Transsellar Approach Research Articles

Endoscopic Endonasal Skull Base Surgery: Analysis of the Results in the Author’s Initial 200 Cases

Background Endoscopic endonasal approaches represent currently an important tool for approaching the skull base. The evolution of new techniques is based in the continuous acquisition of skills and abilities and it is paramount to determine the safety and effectiveness of new approaches. Based on that, the aim of this study is to analyze our results after the first 200 cases. Material and methods We performed a retrospective review of all cases operated on through an endoscopic endonasal approach in our Skull Base Unit, between January 2007 and May 2018. We analyze the results and all the per-operative complications associated. Results In this study we included 200 cases, comprising 105 female (52,2 %) and 95 male (47,5 %), with a mean age of 45,6 (range 21-85 years-old). The most commonly reported pathology was the pituitary adenoma, comprising 121 cases (60,5 %), followed by 13 meningocele (6,5 %), 9 chordoma (4,5 %), 6 skull base meningioma (3 %) and 7 cranyopharingioma (3,5 %). 161 cases (81 %) represented first surgery. The most frequently reported complication was diabetes insipidous in 17 % of all cases, followed by CSF leak, represented by 15 cases (7,5 %). 12 CSF leak cases were successfully treated by external lumbar draining and 3 patients required second surgery to skull base repair. In the last 50 cases, only one CSF leak has been reported, representing an incidence of 2 %, successfully treated by endoscopic repair. This decrease in CSF leak represents the impact of the learning curve in skull base reconstruction. 5 % of patients suffered meningitis and 5 % presented permanent anosmia. In our serie we reported 1,6 % of transient neurologic deficit represented by oculomotor palsy and 1,6 % of permanent neurologic deficit due to infarction. 3 patients in this serie has died, two due to malignant ICA occlusion and 1 due to infection (overall mortality 1,5 %). The most commonly used approach was the transsphenoidal transsellar approach (58 %), followed by transplanum-transtubercullum approach (8 %). Gross total resection was achieved in 76 % of tumoral pathology, 71 % in cases of pituitary adenomas. Conclusion From this review we can conclude that, in our serie, endoscopic endonasal surgeries represent safe approaches to the skull base to a huge variety of pathologies. Progressive acquisition of skills and experience is paramount to improve the results, avoiding and reducing complications. Appropriate patient and pathology selection is also mandatory.

Endoscopic endonasal pituitary sacrifice for select tumors with retrochiasmatic and/or retrosellar extension: surgical anatomy, operative technique, and case series.

Tumors located in the retrochiasmatic region with extension to the third ventricle might be difficult to access when the pituitary-chiasmatic corridor is narrow. Similarly, tumor extension into the interpeduncular and retrosellar space poses a major surgical challenge. Pituitary transposition techniques have been developed to gain additional access. However, when preoperative pituitary function is already impaired or the risk of postoperative panhypopituitarism (PH) is considered to be particularly high, removal of the pituitary gland (PG) might be the preferred option to increase the working corridor. The aim of this study was to describe the relevant surgical anatomy, operative steps, and clinical experience with the endoscopic endonasal pituitary sacrifice (EEPS) and transsellar approach. This study comprised anatomical dissections to highlight the relevant surgical steps and a retrospective case series reporting clinical characteristics, indications, and outcomes of patients who underwent EEPS. The surgical technique is as follows: both lateral opticocarotid recesses are exposed laterally, the limbus sphenoidale superiorly, and the sellar floor inferiorly. After opening the dura, the PG is detached circumferentially and mobilized off the medial walls of the cavernous sinuses. The descending branches of the superior hypophyseal artery are coagulated, and the stalk is transected. After removal of the PG, drilling of the dorsum sellae and bilateral posterior clinoidectomies are performed to gain access to the hypothalamic region, interpeduncular, and prepontine cisterns. From 2018 to 2023, 11 patients underwent EEPS. The cohort comprised mostly tuberoinfundibular craniopharyngiomas (n = 8, 73%). Seven (64%) patients had partial or complete anterior PG dysfunction preoperatively, while 4 (36%) had preoperative diabetes insipidus. Because of the specific tumor configuration, the chance of preserving endocrine function was estimated to be very low in patients with intact function. The main reasons for pituitary sacrifice were impaired visibility and surgical accessibility to the retrochiasmatic and retrosellar spaces. Gross-total tumor resection was achieved in 10 (91%) patients and near-total resection in 1 (9%) patient. Two (18%) patients experienced a postoperative CSF leak, requiring surgical revision. When preoperative pituitary function is already impaired or the risk for postoperative PH is considered particularly high, the EEPS and transsellar approach appears to be a feasible surgical option to improve visibility and accessibility to the retrochiasmatic hypothalamic and retrosellar spaces, thus increasing tumor resectability.

