Neuroendoscopy via an Extremely Narrow Foramen of Monro: A Case Report

A preliminary study of the diagnostic efficacy and safety of the novel boring biopsy for brain lesions

Existing methods for biopsy of intraparenchymal brain lesions, including stereotactic biopsy and open block biopsy, have advantages and disadvantages. We propose a novel biopsy method, called “boring biopsy,” which aims to overcome the drawbacks of each conventional method. This method is less invasive and allows obtaining continuous specimens of sufficient volume. We aimed to assess the feasibility and efficacy of using boring biopsy for intraparenchymal brain lesions. We included 26 consecutive patients who underwent boring biopsy for intraparenchymal lesions. Columnar continuous specimens from the surface of the normal brain tissue to the tumor margin and the center of the lesion were obtained using the boring biopsy method. We used a catheter introducer with original modifications to create a cylindrical biopsy tool for surgery. Columnar continuous specimens were successfully obtained. Histopathological diagnosis was based on cellular changes and differentiation from normal tissues to the core of the lesion and established in all cases. No permanent deficits, major adverse outcomes, or deaths were observed. This novel technique may improve diagnostic accuracy and reduce invasiveness associated with brain biopsy. This method may become the next standard procedure, particularly in some cases where histological evaluation is paramount, and conventional biopsy methods are not suitable.

Multidisciplinary treatment of primary intracranial yolk sac tumor: A case report and literature review

RATIONALE

Intracranial yolk sac tumors (YSTs) are rare malignancies with limited treatment options and a dismal prognosis. They are usually managed with surgical resection and chemoradiotherapy.

PATIENT CONCERNS

Here, we report a patient with primary YST in the pineal region who achieved long term survival. Despite undergoing treatment, he experienced several recurrences over a 15-year period.

DIAGNOSIS

Brain magnetic resonance imaging (MRI) demonstrated the presence of space-occupying lesions in the pineal region and the medial tail of the left lateral ventricle. The tumors were excised, and the histological diagnosis suggested an intracranial YST.

INTERVENTIONS

The patient achieved long term survival after combined modality therapy including surgery, stereotactic radiosurgery (SRS)/intensity modulated radiation therapy (IMRT), chemotherapy, and targeted therapy.

OUTCOMES

The disease remained stable. However, the patient gave up treatment and passed away in October 2020, with a total survival of about 15 years.

LESSONS

To the best of our knowledge, this patient with intracranial YST had received a longer survival compared with other published reports. We summarize previously published reports of intracranial YST and discuss the importance of multidisciplinary treatment. SRS may have a role, as a focal boost to residual tumor after resection or in case of recurrence after conventional radiotherapy, in the multimodality management of intracranial YSTs.

A critical appraisal of Monro's erroneous description of the cerebral interventricular foramina: Age-related magnetic resonance imaging spatial morphometry and a proposed new terminology

Anatomic connections between the cerebral lateral and third ventricles have been mischaracterized since Monro's original erroneous description of his eponymous foramina (FoMs) as being only one T-shaped passage. Accurate knowledge of the in vivo three-dimensional (3D) configuration of FoM has important clinical neuroendoscopic, neurosurgical, and neuroimaging implications. We retrospectively analyzed volumetric high-resolution brain magnetic resonance imaging of 100 normal individuals to characterize the normal spatial anatomy and morphometry for each FoM. We measured the true anatomical 3D angulations of FoMs relative to standard neuroimaging orthogonal planes, and their minimum width, depth, and distance between the medial borders of bilateral FoMs. The right and left FoMs were separate, distinct, and in a V-shaped configuration. Each FoM was a round, oval, or crescent-shaped canal-like passage with well-defined borders formed by the semicircular concavity of the ipsilateral forniceal column. The plane of FoM was angled on average 56.8° ± 9.1° superiorly from the axial plane, 22.5° ± 10.7° laterally, and 37.0° ± 6.9° anteriorly from the midsagittal plane; all these angles changing significantly with increasing age. The mean narrowest diameter of FoM was 2.8 ± 1.2 mm, and its depth was 2.5 ± 0.2 mm. Thus, the true size and orientation of FoM differs from that depicted on standard neuroimaging. Notably, in young subjects, FoM has a diameter smaller than its depth, a configuration akin to a short, small canal. We propose that the eponym "Monro" no longer be associated with this structure, and the term "foramen" be abandoned. Instead, FoM should be more appropriately renamed as the "interventricular canaliculus," or IVC, for short.

