Peer-Review Reports

Intraventricular Tumors

Henry W. S. Schroeder

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INTRODUCTION

Intraventricular tumors are ideal indica-tions for neuroendoscopic surgery. Theselesions can easily be approached with theendoscope through the ventricular system.Moreover, because intraventricular tumorsoften cause cerebrospinal fluid (CSF) path-way obstruction, resulting in ventricular di-lation, sufficient space for maneuveringwith the endoscopes is available. However,even in patients with narrow ventricles, thelesions may be approached accurately andsafely with the aid of neuronavigation (16,17). The aims of endoscopy in intraventric-ular tumors are usually the restoration ofCSF pathway obstruction, clarification ofthe histology, and if possible, a completetumor removal (6).

Advantages of the endoscopic approachcompared with microsurgical resection arean improved visualization and illuminationin the depth of the ventricles as well as lessbrain tissue dissection and retraction.Craniotomies can be avoided because endo-scopes are inserted through simple burr

Key words� Endoscopic tumor removal� Intraventricular tumor� Neuroendoscopy� Occlusive hydrocephalus

Abbreviations and AcronymsCSF: Cerebrospinal fluidETV: Endoscopic third ventriculostomyMR: Magnetic resonance

Department of Neurosurgery, Ernst MoritzArndt University, Greifswald, Germany

To whom correspondence should be addressed:Henry W. S. Schroeder, M.D., Ph.D.[E-mail: Henry.Schroeder@uni-greifswald.de]

Citation: World Neurosurg. (2013) 79, 2S:S17.e15-S17.e19.http://dx.doi.org/10.1016/j.wneu.2012.02.023

Supplementary digital content available online.

Journal homepage: www.WORLDNEUROSURGERY.org

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1878-8750/$ - see front matter © 2013 Elsevier Inc.All rights reserved.

holes. Working through an operative t

WORLD NEUROSURGERY 79 [2S]: S17.e1

heath protects the surrounding structuresuch as fornix, hypothalamus, and vessels.nitially, endoscopic tumor surgery wasimited to tumor biopsy, mostly performedfter an endoscopic third ventriculostomyn patients presenting with tumor-relatedbstructive hydrocephalus (4, 13). As thexperience had grown, partial tumor resec-ions were performed. And finally, it be-ame possible to remove selected tumorsompletely with a pure endoscopic tech-ique (7).

NDICATIONS

ll intraventricular lesions that do not ex-eed a certain size limit are candidates forn endoscopic approach. However, it is dif-cult to determine the exact size limit of a

� OBJECTIVE: To describe the neuroventricular tumors.

� METHODS: Details of the endoscophe lateral, third, and fourth ventricle

RESULTS: Intraventricular tumors asurgery. They often cause cerebrospining in ventricular dilation, which provithe endoscope. The general principleular tumors is interruption of the blooddebulking. In general, a piecemeal retumors, it is possible to detach the lesremove it in toto. In unilateral hydroforamen of Monro, the burr hole is plathe foramen for biopsy and to the septin the anterior part of the third ventrisuture. When the tumor is located in thmore anteriorly in order to pass the forregion tumors, which cause occlusivpression, third ventriculostomy as we

� CONCLUSION: Intraventricular tumcan be safely and effectively treated wmay be totally removed via a ventricu

umor for an effective endoscopic resection. e

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he endoscopic piecemeal removal may be-ome time consuming and ineffective if theumor is too large. The benefit of the mini-

ally invasive approach is then outweighedy the duration of the operation. A solid

umor should not exceed 2 cm in diameter.ystic lesions may effectively be treatedven if they are larger. Tumor consistencynd vasculature are additional consider-tions. Extirpation of soft lesions is easiernd more rapid than the removal of firmnes. The ideal indication for an endo-copic treatment is a small and avascularumor located in the lateral or third ventri-le, in particular, if the lesion causes CSFathway obstruction, resulting in enlarge-ent of the ventricles. With the aid of bipo-

ar diathermy, even highly vascularized tu-ors such as cavernomas can be removed

scopic technique to deal with intra-

pproach to intraventricular tumors ofpresented.

eal indications for neuroendoscopicuid (CSF) pathway obstruction, result-sufficient space for maneuvering withe endoscopic removal of intraventric-ply to the tumor and subsequent tumortion is performed; however, in somefrom the surrounding brain tissue andhalus caused by obstruction of onemore laterally to get good access to

or septostomy. When the tumor arisesthe burr hole is made at the coronalsterior part, the entry point is selectedn of Monro in a straight line. In pinealdrocephalus due to aqueductal com-tumor biopsy are required.

nd related CSF pathway obstructionsendoscopic techniques. Small tumorsope.