Application of a Novel Versatile Mini Posterior Nasoseptal Graft in Endoscopic Transsphenoidal Pituitary Adenoma Surgery.

Skull base reconstruction is a key technique in patients undergoing endoscopic transnasal skull base surgery. Although a pedicled nasoseptal flap (PNSF) is often used to repair large skull base defects with high-flow cerebrospinal fluid leakage, bone exposure of the donor site of the PNSF can result in long-term crusting. To design a novel and versatile mini posterior nasoseptal graft for the reconstruction of defects in the sellar floor or PNSF or pedicled nasoseptal rescue flap (PNSRF) donor site in patients undergoing pituitary adenoma surgery. Patients who underwent pituitary adenoma removal through an endoscopic endonasal approach and repair of a sellar defect or PNSF/PNSRF donor site using the mini posterior nasoseptal graft technique from January 2019 to January 2020 were retrospectively evaluated. Pituitary adenomas were removed using a binostril 4-hand technique through a transnasal transsphenoidal transsellar approach or an expanded transsellar approach. Mini posterior nasoseptal grafts were successfully used in 70 patients who underwent pituitary adenoma removal through an endoscopic transsphenoidal sellar approach. Mini posterior nasoseptal grafts repaired sellar defects in 40 patients and donor site defects of the contralateral PNSF/PNSRF in 30 patients. None of these patients experienced cerebrospinal fluid leakage or major complications. A mini posterior nasoseptal graft is a safe and effective technique for repairing sellar defects after endoscopic transnasal pituitary adenoma surgery. This technique can also be used to repair defects in PNSF/PNSRF donor sites.

Functioning Endocrine Outcome after Endoscopic Endonasal Transsellar Approach for Pituitary Neuroendocrine Tumors.

The endoscopic endonasal approach (EEA) is a well-established technique for the treatment of pituitary neuroendocrine tumor Preservation of normal gland tissue is crucial to retain effective neuroendocrine pituitary function. The aim of this paper is to analyze pituitary endocrine secretion after EEA for pituitary neuroendocrine tumor to identify potential predictors of functioning gland recovery. Patients who underwent an exclusive EEA for pituitary neuroendocrine tumors between October 2014 and November 2019 were reviewed. Patients were divided into groups according to postoperative pituitary function (Group 1, unchanged; group 2, recovering; group 3, worsening). Among the 45 patients enrolled, 15 presented a silent tumor and showed no hormonal impairment, and 30 patients presented pituitary dysfunction. A total of 19 patients (42.2%) were included in group 1, 12 (26.7%) patients showed pituitary function recovery after surgery (group 2), and 14 patients (31.1%) exhibited the onset of new pituitary deficiency postoperatively (group 3). Younger patients and those with functioning tumor were more likely to have complete pituitary hormonal recovery (p = 0.0297 and p = 0.007, respectively). No predictors of functional gland worsening were identified. EEA for pituitary neuroendocrine tumor is a reliable and safe technique regarding postoperative hormonal function. Preserving pituitary function after tumor resection should be a primary goal in a minimally invasive approach.

Quality of Life Considerations in Endoscopic Endonasal Management of Anterior Cranial Base Tumors.

