Transsphenoidal Approach in Endoscopic Endonasal Surgery for Skull Base Lesions: What Radiologists and Surgeons Need to Know

Rathke's cleft cyst: From history to molecular genetics

A Rathke's cleft cyst (RCC) is a remnant of the embryologic Rathke's pouch and a common pituitary lesion. A true RCC is lined with ciliated cuboidal or columnar epithelia with occasional goblet cells and squamous metaplasia. A RCC is frequently diagnosed incidentally through magnetic resonance imaging and computed tomography of the brain or pituitary gland. Presentation can range from an asymptomatic clinical picture to a rapidly progressive disease. RCC are located most often in the sellar and suprasellar regions and a careful differential diagnosis is crucial, especially to exclude craniophryngioma. Recent studies illuminate novel molecular mechanisms and markers for understanding the pathogenesis of RCC. PROP-1, a paired-like homeodomain transcription factor, controls pituitary ontogeny and its high expression induces RCCs. Both transgenic mouse models and immunohistochemical analysis of human RCCs indicate that the leukemia inhibitory factor is involved in pathogenesis. The expression of cytokeratins 8 and 2 in RCCs, but not in craniopharyngiomas, and the presence of beta-catenin mutations in many craniopharyngiomas, but not in RCCs, help with the differential diagnosis. For asymptomatic and small RCCs, observation is appropriate, with serial magnetic resonance imaging and hormonal investigation depending on the patient's clinical status. Surgical resection may be required for symptomatic RCC and recurrence rates are generally low. For patients with a recurrence, stereotactic radiosurgery is an effective approach with low risk.

Skull Base Chordoma and Chondrosarcoma: Neuroradiologist's Guide to Diagnosis, Surgical Management, and Proton Beam Therapy

Skull base chordomas and chondrosarcomas are distinct types of rare, locally aggressive mesenchymal tumors that share key principles of imaging investigation and multidisciplinary care. Maximal safe surgical resection is the treatment choice for each, often via an expanded endoscopic endonasal approach, with or without multilayer skull base repair. Postoperative adjuvant radiation therapy is frequently administered, usually with particle therapy such as proton beam therapy (PBT). Compared with photon therapy, PBT enables dose escalation while limiting damage to dose-limiting neurologic structures, particularly the brainstem and optic apparatus, due to energy deposition being delivered at a high maximum with a rapid decrease at the end of the penetration range (Bragg peak phenomenon). Essential requirements for PBT following gross total or maximal safe resection are tissue diagnosis, minimal residual tumor after resection, and adequate clearance from PBT dose-limiting structures. The radiologist should understand surgical approaches and surgical techniques, including multilayer skull base repair, and be aware of evolution of postsurgical imaging appearances over time. Accurate radiologic review of all relevant preoperative imaging examinations and of intraoperative and postoperative MRI examinations plays a key role in management. The radiology report should reflect what the skull base surgeon and radiation oncologist need to know, including distance between the tumor and PBT dose-limiting structures, tumor sites that may be difficult to access via the endoscopic endonasal route, the relationship between intradural tumor and neurovascular structures, and tumor sites with implications for postresection stability. ©RSNA, 2024 Supplemental material is available for this article.

Morphometric analysis of transsphenoidal surgery in Peruvian population

Background

Transsphenoidal surgery has become a key element in the approach to skull base pathologies. The objective of the study was to explore the morphometry of the sphenoidal region in the Peruvian population, with an emphasis on understanding its specific anatomical characteristics and providing quantitative data for the planning of transsphenoidal surgery.

Methods

A cross-sectional study included a random sample of 81 cases of healthy individuals who presented to the Radiology Department of a Private Hospital Center in Peru over 1 year. Skull computed tomography scans without contrast were performed, and a detailed morphometric analysis was conducted by an expert neurosurgeon, including measurements of four parameters to evaluate the anatomy of the craniofacial region.

Results

Most participants exhibited complete sellar pneumatization, followed by incomplete sellar pneumatization, while conchal pneumatization was rare. Significant differences were found between men and women in the distance from the nasal opening to the dorsum of the sella turcica. No significant gender differences were observed in other anatomical measurements or significant changes with age in anatomical measurements.

Conclusion

Morphometric analysis provides crucial data for the precise customization of surgical interventions in the Peruvian population, especially in transsphenoidal surgery. The results highlight the importance of considering individual anatomical differences and gender variability during surgical planning. Morphometry emerges as a valuable tool to enhance the quality and safety of transsphenoidal surgery by adapting surgical strategies to the specific anatomical dimensions of each patient.

Surgical Navigation in the Anterior Skull Base Using 3-Dimensional Endoscopy and Surface Reconstruction

Importance

Image guidance is an important adjunct for endoscopic sinus and skull base surgery. However, current systems require bulky external tracking equipment, and their use can interrupt efficient surgical workflow.

