Surgical Proposition of a Slow-Growing Calvarial Exostosis in a Female Patient With a Congenital Iris Cyst of the Anterior Chamber and Mandibular Tori

We present an unusual case of a woman in her early 50s with a slow-growing calvarial exostosis. Exostoses are bony spurs or osteomas extending outward beyond a bone's surface and may be benign or malignant. Calvarial exostoses are a less common bone tumor that can occur in the population. We present a case of a rare, slow-growing calvarial exostosis with a combination of mandibular tori and a congenital iris cyst. We discuss differentials of this exostosis and different syndromes that may cause it such as hereditary multiple exostoses and Gardner syndrome. The current article aims to spread awareness of this atypical presentation of exostoses and present our institution's surgical proposition for removing a calvarial exostosis to obtain a further histological analysis of its composition. As these masses may commonly be benign, a definitive diagnosis cannot be made through imaging alone to rule out more threatening conditions. We have addressed radiological findings and diagnostic and treatment options offered to the patient. The patient decided not to move forward with removing the mass and would continue to monitor and return should she notice any unusual or acute changes.

Postoperative mometasone irrigations improve quality of life in skull base tumor patients

Objectives

The use of topical corticosteroids to manage postoperative sinonasal symptoms after endoscopic skull base surgery (ESBS) has not been well studied. We quantified long-term impact of postoperative steroid irrigations (SIs) on quality of life of patients after ESBS.

Methods

Retrospective review of patients at the University of Pennsylvania undergoing ESBS from 2010 to 2019. Data on patient demographics and postoperative treatment with nasal saline irrigation twice daily with and without dissolved steroids (mometasone or budesonide) was collected. Preoperative, and 1-, 3-, 6-, 12-, 18-, and 24-month postoperative Sino-Nasal Outcome Test (SNOT-22) scores were assessed.

Results

A total of 727 patients were assessed (53.4% males), with 479 patients in the no SI group and 248 patients in the SI group. Preoperative SNOT-22 scores did not differ significantly (P = 0.19). 1-, 3-, 6-, 12-, 18-, and 24-month post-op SNOT-22 scores did not significantly differ between groups. However, mometasone irrigations resulted in significantly lower postoperative 2-year SNOT-22 scores compared to budesonide (P < 0.01) and saline (P = 0.03).

Conclusions

Though corticosteroid irrigations are routine in managing inflammatory sinus disease, their role in postoperative management after ESBS for tumors is unclear. Our findings suggest that mometasone irrigation may be effective at improving postoperative quality of life in patients after ESBS.

Impact of salvage surgery with or without reirradiation for skull base meningiomas recurring after prior radiotherapy

OBJECTIVE

Long-term follow-up of meningiomas has demonstrated recurrence rates ranging from 2.5% to 48% after 10 years, depending on histology grade. There are limited data available to guide the management of recurrent and previously irradiated skull base meningiomas, and challenges related to salvage surgery, reirradiation, and lack of clear systemic therapy strategies remain. In this study, the authors analyzed data from their experience with recurrent and previously irradiated meningiomas to assess the impact of salvage surgery and reirradiation on progression-free survival (PFS).

METHODS

A retrospective cohort study of 48 patients with recurrent and previously irradiated meningiomas who were treated between 1995 and 2021 was conducted. Data were extracted from medical records and included clinical, radiological, and pathologic reports. Patients were clustered according to WHO grades. The authors analyzed the complications related to reirradiation and salvage surgery and the impact of different treatment modalities on PFS using Cox proportional hazard ratios.

RESULTS

Forty-eight patients (33 with WHO grade I, 11 with WHO grade II, and 4 with WHO grade III meningiomas) were treated for 143 recurrences after their first radiation treatment. For WHO grade I meningiomas, there was no change in tumor control rates with adjuvant repeat radiotherapy (HR 0.784, 95% CI 0.349-1.759; p = 0.55), and in terms of extent of resection (EOR), subtotal resection (STR) alone was associated with an increased risk of recurrence when compared with gross-total resection (GTR) (HR 3.38, 95% CI 1.268-9.036; p = 0.0189). For WHO grade II meningiomas, GTR did not significantly confer improved tumor control relative to STR (HR 0.42, 95% CI 0.17-1.037; p = 0.055), but adjuvant repeat radiotherapy after STR was associated with improved outcomes (HR 0.316, 95% CI 0.13-0.768; p = 0.0029). Finally, for WHO grade III meningiomas, EOR did not correlate with outcomes (HR 0.75, 95% CI 0.22-2.482; p = 0.588), but repeat radiotherapy alone was associated with a decreased odds of progression (HR 0.276, 95% CI 0.078-0.97; p = 0.0028).

CONCLUSIONS

This study examined the impact of retreatment on PFS in a large cohort of patients with recurrent meningiomas that had been previously irradiated. At the time of recurrence, WHO grade I meningiomas exhibited improved PFS with GTR, subtotally resected WHO grade II meningiomas appeared to have improved PFS when reirradiated, and reirradiation in WHO grade III meningiomas showed improved PFS.

The role of particle radiotherapy in the treatment of skull base tumors

The skull base is an anatomically and functionally critical area surrounded by vital structures such as the brainstem, the spinal cord, blood vessels, and cranial nerves. Due to this complexity, management of skull base tumors requires a multidisciplinary approach involving a team of specialists such as neurosurgeons, otorhinolaryngologists, radiation oncologists, endocrinologists, and medical oncologists. In the case of pediatric patients, cancer management should be performed by a team of pediatric-trained specialists. Radiation therapy may be used alone or in combination with surgery to treat skull base tumors. There are two main types of radiation therapy: photon therapy and particle therapy. Particle radiotherapy uses charged particles (protons or carbon ions) that, due to their peculiar physical properties, permit precise targeting of the tumor with minimal healthy tissue exposure. These characteristics allow for minimizing the potential long-term effects of radiation exposure in terms of neurocognitive impairments, preserving quality of life, and reducing the risk of radio-induced cancer. For these reasons, in children, adolescents, and young adults, proton therapy should be an elective option when available. In radioresistant tumors such as chordomas and sarcomas and previously irradiated recurrent tumors, particle therapy permits the delivery of high biologically effective doses with low, or however acceptable, toxicity. Carbon ion therapy has peculiar and favorable radiobiological characteristics to overcome radioresistance features. In low-grade tumors, proton therapy should be considered in challenging cases due to tumor volume and involvement of critical neural structures. However, particle radiotherapy is still relatively new, and more research is needed to fully understand its effects. Additionally, the availability of particle therapy is limited as it requires specialized equipment and expertise. The purpose of this manuscript is to review the available literature regarding the role of particle radiotherapy in the treatment of skull base tumors.

Pituitary Teratoma: A Case Series of Three Cases

Mature cystic teratoma (MCT) is a benign germ cell tumor, histologically comprising components derived from mesoderm, ectoderm, and endoderm layer tissue. MCT usually has foci of intestinal components and colonic epithelia. Pituitary teratomas containing complete colon features are very rare. Here, we present three cases of sellar teratoma in two men aged 50 and 65 years and a woman aged 30 years. All patients presented with asthenia, adynamia, and loss of strength. A pituitary mass was incidentally observed on magnetic resonance imaging. Histological features showed a mature teratoma formed by gut and colonic epithelium, extended lymphoid tissue with the formation of Peyer's patches, and muscular layer vestiges with a fibrous capsule. The immunohistochemical panel showed reactivity to cytokeratin (CK)7, CKAE6/AE7, carcinoembryonic antigen, octamer-binding transcription factor 4, cluster of differentiation (CD)20, CD3, vimentin, muscle actin, and pituitary tumor-transforming gene 1 in isolated cells. However, alpha-fetoprotein, beta-human chorionic gonadotropin, human placental lactogen, CK20, tumor suppressor protein 53, and Kirsten rat sarcoma were negative. This article describes the clinical and histological features of rare sellar masses as well as survival after therapy.