Considering quality of life (QOL) is critical when discussing treatment options for patients undergoing endoscopic endonasal skull base surgery (EESBS) for cancers at the base of the skull. Several questionnaires have been developed and validated in the last 20 years to explore QOL in this patient population, including the Anterior Skull Base Questionnaire, Skull Base Inventory, EESBS Questionnaire, and the Sino-Nasal Outcome Test for Neurosurgery. The Sino-Nasal Outcomes Test-22 and Anterior Skull Base Nasal Inventory-12 are other tools that have been used to measure sinonasal QOL in anterior cranial base surgery. In addition to pathology-related perturbations in QOL endoscopic surgical options (transsellar approaches, anterior cranial base surgery, and various reconstructive techniques) all have unique morbidities and QOL implications that should be considered. Finally, we look ahead to new and emerging techniques and tools aimed to help preserve and improve QOL for patients with anterior cranial base malignancies.

Microsurgical anatomy of the dorsal clinoidal space: implications for endoscopic endonasal parasellar surgery.

The clinoidal venous space dorsal to the internal carotid artery (ICA) has not been well studied given its inaccessibility due to obstruction by the ICA during transcranial surgery. The evolution of endoscopic endonasal surgery has provided a new perspective into the clinoidal space and a new route for paraclinoidal lesions. Understanding the dorsal clinoidal space (DCS) is vital in planning and performing endoscopic endonasal surgery in the parasellar region. A detailed and precise description of the DCS from the endonasal perspective has not yet been provided. The authors' goal in this study was to delineate the microsurgical anatomy of the DCS from an endoscopic endonasal perspective, emphasizing its surgical implications when treating invasive pituitary adenomas and other parasellar lesions. An endoscopic endonasal transsellar approach was performed in 15 silicone-injected postmortem heads. Afterward, the sellar region was dissected through a transcranial approach using magnification ×3 to ×40 microscopy. The osseous, dural, and arterial relationships of the DCS and its architecture were investigated. The DCS's length, width, and depth were measured and its anatomical variations recorded. The DCS was identified in 90% of the specimens, and in most cases, its shape was a narrow rectangular pyramid, with its base oriented toward the sphenoid sinus and its apex toward the posterior clinoid process. It is delimited superiorly by the distal ring, inferiorly by the medial aspect of the proximal dural ring or caroticoclinoid ligament, laterally by the clinoidal ICA, and medially by the superior continuation of the medial wall of the cavernous sinus. The width, height, and length of the DCS were 4 ± 1, 4.5 ± 1.5, and 7 ± 2 mm, respectively. A fenestrated caroticoclinoid ligament is a potential route for tumor invasion from the cavernous sinus into the DCS. This report provides important anatomical descriptions of the DCS from endoscopic endonasal and transcranial perspectives that may facilitate the space's safe exposure for the removal of invasive adenomas, increasing total resection rates and minimizing the risk of injury to neurovascular structures.

The use of three-dimensional endoscope in transnasal skull base surgery: A single-center experience from China.

ObjectiveThe development of skull base surgery in the past decade has been influenced by advances in visualization techniques; recently, due to such improvements, 3D endoscopes have been widely used. Herein, we address its effect for transnasal endoscopic skull base surgery.MethodsA total of 63 patients who under endoscopic endonasal surgery (EES) with 3-D endoscope were retrospectively reviewed, including pituitary adenomas, craniopharyngiomas, meningiomas, Rathke’s cleft cysts, and chordomas. According to different lesions, transsellar approach (24 cases), transsphenoidal–transtuberculum approach (14 cases), transclival approach (6 cases), and transpterygoid approach (19 cases) were selected.ResultsTotal removal of tumors was achieved in 56 patients (88.9%) and subtotal removal in 7 cases (11.1%). Complications included diabetes insipidus in seven patients (11.1%), cerebrospinal fluid (CSF) leakage in two patients (3.2%), major vascular injury occurred in one patient (1.6%), cranial nerve injury in nine patients (14.3%), and meningitis in two patients (3.2%). There was no mortality in the series. All patients recovered and were back to normal daily life, and no tumor recurrence or delayed CSF leakage was detected during the follow-up (2–13 months, mean 7.59 months).ConclusionsVia 3D EES, it improved depth perception and preserved important neurovascular tissue when tumors were removed, which is important for improving the operative prognosis.

Postoperative Serum C-Reactive Protein and Cerebrospinal Fluid Leakage after Endoscopic Transsphenoidal Surgery.