Objective

To evaluate a trackerless surgical navigation system using 3-dimensional (3D) endoscopy and simultaneous localization and mapping (SLAM) algorithms in the anterior skull base.

Design, Setting, and Participants

This interventional deceased donor cohort study and retrospective clinical case study was conducted at a tertiary academic medical center with human deceased donor specimens and a patient with anterior skull base pathology.

Exposures

Participants underwent endoscopic endonasal transsphenoidal dissection and surface model reconstruction from stereoscopic video with registration to volumetric models segmented from computed tomography (CT) and magnetic resonance imaging.

Main Outcomes and Measures

To assess the fidelity of surface model reconstruction and accuracy of surgical navigation and surface-CT model coregistration, 3 metrics were calculated: reconstruction error, registration error, and localization error.

Results

In deceased donor models (n = 9), high-fidelity surface models of the posterior wall of the sphenoid sinus were reconstructed from stereoscopic video and coregistered to corresponding volumetric CT models. The mean (SD; range) reconstruction, registration, and localization errors were 0.60 (0.24; 0.36-0.93), 1.11 (0.49; 0.71-1.56) and 1.01 (0.17; 0.78-1.25) mm, respectively. In a clinical case study of a patient who underwent a 3D endoscopic endonasal transsphenoidal resection of a tubercular meningioma, a high-fidelity surface model of the posterior wall of the sphenoid was reconstructed from intraoperative stereoscopic video and coregistered to a volumetric preoperative fused CT magnetic resonance imaging model with a root-mean-square error of 1.38 mm.

Conclusions and Relevance

The results of this study suggest that SLAM algorithm-based endoscopic endonasal surgery navigation is a novel, accurate, and trackerless approach to surgical navigation that uses 3D endoscopy and SLAM-based algorithms in lieu of conventional optical or electromagnetic tracking. While multiple challenges remain before clinical readiness, a SLAM algorithm-based endoscopic endonasal surgery navigation system has the potential to improve surgical efficiency, economy of motion, and safety.

Computed tomography-based assessment of sphenoid sinus and sella turcica pneumatization analysis: a retrospective study

Background

A preoperative three-dimensional examination of the sphenoid sinus anatomy, its pneumatization pattern, and its relevance to neighboring neurovascular constructions is crucial to preventing possible complications. In this study, the aim was to evaluate the relationship between sphenoid sinus pneumatization types and the sella turcica using computed tomography (CT).

Methods

CT data from 420 patients referred to the Department of Dentomaxillofacial Radiology were evaluated retrospectively. Sella pneumatization types were classified as conchal, presellar, incomplete sellar, and complete sellar, and they were evaluated. Obtained data were evaluated using the IBM SPSS 25.0 (Armonk, New York, USA) package program.

Results

CT images of 420 individuals, including 174 women and 246 men with a mean age of 43.87 ± 17.58 years, were included in the study. When the sella turcica morphologies were evaluated, the most widespread morphological type was irregularity in the posterior part of the dorsum sella, in 51.2% of cases. In addition, a statistically significant correlation was found between the pneumatization of the sphenoid sinus and the morphological types of sella (p < 0.05).

Conclusion

In this research endeavor, the predominant observation comprised the complete sellar sphenoid sinus pneumatization type, exhibiting irregularity in the posterior aspect of the dorsum sella, representing one of the sellar types. Notwithstanding, it is imperative to conduct additional investigations to establish the generalizability of the present study's findings.

What to report in sellar tumor MRI? A nationwide survey among German pituitary surgeons, radiation oncologists, and endocrinologists

PURPOSE

While MRI has become the imaging modality of choice in the diagnosis of sellar tumors, no systematic attempt has yet been made to align radiological reporting of findings with the information needed by the various medical disciplines dealing with these patients. Therefore, we aimed to determine the prevailing preferences in this regard through a nationwide expert survey.

METHODS

First, an interdisciplinary literature-based catalog of potential reporting elements for sellar tumor MRI examinations was created. Subsequently, a web-based survey regarding the clinical relevance of these items was conducted among board certified members of the German Society of Neurosurgery, German Society of Radiation Oncology, and the Pituitary Working Group of the German Society of Endocrinology.

RESULTS

A total of 95 experts (40 neurosurgeons, 28 radiation oncologists, and 27 endocrinologists) completed the survey. The description of the exact tumor location, size, and involvement of the anatomic structures adjacent to the sella turcica (optic chiasm, cavernous sinus, and skull base), occlusive hydrocephalus, relationship to the pituitary gland and infundibulum, and certain structural characteristics of the mass (cyst formation, hemorrhage, and necrosis) was rated most important (> 75% agreement). In contrast, the characterization of anatomic features of the nasal cavity and sphenoid sinus as well as the findings of advanced MRI techniques (e.g., perfusion and diffusion imaging) was considered relevant by less than 50% of respondents.

CONCLUSION

To optimally address the information needs of the interdisciplinary treatment team, MRI reports of sellar masses should primarily focus on the accurate description of tumor location, size, internal structure, and involvement of adjacent anatomic compartments.

