Endoscopic Skull Base Approaches Research Articles

Combined Endonasal and Transseptal Approach to Achieve Binostril Access in Endoscopic Skull Base Approaches to Minimize Nasal Morbidity: A Technical Note

IntroductionOver the years, feasibility & safety of EEAs has become well established & the focus has now shifted to minimising the nasal morbidity. To this end, several modifications in nasal stage have been described that have focussed primarily on preservation of nasal mucosa on right side of nasal cavity (NC). However, the issue of nasal mucosal preservation on left side of NC has largely been ignored. In this paper, the author describes a modified technique that can eliminate mucosal damage in left NC. MethodIn modified technique, trans-septal approach is utilised on left & endonasal on right side. A hemitransfixion incision is used to raise left submucosal tunnel. The mucosa of tunnel lies laterally in apposition with lateral nasal wall, thereby protecting it from injury by repeated passage of instruments. When tunnel mucosa is pushed back medially, left NC appears absolutely normal without any evidence of mucosal damage. ResultsCombined endonasal & trans-septal technique for nasal stage was performed in 51 patients with sellar/suprasellar lesions. Nonfunctional pituitary adenomas were the most common pathology (macroadenomas-n=14; Giant adenomas-n=10) followed by functional adenomas (acromegaly-n=10; prolactinomas- n=3; Cushings’s disease- n=1), craniopharyngiomas (n=6), clival tumours (n=5), & tuberculum sella meningiomas (n=2). ConclusionsA combination of endonasal and trans-septal approaches utilises the advantages of both endoscopic & microscopic approaches sans the disadvantage of restricted space seen in microscopic approaches. It makes binostril approach least disruptive to left nasal mucosa & thus can reduce overall morbidity of EEAs.

The lateral based nasopharyngeal flap: A novel vascularized flap for skull base reconstruction.

As the indications for endoscopic skull base approaches have increased, so has the need for more versatile vascularized flaps for skull base reconstruction. Here, we describe a novel lateral based nasopharyngeal flap (LNPF). Two cadaver heads were dissected to elucidate flap anatomy, dimensions, and technique. A retrospective review was performed on two cases where LNPF was used to repair CSF leaks in the nasopharyngeal area, and outcomes reported. The LNPF is an ascending pharyngeal artery myomucosal flap that includes the nasopharyngeal mucosa and the superior pharyngeal constrictor muscle. The flap was 1.2 × 2.2 cm in greatest dimensions. The LNPF was used for salvage CSF leak repair in two cases: one clival and one tubal. Both patients had resolution of leak at 7 months follow-up. The LNPF is a novel flap with reconstruction potential for the nasopharynx, including the lower clivus and the eustachian tube.

Development and Validation of a Novel Human-Fixed Cadaveric Model Reproducing Cerebrospinal Fluid Circulation for Simulation of Endoscopic Endonasal Skull Base Surgery.

Endoscopic endonasal surgery is a well-established surgical approach to the skull base. Surgeons need a reusable long-lasting tool to acquire the skills needed for skull base reconstruction. The aim of this study was to elaborate and validate a human formalin-fixed cadaveric model that reproduces a realistic cerebrospinal fluid (CSF) circulation and that adequately renders a CSF leak. An external ventricular drain that connects with a peristaltic pump is placed in the subarachnoid space, which allows a water circulation that reproduces CSF circulation. Intracranial pressure is measured in real time. Endoscopic endonasal skull base approaches are performed, to create different skull base openings and CSF leaks. Participants were tasked with reconstruction of the defects using a standardized multilayered approach, with the goal of obtaining a watertight closure under normal intracranial pressure ranges. Compiled data included time of reconstruction, years of experience of participants, and success/failure to achieve a watertight reconstruction. A Likert questionnaire was also used. The cadaveric model reproduced CSF circulation in 4 types of dural defects: sellar, suprasellar, transcribriform, and transclival. Intracranial pressures were similar to physiological conditions and were reproducible. Each model was tested multiple times, over several months. Success rates concurred with training levels (r = .8282 and P = .0017). A strong inverse correlation was also found between years of experience and time of reconstruction (r = .4977 and P < .0001). Participants agreed that the model was realistic (median Likert score of 4), and they strongly agreed that it allowed for the improvement of their surgical skills (median Likert score of 5). This novel human-fixed cadaveric model for CSF circulation is efficient and adequately reproduces surgical conditions for skull base approaches. The model is unique, easy to reproduce, and reusable. It can be used as a tool for teaching and for research purposes.

