The evolution of extracranial approaches to the pituitary and anterior skull base

The Evolution of Pituitary Gland Surgery from the Ancients to the Millennials

Located at the base of the skull, the pituitary gland has a long and controversial history, not only in terms of its anatomy, but especially in the functions it performs and in the attempt to approach it surgically. Considered by Galen of Pergamon to have a role in releasing waste products of the brain, a theory accepted until the 17th century, the pituitary gland became a separate entity once with the anatomical descriptions of the famous Andreas Vesalius. At the beginning of the 18th century, researches of the time began to be more and more interested in this gland, trying to identify its functions, and at the same time correcting the traditional theories that were wrong or incomplete. Later, they turned their attention to experimental animal studies that represented the germinal nucleus for the transcranial and endoscopic pituitary surgery. In this review, an attempt has been made to record the entire history of anatomy, physiology and surgery of the pituitary gland, from antiquity to the current day's surgical techniques.

Comparison of the endoscopic endonasal to microscopic sublabial transsphenoidal approach in a case series of pituitary macroadenomas

For a number of years, the microscopic sublabial transsphenoidal (MST) approach was considered the gold standard approach for the treatment of pituitary macroadenomas. Nonetheless, the trend is currently shifting away from the MST to the endonasal transsphenoidal (EET) approach. The aim of the present study was to examine the post-operative outcomes of the first cases operated by a team of two young surgeons using the EET approach, compared to the cases operated by a team of senior neurosurgeons with extensive experience with the MST approach. For this purpose, data from 20 patients with pituitary adenoma were retrospectively collected from a single center who were operated by the current and previous pituitary-surgery teams. All the patients who presented with visual impairment in the EET group recovered completely (5/5), whereas 4/5 patients in the MST group recovered completely. Primary hospitalization duration was similar in the two groups. Gross tumor removal was achieved in 90% of patients in the EET group compared to 70% of the patients operated with the MST technique. Intraoperative complications were comparable between the two groups. The first cases operated at the center with EET proved to have better visual outcomes and a larger tumor removal when compared to the MST group. A greater experience in using this technique could exponentiate the differences in the post-operative outcomes, such as a lower hospitalization duration and fewer intraoperative complications. On the whole, colleagues who have yet to familiarize themselves with the EET approach could perhaps be encouraged to learn to utilize this technique, provided that their center is staffed with an experienced team of skull base surgeons to intervene in an intraoperative complication.

Craniofacial resection of malignant tumors of the anterior skull base: a case series and a systematic review

BACKGROUND

Craniofacial resection (CFR) is still considered as the gold standard for managing sinonasal malignancies of the anterior skull base (ASB), while endoscopic approaches are gaining credibility. The goal of this study was to evaluate outcomes of patients who underwent CFR at our institution and to compare our results to international literature.

METHOD

Retrospective analysis of all patients undergoing CFR between 1995 and 2017, and systematic literature review according to the PRISMA statement.

RESULTS

Forty-one patients with sinonasal malignancy (81% with stage T4) of the ASB were included. There was no operative mortality. Complications were observed in 9 cases. We obtained 100% follow-up with mean observation of 100 months. Disease-specific survival rates were 90%, 74%, and 62% and recurrence-free survival was 85% at two, 72% at five, and 10 years follow-up, respectively. CFR as primary treatment, en bloc resection, and resection with negative margins correlated to better survival. Recursive partition analysis identified the latter as the most important prognostic factor, regardless of surgical technique. The relative risk of non-radicality was significantly higher after piecemeal resection compared to en bloc resection. Compared to 15 original articles, totaling 2603 patients, eligible for review, the present study has the longest follow-up time, the second highest 5-year OS, and the third highest 5-year DSS, despite having a higher proportion of patients with high-stage disease.

CONCLUSION

CFR in true en bloc fashion can still be considered as the treatment of choice in cases of advanced-stage sinonasal malignancies invading the ASB.