Contralateral Transmaxillary Approach for Resection of Chondrosarcoma of the Petrous Apex: A Case Report

BACKGROUND

Deep location and neurovascular structures make access to lesions of the petrous apex a significant challenge. A novel approach for these tumors is the contralateral transmaxillary approach.

CLINICAL PRESENTATION

A 31-year-old male was evaluated for left abducens nerve palsy. Magnetic resonance imaging (MRI) and computed tomography revealed an enhancing, lytic lesion of the petrous apex with extension to the cavernous sinus and petroclival junction. The patient underwent a combined endoscopic contralateral transmaxillary and endoscopic endonasal transclival approach for resection of the lesion. No new or worsening neurologic deficits were noted following the procedure. Pathology revealed low-grade chondrosarcoma (grade I). Postoperative MRI revealed gross total resection of the lesion. Patient underwent adjuvant radiation therapy at the discretion of radiation oncology.

CONCLUSION

The contralateral transmaxillary approach to the petrous apex allows for resection of lesions of the petrous apex with the ability to extend the dissection laterally. Excellent results achieved by institutions with advanced extended endoscopic endonasal experience can be reproduced in institutions with less experience. Further characterization of the risks and benefits of this approach is needed.

Pseudoprogression of Vestibular Schwannoma after Stereotactic Radiosurgery with Cyberknife(®): Proposal for New Response Criteria

(1) Background: Transient increase in volume of vestibular schwannomas (VS) after stereotactic radiosurgery (SRS) is common and complicates differentiation between treatment-related changes (pseudoprogression, PP) and tumor recurrence (progressive disease, PD). (2) Methods: Patients with unilateral VS (n = 63) underwent single fraction robotic-guided SRS. Volume changes were classified according to existing RANO criteria. A new response type, PP, with a >20% transient increase in volume was defined and divided into early (within the first 12 months) and late (>12 months) occurrence. (3) Results: The median age was 56 (range: 20-82) years, the median initial tumor volume was 1.5 (range: 0.1-8.6) cm³. The median radiological and clinical follow-up time was 66 (range: 24-103) months. Partial response was observed in 36% (n = 23), stable disease in 35% (n = 22) and PP in 29% (n = 18) of patients. The latter occurred early (16%, n = 10) or late (13%, n = 8). Using these criteria, no case of PD was observed. (4) Conclusion: Any volume increase after SRS for vs. assumed to be PD turned out to be early or late PP. Therefore, we propose modifying RANO criteria for SRS of VS, which may affect the management of vs. during follow-up in favor of further observation.

Rapid Automated Analysis of Skull Base Tumor Specimens Using Intraoperative Optical Imaging and Artificial Intelligence

BACKGROUND

Accurate specimen analysis of skull base tumors is essential for providing personalized surgical treatment strategies. Intraoperative specimen interpretation can be challenging because of the wide range of skull base pathologies and lack of intraoperative pathology resources.

OBJECTIVE

To develop an independent and parallel intraoperative workflow that can provide rapid and accurate skull base tumor specimen analysis using label-free optical imaging and artificial intelligence.

METHODS

We used a fiber laser-based, label-free, nonconsumptive, high-resolution microscopy method (<60 seconds per 1 × 1 mm2), called stimulated Raman histology (SRH), to image a consecutive, multicenter cohort of patients with skull base tumor. SRH images were then used to train a convolutional neural network model using 3 representation learning strategies: cross-entropy, self-supervised contrastive learning, and supervised contrastive learning. Our trained convolutional neural network models were tested on a held-out, multicenter SRH data set.

RESULTS

SRH was able to image the diagnostic features of both benign and malignant skull base tumors. Of the 3 representation learning strategies, supervised contrastive learning most effectively learned the distinctive and diagnostic SRH image features for each of the skull base tumor types. In our multicenter testing set, cross-entropy achieved an overall diagnostic accuracy of 91.5%, self-supervised contrastive learning 83.9%, and supervised contrastive learning 96.6%. Our trained model was able to segment tumor-normal margins and detect regions of microscopic tumor infiltration in meningioma SRH images.

CONCLUSION

SRH with trained artificial intelligence models can provide rapid and accurate intraoperative analysis of skull base tumor specimens to inform surgical decision-making.

Microsurgery versus stereotactic radiosurgery for small petroclival meningiomas presenting with intractable trigeminal neuropathy: A historical cohort study

BACKGROUND

Data on the outcomes of microsurgical resection (SR) and stereotactic gamma knife radiosurgery (GKRS) in patients with trigeminal neuralgia associated with small petrous apex meningiomas are scarce.

OBJECTIVE

We conducted this study to evaluate the pain relief, tumor control, and procedure costs following SR and GKRS for small petroclival meningiomas (less than 3 cm in maximal diameter) using real-world data from our center in Egypt.

MATERIAL AND METHODS

We conducted a retrospective cohort study of 47 patients with small petrous apex meningiomas presenting with intractable trigeminal nerve pain (SR: n = 22 and GKRS: n = 25). Data regarding pain relief on Barrow Neurological Institute (BNI), procedure cost, and tumor control were retrieved and analyzed using appropriate statistical tests.

RESULTS

Patients who underwent SR had lower median BNI pain intensity scores compared to those patients who underwent GKRS, and a significantly higher proportion of patients in the SR group had good BNI scores compared to those in GKRS group (P < 0.05); however, the total costs of SR were significantly less than GKRS (30,519$ vs. 92,372$, respectively).

CONCLUSION

Both SR and GKRS provide pain relief and tumor control in patients with trigeminal neuralgia associated with petrous apex meningioma. However, in the present study, SR achieved better pain control and was more affordable than GKRS.

NTCP modelling for high-grade temporal radionecrosis in a large cohort of patients receiving pencil beam scanning proton therapy for skull base and head and neck tumors

PURPOSE/OBJECTIVES

To develop a normal tissue complication probability (NTCP) model including clinical and dosimetric parameters for high-grade temporal lobe radionecroses (TRN) after pencil beam scanning (PBS) proton therapy (PT).

MATERIALS/METHODS

Data of 299 patients with skull base and Head and Neck tumors treated with PBS PT with a total dose of ≥60 Gy_RBE from 05/2004-11/2018 were included. Patients with a ≥ grade (G) 2 TRN (CTCAE v5.0 criteria) were considered as having a high-grade TRN. Nine clinical and 27 dosimetric parameters were considered for structure-wise modelling. After elimination of strongly cross-correlated variables, logistic regression models were generated using penalized LASSO regression. Bootstrapping was performed to assess parameter selection robustness. Model performance was evaluated via cross-correlation by assessing the area under the curve of receiver operating characteristic curves (AUC-ROC) and calibration with a Hosmer-Lemeshow test statistic.

RESULTS

After a median radiological follow-up of 51.5 months (range, 4-190), 27 (9%) patients developed a ≥ G2 TRN. Eleven patients had bitemporal necrosis, resulting in 38 events in 598 temporal lobes for structure-wise analysis. During Bootstrapping analysis, the highest selection frequency was found for prescription dose (PD), followed by Age, V_40Gy[%], Hypertension (HBP) and D_1cc[Gy]. During cross validation Age*PD* D_1cc[Gy]*HBP was superior in all described test statistics. Full cohort structure wise and patient wise models were built with a maximum AUC-ROC of 0.79 (structure-wise) and 0.76 (patient-wise).