Objective Postoperative cerebrospinal fluid (CSF) leakage in endoscopic transsphenoidal surgery is a potential risk that requires immediate repair. We investigated the potential of common postoperative hematological examinations for diagnosing postoperative CSF leakage. Methods We retrospectively studied 214 consecutive cases who underwent endoscopic transsphenoidal approach (ETSA; transsellar approach) or extended ETSA (E-ETSA). Patients with postoperative CSF leakage were defined the leak group (group L), and patients without were defined as the nonleak group (group N). Postoperative C-reactive protein (CRP) was compared between the ETSA and E-ETSA groups, and between the N and L groups. Results The values of white blood cell count and CRP 1 to 7 days after surgery were significantly higher in the L group. Especially, CRP was clearly elevated in the L group ( p < 0.001). The CRP value was higher in patients in the N group after E-ETSA than after ETSA ( p < 0.001). CRP increased on the day after surgery but decreased gradually thereafter in patients after ETSA and in the N group. In contrast, CRP value tended to increase gradually after surgery in the L group. In particular, the CRP on the day before the CSF leak was confirmed was clearly higher than on the fifth to seventh days in the N group. Conclusion Elevated CRP after endoscopic endonasal transsphenoidal surgery is a potential marker of CSF leakage.

Surgical Anatomy Applied to the Resection of Craniopharyngiomas: Anatomic Compartments and Surgical Classifications

Resective surgery remains the main treatment option for most patients with craniopharyngiomas. Understanding of the microsurgical anatomy of the sella and suprasellar region and its relationship with these tumors is necessary to achieve effective surgical treatment and minimize complications. In this article, we review the surgical anatomy related to craniopharyngiomas and divide it in 5 compartments according to tumor extension. Endoscopic and microsurgical dissection were performed in 3 freshly injected cadaver heads at the Weill Cornell Surgical Innovations Laboratory (New York, New York, USA) and at the Surgical Skills Center at Mount Sinai Hospital (Toronto, Ontario, Canada). Tumor extension was classified as 1) inferomedial or sellar, 2) superomedial or suprasellar, 3) lateral or sylvian, 4) posterior or interpeduncular/prepontine, and 5) intraventricular. The selection of surgical approaches is discussed based on the anatomic nuances of each these regions. In addition, we reviewed the literature regarding previous anatomic classifications for resection of craniopharyngiomas. Different approaches should be considered according to tumor extension into different compartments. Purely sellar tumors are amenable to endoscopic transsellar approaches, whereas those with a suprasellar extension require an extended transtuberculum approach. In some of those patients, a narrow chiasm-pituitary window may block access to the tumor and a transcranial translamina terminalis approach may be favored. Tumors occupying the interpeduncular fossa may pose a significant challenge for an endoscopic endonasal approach and transcranial approaches. Transcavernous approaches and anterior and posterior clinoidectomies may be required for adequate exposure in such patients. Translamina terminalis and/or transcallosal approaches are recommended for resection of purely intraventricular tumors. Tumors extending into the lateral compartment should be considered for transcranial frontotemporal approaches. The understanding of such anatomic nuances aids in the selection of the most appropriate surgical approach and in the prevention of potential complications. Because most craniopharyngiomas are midline lesions, the endoscopic endonasal approach represents an excellent approach for most of those tumors. However, transcranial approaches should be considered for tumors with extension into the lateral compartment and for selected tumors involving the ventricular compartment (purely intraventricular tumors and those with extension to the foramen of Monro and/or lateral ventricles).

Extended approach or usage of nasoseptal flap is a risk factor for olfactory dysfunction after endoscopic anterior skullbase surgery: results from 928 patients in a single tertiary center