Pneumatization of the Greater Wing of Sphenoid Utilization for Lateral Wall Decompression

The goal of orbital decompression for thyroid orbitopathy is to expand the orbital space for the contents with various techniques described. Deep lateral wall decompression is a procedure that expands the orbit by removing bone from the greater wing of sphenoid however its effectiveness is dependent on the volume of bone removed. Pneumatization of the greater wing of sphenoid is defined as an extension of the sinus beyond the VR line (a straight line crossing the medial edges of the vidian canal and the foramen rotundum) which is a demarcation between the sphenoid body and the lateral parts of the sphenoid bone, including the greater wings and pterygoid process. We present a case of complete pneumatization of the greater wing of sphenoid affording a greater volume of bony decompression in a patient with significant proptosis and globe subluxation as a result of thyroid eye disease.

Neurovascular structures in the lateral recess of the sphenoid sinus. A computed tomography evaluation

INTRODUCTION AND OBJECTIVES

Anatomical variations of the lateral recess of the sphenoid sinus and its relations with the adjacent neurovascular structures should be preoperatively evaluated to plan an adequate surgical approach and avoid iatrogenic injuries. This study aims to analyze the patterns of pneumatization of the lateral recess of the sphenoid sinus and their association with the presence of protrusion and dehiscence of the optic canal, carotid canal, vidian canal, and maxillary nerve.

MATERIALS AND METHODS

A retrospective evaluation of 320 sphenoid sinuses by computed tomography was performed. Studied variables included type of lateral recess, and protrusion, and dehiscence of the optic and carotid canal, and vidian and maxillary nerve.

RESULTS

The mean age was 45.67±17.43. A total of 55.6% (n=178) of the evaluated sphenoid sinuses corresponded to male subjects. Protrusion of the carotid canal, maxillary nerve, and vidian canal was associated with a type 3 lateral recess pneumatization, while dehiscence of these structures was most commonly observed in a type 2 lateral recess (p=<0.001).

CONCLUSIONS

Protrusion or dehiscence of neurovascular structures surrounding the sphenoid sinus has been associated with the extent of pneumatization of the lateral recess, increasing the risk of intraoperative injury. Preoperative identification of anatomical variations is mandatory to select the best approach for skull base lesions and avoid iatrogenic injuries.

Preoperative Magnetic Resonance Imaging Localization of the Normal Pituitary Gland in Nonfunctioning Pituitary Adenoma Patients Using the Radiological Sign of "Internal Carotid Artery Notch"

OBJECTIVE

Asymmetric features of nonfunctioning pituitary adenoma (NFPA) are poorly understood. We investigated the asymmetry in NFPA on magnetic resonance imaging.

METHODS

We reviewed preoperative magnetic resonance imaging findings of patients initially treated for NFPA. The internal carotid artery (ICA) often seemed to cause an indentation in the external shape of the tumor (i.e., the ICA notch).

RESULTS

Two cases with a normal pituitary gland located at the midline were excluded. The remaining 66 cases were examined. The side where the normal gland was located was defined as the normal pituitary side and the opposite side as the cavernous sinus side. The Knosp grade was significantly higher on the cavernous sinus side (P < 0.001), and the vertical distance of the ICA was significantly greater on the cavernous sinus side (P < 0.001). The ICA notch was found in 87.9% of all cases on the normal pituitary side, but in only 45.5% on the cavernous sinus side (P < 0.001). In cases with a single-side ICA notch (34 of 68), the ICA notch was found in 91.2% of cases and on the cavernous sinus side in 8.8% (P < 0.001).

CONCLUSIONS

Magnetic resonance imaging of NFPA frequently shows asymmetry. The tumor does not extend laterally on the normal pituitary side but extends laterally more freely on the cavernous sinus side. The ICA notch is often found on the normal pituitary side where the position of ICA does not move. This may be useful as a preoperative sign to indicate the normal pituitary side.

Relationships of sphenoid sinus pneumatization with internal carotid artery characteristics

Objective

We explored the clinical significances of the relationships among sphenoid sinus aeration, intersphenoid sinus septum (ISS), and internal carotid artery (ICA).

Methods

We retrospectively reviewed the preoperative paranasal sinus computed tomography scans and the medical charts of 490 patients who were treated by the endoscopic endonasal transsphenoidal approach. We analyzed sphenoid sinus pneumatization, number of ISS, and positional relationships between the ICA and ISS (including ICA prominence and the thickness of surrounding bone).

Results

ISS were often present in the ICAs of patients with presellar pneumatization (36.2%; p = 0.042). Sphenoid sinus pneumatization status significantly differed according to number of ISS (p < 0.001), ICA prominence (p < 0.001), ISS insertion into the ICA (p = 0.042), and distance from ISS to ICA (p = 0.004). When sphenoid sinus aeration was poor, the ICA was not prominent, and the ISS were attached to or lay close to the paraclival ICA.

