[Expanded Endoscopic Endonasal Surgery for Skull Base Tumors].

With the development of endoscopic and surgical instruments, expanded endoscopic endonasal surgery for skull base tumors has been widely performed. Compared with conventional microscopic transsphenoidal surgery, endoscopic surgery provides a wider view and clearer images, owing to the introduction of a high-resolution camera. However, for safe and reliable surgery, it is necessary to create an appropriate surgical field and avoid complications. This article discusses the basic knowledge needed for expanded endoscopic endonasal surgery, focusing on surgical anatomy and techniques and how to close the skull base completely.

Optimal Multiple-Layered Anterior Skull Base Reconstruction Using a 360° Suturing Technique.

BACKGROUND: Advances in technique and instrumentation have improved outcomes after resection of anterior skull base tumors. However, cerebrospinal fluid (CSF) leak occurs in 4%-20% of patients. To reduce the risk of CSF leak, we have developed a novel reconstruction technique that consists of a 4-layered graft with patchwork suturing and hard material. OBJECTIVE: To evaluate the effectiveness of this reconstruction technique when used for resection of anterior skull base tumors. METHODS: This case series included 59 patients with anterior skull base tumors in whom the 4-layered closure technique was used. The main outcome measures were complications, including CSF leak, meningitis, postoperative bleeding, and infection. RESULTS: There were no CSF leak cases or serious complications after closure of the anterior skull base using the 4-layered technique. CONCLUSION: Closure of the anterior skull base in 4 layers prevented CSF leak and was not associated with any serious complications. However, further studies in larger numbers of patients are needed to confirm our outcomes using this closure method.

Advanced Endoscopic Endonasal Approach to the Pterygopalatine Fossa and Orbit: The Endoscopic Tri-port Approach.

Objective The pterygopalatine fossa (PPF) is a narrow space situated posterior to the maxillary sinus. While external approaches have been used to treat tumors of the PPF, recent endoscopic approaches have become favored as an alternative; we developed an endoscopic tri-port approach, which provides wide surgical corridor with minimal invasion, for PPF. This report aims to introduce and verify the new approach. Design Case series. Setting A tertiary referral hospital. Participants We reviewed 11 patients with PPF or orbital tumors who were treated with the endoscopic tri-port approach. Main Outcome Measures Accessing tri-port approach's effects and limitations. Results When the tumor was located in the PPF or orbit without intracranial invasion, en bloc resection was achieved in six patients. With the exception of one patient, the nasal septum was preserved if not used for skull base reconstruction. If not invaded by a tumor or necessary for reconstruction, the inferior and middle turbinates were preserved. Conclusion The endoscopic tri-port approach provides an excellent surgical view and wide corridor and not requires an external approach, including a gingival incision.

Surgical Anatomy for the Endoscopic Endonasal Approach to the Ventrolateral Skull Base.

The authors describe the surgical anatomy for the endoscopic endonasal approach (EEA) to the ventrolateral skull base. The ventrolateral skull base can be divided into two segments: the upper lateral and lower lateral skull base. The upper lateral skull base includes the cavernous sinus and the orbit, while the lower lateral skull base includes the petrous apex, Meckel's cave, parapharyngeal space, infratemporal fossa, etc. To gain access to the upper lateral skull base, a simple opening of the ethmoid sinus provides sufficient exposure of this area. To reach the lower lateral skull base, a transpterygoid approach, following ethmoidectomy, is a key procedure providing wide exposure of this area. Understanding of surgical anatomy is mandatory for treating ventrolateral skull base lesions via EEA. An appropriate, less-invasive approach should be applied depending on the size, location, and type of lesion.

Sellar Chondroma with Endocrine Dysfunction that Resolved after Surgery: Case Report.