The aim of this study was to compare olfactory function change in patients who underwent endoscopic skull-base surgery. A total of 928 patients were included in this retrospective study. Olfactory function was measured using the non- validated Likert scale (0â€"100), the Cross-Cultural Smell Identification Test (CC-SIT) and the butanol threshold test (BTT). Patients were divided into two groups: an endoscopic trans-sellar approach group (ETA, n = 768) and an extended endoscopic endonasal approach group (EEEA, n = 160). The ETA group was sub-divided into Nasoseptal flap (NSF) and no NSF groups. Non-validated olfactory function significantly worsened in the EEEA and ETA-NSF groups compared with that in the ETA- no NSF group for at least 6 months post-operatively. Validated olfactory impairment (BTT and CC-SIT) was also significantly worse in the EEEA and NSF groups compared with that in the ETA-no NSF group 3 months post-operatively. Additionally, the degrees of non-validated and validated olfactory deterioration were not significantly different between the EEEA and ETA-NSF groups. We also found that CC-SIT score changes were significantly impaired in tuberculum sellae meningioma patients than in craniopharyn- gioma patients. We conclude that NSF was the key factor that led to olfactory impairment after endoscopic skull-base surgery.

Extended Endoscopic Endonasal Surgery to Ventral Skull Base Lesions

Abstract Introduction In the last two decades, Endoscopic endonasal approaches (EEAs) have undergone a significant evolution with a major shift from a transsellar approach to a variety of approaches that can directly access the midline and paramedian ventral skull base. Once the technical feasibility of any surgical approach is established; its safety (assessed through complications), and treatment outcomes (assessed through long-term follow-up) should be addressed. Aim of the Study To assess the feasibility, safety, and efficacy of EEA as a minimally invasive approach to ventral skull base lesions. Methodology and Materials this is a prospective observational study of group of 30 patients with ventral skull base lesions that were managed via endoscopic endonasal approaches. All patients’ clinical data, radiographic evaluations, procedural detail, complications, and follow-up data were recorded and analyzed. Results The mean age of patients was 50.8 years (range: 18-74 years), with a male:female ration of 1:1.72. The most commonly encountered pathological entities in the cohort was meningiomas (43.3%), pituitary adenomas (23.3%). and craniopharyngiomas (13.3%). Postoperative CSF leak was observed in 6.6% of cases and was managed successfully. There were no cases with postoperative infection in the cohort. Other procedure-related complications include transient diabetes insipidus (10%), pneumocephaly (3.3%), Syndrome of inappropriate ADH secretion (3.3%). Gross total resection was achieved in 93.3% of cases. Improvement of preoperative symptoms was recorded in 89.2% of cases. The mean follow-up duration was 17.8 ± 2.7 months. Conclusion EEAs provide direct access and better visualization to the ventral skull base without brain retraction and with minimal neurovascular manipulation, leading to less morbidity and mortality. EEA can be considered a feasible, safe, and effective tool on the armamentarium of skull base surgery. EEAs should not be considered as a replacement to the traditional transcranial approaches; rather. EEAs are deemed as a complementary route and a potential alternative to conventional skull base surgery in select cases.

Sellar Defect Reconstruction with Vascularized Superior Turbinate Mucosal Flaps in Endonasal Endoscopic Transsellar Approach

The pedicled nasoseptal flap (NSF) constitutes the primary reconstructive option for most skull base defects in endonasal endoscopic approaches. The superior nasal turbinate (ST) has received little attention. We report our preliminary experience with the use of the ST mucosal flap in selected cases. We performed a retrospective review of patients who underwent endonasal endoscopic approaches and identified 9 patients who were reconstructed with vascularized ST mucosal flaps as part of a double-layer or triple-layer reconstruction. When there was no intraoperative cerebrospinal fluid (CSF) leak, we used a double-layer technique. If there was an intraoperative CSF leak, regardless of the quality of leakage, we preferred a triple-layer repair technique. In patients with high-flow leaks, triple-layer repair was performed using only autologous tissue grafts and flaps. Intraoperative CSF leaks were noted in 7 of 9 patients. Among them, 4 patients had low-flow CSF leaks (grade 1 and 2) and 3 patients had high-flow CSF leaks (grade 3). All reconstructions had complete defect coverage with the ST flaps and NSFs were preserved. All the flaps were viable at 4 weeks without a CSF leak or complication at the reconstruction site. There was no contraction or partial loss of the flap. After a mean follow-up period of 9 months, none of the patients required a flap revision, developed a mucocele, infection, or other complication. An ST flap can be used for the vascularized reconstruction of sellar defects if it is bilaterally available. This option should not be overlooked and wasted.

