Suprachiasmatic translamina terminalis corridor used in endoscopic endonasal approach for resecting third ventricular craniopharyngioma

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 cm3, 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.

Impact of three surgical approaches on the therapeutic efficacy of intraventricular craniopharyngiomas: a single-center retrospective analysis

This study aimed to investigate the therapeutic efficacy of three different surgical approaches for the treatment of intraventricular craniopharyngiomas (IVCs). The three surgical approaches investigated in this study were the endoscopic endonasal approach (EEA), pterional trans-lamina terminalis approach (PTA), and interhemispheric trans-lamina terminalis approach (ITA). Patient demographics, preoperative symptoms, endocrine and hypothalamic status, tumor characteristics, and surgical outcomes were analyzed and compared among the different surgical groups. A total of 31 patients with IVCs were included in the analysis, with 12 patients in the EEA group, 8 patients in the ITA group, and 11 patients in the PTA group. The mean follow-up time was 39 ± 23 months. Statistical analysis of the data revealed significant differences in the gross total resection (GTR) rate among the three surgical groups (P = 0.033). The GTR rate for the EEA group was 100%, that for the ITA group was 88%, and that for the PTA group was 64%, which was the lowest rate observed. After surgery, only 8.3% of the patients in the EEA group did not experience new postoperative hypopituitarism, while the percentages in the ITA and PTA groups were 75% and 73%, respectively (P = 0.012). Finally, we found that postoperative hypopituitarism may be related to the transection of the pituitary stalk during the operation (P = 0.020). Based on the results of this study, we recommend using the EEA and the ITA instead of the PTA for the surgical resection of IVCs. Furthermore, the appropriate surgical approach should be selected based on the tumor's growth pattern.

Duct-like Recess in the Infundibular Portion of Third Ventricle Craniopharyngiomas: An MRI Sign Identifying the Papillary Type

BACKGROUND AND PURPOSE

Papillary craniopharyngiomas (PCPs) are particularly challenging lesions requiring accurate diagnosis to plan the best therapy. Our aim was to define a narrow duct-like recess identified on MR imaging at the base of papillary craniopharyngiomas with a strict third ventricle location.

MATERIALS AND METHODS

A duct-like recess at the infundibular portion of craniopharyngiomas was observed on conventional T1WI and T2WI in 3 strict third ventricle papillary craniopharyngiomas in our craniopharyngioma series (n = 125). We systematically investigated this finding on the MR imaging of 2582 craniopharyngiomas and 10 other categories of third ventricle tumors (n = 690) published in the modern era (1986-2020). The diagnostic value and significance of this finding are addressed.

RESULTS

The duct-like recess was recognized in 52 papillary craniopharyngiomas, including 3 of our own cases, as a narrow canal-shaped cavity invaginated at the tumor undersurface, just behind the optic chiasm. This structure largely involves papillary craniopharyngiomas with a strict third ventricle topography (96%), follows the same diagonal trajectory as the pituitary stalk, and finishes at a closed end. The duct-like recess sign identifies the papillary craniopharyngioma type with a specificity of 100% and a sensitivity of 38% in the overall craniopharyngioma population. This finding can also establish the strictly intra-third ventricle location of the lesion with a 90% specificity and 33% sensitivity. These recesses appear as hypointense circular spots on axial/coronal T1WI and T2WI. Their content apparently corresponds to CSF freely flowing within the suprasellar cistern.

CONCLUSIONS

The presence of a duct-like recess at the infundibular portion of a third ventricle tumor represents a distinctive hallmark of papillary craniopharyngiomas that can be used as a simple MR imaging sign to reliably diagnose these lesions.