Conclusions

Patients with presellar pneumatization exhibited less prominent ICAs, and more ISS attached to or near the paraclival ICA, than did other patients. Therefore, particular caution is required when using the endoscopic endonasal transsphenoidal approach to treat patients with poor sphenoid sinus aeration.

The Role of Endonasal Endoscopic Skull Base Repair in Posttraumatic Tension Pneumocephalus

OBJECTIVES

Information about the endonasal endoscopic approach (EEA) for the management of posttraumatic tension pneumocephalus (PTTP) remains scarce. Concomitant rhinoliquorrhea and posttraumatic hydrocephalus (PTH) can complicate the clinical course.

METHODS

The authors systematically reviewed pertinent articles published between 1961 and December 2020 and identified 6 patients with PTTP treated by EEA in 5 reports. Additionally, the authors share their institutional experience including a seventh patient, where an EEA resolved a recurrent PTTP without rhinoliquorrhea.

RESULTS

Seven PTTP cases in which EEA was used as part of the treatment regime were included in this review. All cases presented with a defect in the anterior skull base, and 3 of them had concomitant rhinoliquorrhea. A transcranial approach was performed in 6/7 cases before EEA was considered to treat PTTP. In 4/7 cases, the PTTP resolved after the first intent; in 2/7 cases a second repair was necessary because of recurrent PTTP, 1 with and 1 without rhinoliquorrhea, and 1/7 case because of recurrent rhinoliquorrhea only. Overall, PTTP treated by EEA resolved with a mean radiological resolution time of 69 days (range 23-150 days), with no late recurrences. Only 1 patient developed a cerebrospinal fluid diversion infection probably related to a first incomplete EEA skull base defects repair. A permanent cerebrospinal fluid diversion was necessary in 3/7 cases.

CONCLUSIONS

Endonasal endoscopic approach repair of air conduits is a safe and efficacious second-line approach after failed transcranial approaches for symptomatic PTTP. However, the strength of recommendation for EEA remains low until further evidence is presented.

Sellar Region Lesions and Intracranial Aneurysms in the Era of Endoscopic Endonasal Approach

In the clinical practice of neurosurgery, the endoscopic endonasal approach (EEA) has been the mainstream approach in the management of sellar region diseases. However, clinicians have come to realize that EEA procedure is associated with intraoperative hemorrhage. Due to the limited surgical field and poor proximal control under endoscope, massive hemorrhage always leads to severe complication or even perioperative death. Previously, intraoperative hemorrhage used to be attributed to endoscopic intervention of cavernous sinus or internal carotid artery, but our recent understanding of EEA indicated that preoperatively complicated intracranial aneurysms (IAs) may play a role. In this article, we retrospectively reviewed the baseline characteristics, treatment strategy, pathology, intraoperative findings, as well as radiological profiles of sellar region lesions complicated with IAs. With the focus put on the high comorbidity rate of sellar region lesions and IAs, we did further statistical analysis to sketch the outline of this coexisting circumstance and to emphasize the importance of computed tomography angiography (CTA) as routine EEA preoperative examination. Thorough patient-surgeon communication should be proceeded before the formulation of an individualized treatment strategy.

Neuroimaging of central diabetes insipidus

Central diabetes insipidus (CDI) occurs secondary to deficient synthesis or secretion of arginine vasopressin peptide from the hypothalamo-neurohypophyseal system (HNS). It is characterized by polydipsia and polyuria (urine output >30mL/kg/day in adults and >2l/m²/24h in children) of dilute urine (<250mOsm/L). It can result from any pathology affecting one or more components of the HNS including the hypothalamic osmoreceptors, supraoptic or paraventricular nuclei, and median eminence of the hypothalamus, infundibulum, stalk or the posterior pituitary gland. MRI is the imaging modality of choice for evaluation of the hypothalamic-pituitary axis (HPA), and a dedicated pituitary or sella protocol is essential. CT can provide complimentary diagnostic information and is also of value when MRI is contraindicated. The most common causes are benign or malignant neoplasia of the HPA (25%), surgery (20%), and head trauma (16%). No cause is identified in up to 30% of cases, classified as idiopathic CDI. Knowledge of the anatomy and physiology of the HNS is crucial when evaluating a patient with CDI. Establishing the etiology of CDI with MRI in combination with clinical and biochemical assessment facilitates appropriate targeted treatment. This chapter illustrates the wide variety of causes and imaging correlates of CDI on neuroimaging, discusses the optimal imaging protocols, and revises the detailed neuroanatomy required to interpret these studies.

