Clivus Hemangioma in a Pediatric Patient: Case Report.

BACKGROUND: Hemangiomas are benign blood vessels tumors that represent less than 1% of all the bone neoplasms. Calvarial hemangiomas are mainly solitary lesions commonly located in the frontal and parietal bone; however, they may occur in any skull region. These tumors increase in size over a period of months to years before they start showing their first symptoms such as headache, bone deformity, and pathological fractures. Differential diagnosis with osteosarcoma should be considered. Surgical resection with a safety margin is a standard treatment of the cranial hemangioma. Furthermore, radiotherapy has proven to stop the tumor's growth but not its size. CASE DESCRIPTION: We treated an 11-year-old male who had a rare case of a capillary hemangioma located in the clivus bone. The patient underwent 2 endoscopic endonasal resection because of tumor recurrence. Surgical safety margins are highly recommended, but this procedure could not be performed because of the tumor's location. After the second relapse, the oncology team decided to initiate radiotherapy. At 6-month follow-up, the tumor reduced its size and remained unchanged. CONCLUSIONS: Surgical safety margins are highly important to prevent recurrence in this type of bone tumors. Skull base hemangiomas are a big challenge when you want to achieve these safety margins. We believe that a combined treatment of surgery and radiotherapy should be considered as the main treatment.

High Expression of TGF-ß1 Predicting Tumor Progression in Skull Base Chordomas.

OBJECTIVE: To investigate the expression characteristics and prognostic value of transforming growth factor ß1 (TGF-ß1) in primary skull base chordomas (SBCs). METHODS: The mRNA expression levels of TGF-ß1 were measured in 57 frozen samples from patients with primary SBCs. Clinical data collection, follow-up, correlations, and survival analyses were performed. RESULTS: In the series of 57 patients (29 men and 28 women) with primary SBCs, the mean value of TGF-ß1 mRNA was 1.713 with a median of 0.904. Twenty-four SBCs were soft type and 33 were hard type. The Mann-Whitney U test revealed that the expression level of TGF-ß1 mRNA in hard type SBCs was significantly higher than the expression level found in the soft type (P = 0.03). The independent-samples median test suggested that the expression level of TGF-ß1 mRNA in female patients' SBCs was significantly higher than that in male patients' SBCs (P = 0.01). Expression differences of TGF-ß1 were not seen among different pathological subtypes, tumor blood supply, or degree of resection. The Spearman rank correlation coefficient clarified that TGF-ß1 mRNA levels were not correlated with tumor diameter, preoperative Karnofsky Performance Status (KPS), postoperative KPS, follow-up KPS, age, or intraoperative blood loss. The multivariate Cox analysis revealed that pathological subtype (P = 0.008), expression level of TGF-ß1 mRNA (P = 0.01), and tumor texture (P = 0.03) were all independent prognostic factors for tumor progression. CONCLUSIONS: SBCs in female patients and SBCs with hard texture were prone to have high TGF-ß1 mRNA expression. High expression of TGF-ß1, hard tumor texture, and conventional subtype were all independent risk factors for tumor progression.

Septal floor rotational flap pedicled on ethmoidal arteries for endoscopic skull base reconstruction.

OBJECT: Expanded endonasal approaches have dramatically changed how skull base surgery is performed, and nasoseptal flap (NSF) has significantly improved skull base reconstruction. However, challenges remain when the pterygopalatine artery is invaded by tumors; when it must be sacrificed to approach the lateral sphenoidal recess; when late-occurrence leak occurs in the sella after transsphenoidal surgery; and also when the leak is on the posterior wall of the frontal sinus, which is too distant for NSF to reach. This article describes a septal floor rotational flap pedicled on ethmoidal arteries for endoscopic skull base reconstruction in certain cases. STUDY DESIGN: Case series. METHOD: In this article, we retrospectively review a series of 19 patients who underwent skull base reconstruction with a septal floor rotational flap pedicled on the ethmoidal arteries. RESULT: All 19 flaps, including the anterior and posterior artery pedicled flaps, survived without significant complications, and no postoperative cerebrospinal fluid leak occurred during follow-up. CONCLUSION: Ethmoidal arteries pedicled septal floor rotational flap, with their strong blood supply and large coverage area, are ideal replacements for NSF. These flaps are qualified in locations ranging from the posterior wall of the frontal sinus to the lateral sphenoidal recess and in cases ranging from tumor invading the pterygopalatine fossa to sellar late-occurred leak after transsphenoidal surgery. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:2696-2701, 2019.