Duct-like diverticulum at the base of third ventricle tumors: a morphological signature diagnostic of papillary craniopharyngioma

This study describes and characterizes a narrow, hollow tubular structure, termed as duct-like diverticulum (DV), found specifically at the basal midline of papillary craniopharyngiomas (PCPs) located within the third ventricle (3V). The presence of this structure was systematically investigated on autopsy studies and magnetic resonance imaging (MRI) scans of 3536 craniopharyngioma (CP) cases published in the medical literature from 1911 to 2021, as well as in other twelve 3V tumor categories (n = 1470 cases). A basal DV was observed in a total of 50 PCPs, including two of our own cases. This DV corresponds to a tubular-shaped recess invaginated at the midline bottom of the tumor, following the same angled trajectory as the pituitary stalk. It can be easily seen as a hypointense linear structure on T1- and T2-weighted MRI scans, with two main length types: long DVs (74%), which reach the tumor center, and short DVs (26%), which penetrate the tumor only a few millimeters. The DV sign identifies the papillary CP type with a specificity of 100% and a sensitivity of 33% in the overall CP population. This finding also serves to establish the strictly intra-3V location of the lesion with a 95% specificity and 42% sensitivity among papillary CPs. No similar basal DV was found in adamantinomatous CPs nor among other categories of strictly 3V tumors. Consequently, the presence of a diverticulum in a 3V tumor represents a morphological signature pathognomonic of the papillary type and a valuable sign to reliably define the strictly 3V topography.

Feasibility of endoscopic endonasal resection of intrinsic third ventricular craniopharyngioma in adults

Intrinsic third ventricular craniopharyngiomas (IVCs) are usually considered as a contraindication of endoscopic endonasal approach (EEA). The aim of this study is to evaluate the safety and feasibility of EEA for the resection of IVCs based on MRI topographical diagnosis and surgical findings. We reviewed the data of 22 patients who were diagnosed to be IVCs according to five MRI criteria and underwent surgery through EEA. Sixteen IVCs were resected using endoscopic endonasal infrachiasmatic corridor, five IVCs by using endoscopic endonasal suprachiasmatic trans-lamina terminalis corridor, and one IVC by using both the infrachiasmatic and suprachiasmatic corridors. During the operation, all the 22 cases were verified to be IVCs. Gross total resection was achieved in 21 (95.5%) patients. After surgery, visual improvement was observed in 14 (63.6%) patients, no change in 6 (27.3%) patients, and some deterioration in 2 (9.1%) patients. An improvement in intellectual ability was observed in nine (40.9%) patients, no change in twelve (54.5%) patients, and some deterioration in one (4.5%) patient. Fifteen of the 22 patients (68.2%) developed new endocrinological deficit. One postoperative cerebral spinal fluid leakage occurred. EEA can be used as a safe and efficacious approach for the radical resection of IVCs. The combination of the five MRI criteria may serve as an accurate preoperative diagnostic tool to define the topographical relationships between craniopharyngiomas and the third ventricle. The endoscopic transnasal view from below has the advantage of clarifying the relationship between tumors and the third ventricle floor.

Endoscopic endonasal surgical anatomy through the prechiasmatic sulcus: the key window to suprachiasmatic and infrachiasmatic corridors

BACKGROUND

Classically, the transtuberculum and transplanum approaches have been utilized to reach the suprachiasmatic and infrachiasmatic corridors. The aim of this study was to provide a better understanding of the key endoscopic endonasal anatomy of the suprachiasmatic and infrachiasmatic corridors provided through selective removal of the prechiasmatic sulcus (SRPS).

METHOD

A SRPS was performed in 16 sides of 8 alcohol-fixed head specimens. Twenty anatomical measurements were collected on the suprachiasmatic and infrachiasmatic corridors. The transplanum and transtuberculum approaches were also performed.

