Fully Endoscopic Resection of an Epidermoid Cyst of the Pineal Region: Two-Dimensional Operative Video

Key message: The video clearly shows how the resection strategy is the same and employs the same instruments that would have been used in an open surgical approach. This minimally invasive technique causes less damage to normal structures and results in fewer sequelae for our patients. Video link https://youtu.be/dIofN6jHD2A QR Code: Video timeline with audio transcript 00:00-00:06: In this operative video, we present the fully endoscopic resection of an epidermal cyst of the pineal region. 00:09-00:32: This was a 12-year-old patient, previously healthy, who presented at the emergency department of our hospital with a 3-week history of severe headaches and daily vomiting. These symptoms had worsened in the past few days, and there was a tendency to sleep excessively. A neurological examination did not show any focal deficit, and a fundus examination revealed papilledema. 00:33-01:07: In the first instance, a brain CT was performed, in which an expansive brain lesion was observed in the pineal region and the posterior sector of the third ventricle with associated hydrocephalus and trans ependymal edema. This motivated us to perform a brain MRI which revealed a rounded image with defined contours of 15 mm in diameter, hyperintense on T2 and hypointense on T1, with restricted diffusion. Our diagnostic imaging impression was of an epidermoid cyst. 01:07-01:13: Rationalized for the procedure was based on the patient's symptomatic condition and the need for tissue diagnosis. 01:13-01:21: We analyzed the different approaches for this lesion, evaluating the advantages and disadvantages of each of the possible surgical approaches. 01:22-01:36: We choose a pure endoscopic inter-ventricular approach being a minimally invasive procedure. This allows us to treat the hydrocephalus by performing an ETV. Additionally, it enabled us to take a biopsy and eventually perform a tumor resection. 01:37-01:46: Alternative management to endoscopic surgical approaches is conservative management with follow-up after hydrocephalus treatment or open microsurgery approaches. 01:47-02:28: The patient was placed in a supine position with a 45-degrees head flexion. We use a rigid Decq Karl Storz 30 degrees endoscope with the aim of performing the ETV and approaching the tumor lesion. We plan a single burr hole with neuronavigational guidance between both approaches. 02:09-02:23: Our first step was to perform an ETV. Subsequently, we conducted a biopsy of the lesion to obtain pathological results. After this, we conducted the endoscopic pure resection of the lesion. 02:24-02:38: We entered the right later ventricle with a rigid endoscope and performed a standard fashion ETV fenestrating the liliequist membrane being a successful procedure. 02:39-02:50: Then we rotated 180 degrees in the rigid endoscope to get a better viewing of the posterior region of the third ventricle. 02:51-03:10: Once entered the posterior third ventricle. we could observe this irregular rounded lesion covered by an ependyma layer. Upon ependymal correlation, we could observe a brightly pearly white tumor, with an operative appearance of an epidermoid cyst. 03:11-03:21: A tissue sample was obtained for pathological examination. The intra-operative results confirmed the suspicion of an epidermoid cyst. 03:22-03:42: After opening the tumor capsule, we use a cannula aspiration to aspirate the tumor content. Epidermoid cyst complete resection is the treatment of choice. A minimally invasive endoscopic pure approach can achieve this in a safe manner. 03:43-04:12: We use different endoscopic maneuvers to dissect the tumor membrane for the third ventricle wall. Careful dissection and preservation of the normal tissue are mandatory. Biopsy forceps were used to perform the cystic capsule resection using the rotation and traction maneuver. This approach prevented abrupt tearing and made the resection more controlled. 04:13-04:34: Unlike the adhered capsule, the content of the cyst was resected more easily. This allowed us to employ different techniques such as removing it with forceps or suctioning it with an aspiration cannula. As a result, we achieved macroscopically complete resection of the entire cyst contents. 04:35-04:58: So the surgical strategy employed was first to incise and open the capsule, performing a content debulking of the tumor. Then this provides a better visualization and a working space where we could achieve a dissection and resection of the capsule completely. 04:58-05:10: The dissection and piecemeal resection was achieved using the coagulation, the biopsy forceps, the microscissors, and the hydric dissection maneuver. 05:11-05:18: We can observe how gradually the aqueduct which was compressed by the lesion is being released. 