Effect of endoscopic endonasal skull base approaches on olfactory function and facial development in children.

Endoscopic approaches for skull base pathologies are increasingly being performed, and the subsequent complications, especially in the long term, have also been partially clarified. However, there is no information on the effects of endoscopic endonasal skull base surgeries (EESBS) in children on odor and facial development in parallel with long-term development. We conducted this study to investigate postoperative olfactory function and facial development in pediatric patients who underwent skull base surgery using the endoscopic endonasal method. We evaluated the smell test, sinonasal symptoms, and facial development of pediatric patients who underwent endoscopic endonasal skull base surgery after long-term follow-up. Odor was evaluated using the "Sniffin' Sticks" test kit, which assessed the T (odor threshold), D (odor discrimination), and I (odor identification) parameters. Sinonasal symptoms were evaluated using the SNOT-22 (sinus-nose outcome test) questionnaire. SNA (sella-nasion-A point), SNB (sella-nasion-B point), and ANB (A point-nasion-B point) angles were calculated from maxillofacial tomography and magnetic resonance imaging) to evaluate facial development. Data were compared with those of the healthy control group. We included 30 patients comprising 19 (63.3%) boys and 11 (36.7%) girls, with no age difference between case and control groups.The mean follow-up period was 7 years. Odor test data, cephalometric measurements, and SNOT-22 analysis results showed no statistically significant differences between the two groups. To our knowledge, this is a comprehensive study with the longest follow-up period in terms of evaluation of facial development after EESBS in children to analyze odor using the Sniffin' Sticks test kit and the quality of life using SNOT-22. Olfactory function, facial development, and quality of life remained unaffected after long-term follow-up after EESBS in children. Although this surgical approach is minimally invasive, we recommend considering the possibility of complications, and the procedure should be performed by an experienced surgical team with adequate equipment.

Paediatric endoscopic endonasal middle skull base reconstruction: retrospective analysis of 78 patients treated in a single tertiary care paediatric center

Introduction Skull base pathologies in the paediatric population are rare and require treatment by multiple qualified specialists. The endoscopic endonasal approach has revolutionized surgical treatment because it is less invasive than existing treatments.The goal of this study was to retrospectively review our experience with the reconstruction of paediatric skull middle base defects and associated complications. Materials and methods We analysed medical records from patients aged ≤ 18 years who were treated at our centre between 2013 and 2021. Patients treated with an endoscopic skull base approach and reconstruction, and who had complete clinical and radiological documentation and a minimum follow-up of 12 months, were included in the analysis. Personal data, reconstructive techniques, and complications were analysed. Results A total of 78 patients met the inclusion criteria and were enrolled in the study. Of these patients, 32 were male and 46 were female, and the mean age was 11.5 years. The main signs and symptoms were as follows: bitemporal hemianopsia in 53 cases, visual impairment in 23 cases, and headache in 30 cases. The most frequent aetiologies were craniopharyngioma (38 cases), pituitary adenoma (23 cases), and clivus chordoma (4 cases). All patients were treated via a pure endoscopic approach. For reconstruction, a multilayer technique was used in 18 cases, naso-septal flap in 43 cases, Gasket-Seal technique in 12 cases, and heterologous reconstruction in 5 cases. Only six patients presented a major complication: two had a postoperative cerebral spinal fluid leak, one developed a brain abscess, and three had diabetes insipidus.The mean follow-up period was 23.4 months.There were no statistically significant differences in postoperative CSF leak in relation to different reconstructive techniques. Conclusion Endoscopic endonasal skull base surgery is a safe and effective treatment for paediatric middle skull base pathologies. Reconstruction techniques have a high success rate of 96.5–100%, and the rate of associated complications is < 3%.