RESULTS

In the suprachiasmatic corridor, the SRPS exposed the anterior communicating artery (AComm) and the post-communicating segment of the anterior cerebral arteries in all the cases, while the pre-communicating segment of the anterior cerebral arteries, recurrent arteries of Heubner, and fronto-orbital arteries were visualized in 75% (12/16), 31% (5/16), and 69% (11/16) of cases, respectively. In the infrachiasmatic corridor, the ophthalmic segment of the internal carotid artery and superior hypophyseal arteries were always visible through the SRPS. The mean width and height of the prechiasmatic sulcus were 13.2 mm and 9.6 mm, respectively. The mean distances from the midpoint of the AComm to the anterior margin of the optic chiasm (OCh) was 5.3 mm. The mean width of the infrachiasmatic corridor was 12.3 mm at the level of the proximal margin of the ophthalmic segment of the internal carotid artery. The mean distances from the posterior superior limit of the pituitary stalk to the basilar tip and oculomotor nerve were 9.7 mm and 12.3 mm, respectively.

CONCLUSIONS

The SRPS provides access to the main neurovascular and cisternal surgical landmarks of the suprachiasmatic and infrachiasmatic corridors. This anatomical area constitutes the key part of the approach to the suprasellar area. To afford adequate surgical maneuverability, the transplanum or transtuberculum approaches are usually a necessary extension.

Expanded Transsphenoidal Trans-Lamina Terminalis Approach to Tumors Extending Into the Third Ventricle: Technique Notes and a Single Institute Experience

Object

The trans lamina terminalis approach (TLTA) has been described as a way to remove third ventricular tumors. The aim of this paper was to analyze the feasible outcomes of TLTA applied to tumors extending into the third ventricle in our institute.

Methods

Suprasellar tumors (n = 149) were treated by the extended endonasal approach from September 2019 to December 2020 in Beijing Tiantan Hospital. Eleven of the tumors were treated by TLTA or TLTA via the trans-chiasm-pituitary corridor (TCPC). The surgical technique notes of TLTA were described and indications and outcomes of the approach were analyzed.

Results

There were 11 patients enrolled in the study, six with papillary craniopharyngiomas, two with adamantinomatous craniopharyngiomas, one with a germinal cell tumor (GCT), one with cavernous malformation and one with chordoid glioma. Four of the patients received a radical resection by TLTA alone, while seven of them received TLTA via the TCPC. Gross total resection was achieved in eight patients (72.7%), and partial resection in three patients (27.3%). Visual function was improved in four of the 11 patients (36.4%), was unchanged in five patients (45.5%), and deteriorated in two patients (18.2%). New-onset hypopituitarism occurred in seven patients (63.3%) and new-onset diabetes insipidus occurred in two patients (18.2%). Electrocyte imbalance were observed in six patients (54.5%) at post-operative week 2. There were no surgery-related deaths or cerebrospinal fluid leaks. Postoperative intracranial infection was observed in one patient (9.1%), and during the follow-up period, tumor recurrence occurred in one patient (9.1%).

Conclusion

The expanded TLTA provides a feasible suprachiasm corridor to remove tumors extending into the third ventricle, especially for craniopharyngiomas. Sound understanding of the major strengths and limitations of this approach, as well as strategies for complication avoidance, is necessary for its safe and effective application.

Neuroendoscopic Transventricular Approach for Cystic Craniopharyngioma

The literature is rich with many studies reporting different treatment modalities and approaches for cystic craniopharyngioma (CC), including microsurgery, neuroendoscopic transventricular approach, endoscopic transnasal surgery, stereotactic drainage, and Ommaya reservoir insertion. The goals of this manuscript are to report the successful treatment of an atypical case of CC using the neuroendoscopic transventricular approach (NTVA) as well as discuss the different surgical modalities for these tumors following a comprehensive review of the literature. Our patient is a nine-year-old female with a large CC who was managed using the NTVA. No complications or recurrence occurred over two years of follow-up. Results of our literature review showed lower recurrence and complication rates of the NTVA compared to other surgical modalities.The NTVA is potentially efficient, reliable, and safe for managing CC and cystic-dominant craniopharyngiomas, with low recurrence and complication rates compared to microsurgery and Ommaya reservoir insertion. Future randomized clinical studies comparing the various treatment modalities of CC are needed to solidify these conclusions.