Preoperative Computed Tomography Imaging of the Sphenoid Sinus: Striving Towards Safe Transsphenoidal Surgery

Introduction  Preoperative high-resolution computed tomography (HRCT) is essential in patients undergoing transsphenoidal surgery to identify potential high-risk anatomic variations. There is no consensus in the literature, as to which grading system to use to describe these variants, leading to inconsistent terminology between studies. In addition, substantial variability exists in the reported incidence of anatomic variants. In this study, we performed an institutional imaging analysis and literature review with the objective of consolidating and clearly defining these sphenoid sinus anatomical variations. In addition, we highlighted their surgical implications and propose a checklist for a systematic assessment of the sphenoid sinus on preoperative CT. Methods  Review of the literature and retrospective analysis assessing several imaging parameters in 81 patients who underwent preoperative HRCT imaging for endoscopic transsphenoidal tumor resection from January 2008 through July 2015 at Rush University Medical Center. Results  The most common sphenoid pneumatization patterns were sellar (45%) and postsellar (49%) types. Anterior clinoid process (ACP) pneumatization was seen in 17% of patients with high concordance of ipsilateral optic nerve (ON) protrusion. ON protrusion and dehiscence was present in 17 and 6% of patients, respectively. Internal carotid artery (ICA) protrusion and dehiscence was present in 30 and 5% of patients, respectively. Dehiscence rates from local bone invasion overlying the ICA and ON occurred in 17 and 4% of cases, respectively. Conclusions  Our study highlights and reviews the key variants that have potential to impact surgical complications and outcomes in a heterogeneous patient population. The proposed preoperative CT checklist for patients, undergoing transsphenoidal surgery, consistently identifies these higher risk anatomical variants.

Transnasal Transsphenoidal Approach for Pituitary Tumors: An ENT Perspective

Endoscopic transnasal transsphenoidal (ETNTS) approach was first described in 1992 and is standard approach for the resection of benign pituitary adenomas. This prospective study aims in incidence and preoperative assessment of extent of the pituitary adenoma, peroperative findings of transnasal transsphenoidal excision, techniques of skull base repair, complications and its management in a tertiary centre. A prospective analysis from Jan 2017 to May 2019, of patients undergoing ETNTS approach of pituitary adenomas was made in terms of incidence in various age-groups, type of adenoma, operative findings including CSF leak, repair of the skull base defect, complications encountered and its management was done in a tertiary care centre and compared with the present literature. A total of 141 patients underwent ETNTS, with highest number of cases found in 41-50 years age-group with mean age of 42.6 years. Male: Female ratio was 1.6. Macroadenoma was in 123 patients while 18 had microadenoma, of these 63.74% were functional adenoma, highest of GH secreting, while 36.26% were non-functional. Mean surgical time was 98.4 min ± 21.2 min. Peroperative CSF leak was in 30.5% cases in various grades. Closure techniques included use of fat, multilayer techniques, Hadad's flap and gasket technique as per the type of CSF leak. Neurological and rhinological complications were 6.38% each. This study is focused on the ENT perspective of the endoscopic transnasal trans-sphenoidal approach for pituitary adenomas. The reduced rate of morbidity and complications is encouraging. The endoscopic skull base defect closure is challenging and requires skill, meticulous approach and synchronised team work in order to achieve a favourable outcome. The incidence of CSF leak can be minimised and if encountered has to be dealt in an organised manner, thus contributing to a reduced rate of complications. The complications encountered must be foreseen and managed with a proficient approach.

Perioperative nasal and paranasal sinus considerations in transsphenoidal surgery for pituitary disease

Endoscopic endonasal skull base surgery has emerged as the treatment modality of choice for a range of skull base lesions, particularly pituitary adenomas. However, navigation and manipulation of the nasal corridor and paranasal sinuses requires that surgeons are aware of effective techniques to maximize patient outcomes and avoid sinonasal morbidity postoperatively. This paper is a narrative review aimed to provide an updated and consolidated report on the perioperative management of the nasal corridor and paranasal sinuses in the setting of endoscopic skull base surgery for pituitary disease. Anatomic variants and common surgical techniques are discussed. Post-operative complications are evaluated in detail. Understanding the structural implications of the endonasal approach to the sphenoid is crucial to optimization of the surgical outcomes. We propose guidelines for perioperative management of endoscopic endonasal skull base surgery for pituitary diseases. Standardized treatment algorithms can improve patient satisfaction, and increase the comparability and the quality of reported information across research studies.

Anatomical Workspace Study of Endonasal Endoscopic Transsphenoidal Approach

Purpose

To determine the workspace through an anatomical dimensional study of the skull base to further facilitate the design of the robot for endonasal endoscopic transsphenoidal (EET) surgery.

Methods

There were 120 cases having a paranasal sinus CT scan in the database. The internal volumes of the nasal cavities (NC), the volumes of the sphenoid sinuses (SS), and the distance between the anterior nasal spine and base of the sellar (d-ANS-BS) were measured.

Results

The Pearson correlation coefficient (PCC) between the relevant distances and the volumes of the right NC was 0.32; between the relevant distances and the volumes of the left NC was 0.43; and between the relevant distances and volumes of NC was 0.41; with a statistically significant difference (p < 0.001). All PCCs had a statistically significant meaningful difference (p < 0.05).

