Between 2015 and 2021, Osaka City University Hospital performed surgical resection via EEA as initial treatment for 37 consecutive patients with primary craniopharyngioma. Patients who underwent surgery or radiation therapy prior to this endoscopic endonasal surgery were not included in the present analysis. All cases included in this study were retrospectively analyzed using electronic medical records. Patients comprised 15 males and 22 females with a mean age of 46.8 years (range, 5–80 years). Mean tumor diameter was 27.1 mm (range, 15–78 mm). Table 1 shows the characteristics and detailed clinical information of patients.
All patients underwent preoperative imaging using CT and MRI to assess and identify tumor location, tumor extent, ventricular size, and neurovascular location. Ophthalmological evaluations included visual acuity and visual fields. Endocrinological status was evaluated and anterior pituitary hormone dysfunction was defined as the use of hormone supplementation or the presence of high levels of prolactin without the use of dopamine agonists. Diabetes insipidus was diagnosed before and after surgery based on the sodium level and presence of hypotonic polyuria. Cognitive function was assessed pre- and postoperatively. A patient was considered to show cognitive impairment if any of the following conditions were met: 1) Mini-Mental State Examination score <20 or 2) the patient felt unable to continue previous profession due to the presence of the lesion. BMI (Body Mass Index) was measured in all patients before and after surgery to evaluate obesity. For each patient, Karnofsky Performance Scale (KPS) was retrospectively reviewed through the medical records.
Tumor volume was measured using 3-dimensional contrast-enhanced MRI at a workstation (Synapse-Vincent, FUJIFILM Medical Co., Ltd.), and the extent of tumor resection achieved was calculated using MRI data from preoperatively and 1 week postoperatively. Gross total resection (GTR) was defined as the absence of residual lesions or residual calcification. Near-total resection (NTR) was defined as residual lesion or calcification <0.5 cm3. Subtotal resection (STR) was defined as a residual lesion or calcification ≥0.5 cm3. Follow-up MRI was performed at regular intervals within 1 week and 3 months after surgery, and again after 6–12 months. Tumor recurrence during follow-up was defined as the appearance of a new lesion on MRI or the growth of residual tumor.
In addition, we investigated historical changes in surgical procedures and outcomes for craniopharyngioma at a single institute. Patients were divided into two groups for comparison based on the timing of surgery: a previous treatment group (n = 28), with patients between 2009 and 2014 treated mainly using several microscopic transcranial approaches, and a recent treatment group (n = 37), with patients between 2015 and 2021 treated mainly via EEA.
Craniopharyngiomas were classified based on location, origin, and preoperative growth pattern. The five groups defined in our classification scheme and used to select the appropriate surgical management were intrasellar, prechiasmatic, retrochiasmatic, intra-third ventricle, and large lobulated types (Fig 1). Intrasellar-type craniopharyngioma originates from the intrasellar part of the pituitary stalk. With this lesion type, the sellar floor is usually enlarged in a manner similar to that seen in pituitary adenoma. The prechiasmatic type originates from the anterior part of the stalk and grows in an upward direction. Upward elevation of the optic chiasm and anterior communicating artery is also seen, with the tumor extending laterally. Retrochiasmatic-type craniopharyngioma originates from the posterior part of the pituitary stalk and grows up toward the posterior fossa. The optic chiasm and anterior communicating artery remain in their normal positions. The intra-third ventricle type originates from the floor of the third ventricle. Finally, multi-lobular tumors over 4 cm in diameter are defined as the large lobulated type.
The basic surgical procedure via EEA is as follows. First, a nasoseptal mucosal flap is harvested. The sphenoid sinus and posterior ethmoid sinus are opened widely, then the tuberculum sellae and sella turcica are drilled out. For prechiasmatic-type lesions, the planum sphenoidale and medial inferior wall of the optic canal are also removed. For retrochiasmatic, intra-third ventricle, or large lobulated lesions, additional removal of the dorsum sellae, upper clivus and posterior clinoid process is performed, and the pituitary gland is detached from the medial wall of the cavernous sinus and transposed from one side to the other for complete exposure of the lesion. Furthermore, for large blobulated-type lesions with lateral extension beyond the internal carotid artery (ICA), oculomotor nerve, and posterior communicating (P-com) artery, combined surgery with EEA and a transcranial approach is selected. The pituitary stalk is preserved if allowed by its positional relationship with the tumor. If the tumor is found to be tightly adherent to the optic pathway, hypothalamus, or arteries including small perforating arteries from the ICA or P-com artery, tumor resection is stopped. Skull base reconstruction involves multi-layered reconstruction to prevent leakage of cerebrospinal fluid (CSF).
