Extended Endoscopic Endonasal Approach for Giant Pediatric Craniopharyngiomas: Technical Note and Case Series

BACKGROUND AND OBJECTIVES

Giant pediatric craniopharyngiomas are rare tumors whose clinical and surgical management is extremely challenging. A variety of open transcranial approaches has been used to resect these lesions. Although there has been an increasing acceptance of the endoscopic endonasal approach (EEA) for the resection of pediatric craniopharyngiomas in recent years, many surgeons continue to recommend against the use of the EEA for giant pediatric craniopharyngiomas. This study aimed to evaluate the feasibility of extended EEA for giant craniopharyngiomas in the pediatric population.

METHODS

All consecutive pediatric patients with giant craniopharyngiomas (diameter >4 cm) who underwent endoscopic endonasal surgery at our institution were retrospectively reviewed. Data on demographic information, preoperative assessment, imaging features, surgical results, complications, and recurrences were recorded and analyzed.

RESULTS

A total of 16 pediatric patients with an average age of 12 years were identified. The mean maximum diameter and volume of the tumors were 4.35 cm and 24.1 cm 3 , respectively. Gross total resection was achieved in 13 patients (81.3%) and subtotal resection in 3 patients (18.7%). Postoperatively, partial or complete anterior pituitary insufficiency occurred in 100% of patients, and 62.5% developed new-onset diabetes insipidus. Visual function improved in 9 patients (56.3%) and remained stable in 7 patients (43.7%). Postoperative cerebrospinal fluid leakage occurred in 2 patients and was successfully repaired through the EEA. During a mean follow-up of 44.3 months, 18.8% of patients had a >9% increase in body mass index, and 93.8% of patients successfully returned to school or work. Two patients (12.5%) suffered a recurrence. Disease control was achieved in 16 patients (100%) at final follow-up.

CONCLUSION

The extended EEA allows adequate access to this challenging tumor and enables complete resection and visual improvement with a reasonable approach-related complication rate.

Expanded endoscopic endonasal transsphenoidal approach to determine morphological characteristics and clinical considerations of the cavernous sinus venous spaces

The study aimed at investigating the morphological characteristics and interconnected regularities of the cavernous sinus (CS) venous spaces using an expanded endoscopic endonasal transsphenoidal approach. Surgical dissections were performed for 15-colored silicon-injected human head specimens. The CS venous spaces were examined for their morphological and clinical characteristics using an expanded endoscopic endonasal transsphenoidal approach. The intracavernous course of the internal carotid artery (ICA) divided the CS venous spaces into four interconnected virtual compartments: medial, anteroinferior, posterosuperior, and lateral. The CS venous spaces had peculiar morphological characteristics; the medial compartment was C-shaped while the anteroinferior compartment resembled a boat's bow. The mean distances from the medial border of the inferior horizontal segment of cavernous ICA to the mid-line of the pituitary gland (PG) were 6.07 ± 1.61 mm (left) and 5.97 ± 1.89 mm (right); the mean distances from the medial border of the subarachnoid segment of cavernous ICA to the mid-line of the PG were 5.77 ± 1.16 mm (left) and 5.63 ± 1.17 mm (right); the mean distances from the medial border of the anterior vertical segment of cavernous ICA to the mid-line of the PG were 10.27 ± 1.74 mm (left) and 10.47 ± 1.90 mm (right). Morphological characteristics and the knowledge of the interconnected regularities of the CS venous spaces may help surgeons accurately locate the neurovascular structure, and thus may contribute to the effective prediction of tumor invasion and extension during endoscopic CS surgery.

Additive Manufacturing for Personalized Skull Base Reconstruction in Endoscopic Transclival Surgery: A Proof-of-Concept Study

BACKGROUND

Endoscopic transnasal transclival intradural surgery is limited by a high postoperative cerebrospinal fluid leak rate. The aim of this study was to investigate the role of three-dimensional printing to create a personalized, rigid scaffold for clival reconstruction.

METHODS

Two different types of clivectomy were performed in 5 specimens with the aid of neuronavigation, and 11 clival reconstructions were simulated. They were repaired with polylactide, three-dimensional-printed scaffolds that were manually designed in a computer-aided environment based either on the real or on the predicted defect. Scaffolds were printed with a fused filament fabrication technique and different offsets. They were positioned and fixed either following the gasket seal technique or with screws. Postdissection radiological evaluation of scaffold position was performed in all cases. In 3 specimens, the cerebrospinal fluid leak pressure point was measured immediately after reconstruction.

RESULTS

The production process took approximately 30 hours. The designed scaffolds were satisfactory when no offset was added. Wings were added during the design to allow for screw positioning, but broke in 30% of cases. Radiological assessment documented maximal accuracy of scaffold positioning when the scaffold was created on the real defect; accuracy was satisfactory when the predicted clivectomy was performed under neuronavigation guidance. The cerebrospinal fluid leak pressure point was significantly higher when the scaffold was fixed with screws compared with the gasket technique.

CONCLUSIONS

In this preclinical setting, additive manufacturing allows the creation of customized scaffolds that are effective in reconstructing even large and geometrically complex clival defects.

