TECHNICAL NOTE
J Neurosurg 134:1198–1202, 2021

Clip retraction of the tentorium: application of a novel
technique for tentorial retraction during supracerebellar
transtentorial approaches
*Jacob F. Baranoski, MD, Ankush Bajaj, BS, Colin J. Przybylowski, MD, Joshua S. Catapano, MD,
Fabio A. Frisoli, MD, Michael J. Lang, MD, and Michael T. Lawton, MD
Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona

Supracerebellar transtentorial (SCTT) approaches have become a popular option for treatment of a variety of pathologies in the medial and basal temporal and occipital lobes and thalamus. Transtentorial approaches provide numerous
advantages over transcortical approaches, including obviating the need to traverse eloquent cortex, not requiring parenchymal retraction, and circumventing critical vascular structures. All of these approaches require a tentorial opening, and
numerous techniques for retraction of the incised tentorium have been described, including sutures, fixed retractors, and
electrocautery. However, all of these techniques have considerable drawbacks and limitations. The authors describe a
novel application of clip retraction of the tentorium to the supracerebellar approaches in which an aneurysm clip is used
to suspend the tentorial flap, and an illustrative case is provided. Clip retraction of the tentorium is an efficient, straightforward adaptation of an established technique, typically used for subtemporal approaches, that improves visualization
and surgical ergonomics with little risk to nearby venous structures. The authors find this technique particularly useful for
the contralateral SCTT approaches.
https://thejns.org/doi/abs/10.3171/2020.2.JNS192952

KEYWORDS cavernous malformation; supracerebellar infratentorial approach; supracerebellar transtentorial approach;
surgical technique; tentorium; vascular disorders

T

he tentorium is a free dural structure that can
be incised and retracted to expand exposures of
deep medial anatomical regions. Subtemporal approaches to the basilar bifurcation or trunk for aneurysm
clipping employ this technique routinely, incising the tentorium posterior to the entry of the trochlear nerve into
its dural sleeve and connecting the middle and posterior
cranial compartments.1,2 The posterior tentorial leaflet is
typically reflected laterally and held in place with a stay
suture. Hernesniemi et al.3 introduced a clever technique
that simplified this maneuver, making a second incision in
the tentorium laterally and using an aneurysm clip to hold
the folded leaflet in the blades of the clip, with one blade
passing through the tentorial incision. This “clip retraction” technique was widely accepted as being easier and

quicker than the use of sutures and is now almost a standard step in the subtemporal approach.
Recently, supracerebellar transtentorial (SCTT) approaches have become a popular option for treatment of
a variety of pathologic conditions in the medial and basal
temporal and occipital lobes.4–6 Lesions such as meningiomas,7 gliomas, cavernous malformations (CMs),8–10
and arteriovenous malformations11,12 have been removed
through posterior approaches through the tentorium, often
with the use of the sitting position and gravity retraction
of the cerebellum to widen the supracerebellar space and
extend the upward reach beyond the tentorium. We and
others have found this strategy useful for the treatment of
thalamic pathologic entities that abut the posterior-inferior
surface of the pulvinar.8,10,​13,14 Transtentorial approaches

ABBREVIATIONS CM = cavernous malformation; PCA = posterior cerebral artery; SCTT = supracerebellar transtentorial.
SUBMITTED October 30, 2019. ACCEPTED February 4, 2020.
INCLUDE WHEN CITING Published online April 24, 2020; DOI: 10.3171/2020.2.JNS192952.
* J.F.B. and A.B. contributed equally to this work.
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Baranoski et al.

With use of the two-point method,13 we determined that
the location of the lesion was ideal for a contralateral
SCTT approach, with the patient in the sitting position.9
After an appropriate preoperative workup that included an
echocardiogram with a bubble study, patient consent was
obtained, and the patient was scheduled for surgery.

FIG. 1. Preoperative axial T2-weighted MR image showing a CM located
in the right posterior medial temporal lobe.

obviate the need to traverse eloquent cortex, which makes
these approaches preferable for the treatment of parenchymal lesions in the dominant hemisphere. Transtentorial
approaches also circumvent key vascular structures, such
as the vein of Labbé.
By definition, transtentorial approaches require a tentorial opening to reach their target lesion.8,9,15 Numerous
techniques for retraction of the incised tentorium have
been described, including sutures, fixed retractors, and
electrocautery.4 However, to our knowledge, no one has
adapted the technique described by Hernesniemi et al.3 for
obtaining subtemporal exposures to attaining SCTT exposures. In this paper, we describe the novel application of
clip retraction of the tentorium to obtain a supracerebellar
approach in a case of a right posterior medial temporal
lobe CM resection. We find this ergonomic technique particularly useful with the contralateral SCTT approach, in
which the lateral exposure is more extreme than with the
ipsilateral SCTT approach.9

Case Presentation and Technical Note

History and Examination
A 65-year-old woman presented with seizures that were
recurrent despite the administration of maximal medical
therapy. Diagnostic imaging findings indicated a nonenhancing lesion in the right posterior medial temporal lobe
that was 1.5 cm in diameter, consistent with a CM (Fig.
1). Because of the patient’s medically refractory seizures,
microsurgical resection of the CM was recommended.