Figure 1 shows our surgical strategy for craniopharyngioma via EEA based on the anatomical sub-classification.
Case 1: Intrasellar type
An intrasellar lesion was detected in an 15-year-old boy suffering from visual dysfunction. Preoperative CT and MRI demonstrated characteristic findings of the intrasellar type of craniopharyngioma (Fig 2A-C). The bone was removed from the sellar floor to the tuberculum sellar (Fig 2F). The tumor was then carefully dissected off any adjacent critical neurovascular structures (Fig 2G,H) and totally removed with preserving pituitary gland and stalk (Fig 2D,E,I). Postoperatively, anterior pituitary function was maintained.
Case 2: Prechiasmatic type
A 44-year-old female exhibiting a deterioration of her visual acuity on the right side was referred to our hospital. Preoperative CT and MRI demonstrated there was elevation of the optic chiasm and anterior communicating artery (Fig 3A-C). The bone was removed from the sellar floor to planum sphenoidale and medial inferior wall of the optic canal are also removed (Fig 3F). After displacing the normal pituitary gland (Fig 3G,H), the tumor capsule was peeled from the stalk and optic chiasm (Fig 3I,J). The tumor was totally removed with preserving the stalk (Fig 3E,F,K). Postoperatively, visual dysfunction improved and anterior and posterior pituitary function were maintained.
Case 3: Retrochiasmatic type (Video 1)
Retrochiasmatic-type craniopharyngioma with hydrocephalus was identified in a 5-year-old girl with headache, vomiting and bitemporal hemianopsia (Fig 4A–D). After bone removal from the bottom of the sella turcica to the tuberculum sellae, the upper clivus, dorsum sellae and bilateral posterior clinoid processes were removed (Fig 4H). Tumor in the retrochiasmatic region was confirmed after displacing the normal pituitary gland (Fig 4I). After internal decompression of the tumor, the tumor was detached from the optic chiasm, perforating arteries branching off the ICA and P-com artery (Fig 4J). The boundary of the wall of third ventricular was confirmed (Fig 4K). As a result, complete removal of the tumor was achieved (Fig 4E–G,L,M). Improvement of neurological symptoms was observed postoperatively. She started anterior and posterior pituitary hormone replacement therapy and is currently living a normal life without any problems.
Case 4: Intra-third ventricle type
An intra-third ventricle craniopharyngioma with hydrocephalus was identified in a 20-year-old man (Fig 5A–C). After bone removal from the bottom of the sella turcica to the tuberculum sellae, additional bony removal of the dorsum sellae, upper clivus and bilateral posterior clinoid processes was performed (Fig 5F). The tumor developed continuously to the infundibular recess. Therefore, preservation of the pituitary stalk was judged likely to prove difficult, so the stalk was cut (Fig 5G). An incision was made in the tumor and internal decompression of the tumor was initiated (Fig 5H). The boundary of the wall of the third ventricle was confirmed (Fig 5I). After grasping and peeling only the tumor capsule from the wall of the third ventricle, the tumor was completely removed (Fig 5E,F,J,K).
Case 5: Large lobulated type with lateral extension (Video 2)
A 5-year-old girl presented with a history of worsening visual dysfunction for a few months and recent right oculomotor nerve palsy. Intracranial images showed a large, lobulated craniopharyngioma with lateral extension (Fig 6A–D). Combined surgery with EEA and a microscopic transcranial approach was applied to completely remove the tumor, including the tumor capsule, in a single stage. After bone removal from the sella turcica to the tuberculum sellae, additional bony removal of the dorsum sellae, upper clivus and bilateral posterior clinoid processes was performed via EEA (Fig 6H). After the pituitary gland was displaced to the left, the lesion inside the circle of Willis was removed while detaching the tumor and pituitary stalk (Fig 6I). At the same time, after frontotemporal craniotomy (Fig 6J), the tumor capsule was detached from the deep Sylvian vein and brain surface, and gradually dropped toward the sellar area via a transcranial approach (Fig 6K). After removal of the posterior component of the tumor, the hypothalamus and brainstem were decompressed via EEA (Fig 6L). Finally, the tumor was completely removed with preservation of the pituitary stalk (Fig 6E–G,M). Postoperatively, oculomotor nerve palsy and visual dysfunction improved, and anterior pituitary function was maintained.