Microsurgical resection of a large petroclival meningioma through an extended retrosigmoid approach: how I do it

BACKGROUND

Petroclival meningiomas are challenging tumors. Several skull base approaches have been proposed in the last decades, with variable rates of postoperative morbidity and extent of resection.

METHODS

We herein reported the step-by-step microsurgical resection of a large petroclival meningioma through an extended retrosigmoid approach. Detailed surgical technique has been accompanied by a 2D operative video.

CONCLUSION

The extended retrosigmoid approach allowed for a safe gross total resection of the tumor, as confirmed by the postoperative MRI. The patient did not experience any new postoperative deficit, despite a transient diplopia, and was discharged on postoperative day 7.

Phantom study of a fully automatic radioactive seed placement robot for the treatment of skull base tumours

BACKGROUND

Interstitial brachytherapy is a form of intensive local irradiation that facilitates the effective protection of surrounding structures and the preservation of organ functions, resulting in a favourable therapeutic response. As surgical robots can perform needle placement with a high level of accuracy, our team developed a fully automatic radioactive seed placement robot, and this study aimed to evaluate the accuracy and feasibility of fully automatic radioactive seed placement for the treatment of tumours in the skull base.

METHODS

A fully automatic radioactive seed placement robot was established, and 4 phantoms of skull base tumours were built for experimental validation. All the phantoms were subjected to computed tomography (CT) scans. Then, the CT data were imported into the Remebot software to design the preoperative seed placement plan. After the phantoms were fixed in place, navigation registration of the Remebot was carried out, and the automatic seed placement device was controlled to complete the needle insertion and particle placement operations. After all of the seeds were implanted in the 4 phantoms, postoperative image scanning was performed, and the results were verified via image fusion.

RESULTS

A total of 120 seeds were implanted in 4 phantoms. The average error of seed placement was (2.51 ± 1.44) mm.

CONCLUSION

This study presents an innovative, fully automated radioactive particle implantation system utilizing the Remebot device, which can successfully complete automated localization, needle insertion, and radioactive particle implantation procedures for skull base tumours. The phantom experiments showed the robotic system to be reliable, stable, efficient and safe. However, further research on the needle-soft tissue interaction and deformation mechanism of needle puncture is still needed.

Endoscopic endonasal approach for olfactory groove meningioma resection: Strategies and outcomes in a retrospective case series

OBJECTIVE

Though the endoscopic endonasal approach (EEA) is a widely accepted treatment for skull base tumors, the specific use of EEA for olfactory groove meningiomas (OGMs) is debated, with variable outcomes reported in the literature. We review the surgical results of OGM resections for one surgeon including the operative approach, surgical nuances, and outcomes, with a focus on factors relating to patient selection which favor EEA over transcranial approaches.

METHODS

We retrospectively reviewed thirteen cases of endoscopic endonasal resection of olfactory groove meningiomas. Patient characteristics, clinical characteristics, surgical outcomes, and complications were analyzed. Extent of resection was determined based on volumetric analysis of pre- and postoperative MRI.

RESULTS

Anatomic characteristics that render a tumor difficult to access fully are lateral extension beyond the mid-orbit and anterior extension to the falx. Simpson Grade I resection was achieved in 11/13 (84.6 %) cases. Mean pre-operative tumor volume was 8.99 cm3 (range 2.19-16.79 cm3), and 92 % of tumors were WHO grade I. We demonstrate 2 cases of smell preservation, possible with small unilateral tumors and tumors that are confined to either the anterior or posterior portion of the cribriform plate. The post-operative CSF leak rate was 7.7 %, without prophylactic lumbar CSF drainage. The mortality rate was 7.7 % (n = 1) after infectious complications following CSF leak.

CONCLUSIONS

Endoscopic endonasal resection of olfactory groove meningiomas is an effective and safe operative method with outcomes and complication rates comparable to transcranial approaches. Key considerations include careful patient selection and familiarity with technical nuances of endoscopic endonasal approach for this specific tumor type.

Prospective Analysis of Radiation-Induced Contrast Enhancement and Health-Related Quality of Life After Proton Therapy for Central Nervous System and Skull Base Tumors

PURPOSE

Intracerebral radiation-induced contrast enhancement (RICE) can occur after photon as well as proton beam therapy (PBT). This study evaluated the incidence, characteristics, and risk factors of RICE after PBT delivered to, or in direct proximity to, the brain and its effect on health-related quality of life (HRQoL).

METHODS AND MATERIALS

Four hundred twenty-one patients treated with pencil beam scanning PBT between 2017 and 2021 were included. Follow-up included clinical evaluation and contrast-enhanced magnetic resonance imaging at 3, 6, and 12 months after treatment completion and annually thereafter. RICE was graded according to Common Terminology Criteria for Adverse Events version 4, and HRQoL parameters were assessed via European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ)-C30 questionnaires.

RESULTS

The median follow-up was 24 months (range, 6-54), and median dose to 1% relative volume of noninvolved central nervous system (D1%CNS) was 54.3 Gy relative biologic effectiveness (RBE; range, 30-76 Gy RBE). The cumulative RICE incidence was 15% (n = 63), of which 10.5% (n = 44) were grade 1, 3.1% (n = 13) were grade 2, and 1.4% (n = 6) were grade 3. No grade 4 or 5 events were observed. Twenty-six of 63 RICE (41.3%) had resolved at the latest follow-up. The median onset after PBT and duration of RICE in patients in whom the lesions resolved were 11.8 and 9.0 months, respectively. On multivariable analysis, D1%CNS > 57.6 Gy RBE, previous in-field radiation, and diabetes mellitus were identified as significant risk factors for RICE development. Previous radiation was the only factor influencing the risk of symptomatic RICE. After PBT, general HRQoL parameters were not compromised. In a matched cohort analysis of 54/50 patients with and without RICE, no differences in global health score or functional and symptom scales were seen.

CONCLUSIONS

The overall incidence of clinically relevant RICE after PBT is very low and has no significant negative effect on long-term patient QoL.

The trans-sylvian trans-petrosal "half & half" approach-a how I do it

BACKGROUND

Petroclival meningiomas are one of the most challenging tumors to be operated in the realm of neurosurgery. Many approaches have been developed over the years.

METHOD

The authors describe the Half & Half (H&H) approach whose main indication is petroclival meningiomas with suprasellar extension. The part of the tumor located above CN III and in the retrochiasmatic space is addressed through a trans-sylvian, while the petroclival portion is through an extradural anterior petrosectomy approach. The wide surgical corridor given by this approach allows extensive tumor resection while avoiding the risk associated with the manipulation of intracavernous neurovascular structures.