CONCLUSION

While developing a logistic regression NTCP model to predict ≥ G2 TRN, the best fit was found for the model containing Age, PD, D_1cc[Gy] and HBP as risk factors. External validation will be the next step to improve generalizability and potential introduction into clinical routine.

[The DNA methylation profiling in the study and treatment of patients with meningiomas of the craniovertebral junction]

The paper presents the experience of using DNA methylation status in patients with meningiomas of the craniovertebral junction area in a neurosurgical clinic. A clinical case of combined treatment of a patient with meningioma of the craniovertebral junction and the choice of tactics based on the result of DNA methylation analysis of meningioma are described.

[Rosai-Dorfman intracranial histiocytosis: case report and literature review]

Histiocytosis is a group of idiopathic diseases accompanied by metabolic disorders and accumulation of metabolic products in histiocytes. Isolated Rosai-Dorfman histiocytosis of central nervous system is observed in less than 5% of cases. The authors report treatment and follow-up of a patient with intracranial Rosai-Dorfman disease. There were symptoms of lesion of the left cerebellopontine angle and epileptic seizures. Preoperative MRI identified two tumors (posterior cranial fossa on the left and right-sided parasagittal neoplasm). The authors carried out total resection of supratentorial tumor, after 3 weeks - subtotal resection of tumor in posterior cranial fossa. No recurrence after total resection was observed. Irradiation of infratentorial tumor with a total focal dose of 50 Gy after 6 months resulted tumor shrinkage throughout 12 months. Radiotherapy with the same dose was repeated throughout subsequent 12-month follow-up period due to progression of this focus. This treatment had a positive effect, but new skull base foci occurred. The authors emphasize the effectiveness of total resection and lower efficiency of subtotal excision combined with radiotherapy.

Intracranial chordoma: radiosurgery, hypofractionated stereotactic radiotherapy and treatment outcomes

Background

The aim of the study was to assess the results of stereotactic radiosurgery and hypofractionated stereotactic radiotherapy (SRS/SRT) for skull base chordomas.

Materials and methods

Twenty-three patients aged 12-75 were treated with SRS/SRT due to skull base chordoma. In 19 patients SRS/SRT was a part of the primary therapy, while in 4, a part of the treatment of recurrence. In 4 patients SRS/SRT was used as a boost after conventional radiotherapy and in 19 cases it was the only irradiation method applied. Patients were irradiated to total dose of 6-35 Gy and median total equivalent dose of 52 Gy.

Results

During median follow-up of 39 months, 4 patients died. One-, two- and five-year OS was 95%, 89% and 69%, respectively. In nine patients, progression of the disease was diagnosed during study period. One-, two- and five-year progression free survival (PFS) from the end of radiotherapy was 81%, 59% and 43%, respectively. Radiotherapy was well tolerated and only two patients in our group experienced moderate treatment-related toxicity.

Conclusion

SRS/SRT alone or in combination with surgery is a safe and effective method of irradiation of patients with skull base chordomas. High EQD₂ is necessary to achieve satisfactory treatment results.

A Review of Particle Therapy for Skull Base Tumors: Modern Considerations and Future Directions

Skull base tumors constitute one of the established indications for particle therapy, specifically proton therapy. However, a number of prognostic factors, practical clinical management issues, and the emerging role of carbon ion therapy remain subjects of active clinical investigation. This review summarizes these topics, assesses the present status, and reflects on future research directions focusing on the management of chordomas, one of the most aggressive skull base tumors. In addition, the role of particle therapy for benign tumors of the skull base, including pituitary adenoma and acoustic neuroma, is reviewed.

Sinonasal Renal Cell-Like Adenocarcinoma

Sinonasal renal cell-like adenocarcinoma (SNRCLA) is a newly defined, rare malignant tumor of the nasal cavity. The clinical course and response to treatment remain uncertain. The purpose of this study is to report a new case of SNRCLA and review the literature to determine clinical characteristics, treatment options, and outcomes. A 26-year-old male presented with headache, epistaxis, and nasal obstruction. Physical examination revealed a tumor involving bilateral ethmoid sinuses and MRI revealed extension through the cribriform plate. Surgical excision with endonasal and a bifrontal craniotomy was performed followed by adjuvant radiotherapy (RT). After RT, the patient had persistent disease requiring salvage surgery.

There are few previously reported cases of SNRCLA. A literature review yielded 14 previously reported cases with convincing diagnostic evidence of SNRCLA. Common presenting symptoms were epistaxis and nasal obstruction. Surgical excision was the primary treatment in fourteen cases, nine received RT, and none received chemotherapy. However, three cases had persistent or recurrent disease. Surgical excision is the mainstay of treatment for SNRCLA and adjuvant RT has been used in some patients with varying outcomes. The tumor is low grade with no reported cases of metastases or death. The best practice for treatment is yet to be determined.

Pterional Approach

The pterional approach is a workhorse in neurosurgery, to the point where perfect knowledge of its execution is essential in neurosurgical daily practice. The pterional transsylvian corridor is used to treat aneurysms involving anterior circulation, basilar apex, the proximal segment of the superior cerebellar and posterior cerebral artery, arteriovenous malformations and cavernous hemangiomas of the basal forebrain, anterior and middle skull base tumors, gliomas of the frontal, parietal, and temporal opercula, insula, mediobasal temporal region, cerebral peduncles, interpeduncular fossa, and also orbital lesions. We herein overview the core technique and variations of the pterional approach aimed at broadening surgical freedom and decreasing the risk of approach-related complications.

Chondrosarcoma of the Skull Base: A Case Study and Literature Review

Chondrosarcomas (CSs) are rare malignant tumors composed of cells derived from the transformed chondrocytes. Only 2% of the total cases of CS are found at the skull base, thus representing a 0.1-0.2% prevalence. We present the case of a patient with CS at the middle cranial fossa who was admitted for surgery to the Burdenko National Medical Research Center of Neurosurgery. In addition, we engage in a review of the literature to discuss the current approaches to the diagnostics and surgery of CS and delve deep into its embryo- and oncogenesis.

Outcomes of adolescents and young adults treated for brain and skull base tumors with pencil beam scanning proton therapy

BACKGROUND

The use of proton therapy (PT) in adolescents and young adults (AYAs) is becoming increasingly popular. This study aims to assess the outcomes and late toxicity consequences in AYAs (15-39 years) with brain/skull base tumors treated with pencil beam scanning proton therapy.

METHODS

One hundred seventy six AYAs treated curatively at the Paul Scherrer Institute (PSI) were identified. Median age was 30 years (range 15-39) and median prescribed dose was 70.0 Gy (relative biological effectiveness [RBE]) (range 50.4-76.0). The most common tumors treated were chordomas/chondrosarcomas (61.4%), followed by gliomas (15.3%), and meningiomas (14.2%).

RESULTS

After a median follow up of 66 months (range 12-236), 24 (13.6%) local only failures and one (0.6%) central nervous system (CNS) distant only failure were observed. The 6-year local control, distant progression-free survival, and overall survival were 83.2%, 97.4%, and 90.2%, respectively. The 6-year high-grade (≥grade [G] 3) PT-related late toxicity-free survival was 88.5%. Crude late toxicity rates were 26.2% G1, 37.8% G2, 12.2% G3, 0.6% G4, and 0.6% G5. The one G4 toxicity was a retinopathy and one G5 toxicity was a brainstem hemorrhage. The 6-year cumulative incidences for any late PT-related pituitary, ototoxicity, and neurotoxicity were 36.3%, 18.3%, and 25.6%; whilst high-grade (≥G3) ototoxicity and neurotoxicity were 3.4% and 2.9%, respectively. No secondary malignancies were observed. The rate of unemployment was 9.5% pre-PT, increasing to 23.8% post-PT. Sixty-two percent of survivors were working whilst 12.7% were in education post-PT.

