Endoscopic Keyhole Approach for Intracranial Epidermoid

Abstract

Objective In contemporary neurosurgical practice, keyhole endoscopic approach has established its role in various neurosurgical pathologies. Intracranial epidermoid is an ideal pathology for endoscopic keyhole approach as epidermoid is well encapsulated, extra-axial, avascular, and easily suckable. The objective of this study is to share our experience of endoscopic keyhole approach for intracranial epidermoids at various locations as a new minimally invasive neurosurgical approach to deal with these lesions. Materials and Methods We conducted a retrospective study on 26 patients who underwent keyhole pure endoscopic excision of intracranial epidermoid between July 2015 and December 2019. Patient's demographics, clinical features, radiological imaging, and postoperative complications were noted. Follow-up outcome of preoperative symptoms and postoperative complications were also analyzed. Results The mean age of the study population was 30.5 years with a mean follow-up of 30 months. The common presenting features were headache, hearing loss, and trigeminal neuralgic pain. Gross total resection was achieved in 73.1% cases, while near total resection and subtotal resection were achieved in 19.2 and 7.7% cases, respectively. In the follow-up, maximal improvement was seen in trigeminal neuralgic pain (83%) and headache (66.7%). Major postoperative complications were facial nerve paresis, lower cranial nerve paresis, and transient facial hypoesthesia, most of which improved over time. None of the patients required resurgery till date. Statistical Analysis Patients' data were analyzed using SPSS software version 23 (Statistical Package for Social Sciences, IBM, Chicago, United States). Conclusion This study demonstrates that with careful patient selection, endoscopic keyhole excision of epidermoid is a good alternative to conventional microsurgical excision with comparable surgical and functional outcomes.

Keywords: endoscopic; epidermoid; intracranial; keyhole; minimally invasive techniques; pure; tailored craniotomy.

Fig. 1

Difference in surgical field view of microscope and endoscope: ( A ) the “funnel-shaped” view of surgical corridor of a microscope and ( B ) “reverse funnel-shaped” view of surgical corridor of endoscope facilitating the panoramic vision of surgical field.

Fig. 2

Right Sylvian fissure epidermoid operated by endoscopic keyhole approach: ( A ) the surface marking of craniotomy and linear incision, ( B ) craniotomy defect measuring ∼2.5 cm, ( C ) preoperative axial magnetic resonance (MR) image in diffusion-weighted imaging (DWI) sequence, and ( D ) postoperative axial MR image (DWI) showing near total excision with residual tumor left.

Fig. 3

Diagrammatic illustration of “two surgeons four-hands technique”: assistant holds the endoscope with both hands, while surgeon holds the suction with left hand and forceps with the right hand.

Fig. 4

Instruments frequently used in endoscopic keyhole approach.

Fig. 5

Major symptoms of patients with their frequency.

Fig. 6

Preoperative magnetic resonance (MR) imaging of a patient with interhemispheric epidermoid: ( A ) diffusion-weighted axial image showing the lesion with focal diffusion restriction and ( B ) postcontrast T1-weighted coronal image showing hypointense lesion without contrast enhancement causing mass effect over corpus callosum. Postoperative MR imaging of the same patient: ( C, D ) diffusion-weighted axial and T1 postcontrast images showing the complete excision of lesion.

Fig. 7

( A ) Preoperative and ( B ) postoperative magnetic resonance (MR) images (diffusion-weighted imaging [DWI]) of large quadrigeminal cistern epidermoid with complete excision, ( C ) preoperative and ( D ) postoperative MR image (DWI) of another patient of quadrigeminal cistern epidermoid with subtotal excision.

Fig. 8

Preoperative magnetic resonance (MR) imaging of a patient with cerebellopontine (CP) angle epidermoid: ( A ) T2-weighted axial image showing the hyperintense mass lesion extending from CP angle cistern toward basal cisterns with mass effect over brain stem and ( B ) diffusion-weighted imaging (DWI) sequence showing diffusion restriction of mass. Postoperative MR imaging of the same patient: ( C ) T2-weighted axial images and ( D ) DWI showing complete removal of tumor.

Fig. 9

Various intraoperative corridors in cerebellopontine angle epidermoid ( A ) between superior petrosal vein and seventh–eighth nerve complex and ( B ) between seventh–eighth nerve complex and lower cranial nerve complex.