The transventricular preforniceal approach for exophytic chiasmatic/hypothalamic astrocytomas extending into the anterior third ventricle

Quantitative analysis of exposure and surgical maneuverability of three purely endoscopic keyhole approaches to the floor of the third ventricle

BACKGROUND

The quantitative anatomic analysis of comprehensively endoscopic approaches to the third ventricle is scarce at present. The objective of the study is to quantitatively assess and compare the exposure and microsurgical maneuverability of three absolutely endoscopic keyhole approaches, including interhemispheric transcallosal transchoroidal (TCTC), frontal transforminal transchoroidal (TFTC) and supraorbital subfrontal translamina terminalis (SFTL) approaches.

METHODS

Anatomical dissections and exposure of the important structures of the third ventricle were performed using six formalin-fixed cadaveric human heads (twelve sides) under endoscope. Tubular retractor system was used in the TFTC approach. Quantitative anatomical relationship between the important landmarks were obtained. Moreover, the exposure and surgical operability of three approaches were evaluated through applying the rating scale and accomplishing the quantitative anatomic analysis, area of surgical freedom and angle of attack.

RESULTS

The mediolateral, anteroposterior (AM: between aqueduct and mammillary body; IM: between infundibular recess and mammillary body) and superoinferior distance of TCTC, TFTC and SFTL approaches were 4.0±1.0, 4.2±0.4, 4.1±1.1 mm; 17.3±1.4, 17.6±0.5, 12.8±3.3 mm (AM); 7.7±0.3, 7.8±0.5 mm, not measured (IM); and 5.6±0.3, 7.8±0.8, 7.8±1.5 mm, respectively. Similar to TFTC, the exposed landmarks of TCTC were almost scored a "4" by three neurosurgeons except the infundibular recess scored a "3" according to the rating scale. During the SFTL approach, apart from the roof, the majority of the landmarks were scored a "4" except for the infundibular recess, which was scored a "3." The mean area of surgical freedom of TCTC (0° endoscope: 220±47; 30°: 247±56 mm2) was not significantly different from that of TFTC approach (0° endoscope: 216±49; 30°: 245±53 mm2) under same endoscope, P>0.05. Mean angle of attack of TCTC (0° endoscope: 21±4°; 30°: 26±4°) was significantly larger than that of TFTC approach (0° endoscope: 16±3°; 30°: 19±3°), P<0.05.

CONCLUSIONS

Purely endoscopic TCTC and TFTC approaches offer brilliant exposure of the anterior, middle and posterior third ventricle. TCTC approach may have better surgical maneuverability than TFTC approach. Despite the long working distance, the whole third ventricle are exposed well except for the roof in the SFTL approach, and surgical manipulation can be accomplished smoothly.

Contralateral Anterior Interhemispheric–Transcallosal–Transrostral Approach for the Resection of a Subcallosal Cavernous Malformation: A Case Report and an Operative Video

This case report demonstrates the surgical resection of a cerebral cavernous malformation located in the subcallosal region. The authors present a detailed operative video explaining the steps to successfully remove the lesion through a contralateral interhemispheric–transcallosal–transrostral approach with the patient in lateral decubitus. The surgical procedure was uneventful, and the patient had no postoperative deficits and no residual lesions in a three-month follow-up.

Transventricular Preforniceal Approach Combined with Endoscopic Transnasal Surgery for a Giant Pituitary Adenoma: A Case Report and Literature Review

Giant pituitary adenomas carry significant surgical risks when treated with transsphenoidal approaches or the transcranial approach alone. Combined transsphenoidal and transcranial approaches have been reported; however, removing adenomas extending into the third ventricle may still be challenging. We report a case of giant pituitary adenoma expanding into the third ventricle, which was removed using a combined transventricular preforniceal approach and an endoscopic endonasal transsphenoidal surgery (ETSS). A 41-year-old man with headache, nausea, and a 1-week history of a visual field defect was transferred to our hospital. He had a disturbed left visual acuity, right homonymous hemianopia, and choked disc in both eyes. Preoperative magnetic resonance imaging revealed a giant pituitary adenoma with a maximum diameter of 55 mm extending from the intrasellar to the suprasellar region, thus occupying the entire third ventricle and causing hydrocephalus. The space between the anterior commissure and the fornix was expanded. The foramen of Monro was shifted backward due to compression by the tumor. He underwent maximum surgical resection using a combined transventricular preforniceal approach and ETSS. Considering technical demands and reliability, the intra- to suprasellar parts were removed by ETSS while the intraventricular part was removed through the preforniceal approach. The residual tumor in the right cavernous sinus and behind the anterior communicating artery was treated with stereotactic radiotherapy. One year after the operation, the patient leads an independent life. The combined technique of the preforniceal approach and ETSS provided a direct view of the entire third ventricle and hemostasis in the present case.

Quantitative Anatomic Analysis of the Transcallosal-Transchoroidal Approach and the Transcallosal-Subchoroidal Approach to the Floor of the Third Ventricle: An Anatomic Study

OBJECTIVE

To compare transcallosal-transchoroidal and transcallosal-subchoroidal approaches to the ipsilateral and contralateral edges of the floor of the third ventricle using quantitative analyses.

METHODS

Five formalin-fixed cadaveric human heads (10 sides) were examined under the operating microscope. Quantitative measurements (area of surgical freedom and angle of attack) were obtained using 3-T magnetic resonance imaging and a StealthStation image guidance system. The limits of the surgical approaches were shown by touching a probe to 6 designated points on the floor of the third ventricle.