CONCLUSIONS

PT is an effective treatment for brain/skull base tumors in the AYA population with a reasonable late toxicity profile. Despite good clinical outcomes, around one in four AYA survivors are unemployed after treatment.

Quality of Life Evaluation After Trans-Nasal Endoscopic Surgery for Skull Base Tumors

BACKGROUND

The excellent surgical results obtained with transnasal endoscopic approach to the anterior skull base (ASB) are universally recognized; less is known about the quality of life of patients after surgery.

OBJECTIVE

The aim of this study is to analyze the quality of life of patients after endoscopic transnasal surgery for the treatment of neoplasms of the ASB.

METHODS

We conducted a retrospective review of patients who underwent transnasal endoscopic surgery for treatment of ASB tumors at the Tertiary Referral Center University Hospital of Verona. All patients were asked to complete the Anterior Skull Base Questionnaire (ASBQ), the Skull Base Inventory (SBI), and the Sino-nasal Outcome Test - 22 Items (SNOT-22) after surgical treatment. The study population was divided into subgroups; a statistical analysis of the overall results and of the different questionnaire domains was performed.

RESULTS

51 patients were enrolled in this study. The average score was 3.04 for ASBQ, 4.05 for SBI and 28.88 for SNOT-22. Analysis of the overall results for the ASBQ showed a lower quality of life in patients after recurrent surgery and in female patients. The SBI showed similar results in relation to recurrent surgery and radiotherapy. Similarly, the results for SNOT-22 highlighted the negative impact of recurrent surgery and radiotherapy.

CONCLUSION

Our results confirmed that the endoscopic transnasal approach shows excellent results not only in terms of surgical outcome, but also for the possibility of ensuring a good QoL after treatment. Recurrent surgery and radiation treatments were the most important negative prognostic factors.

Mandibular metastasis as a presenting feature of a clival chordoma

Chordomas are rare tumors which arise from the embryological remnants of the notochord. These tumors can potentially arise from any region within the craniospinal axis and often clinically present as a diagnostic challenge. Chordomas are rare in patients younger than 40 years of age. The most common primary cancers that metastasize to the jaw bones are the ones originating from the breast, lung, kidney adrenal, colo-rectum, or prostate. Mandibular metastasis from a primary chordoma is an extremely rare occurrence with only five prior reports, three originating from primaries in the sacrococcygeal region, one from a lumbar spine primary and the other from a primary arising from the spheno-occipital region. A literature review did not reveal any prior reports of mandibular metastasis at presentation from a clival chordoma. We possibly report the first case of such an unusual clinical scenario in a 7-year-old male child and further discuss the evaluation and management of these rare tumors.

Submucosal Inferior Turbinectomy to Widen the Surgical Corridor for Endoscopic Endonasal Skull Base Surgery

The nasal cavity is the exclusive surgical corridor for endoscopic endonasal surgery; however, it is sometimes too narrow to allow extensive surgical maneuvering. Here we show the technique of submucosal inferior turbinectomy (SIT) to widen this surgical corridor. Its effectiveness is evaluated quantitatively by comparing pre- and intraoperative magnetic resonance images. Between March 2015 and October 2018, we performed endoscopic endonasal resection of 57 skull base tumors with 3T intraoperative magnetic resonance imaging (iMRI). Among these resections, cases with previous endonasal surgery and cases for which the iMRI did not cover the entire nasal cavity were excluded. Finally, six cases with and 19 cases without SIT were included in the subsequent retrospective analysis. We measured the dimensions of the narrowest area in inferior nasal cavity on pre- and intraoperative coronal plane gadolinium (Gd)-enhanced T1-weighted MR images using dedicated software, and compared them. The incidence rates of postoperative nasal complaints at outpatient clinics were also compared. Considerable widening of the inferior nasal cavity could be achieved with the SIT, which was statistically significant compared with those without the SIT (111.1 ± 56.5% vs. 39.4 ± 59.4%, respectively; P = 0.0093). In terms of the incidence rate of postoperative nasal complaints at 6 months, there was no statistical difference between the groups (33.3% vs. 15.8%, respectively; P = 0.35). SIT is effective for widening the surgical corridor while keeping nasal function and is especially helpful for lower clivus and laterally extended skull base lesions.

Hypofractionated Robotic Stereotactic Radiosurgery for Vagal Paragangliomas: A Novel Treatment Strategy for Cranial Nerve Preservation

OBJECTIVE

To provide the first description of hypofractionated stereotactic radiosurgery (SRS) and evaluate tumor control and safety for vagal paragangliomas (VPs), which begin at the skull base but often have significant extracranial extension.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary-referral neurotology and neurosurgery practice.

SUBJECTS AND METHODS

Five VPs in 4 patients (all male, ages 15-56 years) underwent SRS between 2010 and 2018. Outcome measures included tumor dimensions on serial imaging, cranial nerve function, and radiation side effects.

RESULTS

CyberKnife hypofractionated SRS was performed. The prescription dose was 24 or 27 Gy (maximum dose 33.4 Gy; range, 29.3-35.5 Gy) delivered in 3 equal fractions. The mean isodose line was 79% (range, 76%-82%). Four VPs were treated primarily, and 1 tumor underwent SRS to treat regrowth 2 years after microsurgical subtotal resection via the modified infratemporal fossa approach. The treatment volume ranged from 8.81 to 86.3 cm³ (mean, 35.7 cm³). All demonstrated stable size (n = 3) or regression (n = 2) at last follow-up, 63 to 85 months after SRS (mean, 76 months). One patient had stable premorbid vocal fold paralysis from a prior ipsilateral glomus jugulare tumor resection. All others demonstrated normal vagal function following SRS. Treatment-related side effects, including dysgeusia (n = 1), mucositis (n = 1), and neck soft-tissue edema (n = 2), were self-limited.

CONCLUSIONS

Hypofractionated SRS appears to be both safe and effective for treating VPs, including large-volume and predominantly extracranial tumors, while preserving vagal function. SRS should be considered as a cranial nerve preservation option, especially in settings of contralateral lower cranial nerve deficits or in those with multiple paragangliomas risking both vagal nerves.

[Treatment of petroclival meningiomas: current state of the problem]

Petroclival meningiomas (PCMs) are benign, slowly growing tumors. Surgery still remains the main treatment option for them. The desire for total resection of large extended PCMs often leads to the development or worsening of persistent neurological deficits. This paper presents a review of the world literature devoted to petroclival meningiomas. We discuss the issues of PCM classification, biology, diagnosis, and selection of the optimal algorithm for their treatment.

[Use of navigation in skull base surgery]

The review briefly presents the history of development of navigation systems in neurosurgery. The idea of the existing principles underlying the navigation systems used in neurosurgery is given. Currently, the basic principles of navigation are optical and electromagnetic. Studies are presented comparing the accuracy of various navigation systems. Optical navigation demonstrates greater accuracy compared to electromagnetic, but both methods demonstrate a submillimeter error in the experiment. The history of use of navigation in the surgery of the skull base is analyzed in detail, the most relevant areas of use of navigation within the surgery of the skull base are considered: craniofacial reconstruction, endoscopic endonasal surgery, surgery of common tumors of the skull base affecting the infratemporal, pterygopalatine fossa, temporomandibular joint. Indications for the use of navigation, limitations of the methodology are explained.