Implications of Extracranial Distortion in Ultra-High-Field Magnetic Resonance Imaging for Image-Guided Cranial Neurosurgery.

BACKGROUND: Ultra-high-field magnetic resonance imaging (MRI) of the brain is attractive for image guidance during neurosurgery because of its high tissue contrast and detailed vessel visualization. However, high-field MRI is prone to distortion artifacts, which may compromise image guidance. Here we investigate intra- and extracranial distortions in 7-T MRI scans. METHODS: Five patients with and 5 patients without skin-adhesive fiducials received magnetization-prepared T1-weighted 7-T MRI and standard 3-T MRI scans. The 7- and 3-T images were rigidly coregistered and compared. Intracranial distortions were evaluated qualitatively, whereas shifts at the skin surface and shifts of the center positions of skin-adhesive fiducials were measured quantitatively. Moreover, we present an illustrative case of an ultra-high-field image-guided skull base meningioma resection. RESULTS: We found excellent intracranial correspondence between 3- and 7-T MRI scans. However, the average maximum skin shift was 6.8 ± 2.0 mm in group A and 5.2 ± 0.9 mm in group B. The average maximum difference between the skin-adhesive fiducial positions was 5.6 ± 3.1 mm in group B. In our tumor resection case, the meningioma blood supply could be targeted early thanks to 7-T image guidance, which made subsequent tumor removal straightforward. CONCLUSIONS: There are no visible intracranial distortions in magnetization-prepared T1-weighted 7-T MRI cranial images. However, we found considerable extracranial shifts. These shifts render 7-T images unreliable for patient-to-image registration. We recommend performing patient-to-image registration on a routine (computed tomography scan or 3-T magnetic resonance) image and subsequently fusing the 7-T magnetic resonance image with the routine image on the image guidance machine, until this issue is resolved.

Characterization of Skull Base Lesions Using Pseudo-Continuous Arterial Spin Labeling.

PURPOSE: Pseudo-continuous arterial spin labeling (pCASL) is a non-invasive magnetic resonance (MR) perfusion technique. Our study aimed at estimating the diagnostic performance of the pCASL sequence in assessing the perfusion of skull base lesions both qualitatively and quantitatively and at providing cut-off values for differentiation of specific skull base lesions. METHODS: In this study 99 patients with histopathologically confirmed skull base lesions were retrospectively enrolled. Based on a pathological analysis, the lesions were classified as hypervascular and non-hypervascular. Patients were divided into two subgroups according to the anatomical origin of each lesion. The MRI study included pCASL and 3D T1-weighted fat-saturated post-contrast sequences. Of the patients seven were excluded due to technical difficulties or patient movement. The lesions were classified by two raters, blinded to the diagnosis as either hyperperfused or non-hyperperfused, based on the pCASL sequence. The normalized tumor blood flow (nTBF) of each lesion was determined. Qualitative and quantitative characteristics of hypervascular and non-hypervascular lesions were compared. RESULTS: Visual assessment enabled correct classification of 98% of the lesions to be performed. Quantitatively, we found significant differences between the nTBF values for hypervascular and non-hypervascular lesions (p < 0.001) and provided cut-off values, allowing meningioma and schwannoma to be distinguished from meningioma and adenoma. Significant differences were also found within the hypervascular group, namely, paraganglioma was more hyperperfused than meningioma (p = 0.003) or metastases (p = 0.009). CONCLUSION: The present study demonstrates the high diagnostic performance of pCASL in characterizing skull base lesions by either visual assessment or nTBF quantification. Adding the pCASL sequence to the conventional protocol of skull base assessment can be recommended.

The Effect of Preoperative Direct Ligation of Ethmoidal Arteries on the Perioperative Outcomes of Large Anterior Skull Base Meningiomas Surgery: A Clinical Study.