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PEER-REVIEW REPORTS

HENRY W. S. SCHROEDER INTRAVENTRICULAR TUMORS

panying hydrocephalus, in which an endo-scopic resection is not feasible, are indica-tions for ventriculostomy, septostomy, oraqueductal stenting to restore CSF circula-tion. Tumor tissue sampling can be carriedout on any tumor that is visible at the ven-tricular surface. The use of a second work-ing portal enabling the insertion of larger

Figure 1. An ideal example for a total endoscoptranscortical endoscopic approach to the lesionmore complex, more invasive, and more risky.recurrent neurocytoma depicted on routine follmicrosurgical tumor resection 4 years earlier. (Aslightly contrast-enhancing lesion attached to thplanning. (D–H) Endoscopic views of the tumorCoagulation of the septum close to the tumorRemoval of the tumor with a grasping forceps.weighted coronal and axial MR image obtainedpatient is doing well without neurologic deficits

instruments and thus accelerating tumor m

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emoval has been advocated (10). We do notoutinely recommend two portals, becauset makes the approach more invasive andhe handling more difficult. If an endo-copic tumor removal turns out to be inef-ective, we do not hesitate to change to anpen microsurgical operation. With a smalleyhole approach and endoscope-assisted

oval of a tumor located at the septum pellucidumid and straightforward. Any microsurgical approacatient was a 41-year-old woman who presented wmagnetic resonance (MR) imaging after transcall1-weighted coronal and axial MR image showingtum pellucidum. (C) Neuronavigational approach

ction. (D) Tumor attached to the septum pellucidu. (F) Cutting of the septum around the tumor. (G

ree margins of the septum after tumor removal. (Irs after surgery showing complete tumor remova

icrosurgical techniques, an effective and i

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inimally invasive tumor removal withoutxtensive brain dissection as proposed byerneczky et al. is feasible (3, 14). Recently,n endoscopic technique has been de-cribed to remove intraventricular lesionssing a transparent tube or conduit to ap-roach the ventricle (8, 9, 11). In this endo-cope-controlled technique, the endoscope

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PEER-REVIEW REPORTS

HENRY W. S. SCHROEDER INTRAVENTRICULAR TUMORS

gical instruments are used along the endo-scope. Because there are no movement lim-itations of the instruments due to workingchannels, the dexterity of the dissection isimproved. However, the difference to a mi-crosurgical procedure is negligible. There-fore, when the endoscopic technique with aventriculoscope does fail or is not indicated,I still prefer an endoscope-assisted micro-surgical keyhole approach to deal withlarger intraventricular lesions.

ENDOSCOPIC TECHNIQUE

To deal with intraventricular tumors, a so-phisticated and complex neuroendoscopicsystem is required. It is important to have alarge working channel and effective instru-ments to be able to remove an intraventric-ular lesion completely. With small graspingforceps and a narrow working channel, ef-fective tissue removal is hard to achieve. Forhemostasis, a bipolar diathermy probe orforceps is required. Lasers can be used al-ternatively. However, the laser equipment is

Figure 2. An example of simultaneous endoscopi(ETV) and tumor biopsy performed via a single btumor (neurocytoma). The patient was a 49-yearwith headache, nausea, and vomiting. (A) T1-weresonance (MR) image showing a large contrastin the posterior third ventricle. (B–F) EndoscopicMonro. A trajectory was selected to approach thventricle and the tumor. (C) Floor of the third vebodies. (D) Third ventriculostomy with balloon c

much more expensive. Because hemor- m

WORLD NEUROSURGERY 79 [2S]: S17.e1

hage is frequent in endoscopic tumor re-ections, a continuous irrigation is neces-ary to maintain a clear view. An electricow- and pressure-controlled pump is

deal. For short periods of forced irrigation,syringe can be used. Lactated Ringer’s so-

ution at 36°C–37°C is preferable, becauseostoperative increases in body tempera-

ure, often seen after abundant irrigationith saline, are rarely encountered. To

void dangerous ICP increase, care must beaken to maintain a sufficient outflow ofrrigation fluid. It is ill advised to remove thecope in the case of bleeding. It is best totay in place, rinse, and wait. Larger vesselshat are at risk of being injured during tu-

or dissection should be cauterized withipolar diathermy before bleeding occurs.

n rare cases of severe hemorrhage, aspira-ion of CSF is needed to obtain a dry field.

ith this “dry field” technique, bleedingessels are more easily identified and hemo-tasis is quickly achieved.