Seizure Risk following Open and Expanded Endoscopic Endonasal Approaches for Intradural Skull Base Tumors

Objectives  The incidence of seizures following a craniotomy for tumor removal varies between 15 and 20%. There has been increased use of endoscopic endonasal approaches (EEAs) for a variety of intracranial lesions due to its more direct approach to these pathologies. However, the incidence of postoperative seizures in this population is not well described. Methods  This is a single-center, retrospective review of consecutive patients undergoing EEA or open craniotomy for resection of a cranial base tumor between July 2007 and June 2014. Patients were included if they underwent an EEA for an intradural skull base lesion. Positive cases were defined by electroencephalograms and clinical findings. Patients who underwent a craniotomy to remove extra-axial skull base tumors were analyzed in the same fashion. Results  Of the 577 patients treated with an EEA for intradural tumors, 4 experienced a postoperative seizure (incidence 0.7%, 95% confidence interval [CI]: 0.002-0.02). Over the same period, 481 patients underwent a craniotomy for a skull base lesion of which 27 (5.3%, 95% CI: 0.03-0.08) experienced a seizure after surgery. The odds ratio for EEA was 0.13 (95% CI: 0.05-0.35). Both populations were different in terms of age, gender, tumor histology, and location. Conclusion  This study is the largest series looking at seizure incidence after EEA for intracranial lesions. Seizures are a rare occurrence following uncomplicated endonasal approaches. This must be tempered by selection bias, as there are inherent differences in which patients are treated with either approach that influence the likelihood of seizures.

[Stereotactic brain radiosurgery in the treatment of skull base tumors.]

Stereotactic radiosurgery has shown effectiveness in the multimodal treatment of skull base tumors, however it is suggested that in radiobiologically sensitive areas (eg. optic nerves and brainstem) the radiation dose should be reduced due to radiotoxic effects. To avoid the consequent therapeutic ineffectiveness, a recently implemented alternative is multisession radiosurgery (RCH). We retrospectively analyzed a series of patients with skull base tumors, in order to evaluate the treatment with RCH through tumor control in the post-treatment images. Age, sex, tumor histology, tumor volume, radiation protocol, pre-treatment Karnofsky performance status (KPS) previous neurosurgery and radiant treatment were also evaluated. Eighty-four patients were treated between January 2009 and January 2017. The median age was 51.5 years; females: 53.6%. There was a 92.7% non-progression after treatment, with a median follow-up time of 36 months. Treated tumors were mainly pituitary adenomas, acoustic schwannomas, and skull base meningiomas. Most of the patients received a 5-day fractionated treatment scheme, with a total dose of 25 Gy. No clinically manifest late radiotoxicity was observed. In the multivariate analysis, a high pre-treatment KPS was significantly associated with tumor non-progression. In our series, the high incidence of tumor non-progression would indicate that treatment with RCH could be a therapeutic option in some cases of skull-base tumors, mainly recurrences or tumor residuals of pituitary adenomas, neurinomas and meningiomas.

Postoperative cerebral venous sinus thrombosis in the setting of surgery adjacent to the major dural venous sinuses

OBJECTIVECerebral venous sinus thrombosis (CVST) is a known complication of surgeries near the major dural venous sinuses. While the majority of CVSTs are asymptomatic, severe sinus thromboses can have devastating consequences. The objective of this study was to prospectively evaluate the true incidence and risk factors associated with postoperative CVST and comment on management strategies.METHODSA prospective study of 74 patients who underwent a retrosigmoid, translabyrinthine, or suboccipital approach for posterior fossa tumors, or a supratentorial craniotomy for parasagittal/falcine tumors, was performed. All patients underwent pre- and postoperative imaging to evaluate sinus patency. Demographic, clinical, and operative data were collected. Statistical analysis was performed to identify incidence and risk factors.RESULTSTwenty-four (32.4%) of 74 patients had postoperative MR venograms confirming CVST, and all were asymptomatic. No risk factors, including age (p = 0.352), BMI (p = 0.454), sex (p = 0.955), surgical approach (p = 0.909), length of surgery (p = 0.785), fluid balance (p = 0.943), mannitol use (p = 0.136), tumor type (p = 0.46, p = 0.321), or extent of resection (p = 0.253), were statistically correlated with thrombosis. All patients were treated conservatively, with only 1 patient receiving intravenous fluids. There were no instances of venous infarctions, hemorrhages, or neurological deficits. The rate of CSF leakage was significantly higher in the thrombosis group than in the nonthrombosis group (p = 0.01).CONCLUSIONSThis prospective study shows that the radiographic incidence of postoperative CVST is higher than that previously reported in retrospective studies. In the absence of symptoms, these thromboses can be treated conservatively. While no risk factors were identified, there may be an association between postoperative CVST and CSF leak.

Chondrosarcoma in the Petrous Apex: Case Report and Review

Introduction  Surgical treatment of petrous apex chondrosarcoma is challenging due to the location of the tumor. Using an endoscopic technique for tumor resection is favored since it provides a minimally invasive approach. Case Presentation  A 57 years old female was admitted for acute onset of left abducens nerve palsy and occasional headache mainly on the left side of the retro-orbital area with some radiation to the left occiput. Magnetic resonance imaging (MRI) and computed tomography (CT), at the time of admission, were showed lytic lesion on the left petrous apex and left part of the clivus. Results of metastatic workup were negative. The surgical procedure considered was expanded endoscopic endonasal transclival approach to the left of the petrous apex and reconstruction with a pedicled nasoseptal flap with image guidance system. The pathology confirmed chondrosarcoma on myxoid background. The surgical procedure was uncomplicated. The abducens nerve palsy was resolved in few weeks and no new deficits occurred. Postoperative MRI showed complete resection of the tumor. Conclusion  Expanded endoscopic endonasal transclival approach to petrous apex and reconstruction appears to be safe and feasible technique, capable of achieving total removal of identified lesions near the petrous apex. Nonetheless, future studies with a greater number of patients are crucial to confirm and consolidate this initial impression.

Clinical Experience with Secondary Endoscopic Reconstruction of Clival Defects with Extracranial Pericranial Flaps

Objectives  The aim of this study is to report the clinical outcome of extracranial pericranial flaps (ePCF) used for reconstruction of clival dural defects following failure of primary repair. Design  Retrospective review of skull base database. Setting  Academic medical center. Participants  Patients undergoing reconstruction of clival defects with ePCF following endoscopic endonasal surgery (EES). Main outcome measures  Postoperative cerebrospinal fluid (CSF) leak, meningitis, and flap necrosis. Results  Seven patients (five males and two females) who underwent ePCF reconstruction for clival defects following EES were included. All patients (ages 8-64 years) had a postoperative CSF leak due to a failed primary clival reconstruction (five had one, one had two, and one had three failed CSF leak repairs prior to ePCF reconstruction). Nasoseptal and inferior turbinate (lateral nasal wall) flaps were not available for secondary reconstruction due to prior surgeries. The immediate success rate of ePCF for the reconstruction of clival defects in patients with multiple flap failures was 58%. Two patients developed CSF leaks that were successfully repaired endoscopically with the addition of free tissue grafts; one patient had partial flap necrosis that required debridement; none required an additional vascularized flap. Width of the defect, length of the defect, properties of the ePCF, and age did not demonstrate significance ( p  > 0.05) for adverse outcome. Conclusion  An ePCF is a reconstructive option for high-risk, large clival defects when other local and regional vascularized flaps are not available or fail. ePCFs can be used for reconstruction of clival defects in all populations, including pediatric patients.