CONCLUSION

The H&H approach is an effective strategy to maximize the safe resection of petroclival meningiomas.

[Preoperative Simulation of Endoscopic Endonasal Approach for Craniopharyngiomas or Tuberculum Sellae Meningiomas]

Preoperative simulation for endoscopic endonasal approach(EEA)using computed tomography and magnetic resonance imaging evaluates tumor extension and the relationship between adjacent structure(the pituitary stalk, major vessels, and cranial nerves); therefore, preoperative planning of nasal procedure, skull base bony removal, and cranial base reconstruction are possible. Additionally, three-dimensional(3D)fusion image aids surgeons to visualize intraoperative 3D findings. These preoperative simulations are critical to avoid complications and predict pitfalls perioperatively. However, tumor consistency or adhesion with adjacent structure cannot be predicted but is judged perioperatively, which affects the extent of tumor resection. This manuscript describes important points of preoperative simulation for EEA, especially the transplanum-transtuberculum approach for craniopharyngiomas or tuberculum sellae meningiomas, showing some examples in patients.

Analysis of visual impairment score in a series of 48 tuberculum sellae meningiomas operated on via the endoscopic endonasal approach

OBJECTIVE

Tuberculum sellae meningioma (TSM) represents a complex skull base tumor. The primary goals of surgical treatment are represented by maximal safe resection and visual recovery; therefore, appropriate patient selection is critical to optimize results. In the last 2 decades, the endoscopic endonasal approach (EEA) has appeared as a successful and viable strategy for the management of these tumors. The authors identified preoperative factors associated with extent of resection and visual outcome after EEA for TSM.

METHODS

In this retrospective cohort study, the authors analyzed patients who underwent extended endoscopic endonasal surgery for TSM between January 2005 and April 2022 at the Division of Neurosurgery, Università degli Studi di Napoli Federico II, Naples, Italy. Tumor size, vessel encasement, and optic canal involvement were classified according to University of California, San Francisco, score. Visual acuity and visual fields were analyzed according to the visual impairment score (VIS), defined as a four-level classification: grade 1 (VIS 0-25), grade 2 (VIS 26-50), grade 3 (VIS 51-75), and grade 4 (VIS 76-100). Ophthalmological functions were tested preoperatively and during the early postoperative period (within 6 months after surgery) and late postoperative period.

RESULTS

A total of 48 patients were enrolled. Forty-one (85.4%) patients experienced blurred vision or visual field defect as a presenting sign. Gross-total resection was achieved in 40 (83.3%), near-total resection in 2 (4.2%), and subtotal resection in 6 (12.5%). Visual defect improved in 82.9% (34/41) of cases, 12.2% (5/41) had no significant changes, and 2.4% (1/41) had worsened visual defect. The mean change in VIS was 42% (95% CI 58.77-31.23). Visual outcome was poorer when preoperative VIS (VIS-pre) was greater than 25 (p = 0.02). Six postoperative CSF leaks occurred (12.5%), and 1 patient (2.1%) required revision surgery.

CONCLUSIONS

The EEA is a safe and effective approach for TSM removal, with the advantage of preserving optic apparatus vascularization, and can promote gross-total resection and visual improvement. The authors have defined four categories based on VIS that relate to postoperative outcome: the lower the VIS-pre, the higher the rate of postoperative VIS improvement. This finding may be useful for predicting a patient's visual outcome at the preoperative stage.

Effect of Optic Canal Opening on Postoperative Visual Acuity in Patients with Tuberculum Sellae Meningiomas

BACKGROUND

 Tuberculum sellae meningiomas (TSMs) account for 5 to 10% of all intracranial meningiomas. They typically invade the optic canal and displace the optic nerve upward and laterally. The transcranial approach has been the standard surgical approach, while the transsphenoidal approach has been proposed for its minimally invasive nature; however, some reservations concerning this approach remain.

METHODS

 From January 2000 to December 2018, a total of 97 patients who were diagnosed with TSM with invasion of the optic canal were enrolled and underwent microsurgery for tumor removal with optic canal opening. A retrospective analysis was performed on the effect of optic canal opening on postoperative visual acuity improvement. The median follow-up was 17.4 months (range: 3-86 months).

RESULTS

 Among the 97 patients with TSM involving the optic canal, optic canal invasion was seen on preoperative imaging in 73 patients and during intraoperative exploration in all patients. In total, 87/97 patients (89.7%) underwent optic canal opening to remove tumors involving the optic canal, and the rate of total macroscopic resection of tumors invading the optic canal was 100%. Among the 10 patients who did not undergo optic canal opening, the rate of total resection of tumors involving the optic canal was 80% (8/10, p < 0.001). There were no deaths or serious complications. The postoperative visual acuity improvement rate was 64.4%, 23.7% maintained the preoperative level, and the visual acuity deteriorated 11.9%.

CONCLUSION

 Intraoperative optic canal opening is the key to total resection of TSMs involving the optic canal and improving postoperative visual acuity.

[Endoscopic transnasal resection of clival meningiomas]

BACKGROUND

Surgical treatment of ventral and ventrolateral meningiomas of posterior cranial fossa is difficult in modern neurosurgery. This is due to peculiarities of approach to these areas and concentration of critical structures (cranial nerves and great vessels). Currently, endoscopic transnasal approach to these meningiomas allows partial, and in some cases, total resection. However, this technique is not widespread.

OBJECTIVE

To analyze the world literature data on postoperative outcomes in patients with clival and petroclival meningiomas after endoscopic transnasal resection.

MATERIAL AND METHODS

We analyzed 22 articles representing treatment of 61 patients with clival and petroclival meningiomas.

RESULTS

Total or near-total resection was achieved in 22.9% of cases, subtotal resection - 40.9%, partial resection - 26.2% (data were not provided in other cases). Even partial and subtotal resection leads to significant regression of symptoms.

CONCLUSION

Endoscopic transnasal surgery is a full-fledged alternative to transcranial approaches in surgical treatment of clival meningiomas. It is also an additional option for patients with petroclival meningiomas after ineffective transcranial approaches. Transnasal tumor shrinkage and devascularization lead to brainstem decompression, regression of hydrocephalus and baseline clinical symptoms.

