to cerebrospinal fluid drainage on cerebral perfusion in traumatic brain-injured adults. Neurosurg Focus 2001;11:E1.  Back to cited text no. 3
Yaşargil MG, Abernathey CD. In: Microneurosurgery, Vol. IV B. Thieme; 1996. p. 57, 72.  Back to cited text no. 4
Motoyama Y, Nakajima T, Takamura Y, Nakazawa T, Wajima D, Takeshima Y, et al. Risk of brain herniation after craniotomy with lumbar spinal drainage: A propensity score analysis. J Neurosurg 2018;1-11. doi: 10.3171/2017.12.JNS172215.  Back to cited text no. 5
Kelley GR, Johnson PL. Sinking brain syndrome: Craniotomy can precipitate brainstem herniation in CSF hypovolemia. Neurology 2004;62:157.  Back to cited text no. 6
Komotar RJ, Mocco J, Ransom ER, Mack WJ, Zacharia BE, Wilson DA, et al. Herniation secondary to critical postcraniotomy cerebrospinal fluid hypovolemia. Neurosurgery 2005;57:286-92.  Back to cited text no. 7
Paine JT, Batjer HH, Samson D. Intraoperative ventricular puncture. Neurosurgery 1988;22:1107-9.  Back to cited text no. 8
Park J, Hamm I-S. Revision of Paine's technique for intraoperative ventricular puncture. Surg Neurol 2008;70:503-8.  Back to cited text no. 9
Menon G, Hegde A. Tapping the temporal horn-An alternative to Paine's point for intraoperative ventricular puncture. Neurol India 2019;67:305-6.  Back to cited text no. 10
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Novak L, Pataki I, Nagy A, Berenyi E. Bilateral transtentorial herniation and isolated fourth ventricle: A scientific note. Neurol India 2010;58:953-4.  Back to cited text no. 11
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Udayakumaran S, Ben Sira L, Constantini S. Chronic uncal herniation secondary to posterior fossa shunting: Case report and literature review. Childs Nerv Syst 2010;26:267-71.  Back to cited text no. 12
Udayakumaran S. Bilateral transtentorial herniation and isolated fourth ventricle: A scientific note. Neurol India 2011;59:322.  Back to cited text no. 13
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Narotam PK, van Dellen JR, Gouws E. The role of contralateral ventricular dilatation following surgery for intracranial mass lesions. Br J Neurosurg 1993;7:281-6.  Back to cited text no. 14


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