The use of dehydrated amniotic membrane allograft for augmentation of dural closure in craniotomies and endoscopic endonasal transphenoidal surgeries

BACKGROUND

Primary watertight dural closure is the preferred method of postcraniotomy dural repair. However, even when ideal technique is implemented, postoperative infection, cerebrospinal fluid (CSF) leaks, pseudomeningoceles, and dural scarring are possible complications. For this reason, materials that augment the dura's ability to create a watertight seal, prevent disease transmission, and inhibit inflammatory response are sought. Dehydrated amniotic membrane (DAM) allograft appears to fulfil these requirements as it has several beneficial properties that aid wound healing, including promotion of epithelialization, scar tissue prevention, and inhibition of bacterial growth. We provide the literature's first description of the use of DAM allograft to supplement dural closures for craniotomies and transsphenoidal surgeries.

METHODS

We conducted a pilot study, retrospectively reviewing our institution's database of craniotomies and transsphenoidal surgeries that utilized DAM to augment dural closure.

RESULTS

One hundred fifty-five cases, including 102 new craniotomies for supratentorial lesions, one re-do craniotomy for supratentorial recurrent glioma, 18 craniotomies for infratentorial lesions, 1 craniotomy for anterior skull base schwannoma, 32 transphenoidal surgeries, and 1 combined craniotomy and transnasal endoscopic surgery, used DAM allograft to augment dural closure. Only one complication occurred (0.6% complication rate), which was a superficial wound infection requiring washout without craniectomy. No CSF leaks occurred.

CONCLUSIONS

This pilot study demonstrates that dehydrated amniotic membrane allograft can be safely utilized as an adjunct during dural closures for craniotomies and transsphenoidal surgeries.

[Neurological semiotics of benign craniofacial tumors]

AIM

To identify the most frequently occurring symptoms resulting from the affection of internal and external skull base in patients with benign tumors of the anterior and middle cranial base.

MATERIAL AND METHODS

The authors analyzed a complex of history, clinical, and instrumental data as well as results of combined treatment of 642 patients with benign tumors of the anterior and middle cranial base operated Medical Research between 2007 and 2011.

RESULTS

Neurological signs and symptoms in patients with benign tumors of the anterior cranial base, parasellar region, and middle cranial fossa were studied. In the majority of cases, the tumor extended extracranially. The most common groups of symptoms were identified and described, the most important groups are presented in the diagrams. The proposed scheme is applicable also for malignant tumors or other mass lesions of the same localization.

CONCLUSION

Effective treatment and selection of the best management of a patient depends on modern medical approaches and techniques including neuroimaging. Careful assessment of symptoms is crucial in detection of tumors in the early stage. Dynamic monitoring of the patient using the proposed scheme will contribute to early detection of tumor recurrence or progression.

[Facial nerve injury in neurosurgery: a rehabilitation potential of botulinum therapy]

Surgical treatment of posterior cranial fossa and cerebellopontine angle tumors is associated with a risk of facial nerve dysfunction. The causes for facial muscle paresis include nerve compression by the tumor, destruction of the nerve structure by the tumor growing from nerve fibers, nerve injury during surgical removal of the tumor, etc. The first 3 months after facial nerve injury are a potential therapeutic window for the use of botulinum toxin type A (BTA). During this period, the drug is introduced both in the healthy side to improve the facial symmetry at rest and during mimetic movements and in the affected side to induce drug-induced ptosis. Post-paralytic syndrome develops 4-6 months after facial nerve injury. At this stage, administration of BTA is also an effective procedure; in this case, drug injections are performed on the affected side at small doses and symmetrically on the healthy side at doses doubling those for the affected side. BTA injections are mandatory in complex treatment of facial muscle paralysis.

18FDG PET/CT in Routine Surveillance of Asymptomatic Patients following Treatment of Sinonasal Neoplasms

Objective Sinonasal neoplasms have a high rate of recurrence following treatment, and current guidelines support the use of a variety of surveillance techniques. Recent work demonstrates that performance parameters of surveillance modalities may differ with sinonasal tumors in particular when compared with head and neck tumors overall. This study aims to characterize the value of ¹⁸fluorodeoxyglucose (¹⁸FDG) positron emission tomography/computed tomography (PET/CT) as a screening tool in asymptomatic patients. Study Design Retrospective cohort study. Setting Hospital of the University of Pennsylvania and Pennsylvania hospital. Methods Records of asymptomatic patients without suspicious endoscopy or suspicious imaging other than PET during the first 3 years following definitive treatment for sinonasal malignancy were screened and analyzed for inclusion in the cohort. Disease recurrence was determined by biopsy following suspicious PET evaluation. Results PET/CT scans (n = 111) were performed for 45 disease-free asymptomatic patients with no evidence of disease on endoscopy, and 6.3% were suspicious and prompted biopsy during this period, revealing 3 cases of disease recurrence. Overall specificity for PET/CT alone was 96.3% (95% CI, 90.7%-99.0%), with a negative predictive value of 99% (95% CI, 94.8%-100%). All recurrences were detected between 7 and 12 months, and all patients with true recurrence diagnosed by PET/CT had extrasinonasal involvement of tumor at the time of surgery. Conclusion We examined performance parameters of ¹⁸FDG PET/CT in asymptomatic patients with no evidence of disease on endoscopy during the posttreatment period for sinonasal malignancy. The ability of PET/CT to detect recurrences that may be missed by structural imaging or endoscopy makes it a valuable tool for clinicians.

Periodic olfactory assessment in patients undergoing skull base surgery with preservation of the olfactory strip

OBJECTIVES/HYPOTHESIS

Others have reported olfactory disturbances following endoscopic approaches to the skull base. However, there is a lack of consensus on the extent and duration of dysfunction. This study aimed to compare our results with previously published work and to validate the olfactory strip-sparing approach.

STUDY DESIGN

Prospective study to assess olfaction in 50 patients scheduled to undergo resection of skull base tumors via extended endoscopic approaches.

METHODS

Patients were divided into two groups. Group I had a nasoseptal flap (NSF), and group II included patients in whom rescue flaps were performed bilaterally. Olfactory outcomes were assessed using repeated University of Pennsylvania Smell Identification Test at baseline, 6 weeks, 3 months, and 6 months following surgery.

RESULTS

Ultimately, 42 patients (seven group I and 35 group II) were available for assessment. Scores for group I were lower than at baseline at 6 weeks postoperatively (30.71 ± 5.5 vs. 24.5 ± 5.4; P = .05). However, by the third postoperative month the scores had improved to a level that was not significantly different from baseline (29.0 ± 3.7; P = .5). At 6 months, the score was 30.0 ± 3.9. Patients in group II showed no difference between their baseline and 6-week scores (31.5 ± 5.3 vs. 29.7 ± 5.9; P = .16). Six months postoperatively, the score was significantly higher (33.78 ± 3.6; P = .04).

CONCLUSIONS

Expanded endoscopic approaches to skull base tumors involving reconstruction with an NSF are associated with a short-term negative impact on olfaction. Olfaction does not seem to be affected by the surgical resection of pituitary adenomas associated with rescue flaps. Identification of the olfactory epithelium and meticulous harvesting of the NSF are critical to preserve olfaction.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:1970-1975, 2017.