Endonasal, supraorbital, and transorbital approaches: minimal access endoscope-assisted surgical approaches for meningiomas in the anterior and middle cranial fossae

OBJECTIVE

Minimally invasive endoscope-assisted approaches to the anterior skull base offer an alternative to traditional open craniotomies. Given the restrictive operative corridor, appropriate case selection is critical for success. In this paper, the authors present the results of three different minimal access approaches to meningiomas of the anterior and middle fossae and examine the differences in the target areas considered appropriate for each approach, as well as the outcomes, to determine whether the surgical goals were achieved.

METHODS

A consecutive series of the endoscopic endonasal approach (EEA), supraorbital approach (SOA), or transorbital approach (TOA) for newly diagnosed meningiomas of the anterior and middle fossa skull base between 2007 and 2022 were examined. Probabilistic heat maps were created to display the distribution of tumor volumes for each approach. Gross-total resection (GTR), extent of resection, visual and olfactory outcomes, and postoperative complications were assessed.

RESULTS

Of 525 patients who had meningioma resection, 88 (16.7%) were included in this study. EEA was performed for planum sphenoidale and tuberculum sellae meningiomas (n = 44), SOA for olfactory groove and anterior clinoid meningiomas (n = 36), and TOA for spheno-orbital and middle fossa meningiomas (n = 8). The largest tumors were treated using SOA (mean volume 28 ± 29 cm3), followed by TOA (mean volume 10 ± 10 cm3) and EEA (mean volume 9 ± 8 cm3) (p = 0.024). Most cases (91%) were WHO grade I. GTR was achieved in 84% of patients (n = 74), which was similar to the rates for EEA (84%) and SOA (92%), but lower than that for TOA (50%) (p = 0.002), the latter attributable to spheno-orbital (GTR: 33%) not middle fossa (GTR: 100%) tumors. There were 7 (8%) CSF leaks: 5 (11%) from EEA, 1 (3%) from SOA, and 1 (13%) from TOA (p = 0.326). All resolved with lumbar drainage except for 1 EEA leak that required a reoperation.

CONCLUSIONS

Minimally invasive approaches for anterior and middle fossa skull base meningiomas require careful case selection. GTR rates are equally high for all approaches except for spheno-orbital meningiomas, where alleviation of proptosis and not GTR is the primary goal of surgery. New anosmia was most common after EEA.

The Evolution of Anterior Transpetrosal Approach for the Treatment of Petroclival Meningiomas: A Single-Center 128-Case Experience

BACKGROUND

The profound understanding of anterior transpetrosal approach (ATPA) is increasingly used to treat petroclival meningiomas (PCMs). We introduce the evolution of ATPA and the outcomes of PCMs treatment.

METHODS

Between January 2013 and December 2019, 128 patients with PCMs underwent surgery. According to tumor extension, we classified the 128 patients into 5 types (I-V), introduced key technologies of ATPA into different types for the first time, and achieved a supreme surgical technology. Clinical data, radiological findings, surgical treatments, complications, and patient outcomes were retrospectively analyzed.

RESULTS

A total of 22 (17.2%), 44 (34.4%), 25 (19.5%), 29 (22.7%), and 8 (6.3%) patients had type I, II, III, IV, and V disease, respectively. Tumors were gross totally removed (Simpson I and II) in 100 patients (78.1%), subtotally removed (Simpson III) in 20 patients (15.6%), and partially removed (Simpson IV) in 8 patients (6.3%). The progression or recurrence rates were 5% (5/100) for gross totally removed, 22.3% (6/20) for subtotally removed, and 62.5% (5/8; 1 died) for partially removed. According to the Karnofsky Performance Scale and Glasgow Outcome Scale, 108 patients had good recovery (84.4%, 108/128) and 115 were independent (89.8%, 115/128) at the end of follow-up.

CONCLUSIONS

Because some key technologies were used in ATPA, the application of ATPA was extended, and greater tumor resection and nerve function protection could be achieved in the treatment of PCMs.

The medial transorbital approach in cranioendoscopic skull base tumor resections for locally advanced tumors

BACKGROUND

Orbital structure preservation and avoidance of facial incisions without compromising oncological outcome are key to maintaining function and quality of life in locally advanced sinonasal tumor surgery. A transorbital approach at our institution has proven invaluable during cranioendoscopic skull base tumor resections and there are few descriptions of this in the literature.

METHODS

An IRB-approved retrospective chart review was conducted at a tertiary cancer center for patients between 2020 and 2022 undergoing cranioendoscopic tumor resections utilizing a transorbital approach. Data collected included histopathology, sinus origin, disease extent, stage, operative details, length of stay, neo-adjuvant treatment and adjuvant treatment. Recurrence, survival, and complication rates were assessed.

RESULTS

Four patients were identified for inclusion, including a SMARCB1-deficient carcinoma, esthesioneuroblastoma, squamous cell carcinoma and meningioma. All patients had resection of gross and microscopic disease with preservation of orbital contents. Post-operatively, one patient had mild diplopia on inferior gaze, all other patients had normal vision. Median follow-up was 9.5 months. One patient had recurrence of disease intracranially.

CONCLUSIONS

The cranioendoscopic approach with a medial transorbital incision has multiple benefits. It avoids the need for a Weber-Ferguson incision with associated facial scar, allows for early intra-operative assessment for orbital invasion using tactile feedback and safe dissection of disease while protecting the globe and rectus muscles. This leads to preservation of eye function while ensuring an oncological resection. Other advantages include ligation of the anterior ethmoid artery and access for reconstruction of the medial orbital wall.

[Convexity hyperostotic meningioma en plaque: a systematic review]

BACKGROUND

Planar hyperostotic meningiomas account for 2-9% of intracranial meningiomas. They are characterized by planar node following the contours of the inner surface of the skull. Hyperostosis is present in most cases. Timely diagnosis of skull base tumors is usually simple due to early involvement of the cranial nerves. However, convexity meningiomas en plaque usually reach large dimensions that complicates surgery and radiotherapy.

OBJECTIVE

To analyze the current state of diagnosis, molecular biology and surgical treatment of hyperostotic meningiomas en plaque.

MATERIAL AND METHODS

A systematic review was performed in accordance with the PRISMA guidelines. Searching for literature data included the following keywords: «planar meningioma», «hyperostotic meningioma», «meningioma en plaque», «infiltrative meningioma». We reviewed the PubMed and Google Scholar databases until May 2023 and enrolled only full-text Russian-, English- or French-language reports.

RESULTS AND DISCUSSION

Among primary 332 reports, 35 references met the inclusion criteria. We found less severity or absence of focal neurological symptoms, comparable incidence of intracranial hypertension and no histological differences between planar and nodular meningiomas. Analysis of molecular biological features of planar meningiomas, including cell cultures, is feasible. There is no consensus regarding surgical treatment and radiotherapy. Most publications are case reports.

