Elsevier

World Neurosurgery

Volume 114, June 2018, Pages e306-e316
World Neurosurgery

Original Article
Is Low-Lying Optic Chiasm an Obstacle to an Endoscopic Endonasal Approach for Retrochiasmatic Craniopharyngiomas? (Korean Society of Endoscopic Neurosurgery -003)

https://doi.org/10.1016/j.wneu.2018.02.178Get rights and content

Highlights

  • Low-lying chiasm can interfere with endoscopic approach for craniopharyngioma.

  • The position of optic chiasm is affected by tumor origin previous surgery.

  • Low-lying chiasm does not alter clinical outcomes including extent of resection.

  • Endoscopic endonasal approach is feasible even in the presence of low-lying chiasm.

Objective

Despite advances in endoscopic techniques, retrochiasmatic craniopharyngiomas (CPs) are difficult to remove completely, because the low-lying optic chiasm often provides an obstacle to an endoscopic endonasal approach. This study aimed to identify the endoscopic surgical outcomes of the retrochiasmatic CP and resolve the issues related to low-lying optic chiasm.

Methods

We reviewed 154 consecutive patients with CP who underwent endonasal endoscopic resection from February 2009 to April 2017 at 2 independent institutions. The topographic relationship of the tumor with the third ventricle, stalk, and optic chiasm and clinical outcomes were investigated.

Results

Retrochiasmatic CPs were found in 142 of 154 patients (92.2%). The median follow-up time was 25 months. Gross total resection and near-total resection were achieved in 113 patients (79.6%) and 21 patients (13.8%), respectively. Postoperative cerebrospinal fluid leaks were found in 16 patients (11.3%). Low-lying and high-lying chiasms were found in 44 patients (31.0%) and 98 patients (69.0%), respectively. Low-lying chiasm did not affect clinical outcomes including the extent of resection. Patients with low-lying chiasm showed a marginal trend for postoperative visual deterioration. The ventricular growth pattern representing the origin of the tumor and previous surgery were significantly associated with the position of the optic chiasm (P = 0.007 and 0.001, respectively).

Conclusions

An endoscopic endonasal approach is an effective surgical approach for retrochiasmatic CP, even in tumors with low-lying chiasm. However, a thorough and careful dissection is necessary to prevent visual deterioration.

Introduction

Craniopharyngioma (CP) is a rare benign tumor of the sellar and parasellar regions. It accounts for 1%–4% of all primary intracranial tumors and has a bimodal age distribution pattern that epidemiologically peaks in children and adults.1, 2, 3, 4 CP rarely undergoes malignant progression, and complete resection of the tumor may be curative.5 When incompletely resected, CP shows a high recurrence rate despite its benign histologic feature.6 Although CP should be treated using combined therapy, surgical removal of the tumor remains the first line of therapy, with a considerable probability of cure.7 However, complete resection is challenging because CP is close to critical structures such as the optic apparatus, pituitary stalk, hypothalamus, and internal carotid artery.8, 9, 10, 11

Recently, endoscopic endonasal surgery for CP has shown a remarkable progress and proved to be safe and effective.8, 12, 13 The endoscopic endonasal approach (EEA) showed successful resection rates compared with conventional transcranial surgeries.14 The advantages of the EEA are accessing the tumor immediately after dural opening and enabling a direct visualization of the surgical plane without brain retraction.13 Despite the advances in endoscopic techniques, CP with a retrochiasmatic-growing pattern remains challenging to completely remove through the EEA, because the low-lying optic chiasm sometimes results in a narrow surgical corridor and blocks the pathway to the tumor.15, 16 In contrast, upward displacement of the optic chiasm by the tumor can provide a wider surgical corridor for the EEA. Therefore, evaluating the topographic relationship between the optic chiasm and the tumor is of major concern for the EEA.10, 11, 17, 18, 19, 20

In this study, we focused on whether the displacement of the optic chiasm affects the clinical results of the EEA for CP. The study aimed to identify the endoscopic surgical outcomes of retrochiasmatic CP and resolve the issues related to the position of the chiasm.

Section snippets

Methods

We retrospectively analyzed 154 consecutive patients with CP who underwent endoscopic endonasal surgery at 2 independent institutions (Seoul National University of Hospital, Seoul, Korea and Samsung Medical Center, Seoul, Korea) from February 2009 to April 2017. An endoscopic skull base team consisting of neurosurgeons (D.K. and D.N.) and an otolaryngologist (S.H.) from Samsung Medical Center and 1 neurosurgeon (Y.K.) from Seoul National University Hospital performed the EEA. Of 154 patients,

Patient Characteristics

Retrochiasmatic CPs were found in 142 of 154 patients (92.2%) initially reviewed (Table 1). The median age of patients at surgery was 43 years (range, 13–75 years), with 10 children and 132 adults. There were 74 male and 68 female patients. The median follow-up time was 25 months (range, 1–98 months). Of the 142 procedures, 101 (71.1%) were the first operation for primary CPs, whereas 41 (28.9%) were operations for recurrent tumors. The median maximal diameter was 2.5 cm (range, 1.0–7.3 cm).

Tumor Control Rates and Related Factor

The rates of GTR after the EEA vary widely, and 66.9% of GTR was reported in a meta-analysis.3 The rate of successful resection decreases substantially for recurrent CPs.3, 11 Regarding the prognostic factors for successful resection, preoperative factors did not affect the rate of successful resection except for treating recurrent tumors. Because total resection of recurrent CP remains a challenge even in experienced hands, the maximal safe tumor resection at the first surgery should be

Conclusions

The low-lying chiasm can interfere with surgical working space during EEA for retrochiasmatic CP. It is frequently found in recurrent tumors or those originating from the infundibulum to the third ventricular chamber. However, EEA is affordable to obtain successful outcomes even in the presence of low-lying chiasm. The experienced surgical techniques could overcome the narrow surgical corridor caused by the low-lying chiasm.

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    Conflict of interest statement: This research was supported by a grant from the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (HI14C3418 and HI16C-1111-020016), a grant (NRF-2015M3A9A7029740, NRF-2015M3C9A1044522, NRF-2015M3A9B5053642, and NRF-2017R1A2B2008412) of the National Research Foundation funded by the Ministry of Science, ICT and Future Planning (MSIP) of Korea, and by a Samsung Medical Center grant.

    Kyung Hwan Kim and Yong Hwy Kim contributed equally to this work.

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