Peer-Review Short Reports

Endoscopic Supracerebellar Infratentorial Retropineal Approach for Tumor Resection

Kuan-Yin Tseng, Hsin-I Ma, Wei-Hsiu Liu, Chi-Tun Tang

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INTRODUCTION

Pineal region tumors include those arisingfrom the pineal gland and as well as othersinvolving the posterior third ventricle andquadrigeminal cistern. Primary pineal-ori-gin tumors (POTs) are uncommon, com-prising 0.4%-0.5% of intracranial lesions,with incidences that vary geographically (9,15). Until recently, the results of surgery forPOT, including mortality and morbidity,have been poor (19). Several surgical strate-gies have been described for the treatmentof POT, including the supracerebellar in-fratentorial (3, 12) and occipital transtento-rial microsurgical approaches (20), the trans-ventricular endoscopic approach (6, 7, 17),and stereotactic aspiration (14). We report thefirst patient whose pineal tumor was entirelyexcised endoscopically via the supracerebellarinfratentorial (S-C) approach.

CASE REPORT

History and Neurological ExaminationsA 21-year-old man presented with diplopiaand blurred vision during the period of 2

Key words� Endoscopy� Pineal tumor� Supracerebellar infratentorial approach

Abbreviations and AcronymsGCT: Germ-cell tumorMRI: Magnetic resonance imagingPOT: Pineal origin tumorS-C: Supracerebellar infratentoria

Department of Neurological Surgery, Tri-serviceGeneral Hospital, Taipei, Taiwan

To whom correspondence should be addressed:Chi-Tun Tang, M.D. [E-mail: neuronsugery@yahoo.com.tw]

Citation: World Neurosurg. (2012) 77, 2:399.e1-399.e4.DOI: 10.1016/j.wneu.2011.05.035

Supplementary digital content available online.

Journal homepage: www.WORLDNEUROSURGERY.org

Available online: www.sciencedirect.com

1878-8750/$ - see front matter Crown Copyright © 2012Published by Elsevier Inc. All rights reserved.

months. Initially, he consulted a local oph- m

WORLD NEUROSURGERY 77 [2]: 399.e1-

halmologist, who diagnosed him as havingsuperior rectus muscle palsy. However,

he patient’s symptoms worsened 1 weekefore admission. Then, he was referred tour department for surgical assessment.eurological examination revealed limita-

ion of upward gaze and convergent nystag-us on attempted up-gaze (i.e., Parinaud

ign). The patient had normal mental devel-pment and was sexually mature.

Magnetic resonance imaging (MRI)emonstrated a heterogeneous enhancing

esion approximately 1.2 � 2.5 cm in sizehat was located mainly in the pineal region.he tumor had directly invaded the dorsal-

� BACKGROUND: Lesions located inchallenge. Multiple approaches to thisadvantages and disadvantages. We repsupracerebellar infratentorial approacUnlike transventricular endoscopy, thiand can be applied independent of ve

� CASE DESCRIPTION: A 21-year-oldnetic resonance images of brain reveamass that originated from the pineal glthe tectum and invaded to the bilateralbut caused no obstructive hydrocephalcerebrospinal fluid, alpha-fetoprotein,were negative. The patient was referr

� TECHNIQUE: The patient was possupracerebellar infratentoria corridorburr holes, which provided natural byillumination and magnification withocould be achieved with the aid of the ecompletely via the full-endoscopicdiplopia resolved completely, and his

� CONCLUSIONS: Taking the advantpracerebellar infratentoria corridor, wtotal tumor without violating the criticaapproach can be performed regardlessit is an excellent minimally invasive supineal tumor.

edial thalamus. Moreover, the tumor ex- d

399.e4, FEBRUARY 2012 www.WO

rted mass effect on the superior colliculi,paring the aqueduct (Figure 1). No ob-tructive hydrocephalus was present. Thereere no synchronous lesions in the brain or

pine. The imaging findings were consis-ent with a primary POT. The findings of theerebrospinal fluid examination were nor-al, with no atypical cells noted. Serum and

erebrospinal fluid, beta-human chorioniconadotropin, and alpha-fetoprotein weressayed as tumor markers and found to beithin normal values. According to the re-

ults, an intracranial germ-cell tumorGCT) was highly suspected. We discussedhe therapeutic modality of diagnostic ra-

pineal region represent a surgicalon have been described, each with itsthe first application of the endoscopiccomplete resection of a pineal tumor.hnique poses no risk to the fornicesular size.