BACKGROUND: Anterior skull base meningiomas often grow to a large size (≥4 cm) before detection. Their blood supply is mostly provided by the anterior and posterior ethmoidal arteries. Because of their vascularity, intraoperative bleeding can be a challenging prospect that increases the risk of perioperative complications. Preoperative ethmoidal arteries ligation has been used to aid in limiting blood loss. Our objective was to assess the effect of preoperative arterial ligation on the perioperative course of large (≥4 cm) to giant (≥6 cm) anterior skull base meningiomas. METHODS: We retrospectively searched our database for large anterior skull base meningiomas (≥4 cm). We analyzed differences in intraoperative blood loss, operative time, intraoperative transfusion, and hematologic parameters between patients who did not undergo preoperative ethmoidal arteries ligation (Group 1) and those who did (Group 2). RESULTS: Average estimated blood loss (EBL) was 825 mL (Group 1) versus 350 mL (Group 2) (P = 0.42), decrease in hemoglobin was 4 g/dL versus 3.2 g/dL (P = 0.53), decrease in hematocrit was 12.4% versus 9.6% (P = 0.64), and average operative time was 656 minutes versus 598 minutes (P = 0.58). EBL per volume yielded a ratio of 10.6 mL/cm3 versus 4.1 mL/cm3 (P = 0.06). CONCLUSIONS: Ethmoidal arteries ligation may have a benefit in large-to-giant anterior skull base meningiomas surgery. Our results showed a decrease in EBL and lesser decrease in pre- and postoperative hemoglobin and hematocrit levels as compared with cases in which no vascular ligation was performed when corrected for tumor volume.

The McConnell's Capsular Arteries and Their Relevance in Endoscopic Endonasal Approach to the Sellar Region.

BACKGROUND: The McConnell's capsular arteries (MCCA) were first described in 1953. They consist of medial branches of the cavernous internal carotid artery (ICA) and are divided in anterior and inferior capsular arteries. OBJECTIVE: To highlight the anatomy of the MCCA and its importance in the surgical treatment of tuberculum sellae and planum sphenoidale tumors through an endoscopic endonasal approach. METHODS: Ten cadaveric specimens fixed in formalin and perfused with colored silicone were dissected. Standard endoscopic endonasal transsphenoidal approach to the sellar region was performed. The MCCA were identified and still images were captured for further analysis. We report 1 case to illustrate the importance of the MCCA. RESULTS: The anterior capsular artery, which originates from the anteromedial aspect of the anterior loop of the cavernous ICA and reaches the suprasellar space, was present in 70% of the specimens with no difference between the right and left sides. The anterior capsular artery plays an important role in the vascularization of tuberculum sellae meningiomas. The inferior capsular artery originates from the inferomedial aspect of the cavernous ICA, at its horizontal portion, and reaches the floor and anterior wall of the sella where it anastomoses to branches of the inferior hypophyseal artery. CONCLUSION: The MCCA are key structures when performing an endoscopic endonasal approach for tumors of the sellar and suprasellar regions.

Evaluation of Venous Drainage Patterns for Skull Base Meningioma Surgery.

The evaluation of venous drainage patterns prior to surgery for skull base meningioma is important owing to their deep location and the vulnerability of surrounding vascular structures. In recent years, the microsurgical skull base approach has matured as a surgical technique, making it an important option for reducing complications related to skull base meningioma surgery. In addition, knowledge of the venous anatomy can prevent venous drainage route disturbance and potentially life-threatening complications. Hence, this topic review aimed to provide an overview of normal venous anatomy as it relates to the microsurgical skull base approach, discuss known changes in venous drainage routes that are associated with the progression of skull base meningioma and the selection of an appropriate operative approach with the highest likelihood of preserving venous drainage structures.

MR Imaging Grading System for Skull Base Chordoma.