CONCLUSION

The results of treatment of planar hyperostotic meningiomas, especially large and giant ones, are unsatisfactory. There is no a generally accepted algorithm for treating patients in the literature. This problem requires further research.

Extent of Surgical Resection as a Predictor of Tumor Progression in Skull Base Chordomas: A Multicenter Volumetric Analysis

INTRODUCTION

Skull-base chordomas are aggressive tumors with a propensity for recurrence/progression. Even with standard of care (SoC), 5-year recurrence rates are variable (19%-54%). This high recurrence/progression rate correlates with increased morbidity and mortality. We sought to analyze a multicenter cohort of skull base chordomas to identify predictors of progression in patients receiving SoC.

METHODS

The [Blinded]-Neurosurgery data registry was queried for skull base chordomas treated from 2008-2020. Patients with the histopathologic diagnosis of chordoma were included. The cohort was composed of patients with preoperative and postoperative magnetic resonance imaging. Tumor volume and radiologic characteristics were obtained from axial T2 sequences using a Digital Imaging and Communications in Medicine viewer. Survival analysis was performed using Kaplan-Meier method, and time-to-event multivariate regression was performed to identify independent predictors of progression.

RESULTS

The cohort included 195 patients, of which 66 patients met inclusion criteria; median age was 44, and 28 (42%) were females. Fifty-four (82%) received SoC, 7 (11%) resection only, and 5 (8%) radiotherapy only. Median preoperative and postoperative tumor volumes were 11.55 cm3 (0.33-54.89) and 0.34 cm3 (0-42.52), respectively. Recurrence rate with SoC was 37%. Postoperative tumor volume (P = 0.010) correlated with progression. A postoperative volume of >4.9 cm3 (P = 0.044), ≤81.3% of tumor resection (P = 0.02), and lower-clivus location (P < 0.005) correlated with decreased time to progression.

CONCLUSIONS

Skull base chordomas can be challenging to resect. Even though maximal resection and radiotherapy improve rate of tumor progression, many of these lesions eventually recur. We have identified a postoperative tumor volume of ≥4.9 cm3 and extent of resection of ≤81.3% in this cohort as predictors of progression in patients receiving SoC.

Variability in the Arterial Supply of Intracranial Meningiomas: An Anatomic Study

BACKGROUND AND OBJECTIVES

Intracranial meningiomas are a diverse group of tumors, which vary by grade, genetic composition, location, and vasculature. Expanding the understanding of the supply of skull base (SBMs) and non-skull base meningiomas (NSBMs) will serve to further inform resection strategies. We sought to delineate the vascular supply of a series of intracranial meningiomas by tumor location.

METHODS

A retrospective study of intracranial meningiomas that were studied using preoperative digital subtraction angiograms before surgical resection at a tertiary referral center was performed. Patient, tumor, radiologic, and treatment data were collected, and regression models were developed.

RESULTS

One hundred sixty-five patients met inclusion criteria. The mean age was 57.1 years (SD: 12.6). The mean tumor diameter was 4.9 cm (SD: 1.5). One hundred twenty-six were World Health Organization Grade I, 37 Grade II, and 2 Grade III. Arterial feeders were tabulated by Al-Mefty's anatomic designations. SBMs were more likely to derive arterial supply from the anterior circulation, whereas NSBMs were supplied by external carotid branches. NSBMs were larger (5.61 cm vs 4.45 cm, P = <.001), were more often presented with seizure (20% vs 8%, P = .03), were higher grade ( P = <.001) had more frequent peritumoral brain edema (84.6% vs 66%, P = .04), and had more bilateral feeders (47.7% vs 28%, P = .01) compared with SBMs. More arterial feeders were significantly associated with lower tumor grade ( P = .023, OR = 0.59). Higher tumor grade (Grade II/III) was associated with fewer arterial feeders ( P = .017, RR = 0.74).

CONCLUSION

Meningioma location is associated with specific vascular supply patterns, grade, and patient outcomes. This information suggests that grade I tumors, especially larger tumors, are more likely to have diverse vascular supply patterns, including internal carotid branches. This study may inform preoperative embolization and surgical considerations, particularly for large skull base tumors.

Radical resection of intracavernous chondrosarcoma using an intradural keyhole approach: how I do it

BACKGROUND

Skull base chondrosarcoma is rare, arising from the clivus or petroclival junction, and usually presents as ocular motility disorders. Endonasal transsphenoidal surgery may be performed in some cases of midline clivus chondrosarcoma. Chondrosarcoma is located within the cavernous sinus and presents a softer/gelatinous mass and can be removed with suctions and curettage. We have been using a simple intradural keyhole transcavernous approach, avoiding a complex extradural transcavernous dissection.

METHODS

The intracavernous chondrosarcoma was removed via a 5 mm keyhole opening over the Parkinson's triangle using a standard frontotemporal intradural approach.

CONCLUSION

Minimally invasive keyhole surgical resection can be performed to eradicate skull base chondrosarcomas, avoiding complex extradural cranial base approaches.

Does tumoral cavernous carotid stenosis predict an increased risk of future stroke in skull base meningiomas?

OBJECTIVE

Skull base meningiomas (SBMs) involving the cavernous sinus encase the internal carotid artery (ICA) and may lead to stenosis of the vessel. Although ischemic stroke has been reported in the literature, there are to the authors' knowledge no reported studies quantifying the risk of stroke in these patients. The authors aimed to determine the frequency of arterial stenosis in patients with SBMs that encase the cavernous ICA and to estimate the risk of ischemic stroke in these patients.

METHODS

Records of all patients with SBM encasing the ICA whose cases were managed by the skull base multidisciplinary team at Salford Royal Hospital between 2011 and 2017 were reviewed using a two-stage approach: 1) clinical and radiological strokes were identified from electronic patient records, and 2) cases were reviewed to examine the correlation between ICA stenosis associated with SBM encasement and anatomically related stroke. Strokes that were caused by another pathology or did not occur in the perfusion territory were excluded.

RESULTS

In the review of patient records the authors identified 118 patients with SBMs encasing the ICA. Of these, 62 SBMs caused stenosis. The median age at diagnosis was 70 (IQR 24) years, and 70% of the patients were female. The median follow-up was 97 (IQR 101) months. A total of 13 strokes were identified in these patients; however, only 1 case of stroke was associated with SBM encasement, which occurred in the perfusion territory of a patient without stenosis. Risk of acute stroke during the follow-up period for the entire cohort was 0.85%.