sought treatment for diplopia. Mag-a heterogeneous, contrast-enhancingThis tumor exerted the mass effect ono-medial thalamus and hypothalamushe results of a cytological study of the

beta-human chorionic gonadotropinor the surgical work-up.

ed in the semi-sitting position. Thes accessed through two paramedianity cerebellar traction. The excellentcrificing the inferior occipital sinus

scope. The pineal tumor was resectedoach. Postoperatively, the patient’sital course was uneventful.

of the endoscope and peculiar su-ould successfully remove the gross-urovascular structures. Moreover, thishe size of the ventricle. Consequently,al option for resection of symptomatic

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PEER-REVIEW SHORT REPORTS

KUAN-YIN TSENG ET AL. ENDOSCOPIC S-C RETROPINEAL APPROACH

cal verification. The patient chose surgicaltreatment and attempted resection.

Operative TechniqueThe patient underwent preoperative con-trast MRI examination of the brain to obtainthin-cut volumetric images. These imagesdata were transferred to the VectorVisionflex (BrainLab, Feldkirchen, Germany) tointegrate them into the intraoperative navi-gation system. The patient was placed in thesemi-sitting position, and we took appro-priate precautions for balanced general an-esthesia. Transesophageal echocardiogra-phy and a right internal jugular venouscatheter were applied for the detection andtreatment of air embolism during surgery.The vector-reference system was used to lo-calize the torcular herophili. Two 25-mmburr holes were made just beneath to thetransverse sinus inferior wall approxi-mately 25 mm distal to the midline (Figure2). The paramedial location was selected toavoid the occipital sinus. Moreover, the bi-lateral burr holes provided a wide, cooper-ative working space. One hole was for en-doscopic illumination and the other forintroducing instrumentation. The durawas incised in cruciate fashion. A 18-cmlong, rigid 0-degree endoscope tube withan outer diameter of 4 mm, a built-in suc-tion irrigation system, and an inlet forvarious microinstruments (Karl Storze,Tuttlingen, Germany), enclosed withinthe sheath, was introduced into left burr

Figure 1. Magnetic resonaimaging of the sagittal (Aaxial (B) planes show aheterogeneous enhancinglesion approximately 1.2size in the pineal region tdirectly invades the bilatedorso-medial thalami.

hole.

399.e2 www.SCIENCEDIRECT.com

After fixing the endoscope to the scopeolder with a flexible arm, we introduced

he dissectors and curettes, into the otherurr hole under endoscopic visualization.e adopted the retrograde lysis of the fi-

rous band and then opened the arachnoi-al trabeculae of the posterior wall of theilateral ambient cisternsnder the bilateral petrouspices. The sequential open-ng of the torcular herophilind bilateral ambient cis-erns leads to more relax-tion of the cerebellum. Thehick arachnoidal band tethering the supe-ior vermis and culmen were dissectedharply to expose the precentral cerebellarein. We switched the position of endo-cope through both holes when we encoun-

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Figure 2. Intraoperative photography showingthe two 25-mm burr holes placed justbeneath to the transverse sinus inferior wall,approximately 25 mm distal to the midline

n(coronal view).

WORLD NEUROSURGE

ered fibrous bands or arachnoidal trabecu-ae. We carefully coagulated the vein andissected using endo-scissors (Karltorze).

The pineal tumor was gray in color with aelatively soft texture. It was located slightly tohe left side, tightly juxtaposed between theeft pulvinar thalami and posterior medialhoroidal artery. After identifying the pineal

vein and feeding arteries, we dis-sected the wall of tumor and cau-terized the blood supplies. Piece-meal central debarking wasperformed by the use of pituitarycurettes (Aesculap, Boston, Mas-

achusetts, USA; Figure 3). After gross de-ompression, we removed the residual wallith Kerrison forceps. We excised the tumorntil we reached the posterior third ventricle

hrough the para-pineal region, a small entryone approximately 3 mm lateral to pinealland, underneath the internal cerebral veinnd parallel to the upper margin of the supe-ior colliculi. The tumor over dorsal-medialhalamus was grasped without incident. Af-er gross total resection, the anatomy of theosterior incisural space was clearly seennder the 0-degree endoscope (Karl Storze)nd after another check with a 30-degreendoscope (Karl Storze). The durotomiesere closed with silk sutures and then cov-

red by Gelfoam sheets (Upjohn Co., Kala-azoo, MI). A layer of tissue fibrin sealant