Endoscopic Endonasal Transclival Resection of a Pontine Metastasis: Case Report and Operative Video

BACKGROUND AND IMPORTANCE

Brainstem lesions are challenging to manage, and surgical options have been controversial. Stereotactic radiosurgery (SRS) has been used for local control, but life-threatening toxicities from 0% to 9.5% have been reported. Several microsurgical approaches involving safe entry zones have been developed to optimize the exposure and minimize complications in different portions of the brainstem, but require extensive drilling and manipulation of neurovascular structures. With recent advancements, the endoscopic endonasal approach (EEA) can provide direct visualization of ventral brainstem. No case has been reported of EEA to remove a brainstem metastasis.

CLINICAL PRESENTATION

We present an illustrative case of a 68-yr-old female with metastatic colon cancer who presented with 2.8 × 2.7 × 2.1 cm (7.9 cm3) heterogeneously enhancing, right ventral pontine lesion with extensive edema. She underwent endoscopic endonasal transclival approach, and gross total resection of the lesion was achieved.

CONCLUSION

The endoscopic approach may offer certain advantages for removal of ventral brainstem lesions, as it can provide direct visualization of important neurovascular structures, especially, if the lesion displaces the tracts and comes superficial to the pial surface.

Endoscopic endonasal surgery to treat intrinsic brainstem lesions: correlation between anatomy and surgery

OBJECTIVE

The endoscopic endonasal approach (EEA) has been proposed as an alternative in the surgical removal of ventral brainstem lesions. However, the feasibility and limitations of this approach to treat such pathologies are still poorly understood. This study aimed to report our experience in five consecutive cases of intrinsic brainstem lesions that were managed via an EEA, as well as the specific anatomy of each case.

METHODS

All patients were treated in a single center by a multidisciplinary surgical team between 2015 and 2019. Before surgery, a dedicated anatomical analysis of the brainstem safe entry zone was performed, and proper surgical planning was carried out. Neurophysiological monitoring was used in all cases. Anatomical dissections were performed in three human cadaveric heads using 0° and 30° endoscopes, and specific 3D reconstructions were executed using Amira 3D software.

RESULTS

All lesions were located at the level of the ventral brainstem. Specifically, one mesencephalic cavernoma, two pontine ca- vernomas, one pontine gliomas, and one medullary diffuse midline glioma were reported. Cerebrospinal fluid leak was the major complication that occurred in one case (medullary diffuse midline glioma). From an anatomical standpoint, three main safe entry zones were used, namely the anterior mesencephalic zone (AMZ), the peritrigeminal zone (PTZ, used in two cases), and the olivar zone (OZ). Reviewing the literature, 17 cases of various brainstem lesions treated using an EEA were found.

CONCLUSIONS

To our knowledge, this was the first preliminary clinical series of intrinsic brainstem lesions treated via an EEA presented in the literature. The EEA can be considered a valid surgical alternative to traditional transcranial approaches to treat selected intra-axial brainstem lesions located at the level of the ventral brainstem. To achieve good results, surgery must involve comprehensive anatomical knowledge, meticulous preoperative surgical planning, and intraoperative neurophysiological moni- toring.

Transclival approaches for intradural pathologies: historical overview and present scenario

Recently, endoscopic transsphenoidal transclival approaches have been developed and their role is widely accepted for extradural pathologies. Their application to intradural pathologies is still debated, but is undoubtedly increasing. In the past five decades, different authors have reported various extracranial, anterior transclival approaches for intradural pathologies. The aim of this review is to provide a historical overview of transclival approaches applied to intradural pathologies. PubMed was searched in October 2018 using the terms transcliv*, cliv* intradural, transsphenoidal transcliv*, transoral transcliv*, transcervical transcliv*, transsphenoidal brainstem, and transoral brainstem. Exclusion criteria included not reporting reconstruction technique, anatomical studies, reviews without new data, and transcranial approaches. Ninety-one studies were included in the systematic review. Since 1966, transcervical, transoral, transsphenoidal microsurgical, and, recently, endoscopic routes have been used as a corridor for transclival approaches to treat intradural pathologies. Each approach presents a curve that follows Scott's parabola, with evident phases of enthusiasm that quickly faded, possibly due to high post-operative CSF leak rates and other complications. It is evident that the introduction of the endoscope has led to a significant increase in reports of transclival approaches for intradural pathologies. Various reconstruction techniques and materials have been used, although rates of CSF leak remain relatively high. Transclival approaches for intradural pathologies have a long history. We are now in a new era of interest, but achieving effective dural and skull base reconstruction must still be definitively addressed, possibly with the use of newly available technologies.

Endoscopic endonasal approach for brainstem cavernous malformation

This 25-year-old woman presented after a second hemorrhage from a mesencephalic cavernous malformation. High-definition fiber tracking demonstrated lateral displacement of the corticospinal tracts, making a midline approach ideal. The lesion appeared to present to the third ventricle, but a transcallosal approach was abandoned due to the posterior third ventricular location and after FIESTA imaging revealed a superior and medial rim of normal parenchyma that would have to be transgressed to access the malformation. An endoscopic endonasal approach with interdural pituitary hemitransposition was performed. The interpeduncular cistern was accessed and the thalamoperforating arteries dissected to access the cavernous malformation that was completely removed in a piecemeal fashion. The patient’s preexisting internuclear ocular palsies and hemiparesis were slightly worsened after surgery as predicted by a drop in anterior tibialis motor evoked potentials. Postoperative MRI showed no infarct, and the hemiparesis was back to baseline at 1-month follow-up.

The video can be found here: https://youtu.be/e6203R9HHmk.