Strictly third ventricle craniopharyngiomas: pathological verification, anatomo-clinical characterization and surgical results from a comprehensive overview of 245 cases

The strictly third ventricle craniopharyngioma topography (strictly 3V CP) defines the subgroup of lesions developed above an anatomically intact third ventricle floor (3VF). The true existence of this exceedingly rare topographical category is highly controversial owing to the presumed embryological CP origin from Rathke's pouch, a structure developmentally situated outside the neural tube. This study thoroughly analyzes the largest series of strictly 3V CPs ever collected. From 5346 CP reports published between 1887 and 2021, we selected 245 cases with reliable pathological, surgical, and/or neuroradiological verification of an intact 3VF beneath the tumor. This specific topography occurs predominantly in adult (92.6%), male (64.4%) patients presenting with headache (69.2%), and psychiatric disturbances (59.2%). Neuroradiological features defining strictly 3V CPs are a tumor-free chiasmatic cistern (95.9%), an entirely visible pituitary stalk (86.4%), and the hypothalamus positioned around the tumor's lower pole (92.6%). Most are squamous papillary (82%), showing low-risk severity adhesions to the hypothalamus (74.2%). The adamantinomatous variant, however, associates a higher risk of severe hypothalamic adhesion (p < .001). High-risk attachments are also associated with psychiatric symptoms (p = .013), which represented the major predictor for unfavorable prognoses (83.3% correctly predicted) among cases operated from 2006 onwards. CP recurrence is associated with infundibulo-tuberal symptoms (p = .036) and incomplete surgical removal (p = .02). The exclusive demographic, clinico-pathological and neuroradiological characteristics of strictly 3V CPs make them a separate, unique topographical category. Accurately distinguishing strictly 3V CPs preoperatively from those tumors replacing the infundibulum and/or tuber cinereum (infundibulo-tuberal or not strictly 3V CPs) is critical for proper, judicious surgical planning.

Outcomes of the endoscopic endonasal approach for tumors in the third ventricle or invading the third ventricle

We aimed to retrospectively analyze the surgical and clinical outcomes of the endoscopic endonasal approach (EEA) for tumors in the third ventricle or invading the third ventricle. In total, 82 patients who had undergone surgical treatment using the EEA for tumors involving the third ventricle were enrolled in this study. This cohort study comprised 46 male and 36 female patients. The median age was 37 years (range, 5-76), and the median follow-up duration was 56.5 months (range, 6-117). Seventy-six patients had craniopharyngiomas, and 6 had gangliocytomas, gangliogliomas, astrocytomas, diffuse midline gliomas and lymphomas. Gross total removal was performed in 71 (86.5%) of the 82 patients, subtotal tumor removal in 7 patients and partial removal or biopsy in 4 patients. The pituitary stalk was preserved in 20 cases. Visual function improved in 40 (81.6%) of 49 patients. Endocrine function worsened in 41 (50%) of 82 patients. Hypothalamic function improved in 16 (72.7%) of 22 cases. Postoperative obesity occurred in 3 (20.0%) of 15 children and 11 (23.9%) of 46 adult patients. The postoperative cerebrospinal fluid leakage rate was 3.6%. Postoperative meningitis occurred in 18 (21.9%) cases. Permanent diabetes insipidus was identified in 73 (89.0%) of 82 patients. Tumor recurrence was observed in 10 patients (12%). The EEA appears to be a safe and effective treatment modality for tumors in the third ventricle or involving the third ventricle. However, more cases and long-term follow-up outcomes are required to confirm the clinical efficacy of the EEA.

Clinical features and operative technique of transinfundibular craniopharyngioma

OBJECTIVE

Transinfundibular craniopharyngioma (TC) is one of the 4 subtypes of suprasellar craniopharyngioma. In this study, the authors analyzed the clinical features of and operative technique for TC.