A computed tomography (CT)-based morphometric study of various skull base parameters and their anatomical relationships relevant to endoscopic endonasal skull base surgery.

Endoscopic skull base surgery requires a thorough understanding of skull base anatomy. Orientation to regional anatomy to avoid complications like internal carotid artery injury can be assisted by knowledge of certain bony landmarks. These landmarks are themselves highly variable structures. This study focuses on the radiological morphometric characterization of these landmarks, which can be of great assistance to surgeons for better planning of endoscopic skull base approaches. Computed tomography scans of patients without skull base pathologies were analyzed retrospectively for the following parameters - Vidian canal (VC) length, VC and foramen rotundum (FR) distance from midline, the angle between the axis of VC and petrous internal carotid artery (pICA) and between VC and palatovaginal canal, the horizontal, vertical and direct distances between VC and FR and the patterns of sphenoid sinus (SS) pneumatization. The VC-pICA angle was more obtuse and VC and FR were placed farther off the midline on the left as compared to the right side. Similarly, the distances between VC and FR were more on the left side. The VC length and distance of VC and FR from the midline were longer in males than in females. The VC-pICA angle was more obtuse in females. The post-sellar variant was the predominant pneumatization pattern seen (57.9%), and the incidence of lateral recess pneumatization was 15%. The results of our study can be utilized for a better understanding of the anatomy of the skull base. In skull base pathologies with distorted anatomical landmarks, a basic understanding of their interrelations can be used to have a better anatomical orientation. All these measures can help in avoiding complications and make extended endoscopic approaches safe.

Microsurgical Resection of a Thalamic Tumor Using an Endoscopic Contralateral Supracerebellar Infratentorial Keyhole Approach: 2-Dimensional Operative Video.

The surgical treatment of the thalamic lesions is one of the most technically challenging interventions because of their deep-seated location and the proximity of the surrounding vital neurovascular structures: thalamic nuclei, limbic system components, visual and oculomotricity pathways, deep cerebral veins, and posterior cerebral artery branches.1 Traditional microsurgical approaches for these lesions usually require large open craniotomies and further retraction or resection of neural tissue to facilitate better visualization, associating significant postoperative morbidity or even mortality. The recent improvements in high-resolution fiber optics technology have allowed neurosurgeons to expand their surgical armamentarium for tackling these difficult-to-reach lesions. The patient consented to the procedure, and in this surgical video, we try to emphasize the advantages of an endoscopic supracerebellar infratentorial approach over the classic microsurgical approach, along with the keyhole craniotomy and the sitting positioning of the patient. The endoscope provides better visualization-dynamic in-depth view of the anatomic and pathological structures, angled-optics help the surgeon to see "around-the-corner," and the entire procedure is a more comfortable experience for the surgeon and also for the patient, using the minimally invasive techniques. Moreover, we underline the need for a strong collaboration with an experienced endoscopic surgeon (for eg, ear, nose and throat surgeon), as for other endoscopic skull base approaches. The participants and any identifiable individuals consented to publication of his/her image.

Classification of Endoscopic Transnasal Lateral Skull Base Approaches: Anatomical Study