RESULTS

The transchoroidal approach provided greater surgical freedom than the subchoroidal approach to access ipsilateral and contralateral middle landmarks at the edges of the floor of the third ventricle in both longitudinal and horizontal planes (P ≤ 0.03). No significant difference between the 2 approaches was found in accessing the anterior and posterior landmarks of the third ventricle in each plane. The surgical freedom to the contralateral anterior, middle, and posterior landmarks was greater than to the ipsilateral landmarks in both the transchoroidal and subchoroidal approaches.

CONCLUSIONS

The transcallosal-transchoroidal approach, compared with the transcallosal-subchoroidal approach, may provide better exposure and require less retraction for removal of ipsilateral or contralateral lesions located in the midbrain or hypothalamus and situated near the floor of the third ventricle. The contralateral transcallosal approach with either the transchoroidal or subchoroidal approach may provide good surgical freedom for removal of lesions located near the floor of the third ventricle, such as lesions in the midbrain.

Pediatric Optic Pathway/Hypothalamic Glioma

Optic pathway/hypothalamic gliomas (OP/HGs) are rare astrocytic tumors that appear more commonly among young children and often are unresectable. They comprise approximately 2% of all central nervous system tumors and account for 3–5% of pediatric intracranial tumors. Initial manifestations are often visual disturbances, endocrinopathies and hypothalamic dysfunction such as the diencephalic syndrome, and sometimes hydrocephalus due to cerebrospinal fluid (CSF) outflow obstruction. In many cases, the tumors are diagnosed late in the clinical course because they silently enlarge. These tumors consist mostly of histologically benign, World Health Organization (WHO) grade I tumors represented by pilocytic astrocytomas (PA), the rest being pilomyxoid astrocytomas (PXA) – WHO grade II tumors. In young pediatric patients, however, can be seen PXA that show aggressive clinical course such as CSF dissemination. Our small series of 14 non-Neurofibromatosis type 1 (NF-1) OP/HGs PA patients underwent extended resection without any adjuvant treatments. The median age at initial treatment was 11.5 ± 6.90 years (range, 1–25 years) and median follow up 85.5 ± 25.0 months. Surgical resection for OP/HGs results in acceptable middle-term survival, tumor control and functional outcome equivalent to chemotherapy. There is, however, no longer doubt that chemotherapy with or without biopsy and as-needed debulking surgery remains the golden standard in management of OP/H. Clinical conditions and treatment plans for OP/HGs vary depending on their structure of origin.

Contralateral anterior interhemispheric-transcallosal-transrostral approach to the subcallosal region: a novel surgical technique

OBJECTIVE The authors report a novel surgical route from a superior anatomical aspect-the contralateral anterior interhemispheric-transcallosal-transrostral approach-to a lesion located in the subcallosal region. The neurosurgical approach to the subcallosal region is challenging due to its deep location and close relationship with important vascular structures. Anterior and inferior routes to the subcallosal region have been described but risk damaging the branches of the anterior cerebral artery. METHODS Three formalin-fixed and silicone-injected adult cadaveric heads were studied to demonstrate the relationships between the transventricular surgical approach and the subcallosal region. The surgical, clinical, and radiological history of a 39-year-old man with a subcallosal cavernous malformation was retrospectively used to document the neurological examination and radiographic parameters of such a case. RESULTS The contralateral anterior interhemispheric-transcallosal-transrostral approach provides access to the subcallosal area that also includes the inferior portion of the pericallosal cistern, lamina terminalis cistern, the paraterminal and paraolfactory gyri, and the anterior surface of the optic chiasm. The approach avoids the neurocritical perforating branches of the anterior communicating artery. CONCLUSIONS The contralateral anterior interhemispheric-transcallosal-transrostral approach may be an alternative route to subcallosal area lesions, with less risk to the branches of the anterior cerebral artery, particularly the anterior communicating artery perforators.

Resection of tumors of the third ventricle involving the hypothalamus: effects on body mass index using a dedicated surgical approach

Resection of large lesions growing into the third ventricle is considered nowadays still a demanding surgery, due to the high risk of severe endocrine and neurological complications. Some neurosurgical approaches were considered in the past the procedures of choice to access the third ventricle, however they were burden by endocrine and neurological consequences, like memory loss and epilepsy. We report here the endocrine and functional results in a series of patients operated with a recently developed approach specifically tailored for the resection of large lesions growing into the third ventricle. Authors conducted a retrospective analysis on 10 patients, operated between 2011 and 2012, for the resection of large tumors growing into the third ventricle. Total resection was achieved in all patients. No perioperative deaths were recorded and all patients were alive after the follow-up. One year after surgery 8/10 patients had an excellent outcome with a Karnofsky Performance Status of 100 and a Glasgow Outcome score of 5, with 8 patients experiencing an improvement of the Body Mass Index. Modern neurosurgery allows a safe and effective treatment of large lesions growing into the third ventricle with a postoperative good functional status.

A flexible endoscope-assisted interhemispheric transcallosal approach through the contralateral ventricle for the removal of a third ventricle craniopharyngioma: A technical report

Background:

Intraventricular craniopharyngiomas are difficult to remove. We combined an interhemispheric transcallosal approach with a flexible endoscope (videoscope) for successful tumor removal.

Case Description:

A 52-year-old male complained of general fatigue and memory disturbance. Magnetic resonance imaging revealed a well-enhanced third ventricle mass with dilatation of lateral ventricles. During removal with the interhemispheric transcallosal approach, a videoscope that was inserted into the left lateral ventricle revealed the interface of the tumor and the ventricular wall. The tumor was pushed to the right using forceps and removed totally through the right foramen of Monro without any fornix injury.

Conclusion:

This procedure is a safe option for removing third ventricular tumors especially in the case with hydrocephalus.