Endoscopic transsphenoidal resection of a large chordoma in the posterior fossa

Endoscopic Endonasal Surgical Strategy for Skull Base Chordomas Based on Tumor Growth Directions: Surgical Outcomes of 167 Patients During 3 Years

Background

Skull base chordomas (SBCs) are rare malignant bone tumors with dismal long-term local control. Endoscopic endonasal surgeries (EESs) are increasingly adopted to resect SBCs recently. Gross total resection (GTR) favors good outcomes. However, the SBCs often invade the skull base extensively and hide behind vital neurovascular structures; the tumors were challenging to remove entirely. To improve the GTR, we established a surgical strategy for EES according to the tumor growth directions.

Methods

A total of 112 patients with SBCs from 2018 to 2019 were classified into the derivation group. We retrospectively analyzed their radiologic images and operation videos to find the accurate tumor locations. By doing so, we confirmed the tumor growth directions and established a surgical strategy. Fifty-five patients who were operated on in 2020 were regarded as the validation group, and we performed their operations following the surgical strategy to verify its value.

Results

In the derivation group, 78.6% of SBCs invade the dorsum sellae and posterior clinoid process region. 62.5% and 69.6% of tumors extend to the left and right posterior spaces of cavernous ICA, respectively. 59.8% and 61.6% of tumors extend to the left and right posterior spaces of paraclival and lacerum ICA (pc-la ICA), respectively. 30.4% and 28.6% of tumors extended along the left and right petroclival fissures that extend toward the jugular foramen, respectively. 30.4% of tumors involved the foramen magnum and craniocervical junction region. The GTR was achieved in 60.8% of patients with primary SBCs in the derivation group. Based on the tumors’ growth pattern, pituitary transposition and posterior clinoidectomy techniques were adopted to resect tumors that hid behind cavernous ICA. Paraclival ICA transposition was used when the tumor invaded the posterior spaces of pc-la ICA. Lacerum fibrocartilage resection and eustachian tube transposition may be warranted to resect the tumors that extended to the jugular foramen. GTR was achieved in 75.0% of patients with primary SBCs in the validation group.

Conclusion

Besides the midline clival region, the SBCs frequently grow into the eight spaces mentioned above. The surgical strategy based on the growth pattern contributes to increasing the GTR rate.

A Comparative Study Between Traditional Microscopic Surgeries and Endoscopic Endonasal Surgery for Skull Base Chordomas

BACKGROUND

Skull base chordomas (SBCs) are rare clinically aggressive neoplasms, developing local recurrences after surgical resection. Although SBCs have traditionally been resected by craniotomy or microscopic transsphenoidal surgery (TSS), the recent development of the endoscopic endonasal approach (EEA) has revolutionized treatment strategies through minimally invasive techniques. This study aimed to evaluate clinical outcomes after traditional microsurgeries or EEAs for SBCs.

METHODS

The present retrospective study investigated 66 patients with primary SBCs who underwent surgery between 1977 and 2019. Resection was performed via EEA in 17 cases, craniotomy in 23, transoral approach in 8, TSS in 12, staged surgery in 4, and others in 2. The median follow-up period for progression-free survival (PFS) was 19.5 months.

RESULTS

There were no significant differences in preoperative tumor volume or resection rate among these approaches. The incidence of postoperative cranial nerve palsy was significantly lower in EEA than that in craniotomy (P < 0.05). Although total resection was observed in 4 cases of EEA expanding into the superior and inferior part of the clivus, no cases of transoral approach or TSS achieved total resection for both parts. No significant difference in PFS was found among these approaches. Multivariate analysis showed that being female and the absence of radiotherapy were significantly associated with shorter PFS (P < 0.05 and P < 0.001, respectively). The resection rate was not associated with PFS.

CONCLUSIONS

EEA is a less invasive surgical approach for SBCs. The development of surgical instruments and postoperative radiotherapy will further improve patients' outcomes.

The Endonasal Endoscopic Approach to Pathologies of the Anterior Craniocervical Junction: Analytical Review of Cases Treated at Four European Neurosurgical Centres

Supported by preliminary anatomical and clinical studies exploring the feasibility and usefulness of approaching many ventral pathologies of the craniocervical junction (CCJ) using the endoscopic endonasal approach, four European centres have joined forces to accumulate and share their growing surgical experience of this advanced technique. By describing the steps that led to the development and continuous refinement of this approach to the CCJ, this article delves deeply into an analysis of the cases operated on since 2010 at these four institutions, and discusses in detail the operative nuances that so far have allowed achievement of successful outcomes with excellent perioperative patient comfort and satisfactory long-term quality of life.

The Chopsticks Technique for Endoscopic Endonasal Surgery-Improving Surgical Efficiency and Reducing the Surgical Footprint

BACKGROUND

Variations and additions to the endoscopic endonasal exposure have been proposed around a modular strategy. These extensions are often necessary to provide additional working space and reduce conflict between the instruments and the endoscope. Resection of endonasal structures, which affects negatively the sinonasal quality of life, is thus undertaken not only to obtain tumor exposure but also to improve the maneuverability of the instruments.

OBJECTIVE

Our objective was to achieve the same skull base exposures and tumor resections and limit the surgical footprint on sinonasal structures and patients' quality of life.

METHODS

Our team developed a surgical technique in which the endoscope and a malleable rotative aspirator are held by the nondominant hand and the other main instrument in the dominant hand. This modification, which we call the chopsticks technique, allows the surgeon to use minimalistic exposures with an improved dynamic perception of the surgical field and reduced conflicts between the instruments. The endonasal structures that are left intact help support the instruments. The same surgical objectives, in terms of exposure and resection, are achieved. We describe our technique and a series of patients operated with this uninarial 3-instruments technique to discuss relevant operative nuances.

CONCLUSIONS

We propose a technical modification that allows the surgeons to benefit from the advantages of a bimanual technique while still holding the endoscope. In our opinion, this technique may improve dynamic understanding of the anatomy and surgical efficiency and reduce the footprint of the surgery.

Characterization of the endolysosomal system in human chordoma cell lines: is there a role of lysosomes in chemoresistance of this rare bone tumor?

Chordoma is a rare tumor of the bone derived from remnants of the notochord with pronounced chemoresistance. A common feature of the notochord and chordoma cells is distinct vacuolization. Recently, the notochord vacuole was described as a lysosome-related organelle. Since lysosomes are considered as mediators of drug resistance in cancer, we were interested whether they may also play a role in chemoresistance of chordoma. We characterized the lysosomal compartment in chordoma cell lines by cytochemistry, electron microscopy (ELMI) and mutational analysis of genes essential for the physiology of lysosomes. Furthermore, we tested for the first time the cytotoxicity of chloroquine, which targets lysosomes, on chordoma. Cytochemical stainings clearly demonstrated a huge mass of lysosomes in chordoma cell lines with perinuclear accumulation. Also vacuoles in chordoma cells were positive for the lysosomal marker LAMP1 but showed no acidic pH. Genetic analysis detected no apparent mutation associated with known lysosomal pathologies suggesting that vacuolization and the huge lysosomal mass of chordoma cell lines is rather a relict of the notochord than a result of transformation. ELMI investigation of chordoma cells confirmed the presence of large vacuoles, lysosomes and autophagosomes with heterogeneous ultrastructure embedded in glycogen. Interestingly, chordoma cells seem to mobilize cellular glycogen stores via autophagy. Our first preclinical data suggested no therapeutically benefit of chloroquine for chordoma. Even though, chordoma cells are crammed with lysosomes which are according to their discoverer de Duve "cellular suicide bags". Destabilizing these "suicide bags" might be a promising strategy for the treatment of chordoma.