Endoscopic transnasal approaches (ETAs) to the ventrolateral skull base are commonly classified according to coronal planes or anatomical structures. Our goal is to simplify the description of the ETA to lateral skull base regions in a sequential dissection with correlation to computed tomography, helping in preoperative planning and efficient surgical exposure, and exposing the surgical anatomy limitations. Five freshly injected cadaver heads were dissected using an extended ETA to the lateral skull base. Each specimen underwent a high-resolution computed tomography scan. A classification of the lateral skull base based on well-defined zones was proposed. We divided the lateral target into four different zones, in a craniocaudal orientation: zone 1 is the space lying between the orbital floor superior and the level of the sellar floor inferior, zone 2 is on the coronal plane, located between the level of the sellar floor and the vidian canal, zone 3 is the area lateral to the anterior limb of the petro-occipital fissure, located between the vidian canal and the carotid canal, and zone 4 is the space located between the carotid canal and the extracranial opening of the hypoglossal canal, lateral to the anterior part of the posterior limb of petro-occipital fissure. Multiple previous works have described and classified the coronal plane and its lateral extensions. Our classification system for the proposed lateral zones enables preoperative planning to select a suitable approach. The craniocaudal orientation facilitates the understanding of surgical corridors and tailored exposure.

Advances in Pituitary Surgery.

Pituitary surgery has advanced considerably in recent years with the exploration and development of various endoscopic approaches and techniques. Different endoscopic skull base approaches are being applied to access sellar tumors in different locations. Moreover, extracapsular dissection and cavernous sinus exploration have enabled gross total resection of sellar tumors where it could not have been achieved in the past. Techniques for skull base reconstruction have also progressed, allowing surgeons to remove larger and more complicated tumors than before. This review article discusses different endoscopic skull base approaches, surgical techniques for removing pituitary adenomas, and reconstruction methods for repairing postoperative low-flow and high-flow cerebrospinal fluid leakage.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Endoscopic Endonasal Approach to the Orbit.

Introduction Although endonasal endoscopic approaches (EEA) to the orbit have been previously reported, a didactic resource for educating neurosurgery and otolaryngology trainees regarding the pertinent anatomy, techniques, and decision-making pearls is lacking. Methods Six sides of three formalin-fixed, color latex-injected cadaveric specimens were dissected using 4-mm 0- and 30-degree rigid endoscopes, as well as standard endoscopic equipment, and a high-speed surgical drill. The anatomical dissection was documented in stepwise three-dimensional (3D) endoscopic images. Following dissection, representative case applications were reviewed. Results EEA to the orbit provides excellent access to the medial and inferior orbital regions. Key steps include positioning and preoperative considerations, middle turbinate medialization, uncinate process and ethmoid bulla removal, complete ethmoidectomy, sphenoidotomy, maxillary antrostomy, lamina papyracea resection, orbital apex and optic canal decompression, orbital floor resection, periorbita opening, dissection of the extraconal fat, and final exposure of the orbit contents via the medial-inferior recti corridor. Conclusion EEA to the orbit is challenging, in particular for trainees unfamiliar with nasal and paranasal sinus anatomy. Operatively oriented neuroanatomy dissections are crucial didactic resources in preparation for practical endonasal applications in the operating room (OR). This approach provides optimal exposure to the inferior and medial orbit to treat a wide variety of pathologies. We describe a comprehensive step-by-step curriculum directed to any audience willing to master this endoscopic skull base approach.

Sphenoid sinus pneumatization in Middle Eastern patients - implications for endoscopic skull base approaches

Sphenoid sinus pneumatization in Middle Eastern patients - implications for endoscopic skull base approaches

Surgical Outcome of Pure Endonasal Transsphenoidal Approach for Pituitary Tumors

Objective: To determine the frequency of complete tumor excision by endoscopic skull base (transsphenoidal) approach in pituitary adenoma patients presenting to a neurosurgical department.&#x0D; Materials &amp; Methods: This descriptive case series was conducted at the Department of Neurosurgery Unit II, Lahore General Hospital Lahore from May 2019 to November 2019. The study included60 patients with pituitary adenoma from the outpatient department who qualified for the inclusion criteria. All patients went through the endoscopic binarial transsphenoidal approach for pituitary adenectomy. All patients were treated according to the department protocols and were followed for 6 weeks to determine the outcome i.e. no residual tumor left as determined by Magnetic Resonance Imaging.&#x0D; Results: The mean age of pituitary adenoma patients studied was 50.02 ± 8.2 years. 43 patients (71.7%) were male.56 patients (93.3%) showed complete resection on MRI using the endoscopic binarial transsphenoidal approach. The outcome was not affected by patients' gender and age. Tumor size significantly affected the outcome i.e. complete resection.&#x0D; Conclusion: It is concluded that the endoscopic skull base (transsphenoidal) approach for excision of pituitary adenomas gives desirable results as depicted by 93.3% success rate in terms of complete resection of the tumor. We did not observe a significant effect of patients' gender and age on the clinical outcome in the studied sample of the population.

