Smruti K. Patel

Surgical nuances for removal of tuberculum sellae meningiomas with optic canal involvement using the endoscopic endonasal extended transsphenoidal transplanum transtuberculum approach

Tuberculum sellae meningiomas frequently extend into the optic canals. Radical tumor resection including the involved dural attachment, underlying hyperostotic bone, and intracanalicular tumor in the optic canal offers the best chance of a Simpson Grade I resection to minimize recurrence. Decompression of the optic canal with removal of the intracanalicular tumor also improves visual outcome since this portion of the tumor is usually the cause of asymmetrical visual loss. The purely endoscopic endonasal extended transsphenoidal approach offers a direct midline trajectory and immediate access to tuberculum sellae meningiomas without brain retraction and manipulation of neurovascular structures. Although the endoscopic approach has been previously criticized for its inability to remove tumor within the optic canals, complete Simpson Grade I tumor removal including intracanalicular tumor, dural attachment, and involved hyperostotic bone can be achieved in properly selected patients. Excellent visualization of the suprasellar region and the inferomedial aspects of both optic canals allows for extracapsular, extraarachnoid dissection of the tumor from the critical structures using bimanual microsurgical dissection. In this report, the authors describe the operative nuances for removal of tuberculum sellae meningiomas with optic canal involvement using a purely endoscopic endonasal extended transsphenoidal (transplanum transtuberculum) approach. They specifically highlight the technique for endonasal bilateral optic nerve decompression and removal of intracanalicular tumor to improve postoperative visual function, as demonstrated in 2 illustrative cases. Special attention is also given to cranial base reconstruction to prevent CSF leakage using the vascularized pedicled nasoseptal flap.

Surgical nuances for removal of retrochiasmatic craniopharyngioma via the endoscopic endonasal extended transsphenoidal transplanum transtuberculum approach

Retrochiasmatic craniopharyngiomas are challenging tumors to remove given their deep location and proximity to critical neurovascular structures. Complete surgical removal offers the best chance of cure and prevention of recurrence. The endoscopic endonasal extended transsphenoidal approach offers direct midline access to the retrochiasmatic space through a transplanum transtuberculum corridor. Excellent visualization of the undersurface of the optic chiasm and hypothalamus can be obtained to facilitate bimanual extracapsular dissection to permit complete removal of these formidable tumors. In this report the authors review the endoscopic endonasal extended transsphenoidal approach, with specific emphasis on technical operative nuances in removing retrochiasmatic craniopharyngiomas. An illustrative intraoperative video demonstrating the technique is also presented.

A gender-based comparison of academic rank and scholarly productivity in academic neurological surgery

The number of women pursuing training opportunities in neurological surgery has increased, although they are still underrepresented at senior positions relative to junior academic ranks. Research productivity is an important component of the academic advancement process. We sought to use the h-index, a bibliometric previously analyzed among neurological surgeons, to evaluate whether there are gender differences in academic rank and research productivity among academic neurological surgeons. The h-index was calculated for 1052 academic neurological surgeons from 84 institutions, and organized by gender and academic rank. Overall men had statistically higher research productivity (mean 13.3) than their female colleagues (mean 9.5), as measured by the h-index, in the overall sample (p<0.0007). When separating by academic rank, there were no statistical differences (p>0.05) in h-index at the assistant professor (mean 7.2 male, 6.3 female), associate professor (11.2 male, 10.8 female), and professor (20.0 male, 18.0 female) levels based on gender. There was insufficient data to determine significance at the chairperson rank, as there was only one female chairperson. Although overall gender differences in scholarly productivity were detected, these differences did not reach statistical significance upon controlling for academic rank. Women were grossly underrepresented at the level of chairpersons in this sample of 1052 academic neurological surgeons, likely a result of the low proportion of females in this specialty. Future studies may be needed to investigate gender-specific research trends for neurosurgical residents, a cohort that in recent years has seen increased representation by women.

Triple-Layer Reconstruction Technique for Large Cribriform Defects After Endoscopic Endonasal Resection of Anterior Skull Base Tumors

Endoscopic endonasal transcribriform (EET) resection of anterior skull base (ASB) tumors results in large defects that may extend the entirety of the cribriform plate. Endoscopic repair of these cribriform defects can often be challenging. We describe our reconstruction technique for large ASB defects after EET resection of ASB tumors. This triple‐layer technique is comprised of autologous fascia lata, acellular dermal allograft, and a vascularized pedicled nasoseptal flap (PNSF). The technique is described and postoperative cerebrospinal fluid (CSF) leak rate is evaluated.

Celebrating the golden anniversary of anterior skull base surgery: Reflections on the Past 50 Years and Its Historical Evolution†

With its inception nearly half a century ago through the pioneering work of Dandy, McLean, and Smith, anterior skull base (ASB) surgery is a relatively young discipline. It became a distinct entity in 1963 when Ketcham popularized the combined transcranial transfacial approach for en bloc resection of tumors of the paranasal sinuses extending into the anterior cranial fossa. However, because these procedures resulted in major morbidities and mortalities, alternative modes of treatment were sought. Since the 1970s, the introduction and promotion of the surgical endoscope by Messerklinger, Stammberger, and Kennedy, commenced the era of endoscopic sinus surgery. Thaler and colleagues described the utility of the endoscope for ASB surgery at the turn of the century. This allowed direct visualization and safer, more accurate removal of tumors. In 2001, Casiano reported the first purely endoscopic endonasal ASB resection, a novel technique that has been adopted by major skull base centers. The success of ASB surgery can be attributed to both the development of the skull base team as well as improvements in surgical techniques, instrumentation, and visualization technology. In this article, we review the historical evolution of ASB surgery as we approach the 50th anniversary since its recognition as a distinct entity. Laryngoscope, 2013

Norman Dott, Gerard Guiot, and Jules Hardy: key players in the resurrection and preservation of transsphenoidal surgery.