Conclusion

The volume of NCs were significantly correlated with distances (p < 0.05). The safest and shortest distance to guide the robotic arm length in the EET approach could be represented by d-ANS-BS. This result was also used as primary information for further robotic design.

Endoscopic transsphenoidal approach to skull base lesions. A clinical prospective study

OBJECTIVE

To review the patients operated by endoscopic transphenoidal approach for skull base lesions. All the clinical data including age, gender, type of pathology, surgical outcome and surgical complications were studied.

METHODS

A clinical prospective study was conducted on 94 cases with skull base lesion that were treated in Neuroscience Hospital in Baghdad, Iraq between October 2011 and December 2016. We followed each patient for an average of 2 years after surgery to determine most common lesion involving the skull base, age and gender distribution, surgical outcome, complications and hospital accommodation. Freeze system of Storz all the cases in the study.

RESULTS

The majority of our patients were between the ages of 20-29 years. Among the 94 patients, 67% had macro adenomas, followed by craniopharyngioma 11%. The mortality rate was 2.1%, Gross total removal was 57.4%. All patients show improvement of the headache after surgery, visual improvement was noticed in 73.4% and hospital accommodation was 2-5 days. Three patients developed cerebrospinal fluid leak, Infection meningitis developed in 3 patients 3.1%, and 2 patients (2.1%) suffered from hormonal disorders and were referred to endocrinologist for therapy. Diabetes insipidus developed as a temporary complication in 4 cases (4.2%).

CONCLUSION

Trassphenoidal surgery is relatively safe surgery for properly selected patients.

Surgical Robotic Technology for Developing an Endonasal Endoscopic Transsphenoidal Surgery (EETS) Robotic System

Purpose:

Neurosurgical robots are acknowledged for their advantages in assisting neurosurgeons in enhancing their precision and accuracy. Here, the aim of this study is to report the first use as a robot-assisted Endonasal Endoscopic Transsphenoidal (EET) approach, applied to reach sphenoid sinus in a cadaver. The introduction of the seven tenets for the Endonasal Endoscopic Transsphenoidal approach will propel the feasibility of neurosurgical techniques and instruments for intrasellar lesions.

Methods:

Endonasal endoscopic transsphenoidal approach in a cadaver was performed under robot assistance with simple navigation system. This preliminary study reveals the accuracy and precision of the robot to reach a target at sphenoid sinus safely and within the shortest duration .

Results:

This robotic technology provided the foundation to support neurosurgeons when they are working in narrow and complicated surgical corridors with accuracy and precision.

Conclusion:

This article reveals the first robot-assisted Endonasal Endoscopic Transsphenoidal approach. This demonstrates the feasibility of the evolution and will augment neurosurgeons toward their limits of minimally invasive surgical techniques, manual dexterity, and spatial orientation. These tenets will be as state of the art and overcome the future challenges of Endonasal Endoscopic Transsphenoidal approach shortly.

Analysis of Endonasal Endoscopic Transsphenoidal (EET) surgery pathway and workspace for path guiding robot design

BACKGROUND

Endoscopic Endonasal Transsphenoidal Surgery (EETS) is the standard method to treat pituitary adenoma, tumor in the pituitary gland which would affect human beings in terms of hormonal malfunction and other symptoms. This procedure provides extra minimal invasive access in severe cases. The objective of this paper is to design and develop a prototype of EET robot with navigation guidance system based on the study of EET workspace and pathway to determine a safe space for surgical tool insertion.

METHODS

The EET workspace and its pathway were studied via data collected from EET experiments on 70 cadavers. An optical tracking system was used to detect and record the movement of the surgical tools during the experiments. Delaunay triangulation and Voronoi diagram were utilized to determine the cloud position of the gathered data for EET workspace. Moreover, in order to determine the EET pathway voxelization methods were incorporated.

RESULTS

The average diameter of the workspace calculated was 19.08 with 3.32 S. D, the average length and volume of the workspace were 53.9 mm and 15.9cm3, respectively. The S.D values determined for length and volume were 7.2 and 6.02, respectively. For the pathway, a high density area was determined via data obtained through cloud position.

CONCLUSION

Dimension of the EET workspace and characters of EET pathway determine robot's requirements to design and develop EET robotic system. This article demonstrates the conceptual design of an EET robot and successfully accomplishes the goal of guidance and aids in assisting the EET procedures.

Neurosurgical complications: what the radiologist needs to know

Visits to the emergency department by patients who have recently undergone neurosurgery are a common occurrence, and these patients frequently receive emergent cross-sectional head imaging in order to evaluate for complications. Different neurosurgical approaches may have typical postoperative imaging findings that can be confused with pathology. Furthermore, particular abnormal postoperative imaging findings may signal an evolving complication. It is essential for the radiologist to understand common neurosurgical procedures and their potential complications in order to provide proper diagnostic evaluation of the postoperative neurosurgical patient. The purpose of this review is to assist radiologists in the evaluation of the postoperative neurosurgical patient and educate them on associated complications. Familiarity with common neurosurgical techniques and postoperative complications will help radiologists make the correct diagnosis, communicate effectively with the neurosurgeon, and expedite patient care.