The use of an O-arm in endonasal endoscopic operations of the skull base

BackgroundEndoscopic endonasal transsphenoidal approaches are broadly used nowadays for a vast spectrum of pathologies sited in the anterior and middle cranial fossa. The usage of neuronavigation systems (neuronavigation) in these surgeries is crucial for improving orientations deeply inside the skull and increasing patient safety.MethodsThe aim of this study was to assess the use of optical neuronavigation, together with an intraoperative O-arm O2 imaging system, in a group of patients with hypophyseal adenoma that underwent a transnasal transsphenoidal surgery, and correlate the accuracy and its deviation during the navigational process against the use of conventional neuronavigation that uses preoperative MRI and CT scans. The overall group consisted of six patients, between 39 and 78 years old, with a diagnosis of hypophyseal adenoma. Patients were treated with an endoscopic transsphenoidal technique and all of them underwent preoperative MRI and CT scans of the brain. These images were used in the neuronavigation system StealthStation S7® during the surgery, where we defined two bony anatomical landmarks, such as a vomer or the origin of an intrasphenoidal septum, in each operated patient. The tip of the navigational instrument, under endoscopic control, pointed to these landmarks and the distance between the tip and the bony structure was measured on the neuronavigation system. Afterwards, intraoperative 3D x-ray imaging was performed via the mobile system O-arm O2® system with automatic transfer into the navigational system. Under endoscopic guidance, we localized the identical bony anatomical landmarks used in the previous measurement and re-measured the distance between the tip and bony landmark in images acquired by the O-arm. The results of both measurements were statistically compared.ResultsThe mean error of accuracy during conventional neuronavigation with usage of preoperative CT and MRI scans was 2.65 mm. During the neuronavigation, with utilization of intraoperative 3D O-arm images, the mean error of accuracy 0 mm. These mean errors of accuracy (both measurement methods were compared by nonparametric Wilcoxon test) had a statistically significant difference (p = 0.043).ConclusionsBased on this preliminary clinical study, we conclude that the O-arm is capable of providing intraoperative x-ray 3D images in sufficient spatial resolution in a clinically feasible acquisition. The mean error of accuracy during intraoperative navigation, based on 3D O-arm scans at the skull base, is significantly lower compared to the usage of navigation using conventional presurgical CT and MRI images. This suggests the suitability of this method for utilization during endoscopic endonasal skull base approaches.

Endoscopic Anatomy and a Safe Surgical Corridor to the Anterior Skull Base

We describe the possibility to create precise preoperative planning for endonasal endoscopic approaches to the anterior skull base by overlapping endoscopic and radiologic anatomy. The important anatomic structures were marked. Morphometric measurements between these anatomic landmarks were performed endoscopically and compared with radiologic measurements of the same areas to ensure result compatibility. Seven cadaver heads injected intravascularly with colored silicone were used for this study. Thin-section brain and paranasal sinus computed tomography scans were obtained on all cadavers. Using 0-degree rigid endoscopes and endonasal endoscopic surgical instruments, the anterior skull base was examined binostrally in all cadavers. Bilateral middle turbinates were identified and preserved. Next, an inferior uncinectomy and middle meatal antrostomy were performed. After performing a frontal antrostomy, bilateral anterior and posterior ethmoidal cells were opened and the skull base was identified and followed to the posterior wall of the frontal sinus. A transnasal transethmoidal sphenoidotomy was done with full exposure to the entire anterior skull base. The anatomic landmarks for endonasal endoscopic skull base approaches were distinguished and measurements were made. The anterior skull base was divided into 3 compartments: anterior (area between the posterior inferior border of the frontal sinus and the course of anterior ethmoidal artery), middle (area between the course of the anterior ethmoidal artery and that of the posterior ethmoidal artery [PEA]), and posterior (area between the course of the PEA and the attachment point of the anterior border of the sphenoid sinus to the skull base) compartments. The distances between important anatomic markers and endoscopic depth measurements of this area were measured. During endonasal endoscopic anterior skull base surgery, the area between the anterior border of the sphenoid sinus and PEA artery was safe as the first dissection zone. Preoperative radiologic width and depth measurements facilitate orientation to the endoscopic anatomy during surgery and help predict the endonasal surgical corridor anatomy preoperatively.