Pituitary adenomas: historical perspective, surgical management and future directions

Pituitary adenomas are among the most common central nervous system tumors. They represent a diverse group of neoplasms that may or may not secrete hormones based on their cell of origin. Epidemiologic studies have documented the incidence of pituitary adenomas within the general population to be as high as 16.7%. A growing body of work has helped to elucidate the pathogenesis of these tumors. Each subtype has been shown to demonstrate unique cellular changes potentially leading to tumorigenesis. Surgical advancements over several decades have included microsurgery and the employment of the endoscope for surgical resection. These advancements increase the likelihood of gross-total resection and have resulted in decreased patient morbidity.

A learning curve of endoscopic transsphenoidal surgery for pituitary adenoma

Experience is an important point in the effectiveness of the surgical procedure and in the reduction of complications in pituitary surgery. Endoscopic pituitary surgery differs from microscopic surgery because it requires a steep learning curve for endoscopic skills. In this study, we investigated the learning curve of endoscopic transsphenoidal pituitary surgery in our department. Endoscopic transsphenoidal operations were performed on 80 patients, who were retrospectively examined and grouped as the early and late experience groups to evaluate the learning curve. The patients' characteristics, gross total resection, endocrinological cure, visual field improvement, duration of surgery, postoperative hospital stay, and complications were noted. After examining our patients of the 2 groups of period, our experience showed that as the effectiveness of endoscopic surgery increases, the duration of surgery and postoperative hospital stay decrease. In this study, we identified a learning curve in endoscopic pituitary surgery.

Minimally invasive pediatric neurosurgery

Advances in technology have facilitated the development of minimally invasive neurosurgical options for the treatment of pediatric neurological disease. This review seeks to familiarize pediatric neurologists with some of the techniques of minimally invasive pediatric neurosurgery, focusing on treatments for hydrocephalus, arachnoid cysts, intracranial mass lesions, and craniosynostosis.

The transition from microscopic to endoscopic transsphenoidal surgery: the experience at Brigham and Women's Hospital

OBJECTIVE

As interest and enthusiasm for the use of the endoscope in transsphenoidal anterior skull base and pituitary surgery increases, neurosurgeons are increasingly adopting endoscopic technology and associated novel concepts. Often this involves a transition from the standard operating microscope as the main means of visualization to the operating endoscope (2D or 3D) during surgery.

METHODS

The authors' experience with this transition is described, including the rationale, advantages and disadvantages of the two surgical techniques.

RESULTS

The successful use of endoscopic surgery for a large variety of pathological problems involving the anterior skull base and the pituitary region is presented. Perceived advantages for the patient and the surgeon are described, as is the occasional need for transition back to the microscopic approach.

CONCLUSIONS

The endoscopic approach and its allied technology are here to stay. They are useful and occasionally preferable methods for treating a variety of suitable lesions involving the anterior skull base. The importance of incorporating the basic principles of skull base surgery is emphasized.

Expanding neurosurgery

The history of medicine is replete with innovations in neurosurgery that have spurred further developments across the medical spectrum. Surgeons treating pathologies in the head and spine have broken ground with new approaches, techniques, and technologies since ancient times. Neurosurgeons occupy a vital nexus in patient care, interfacing with the clinical symptoms and signs afflicting patients, the pathology at surgery, and imaging studies. No other physicians occupy this role within the nervous system. This power of observation and the ability to intercede place neurosurgeons in a unique position for impacting disease. Yet despite these pioneering achievements, more recently, forces in the workplace may be challenging neurosurgery's opportunities to contribute to the future growth of the neurosciences and medicine. The authors posit that, in the current health care climate, revenue generation by neurosurgical clinical activity is valued by the system more than neurosurgical research and academic output. Without providing the talented stream of new neurosurgeons with the opportunities and, in fact, the directive to achieve beyond simple financial success, the specialty is missing the opportunity to optimize its progress. The authors contend that the key to remaining relevant with the incorporation of new technologies to the treatment of neurosurgical patients will be to be flexible, open-minded, and nimble with the adaptation of new procedures by training and encouraging neurosurgical residents to pursue new or neglected areas of the specialty. Only by doing so can neurosurgery continue to expand.