CONCLUSIONS

Acute stroke in patients with ICA encasement by SBMs is rare despite the propensity of these tumors to stenose the ICA. Patients with ICA stenosis secondary to their SBM did not have a higher incidence of stroke than those with ICA encasement without stenosis. The results of this study demonstrate that prophylactic intervention to prevent stroke is not necessary in ICA stenosis secondary to SBM.

A brief review of skull base chordomas

Skull base chrodomas are slow growing neoplasms usually located along the midline. They display a locally invasive nature with possibilities of extracranial metastasis. Presentation is usually late and depends upon the location and extent of the tumour. Management aims at gross total resection via open microsurgical or endoscopic approach followed by adjuvant radiotherapy. Prognosis may be good for the classical and chondroid subtypes but remains poor for de-differentiated type.

Dermoid cyst of the infratemporal fossa: a case report of surgical resection by infratemporal fossa type B approach

OBJECTIVE

This is a case report of a dermoid cyst located in the infratemporal fossa and its surgical removal using infratemporal fossa type B approach.

CASE REPORT

A 15-year-old male was referred from a local clinic after an incidental finding of a mass lesion in the skull base area on computed tomography (CT). Pre-operative magnetic resonance imaging showed a large cystic mass lesion, expanding to the foramen ovale with fat component in the right infratemporal fossa region. The lesion was completely excised using an infratemporal fossa type B approach.

CONCLUSION

An extremely rare case of dermoid cysts of the infratemporal fossa was managed with infratemporal fossa type B approach without severe complication.

Endoscopic Endonasal Approach for Tuberculum Sellae Meningioma: 2-Dimensional Operative Video

INDICATIONS CORRIDOR AND LIMITS OF EXPOSURE

Ideal indications for tuberculum sellae meningiomas (TSM) removal through endoscopic endonasal approach (EEA) are midline tumors (<3.5 cm), possibly with no optic canal invasion and no vessels encasement. The EEA is favored by a wide tuberculm sellae (TS) angle and a deep sella at the sphenoid sinus (SS). 1 Adequate removal of paranasal structures provides a wider surgical corridor ensuring exposure at the suprasellar area and safe instruments manuevrability. 2.

ANATOMIC ESSENTIALS NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT

The endoscopic transtuberculum transplanum approach allows for wide suprasellar intradural exposure. 3 Removal of the supraoptic recess (SOR) provides further lateral extension over the planum sphenoidale (PS) and proper management of dural involvement at the optic canal. 4.

ESSENTIAL STEPS OF THE PROCEDURE

The patients have consented to the procedure. Bone removal starts at the upper sella and TS and is extended anteriorly over the PS and laterally, upon needs, at the SORs. On dural opening, tumor devascularization, dedressing, debulking, and dissection are run. Skull base reconstruction is performed using the 3F technique. 5.

PITFALLS/AVOIDANCE OF COMPLICATIONS

In those cases with vessel encasement, possibility of achieving total resection has to be balanced with risk of vascular injury. 6 Optic canal dural invasion precludes tumor total removal; however, bony decompression is maximal using the EEA. Concerning postoperative cerebrospinal fluid fistula, nowadays the rates have dropped to <2%.

VARIANTS AND INDICATIONS FOR THEIR USE

A wider skull base osteodural opening allows for the removal of selected meningiomas extending to the PS and cribriform plate.

Endoscopic Transpterygoid Corridor for Petroclival Tumors: Case Series and Technical Nuances

Background

The petroclival area is a technically challenging region to operate owing to the proximity of the internal carotid artery (ICA) and the need to obtain gross total excision of tumors in this area as they are often resistant to radiotherapy.

Objective

We present our experience with the endonasal endoscopic transpterygoid approach in managing tumors of the petroclival region and discuss various operative nuances for safer resection.

Materials and Methods

A retrospective study of all consecutive cases of lesions occupying the petroclival region that were operated via endonasal endoscopic transpterygoid approach at our center between January 2016 and December 2021 was performed.

Results

The study included 14 cases of lesions occupying the petroclival region. Gross total resection by intraoperative observation was achieved in 10 patients, near total decompression was performed in two patients, and the remaining two patients underwent marsupialization of lesion. Postoperatively, one patient had right Lower motor neuron (LMN) facial nerve palsy and one patient required surgery for Cerebrospinal fluid (CSF) rhinorrhea on postoperative day 8. The mean duration of follow-up was 13.8 ± 16.6 months (range: 2-59 months). Four of six patients with visual symptoms on presentation reported improvement in vision, and the other two patients had a stable vision on follow-up. Two patients received radiotherapy postsurgery. No mortality was noted.

Conclusion

The extended endonasal endoscopic transpterygoid approach can be safely and efficiently used for petroclival lesions. Very sound knowledge of anatomical relationship, use of intraoperative image guidance to avoid injury to ICA, and multilayer reconstruction with a vascularized nasoseptal flap are required to optimize the clinical outcome.

Combined and staged retrosigmoid, extended middle fossa, and endoscopic transnasal approach to a petroclival chondrosarcoma: how I do it

BACKGROUND

Tumors of the petroclival region with multicompartment extension can be difficult to address with a single surgical approach.

METHOD

We present the case of a patient with a large chondrosarcoma centered at the right petroclival fissure with extension into the cavernous sinus, the region beneath the cavernous sinus, cerebellopontine angle with deformation of the pons, and prevertebral space. A staged complete resection was performed using a stage 1 single-incision combined right retrosigmoid craniotomy and extended middle fossa craniotomy, followed by a stage 2 endoscopic transnasal approach.

CONCLUSION

A combined approach to selected petroclival tumors can maximize safe resection.

Multiple approaches to a spheno-orbital and deep face meningioma: how I do it

BACKGROUND

The integration of multiple approaches is sometimes needed for the safe resection of complex multicompartment skull base tumors.

METHOD

We present the case of a spheno-orbital and deep face meningioma that required a staged resection strategy using transnasal, transoral, transfacial, and transcranial approaches for airway protection and maximal safe tumor removal.

CONCLUSION

Limitations in individual skull base approaches for complex tumors can be anticipated and overcome by combining approaches.

Giant Cell Tumor of the Temporal Bone and Skull Base

Giant cell tumor (GCT) is a benign tumor that originates from undifferentiated mesenchymal cells of the bone marrow. The craniums as well as temporal bone are extremely rare locations for GCTs. Clinical, radiological, and anatomical diagnosis of this locally aggressive disease poses a major challenge in clinical practice. In this article, we present a clinical study for a 35-year-old female who was found to have left-sided temporal bone GCT with extension to middle cranial fossa and temporomandibular joint (TMJ) with its clinical features and management.