A follow-up study on outcomes of endoscopic transsphenoidal approach for acromegaly

ObjectiveA thorough follow-up study in which the same clinic presents the change in the surgical outcomes of acromegaly over the years, is still lacking in the endoscopic era. In this study, we intended to evaluate the clinical characteristics, radiological features, surgical and late remission rates of newly diagnosed acromegaly patients treated in our clinic between 2014 and 2019 in order to delineate the surgical remission status according to radiological, microscopic, and hormonal features. As a follow-up to our initial report, we also aimed to display the change of surgical remission rates over time in a tertiary center. MethodsA total of newly diagnosed 106 patients with acromegaly, who underwent endoscopic endonasal trans-sphenoidal approach (EETSA) in the last five years were retrospectively analyzed and presented in this study. Medical records were reviewed in clinical, biochemical, pathological, and radiological aspects to assess the relationship of preoperative patient characteristics with surgical remissions. ResultsThe percentages of the giant pituitary adenomas (≥4 cm), adenomas with suprasellar extension and adenomas with surgically proven invasion of the cavernous sinus in the present series were 13%, 34%, and 20%, respectively. Gross total resection was achieved in 80% of the patients. Surgical remission and late remission rates were 66% and 86%, respectively. Nine (9.4%) patients in our current report had postoperative transient diabetes insipidus. The mean follow-up period in this series was 36.1 ± 18.1 (range 12–59) months. ConclusionThe presented surgical results are considerably better than our published initial series of acromegaly patients operated in the same clinic between 2007 and 2014. The improvement in surgical remission rate support a positive surgical volume - remission rate relationship for acromegaly in the era of endoscopic endonasal skull base approaches. One possible factor for better results may be the increasing surgical experience in EETSA, which follows a trend toward gradual improvement of long-term late remissions via a multidisciplinary approach.

Diagnosis and Management of Pediatric Nasal CSF Leaks and Encephaloceles

To describe the clinical presentation, diagnosis, and management of pediatric nasal encephaloceles. Encephaloceles and meningoencephaloceles are on the differential diagnosis for congenital midline nasal masses. These lesions are treated surgically to prevent craniofacial deformities and meningitis and to address symptoms such as a nasal obstruction, feeding difficulties, and cerebrospinal fluid (CSF) rhinorrhea. With the advent of endoscopic skull base approaches and instruments, surgical treatment of nasal encephaloceles have transitioned from large bicoronal external approaches to more minimally invasive endonasal endoscopic approaches. Endoscopic surgical approaches are safe in pediatric patients. Pediatric intranasal encephaloceles are more frequently managed endoscopically. However, due to the rarity of this condition, further multi-institutional research is needed to examine long-term outcomes for this surgical approach.

Comparison of a purely endoscopic three-layer technique versus pericranial flap for reconstruction of anterior skull base defects after sino-nasal tumor resection: assessment of postoperative frontal lobe sagging and frontal lobe falling.