Utilization of the Nasoseptal Flap for Repair of Cerebrospinal Fluid Leak after Endoscopic Endonasal Approach for Resection of Pituitary Tumors

Background

One of the most frequent complications after endoscopic endonasal approach (EEA) for resection of pituitary tumors is cerebrospinal fluid (CSF) leaks. With the introduction of the pedicled nasoseptal flap, the reconstruction of the skull base has improved significantly resulting in a decrease in the occurrence of persistent CSF leaks. We present our experience utilizing the pedicled nasoseptal flap technique after EEA for reconstruction of the skull base in cases where CSF leak was detected.

Methods

Data for patients undergoing EEA for pituitary tumors was retrospectively reviewed. These included demographic, clinical, operative, radiographic, and pathological information. Incidence of post-operative complications and CSF leaks were recorded. Descriptive statistical analysis was performed.

Results

Between 2008 and 2015, 67 patients and 69 hospital admissions with pituitary tumors underwent a nasoseptal flap to reconstruct a skull base defect at Johns Hopkins Hospital. The mean age at surgery was 54.5±14.2 years. Fifty-two percent of patients were male. Forty-six percent of patients were white, 33% African-American, and 12% belonged to other racial groups. There was an intraoperative CSF leak in 39% of patients. Seventy percent of patients with an intraoperative CSF leak had a nasoseptal flap reconstruction of the skull base. There were zero postoperative CSF leaks.

Conclusion

With the introduction of the pedicled nasoseptal flap for reconstruction of the skull base after EEA for resection of pituitary adenomas, the incidence of postoperative CSF leaks has decreased significantly. In this retrospective analysis, we demonstrate the effectiveness of the use of nasoseptal flap in repairing CSF leak after EEA.

Radiological "Teddy Bear" Sign on CT Imaging to Aid Internal Carotid Artery Localization in Transsphenoidal Pituitary and Anterior Skull Base Surgery

Objectives  Internal carotid artery (ICA) injury remains a rare but potentially fatal complication of transsphenoidal pituitary or anterior skull base surgery. Preoperative imaging must be scrutinized to minimize risk. On axial computed tomography (CT), the protrusions of the ICAs into the sphenoid resemble a "teddy bear." This article aims to describe the sign, its grading system (0-2) and quantify its presence. Design  Retrospective review of preoperative CT imaging. Setting  Tertiary referral center in the United Kingdom. Participants  One hundred patients who underwent endoscopic transsphenoidal surgery for pituitary disease were enrolled. Main Outcome Measure  The presence and grading of the "teddy bear" sign were assessed on preoperative CT imaging. Results  A grade 2 (strongly positive) "teddy bear" sign was identified in 40% at the level of the superior pituitary fossa, 78% at the inferior pituitary fossa, and 59% at the clivus. A grade 1 (intermediate) sign was seen in 23.5, 7.5, and 10% of cases, respectively. In 5% of cases, the sign was grade 0 at all levels-indicating poor intraoperative localization of the ICA. Conclusion  The "teddy bear" sign is a useful preoperative tool for identification of anatomy predisposing patients to a higher risk of ICA injury. Those patients who have an absent or grade 0 "teddy bear" sign require extra care to ensure intraoperative localization of the ICAs which may include the use of neuronavigation or a Doppler probe. A grade 2 sign predicts good intraoperative localization of the ICA intraoperatively to inform the safe lateral limit of sellar bone resection.

Cerebrospinal fluid rhinorrhea and otorrhea: A multimodality imaging approach

Cerebrospinal fluid (CSF) leaks are extracranial egress of CSF into the adjacent paranasal sinus or tympanomastoid cavity due to an osteodural defect involving skull base. It can be due to a multitude of causes including accidental or iatrogenic trauma, congenital malformations and spontaneous leaks. Accurate localization of the site of the leak, underlying causes and appropriate therapy is necessary to avoid associated complications. In this paper relevant anatomy, clinical diagnosis, imaging modalities and associated findings are discussed along with a brief mention about management.

Magnetic resonance imaging of sellar and juxtasellar abnormalities: atypical findings of common diseases and typical findings of rare diseases

The sellar/juxtasellar region comprises the bone component of the sella turcica, pituitary gland, cavernous sinus, and suprasellar cistern. Abnormalities in this region can be attributed to underproduction or overproduction of hormones or to the neurological signs and symptoms resulting from the compression of adjacent structures. Magnetic resonance imaging (MRI) is currently the imaging method of choice, having supplanted computed tomography. The aim of this study was to demonstrate the common and uncommon imaging aspects of sellar and juxtasellar changes, which could facilitate the differential diagnosis. We retrospectively evaluated the MRI scans of 70 patients with sellar/juxtasellar abnormalities from didactic files, and report those with more unusual changes, where MRI played an important role in diagnosis. All cases were confirmed histologically or clinical laboratory.