Transnasal Endoscopic and Lateral Approaches to the Clivus: A Quantitative Anatomic Study

BACKGROUND

Transnasal endoscopic approaches to the clivus have been established recently. Comparative analyses with classic lateral approaches are limited. In this study, we compared transnasal endoscopic and lateral approaches to the clivus, quantifying the exposure and working volume of each approach in the anatomy laboratory.

METHODS

High-resolution computed tomography scans were performed on 5 injected specimens (10 sides). In each specimen, transnasal endoscopic approaches (i.e., paraseptal, transrostral, extended transrostral, transethmoidal, and extended transclival without and with intradural hypophysiopexy) and lateral approaches (i.e., retrosigmoid, far-lateral, presigmoid retrolabyrinthine and translabyrinthine) to the clivus were performed. An optic neuronavigation system and dedicated software (ApproachViewer; Guided Therapeutics Program, University Health Network, Toronto, Ontario, Canada) were used to quantify the working volume and exposed clival area of each approach. Statistical evaluation was performed with the Kruskal-Wallis test and Steel-Dwass-Critchlow-Fligner post hoc test.

RESULTS

Endoscopic transnasal transclival approaches showed higher working volume and larger clival exposure compared with lateral approaches. Incremental volumetric values were evident for transnasal approaches; presigmoid approaches provided less working volume than retrosigmoid approaches. A transnasal transclival approach with hypophysiopexy provided significant exposure of the upper clivus (84.4%). The transrostral approach was the first transnasal approach providing satisfactory access to the midclivus (66%); retrosigmoid and far-lateral approaches provided exposure of approximately one half of the midclivus. The lower clivus was optimally exposed with endoscopic transclival approaches (83%), whereas access to this region was limited with lateral approaches.

CONCLUSIONS

This quantitative anatomic study shows that endoscopic transnasal approaches to the clivus provide a larger working volume and wider exposure of the clivus compared with lateral approaches.

Endonasal Endoscopic Odontoidectomy in Ventral Diseases of the Craniocervical Junction: Results of a Multicenter Experience

BACKGROUND

Over the past decades, supported by preliminary anatomic and clinical studies exploring its feasibility and safety, experience has increased of the use of the endoscopic endonasal approach (EEA) to ventral diseases at the craniocervical junction (CCJ).

METHODS

A multicenter study was carried out over a 4-year period of 14 patients managed by EEA odontoidectomy for CCJ diseases causing irreducible atlantoaxial dislocation. The surgical setup included an IGS system based on computed tomography and magnetic resonance images fusion, and 0° and 30° angled endoscopes with dedicated endoscopic tools.

RESULTS

Nine men and 5 women, with a mean age of 60.7 years, were included. The mean follow-up was 28.5 months; 9 patients had basilar impression, whereas 5 had a degenerative pannus. The quality of anterior decompression was excellent in all cases; nonetheless, a posterior stabilization was deemed necessary in 13 patients, and no external orthosis was used during the postoperative course. No tracheostomy or gastrostomy was required after surgery; no deaths, no new neurologic deficits/complications, and no postoperative cerebrospinal fluid leak were recorded. At follow-up, the neurologic status assessed with Frankel grade did not deteriorate in any of the patients but improved in 13 of them; and no new listhesis was shown on neuroradiologic follow-up.

CONCLUSIONS

The results show that EEA provides a direct surgical corridor to the CCJ, allowing an adequate decompression as with the more invasive transoral route. Morbidity is less than with a transoral approach, resulting in higher patient comfort and faster recovery.

Proton beam therapy in the management of skull base chordomas: systematic review of indications, outcomes, and implications for neurosurgeons

BACKGROUND

Chordomas are rare tumours affecting the skull base. There is currently no clear consensus on the post-surgical radiation treatments that should be used after maximal tumour resection. However, high-dose proton beam therapy is an accepted option for post-operative radiotherapy to maximise local control, and in the UK, National Health Service approval for funding abroad is granted for specific patient criteria.

OBJECTIVES

To review the indications and efficacy of proton beam therapy in the management of skull base chordomas. The primary outcome measure for review was the efficacy of proton beam therapy in the prevention of local occurrence.

METHODS

A systematic review of English and non-English articles using MEDLINE (1946-present) and EMBASE (1974-present) databases was performed. Additional studies were reviewed when referenced in other studies and not available on these databases. Search terms included chordoma or chordomas. The PRISMA guidelines were followed for reporting our findings as a systematic review.

RESULTS

A total of 76 articles met the inclusion and exclusion criteria for this review. Limitations included the lack of documentation of the extent of primary surgery, tumour size, and lack of standardised outcome measures. Level IIb/III evidence suggests proton beam therapy given post operatively for skull base chordomas results in better survival with less damage to surrounding tissue.

CONCLUSIONS

Proton beam therapy is a grade B/C recommended treatment modality for post-operative radiation therapy to skull base chordomas. In comparison to other treatment modalities long-term local control and survival is probably improved with proton beam therapy. Further, studies are required to directly compare proton beam therapy to other treatment modalities in selected patients.

Establishment of clival chordoma cell line MUG-CC1 and lymphoblastoid cells as a model for potential new treatment strategies

Chordomas are rare malignant tumors that develop from embryonic remnants of the notochord and arise only in the midline from the clivus to the sacrum. Surgery followed by radiotherapy is the standard treatment. As chordomas are resistant to standard chemotherapy, further treatment options are urgently needed. We describe the establishment of a clivus chordoma cell line, MUG-CC1. The cell line is characterized according to its morphology, immunohistochemistry, and growth kinetics. During establishment, cell culture supernatants were collected, and the growth factors HGF, SDF-1, FGF2, and PDGF analyzed using xMAP^® technology. A spontaneous lymphoblastoid EBV-positive cell line was also developed and characterized. MUG-CC1 is strongly positive for brachyury, cytokeratin, and S100. The cell line showed gains of the entire chromosomes 7, 8, 12, 13, 16, 18, and 20, and high level gains on chromosomes 1q21–1q24 and 17q21–17q25. During cultivation, there was significant expression of HGF and SDF-1 compared to continuous chordoma cell lines. A new, well-characterized clival chordoma cell line, as well as a non-tumorigenic lymphoblastoid cell line should serve as an in vitro model for the development of potential new treatment strategies for patients suffering from this disease.

Three-dimensional endoscopy in transnasal transsphenoidal approach to clival chordomas

BACKGROUND

The purpose of this prospective, observational study was to evaluate the management of skull base chordomas surgically resected via a 3D-endoscopic transnasal approach.

METHODS

Thirteen consecutive patients were observed and only 9 were surgically treated using a 3D-endoscopic transnasal approach assisted by a novel 3D visualization system.

RESULTS

Nine consecutive male patients (mean age, 57.4 years) underwent exclusive 3D-endoscopic transnasal transsphenoidal resection of clival chordomas; gross total resection was achieved in 66.6% of cases (6 of 9 patients), near-total resection in 11.2% (1 of 9 patients), and partial resection in 22.2% (2 of 9 patients). The complications observed were 2 cases of postoperative cerebrospinal fluid (CSF) leaks and 1 case of temporary VI cranial nerve palsy.

CONCLUSION

No discomfort was recorded; when a dura opening was required, 3D vision allowed an accurate intradural sharp dissection and a precise repair of the skull base. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1814-E1819, 2016.

The endoscopic endonasal approach for extradural and intradural clivus lesions

OBJECTIVE

To report the use of the endoscopic transnasal transclival approach to treat tumors involving the clivus region.