05:19-05:42: The most challenging part of the resection was removing the tumor capsule membrane which was heavily adhered to the posterior portion of the third ventricle. This requires extreme delicacy during the resection process to avoid any abrupt maneuver, trying not to damage any vascular or nerve tissue. 05:43-06:06: Direct and angle visualization of all the structures allows us to obtain a panoramic view and enhance our understanding of the region as we proceed with the resection. When operating on complex tumors, like in this case, experience and the adequate neuroendoscopy set instrument are mandatory. 06:06-06:35: Working with a different instrument allows us to dissect, coagulate, and resect the complete tumor, not only the content but also the membrane achieving the goal. The usefulness of working with a two-channel rigid neuro endoscope allows us to work just as if this was a microsurgical case. 06:36-07:04: Bimanual instrument maneuver: Dissection, coagulation, and resection allow us to treat this tumor in this very delicate area. During the final stages of the resection, we utilize dual instrumentation, which enables us to resect the more complex portion of the lesion without damaging the nearby structure or causing bleeding. 07:04-07:23: This approach proved to be very effective in ensuring precision and safety throughout the procedure. Avoiding bleeding is essential in this water-medium surgical procedure, given that a very little amount of blood can obscure all our vision. 07:23-08:03: The importance of this case is to consider these pure endoscopic minimal invasive approaches to treat a vascular or less than three centimeters lesion in this complex region. Being a safe and efficacy procedure, the video shows how the resection strategy and endoscopic instruments have the same concept as in an open surgical approach. This minimally invasive technique causes less damage to normal structures and results in fewer sequelae to our patients. 08:04-08:18: It is crucial to emphasize the importance of using appropriate instrument equipment and having a very experienced neurosurgical team. This combination allows us for successful and safer surgeries. 08:19-08:35: After the complete tumor removal, we observe that the aqueduct is clear and patent. The removal of the endoscope is always done under visual monitoring to ensure that there is no bleeding or complication before concluding the procedure. 08:36-08:45: In the post-operative MRI, we can observe the complete tumor resection in the T2- weighted images and the diffusion-weighted images. 08:45-09:04: Epidermal cysts are benign congenital lesions of ectodermal origin, representing 1% of primary intra-cranial tumors. They can be located in any region of the neuraxis. Locations at the third ventricle and pineal region are extremely rare. 09:04-09:30: Management of intra-cranial epidermoid cyst depends on different factors. If it is an incidental asymptomatic lesion, it can be safely monitored. But if it is a symptomatic or growing lesion, it should be ideally treated with an ETV for hydrocephalus if present, along with a biopsy of the lesion and, if possible, a complete surgical resection. 09:31-09:44: The post-op patient's recovery was uneventful, with no neurological deficit. During a 6-year follow-up period, the patient's MRI control did not reveal any recurrence. 09:44-10:02: In conclusion, in our experience, the minimal invasive pure endoscopic transventricular approach stands as a viable and effective technique for resecting tumours in the pineal region or posterior third ventricle, particularly in carefully selected cases. Pearls and pitfalls Selected lesions in the pineal region, like our case of an avascular epidermoid cyst with a diameter of less than 3 cm, can be resected using a purely minimally invasive endoscopic technique. This approach translates the knowledge, techniques, and maneuvers utilized in conventional microsurgery. Declaration of patient consent A full and detailed consent from the patient/guardian has been taken. The patient's identity has been adequately anonymized. If anything related to the patient's identity is shown, adequate consent has been taken from the patient/relative/guardian. The journal will not be responsible for any medico-legal issues arising out of issues related to patient's identity or any other issues arising from the public display of the video. Disclosures The authors hereby certify that the work shown here is genuine, original and not submitted anywhere, either in part or full. They transfer the full rights of the video to Neurology India. All the necessary permissions from the patient, hospital and institution has been taken for submitting this video to Neurology India. Previous presentation This material has not been presented before. Previous publication This material has not been published before. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.