METHODS

A total of 95 consecutive cases of suprasellar craniopharyngioma that had been resected via the endoscopic expanded endonasal approach were retrospectively reviewed. Patients were divided into 2 groups: 34 in the TC group and 61 in the nontransinfundibular craniopharyngioma (NC) group. Clinical and radiographic features, intraoperative findings, histopathological and genetic findings, and surgical outcomes were analyzed and compared between groups.

RESULTS

Compared with NC, TC was mostly seen in adult patients (97.1%); it was rare in children (2.9%). Clinical presentations tended toward headache, hydrocephalus, and diabetes insipidus. The relatively smaller volume, midline location (consistent with the stalk position), unidentifiable stalk, no shift of the third ventricle, and greater likelihood to involve the third ventricle and cause hydrocephalus were the characteristic features of TC in the preoperative MRI study. According to the degree of vertical extension of the tumor, the 34 TCs could be classified into 3 subtypes: type 1, entity was limited to stalk (n = 2, 5.9%); type 2, tumor extended up to the third ventricle (type 2a) or down to the subdiaphragmatic cavity (type 2b) (n = 23, 67.6%); and type 3, tumor extended in both directions (n = 9, 26.5%). For TC resection, the chiasm-pituitary corridor, lamina terminalis corridor, and pituitary corridor could be used separately or jointly. Most of the TCs originated from the infundibulum-tuber cinereum, grew within and along the long axis of the infundibulum, and the pituitary stalk was not usually preserved in TCs (20.6%), whereas the rate of preservation was higher (80.3%) in NCs. Bilateral hypothalamic injury was found in nearly all TCs if radical resection was performed, whereas the relationship between NCs and hypothalamus was either compression (32.8%) or unilateral invasion (67.2%). Meanwhile, the postoperative endocrine and neuropsychological function outcomes in patients with TC were worse than in patients with NC. The genetic analysis with whole-exome sequencing studies showed no differential mutations of CTNNB1 (β-catenin) and BRAF (V600E) between TC and NC subtypes, but there was a difference between adamantinomatous craniopharyngioma and papillary craniopharyngioma.

CONCLUSIONS

TC is a special subtype of suprasellar craniopharyngioma, which is remarkably different from NC. Identification of this type of tumor preoperatively is essential for the planning of appropriate surgical approach and degree of excision.

Endonasal endoscopic transsphenoidal resection of intrinsic third ventricular craniopharyngioma: surgical results

OBJECTIVE

Intrinsic third ventricular craniopharyngiomas (IVCs) have been reported by some authors to "pose the greatest surgical challenge" of all craniopharyngiomas (CPAs). A variety of open microsurgical approaches have historically been used for resection of these tumors. Despite increased utilization of the endoscopic endonasal approach (EEA) for resection of CPAs in recent years, many authors continue to recommend against use of the EEA for resection of IVCs. In this paper, the authors present the largest series to date utilizing the EEA to remove IVCs.

METHODS

The authors reviewed a prospectively acquired database of the EEA for resection of IVCs over 14 years at Weill Cornell Medical College, NewYork-Presbyterian Hospital. Preoperative MR images were examined independently by two neurosurgeons and a neuroradiologist to identify IVCs. Pre- and postoperative endocrinological, ophthalmological, radiographic, and other morbidities were determined from retrospective chart review and volumetric radiographic analysis.

RESULTS

Between January 2006 and August 2017, 10 patients (4 men, 6 women) ranging in age from 26 to 67 years old, underwent resection of an IVC utilizing the EEA. Preoperative endocrinopathy was present in 70% and visual deterioration in 60%. Gross-total resection (GTR) was achieved in 9 (90%) of 10 patients, with achievement of near-total (98%) resection in the remaining patient. Pathology was papillary in 30%. Closure incorporated a "gasket-seal" technique with nasoseptal flap coverage and either lumbar drainage (9 patients) or a ventricular drain (1 patient). Postoperatively, complete anterior and posterior pituitary insufficiency was present in 90% and 70% of patients, respectively. In 4 patients with normal vision prior to surgery, 3 had stable vision following tumor resection. One patient noted a new, incongruous, left inferior homonymous quadrantanopsia postoperatively. In the 6 patients who presented with compromised vision, 2 reported stable vision following surgery. Each of the remaining 4 patients noted significant improvement in vision after tumor resection, with complete restoration of normal vision in 1 patient. Aside from the single case (10%) of visual deterioration referenced above, there were no instances of postoperative neurological decline. Postoperative CSF leakage occurred in 1 morbidly obese patient who required reoperation for revision of closure. After a mean follow-up of 46.8 months (range 4-131 months), tumor recurrence was observed in 2 patients (20%), one of whom was treated with radiation and the other with chemotherapy. Both of these patients had previously undergone GTR of the IVC.