The general principle of the endoscopicreatment of intra- and paraventricular tu-

ventriculostomyle in a third ventriclean who presentedsagittal magnetic

ncing lesion locateds. (B) Foramen ofr of the thirdwith mamillary

r. (E) Basilar artery

seen through the ventventricle. (G) Inversionobtained 3 days after sventriculostomy. The scompletely resolved afMR image obtained 2supracerebellar approadoing well without neu

ors is interruption of the blood supply to n

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he tumor and subsequent tumor debulk-ng. In general, a piecemeal resection is per-ormed; however, in some tumors, it isossible to detach the lesion from the sur-ounding brain tissue and remove it in toto.fter resection, a careful hemostasis is cru-ial in order to avoid rebleeding.

Generally, the entry point is selected ac-ording to information obtained by preopera-ive assessment of magnetic resonance im-ges or with the aid of neuronavigation (2, 5).he burr hole should be at the highest point tovoid excessive egress of CSF. Neuronaviga-ion is especially advisable in patients withmall ventricles or narrow foramina ofonro. If an asymmetric ventricular enlarge-ent or width of the foramen of Monro is

resent, the approach should be made via thearger ventricle or foramen of Monro. If feasi-le, the entry point should be located opposite

o the dominant hemisphere. Once a 3-cmtraight scalp incision has been made, a0-mm burr hole is placed. After opening theura, the operating sheath containing the tro-ar is introduced free-hand with or without

tomy. (F) Tumor in the posterior thirdery turbo spin echo sagittal MR imagey showing a strong flow void sign through theoms of increased intracranial pressureV. (H) T1-weighted contrast-enhanced sagittalafter tumor resection via an infratentorial-owing the total tumor resection. The patient isic deficits.

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PEER-REVIEW REPORTS

HENRY W. S. SCHROEDER INTRAVENTRICULAR TUMORS

cle and fixed with a self-retaining holding de-vice. Thereafter, the trocar is removed and theendoscope is inserted. After inspection of theventricle and identification of the main land-marks, that is, choroid plexus, fornix, andveins, the tumor is visualized.Capsule vessels are coagulatedwith the aid of a bipolar dia-thermy probe or forceps. Tu-mor specimens are taken forhistologic investigation. De-pending on the size of the le-sion, tumor resection usually begins with int-racapsular debulking or dissection in theplane between tumor and brain tissue. Feed-ing arteries should be identified early and cau-terized before bleeding blurs the view. Afterdissection of the tumor from the surroundingbrain, the lesion is removed in a piecemealfashion with the aid of various grasping andbiopsy forceps. The large operating sheath ofour equipment enables removal of solid tu-mor pieces of 6.5 mm in diameter and evenlarger pieces of soft tumors.

After tumor removal, the resection site isinspected to check that there is no activehemorrhage. The ventricles are vigorouslyirrigated to remove any clots. Then the op-erating sheath is withdrawn simultaneouslywith the endoscope to look for potentialbleeding at the foramen of Monro or in thecortical puncture channel. Usually, no ex-ternal ventricular drainage is placed. Wepack the burr hole with a gelatin sponge andtightly suture the galea to prevent subgalealCSF accumulation and fistula formation.The skin is closed with running atraumaticsuture. In general, the patient is observedovernight at the intermediate care unit.

TUMORS OF THE LATERAL VENTRICLE

The patient is placed supine with the headtilted slightly forward. For lesions of thefrontal horn and ventricular body, a stan-dard precoronal burr hole is made. Tumorsof the trigone are approached via a burr holethat is more anteriorly located in order toreach the target in a straight line throughthe ventricular body. In unilateral hydro-cephalus caused by obstruction of one fora-men of Monro, the burr hole is placed morelaterally to get good access to the foramenfor biopsy and to the septum for septos-tomy. Once the endoscopic sheath has beeninserted into the lateral ventricle, the tumor

VideoWORLDNEU

is visualized (Figure 1). At first, the relation f

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f the tumor to the choroid plexus ishecked before starting the tumor dissec-ion. The choroid plexus attached to the le-ion should be coagulated first. Usually, theoramen of Monro is patent after the tumor

resection. When the foramenis still occluded, CSF circula-tion can be restored by per-forming a septostomythrough the septum pelluci-dum. The septostomy is cre-ated by circular coagulation of

he septum in a thin and avascular area. Theissue bridges between the coagulationoints are cut with scissors except the lastedicle of the flap. This last pedicle israsped with a grasping or biopsy forcepsnd the whole septal flap is removed. Theize of the septostomy should be approxi-ately 8 mm2.

UMORS OF THE THIRD VENTRICLE

he patient is placed in supine positionith the head slightly flexed. When the tu-or arises in the anterior part of the third

entricle, the burr hole is made at the coro-al suture. When the tumor is located in theosterior part, the entry point is selectedore anteriorly in order to pass the fora-en of Monro in a straight line. Neuronavi-

ation can aid in determining the ideal entryoint and the approach trajectory through

he foramen of Monro. Tumors of the thirdentricle are resected according to the rulesescribed above.