Combined retrosigmoid and middle fossa approach for a small, superiorly located petroclival meningioma: how I do it

BACKGROUND

Petroclival meningiomas pose significant surgical challenges because of their deep location and complex surrounding neurovasculature. The use of multiple surgical approaches can optimize safe tumor removal from multiple anatomic compartments.

METHOD

We describe a patient with a growing superior petroclival meningioma centered at the posterior clinoid with extension into Meckel's cave that was successfully removed with a combined retrosigmoid and subtemporal middle fossa approach. This strategy avoided the need for anterior petrous bone drilling and tentorial splitting.

CONCLUSION

A combined retrosigmoid and subtemporal middle fossa approach can provide safe access to tumors spanning the supra- and infratentorial compartments.

Endoscopic Extended Transsphenoidal Surgery Aiming for Radical Resection of Skull Base Tumors Involving Cavernous Sinus: Assessment of Resectability and Risks of Complications

BACKGROUND AND OBJECTIVES

Surgical resection of tumors invading the cavernous sinus (CS) still shows therapeutic challenges. For "nonadenomatous" skull base tumors invading in CS, there were only a few reports showing the outcomes of radical resection. Therefore, the outcomes of endoscopic transsphenoidal surgery (ETS) aiming for radical resection thus remain largely unknown regarding resectability and functional results of the cranial nerves.

METHODS

We performed ETS aiming for radical resection in 35 skull base tumors involving CS (17 chondrosarcomas, 12 chordomas, 3 meningiomas, and 3 trigeminal schwannomas; median follow-up 36.5 months ranging from 12 to 91 months). Gross total resection (GTR) is attempted in all the cases for real-time findings from electrophysiological monitoring of the cranial nerves. When the tumor was strongly adherent to the cranial nerves or internal carotid artery, maximum volume reduction of the tumor was attempted.

RESULTS

GTR was achieved in 28 patients (80.0%), subtotal resection in 3 (8.6%), and partial resection in 4 (11.4%). One patient experienced internal carotid artery injury during surgery. After ETS, 15 patients showed symptom improvement (51.7% in all 29 patients with preoperative cranial nerve symptoms, CNS). Four (11.4%) transiently developed abducens nerve palsy, and one required repair surgery for cerebrospinal leakage. In univariate analyses, extension to the lateral compartment of CS ( P = .04) was significantly associated with reduced achievement of GTR. Previous transcranial surgery was associated with reduced possibility of improvement and worsening in CNS. Eleven patients underwent stereotactic radiosurgery, at a median of 12 months after ETS. 32 patients (91.4%) did not show recurrence at the final follow-up.

CONCLUSION

ETS can achieve sufficient surgical resection in most of the patients, with acceptable neurological complications. For patients with CNS, ETS may offer the opportunity for improving CNS. We should also always prioritize avoidance of critical situations by preventing internal carotid artery injury.

Anatomical variations and flow alterations of the uncal vein and its clinical implications in petroclival meningiomas

BACKGROUND

The Uncal vein (UV), downstream of the deep middle cerebral vein (DMCV), has a similar drainage pattern to the superficial middle cerebral vein (SMCV) and may be involved in venous complications during the anterior transpetrosal approach (ATPA). However, in petroclival meningioma (PCM), where the ATPA is frequently used, there are no reports evaluating drainage patterns of the UV and the risk of venous complications associated with the UV during the ATPA.

METHODS

Forty-three patients with petroclival meningioma (PCM) and 20 with unruptured intracranial aneurysm (control group) were included. Preoperative digital subtraction angiography was used to evaluate UV and DMCV drainage patterns on the side of the tumor and bilaterally in patients with PCM and the control group, respectively.

RESULTS

In the control group, the DMCV drained to the UV, UV and BVR, and BVR in 24 (60.0%), eight (20.0%), and eight (20.0%) hemispheres, respectively. Conversely, the DMCV in the patients with PCM drained to the UV, UV and BVR, and BVR in 12 (27.9%), 19 (44.2%), and 12 (27.9%) patients, respectively. The DMCV was more likely to be drained to the BVR in the PCM group (p < 0.01). In three patients with PCM (7.0%), the DMCV drained only to the UV, and furthermore, the UV drained to the pterygoid plexus via the foramen ovale, posing a risk for venous complications during the ATPA.

CONCLUSIONS

In the patients with PCM, the BVR functioned as a collateral venous pathway of the UV. Preoperative evaluation of the UV drainage patterns is recommended to reduce venous complications during the ATPA.

Imaging of pediatric calvarial and skull base tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee/ASPNR White Paper

A standardized imaging protocol for pediatric oncology patients is essential for accurate and efficient imaging, while simultaneously promoting collaborative understanding of pathologies and radiologic assessment of treatment response. The objective of this article is to provide standardized pediatric imaging guidelines and parameters for evaluation of tumors of the pediatric orbit, calvarium, skull base, and temporal bone. This article was drafted based on current scientific literature as well as consensus opinions of imaging experts in collaboration with the Children's Oncology Group Diagnostic Imaging Committee, Society of Pediatric Radiology Oncology Committee, and American Society of Pediatric Neuroradiology.

3D printing as surgical planning and training in pediatric endoscopic skull base surgery - Systematic review and practical example

BACKGROUND

Pediatric endoscopic skull base surgery is challenging due to the intricate anatomy of the skull base and the presence of tumors with varied pathologies. The use of three-dimensional (3D) printing technologies in skull base surgeries has been found to be highly beneficial. A systematic review of the literature was performed to investigate the published studies that reported the effectiveness of 3D printing in pediatric endoscopic skull base surgery.

METHODS

Pub Med, Embase, Science Direct, The Cochrane Library, and Scopus were searched from January 01, 2000, until June 30, 2022. Original articles of any design reporting on the effectiveness of 3D printing in pediatric endoscopic skull base surgery were included. Information related to study population, conditions, models used, and key findings of study were extracted. Quality of included studies was evaluated using the Joanna Briggs Institute's (JBI) Critical Appraisal Checklist for Studies. To exemplify the use of 3D technology in this scenario, we report a complex clival chordoma case.