Confluent Surgical, Waltham, MA) wasprayed over the dura. The remainder of thelosure was accomplished in the standarday.Postoperatively,thepatienthadnonew-onset

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Figure 3. Intraoperative photography showingthe pineal tumor was debarked centrally bythe pituitary curettes. The pineal origin tumor(POT), tentorrium (T), pulvinar nuclus (P), andcerebellar culmen (C), and the posterior thirdventricle (V) are visible.

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PEER-REVIEW SHORT REPORTS

KUAN-YIN TSENG ET AL. ENDOSCOPIC S-C RETROPINEAL APPROACH

formed within 24 hours after the operation,whichconfirmedthecompleteresection(Figure4).PathologyrevealedapictureofmixedGCTofgerminoma with teratoma. The adjuvant radia-

Figure 4. Postoperative sagittal T1-weighted MRsagittal (A) and axial (B) planes demonstratingthe tumor.

Figure 5. The diagram demonstratesshape looked like a quadrilateral fruspetrous part of temporal bone. The rThe floor of quadrilateral frustum is csuboccipital bone. The apex is the pithe quadri-geminal cistern. Cm, culmcerebral vein; MPC, medial posteriortentorium cerebelli; TS, transverse sibone; SS, sigmoid sinus; SV, superio

Rosenthal.

WORLD NEUROSURGERY 77 [2]: 399.e1-

ion therapy of 45 Gy was increased 2 weeksater. At his 6-month and 12-month postopera-ive visits, the patient’s the diplopia resolved,nd he was not taking any pain medication.

ns after gadolinium administration of theperative changes and confirming removal of

orridor” had six faces and the grosshe bilateral faces are composed ofcomposed of tentorium cerebella.llar culmen. The broad bottom island and the plane of the opening to, cerebellar hemisphere; ICV, internal

idal artery; PG, pineal gland; TC,H, torcula herophill; SO, suboccipitalis; VG, vein of Galen; VR, vein of

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399.e4, FEBRUARY 2012 www.WO

ISCUSSION

OTs, an uncommon but intriguing group ofeoplasms affecting children and youngdults, have been systematically classified byistology (15). Resection is superior to other

reatment modalities for POT that are benignr radioresistant (16). Malignant tumors maylso be amenable to resection or may containcyst requiring removal or aspiration (5). Forerminoma in the pineal region, treatmenttrategies vary; some authors currently preferirect surgical removal, whereas others advo-ate stereotactic biopsy followed by radiother-py or chemotherapy (11, 18). In addition toure germinoma, there are germinomas withyncytiotrophoblastic giant cells and mixedCTs, including germinoma. The primaryoal of surgery should be to obtain a sufficientolume of tumor tissue for histological exam-nation. Many types of POTs are not sensitiveo radiation, and the radical removal of theman often improve the overall response toreatment, including adjuvant radiotherapy orhemotherapy (15).

However, posterior approaches to the pi-eal region and the posterior portion of the

hird ventricle are difficult to execute, givenhe complexity and importance of the vitaleurovascular structures that are tightlyacked in these areas (1, 2). As discussed bytein (13), the infratentorial-supracerebel-

ar approach allows adequate exposure ofesions positioned in the midline.

In the past two decades, neuroendoscopyas come to the forefront for the manage-ent of complex hydrocephalus and intracra-

ial cysts. In a cadaver-based anatomic study,ardia et al. (2) and Youssef et al. (21) demon-trated the viability of the S-C approach forndoscope-assisted techniques. In our ownbservation, the S-C gap unveiled a corridor

nto which we fit the endoscope and pistol-yped instruments. This space, known forS-C corridor,” has six faces and the grosshape of a quadrilateral frustum. The lateralaces were composed of one tentorium cer-belli, one cerebellar culmen, and two petrousone aspects. The broader bottom of the boneomprised the suboccipital bones. The apexf the frustum was the plane of the opening to

he quadri-geminal cistern (Figure 5). On ac-ount of its unique position related to the pi-eal region, we defined this space as theretro-pineal frustum” space.