In pineal region tumors that cause occlu-ive hydrocephalus due to aqueductal com-ression, third ventriculostomy as well as

umor biopsy are required (Figure 2). Whenhe foramen of Monro is of adequate size,oth procedures can be done via one burrole that is located about 2-3 cm in front of

he coronal suture. However, care has to beaken when the endoscope is tilted back-ards to the pineal tumor to avoid injury of

he fornix and the adjacent veins. When theoramen is small, tilting must not be done.hen a flexible scope is needed or two burroles have to be made— one at the coronaluture for the endoscopic third ventriculos-omy and one 4-5 cm anteriorly to reach theineal area in a straight line through the

oramen of Monro. Another option to re-tore CSF circulation is the placement of atent inserted through the aqueduct into the

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ourth ventricle. Then only one burr hole is

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equired even when the foramen of Monros narrow. To prevent stent migration, thetent should be connected to a burr holeeservoir. The best option to restore CSFirculation, however, is a total tumor re-oval. Unfortunately, most tumors are too

arge to be resected completely through thendoscope.

UMORS OF THE FOURTH VENTRICLE

umors of the fourth ventricle are usuallyetter approached microsurgically becausef the limited size of the fourth ventricle.ranscerebellar puncture of the fourth ven-

ricle has the risk of injuring the dentateucleus. However, because tumors of the

ourth ventricle often cause obstructive hy-rocephalus, a third ventriculostomy issually indicated. In selected cases, biop-ies can be taken through the aqueduct.

OMPLICATIONS

evere complications resulting in mortalitynd permanent morbidity are fortunatelyery rare (0%–3% in most reports in theiterature). Intraoperative hemorrhage ishe most frequently reported complication.ther complications include memory defi-

its, subdural hematomas, CSF leaks, andeningitis (1, 6, 12, 15).

ONCLUSION

ntraventricular tumors and related CSFathway obstructions can be safely and ef-

ectively treated with endoscopic tech-iques. Small tumors may be totally re-oved via a ventriculoscope. In larger

umors, endoscope-assisted microsurgeryr endoscopic resection via a larger conduitendoscope-controlled technique) is pref-rable to avoid a time-consuming resection.

REFERENCES

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3. Fries G, Perneczky A: Endoscope-assisted brain sur-

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HENRY W. S. SCHROEDER INTRAVENTRICULAR TUMORS

4. Fukushima T: Endoscopic biopsy of intraventriculartumors with the use of a ventriculofiberscope. Neu-rosurgery 2:110-113, 1978.

5. Gaab MR, Schroeder HWS: Endoscopic approach tolesions of the foramen of Monro [abstract]. Zen-tralbl Neurochir Suppl 56:42, 1995.

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8. Harris AE, Hadjipanayis CG, Lunsford LD, LunsfordAK, Kassam AB: Microsurgical removal of intraven-tricular lesions using endoscopic visualization andstereotactic guidance. Neurosurgery 56:125-132,2005.

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stereotactic guidance. Neurosurgery 62(Suppl2):622-629, 2008.

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1. Jho HD, Alfieri A: Endoscopic removal of third ven-tricular tumors: a technical note. Minim InvasiveNeurosurg 45:114-119, 2002.

2. Oi S, Shibata M, Tominaga J, Honda Y, Shinoda M,Takei F, Tsugane R, Matsuzawa K, Sato O: Efficacyof neuroendoscopic procedures in minimally inva-sive preferential management of pineal region tu-mors: a prospective study. J Neurosurg 93:245-253,2000.

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1A

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5. Schroeder HW, Oertel J, Gaab MR: Incidence ofcomplications in neuroendoscopic surgery. ChildsNerv Syst 20:878-883, 2004.

6. Schroeder HWS, Wagner W, Tschiltschke W, GaabMR: Frameless neuronavigation in intracranial en-doscopic neurosurgery. J Neurosurg 94:72-79,2001.

7. Souweidane MM: Endoscopic surgery for intraven-tricular brain tumors in patients without hydroceph-alus. Neurosurgery 57:312-318, 2005.

onflict of interest statement: Henry W. S. Schroeder is aonsultant to Karl Storz GmbH & Co. KG (Tuttlingen,ermany).

eceived 18 August 2011; accepted 02 February 2012

itation: World Neurosurg. (2013) 79, 2S:S17.e15-S17.e19.ttp://dx.doi.org/10.1016/j.wneu.2012.02.023

ournal homepage: www.WORLDNEUROSURGERY.org

vailable online: www.sciencedirect.com

878-8750/$ - see front matter © 2013 Elsevier Inc.ll rights reserved.

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