The Magnetic Resonance Imaging Appearance of Endoscopic Endonasal Skull Base Defect Reconstruction Using Free Mucosal Graft

At our institution, skull base reconstruction using a free mucosal graft from the nasal cavity floor has been the standardized technique after pituitary adenoma resection via transsellar approach. In this study, the expected appearance of the reconstruction on postoperative magnetic resonance imaging (MRI) scans is described and its integrity and impact on the sinonasal cavity are assessed. Fifty patients were selected, and their electronic medical records were reviewed for postoperative course, Sino-Nasal Outcome Test-22 (SNOT-22) scores, and nasal endoscopy reports. A total of 116 postoperative MRI scans were available to evaluate 1) the appearance and thickness of the graft, 2) the enhancement of the graft, and 3) the T2 signal in sphenoid sinus as a potential indication for inflammatory disease. There was no significant change in the thickness of the graft over time. Except for the 7 scans that were obtained without intravenous contrast, all scans showed enhancement of the graft. About half of the patients showed persistent T2 hyperintense signal at 12 and 24 months. However, this finding was not clinically significant, because postoperative SNOT-22 scores showed minimal sinonasal impact. Postoperative MRI surveillance scans showed a stable appearance of the graft that mimics the native mucosa, with enhancement through time, reflecting its robust vascularization and integration to the skull base. Although persistent T2 hyperintense signal was detected in the sphenoid sinus, clinical evidence based on nasal endoscopy reports and SNOT-22 scores indicated minimal sinonasal morbidity.

Quality of life after extended versus transsellar endoscopic skull base surgery from 767 patients.

The aim of this study was to compare sinonasal-related quality of life (QOL) in patients treated by extended or transsellar endoscopic skull base surgery. Prospective data analysis. Prospectively collected data from patients who underwent endoscopic skull base surgery between 2012 and 2017 were analyzed. Primary outcomes were preoperative Sino-Nasal Outcome Test-20 (SNOT-20) scores and then 1-month, 3-month, and 6-month follow-up. Comparative analysis was performed between the endoscopic transsellar approach (ETA) group (n = 647) and an extended endoscopic endonasal approach (EEEA) group (n = 120). In ETA group, the SNOT-20 score was compared between patients with a nasoseptal flap (NSF) (ETA-NSF) and without an NSF (ETA-no NSF). The mean total SNOT-20 score was significantly worse in the EEEA than ETA group at 1, 3, and 6 months postoperatively (P < .05). Although there was no significant difference in total SNOT-20 score between the ETA-NSF and ETA-no NSF group at 3 and 6 months after surgery, the percentage of patients with significant change (≥0.8) in the SNOT-20 score was higher in the NSF used group at 1, 3, and 6 months postoperatively (22.92% vs. 13.51%, P = .029; 20.59% vs. 5.59%, P = .039; and 24.00% vs. 4.03%, P = .003, respectively). According to multivariate analysis conducted regarding factors that deteriorate sinonasal QOL at 6 months following surgery, only NSF usage is significantly associated with poor outcome (odds ratio: 4.371, P = .011) CONCLUSIONS: Sinonasal-related QOL was significantly worse in patients treated by the EEEA versus ETA. Use of an NSF is the only poor prognostic factor in sinonasal QOL after endoscopic skull base surgery. 2b Laryngoscope, 129:1318-1324, 2019.

Delayed nasoseptal flaps for endoscopic skull base reconstruction: proof of concept and evaluation of outcomes.