METHODS

The clinical records of 38 patients with clivus lesions were retrospectively reviewed to determine the surgical technique used. All patients were surgically treated using any of the options of the endoscopic transnasal transclival approach at the São Paulo Skull Base Center from 2000-2011. A transsphenoidal, transpterygoidal, retropharyngeal, or a combination of approaches was chosen based on the tumor topography.

RESULTS

Chordomas were the most frequent tumor (26 of 38), followed by chondrosarcoma (2 of 38). Biopsy only was performed in 6 patients with metastasis to the clivus, and 1 patient with fibrous dysplasia underwent a planned partial resection. Gross total resection (GTR) was achieved in 15 of 31 (48%) patients with indications for GTR. For centrally located tumors, GTR was achieved in 75% (15 of 20 patients). Fistula was the most frequent complication (6 of 31; 19%) but was much lower in the most recent series using the nasoseptal flap (1 of 16; 6%). Tumors with lateral extensions or with previous treatment had the worst results. The presence of intradural extension was not a limiting factor for GTR.

CONCLUSION

Endoscopic transnasal surgery is an alternative approach to treatment of clivus lesions, and, in expert hands, this technique can obtain good results. Lateral extension and previous treatment were factors that could make the surgery more difficult. Intradural extension did not limit the radicality of the removal.

Endoscopic endonasal surgery for nonadenomatous sellar/parasellar lesions

INTRODUCTION

This article demonstrates the experience with endoscopic transphenoidal anterior skull base surgery for lesions other than pituitary adenomas. The spectrum of lesions, results, and complications are presented.

PATIENTS AND METHODS

This series includes patients with 102 lesions other than pituitary adenomas operated upon using the endoscopic approach. The results and complications were reviewed retrospectively.

RESULTS

The most common lesions treated were Rathke Cleft Cysts (n = 39) and craniopharyngiomas (n = 18) in a total of 82 tumors. There were 8 patients with inflammatory lesions, and the remainder had a variety of unusual pathologies. Complications other than diabetes insipidus (n = 12) were uncommon, with 6 postoperative cerebrospinal fluid leaks.

CONCLUSIONS

The endoscopic anterior skull base approach is highly effective in treating a large variety of lesions other than pituitary adenomas. The adoption of the nasoseptal flap for closure has markedly reduced the incidence of spinal fluid leaks, and is used routinely for lesions that violate the intracranial compartment.

Surgical approach to pituitary tumors

Pituitary surgery is a continuously evolving specialty of neurosurgery that requires precise anatomical knowledge, technical skills, and an integrated appreciation of pituitary pathophysiology. It involves close cooperation between different specialists, i.e., the endocrinologist, neurosurgeon, neuroradiologist, pathologist, ophthalmologist, and others. It is currently possible to manage many of the different pituitary syndromes with more than one option, including medical, surgical, and radiotherapeutic options, either alone or in various combinations. In recent decades, the transsphenoidal midline route became the standard approach to the pituitary area, this being a less traumatic direct route to the sella, avoiding brain retraction and providing excellent visualization, with a lower morbidity and mortality rate as compared to transcranial procedures. Most pituitary adenomas can be managed and removed through a standard transsphenoidal approach, either microscopic or endoscopic. More recently, the introduction of the endoscope in the extended endoscopic endonasal approach has become more widespread. Here we report current indications and give a step-by-step account of the surgical techniques used in pituitary surgery, focusing on the "dangerous keypoints". We also describe possible complications of each kind of procedure.

Endoscopic endonasal approach in the management of skull base chordomas--clinical experience on a large series, technique, outcome, and pitfalls

Skull base chordomas represent very interesting neoplasms, due to their rarity, biological behavior, and resistance to treatment. Their management is very challenging. Recently, the use of a natural corridor, through the nose and the sphenoid sinus, improved morbidity and mortality allowing also for excellent removal rates. Prospective analysis of 54 patients harboring a skull base chordoma that were managed by extended endonasal endoscopic approach (EEA). Among the 54 patients treated (during a 72 months period), 21 were women and 33 men, undergoing 58 procedures. Twenty-two cases (40%) were recurrent and 32 (60%) newly diagnosed chordomas. Among the 32 newly diagnosed chordomas, a gross total resection was achieved in 28 cases (88%), a near total (>95% of tumor) in 2 cases (6%), a partial (>50% of tumor) in 2 cases (6%). Among the 22 recurrent chordomas, resection was complete in 7 cases (30%), near total in 7 (30%), and partial in 8 (40%). The global gross total resection rate was 65% (35/54 cases). Four patients (11%) recurred and 4 (11%) progressed within a mean follow-up of 34 months (range 12-84 months). Four patients (11%) were re-operated; one patient (1.8%) died due to disease progression, one patient (1.8%) died 2 weeks after surgery due to a massive bleeding from an ICA pseudo aneurysm. CSF leakage occurred in four patients (8%), and meningitis in eight cases (14%). No new permanent neurological deficit occurred. The EEA management of skull base chordomas requires a long and gradual learning curve that once acquired offers the possibility of either similar or better resection rates as compared to traditional approaches while morbidity is improved.

Anatomical restrictions in the transsphenoidal, transclival approach to the upper clival region: a cadaveric, anatomic study

OBJECTIVE

Tumours in the clival region are difficult to remove surgically. Before the 1970s, clival tumours had very high mortality and morbidity rates.

METHODS

An anatomic dissection was performed on 24 spheno-occipital bone blocks obtained from 28 adult cadavers. The internal carotid artery, paraclival carotid tubercle, sixth cranial nerve and dorsum sellae in the upper clival region were analyzed qualitatively and quantitatively. For the histological evaluation, 4 samples were decalcified and sagittal sections were cut. From the eight blocks obtained, 32 incisions were made in the axial plane, and the tissue was analyzed.

RESULTS

Using microscopy, a clival recess was clearly identified in 15 of the 24 (62.5%) samples. Paraclival carotid tubercles were observed in 19 (79.16%) of the samples. In the upper clival and petroclival region, the sixth cranial nerve had directional changes at the dural porus, the petrous apex and the lateral wall of the cavernous segment of the internal carotid artery. At the dorsum sellae level, the distance between the medial surfaces of both internal carotid arteries was a mean of 15.33 ± 2.12 mm. This distance at the pharyngeal tubercle was a mean of 38.95 ± 4.67 mm. On all the histological sections, the distance of the sixth cranial nerve from the dural porus to the cavernous sinus was within the basilar plexus, along with the subarachnoid membranes around it. On the petrous apex level, the sixth cranial nerve was fixed to the petrous apex and the internal carotid artery with connective tissue formed by dense collagen fibres. The sixth cranial nerve and the internal carotid artery are tightly surrounded by dense collagen connective tissue, and the relative proximity between the carotids on the dorsum sellae level can be easily damaged during the transsphenoidal-transclival approach. Similarly, due to the ligamentous fixation on the dural porus and the petrous apex surfaces, there is a high risk of injury to the carotid artery and sixth cranial nerve.

CONCLUSION

This study determines the relationship between the sixth cranial nerve and the internal carotid artery at the upper clivus and to provide morphologic details that is essential for the risks of transclival surgery.

High-resolution computed tomography analysis of the prevalence of Onodi cells

OBJECTIVES/HYPOTHESIS

Onodi cells are the posterior-most ethmoid air cells that lie superior to the sphenoid sinus. Identification of these cells is essential prior to endoscopic sinus and skull base surgery due to their intricate relationship with the optic nerves and carotid arteries, which may lead to deleterious complications. In this study, high-resolution computed tomography (HRCT) scans from 170 adult-patients were analyzed by two independent observers for the presence of Onodi cells.