In the middle of the space was the fibrousand, into which was embedded some bridg-

I scaposto

S-C ctum. Toof iserebeneal gen; CHchoronus; Tr verm

ng veins and thickened arachnoidal trabecu-

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PEER-REVIEW SHORT REPORTS

KUAN-YIN TSENG ET AL. ENDOSCOPIC S-C RETROPINEAL APPROACH

lae. We adopted the retrograde neurolysis ofthe fibrous band then opened the arachnoidtrabeculae of the posterior wall of the bilateralambient cisterns under the bilateral petrousapices. This sharp “figure-of-eight” discon-nection separated the anterior traction forcebetween the tentorium and cerebellum. Themajor force adhering the cerebellar arachnoidmembrane to the tentorium was the bridgingveins, including precentral cerebellar veins,veins into the tentorial sinus, and veins intooccipital sinus (2, 10). The tentorium edgesconverge directly to the point where the veinof Galen is located (8). The endoscope wastherefore directed slightly inferior to the ten-torium along a trajectory guided by these sig-nificant landmarks. By means of this method,bridging veins between the top cerebellar andtentorium were coagulated and divided grad-ually.

There was ample room for an endoscopealong this trajectory, and no additional cer-ebellar retraction was required after dis-secting the trabeculae and bridging veins.The reasons for dual burr holes were 1) tofacilitate the bimanual manipulation of in-strument, decreasing the fighting of scopeand instrument; 2) to save time with drillingand resection in comparison to conven-tional large suboccipital craniectomy orcraniotomy; and 3) to decrease the chanceof a potential air-embolism during thebreach of the occipital sinus.

However, the full-endoscopic method isnot free of disadvantages; there some limita-tions, including the following: 1) for a medi-um-sized tumor (�3 cm), it is sufficient todissect the peripheral portion and adjacenttissue, creating enough room to manipulatethe para-pineal window. However, because ofthe bulky nature of the larger tumor, even afterinternal debulking, made the separation diffi-cult. 2) Positional factoring, as the approachimplies, is indicated for midline or paramid-line lesions at the level between the roof of thethird ventricle and upper tectal region. Wehave tried to advance the scope with availableinstruments, but the anterior limit was theforamen of Monro. 3) The texture of the tu-mor, as well as the limited length of certaininstruments, such as the forceps, grasper, cu-rettage, and probe, plays a vital role in deter-mining its resectability. The harder it is tohalve the tumor, the less of it can be resected,and vice versa. 4) The most challenging issueof endoscopic surgery remains hemorrhagic

control under the 2-dimensional scope visual-

399.e4 www.SCIENCEDIRECT.com

zation. We can address some incidental ooz-ng and even intentional vascular ligation withipolar coagulation. However, in the case ofigorous bleeding, this approach should thene converted into open method to take greatontrol of the bleeding source.

We learned that the cystic lesion could beross-totally removed by full-endoscopicesection (4, 7). For solid tumors, the accessepends on the working distance, angle,nd the controlled skills under the two-di-ensional display. From the literature, we

ound that this might be the new techniqueith potential development and insight. In

areful selection of these patients, a full-endo-copic complete resection is promising andemonstrates minimal complications.

ONCLUSION

aking the advantages of the endoscopend peculiar S-C corridor and our conceptf cone anatomy, we could successfully re-ove the gross total tumor without violat-

ng the critical neurovascular structures.oreover, this approach can be performed

egardless of the size of the ventricle. A de-ermination of its long-term efficacy, how-ver, requires that more clinical experiencesre performed for verification.

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eceived 10 February 2011; accepted 13 May 2011

itation: World Neurosurg. (2012) 77, 2:399.e1-399.e4.OI: 10.1016/j.wneu.2011.05.035

ournal homepage: www.WORLDNEUROSURGERY.org

vailable online: www.sciencedirect.com

878-8750/$ - see front matter Crown Copyright © 2012

ublished by Elsevier Inc. All rights reserved.

RY, DOI:10.1016/j.wneu.2011.05.035