Chondromas originating from the sella turcica are rare, and the most common initial symptoms are headache and visual disturbance. We describe a case of sellar chondroma with endocrine impairment as an initial manifestation that completely resolved after surgery. A 40-year-old Japanese woman with amenorrhea and galactorrhea for the last 2 years was referred to our department of neurosurgery for the evaluation of high prolactin levels and a tumor in the sella turcica. A biochemical assessment indicated endocrine dysfunction. Magnetic resonance imaging and computed tomography indicated a tumor in the sella turcica. The patient's presentation favored the preoperative diagnosis of pituitary adenoma or Rathke's cleft cyst. However, because calcification was detected, other types of tumors, such as craniopharyngioma, meningioma, and chordoma, were also considered. Endoscopic transsphenoidal surgery was performed, and the possibility of a bony tumor was recognized. Finally, the tumor was completely removed, and the histopathological findings confirmed chondroma. The postoperative course was uneventful, and endocrine function improved. Five years after surgery, the patient is doing well without pituitary insufficiency, pituitary hormone medications, or signs of tumor recurrence. In cases of sellar chondroma, endocrine dysfunction sometimes precedes other symptoms, such as headache and visual disturbance. When examining a patient with an intrasellar tumor harboring calcification, clinicians must consider the possibility of sellar chondroma. Furthermore, to the best of our knowledge, this case is the first of sellar chondroma treated with endoscopic surgery to be reported.

Gremlin, a bone morphogenetic protein antagonist, is a crucial angiogenic factor in pituitary adenoma.

Gremlin is an antagonist of bone morphogenetic protein (BMP) and a major driving force in skeletal modeling in the fetal stage. Several recent reports have shown that Gremlin is also involved in angiogenesis of lung cancer and diabetic retinopathy. The purpose of this study was to investigate the role of Gremlin in tumor angiogenesis in pituitary adenoma. Double fluorescence immunohistochemistry of Gremlin and CD34 was performed in pituitary adenoma tissues obtained during transsphenoidal surgery in 45 cases (7 PRLoma, 17 GHoma, 2 ACTHoma, and 2 TSHoma). Gremlin and microvascular density (MVD) were detected by double-immunofluorescence microscopy in CD34-positive vessels from tissue microarray analysis of 60 cases of pituitary adenomas (6 PRLoma, 23 GHoma, 22 NFoma, 5 ACTHoma, and 4 TSHoma). In tissue microarray analysis, MVD was significantly correlated with an increased Gremlin level (linear regression: P < 0.005, r (2) = 0.4958). In contrast, Gremlin expression showed no correlation with tumor subtype or Knosp score. The high level of expression of Gremlin in pituitary adenoma tissue with many CD34-positive vessels and the strong coherence of these regions indicate that Gremlin is associated with angiogenesis in pituitary adenoma cells.

Fascia patchwork closure for endoscopic endonasal skull base surgery.

With the development of endoscopic technology and surgery, resection of midline skull base tumors has been achieved using endoscopic endonasal skull base (EESB) approaches. EESB approaches reportedly have a greater risk of postoperative cerebrospinal fluid (CSF) leakage. Recently, the introduction of the nasoseptal flap (NSF) decreased dramatically the incidence of CSF leakage, but the use of an NSF increases the risk of disturbing the function of the nose. Here, we report our new technique called "fascia patchwork closure" for closure after EESB surgery and its outcome. All 48 cases involved midline skull base tumors resected via EESB approaches. Of them, 32 cases were closed by the fascia patchwork technique after tumor resection, and there was no incidence of CSF leakage. Moreover, 6 of the 32 cases were closed without the use of an NSF, indicating that the fascia patchwork closure approach is effective as part of a multilayer closure for the prevention of CSF leakage. The establishment and popularization of this technique might result in the further development of EESB surgery and also an improvement of postoperative nasal function.

Endoscopic transsphenoidal cisternostomy for nonneoplastic sellar cysts.

Background and Importance. Sellar arachnoid cysts and Rathke's cleft cysts are benign lesions that produce similar symptoms, including optochiasmatic compression, pituitary dysfunction, and headache. Studies have reported the use of various surgical treatment methods for treating these symptoms, preventing recurrence, and minimizing operative complications. However, the postoperative cerebrospinal fluid (CSF) fistula and recurrence rate remain significant. Clinical Presentation. In this paper, we present 8 consecutive cases involving arachnoid cysts and Rathke's cleft cysts, which were managed by using drainage and cisternostomy, the intentional fenestration of the cyst into the subarachnoid space, and then meticulously closing sellar floor using dural sutures. The postoperative images, CSF fistula rate, and the recurrence rate were favorable. Conclusion. We report this technique and discuss the benefit of this minimally invasive approach.

Pulsed Laser-induced Liquid Jet System for Treatment of Sellar and Parasellar Tumors: Safety Evaluation.