STUDY DESIGN

Radiographic analysis at a tertiary care medical center.

METHODS

A retrospective analysis was performed on patients undergoing HRCT between July 2008 and September 2010. Incidence of Onodi cells and demographic data were collected.

RESULTS

The overall prevalence of Onodi cells in this cohort was 65.3%. Subgroup analysis based on ethnicity showed a rate of Onodi cells of 83.3% in Asians, 73.1% in whites, 57.0% in African Americans, and 62.7% in Hispanics. The prevalence of Onodi cells was not significantly different among the different ethnicities (P > .05). However, this was limited by a small sample size in some ethnic groups. Onodi cell prevalence was equivalent among males and females: 62.2% and 63.5% respectively (P > .05). Overall, our results show a greater prevalence of Onodi cells than previously reported.

CONCLUSIONS

We found a higher prevalence of Onodi cells in our cohort than previously reported in the literature. Therefore, it is important for surgeons to anticipate the presence of these cells during endoscopic sinus and skull base procedures to prevent potential complications.

A comprehensive analysis of intracranial chordoma and survival: a systematic review

OBJECTIVE

Despite the published information on cranial chordoma, most of the data regarding survival in these patients has come from a single institution. Here, we perform a systematic review of the literature to evaluate across multiple institutions the overall survival after treatment for intracranial chordoma.

MATERIALS AND METHODS

We systematically analysed every study published in English and found a total of over 2000 patients being treated for intracranial chordoma. The overall 5-year and 10-year survivals in these patients were stratified according to the age (<5 years vs. >5 years and  <40 years vs. >40 years), treatment (surgery and radiation vs. surgery alone) and histological findings (chondroid vs. typical). Data were analysed via Pearson chi-square test and student t-test when appropriate.

RESULTS

A total of 560 non-duplicated patients treated for cranial chordoma met inclusion criteria for this systematic analysis. The survival rate among these patients was 63% (299 patients) and 16% (176 patients) for 5-year and 10-year survivals, respectively. There was no difference in overall survival between the two groups when a cut-off age of 40 years was used (<40 years = 50% vs.  >40 years = 51% at 5-year survival; p = 0.1), but when 5 years was used as the cut-off age, then survival was better for patients in the group older than 5 years of age (<5 years = 14% vs.  >5 years = 66%; p = 0.001). There was no difference between 5-year survival in patients with chordoma with histological chondroid features and those with chordoma possessing typical histology (45% vs. 67%; p = 0.06). When patients who only received surgery were compared to those patients who were treated with surgical intervention in combination with adjuvant radiation treatment, no difference in survival rate was found (54% vs. 56% at 5 years; p = 0.8).

CONCLUSION

The results of our systematic study provide data to predict the survival of intracranial chordoma patients across multiple institutions. Our data suggest that patients younger than 5 years of age may be associated with a worse prognosis, and adjuvant radiation therapy and histological type were not associated with the improvement of survival rates.

Clinical significance of MRI-aided measurements in the transsphenoidal approach in Chinese adults

To determine the optimal direction for approaching sellar tumors, we developed an anatomical model of the most common approach, the transsphenoidal approach, in Chinese adults by analyzing MRI-aided measurements. Craniocerebral MRI of 75 Chinese adults with pituitary tumors and 238 healthy Chinese adults were obtained to analyse the angle between the direction of the transsphenoidal approach and the reference line linking the glabella and the external occipital tubercle, the approach depth, and the distance between the internal carotid arteries (ICA) at the cavernous sinuses segment. The mean angle (± standard deviation [SD]) between the direction of the transsphenoidal approach and the reference line in patients with sellar tumors was 40.51 ± 2.98°, similar to the angle in the healthy control group (41.18 ± 3.35°) (p > 0.05). The mean depth (± SD) calculated via the transsphenoidal approach in the sellar tumor group was 86.01 ± 4.99 mm, which was similar to the control group (85.34 ± 4.96 mm) (p > 0.05). However, the mean distance (± SD) between the bilateral ICA at the cavernous sinuses in the patients with sellar tumors was 22.68 ± 5.03 mm, greater than in the control group (15.89 ± 3.11 mm) (p < 0.01). Thus, during sellar tumor resection via the transsphenoidal approach, the patient's head should be first positioned to allow the line linking the glabella and the external occipital tubercle to be perpendicular to the horizontal plane, and then inclined backwards at an angle of about 40°. The floor of the sella, at a depth of about 85 mm, can then be reached vertically by introducing a speculum via a single nostril. The operative field should be limited to about 1cm from the midline. By adopting this method, the optimal angle and depth of the transsphenoidal approach can be determined without complicated equipment. Moreover, this technique is simple and accurate enough to maintain the correct approach, locate the lesion, and reduce the incidence of serious postoperative complications, including bleeding caused by rupture of the ICA.

Technical notes on endoscopic transnasal transsphenoidal approach for clival chondrosarcoma

Although there are various operative approaches for clival tumors, a transsphenoidal approach is one of choices when the main tumor extention is in an anterior-posterior direction with a slight lateral extension. However, this approach sometimes provides only narrow and deep operative field. Recently, endoscopic transnasal transsphenoidal approach is quite an effective approach for clival tumors because of the improvement of surgical instruments, image guidance systems, and techniques and materials of wound closure. In this paper, we describe the effectiveness, technical problems, and solution of this approach based on our experiences with two clival chondrosarcomas that was removed by endoscopic transnasal transsphenoidal approach.

A novel transnasal transsphenoidal speculum: a design for both microscopic and endoscopic transsphenoidal pituitary surgery

Over the last several years minimally invasive surgical approaches to the sella turcica and parasellar regions have undergone significant change. The transsphenoidal approach to this region has evolved from a sublabial transnasal, to transnasal, to pure endonasal approaches with the increasing popularity of endoscopic over microscopic techniques. Endoscopic and microscopic techniques individually or in combination have their own unique advantages, and the preference of one over the other awaits further technological refinements and surgical experience. In parallel with this evolution in techniques for transsphenoidal surgery, the authors designed an adaptable versatile speculum for the endonasal/transnasal transsphenoidal approach to the sella turcica and parasellar regions that can be used equally effectively with a microscope or an endoscope. The development of this instrument and its unique features are described, and its initial clinical use is summarized. This transnasal transsphenoidal speculum has interchangeable blades, unique blade angulations, and independent blade opening mechanisms and allows safe, optimal exposure in all patients regardless of the size and anatomical aberrations of individual nasal and endonasal regions. An attached endoscope carrier further allows it to be used interchangeably with microscopic or endoscopic techniques without having to remove the speculum; likewise, a single surgeon can use both hands without need of an assistant. A forehead headrest component adds further stabilization. This device has been used successfully in 90 transsphenoidal procedures.

Clival chordomas: clinical management, results, and complications in 71 patients

Object

Chordomas are rare malignant neoplasms arising predominantly at the sacrum and skull base. They are uniformly lethal unless treated with aggressive resection and proton beam irradiation. The authors present results of the surgical management of a large number of patients with clivus chordomas. Factors that influence the surgeon's ability to achieve radical tumor resection are also evaluated.

Methods

Between 1991 and 2005, 71 patients with clivus chordomas underwent surgery. The average follow-up was 66 months (median 60 months, range 3–189 months). Sixty-five patients had complete records that were analyzed in the present report. Thirty-five percent of them had undergone surgery before being treated by the authors. They were evaluated with MR imaging and CT scanning and underwent surgery utilizing a variety of skull base techniques aimed at achieving radical excision. Many also underwent postoperative radiation, usually in the form of proton beam therapy. The patients were followed up with serial imaging at regular intervals as well as with neurological evaluation.