Marching beyond the sella: Gerard Guiot and his contributions to neurosurgery

Gerard Guiot (1912-1998) was one of the most renowned and innovative neurosurgeons of the 20th century. His pivotal and revolutionary role in advancing transsphenoidal surgery has been recorded in many historical vignettes, yet his outstanding contributions to the advancement of neurosurgery outside the confines of the sella have not been described in a detailed fashion. In this article, the authors discuss the life and achievements of Professor Guiot and present a comprehensive description of his contributions to the field of neurosurgery, including cerebrovascular, spine, craniofacial, stereotactic functional, and endoscopic surgery.

Endoscopic anatomy of sellar region

The transsphenoidal approach is the preferred access used in surgical treatment of most sellar region pathologies. The use of endoscopy is advantageous, and it is considered a good alternative to the traditional microsurgical technique. The purpose of this study is to recognize and describe anatomical variations of the sphenoid sinus and the sellar region, mainly describing the anatomy of the posterior wall of the sphenoid sinus and analyzing intercarotid distances in 3 regions. Thirty sphenoid blocks treated with formaldehyde were injected and dissected. Using endoscopy, anatomical variations were studied and the intercarotid distances were measured at the tuberculum sellae, sellar floor and clivus. The types of sphenoid sinus found were: conchal in 1 (4.76 %), pré-sellar in 2 (9.52 %) and sellar in 19 (85.7 %) specimens. The mean distance found from the sphenoid sinus ostium to the sella turcica was 19 mm (±6.5) mm. The mean intercarotid distances found at the tuberculum sellae, sellar floor and clivus were respectively 13.32, 18.00 and 18.90 mm. Endoscopy, with its magnification and lighting provide a panoramic view of deep fields. The anatomical variations described in this study support the need for a careful evaluation of preoperative images in each case.

Craniofacial resection and its role in the management of sinonasal malignancies

Sinonasal malignancy is rare, and its presentation is commonly late. There is a wide variety of pathologies with varying natural histories and survival rates. Anatomy of the skull base is extremely complex and tumors are closely related to orbits, frontal lobes and cavernous sinus. Anatomical detail and the late presentation render surgical management a challenging task. A thorough understanding of anatomy and pathology combined with modern neuroimaging and reliable reconstruction within a multidisciplinary team is imperative to carry out skull base surgery effectively. While endoscopic approaches are gaining credibility, clearly, it will be some time before meaningful comparisons with craniofacial resection can be made. Until then, craniofacial resection will remain the gold standard for managing the sinonasal malignancies of the anterior skull base, as it has proved to be safe and effective.

Transnasal excerebration surgery in ancient Egypt

Ancient Egyptians were pioneers in many fields, including medicine and surgery. Our modern knowledge of anatomy, pathology, and surgical techniques stems from discoveries and observations made by Egyptian physicians and embalmers. In the realm of neurosurgery, ancient Egyptians were the first to elucidate cerebral and cranial anatomy, the first to describe evidence for the role of the spinal cord in the transmission of information from the brain to the extremities, and the first to invent surgical techniques such as trepanning and stitching. In addition, the transnasal approach to skull base and intracranial structures was first devised by Egyptian embalmers to excerebrate the cranial vault during mummification. In this historical vignette, the authors examine paleoradiological and other evidence from ancient Egyptian skulls and mummies of all periods, from the Old Kingdom to Greco-Roman Egypt, to shed light on the development of transnasal surgery in this ancient civilization. The authors confirm earlier observations concerning the laterality of this technique, suggesting that ancient Egyptian excerebration techniques penetrated the skull base mostly on the left side. They also suggest that the original technique used to access the skull base in ancient Egypt was a transethmoidal one, which later evolved to follow a transsphenoidal route similar to the one used today to gain access to pituitary lesions.

Elevated body mass index and risk of postoperative CSF leak following transsphenoidal surgery

OBJECT

Postoperative CSF leakage can be a serious complication after a transsphenoidal surgical approach. An elevated body mass index (BMI) is a significant risk factor for spontaneous CSF leaks. However, there is no evidence correlating BMI with postoperative CSF leak after transsphenoidal surgery. The authors hypothesized that patients with elevated BMI would have a higher incidence of CSF leakage complications following transsphenoidal surgery.