OBJECTIVE: The pulsed laser-induced liquid jet (LILJ) system is an emerging surgical instrument intended to assist both maximal removal of the lesion and functional maintenance through preservation of fine vessels and minimal damage to the surrounding tissue. The system ejects the minimum required amount of pulsed water through a handy bayonet-shaped catheter. We have already shown a significant increase in removal rate, in addition to a noteworthy reduction of intraoperative blood loss and procedure time in the treatment of large pituitary and skull base tumors in a single-institution series. The present study evaluated the safety of the system in multiple institutions. METHODS: The study included 46 patients, 29 men and 17 women (mean age: 59.1 years) who underwent microsurgical/endoscopic resection of lesions in or in the vicinity of the pituitary fossa through the transsphenoidal approach between October 2011 and June 2012 at six institutions. The histologic diagnoses were pituitary adenoma (31 cases), meningioma (4), craniopharyngioma (3), cavernous angioma (2), and Rathke cyst cleft (1). Lesion volume ranged from 2.0 to 30.4 cm³ (mean: 3.7 cm³). Cavernous sinus invasion was observed in 11 cases and suprasellar extension in 29 cases. RESULTS: Preservation of intralesional arteries (diameter: 150 µm) was achieved in all situations in > 80% of cases. Intended surgical steps were achieved except for some restrictions in motion due to the use of an optical quartz fiber. No complications occurred directly related to the use of the device. CONCLUSIONS: The LILJ system can be used for safe removal of lesions in or in the vicinity of the pituitary fossa.

Endoscopic endonasal skull base surgery: advantages, limitations, and our techniques to overcome cerebrospinal fluid leakage: technical note.

In recent years, resections of midline skull base tumors have been conducted using endoscopic endonasal skull base (EESB) approaches. Nevertheless, many surgeons reported that cerebrospinal fluid (CSF) leakage is still a major complication of these approaches. Here, we report the results of our 42 EESB surgeries and discuss the advantages and limits of this approach for resecting various types of tumors, and also report our technique to overcome CSF leakage. All 42 cases involved midline skull base tumors resected using the EESB technique. Dural incisions were closed using nasoseptal flaps and fascia patch inlay sutures. Total removal of the tumor was accomplished in seven pituitary adenomas (33.3%), five craniopharyngiomas (62.5%), five tuberculum sellae meningiomas (83.3%), three clival chordomas (100%), and one suprasellar ependymoma. Residual regions included the cavernous sinus, the outside of the intracranial part of the internal carotid artery, the lower lateral part of the posterior clivus, and the posterior pituitary stalk. Overall incidence of CSF leakage was 7.1%. Even though the versatility of the approach is limited, EESB surgery has many advantages compared to the transcranial approach for managing mid-line skull base lesions. To avoid CSF leakage, surgeons should have skills and techniques for complete closure, including use of the nasoseptal flap and fascia patch inlay techniques.

Treatment of pituitary carcinomas and atypical pituitary adenomas: a review.

Atypical pituitary adenomas (APAs) are aggressive tumors, harboring a Ki-67 (MIB-1) staining index of 3% or more, and positive immunohistochemical staining for p53 protein, according to the World Health Organization (WHO) classification in 2004. Pituitary carcinomas (PC) usually develop from progressive APAs and predominantly consist of hormone-generating tumors, defined by the presence of disseminations in the cerebrospinal system or systemic metastases. Most of the cases with these malignant pituitary adenomas underwent surgeries, irradiations and adjuvant medical treatments, nevertheless, the therapies are mainly palliative. Recently, the efficacy of temozolomide (TMZ), an orally administered alkylating agent, has been reported as an alternative medical treatment. However, some recent studies have demonstrated a significant recurrence rate after effective response to TMZ. Further clinical and pathological researches of malignant pituitary adenomas will be required to improve the outcome of patients with these tumors.

Endocan, a new invasion and angiogenesis marker of pituitary adenomas.