Results

Radical tumor resection was achieved in 58% of the group. The overall 5-year survival rate was 75%. Radical resection had a positive impact on survival. The ability to achieve radical resection was dependent on the preoperative tumor volume and the number of anatomical areas involved by the tumor. Cranial nerve impairment and CSF leakage were the most frequent postoperative complications.

Conclusions

Radical excision is the ideal surgical goal in the treatment of clival chordomas and can be achieved with reasonable risks. Several different surgical approaches may be necessary to accomplish this.

Endoscopic management of sphenoclival neoplasms: anatomical correlates and patient outcomes

OBJECTIVE

To characterize the endoscopic anatomy of the sphenoid sinus and the adjacent clivus and cavernous sinus, and to review patient outcomes for neoplasms in this region.

STUDY DESIGN

Cadaver dissection and chart review.

SETTING

Cadaver laboratory and tertiary care center.

SUBJECTS AND METHODS

Fresh-frozen cadaver heads were dissected to study the endoscopic anatomy of the sphenoclival region. Retrospective chart review of patients undergoing endoscopic resection of sphenoclival neoplasms between 2000 and 2008 was performed.

RESULTS

Transnasal endoscopic access to the sphenoid sinus was obtained in 10 cadaver heads. A clival window with mean dimensions of 1.4 cm x 1.7 cm was created. Through the clival window, identification and dissection of the basilar and vertebral arteries, mamillary bodies, third ventricle, cranial nerves III through VI, and cervical rootlets were possible. Nineteen patients with mean age of 56.2 years were treated. The most common pathologies were inverted papilloma (5), chordoma (4), squamous cell carcinoma (2), and adenoid cystic carcinoma (2). None of the patients required adjunct craniotomies. Nine patients received adjuvant therapies. Thirteen (68.4%) patients had no evidence of disease, five (26.3%) patients were alive with disease, and one (5.3%) patient died of disease at mean follow-up of 32.6 months.

CONCLUSION

The sphenoclival region poses a significant surgical challenge given its central location at the skull base and proximity to critical structures. This study demonstrates that transnasal endoscopic access to the sphenoclival region is technically feasible and allows successful surgical extirpation of tumors with a low complication rate and acceptable patient outcomes.

Endoscopic endonasal transclival approach and retrosigmoid approach to the clival and petroclival regions

OBJECTIVE

The removal of clival lesions, mainly those located intradurally and with a limited lateral extension, may be challenging because of the lack of a surgical corridor that would allow exposure of the entire lesion surface. In this anatomic study, we explored the clival/petroclival area and the cerebellopontine angle via both the endonasal and retrosigmoid endoscopic routes, aiming to describe the respective degree of exposure and visual limitations.

METHODS

Twelve fresh cadaver heads were positioned to simulate a semisitting position, thus enabling the use of both endonasal and retrosigmoid routes, which were explored using a 4-mm rigid endoscope as the sole visualizing tool.

RESULTS

The comparison of the 2 endoscopic surgical views (endonasal and retrosigmoid) allowed us to define 3 subregions over the clival area (cranial, middle, and caudal levels) when explored via the endonasal route. The definition of these subregions was based on the identification of some anatomic landmarks (the internal carotid artery from the lacerum to the intradural segment, the abducens nerve, and the hypoglossal canal) that limit the bone opening via the endonasal route and the natural well-established corridors via the retrosigmoid route.

CONCLUSION

Different endoscopic surgical corridors can be delineated with the endonasal transclival and retrosigmoid approaches to the clival/petroclival area. Some relevant neurovascular structures may limit the extension of the approach and the view via both routes. The combination of the 2 approaches may improve the visualization in this challenging area.

Endoscopic Approach to the Infratemporal Fossa

OBJECTIVE

Classic surgical exposures of the infratemporal fossa region, including the adjacent intracranial space, temporal bone, and sinonasal region, require the extensive exposure associated with the transcranial, transfacial, and transmandibular approaches with their inherent neurological and cosmetic morbidities. In this study, we evaluated the feasibility and exposure afforded by combining 2 endoscopic transmaxillary approaches, endonasal and Caldwell-Luc supplement, to the infratemporal fossa.

METHODS

Endoscopic transmaxillary dissection was performed in 4 formalin-fixed cadaver heads (8 sides). We quantified the extent of exposure achieved within the pterygopalatine and infratemporal fossae after our initial dissection, which was endonasal with a medial antrostomy, and after addition of a Caldwell-Luc incision with an anterior antrostomy. Complementing this anatomic study, we report on a patient in whom this endoscopic transmaxillary approach combining the endonasal and Caldwell-Luc approaches was used for resection of a trigeminal schwannoma in the infratemporal fossa.

RESULTS

The combination of these 2 endoscopic transmaxillary approaches enabled visualization of the entire region of the pterygopalatine fossa and anteromedial aspect of the infratemporal fossa. Additional posterolateral exposure of the infratemporal fossa requires significant traumatic traction on the nose. Addition of the Caldwell-Luc transmaxillary approach exposed the remainder of the infratemporal fossa, including the mandibular nerve and branches, middle meningeal artery, and even the distal cervical portion of the internal carotid artery.

CONCLUSION

Endoscopic exposure of the infratemporal fossa is feasible. Using the combination of the endonasal and Caldwell-Luc approaches for direct transmaxillary access significantly extended exposure, allowing safe and effective resection of infratemporal fossa lesions.

Surgical treatment of a clival-C2 atypical teratoid/rhabdoid tumor

The authors present the case of en bloc resection of a clival-C2 atypical teratoid/rhabdoid tumor. These aggressive lesions of early childhood generally occur in the cerebellum or cerebral hemispheres. This 7-year-old boy presented with pain on turning his head and was found to have a clival-C2 mass. A metastatic workup was negative for disseminated disease. A transoral biopsy procedure revealed an atypical teratoid/rhabdoid tumor on histological examination. The tumor was resected via a transoral approach, and the patient's spine was stabilized with posterior instrumented fusion from the occiput to C-5. Postoperatively, the patient underwent 16 months of chemotherapy along with 6 weeks of overlapping radiation therapy. Twenty-seven months after the initial surgery he presented with leg pain and was found to have a solitary metastatic lesion at the conus medullaris. There was no local recurrence at the clivus. The conus tumor was resected and found to be consistent with the primary tumor. Several months later the patient presented with disseminated intrathecal disease and ultimately died 42 months after the initial resection.

Adjuvant radiation therapy and chondroid chordoma subtype are associated with a lower tumor recurrence rate of cranial chordoma

Cranial chordomas are rare tumors that have been difficult to study given their low prevalence. Individual case series with decades of data collection provide some insight into the pathobiology of this tumor and its responses to treatment. This meta-analysis is an attempt to aggregate the sum experiences and present a comprehensive review of their findings. We performed a comprehensive review of studies published in English language literature and found a total of over 2,000 patients treated for cranial chordoma. Patient information was then extracted from each paper and aggregated into a comprehensive database. The tumor recurrences in these patients were then stratified according to age (<21 vs. >21 years), histological findings (chondroid vs. typical) and treatment (surgery and radiation vs. surgery only). Data was analyzed via Pearson chi-square and t-test. A total of 464 non-duplicated patients from 121 articles treated for cranial chordoma met the inclusion criteria. The recurrence rate among all patients was 68% (314 patients) with an average disease-free interval of 45 months (median, 23 months). The mean follow-up time was 39 months (median, 27 months). The patients in younger group, patients with chordoma with chondroid histologic type, and patients who received surgery and adjuvant radiotherapy had significantly lower recurrence rate than their respective counterparts. The results of our systematic analysis provide useful data for practitioners in objectively summarizing the tumor recurrence in patients with cranial chordomas. Our data suggests that younger patients with chondroid type cranial chordoma treated with both surgery and radiation may have improved rates of tumor recurrence in the treatment of these tumors.