CONCLUSIONS

The 10 patients described in this report represent the largest number of patients with IVC treated using EEA for resection to date. EEA for resection of IVC is a safe and efficacious operative strategy that should be considered a surgical option in the treatment of this challenging subset of tumors.

Is Low-Lying Optic Chiasm an Obstacle to an Endoscopic Endonasal Approach for Retrochiasmatic Craniopharyngiomas? (Korean Society of Endoscopic Neurosurgery -003)

OBJECTIVE

Despite advances in endoscopic techniques, retrochiasmatic craniopharyngiomas (CPs) are difficult to remove completely, because the low-lying optic chiasm often provides an obstacle to an endoscopic endonasal approach. This study aimed to identify the endoscopic surgical outcomes of the retrochiasmatic CP and resolve the issues related to low-lying optic chiasm.

METHODS

We reviewed 154 consecutive patients with CP who underwent endonasal endoscopic resection from February 2009 to April 2017 at 2 independent institutions. The topographic relationship of the tumor with the third ventricle, stalk, and optic chiasm and clinical outcomes were investigated.

RESULTS

Retrochiasmatic CPs were found in 142 of 154 patients (92.2%). The median follow-up time was 25 months. Gross total resection and near-total resection were achieved in 113 patients (79.6%) and 21 patients (13.8%), respectively. Postoperative cerebrospinal fluid leaks were found in 16 patients (11.3%). Low-lying and high-lying chiasms were found in 44 patients (31.0%) and 98 patients (69.0%), respectively. Low-lying chiasm did not affect clinical outcomes including the extent of resection. Patients with low-lying chiasm showed a marginal trend for postoperative visual deterioration. The ventricular growth pattern representing the origin of the tumor and previous surgery were significantly associated with the position of the optic chiasm (P = 0.007 and 0.001, respectively).

CONCLUSIONS

An endoscopic endonasal approach is an effective surgical approach for retrochiasmatic CP, even in tumors with low-lying chiasm. However, a thorough and careful dissection is necessary to prevent visual deterioration.

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.

Learning curve for the endoscopic endonasal approach for suprasellar craniopharyngiomas

The endoscopic endonasal approach is considered an alternative minimally invasive approach for suprasellar craniopharyngiomas. However, the complicated surgical manipulations required by this approach have limited its application. We evaluate whether the approach features a learning curve. Thirty-three patients were retrospectively reviewed and grouped as early (17 patients) and late (16 patient) groups. The operation time, extent of removal, ophthalmology, endocrinology, reconstruction and modifications of standard technique were evaluated. Between the two groups, the operation time decreased from 201.1±105.3min in the early group to 107.6±90.0min in the late group (p<0.05). Regarding clinical outcomes, non-significantly increasing trends toward the rate of gross total resection, visual improvement and (from 76.5% to 87.5%, 73.3% to 93.3%), significantly decreasing trends toward the rate of tumor recurrence (from 23.5% to 0% p<0.05) and non-significantly decreasing trends toward the rate of hypopituitarism recovery (26.7% to 0%) were observed between the two groups. With respect to complications, non-statistically significant decreasing trends toward transient cranial nerve paralysis (from 5.9% to 0%) and non-statistically significant increasing trends toward rate of CSF leakage, meningitis and new hypothyroidism (from 11.8% to 25%, 11.8% to 31.3%, 0 to 3%) were observed. We identified a learning curve for the endoscopic endonasal approach for suprasellar craniopharyngiomas. The exact number of patients necessary to establish a significant improvement in the clinical outcomes and decrease in the complications warrants further investigation. The outcomes of tumor recurrence may be associated with duration of follow-up. The CSF leakage represented the most common complication.