BACKGROUND AND PURPOSE: Skull base chordoma has been widely studied in recent years, however, imaging characteristics of this tumor have not been well elaborated. The purpose of this study was to establish an MR imaging grading system for skull base chordoma. MATERIALS AND METHODS: In this study, 156 patients with skull base chordomas were retrospectively assessed. Tumor-to-pons signal intensity ratios were calculated from pretreatment MR images RT1 (ratio of tumor to pons signal intensity in T1 FLAIR sequence), RT2 (ratio of tumor to pons signal intensity in T2 sequence) and REN (ratio of tumor to pons signal intensity in enhanced T1 FLAIR sequence), and significant ratios for overall survival and progression-free survival were selected to establish a grading system. Clinical variables among different MR imaging grades were then analyzed to evaluate the usefulness of the grading system. RESULTS: RT2 (P < .001) and REN (P = .04) were identified as significant variables affecting progression-free survival. After analysis, the classification criteria were set as follows: MR grade I, RT2 > 2.49 and REN ≤ 0.77; MR grade II, RT2 > 2.49 and REN > 0.77, or RT2 ≤ 2.49 and REN ≤ 0.77; and MR grade III, RT2 ≤ 2.49 and REN > 0.77. MR grade III tumors had a more abundant tumor blood supply than MR grade I tumors (P < .001), and the intraoperative blood loss of MR grade III tumors was higher than that of MR grade I tumors (P = .002). Additionally, skull base chordoma progression risk increased by 2.071 times for every single MR grade increase (P < .001). CONCLUSIONS: A higher RT2 value was a negative indicator of tumor progression, whereas a higher REN value was a positive risk factor of tumor progression. MR grade III tumors showed a more abundant blood supply than MR grade I tumors, and the risk of skull base chordoma progression increased with every single MR grade increase.

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.

Cavernous sinus meningiomas: imaging and surgical strategy.

Cavernous sinus (CS) meningiomas which are by definition those meningiomas which originate from the parasellar region are difficult skull base tumors to deal with. For deciding the most appropriate surgical strategy, surgeons need detailed preoperative neuroimaging. The vicinity of the tumor with the vital and highly functional neurovascular structures, tumor extensions into the basal cisterns and skull base structures, and the arterial vascularization and venous drainage pathways, as they shape operative strategy, are important preoperative data to take into account. Thin section CT scan with bone windows, 3D spiral CT reconstruction, MRI, MR angiography, and DSA performed with selective arteriography including late venous phases give those required detailed informations about the tumor and its relation with neurovascular and bony structures. The type of craniotomy and complementary osteotomy and the usefulness of an extradural anterior clinoidectomy with unroofing the optic canal can be decided from preoperative neuroimaging. Data collected also help in determining whether extensive exposure of the middle cranial fossa is necessary to ensure substantial devascularization of the tumor and whether proximal control of the internal carotid artery (ICA) at its intrapetrosal portion might be useful. Study of the capacity of blood supply of the Willis circle is wise for deciding the need and way of performing an extra-intracranial bypass together with tumor removal. Currently the concept of operating only the tumors with extracavernous extensions and to limit resection to only their extracavernous portions is the most accepted way of treating these tumors. It was that strategy that was adopted in the senior author's 220-patient series.Radiosurgery or stereotactic fractionated radiotherapy may complement surgery or can be only reserved for growing remnants.

Sodium fluorescein in skull base meningiomas: a technical note.

OBJECTIVES: Skull base meningiomas are a neurosurgical challenge due to the involvement of neurovascular structures. In this study, the authors present the first study of the trans-operative use of sodium fluorescein (SF) to enhance skull base meningiomas and perform a quantitative digital analysis of the tumors' pigmentation. The goal of the study was to observe the SF enhancement of skull base meningiomas. PATIENTS AND METHODS: A prospective, within-subjects study was designed and performed. This study included twelve patients with skull base meningiomas. After an initial dissection, digital pictures were taken before and after systematic injections of SF using the same light-source used for the surgical microscope. These pictures were analyzed with software that calculated the wavelengths of the sodium fluorescein before and after the injection of the dye. RESULTS: The meningiomas in the sample included the following types: 1 cavernous sinus, 1 olfactory groove, 3 petroclival, 1 tuberculum sellae, 3 sphenoid wings, 1 anterior clinoid, and 2 temporal floor. The SF enhancement in all tumors was strongly positive. CONCLUSIONS: The low cost, universal availability and safety of SF indicate that this dye should be examined in further studies, and its applications in skull-base meningioma surgeries should be further assessed.