ENDOSCOPIC ENDONASAL APPROACH FOR CLIVAL CHORDOMAS

OBJECTIVE

Cranial base chordomas are difficult lesions to treat. The endoscopic endonasal approach (EEA) takes advantage of the natural sinus corridor and may provide a less invasive approach for these midline tumors.

METHODS

Patients undergoing EEA for chordomas were selected from a database of more than 800 consecutive patients undergoing EEA at the University of Pittsburgh Medical Center and were retrospectively evaluated. Additionally, a systematic review of the literature of endoscopic endonasally resected chordomas was performed and compared with our personal experience.

RESULTS

Twenty patients (8 females and 12 males) underwent 26 endoscopic EEAs for cranial base chordomas. Eight chordomas (40%) were recurrent. Treatment of the 12 newly diagnosed chordomas included 8 total resections (66.7%), 2 near total resections (16.7%), and 2 subtotal resections (16.7%). Treatment of the 8 recurrent chordomas included 1 gross total resection (12.5%), 2 near total resections (25.0%), and 5 subtotal resections (62.5%). Two patients (10%) had recurrences, and 5 patients (25%) progressed during the mean follow-up period of 13 months (range, 1–45 months). Five patients (25%) underwent re-resection, 1 patient was lost to follow-up, and 1 patient died secondary to progression of disease. There was 1 intraoperative vascular complication with no sequelae. The cerebrospinal fluid leak rate was 25%, and there were no cases of bacterial meningitis. The incidence of a new permanent neurological complication was 5%. A systematic review of the literature yielded a total of 26 cases of chordomas resected via a completely endoscopic endonasal technique.

CONCLUSION

Endoscopic endonasal resection of cranial base chordomas is safe once adequate experience is gained with the technique. This approach provides the potential for, at the least, similar resections compared with traditional cranial base approaches while potentially limiting morbidity.

Endoscopic skull base surgery

Endoscopic skull base surgery has undergone rapid advancement in the past decade moving from pituitary surgery to suprasellar lesions and now to a myriad of lesions extending from the cribriform plate to C2 and laterally out to the infratemporal fossa and petrous apex. Evolution of several technological advances as well as advances in understanding of endoscopic anatomy and the development of surgical techniques both in resection and reconstruction have fostered this capability. Management of benign disease via endoscopic methods is largely accepted now but more data is needed before the controversy on the role of endoscopic management of malignant disease is decided. Continued advances in surgical technique, navigation systems, endoscopic imaging technology, and robotics assure continued brisk evolution in this expanding field.

JUVENILE INTRADURAL CHORDOMA

OBJECTIVE

We report the youngest known case of a prepontine intradural chordoma. These tumors are exceedingly rare. Unlike their more common extradural counterparts, no recurrence of an intradural chordoma has been reported.

CLINICAL PRESENTATION

A 9-year-old boy underwent diagnostic imaging for evaluation of headaches. Although neurologically intact, a magnetic resonance imaging scan revealed a large prepontine mass with focal enhancement.

INTERVENTION

Endoscopic-assisted gross total resection was attained with staged bilateral retrosigmoid approaches. There were no additional adjuvant therapies. At the time of the 1-year follow-up evaluation, the patient had no recurrence.

CONCLUSION

By using an endoscopic-assisted procedure, we achieved complete resection of an intradural chordoma offering a potential for surgical cure. Resection is particularly advantageous because it spares the young child the need for radiation treatment. Close follow-up is warranted because we postulate that this tumor exists in a biological continuum between benign notochordal hamartomatous remnants and typical invasive chordomas.

Tumor-biology and current treatment of skull-base chordomas

Chordomas are rare, slow growing tumors of the axial skeleton, which derive from the remnants of the fetal notochord. They can be encountered anywhere along the axial skeleton, most commonly in the sacral area, skull base and less commonly in the spine. Chordomas have a benign histopathology but exhibit malignant clinical behavior with invasive, destructive and metastatic potential. Genetic and molecular pathology studies on oncogenesis of chordomas are very limited and there is little known on mechanisms governing the disease. Chordomas most commonly present with headaches and diplopia and can be readily diagnosed by current neuroradiological methods. There are 3 pathological subtypes of chordomas: classic, chondroid and dedifferentiated chordomas. Differential diagnosis from chondrosarcomas by radiology or pathology may at times be difficult. Skull base chordomas are very challenging to treat. Clinically there are at least two subsets of chordoma patients with distinct behaviors: some with a benign course and another group with an aggressive and rapidly progressive disease. There is no standard treatment for chordomas. Surgical resection and high dose radiation treatment are the mainstays of current treatment. Nevertheless, a significant percentage of skull base chordomas recur despite treatment. The outcome is dictated primarily by the intrinsic biology of the tumor and treatment seems only to have a secondary impact. To date we only have a limited understanding this biology; however better understanding is likely to improve treatment outcome. Hereby we present a review of the current knowledge and experience on the tumor biology, diagnosis and treatment of chordomas.

Radiosurgery for chordomas and chondrosarcomas of the skull base

OBJECT

Chordomas and chondrosarcomas of the skull base are aggressive and locally destructive tumors with a high tendency for local progression despite treatment. The authors evaluated the effect of stereotactic radiosurgery (SRS) on local tumor control and survival.

METHODS

Twenty-eight patients with histologically confirmed chordomas (18) or chondrosarcomas (10) underwent Gamma Knife SRS either as primary or adjuvant treatment. Their ages ranged from 17 to 72 years (median 44 years). The most common presenting symptom was diplopia (26 patients, 93%). In two patients, SRS was the sole treatment. Twenty-six patients underwent between one and five additional surgical procedures. Two underwent an initial transsphenoidal biopsy. The average tumor volume was 9.8 cm3. The median dose to the tumor margin was 16 Gy.

RESULTS

No patient was lost to follow-up. Transient symptomatic adverse radiation effects developed in only one patient. The actuarial local tumor control for chondrosarcomas at 5 years was 80 +/- 10.1%. For chordomas both the actuarial tumor control and survival was 62.9 +/- 10.4%.

CONCLUSIONS

Stereotactic radiosurgery is an important option for skull base chordomas and chondrosarcomas either as primary or adjunctive treatment. Multimodal management appears crucial to improve tumor control in most patients.

Fully endoscopic expanded endonasal approach treating skull base lesions in pediatric patients

OBJECT

The authors reviewed their experience with endoscopic approaches to determine their safety and efficacy in the treatment of pediatric patients who harbor skull base lesions. Although they were interested in ascertaining outcomes after surgery as well as validating and defining indications and limitations of these approaches, the authors recognized that the follow-up duration was inadequate to assess long-term outcomes.

METHODS

The authors conducted a retrospective review of all endoscopic procedures performed at their institution between January 2000 and September 2005. The procedures were categorized into a series of anatomical modular approaches. Twenty-five patients 18 years of age or younger were identified. The surgical goals were individualized and included gross-total resection, partial resection, biopsy, decompression of neural structures, and repair of a cerebrospinal fluid (CSF) leak. One patient required an open procedure in addition to the expanded endonasal approach for definitive therapy. No patient suffered a neurological deficit, vascular injury, or central nervous system infection. A CSF leak was the most common complication and occurred in two (8%) of the 25 patients.