First Application of 7-T Magnetic Resonance Imaging in Endoscopic Endonasal Surgery of Skull Base Tumors

BACKGROUND

Successful endoscopic endonasal surgery for the resection of skull base tumors is reliant on preoperative imaging to delineate pathology from the surrounding anatomy. The increased signal-to-noise ratio afforded by 7-T MRI can be used to increase spatial and contrast resolution, which may lend itself to improved imaging of the skull base. In this study, we apply a 7-T imaging protocol to patients with skull base tumors and compare the images with clinical standard of care.

METHODS

Images were acquired at 7 T on 11 patients with skull base lesions. Two neuroradiologists evaluated clinical 1.5-, 3-, and 7-T scans for detection of intracavernous cranial nerves and internal carotid artery (ICA) branches. Detection rates were compared. Images were used for surgical planning and uploaded to a neuronavigation platform and used to guide surgery.

RESULTS

Image analysis yielded improved detection rates of cranial nerves and ICA branches at 7 T. The 7-T images were successfully incorporated into preoperative planning and intraoperative neuronavigation.

CONCLUSIONS

Our study represents the first application of 7-T MRI to the full neurosurgical workflow for endoscopic endonasal surgery. We detected higher rates of cranial nerves and ICA branches at 7-T MRI compared with 3- and 1.5-T MRI, and found that integration of 7 T into surgical planning and guidance was feasible. These results suggest a potential for 7-T MRI to reduce surgical complications. Future studies comparing standardized 7-, 3-, and 1.5-T MRI protocols in a larger number of patients are warranted to determine the relative benefit of 7-T MRI for endonasal endoscopic surgical efficacy.

Pathological and Topographical Classification of Craniopharyngiomas: A Literature Review

Craniopharyngiomas (CPs) are clinically relevant tumors of the sellar region and are associated with high morbidity and occasional mortality. There are two different subtypes of CPs that differ clinically and pathologically: adamantinomatous CP and papillary CP. The differential diagnosis is still challenging even with developments in preoperative imaging as several tumors of the sellar/parasellar region share a continuum of clinical characteristics and imaging similarities. Several topographical classifications of CPs have been mentioned in literature, but to date, there has not been a consensus on a standard reference classification system and there is need to a develop such a model.

Endoscopic Endonasal Surgery for Purely Intrathird Ventricle Craniopharyngioma

BACKGROUND

Extended endoscopic transsphenoidal surgery (EETS) is a safe and effective treatment for many suprasellar craniopharyngiomas, including those with third-ventricle involvement. Craniopharyngioma entirely within the third ventricle (purely intraventricular type), however, is generally regarded unsuitable for treatment with EETS.

CASE DESCRIPTION

Three patients underwent total removal of a purely intraventricular craniopharyngioma with inferior extension via EETS by direct incision of the bulging, stretched ventricular floor and fine dissection from the ventricular wall. In 2 patients with an anteriorly displaced chiasm, the space between the chiasm and pituitary stalk created a wide corridor to the ventricle, whereas in the third case, in which the infrachiasmal space was somewhat narrowed, partial sacrifice of the pituitary gland was necessary to obtain sufficient space. Despite preservation of the stalk in 2 patients, hypopituitarism and diabetes insipidus developed after surgery. There was no other complication including obesity.

CONCLUSIONS

Selected patients with purely intraventricular craniopharyngioma can be treated effectively and safely with EETS. Those with inferior extension in the interpeduncular fossa and anterior displacement of the chiasm may be suitable candidates.