RESULTS

Six research articles were retrieved and included for qualitative analysis. Four of the six studies were conducted in the United States, followed by two in China. According to these studies, 3D reconstruction and printed models were more beneficial than CT/MRI images when discussing surgery with patients. In clinical training, these models were more helpful than 2D images in understanding the pathology when used in conjunction with image-guiding systems. It has been found that patient-specific 3D modeling, simulations, and rehearsal are the most efficient preoperative planning techniques, particularly in the pediatric population, for the treatment of complicated skull base surgeries. All the studies had a moderate risk of bias.

CONCLUSION

3D printing technologies assist in printing complex skull base tumors and the structures around them in three dimensions at the point of care and at the time needed, enabling the choice of the appropriate surgical strategy, thus minimizing surgery-related complications.

A 13-year patient journey of infant giant clival chordoma: case report and literature review

Chordomas are rare malignant bone tumours that develop from the ectopic remnants of the embryonic notochord. In contrast to adults, the majority in children under 16 present intra-cranially (63%). In 2006, we reported the youngest case of a large clival chordoma, a 15-week old baby, the second case to present without skull base involvement and the fourth case of chordoma in a patient with tuberous sclerosis (TS) Kombogiorgas (Childs Nerv Syst 22(10):1369-1374, 2006). In this report, we provide an update on this patient's journey through a range of therapeutic options and summarize an update of the literature, since 2006, for this patient group.

“Endoscope-assisted Anterolateral Approach for a Craniovertebral Junction Chordoma”

Chordomas of craniovertebral junction represent a challenging pathology for neurosurgeons, due to their deep location, proximity with critical neurovascular structures and local aggressiveness. Several surgical options are available for these tumors: both endoscopic extended approaches and open approaches. We present the case of a 24 years old female with a craniovertebral junction chordoma with anterior and right lateral extension. For this case, an anterolateral approach with endoscopic assistance was chosen. Key surgical steps are presented. In the postoperative course the neurological symptoms improved and there were no complications. Unfortunately, she had an early recurrence of tumor two months later, prior the beginning of radiotherapy. After multidisciplinary consultation, we performed a second surgical removal and a posterior cervical spine arthrodesis. The anterolateral approach is a valuable option for craniovertebral junction chordomas with lateral extension and the endoscope assistance allowed to reach the narrowest and furthermost points. The patients must be referred to multidisciplinary skull base surgery centers and be addressed to early adjuvant radiation therapy.

Imaging of Skull Base Tumors

OBJECTIVE

This article provides an overview of imaging modalities and findings associated with common skull base tumors including meningiomas and how to use imaging features to guide surveillance and treatment decision making.

LATEST DEVELOPMENTS

Ease of access to cranial imaging has led to a higher number of incidentally diagnosed skull base tumors, which merit careful consideration for management with observation or treatment. The point of origin of the tumor dictates the pattern of anatomic displacement and involvement by the tumor as it grows. Careful study of vascular encroachment on CT angiography, as well as the pattern and extent of bony invasion on CT, abets treatment planning. Quantitative analyses of imaging, such as with radiomics, may further elucidate phenotype-genotype associations in the future.

ESSENTIAL POINTS

Combinatorial application of CT and MRI analyses improves the diagnosis of skull base tumors, clarifies their point of origin, and dictates the extent of treatment needed.

Resection of Condylar Skull Base Tumor via Combined Far Lateral and Infrajugular Approaches with Single-Stage Occipitocervical Fusion

Epithelioid hemangioma is a rare vascular mesenchymal tumor with a paucity of reports of cranial involvement. In particular, guidance on treatment for lateral skull base lesions is lacking, despite this being a highly technically challenging location. Nuances in the management decisions for this tumor type are discussed. Two major challenges with this location are proximity to critical neurovascular structures and managing secondary craniocervical instability. We present a patient with a lateral skull base epithelioid hemangioma treated with transcondylar resection, single-stage occipitocervical fusion, and adjuvant radiation and chemotherapy. The patient consented to both the procedure and the published report of her case including imaging. Obtaining tissue was necessary for diagnosis. Maximal safe resection, resection of a tumor such that the greatest clinical benefit is achieved with the minimum risk, was favored given the location and vascularity of the lesion. Occipitocervical fusion was recommended given ongoing bony destruction by the tumor and further expected iatrogenic instability upon resection. This was performed as a single stage given expected need for postoperative adjuvant radiation therapy and dynamic neck pain (Video 1). Surgical planning and decision making are detailed, including rationale and potential risks and benefits. We discuss positioning, equipment needs, and the importance of a multidisciplinary surgical team. Park bench positioning was used for part 1, left-sided extended far lateral and infratemporal fossa presigmoid approaches. For part 2, occipitocervical fusion, the patient was transitioned to prone position. The anatomy is highlighted in labeled pictures of the approach and dissection, and surgical video is presented for key surgical steps. Preoperative and postoperative imaging is analyzed. A desirable clinical outcome was obtained.

[Anterior transpetrosal (Kawase) approach for petroclival meningioma with trigeminal neuralgia: case report and literature review]

The authors present a patient with petroclival meningioma complicated by trigeminal neuralgia. Resection of tumor via anterior transpetrosal approach with microvascular decompression of the trigeminal nerve was performed. A 48-year-old female patient presented with left-sided (V1-V2) trigeminal neuralgia. Magnetic resonance imaging revealed a tumor 33´27´25 mm with a base adjacent to the top of petrous part of the left temporal bone, tentorium cerebelli and clivus. Intraoperative examination revealed true petroclival meningioma extending to trigeminal notch of petrous part of temporal bone. There was additional compression of trigeminal nerve by caudal branch of superior cerebellar artery. Total resection of tumor was followed by disappearance of vascular compression of trigeminal nerve and regression of trigeminal neuralgia. Anterior transpetrosal approach provides early devascularization and resection of true petroclival meningioma, as well as wide imaging of anterolateral surface of the brainstem, identification of neurovascular conflict and vascular decompression.

[Endoscopic transnasal resection of clival meningiomas]

Treatment of clival meningiomas is still one of the unresolved issues in modern neurosurgery. There are several treatment strategies. These ones include various combinations of follow-up, surgical CSF drainage, tumor resection and radiotherapy.

OBJECTIVE

To assess postoperative outcomes in patients with clival meningiomas.

MATERIAL AND METHODS

We analyzed 18 patients with large or giant clival meningiomas.