CONCLUSIONS

In well-selected patients, the expanded endonasal approach represents a safe, effective, and minimally invasive technique for the treatment of skull base lesions in children. Incremental experience is needed for acquiring the skills with endoscopic techniques to progress to the more complex modular approaches.

Resection of extensive sellar tumors with extended endoscopic transseptal transsphenoidal approach

The endoscope has recently been used to extensive sellar lesions, but the extended areas of the lesions and operative techniques vary from each study. Here we present our experience with extended endoscopic transseptal transsphenoidal (EETT) approach to 16 patients with extensive sellar lesion and evaluate the feasibility of EETT in different extensive sellar tumor resection. Sixteen patients with extensive sellar lesion were operated by EETT approach in this study. The approach included unilateral posterior septum mucosa resection, posterior septectomy, extended ethmoidectomy and sphenoidoctomy, four tumoral circumferences (bilateral, superior, inferior aspects) isolated and subsequently tumoral removal from outside to inside of the tumors obtained. This surgical procedure is satisfactory for sellar lesion with different juxtasellar extension. After surgery, CT scan and MR image showed that total removal of the tumor was achieved in 10 patients. Six patients who received subtotal resection were treated with postoperative radiation therapy or gamma knife surgery. Two patients developed postoperative cerebrospinal fluid leak that was successfully managed by conservative treatment within 6 days after surgery. No other new postoperative endocrinological or neurological defects occurred. Six months to 5 years follow up indicated that all 16 patients with the visual disturbances and 4 patients with endocrine impairments have recovered or improved. One patient with malignant meningioma died due to recurrence of the tumor 2 years postoperation. Another one patient with malignant inverted papilloma recurred 1 year postoperation and underwent operation and radiation therapy again. The EETT approach might better facilitate the removal of different extensive sellar lesions with maximal preservation of important anatomical structures and nasal function.

The extended endoscopic endonasal approach to the clivus and cranio-vertebral junction: anatomical study

OBJECT

Lesions located in the retroclival area and at the level of the cranio-vertebral junction are typically approached through a variety of anterior, antero-lateral and postero-lateral skull-based approach, either alone or in combination. The aim of this anatomical study was to demonstrate the possibility of an endoscopic endonasal approach to the clivus and cranio-vertebral junction.

MATERIALS AND METHODS

Five fresh cadaver heads injected with colored latex were used. A modified endonasal endoscopic approach was made through two nostrils in all cases. Endoscopic dissections were performed using rigid endoscopes, 4 mm in diameter, 18 cm in length, with 0 degrees lenses.

RESULTS

Access to the clivus was possible using a lower trajectory when compared to that necessary for the sellar region. The sphenoid sinus is entered, and its inferior wall is completely removed, permitting the union of the sphenoidal and rhinopharyngeal parts of the clivus. The entire clivus can be removed, and the cranio-vertebral junction is opened, removing the anterior arch of atlas and the odontoid process. After the opening of the dura, the anterior surface of the pons and upper spinal cord with corresponding nerves and vasculature are visible.

CONCLUSION

The endoscopic endonasal approach to the clivus and cranio-vertebral junction could be a valid alternative for surgical treatment of anterior lesions of these regions. Adequate endoscopic skill, lab training on cadavers and dedicated tools are required for clinical applications of the approach.

Pure endoscopic endonasal odontoidectomy: anatomical study

Different disorders may produce irreducible atlanto-axial dislocation with compression of the ventral spinal cord. Among the surgical approaches available for a such condition, the transoral resection of the odontoid process is the most often used. The aim of this anatomical study is to demonstrate the possibility of an anterior cervico-medullary decompression through an endoscopic endonasal approach. Three fresh cadaver heads were used. A modified endonasal endoscopic approach was made in all cases. Endoscopic dissections were performed using a rigid endoscope, 4 mm in diameter, 18 cm in length, with 0 degree lenses. Access to the cranio-vertebral junction was possible using a lower trajectory, when compared to that necessary for the sellar region. The choana is entered and the mucosa of the rhinopharynx is dissected and transposed in the oral cavity in order to expose the cranio-vertebral junction and to obtain a mucosal flap useful for the closure. The anterior arch of the atlas and the odontoid process of C2 are removed, thus exposing the dura mater. The endoscopic endonasal approach could be a valid alternative to the transoral approach for anterior odontoidectomy.

Expanded endonasal approach: a fully endoscopic completely transnasal resection of a skull base arteriovenous malformation

OBJECTIVE AND IMPORTANCE

Vascular lesions with an intraosseus nidus involving the skull base are uncommon and challenging [Gianoli GJ, Amedee RG Vascular malformation of the sphenoid sinus. Ear Nose Throat J. 70:373-375;(1991), Malik GM, Mahmood A, Mehta BA Dural arteriovenous malformation of the skull base with intraosseous vascular nidus. Report of two cases. J. Neurosurg 81:620-623;(1994)]. We present a pediatric patient, with a life-threatening arteriovenous malformation (AVM) of the sphenoid sinus, clivus, and ventral skull base, who failed routine multimodality management of AVMs. An entirely transsphenoidal fully endoscopic resection was used to resect this ventral cranial base AVM with an intraosseus nidus located in the clivus.

CLINICAL PRESENTATION

A 4-year-old female presented with recurrent, life-threatening hemorrhages from a clival and ventral skull base AVM of the entire clivus and ventral skull base. The patient had been temporized from the age of 2-4 years with multiple internal and external carotid arterial particulate and alcohol embolizations, including both external and internal carotid artery embolizations, intracranial ligation of the right internal carotid artery, and gamma knife irradiation. Despite these multiple interventions, the patient had persistent, life-threatening hemorrhages from arterial recanalization and recruitment requiring intubation, tracheostomy, and nasopharyngeal packing.

INTERVENTION

The patient underwent a three-stage surgical intervention to resect the AVM. An open subfrontal approach, as the first procedure, provided minimal access to the feeding vessels and was therefore aborted. A two-stage image-guided fully endoscopic approach via a sublabial midface approach without external incisions was performed. Postoperative angiography revealed minimal residual shunting in the pharynx and cavernous sinus. The patient has been free of significant hemorrhages over the past three years.

CONCLUSION

Technological advances in endoscopic surgery and image guidance are now allowing for purely endoscopic surgical treatment of previously unresectable lesions with acceptable morbidity. We report the successful and safe resection of a ventral cranial base AVM via a fully endoscopic approach. This paper reports the first AVM with a purely intraosseus nidus of the ventral skull base and demonstrates the ability to deal with complex ventral skull base lesions using a fully endoscopic transsphenoidal technique.

Petrous apex cholesterol granuloma treated via the endoscopic transsphenoidal approach

Numerous surgical approaches have been used to treat petrous apex cholesterol granulomas. They are usually treated via the transtemporal- or middle fossa approach; some are managed endoscopically. We present a patient treated by the endoscopic transsphenoidal approach and review the literature.

Anatomical study of the pterygopalatine fossa using an endoscopic endonasal approach: spatial relations and distances between surgical landmarks

OBJECT

The pterygopalatine fossa is an area that lies deep within the skull base. The recent extensive use of the endoscopic endonasal approach has provided neurosurgeons with a method to reach various areas of the skull base through a less invasive approach than traditional transcranial or transfacial approaches. This study aims to provide neurosurgeons with new data concerning direct endoscopic measurements and precise anatomical topography features of the pterygopalatine fossa.

METHODS

An anatomical dissection of six fixed cadaver heads (12 pterygopalatine fossae) was performed to analyze spatial relationships and distances between the most important neurovascular structures in this region, and to estimate the size of the endoscopic surgical field for operations in this area. The endoscopic endonasal approach offers direct access to the pterygopalatine fossa through its anteromedial walls.