Operative Technique
The patient was placed in the sitting position, a midline suboccipital incision was made, and a suboccipital
craniotomy eccentric to the left side was performed that
exposed the left transverse sinus and the edge of the left
torcula. The dura was opened and flapped superiorly,
which placed gentle traction on the left transverse sinus
and exposed the supracerebellar infratentorial corridor.
Cerebrospinal fluid drainage and the gravity retraction afforded by the sitting position allowed for ample relaxation
of the cerebellum. Arachnoid dissection with preservation
of the cerebellar veins allowed for further widening of
the supracerebellar infratentorial corridor. Dissection was
continued anteriorly to the quadrigeminal cistern, which
exposed the posterior cerebral artery (PCA), trochlear
nerve, and vein of Galen. Intraoperative neuronavigation
identified the necessary trajectory to the right posterior
medial temporal lobe CM through the tentorium, and a
corresponding tentorial flap was planned. The tentorium
was sharply transected transversely (Fig. 2A). A separate
small incision was made in the tentorial dura laterally to
accommodate one blade of the aneurysm clip. The posterior leaflet of incised tentorium was folded laterally, and a
straight aneurysm clip was used to retract the leaflet. One
of the clip’s blades was inserted through the lateral tentorial incision, and the other blade held the tentorial flap
against the tentorium. This maneuver suspended the tentorial flap to enhance visualization and operative maneuverability within the surgical corridor (Fig. 2B–D). This maneuver was faster and simpler than securing the tentorial
flap with a deep stitch in a relatively tight corridor.
With the tentorium incised and the flap clipped to the
adjacent tentorium, the CM was easily identified in the
right posterior medial temporal lobe, with its associated
hemosiderin staining of the parenchyma. The CM was circumferentially dissected and was resected in its entirety.
After resection, the aneurysm clip was removed to free the
tentorial flap. A watertight dural closure was performed,
and the remainder of the case proceeded in a standard
fashion.
Postoperative Course
The patient tolerated the procedure very well. Postoperative imaging confirmed complete resection of the CM
(Fig. 3). At her 6-week follow-up examination, the patient
had made a complete recovery and exhibited no neurological deficits.

Discussion

Because of their advantages over transcortical approaches, SCTT approaches are becoming more common
for the treatment of pathologic conditions in the posterior
thalamus and medial temporooccipital space. Previous
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ABOVE

FIG. 2. Intraoperative photographs showing (A) the sharp opening of the
tentorium to create the tentorial flap, (B) exposure of the CM after clip
retraction of the tentorium, and (C) the surgical corridor (dashed outline)
afforded by the clip retraction technique, which provides excellent visualization of the lesions as well as surgical ergonomics. Note the straight
aneurysm clip with one of the clip’s blades inserted through a separate
tentorial incision and the other blade securing the tentorial flap against
the tentorium. D: A higher magnification view of the surgical corridor
(dashed outline) is also shown. Used with permission from Barrow
Neurological Institute, Phoenix, Arizona.
RIGHT

FIG. 3. Postoperative axial T2-weighted MR image showing complete
resection of the CM.

studies have characterized the use of either SCTT or occipital transtentorial approaches for the microsurgical resection of meningiomas,4,6,16 CMs,8–10 epidermoid cysts,17
and other pathologic conditions.11,12,​18,19 Compared with
transcortical routes, transtentorial approaches provide excellent anatomical exposure without traversal of eloquent
cortex or retraction of parenchyma. However, a limitation
of these transtentorial approaches is the narrow corridor
through the tentorium, which may hinder visualization
or limit the dexterity of the surgeon. The clip retraction
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FIG. 4. Illustrations of the clip retraction technique for securing the tentorium with the use of a straight aneurysm clip, demonstrating (A) the location of the tentorial cut (dashed line), (B) the separate incision made in the tentorium to accommodate the blade of
the clip, and (C) the placement of the clip retracting the tentorial flap against the tentorium and the exposure that this technique
affords. BVR = basal vein of Rosenthal; IOV = internal occipital vein; PCV = precentral cerebellar vein; Tent. = tentorium; VOG =
vein of Galen. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

technique described herein quickly and easily secures
the tentorial flap and prevents the flap from obscuring
the surgical field, thereby improving the SCTT approach
(Fig. 4).
Conventional techniques for mobilizing the incised
tentorium include the use of sutures, fixed retractors, electrocautery, or large flaps. Stitching the tentorium at this
depth and with the patient in the sitting position can be
cumbersome, and retractors obscure the surgical field.
Other neurosurgeons have offered alternatives to tentorial
flap suspension. In 2012, de Oliveira et al.20 published a
series of SCTT approaches in which they completely resected a portion of the tentorium, as opposed to creating a
flap. Although this technique works well, it also has considerable drawbacks that include the need for additional
tentorial incisions, management of bleeding from tentorial
sinuses, injury to tentorial draining veins, and morbidity
associated with venous occlusion.
Clip retraction of the tentorium is an efficient, straightforward adaptation of an established technique typically
used for subtemporal approaches that incise the tentorium. Clip retraction improves visualization and surgical
ergonomics with little risk to nearby venous structures.
Elsewhere, we have reported our use of aneurysm clips to
anchor slings to dural sleeves in the clivus for macrovascular decompressions of the vertebral and basilar arter-

ies.21 This posterior clip retraction of the tentorium may
be viewed as another example of the utility of aneurysm
clips anchored to the dura to mobilize and hold obstructive
anatomical features or compressive pathologic entities.

Acknowledgments

We thank the staff of Neuroscience Publications at Barrow
Neurological Institute for assistance with manuscript preparation.

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Disclosures

The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this
paper.

Author Contributions

Conception and design: Lawton, Baranoski. Acquisition of data:
all authors. Analysis and interpretation of data: all authors. Drafting the article: Baranoski, Bajaj. Critically revising the article: all
authors. Reviewed submitted version of manuscript: all authors.
Approved the final version of the manuscript on behalf of all
authors: Lawton. Study supervision: Lawton, Baranoski.

Correspondence

Michael T. Lawton: c/o Neuroscience Publications, Barrow
Neurological Institute, St. Joseph’s Hospital and Medical Center,
Phoenix, AZ. neuropub@barrowneuro.org.

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