Staged 'intentional' bridging vein ligation: a safe strategy in gaining wide access to skull base tumors.

BACKGROUND: The venous drainage of the temporal lobe, through bridging veins to the middle cranial fossa, is pivotal in determining the surgical corridor for skull base lesions. In dealing with select cases, where venous drainage was an obstacle in the surgical approach, we hypothesized that staged 'intentional' ligation of the dominant pathway of venous drainage would provide a safer and wider access to skull base tumors. We study the indications and safety of this surgical strategy in the management of skull base lesions. MATERIALS AND METHODS: From 1995 to 2012, 318 patients with skull base tumors were treated at our institute by the fronto-orbito-zygomatic (FOZ) or transpetrosal approaches, eight of whom we planned for staged 'intentional' bridging vein ligation. Seven patients underwent planned ligation of the bridging veins from the temporal lobe to the middle cranial fossa floor in the first stage, followed by definitive surgery through the desired skull base approach, in the second stage, while in one patient the strategy was abandoned. These patients were evaluated with respect to their clinical presentation, pre- and post-operative radiology including venogram, intra-operative findings and post-operative course. RESULTS: Seven patients, four males and three females, with ages ranging from 16 to 63 years, underwent staged 'intentional' bridging vein ligation. The diagnoses were recurrent craniopharyngioma in four, and petroclival meningioma, sphenopetroclival meningioma and spheno-orbital meningioma in one each. Six of these lesions were approached from the dominant (left) side, while one lesion was on the right side. Venograms done after the first-stage procedure showed obliteration of the dominant venous drainage with opening up of anastomotic venous channels in all patients. All patients tolerated the first-stage procedure well; only one patient showed asymptomatic mild temporal lobe edema on MRI, which resolved in 3 weeks. None of the patients had venous complications after definitive surgery. One patient with recurrent chordoma, who was planned for staged ligation, did not undergo ligation as, intra-operatively, the draining channel turned out to be a cortical vein, which could be mobilized without ligation. CONCLUSION: In an attempt to detether the temporal lobe, the disconnection of the bridging veins from the temporal lobe to the middle cranial fossa floor in the first stage may lead to re-direction of the venous outflow over time. This may allow skull base surgeons a better surgical corridor and ensure safety of venous structures during the definitive surgery.

Tissue dissection before direct manipulation to the pathology with pulsed laser-induced liquid jet system in skull base surgery--preservation of fine vessels and maintained optic nerve function.

BACKGROUND: Most difficulties in skull base tumor removal are generally caused by adhesion of feeding arteries to the vital structures and cranial nerves. Water jet technology provides tissue dissectability with preservation of fine blood vessels both in experimental and clinical situations. However problems still remain regarding whether tumor removal with preservation of peripheral nerve function is possible or not. This clinical investigation evaluated functional preservation of peripheral nerves and dissectability with a newly developed pulsed laser-induced liquid jet (LILJ) system under intraoperative electrophysiological monitoring. METHODS: The LILJ system was used to treat 21 patients with skull base tumors manifesting as severe visual disturbance through the extended transsphenoidal approach. The LILJ system consists of a bayonet-shaped catheter incorporating a jet generator, and total weight is around 7 g. Intraoperative visual evoked potential (VEP), and pre/postoperative conventional visual assessments were investigated. RESULTS: Precise dissections of the tumor were obtained, resulting in gross total removal in 19 of 21 patients. Two patients with meningiomas with tight adhesion to the origin of the lenticulostriate arteries had small remnants. Of the 21 patients, 16 showed immediate improvement on intraoperative VEP, 2 had no change, and 3 had prolonged latency, which required intermittent suspension of procedure. A total of 20 patients and 40 eyes showed good recovery at discharge, and all patients evaluated had recovered good visual status. CONCLUSIONS: The LILJ system can achieve safe and optimal removal with functional preservation of optic nerves, probably because of the high resistance of the arachnoidal sheath and fine vascular tissue.