RESULTS

We assessed extent of resection using the scale by G. Frank and E. Pasquini (2002): total resection - 95-100%, subtotal - 80-95%, partial - 50-80%, extended biopsy - <50% of tumor. Total resection was achieved in 1 patient (5.5%), subtotal - 5 (27.8%), partial - 12 (66.7%). At the same time, brainstem decompression and regression of hydrocephalus were observed in all cases. Fourteen patients were followed-up. Median follow-up was 8.5 months. Seventeen patients underwent radiotherapy due to predominant partial and subtotal resection. Total focal dose ranged from 50 to 57 Gy in standard fractionation mode. None patient had residual tumor enlargement throughout the follow-up period. There were no lethal outcomes.

CONCLUSION

Endoscopic transnasal access to clival meningiomas in appropriate anatomical features of tumor and surrounding structures is a full-fledged alternative to transcranial treatment in these patients. This approach provides total resection and brainstem decompression. These facts increase life expectancy without deterioration of the quality of life.

Tuberculum Sellae Meningioma: Report of Two Cases and Literature Review of Limits of the Transcranial and Endonasal Endoscopic Approaches

BACKGROUND

Tuberculum sellae (TS) meningioma is one of the most frequent meningiomas of the anterior skull base. Herein we perform a review of the literature concerning the preferred surgical approaches to TS meningiomas; in addition, we describe two explicative cases, operated on by our group using different approaches, with the aim to critically revise surgical indications and contraindications.

METHODS

In October 2021, two female patients with tuberculum sellae meningioma were treated at the Policlinico Gemelli of Rome. The patients presented with visual deterioration. Surgery was performed using the fronto-temporal approach and transsphenoidal approach. The visual function before and after surgery was evaluated as the main outcome parameter of the surgical treatment of these tumors.

CONCLUSIONS

Tuberculum sellae meningioma can be safely resected using the transcranial approach and the transsphenoidal endoscopic approach with preservation and even improvement of visual function after surgery. The relationship of the tumor with the optic nerves, optic canal, and anterior cerebral artery complex are important issues that have to be considered when dealing with tuberculum sellae meningioma. Both transcranial and endonasal approaches, in experienced hands, can allow complete resection of the lesion.

[Bone defect closure after resection of sphenoorbital meningioma]

Sphenoorbital meningiomas (SOM) are a subgroup of skull base tumors with soft tissue component in the orbit and anterior and/or middle cranial fossa. According to different authors, SOMs account for 2-12% of all intracranial meningiomas. Reconstruction of bone defects after resection of SOM has own nuances. Along with cranial vault repair, patients encounter with cosmetic defects following facial skull lesion, ophthalmic symptoms due to orbital defects, dental and functional problems associated with opening of the mouth in case of damage to maxilla and mandible. Predominant infiltrative growth of tumor and common large bone defects involving various anatomical regions require multiple implants or implants with complex shape. Moreover, contact of implantation area with nasal cavity and paranasal sinuses requires additional impermeability of soft tissue reconstruction and inertness of materials.

OBJECTIVE

To summarize available modern data on bone defect closure after resection of SOM.

MATERIAL AND METHODS

The authors reviewed available data on bone defect closure after resection of SOM. Effectiveness of modern methods of reconstruction and safety of materials were assessed.

RESULTS

We analyzed 96 available references. Technical features of tumor resection, materials used for bone defect closure and modern possibilities of 3D technologies in reconstructive surgery were described. The authors proposed the algorithms for selecting the materials for bone defect closure after resection of SOM.

CONCLUSION

Improvement of surgical technique and development of new materials and technologies significantly improve cosmetic and functional results. A large percentage of negative ophthalmologic outcomes and high risk of complications in SOM surgery require further studies and elaboration of modern techniques.

Surgical management of skull base meningiomas and vestibular schwannomas

PURPOSE OF REVIEW

The aim of this study is to discuss surgical management of meningiomas and schwannomas of skull base.

RECENT FINDINGS

Meningiomas and schwannomas are typically benign neoplasm with a good prognosis after surgery. Patients should be treated individually related to several features: size and localization of tumor and its proximity with deep critical neurovascular structures, neurological status, age and comorbidity. Also, the widespread use of neuroimaging and the progressive and constant aging of the populations inevitably result in the increase of detection rate of incidental (asymptomatic) neoplasm.Nowadays, there are still controversies about the correct management strategy.

SUMMARY

Surgery represents the gold standard treatment, with the objective of gross total resection; however, it is not always feasible due to localization, encasement of neuro-vascular structure, invasion of cranial nerve and brain parenchyma. Stereotactic radiosurgery and radiation therapy are important to achieve a satisfactory functional outcome and tumor control in case of residue or recurrence. A multidisciplinary approach is pivotal.

Differentiation of Skull Base Chondrosarcomas, Chordomas, and Metastases: Utility of DWI and Dynamic Contrast-Enhanced Perfusion MR Imaging

BACKGROUND AND PURPOSE

Differentiation of skull base tumors, including chondrosarcomas, chordomas, and metastases, on conventional imaging remains a challenge. We aimed to test the utility of DWI and dynamic contrast-enhanced MR imaging for skull base tumors.

MATERIALS AND METHODS

Fifty-nine patients with chondrosarcomas, chordomas, or metastases between January 2015 and October 2021 were included in this retrospective study. Pretreatment normalized mean ADC and dynamic contrast-enhanced MR imaging parameters were calculated. The Kruskal-Wallis H test for all tumor types and the Mann-Whitney U test for each pair of tumors were used.

RESULTS

Fifteen chondrosarcomas (9 men; median age, 62 years), 14 chordomas (6 men; median age, 47 years), and 30 metastases (11 men; median age, 61 years) were included in this study. Fractional plasma volume helped distinguish all 3 tumor types (P = .003, <.001, and <.001, respectively), whereas the normalized mean ADC was useful in distinguishing chondrosarcomas from chordomas and metastases (P < .001 and P < .001, respectively); fractional volume of extracellular space, in distinguishing chondrosarcomas from metastases (P = .02); and forward volume transfer constant, in distinguishing metastases from chondrosarcomas/chondroma (P = .002 and .002, respectively) using the Kruskal-Wallis H test. The diagnostic performances of fractional plasma volume for each pair of tumors showed areas under curve of 0.86-0.99 (95% CI, 0.70-1.0); the forward volume transfer constant differentiated metastases from chondrosarcomas/chordomas with areas under curve of 0.82 and 0.82 (95% CI, 0.67-0.98), respectively; and the normalized mean ADC distinguished chondrosarcomas from chordomas/metastases with areas under curve of 0.96 and 0.95 (95% CI, 0.88-1.0), respectively.

CONCLUSIONS

DWI and dynamic contrast-enhanced MR imaging sequences can be beneficial for differentiating the 3 common skull base tumors.