Faculty Bibliography

Cystic epithelial lesions such as Rathke's cleft cysts (RCCs) and craniopharyngiomas may be difficult to distinguish on a clinical, radiographic, and sometimes histopathological basis. We describe a case of a giant 6.5 cm suprasellar cystic lesion that was presumed to be a craniopharyngioma based on the neuroimaging findings. The lesion extended from the anterior skull base and sella turcica to the lateral ventricle and sylvian fissure resulting in obstructive hydrocephalus. Complete surgical removal of the suprasellar lesion was achieved using an extended frontotemporal transbasal skull base approach. Intraoperatively, the cyst wall was thickened and partially calcified, resembling a craniopharyngioma. However, the histopathological examination revealed findings most consistent with a RCC with additional features of extensive squamous metaplasia, metaplastic bone formation, and chronic inflammation. The case raises the issue of whether there is a pathologic continuum of parasellar ectodermal lesions which may account for the overlap of features and transitional states. In this report, we discuss the possible spectrum between RCCs and craniopharyngiomas, and also emphasize the importance of complete resection of the cyst wall in RCCs that exhibit squamous metaplasia, inflammation, or ossification to minimize the probability of recurrence.

A little over a century ago, in 1907, at the University of Innsbruck, Hermann Schloffer performed the first transsphenoidal surgery on a living patient harboring a pituitary adenoma. Schloffer used a superior nasal route via a transfacial lateral rhinotomy incision. This was perhaps his greatest academic contribution to neurosurgery. Despite the technological limitations of that time, Schloffer's operation was groundbreaking in that it laid the foundation for future development and refinement of transsphenoidal pituitary surgery, influencing prominent surgeons such as Oskar Hirsch and Harvey Cushing. Even after undergoing multiple modifications and a brief fall into obscurity, the transsphenoidal approach has endured through generations of surgeons and remains the preferred approach for lesions of the sella turcica to this day. Although Schloffer performed primarily abdominal surgery in his practice, his contributions to the transsphenoidal approach have had a lasting impact in the field of pituitary and skull base surgery. The authors review the life and career of Hermann Schloffer, the surgical details of his transsphenoidal operation, and the legacy that it has left on the field of pituitary surgery.

OBJECTIVES/HYPOTHESIS: The endoscopic endonasal transcribriform approach (EETA) is a viable alternative option for resection of selected anterior skull base (ASB) tumors. However, this technique results in the creation of large cribriform defects. Some have reported the use of a rigid substitute for ASB reconstruction to prevent postoperative frontal lobe sagging. We evaluate the degree of frontal lobe sagging using our triple-layer technique [fascia lata, acellular dermal allograft, and pedicled nasoseptal flap (PNSF)] without the use of rigid structural reconstruction for large cribriform defects. STUDY DESIGN: Retrospective analysis. METHODS: Nine patients underwent an EETA for resection of large ASB tumors from August 2010 to November 2011. The degree of frontal lobe displacement after EETA, defined as the ASB position, was calculated based on the most inferior position of the frontal lobe relative to the nasion-sellar line defined on preoperative and postoperative imaging. A positive value signified upward displacement, and a negative value represented inferior displacement of the frontal lobe. RESULTS: The average cribriform defect size was 9.3 cm(2) (range, 5.0-13.8 cm(2) ). The average distance of postoperative frontal lobe displacement was 0.2 mm (range, -3.9 to 2.9 mm) without any cases of significant brain sagging. The mean follow-up period was 10.1 months (range, 4-19 months). There were no postoperative CSF leaks. CONCLUSIONS: Rigid structural repair may not be necessary for ASB defect repair after endoscopic endonasal resection of the cribriform plate. Our technique for multilayer cranial base reconstruction appears to be satisfactory in preventing delayed frontal lobe sagging.

BACKGROUND: High-grade dural arteriovenous fistulas (DAVFs) with retrograde cortical leptomeningeal drainage are formidable lesions because of their risk for intracranial hemorrhage. Treatment is aimed at occluding venous outflow to achieve obliteration of the fistula. In DAVFs that involve a large dural venous sinus (transverse sigmoid sinus or superior sagittal sinus), occluding venous outflow can be accomplished endovascularly with transvenous embolization. However, in some cases of DAVFs with reflux into cortical leptomeningeal veins, there may be venous restrictive disease downstream, such as occlusive thrombosis, which can prohibit endovascular access via the transfemoral or transjugular routes. In these instances, a transcranial approach can be performed to expose the large dural venous sinus distal to the site of occlusion for direct catheterization of the venous outflow for transvenous embolization. This combined surgical and endovascular strategy provides direct access to the venous outflow and bypasses the site of thrombotic obstruction. METHODS: In this report, we describe our technique of single stage surgically-assisted transvenous embolization in three patients with high-grade DAVFs involving a large dural sinus. RESULTS: All patients achieved complete obliteration of their DAVFs without any venous related complications. CONCLUSION: Our technique of surgically-assisted direct transvenous embolization of high-grade DAVFs can be successfully performed as a single stage in the operating room with intraoperative angiography and stereotactic image guidance.

PURPOSE: Persistent cerebrospinal fluid (CSF) rhinorrhea after open skull base surgery can be challenging to manage due to the risk of meningitis, brain abscess, surgical morbidity associated with revision craniotomy, and the lack of available healthy autologous tissue after failure of a pericranial flap. Given the recent success of the vascularized pedicled nasoseptal flap (PNSF) for reconstruction after endoscopic skull base surgery, we have adopted this technique as a salvage method to treat recalcitrant CSF rhinorrhea after previous open skull base surgery in order to avoid revision craniotomy. To our knowledge, use of the PNSF in this setting has not been previously described in the literature. METHODS: A retrospective analysis was performed on 4 patients who underwent endoscopic endonasal PNSF repair of persistent CSF rhinorrhea after having undergone previous open transcranial skull base operation. Pathologies consisted of one sinonasal anterior skull base squamous cell carcinoma, one recurrent petrosal skull base meningioma, and 2 traumatic gunshot wounds to the head. RESULTS: All 4 patients underwent successful repair of CSF rhinorrhea without complications using the salvage endoscopic endonasal PNSF technique after a mean follow-up of 21.5 months. CONCLUSIONS: In patients who have undergone previous open skull base surgery as the primary approach, persistent CSF rhinorrhea can be safely repaired using the vascularized PNSF via an endoscopic endonasal approach. This minimally invasive strategy has the advantage of providing new healthy vascularized tissue for skull base reconstruction while avoiding revision craniotomy.

The pineal gland has been studied through philosophy and science for thousands of years. Its role in human physiology was not well understood until the scientific community first started to report on pineal pathology in the eighteenth century. Throughout the nineteenth and twentieth centuries, reports on pineal tumors and the emergence of comparative anatomy allowed more complete understanding of pineal function. Neurosurgical methods of treating pineal pathology first emerged in the early twentieth century. In the latter half of the twentieth century, the emergence of microsurgical technique allowed for excellent outcomes with minimal morbidity and mortality.