METHODS

The authors conducted a retrospective review of 121 patients who, between August 2005 and March 2010, underwent endoscopic endonasal transsphenoidal surgeries for resection of primarily sellar masses. Patients requiring extended transsphenoidal approaches were excluded. A multivariate statistical analysis was performed to investigate the association of BMI and other risk factors with postoperative CSF leakage.

RESULTS

In 92 patients, 96 endonasal endoscopic transsphenoidal surgeries were performed that met inclusion criteria. Thirteen postoperative leaks occurred and required subsequent treatment, including lumbar drainage and/or reoperation. The average BMI of patients with a postoperative CSF leak was significantly greater than that in patients with no postoperative CSF leak (39.2 vs 32.9 kg/m(2), p = 0.006). Multivariate analyses indicate that for every 5-kg/m(2) increase in BMI, patients undergoing a transsphenoidal approach for a primarily sellar mass have 1.61 times the odds (95% CI 1.10-2.29, p = 0.016, by multivariate logistic regression) of having a postoperative CSF leak.

CONCLUSIONS

Elevated BMI is an independent predictor of postoperative CSF leak after an endonasal endoscopic transsphenoidal approach. The authors recommend that patients with BMI greater than 30 kg/m(2) have meticulous sellar reconstruction at surgery and close monitoring postoperatively.

Endoscopic anatomy of the approaches to the sellar area and planum sphenoidale

The productive work between otolaryngologists and neurosurgeons has resulted in the emergence of endoscopic endonasal skull base surgery. The goal of the present study is to describe the endoscopic anatomy of the endonasal approach to the sellar region and planum sphenoidale, highlighting the key points of the surgical approach and the neurovascular landmarks.

METHOD

Descriptive study of the endoscopic endonasal dissection of 9 fresh cadavers with exposure of the anatomic structures.

RESULTS

The endoscopic endonasal ethmoidectomy and sphenoidotomy allows an expanded access to the sellar area and planum sphenoidale. The surface anatomy of the sphenoid sinus is easily identifiable and provides safe landmarks, guiding the intracranial dissection.

CONCLUSION

The endoscopic endonasal approach to the skull base by the ENT and neurosurgeon is feasible, but it requires adequate anatomical knowledge and endoscopic skills for its realization, which can be obtained by practicing in cadavers.

Pituitary surgery: legacies from the past

Pituitary surgery is a recent development in neurosurgery and most of the surgical techniques concerned have been described within the last century. We provide a historical perspective by reviewing the major steps in the development of this neurosurgical subspecialty through the ages. We concentrate on the most important figures whose advances in the study of the physiology and anatomy of the pituitary are most significant. This journey into the past will demonstrate that our current knowledge is the summation of a long road of investigation.

Endoscopic transsphenoidal pituitary surgery: evidence of an operative learning curve

BACKGROUND

The use of the fiberoptic endoscope is a recent innovation in pituitary surgery.

OBJECTIVE

To investigate the evidence of an operative learning curve after the introduction of endoscopic transsphenoidal surgery in our unit.

METHODS

The first 125 patients who underwent endoscopic transnasal transsphenoidal surgery for pituitary fossa lesions between 2005 and 2007 performed by 1 surgeon were studied. Changes in a number of parameters were assessed between 2 equal 15-month time periods: period 1 (53 patients) and period 2 (72 patients).

RESULTS

There were 67 patients (54%) with nonfunctioning adenomas, 22 (18%) with acromegaly, and 10 (8%) with Cushing's disease. Between study periods 1 and 2, there was a decrease in the mean duration of surgery for nonfunctioning adenomas (from 120 minutes to 91 minutes; P < .01). This learning effect was not apparent for functioning adenomas, the surgery for which also took longer to perform. The proportion of patients with an improvement in their preoperative visual field deficits increased over the study period (from 80% to 93%; P < .05). There were nonsignificant trends toward improved endocrine remission rates for patients with Cushing's disease (from 50% to 83%), but operative complications, notably the rates of hypopituitarism, did not change. Overall length of hospital stay decreased between time periods 1 and 2 (from 7 to 4 days median; P < .01).

CONCLUSION

The improvements in the duration of surgery and visual outcome noted after about 50 endoscopic procedures would favor the existence of an operative learning curve for these parameters. This further highlights the benefits of subspecialization in pituitary surgery.