Dosimetric Analysis of Neural and Vascular Structures in Skull Base Tumors Treated with Stereotactic Radiosurgery

Objective To examine the relationship between the prescribed target dose and the dose to healthy neurovascular structures in patients with vestibular schwannomas treated with stereotactic radiosurgery (SRS). Study Design Case series with chart review. Setting SRS center from 2011 to 2013. Subjects Twenty patients with vestibular schwannomas treated at the center from 2011 to 2013. Methods Twenty patients with vestibular schwannomas were included. The average radiation dose delivered to healthy neurovascular structures (eg, carotid artery, basilar artery, facial nerve, trigeminal nerve, and cochlea) was analyzed. Results Twenty patients with vestibular schwannomas who were treated with fused computed tomography/magnetic resonance imaging-guided SRS were included in the study. The prescribed dose ranged from 10.58 to 17.40 Gy over 1 to 3 hypofractions to cover 95% of the target tumor volume. The mean dose to the carotid artery was 5.66 Gy (95% confidence interval [CI], 4.53-6.80 Gy), anterior inferior cerebellar artery was 8.70 Gy (95% CI, 4.54-12.86 Gy), intratemporal facial nerve was 3.76 Gy (95% CI, 3.04-4.08 Gy), trigeminal nerve was 5.21 Gy (95% CI, 3.31-7.11 Gy), and the cochlea was 8.70 Gy (95% CI, 7.81-9.59 Gy). Conclusions SRS for certain vestibular schwannomas can expose the anterior inferior cerebellar artery (AICA) and carotid artery to radiation doses that can potentially initiate atherosclerotic processes. The higher doses to the AICA and carotid artery correlated with increasing tumor volume. The dose delivered to other structures such as the cochlea and intratemporal facial nerve appears to be lower and much less likely to cause immediate complications when shielded.

Comparison of probabilistic and deterministic fiber tracking of cranial nerves

OBJECTIVE The depiction of cranial nerves (CNs) using diffusion tensor imaging (DTI) is of great interest in skull base tumor surgery and DTI used with deterministic tracking methods has been reported previously. However, there are still no good methods usable for the elimination of noise from the resulting depictions. The authors have hypothesized that probabilistic tracking could lead to more accurate results, because it more efficiently extracts information from the underlying data. Moreover, the authors have adapted a previously described technique for noise elimination using gradual threshold increases to probabilistic tracking. To evaluate the utility of this new approach, a comparison is provided with this work between the gradual threshold increase method in probabilistic and deterministic tracking of CNs. METHODS Both tracking methods were used to depict CNs II, III, V, and the VII+VIII bundle. Depiction of 240 CNs was attempted with each of the above methods in 30 healthy subjects, which were obtained from 2 public databases: the Kirby repository (KR) and Human Connectome Project (HCP). Elimination of erroneous fibers was attempted by gradually increasing the respective thresholds (fractional anisotropy [FA] and probabilistic index of connectivity [PICo]). The results were compared with predefined ground truth images based on corresponding anatomical scans. Two label overlap measures (false-positive error and Dice similarity coefficient) were used to evaluate the success of both methods in depicting the CN. Moreover, the differences between these parameters obtained from the KR and HCP (with higher angular resolution) databases were evaluated. Additionally, visualization of 10 CNs in 5 clinical cases was attempted with both methods and evaluated by comparing the depictions with intraoperative findings. RESULTS Maximum Dice similarity coefficients were significantly higher with probabilistic tracking (p < 0.001; Wilcoxon signed-rank test). The false-positive error of the last obtained depiction was also significantly lower in probabilistic than in deterministic tracking (p < 0.001). The HCP data yielded significantly better results in terms of the Dice coefficient in probabilistic tracking (p < 0.001, Mann-Whitney U-test) and in deterministic tracking (p = 0.02). The false-positive errors were smaller in HCP data in deterministic tracking (p < 0.001) and showed a strong trend toward significance in probabilistic tracking (p = 0.06). In the clinical cases, the probabilistic method visualized 7 of 10 attempted CNs accurately, compared with 3 correct depictions with deterministic tracking. CONCLUSIONS High angular resolution DTI scans are preferable for the DTI-based depiction of the cranial nerves. Probabilistic tracking with a gradual PICo threshold increase is more effective for this task than the previously described deterministic tracking with a gradual FA threshold increase and might represent a method that is useful for depicting cranial nerves with DTI since it eliminates the erroneous fibers without manual intervention.

[Neurosurgery in a patient on dual antiplatelet therapy. Case report and the review of the literature]

INTRODUCTION

A neurosurgical intervention in a patient on dual antiplatelet therapy is a serious challenge for both the neurosurgeon and anesthesiologist..

MATERIAL AND METHODS

The article describes a clinical case of a successful urgent neurosurgical intervention (ventriculoperitoneostomy for obstructive hydrocephalus caused by a large meningioma of the posterior surface of the petrous pyramid) in a patient on dual antiplatelet therapy (DAT) due to a recently placed coronary stent..

CONCLUSION

Given a high risk of coronary stent thrombosis, the surgery was performed in the presence of ongoing DAT. There were no intracranial hemorrhagic complications, but subcutaneous hemorrhagic complications developed. The article discusses the features of managing similar patients whose number is growing.

Imaging of skull base lesions

Skull base imaging requires a thorough knowledge of the complex anatomy of this region, including the numerous fissures and foramina and the major neurovascular structures that traverse them. Computed tomography (CT) and magnetic resonance imaging (MRI) play complementary roles in imaging of the skull base. MR is the preferred modality for evaluation of the soft tissues, the cranial nerves, and the medullary spaces of bone, while CT is preferred for demonstrating thin cortical bone structure. The anatomic location and origin of a lesion as well as the specific CT and MR findings can often narrow the differential diagnosis to a short list of possibilities. However, the primary role of the imaging specialist in evaluating the skull base is usually to define the extent of the lesion and determine its relationship to vital neurovascular structures. Technologic advances in imaging and radiation therapy, as well as surgical technique, have allowed for more aggressive approaches and improved outcomes, further emphasizing the importance of precise preoperative mapping of skull base lesions via imaging. Tumors arising from and affecting the cranial nerves at the skull base are considered here.

Bilateral dissecting aneurysms of the internal carotid arteries misdiagnosed as skull base tumors: A case report

A 45-year-old female presented with a five-year history of intermittent headaches and a two-month history of left hypoglossal nerve palsy. Computed tomography and magnetic resonance imaging of the head revealed space-occupying lesions in the base of the skull with accompanying bone erosion, which were suggestive of skull base chordomas. However, an endoscopic endonasal transsphenoidal biopsy was also performed and pathological analysis of the lesion suggested a thrombosis. Cranial magnetic resonance angiography revealed old dissecting aneurysms of the bilateral internal carotid arteries (ICAs), which led to a definitive diagnosis. The patient was successfully treated with anticoagulants and antiplatelet agents. The present case study suggests that, for patients with space-occupying lesions of the skull base and symptoms of cranial nerve palsy, the possibility of an ICA dissection should be prioritized during the differential diagnosis.

Utility of dynamic computed tomography angiography in the preoperative evaluation of skull base tumors

OBJECT

The anatomical complexity of skull base tumors mandates detailed preoperative planning for safe resection. In particular, the location of critical vascular and bony structures can influence the surgical approach. Traditional methods, such as MRI, MR angiography and/or venography (MRA/MRV), CT angiography and/or venography (CTA/CTV), and digital subtraction angiography, each have their limitations. One alternative that combines the benefits of both detailed anatomy compatible with intraoperative image guidance and visualization of the vascular flow is the 320-detector row dynamic volume CTA/CTV. The authors investigated this technique's impact on the surgical approach used in a series of complex intracranial tumors.