Angiogenesis plays a crucial role in tumor growth. Recently, endocan has emerged as a new marker of vascular endothelial cells from cancers in other organs. In this study, we elucidated the relationship between endocan expression and tumor invasion of pituitary adenoma. Tumor tissues were obtained from 70 patients with pituitary adenoma and were examined using fluorescence immunohistochemistry. Tissue samples included 4 adrenocorticotrophic hormone producing adenomas, 10 growth hormone-producing adenomas, 49 clinically nonfunctioning adenomas, 6 prolactin producing adenomas, and 1 thyroid-stimulating hormone producing adenoma. Endocan was exclusively expressed in CD34-positive vascular endothelial cells, with over 90 % colocalization. The CD34 expression was significantly elevated with endocan expression (linear regression slope, 1.200; r(2) = 0.268, F = 23.08, p < 0.0001). As a percentage of CD34 expression, endocan expression was elevated in a Knosp grading dependent manner (Spearman's r-value, 0.651; p < 0.0001), and was also significantly elevated in macroadenomas compared with microadenomas (p = 0.0133). However, no differences in endocan expression were observed between hormonal subtypes (p = 0.066; Kruskal-Wallis test), age (Spearman's rank correlation test, p = 0.4909), or sex (Mann-Whitney test, p = 0.1701). These data show that endocan is closely related to tumor angiogenesis, and may predict tumor invasion into neighboring cavernous sinuses in pituitary adenomas.

Endoscopic endonasal skull base surgery: advantages, limitations, and our techniques to overcome cerebrospinal fluid leakage: technical note.

In recent years, resections of midline skull base tumors have been conducted using endoscopic endonasal skull base (EESB) approaches. Nevertheless, many surgeons reported that cerebrospinal fluid (CSF) leakage is still a major complication of these approaches. Here, we report the results of our 42 EESB surgeries and discuss the advantages and limits of this approach for resecting various types of tumors, and also report our technique to overcome CSF leakage. All 42 cases involved midline skull base tumors resected using the EESB technique. Dural incisions were closed using nasoseptal flaps and fascia patch inlay sutures. Total removal of the tumor was accomplished in seven pituitary adenomas (33.3%), five craniopharyngiomas (62.5%), five tuberculum sellae meningiomas (83.3%), three clival chordomas (100%), and one suprasellar ependymoma. Residual regions included the cavernous sinus, the outside of the intracranial part of the internal carotid artery, the lower lateral part of the posterior clivus, and the posterior pituitary stalk. Overall incidence of CSF leakage was 7.1%. Even though the versatility of the approach is limited, EESB surgery has many advantages compared to the transcranial approach for managing mid-line skull base lesions. To avoid CSF leakage, surgeons should have skills and techniques for complete closure, including use of the nasoseptal flap and fascia patch inlay techniques.

Molecular status of pituitary carcinoma and atypical adenoma that contributes the effectiveness of temozolomide.

There have been several reports of temozolomide (TMZ) treatment of pituitary carcinomas and atypical adenomas. O(6)-methyl-guanine-DNA methyltransferase is not the sole molecule determining the sensitivity to TMZ in pituitary carcinomas and atypical adenomas. The Japan Society of Hypothalamic and Pituitary Tumors study suggests that MSH6, one of mismatch repair pathway enzyme, fulfills a contributory role to the efficacy of TMZ treatment for pituitary carcinomas and atypical adenomas. The preserved MSH6 function might be essential for the responsiveness to TMZ treatment in pituitary carcinomas and atypical adenomas.

Clinicopathological and molecular histochemical review of skull base metastasis from differentiated thyroid carcinoma.

Skull base metastasis from differentiated thyroid carcinoma including follicular thyroid carcinoma (FTC) and papillary thyroid carcinoma (PTC) is a rare clinical entity. Eighteen FTC cases and 10 PTC cases showing skull base metastasis have been reported. The most common symptom of skull base metastasis from FTC and PTC is cranial nerve dysfunction. Bone destruction and local invasion to the surrounding soft tissues are common on radiological imaging. Skull base metastases can be the initial clinical presentation of FTC and PTC in the presence of silent primary sites. The possibility of skull base metastasis from FTC and PTC should be considered in patients with the clinical symptoms of cranial nerve dysfunction and radiological findings of bone destruction. A variety of genetic alterations in thyroid tumors have been identified to have a fundamental role in their tumorigenesis. Molecular histochemical studies are useful for elucidating the histopathological features of thyroid carcinoma. Recent molecular findings may provide novel molecular-based treatment strategies for thyroid carcinoma.