Treatment with endoscopic transnasal resection of hypothalamic pilocytic astrocytomas: a single-center experience

Abstract

Backgrounds: Pilocytic astrocytomas (PAs) are World Health Organization (WHO) grade I tumors, which are relatively common, and are benign lesions in children. PAs could originate from the cerebellum, optic pathways, and third ventricular/hypothalamic region. Traditional various transcranial routes are used for hypothalamic PAs (HPAs). However, there are few studies on hypothalamic PAs treated through the endoscopic endonasal approach (EEA). This study reports the preliminary experience of the investigators and results with HPAs via expanded EEAs.

Methods: All patients with HPAs, undergone EEA in our hospital from 2017 to 2019, were retrospectively reviewed. The demographic data, clinical symptoms, complications, skull base reconstruction, prognosis, and endocrinological data were all recorded and analyzed in detail.

Results: Finally, five female patients were enrolled. The average age of patients was 28.6 ± 14.0. All patients had complaints about their menstrual disorder. One patient had severe bilateral visual impairment. Furthermore, only one patient suffered from severe headache due to acute hydrocephalus, although there were four patients with headache or dizziness. Four cases achieved gross-total resection, and one patient achieved subtotal resection. Furthermore, there was visual improvement in one patient (case 5), and postoperative worsening of vision in one patient (case 4). However, only one patient had postoperative intracranial infection. None of the patients experienced a postoperative CSF leak, and in situ bone flap (ISBF) techniques were used for two cases for skull base repair. In particular, ISBF combined with free middle turbinate mucosal flap was used for case 5. After three years of follow-up, three patients are still alive, two patients had no neurological or visual symptoms, or tumor recurrence, and one patient had severe hypothalamic dysfunction. Unfortunately, one patient died of severe postoperative hypothalamus reaction, which presented with coma, high fever, diabetes insipidus, hypernatremia and intracranial infection. The other patient died of recurrent severe pancreatitis at one year after the operation.

Conclusion: Although the data is still very limited and preliminary, EEA provides a direct approach to HPAs with acceptable prognosis in terms of tumor resection, endocrinological and visual outcomes. ISBF technique is safe and reliable for skull base reconstruction.

Keywords: Endoscopic transnasal resection; Hypothalamic; In situ bone flap; Pilocytic astrocytomas.

Fig. 1

The intraoperative view, a 0° angled scope. a Elevation of the In Situ Bone Flap from the dura below it using a Cottle dissector; B: Endoscopic view showing the tumor after pituitary transposition; PS pituitary stalk, PG pituitary gland, OC optic chiasm, TM tumor. c Endoscopic view showing the tumor; III oculomotor nerve; BA basilar artery, PCA posterior cerebral artery, SCA superior cerebellum artery, TM tumor. d After the tumor removal, the endoscopic view shows the exposure of the third ventricle (TV) with the resulting high-flow CSF leakage, and the pituitary stalk (PS), optic chiasm (OC) and transposed pituitary gland (TPG)

Fig. 2

Comparison of the sagittal MRI obtained at pre- and post-operation. a, b: Case 1. The preoperative MRI shows a giant hypothalamic tumor with no clear margin between the tumor and hypothalamic structure. The postoperative CT (after one day) shows the GTR of the tumor and hematocele in the lateral ventricles. c, d: Case 2. The preoperative MRI study shows the suprasellar tumor with solid and cystic portions. The postoperative MRI study obtained at one year after surgery shows that the gland and the stalk were preserved and visible. The tumor was radically resected. e, f: Case 3. The preoperative MRI shows the tumor located suprasellar, interpeduncular and prepontine cistern. The postoperative MRI (6 months) shows the radical resection of the hypothalamic glioma. g, h: Case 4. The preoperative and postoperative (one year) MRI shows the suprasellar hypothalamus glioma with the involvement of the third ventricle. The residual tumor remained stable after the subtotal resection. i, j: Case 5. The preoperative and postoperative (6 months) MRI shows the radical resection of the hypothalamic glioma

Fig. 3

The intraoperative photographs show the harvesting of the “In Situ Bone Flap” and the evolution of the skull base defect postoperative healing. a The dimension of the designed ISBF ranged from one lateral cavernous sinus to the other, and from the planum sphenoidale to the sellar floor; b The elevation of the ISBF from the dura below it using a Cottle dissector; c The endoscopic view shows the intact dura, intercavernous sinus (IS) and optic canal (OC) after removing the In Situ Bone Flap. d–f The postoperative sagittal CT images shows the process of healing of the In Situ Bone Flap, at one day (d), 3 months (e) and 6 months (f), postoperatively