METHODS

All patients with complex intracranial tumors who had undergone preoperative dynamic CTA/CTV as well as MRI in the period from July 2010 to June 2012 were retrospectively reviewed. Those in whom only routine CTA/CTV sequences had been obtained were excluded. Clinical records, including imaging studies, operative reports, and hospital course, were reviewed. Ease in detecting specific major arterial and venous tributaries using dynamic CTA/CTV was graded for each case. Furthermore, 2 skull base neurosurgeons projected a desired surgical approach for each tumor based on MRI studies, independent of the CTA/CTV sequences. The projected approach was then compared with the ultimately chosen surgical approach to determine whether preoperative awareness of vasculature patterns altered the actual operative approach.

RESULTS

Sixty-four patients were eligible for analysis. Dynamic CTA/CTV successfully demonstrated circle of Willis arteries, major draining sinuses, and deep internal venous drainage in all cases examined. The superior petrosal sinus, vein of Labbé, tentorial veins, and middle fossa veins were also identified in a majority of cases, which played an important role in preoperative planning. Visualization of critical vascular-especially venous-anatomy influenced the surgical approach in 39% (25 of 64) of the cases.

CONCLUSIONS

Dynamic CTA/CTV has been applied to few neurosurgical disease pathologies to date. This noninvasive technology offers insight into vascular flow patterns as well as 3D anatomical relationships and provides thin-cut sequences for intraoperative navigation. The authors propose dynamic CTA as an addition to the preoperative planning for complex skull base tumors.

Giant prolactinoma presenting as a skull base tumor with erosion of the cervical vertebrae: pronounced responsiveness to dopamine agonist treatment

Giant prolactinomas are rare and usually associated with symptoms attributable to hypopituitarism and compression of juxtasellar structures such as the cranial nerves of the cavernous sinus and the optic chiasm. Occasionally, they masquerade as skull base tumors with atypical symptoms. We describe a patient who presented with a low-energy trauma in the neck region that led to the initial diagnosis of a large skull base tumor eroding the cervical vertebrae. After stabilizing surgery, the patient responded to dopamine agonist therapy with normalization of serum prolactin levels and pronounced reduction in tumor volume.

Work productivity and neuropsychological function in persons with skull base tumors

BACKGROUND

Skull base tumors comprise many common benign brain tumors. Treatment has advanced, allowing many survivors to return to work. However, literature is limited about the neuropsychological status of these patients prior to treatment. Literature pertaining to the relationship between neuropsychological functioning and occupational ability prior to surgical intervention is even more limited. The purpose of this analysis was to evaluate the impact of neuropsychological function on work productivity in persons with skull base tumors prior to resection.

METHODS

Neuropsychological function and work productivity were assessed in adults newly diagnosed with skull base tumors (n = 45) prior to surgical intervention. Univariate analyses identified potential predictors of work limitations; variables with P < .10 were analyzed using multivariate regression analyses controlled for age, sex, tumor type, and education.

RESULTS

Poorer mental attention and flexibility (MF) and higher depressive symptoms (DS) were significantly associated with poor time management at work (MF: β = -0.59, P = .01; DS: β = 3.42, P < .01; R² = 0.54). Difficulty meeting physical work demands was significantly associated with poorer visuospatial ability (VA) and higher depressive symptoms (VA: β = -3.30, P = .05; DS: β = 2.29, P < .01; R² = 0.29). Lower learning and memory scores (LM) and higher depressive symptoms were significantly associated with difficulty meeting mental-interpersonal work demands (LM: β = -3.39, P = .04; DS: β = 3.25, P < .01; R² = 0.47) and overall health-related loss of work productivity (LM: β = -0.72, P = .05; DS: β = 0.659, P < .001; R² = 0.43).

CONCLUSION

Domains of neuropsychological function that predicted work productivity were identified. Future research should examine neuropsychological function, depressive symptoms, and work productivity across the care trajectory from diagnosis through long-term survivorship.

Impact of Chemoradiotherapy on CSF Leak Repair after Skull Base Surgery

Background Transnasal endoscopic resection (TER) has become the treatment of choice for many skull base tumors. A major limitation of TER is the management of large dural defects and the need for repair of cerebrospinal fluid (CSF) leaks, particularly among patients who are treated with chemotherapy (CTX) or radiotherapy (RT). The objective of this study is to determine the impact of CTX and RT on the success of CSF leak repair after TER. Methods We performed a retrospective chart review of a single-institution experience of TER from 1992 to 2011. Results We identified 28 patients who had endoscopic CSF leak repair after resection of malignant skull base tumors. Preoperative RT was utilized in 18 patients, and 9 had undergone CTX. All patients required CSF leak repair with rotational flaps after cribriform and/or dural resection. CSF leak repair failed in three patients (11%). A history of RT or CTX was not associated with failed CSF leak repair. Conclusion Adjuvant or neoadjuvant CTX or RT is not associated with failed CSF leak repair. Successful CSF leak repair can be performed in patients with malignant skull base tumors with an acceptable risk profile.

Management of hypoglossal schwannomas: single institutional experience of 14 cases

Background Hypoglossal schwannomas are rare intracranial neoplasms. Microsurgical resection with the goal of cure is the aim of management but is associated with a high rate of postoperative morbidity. Objective The objective of the study was to outline the clinical presentation, radiologic characteristics, surgical techniques, postoperative morbidity, and long-term follow-up results for hypoglossal schwannomas. Methods Patients treated for hypoglossal schwannoma at the Department of Neurosurgery of a tertiary-level referral institution from January 2001 until December 2010 were analyzed retrospectively using hospital records. Results There were 14 patients who were treated in the study period. Tongue atrophy and swallowing difficulties were the most common presenting symptoms. Surgery done in 12 patients using a variety of approaches (retromastoid retrosigmoid suboccipital in 9, midline suboccipital in 2, and far lateral in 1). Five patients having small residual tumors received gamma knife (GK) subsequently. two patients received primary GK stereotactic radiosurgery. Three patients had permanent morbidity in the form of cranial nerve paresis. Immediate postoperative complications like cerebrospinal fluid leak and pneumonia were present in three patients. Conclusion Complete microsurgical resection is often associated with a high rate of morbidity. Subtotal and near-total resection followed by stereotactic radiosurgery or observation now offers an alternative approach.

Hepatoid adenocarcinoma of the anterior skull base: a case report

We report the first case of hepatoid adenocarcinoma of the skull base, as well as the first reported case in the head and neck region. Hepatoid adenocarcinoma is a rare, aggressive, extrahepatic malignancy with a distinct morphological similarity to hepatocellular carcinoma, in the absence of primary hepatic disease. A 45-year-old man presented with sinus headaches and retro-orbital pain and was found to have a nasopharyngeal mass on endoscopy and a large, destructive sinonasal mass extending intracranially on imaging. Histo- and cytopathological features were similar to hepatocellular carcinoma, and the cells were immunoreactive for α-fetoprotein, epithelial membrane antigen, periodic acid-Schiff, cytokeratin (CK)8/18, CK19, and S100.

Lateral Transmandibular Approach to the Skull Base in Children: Three Case Reports

The choice of surgical approach to tumors of the cranial base in children is determined by strict criteria. The criteria include optimal visibility for the surgeon, minimal possible impairment of facial skull growth, and the preservation of motor and sensory nerve integrity. From 1993 to 1996, three children (6 years old, 22 months old, 6 months old, respectively) underwent surgery to resect cranial base tumors through a modified lateral transmandibular approach. In all three patients a preauricular incision with temporal and submandibular extensions was performed. After the mandible was prepared, an osteotomy was conducted cranially to the mandibular foramen. When the capitulum was temporarily disarticulated, wide access to the cranial base was provided and the tumors were resected. Two of these children were available for follow-up, and we continue to observe their development. Given the severity of their conditions, treatment yielded good results. Growth impairment of the mandible was corrected by the distraction osteogenesis technique.