Extent of Surgery in Endoscopic Transsphenoidal Skull Base Approaches and the Effects on Sinonasal Morbidity

Background

Endoscopic transsphenoidal skull base surgery (ETSS) is now considered the criterion standard approach for resection of pituitary adenomas and other midline anterior skull base lesions. Normal sinonasal structures are resected during ETSS, which raises concerns for nasal morbidity and patient-based outcome.

Objective

To perform a surgical outcome assessment by examining whether the extent of ETSS approaches affected patient-specific sinonasal quality of life as measured by the 22-item Sino-Nasal Outcome Test (SNOT-22).

Methods

A single-center prospective cohort study of patients operated on by the same skull base team between 2012 and 2016. Patients with completed pre- and postoperative SNOT-22 were included. The primary outcome was SNOT-22 scores at preoperative, 0–1 month, 2–4 months, >5 months follow-up. Age, sex, tumor pathology, surgical procedure, and intraoperative cerebral spinal fluid leak repair were also obtained.

Results

Of the 249 ETSS performed, 148 patients (59%) had at least one completed SNOT-22; 45 (18%) met the inclusion criteria. Sinonasal quality of life based on SNOT-22 at the 0–1-month follow-up was significantly worse than the presurgical levels (p < 0.05). However, there was a return of SNOT-22 scores to preoperative levels at 2–4 months (p > 0.05), which was sustained at >5 months (p > 0.05). Factors such as the extent of ETSS, a previous nasal surgery, repair of an intraoperative cerebral spinal fluid leak, and the tumor pathology did not affect SNOT-22 scores at any follow-up intervals (p > 0.05).

Conclusion

Sinonasal quality of life worsened after ETSS at 0–1 month follow-up but returned to preoperative levels at 2–4 months and remained at postoperative levels >5 months. Analysis of these data will allow us to educate our patients that the anticipated nasal morbidity after ETSS is usually only transient and should be expected to recover to preoperative levels.

Sphenoid Sinus Pneumatization, Septation, and the Internal Carotid Artery: A Computed Tomography Study

Background:

The air spaces of the nasal cavity and the sphenoid sinus (SS) constitute a convenient corridor to access lesions of the skull base using the endoscopic endonasal transsphenoidal approach (EETA). Safe EETA depends on the SS and skull base anatomy of the patient. Individual variations exist in the degree and pattern of SS pneumatization. This study aims to examine the variations in SS pneumatization, the inter-sphenoid septum (ISS), and their relationship with the internal carotid artery (ICA) among adult Nigerians.

Materials and Methods:

We reviewed computerized tomography (CT) images of 320 adult patients that had imaging for various indications. This excluded those with traumatic, inflammatory, or neoplastic process that may alter anatomical landmarks. The images were evaluated for the types of SS pneumatization, number and insertion of ISS, and the protrusion of ICA into the sinus cavity.

Results:

Prevalence of SS pneumatization types: 1.9% conchal, 1.2% presellar, 56.6% sellar, and 40.2% postsellar. The lateral extension of SS occurred into the pterygoid in 138 patients (45.1%), greater wing 112 (35%), lesser wing 37 (11.6%), the full lateral type was seen in 97 (30.3%) patients. One ISS occurred in 150 (46.9%) patients, 162 (50.6%) had multiple, and 8 (2.5%) had none. ISS insertion into ICA bony covering occurred in 101 (31.6%) patients, whereas protrusion of ICA into SS cavity occurred in 110 (34.4%) patients.

Conclusion:

Variations of the SS, ISS, and ICA anatomy are present among native Africans. Detailed imaging evaluation of each patient is considered for EETA is mandatory.

Combined External-Endoscopic Endonasal Assisted Removal of a Nail Gun

Management of penetrating trauma to the paranasal sinuses with retained foreign bodies represents a challenge due to the proximity to vital neurovascular structures. The authors report the successful treatment of a patient with a work-related nail gun injury, carried out by means of a combined endoscopic endonasal external assisted procedure.A transnasal endoscopic approach was planned to minimize inadvertent movements of the nail during surgery and in case necessary to repair the orbit or skull base. No major bleeding or neurovascular complication was observed after surgery and a computed tomography scan was performed after surgery confirming the complete removal of the nail and with no damage of the orbit nor the skull base.

Imaging of Paranasal Sinuses and Anterior Skull Base and Relevant Anatomic Variations

This article reviews the normal anatomy and variants of the anterior skull base and sinonasal cavities that are relevant to endoscopic sinus and skull base surgery. Radiologists should be aware of sinonasal anatomy that can be impediments to surgical access and increase risk of vascular or cranial nerve injury during surgery. Imaging features of the paranasal sinuses and anterior skull base pathologies are also discussed.