CONCLUSIONS

Using an endoscopic endonasal approach makes it possible to identify all of the anatomical landmarks of the pterygopalatine fossa and almost all of the contiguous skull base areas.

The endoscopic transnasal transsphenoidal approach for the treatment of cranial base chordomas and chondrosarcomas

OBJECTIVE

We report our experience with endoscopic transsphenoidal or extended endoscopic transsphenoidal approaches for the treatment of cranial base lesions such as clival chordomas and chondrosarcomas.

METHODS

Between May 1998 and April 2004, 11 patients (four were recurrences because they previously had been treated with surgery and/or radiotherapy) underwent transnasal transsphenoidal endoscopic surgery for cranial base chordomas and chondrosarcomas at the Neurosurgical Department of Bellaria Hospital in Bologna. The transsphenoidal endoscopic approach and the ethmoid-pterygo-sphenoidal endoscopic approach were used to accomplish resection of the lesions involving the clivus and extending up to the parasellar region and to the petrous apex, or within the cavernous sinus.

RESULTS

Patient follow-up periods ranged from 15 to 69 months (mean, 27 mo). Three patients died of chordoma progression at 20, 14, and 10 months, respectively, after endoscopic treatment. One patient experienced two recurrences; the first was treated using a new endoscopic approach, whereas the second, 1 year later, was treated by means of a far lateral approach. Four patients underwent postoperative proton beam radiotherapy, whereas one underwent a conventional megavoltage x-radiation therapy. However, postoperative radiotherapy was not administered in the two patients treated for cranial base chondrosarcoma.

CONCLUSION

The flexibility of this new technique with respect to the classical microscopic transsphenoidal approach permits us to widen the horizon of surgical management of aggressive cranial base tumors such as clival chordomas and chondrosarcomas.

Back to the Egyptians: neurosurgery via the nose. A five-thousand year history and the recent contribution of the endoscope

The possibility of removing the brain through the nose without disfiguring the face was already known to the ancient Egyptians, who were experts in using this approach in the mummification process. A similar route through the nose and the sphenoid bone has been developed in the last century as a surgical procedure for the treatment of tumors of the pituitary region, which makes the more invasive craniotomy unnecessary in most cases. This has resulted in a significant decrease of the overall mortality and morbidity rates and has led to the great popularity of such minimally invasive surgery both for patients and doctors. The recent advent of the endoscope in this specific field and the development of further possibilities and instrumentation has contributed to a new renaissance of this old treatment modality.

Basilar expansion of the human sphenoidal sinus: an integrated anatomical and computerized tomography study

Basilar expansion of the sphenoidal sinus (BESS) was studied in order to demonstrate its critical relevance in endoscopic or microscopic endonasal surgical interventions, including access to the sphenoidal sinus itself or in transsphenoidal pituitary approaches. Direct evaluation of anatomical specimens (25 dry skulls and 25 formalin-fixed hemi heads) and the use of computerized tomography (CT) (50 dry skulls and 750 patients) showed a high BESS frequency (69%). The authors considered BESS to be critical when the posterior wall of the clivus was 2-mm thick and found a high incidence of this important anatomical variation (44%). This study also evaluated the relationship between the sinonasal septa, the clivus, and the internal carotid arteries, and a considerable regularity in the location of these structures was seen. The septa were anatomically related to the internal carotid arteries in 55% and to the clivus in 33% of the cases. In conclusion, the high frequency of critical BESS here described is relevant to endoscopic or microscopic endonasal surgical interventions, including access to the sphenoidal sinus itself or in transsphenoidal pituitary approaches.

Transnasal endoscopic resection of lesions of the clivus: a preliminary report

OBJECTIVE

To review our experience with transnasal endoscopic resection of clival lesions.

BACKGROUND

Because of the surrounding vital structures and the difficulties in achieving wide surgical exposure, the treatment of clival lesions is challenging. In an effort to overcome these obstacles, many centers use facial incisions and osteotomies to approach clival lesions. Minimally invasive endoscopic techniques have the potential to minimize morbidity while yielding similar surgical results.

STUDY DESIGN

Retrospective chart analysis.

MATERIALS AND METHODS

Patients with tumors involving the clivus that underwent endoscopic resection between 2000 and 2004 were identified. Charts were reviewed for clinical characteristics, previous therapies, diagnosis, tumor extent, management modalities, length of hospital stay, complications, and outcome.

RESULTS

A total of six patients were identified. There were four males and two females with a mean age of 50 years, ranging from 29 to 66 years. The most common presenting symptoms were visual disturbances. Three patients had prior craniotomy with subtotal tumor resection. The pathology included three clival chordomas, and one each of meningioma, adenoid cystic carcinoma, and sinonasal undifferentiated carcinoma. All patients were managed with computer-aided transnasal endoscopic tumor resection with neurosurgical standby or involvement. None of the patients required additional craniotomies. The mean follow-up was 13 (range, 8-24) months. Intensity-modulated radiation therapy was used in three patients, and two patients are currently undergoing proton beam radiation therapy (PBRT). The average length of hospital stay was 2 (range, 2-3) days. There were no major postoperative complications. At the last follow-up, five patients were alive with two patients being free of disease. Two patients with residual disease are currently undergoing PBRT, and one patient developed distant metastasis. One patient died of unrelated causes.

CONCLUSIONS

This preliminary report suggests that transnasal endoscopic management of clival lesions is a viable option to traditional open approaches with acceptable morbidity and mortality. The use of computer-aided surgery further minimizes surgical risks while maximizing tumor resection.

Skull base surgery: past, present, and future trends

The author outlines the history of skull base surgery and describes the new paradigm emerging with increasing use of endoscopic microneurosurgery.

Extended endoscopic endonasal approach to the pterygopalatine fossa: anatomical study and clinical considerations

Object

The pterygopalatine fossa is an area located deep in the skull base. The microsurgical transmaxillary–transantral route is usually chosen to remove lesions in this region. The increasing use of the endoscope in sinonasal functional surgery has more recently led to the advent of the endoscope for the treatment of tumors located in the pterygopalatine fossa as well.

Methods

An anatomical dissection of three fresh cadaveric heads (six pterygopalatine fossas) and three dried skull base specimens was performed to evaluate the feasibility of the approach and to illustrate the surgical landmarks that are useful for operations in this complex region.

The endoscopic endonasal approach allows a wide exposure of the pterygopalatine fossa. Furthermore, with the same access (that is, through the nostril) it is possible to expose regions contiguous with the pterygopalatine fossa, either to visualize more surgical landmarks or to accomplish a better lesion removal.

Conclusions

In this anatomical study the endoscopic endonasal approach to the pterygopalatine fossa has been found to be a safe approach for the removal of lesions in this region. The approach could be proposed as an alternative to the standard microsurgical transmaxillary–transantral route.

Endoscopy and Transsphenoidal Surgery

ENDOSCOPY OFFERS INTERNAL visualization of many different cavities of the human body, with its specific vision inside the anatomy, close to the target area. The view of the surgical field in transsphenoidal surgery had been obtained with the naked eye from its beginning in 1907 up to the introduction of the operating microscope by Jules Hardy in the 1960s, which represented a great advance in terms of magnification and illumination. In the past decade, modern rigid endoscopes, with their wider view near the relevant anatomy, have permitted minimally traumatic transsphenoidal procedures in and around the sellar area, thus representing a "new wave" in transsphenoidal history. An overview of the evolution of the endoscope as a visualizing and operating instrument particularly related to the transsphenoidal approach is presented here. The current possibilities of transsphenoidal endoscopy, with its related advantages and limitations, are presented.