[Embolization of skull-base hypervascular tumors: description of a series of cases and proposal of a therapeutic algorithm]. / Embolizacion de tumores hipervasculares de la base del craneo: descripción de una serie de casos y propuesta de un algoritmo terapéutico.

UNLABELLED: Preoperative embolization allows reducing intraoperative blood loss caused by hypervascular intracranial tumors and its undesirable consequences. AIM: To describe the experience with preoperative endovascular embolization of hypervascular skull base tumors, and to develop a therapeutic algorithm. MATERIALS AND METHODS: A retrospective examination of preoperative neuroimaging and results of preoperative embolization was carried out. RESULTS: Fifteen cases were identified, with a median age of 36 years old, most of them harboring meningiomas, nasopharyngeal angiofibromas or paragangliomas. The external carotid artery was involved in 93% of cases and was the only afferent to 60%. In 27%, there were branches from the internal and external carotid arteries simultaneously. An extensive or complete occlusion grade was achieved in 95% of the branches of the external carotid artery. No branch of the internal carotid artery was treated, because poor contribution to tumor irrigation or was not possible to catheterize the pedicle. There were not recorded procedure-related complications. CONCLUSION: Based on the unification of the experiences described in this study and using data from published series, we present an algorithm for rational selection of skull base tumors that can benefit from preoperative embolization.

The role of embolisation in ENT: an update.

OBJECTIVE: To provide an update on the ever-increasing role that embolisation plays in the practice of otolaryngology. METHOD: A literature search was performed during November 2008. The Medline, Embase, PubMed and Cochrane databases were searched. This resulted in 285 papers relevant for review. CONCLUSION: The role of embolisation has expanded greatly to include the management of refractory epistaxis, pre-operative preparation of vascular tumours, vascular injuries and as an adjunct in skull base surgery.

Anomalous origin of the ophthalmic artery from the anterior cerebral artery.

A 39-year-old woman presented with left visual disturbance and diplopia. Magnetic resonance imaging revealed a well-enhanced tumor in the left tentorium, cavernous sinus, and suprasellar region. Angiography demonstrated an abnormal origin of the ophthalmic artery from the anterior cerebral artery. The tumor was partially removed by left frontotemporal craniotomy with orbitozygomatic osteotomy. Intraoperatively, the anomalous origin of the ophthalmic artery was confirmed. This anatomical variation is extremely rare.

Pulsed laser-induced liquid jet for skull base tumor removal with vascular preservation through the transsphenoidal approach: a clinical investigation.

BACKGROUND: The transsphenoidal approach has recently been used to treat complex lesions beyond the sella turcica, but the difficulties of dealing with small vessels, deep and narrow space, and working angle may limit the procedures. To overcome these problems, we have developed a pulsed laser-induced liquid jet (LILJ) system to dissect tumor tissue with preservation of fine blood vessels within deep and narrow working spaces and evaluated its utility and safety. METHODS: The LILJ system was applied to 14 consecutive patients with uncharacteristically complex skull base tumor treated through the extended transsphenoidal approach. This system consists of a bayonet-shaped catheter incorporating a jet generator formed of stainless tube (external diameter 1.10 mm, internal diameter 0.78 mm), which was surrounded by a coaxial polytetrafluoroethylene 14-G equivalent suction tube to be able to incorporate into the confined working spaces. Minor modifications could be fitted for the catheter (15 to 18 cm length, straight or side flexion tip), and total weight was around 7 g. FINDINGS: Precise dissection and mass reduction of the tumor were obtained in all cases except one recurrent case of chordoma with significant fibrosis due to radiation. Both small arteries and veins were preserved, allowing subsequent microsurgical devascularization. Intraoperative blood loss was minimal, and tumor removal rate was satisfactory after the introduction of the system. No complication was related to use of the LILJ system. CONCLUSION: Although comparison between conventional surgical instruments is mandatory in the future, the present study suggests that the LILJ system can achieve safe and optimum removal of complex skull base tumor. Potential application for minimally invasive endoscopic system, as well as potentials for changing the design of the catheter in according to preference of surgeon with low cost, may give advantages over conventional surgical instruments.