The evolution of endoscopic skull base approaches has enabled surgeons to manage selected skull base tumors through a transnasal endoscope-assisted approach. On the other side, more extensive lesions may require a combined cranioendoscopic approach. In this paper, we analysed and compared the incidence of frontal lobe sagging after endoscopic multilayer (EM) reconstruction versus pericranial flap (PF) reconstruction. Subjects were selected retrospectively according to specific inclusion and exclusion criteria. The degree of frontal lobe sagging after surgery 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 frontal lobe sagging. Twenty subjects were enrolled in our study. In the EM technique group the average frontal lobe displacement was -2,34 ± 1,55 mm. The average postoperative frontal lobe sagging was -0,45 ± 8,92 mm in subjects reconstructed with the PF. The skull base defect size correlated with the degree of frontal lobe sagging in subjects reconstructed with the PF, but not in the other group and when merging the two groups. In conclusion, the EM technique and the PF reconstruction showed a good reliability for the closure of anterior skull base defects. Moreover the PF seemed to prevent frontal lobe sagging but, for larger skull base defects, it could be useful to be combined with other autologous or heterologous materials to avoid the frontal lobe falling.

Open and Endoscopic Skull Base Approaches

Surgical approaches to the skull base have been evolving at an incredible rate in the past 30 years. The advent of the endoscope has multiplied the available approaches while reducing morbidity. Otolaryngologists and neurosurgeons performing these operations must stay updated in recent trends and techniques to determine the best options for patients. Twenty years have passed since the adoption of the endoscope in skull base surgery but new techniques are still being introduced on an annual basis. Most notably are the “cross court” techniques utilizing the contralateral transmaxillary (CTM) approach and transorbital neuroendoscopic surgery (TONES). Both approaches allow the surgeon increased angulation and access to lateral structures limited by the endonasal approach. Surgeons must understand the patient factors, pathology, and available resources as well as the armamentarium of approaches to the skull base to offer the best option for individual patients.

Endoscopic Endonasal Sinus Stent Placement as a Salvage Technique for Drainage of a Petrous Abscess

Various cranial approaches exist to address lesions of the petrous apex. Many of these involve skull base approaches with varying degrees of surgical morbidity. We present a unique case of a recurrent petrous abscess that was treated with an endoscopic skull base approach with placement of a permanent stent commonly used for sinus surgery. To our knowledge this is the first report to repurpose this type of stent and employ it long-term (3+ years) without any significant side-effects.

SURG-22. CUSHING’S DISEASE: A DIFFICULT TO TREAT NEURO-ONCOLOGICAL CONDITION

Abstract BACKGROUND Cushing disease (CD) comprises a spectrum of clinical manifestations secondary to hypercortisolism due to ACTH-secreting pituitary adenoma. Transsphenoidal adenomectomy remains the standard treatment. Because of the significant rate of recurrence or persistence of CD, it is of interest to determine factors that may correlate with long-term outcomes following surgical intervention. OBJECTIVE The objective of our study is to determine the remission rate after surgery with special emphasis on factors affecting remission. METHODS Data of all patients undergoing surgery for CD from 2009 to 2017 was analyzed retrospectively. Transphenoidal resection was the preferred treatment with a recent trend in favor of endonasal endoscopic skull base approach. Post-operative cortisol level of &lt; 2 μg/dL was taken as remission and value between 2 and 5 μg/dL as possible remission. RESULTS 104 patients operated primarily for CD were included for analysis. 47 patients underwent microscopic surgery, 55 endoscopic surgery and two were operated trans-cranially. Remission was achieved in 76.47% of patients. In univariate analysis, factors significantly associated with remission were (1) type of surgery (p=0.01); endoscopy (88.23% remission) better than microscopy (56.6% remission) (2) postoperative day-1 morning cortisol (p=0.004) and; (3) postoperative day-1 morning ACTH (p=0.015). In multivariate analysis, however only postoperative day-1 cortisol was found to be significant as predictor of remission (p=0.02). CONCLUSION Postoperative plasma cortisol level is a strong independent predictor of remission and value less than 10.7µgm/dl can be taken as cut off for predicting remission. Remission provided by endoscopy appears to be significantly better than microscopic approach.