Cyst fenestration and Ommaya reservoir placement in endoscopic transcortical transventricular approach for recurrent suprasellar cystic craniopharyngioma without ventriculomegaly

The efficacy of the endoscopic transcortical transventricular approach (ETTA) for craniopharyngioma in the third ventricle with hydrocephalus has been reported focusing on its reduced invasiveness. On the other hand, suprasellar craniopharyngioma without ventriculomegaly is generally surgically managed by craniotomy or the endoscopic endonasal approach (EEA). Here, we report an elderly patient who received cyst fenestration and Ommaya reservoir placement in ETTA for recurrent suprasellar cystic craniopharyngioma without ventriculomegaly. The ETTA as a less invasive procedure is feasible in patients not only with intraventricular craniopharyngioma but also with suprasellar craniopharyngioma without hydrocephalus provided a navigational system is applied and the surgeon has ample experience with transcranial endoscopic procedures.

Watertight Robust Osteoconductive Barrier for Complex Skull Base Reconstruction: An Expanded-endoscopic Endonasal Experimental Study

Endoscopic skull base reconstruction (ESBR) following expanded-endoscopic endonasal approaches (EEA) in high-risk non-ideal endoscopic reconstructive candidates remains extremely challenging, and further innovations are still necessary. Here, the aim is to study the reconstructive knowledge gap following expanded-EEA and to introduce the watertight robust osteoconductive (WRO)-barrier as an alternative durable option. Distinctively, we focused on 10 clinical circumstances. A 3D-skull base-water system model was innovated to investigate the ESBR under realistic conditions. A large-irregular defect (31 × 89 mm) extending from the crista galli to the mid-clivus was achieved. Then, WRO-barrier was fashioned and its tolerance was evaluated under stressful settings, including an exceedingly high (55 cmH₂O) pressure, with radiological assessment. Next, the whole WRO-barrier was drilled to examine its practical-safe removal (simulating redo-EEA) and the whole experiment was repeated. Finally, WRO-barrier was kept into place to value its 18-month long-term high-tolerance. Results in all experiments of WRO-barriers were satisfactorily fashioned to conform the geometry of the created defect under realistic circumstances via EEA, tolerated an exceedingly high pressure without evidence of leak even under stressful settings, resisted sudden-elevated pressure, and remained in its position to maintain long-term watertight seal (18 months), efficiently evaluated with neuroimaging and simply removed-and-reconstructed when redo-EEA is needed. In conclusion, WRO-barrier as an osteoconductive watertight robust design for cranial base reconstruction possesses several distinct qualities that might be beneficial for patients with complex skull base tumours.

Risks of Endoscopic Temporal Ventriculocisternostomy for Isolated Lateral Ventricle: Anatomic Surgical Nuances

BACKGROUND

Entrapment of the temporal horn, known as isolated lateral ventricle (ILV), is a rare type of noncommunicating focal hydrocephalus, and standard treatment has not been established. We report 2 cases of endoscopic surgery for ILV and highlight the anatomic surgical nuances to avoid associated surgical risks.

CASE DESCRIPTION

The first patient presented with recurrent ILV following initial shunt placement for ILV, owing to shunt malfunction. In the second patient, ILV recurred secondary to choroid plexus inflammation caused by cryptococcal infection. Endoscopic temporal ventriculocisternostomy was effective in both cases. However, in the second case, the choroidal fissure was fenestrated, which led to cerebral infarction in the territory of the choroidal artery zone, attributed to damage of the branches of the choroidal segment of the anterior choroidal artery.

CONCLUSIONS

Although endoscopic temporal ventriculocisternostomy is considered a safe and less invasive procedure for treatment of symptomatic ILV, the technique is still associated with risks. To avoid complications, it is necessary to be familiar with the anatomy of the choroidal arteries and the pertinent endoscopic intraventricular orientation. Additionally, sufficient experience is required before it can be recommended as the treatment of choice.

Management of hypertrophied dural lesions: Is surgery a better option?

It is often difficult to definitively diagnose dural lesions with hypertrophy as they exhibit nonspecific imaging findings and clinical symptoms. Most cases require histopathological evaluation with surgical intervention (such as biopsy). However, complications related to surgical interventions remain as matter of concern. Herein, we analyzed and verified the significance of surgery in 39 patients with hypertrophic dural lesions who were histopathologically diagnosed with surgical interventions. Specimens of dural lesions were obtained successfully, and it was possible to make a definitive diagnosis for each case based on histopathological findings. All patients tolerate the procedures well, and there were no evidences of surgery-related complications during surgical approach to the dura mater. Preoperative and pathological diagnoses varied in eight cases. Our results indicate that histopathological evaluation is important for distinguishing diseases showing dural hypertrophy even if surgical invasiveness is concerned. Neurosurgeons should not hesitate to perform surgery for management of dural lesions with hypertrophy in order to achieve accurate diagnosis.