Developed over a century ago, the transsphenoidal approach to access lesions of the pituitary gland and sella turcica has transformed the field of neurosurgery, largely due to the work of Oskar Hirsch and Harvey Cushing. Furthermore, its use and modification in the early 1900s was perhaps one of Cushings greatest legacies to skull base surgery. However, Cushing, who had worked relentlessly to improve the transsphenoidal route to the pituitary region, abandoned the approach by 1929 in his pursuit to master transcranial approaches to the suprasellar region. Hirsch and a few other surgeons continued to perform transsphenoidal operations, but they were unable to maintain the popularity of the approach among their peers. During a time when transsphenoidal surgery was on the brink of extinction, a critical lineage of 3 key surgeons--Norman Dott, Gerard Guiot, and Jules Hardy--would resurrect the art, each working to further improve the procedure. Dott, Cushings apprentice from 1923 to 1924, brought his experiences with transsphenoidal surgery to Edinburgh, Scotland, and along the way, developed the lighted nasal speculum to provide better illumination in the narrow working area. Guiot, inspired by Dott, adopted his technique and used intraoperative radiofluoroscopic technique for image guidance. Hardy, a fellow of Guiot, from Montreal, Canada, revolutionized transsphenoidal microsurgery with the introduction of the binocular microscope and selective adenomectomy. The teachings of these pioneers have endured over time and are now widely used by neurosurgeons worldwide. In this paper, we review the lineage and contributions of Dott, Guiot, and Hardy who served as crucial players in the preservation of transsphenoidal surgery.

From above or below: The controversy and historical evolution of tuberculum sellae meningioma resection from open to endoscopic skull base approaches

In the early 20th century, the first successful surgical removal of a tuberculum sellae meningioma (TSM) was performed and described by Harvey Cushing. It soon became recognized that TSM pose a formidable challenge for skull base surgeons because of their deep and sensitive location, proximity to critical neurovascular elements, and often dense and fibrous nature. Because of this, over the next several decades controversy transpired regarding their optimal method of resection. Early attempts involved utilization of open transcranial routes. This included classic bilateral and unilateral frontal approaches, followed by pterional or frontotemporal approaches, which have evolved to incorporate skull base modifications, such as the supraorbital, orbitozygomatic, and orbitopterional approaches. Minimally invasive supraorbital keyhole approaches through eyebrow incisions have also been adopted. Over the past 25 years, the microsurgical transsphenoidal approach, classically used for pituitary and parasellar tumors, was modified to resect suprasesllar TSM via the extended transsphenoidal approach. More recently, with the evolution of endoscopic techniques, resection of TSM has been achieved using purely endoscopic endonasal transplanum transtuberculum approaches. Although each of these techniques has been successfully described for the treatment of TSM, the question still remains: is it better to access and operate on these lesions via a traditional, transcranial avenue, or are they better treated via endoscopic endonasal techniques? We outline the surgical management of TSM through history, from early transcranial and transsphenoidal approaches to modern extended endoscopic endonasal procedures. We briefly explore the arguments favoring each of the methods and the advancements which have emerged to further optimize surgical resection.

Overview and History of Trigeminal Neuralgia

Although the symptoms associated with trigeminal neuralgia have been well documented, the root cause of this disease initially eluded most surgeons. Although early remedies were haphazard because of a lack of understanding about the condition, near the 20th century both medical and procedural therapies were established for the treatment of trigeminal neuralgia. These treatments include a variety of medications, chemoneurolysis, radiofrequency lesioning, percutaneous ablative procedures, stereotactic radiosurgery, and open rhizotomy and microvascular decompression. This report recounts the history of trigeminal neuralgia, from its earliest descriptions to the historical evolution of nonsurgical and surgical therapies.

Giant Suprasellar Rathke's Cleft Cyst Mimicking Craniopharyngioma: Implications for a Spectrum of Cystic Epithelial Lesions of Ectodermal Origin

Cystic epithelial lesions such as Rathkes 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.

Utility of a rotation–suction microdebrider for tumor removal in endoscopic endonasal skull base surgery

The microdebrider is a common tool used in endoscopic sinus surgery for removing polypoid and sinonasal tissue. It uses rotating blades and an integrated suction device for controlled removal of tissue under video-endoscopic visualization. To our knowledge, the application of the microdebrider for endoscopic removal of skull base tumors has not been reported. This study aimed to investigate the utility of the rotation-suction microdebrider as a tool for endoscopic endonasal removal of solid and fibrous skull base tumors. Thirty-two patients underwent endoscopic endonasal skull base surgery where the rotation-suction microdebrider was used as the primary tool for tumor removal and debulking. Pathologies included a variety of anterior skull base meningiomas, sinonasal skull base malignancies, juvenile nasopharyngeal angiofibromas, schwannomas, and other skull base lesions. Gross total and near total removal was achieved in 87.5% (28/32) of patients, and subtotal removal was performed in 12.5% (4/32) of patients. The microdebrider allowed efficient debulking and removal of solid and fibrous tumors, such as meningiomas, that were not responsive to standard ultrasonic aspiration. There were no complications of orbital or neurovascular injury, or thermal injury to the nostril. The rotation-suction microdebrider is a useful tool for endoscopic endonasal removal of skull base tumors. This is particularly useful for solid and fibrous tumors that are not responsive to standard ultrasonic aspiration. For intracranial tumors, it is critical to remain inside the tumor capsule during debulking so as to avoid injury to the surrounding neurovascular structures.