To assess delayed nasoseptal flaps as a viable reconstructive option for sellar defects, evaluate postoperative vascularity of delayed nasoseptal flaps, and compare cerebrospinal fluid leak and surgery-specific complication rates of primary to delayed nasoseptal flaps. Case series with chart review. University of Pittsburgh Medical Center. All patients undergoing transsellar approaches for skull base tumors from 2009 to 2013 were evaluated. In cases where the necessity of a vascularized reconstructive flap was made evident only after tumor resection, the nasoseptal flap was raised after tumor resection and/or cerebrospinal fluid leak development, thus constituting a delayed nasoseptal flap. Outcome measures include postoperative magnetic resonance imaging (MRI) findings, cerebrospinal leak rates, and complication rates. During this timeframe, 437 patients underwent transsellar approaches. Primary nasoseptal flaps were used to reconstruct 179 patients while 32 patients had delayed flaps. All available postoperative MRI scans of delayed nasoseptal flap patients maintained vascularity on examination of T1 postcontrast images. There was no significant difference in cerebrospinal fluid leak rate between primary (3.4%) and delayed flaps (3.1%) (P = .95). There was no significant difference in surgery-specific complication rates between primary flaps (10.6%) and delayed flaps (3.1%; P = .14). Logistic regression analysis demonstrated no significant effect of flap type, age, or sex on cerebrospinal fluid leak rates. Delayed nasoseptal flaps are a viable reconstructive option for sellar skull base defects. They maintain vascularity as evidenced on postoperative MRI and are comparable to primary nasoseptal flaps with regard to cerebrospinal fluid leak rates and complication rates.

Secondary Nasoseptal Flaps for Endoscopic Skull Base Reconstruction: Proof of Concept and Evaluation of Outcomes

Objectives: (1) Assess secondary nasoseptal flaps (NSF) as a viable reconstructive option. (2) Evaluate postoperative vascularity of secondary NSFs. (3) Compare cerebrospinal fluid (CSF) leaks and complication rates of secondary NSFs to primary NSFs. Methods: This is a retrospective review of patients from 2009 to 2013 undergoing transsellar approaches for skull base tumors at the University of Pittsburgh Medical Center. In cases where the necessity of a vascularized reconstructive flap was made evident only after tumor resection, the NSF was raised after the tumor had been resected and/or CSF leak had developed (secondary NSF). Outcome measures include postoperative magnetic resonance imaging (MRI) findings, CSF leak rates, and complication rates. Results: Transsellar approaches were performed in 436 patients during this timeframe. Primary NSFs were used to reconstruct 178 patients while 32 patients had secondary NSFs. Postoperative MRI scans were available in 29 of 32 secondary NSF patients; all maintained vascularity on examination of T1 post-contrast images (mean time to MRI 4.9 months). There was no significant difference in CSF leak rate between primary NSFs (3.4%) and secondary NSFs (3.1%) ( P = .95). Primary NSFs had a higher overall complication rate (11.7%) compared to secondary NSFs (3.1%), but this was not statistically significant ( P = .142). Logistic regression analysis demonstrated no significant effect of flap type, age, or sex on CSF leak rates. Conclusions: Secondary NSFs are a viable reconstructive option for sellar skull base defects. They maintain vascularity as evidenced on postoperative MRI imaging and compare favorably to primary NSFs in regard to CSF leak rates and complication rates.

Pneumocephalus patterns following endonasal endoscopic skull base surgery as predictors of postoperative CSF leaks.

Postoperative pneumocephalus is a common occurrence after endoscopic endonasal skull base surgery (ESBS). The risk of cerebrospinal fluid (CSF) leaks can be high and the presence of postoperative pneumocephalus associated with serosanguineous nasal drainage may raise suspicion for a CSF leak. The authors hypothesized that specific patterns of pneumocephalus on postoperative imaging could be predictive of CSF leaks. Identification of these patterns could guide the postoperative management of patients undergoing ESBS. The authors queried a prospectively acquired database of 526 consecutive ESBS cases at a single center between December 1, 2003, and May 31, 2012, and identified 258 patients with an intraoperative CSF leak documented using intrathecal fluorescein. Postoperative CT and MRI scans obtained within 1-10 days were examined and pneumocephalus was graded based on location and amount. A discrete 0-4 scale was used to classify pneumocephalus patterns based on size and morphology. Pneumocephalus was correlated with the surgical approach, histopathological diagnosis, and presence of a postoperative CSF leak. The mean follow-up duration was 56.7 months. Of the 258 patients, 102 (39.5%) demonstrated pneumocephalus on postoperative imaging. The most frequent location of pneumocephalus was frontal (73 [71.5%] of 102), intraventricular (34 [33.3%]), and convexity (22 [21.6%]). Patients with craniopharyngioma (27 [87%] of 31) and meningioma (23 [68%] of 34) had the highest incidence of postoperative pneumocephalus compared with patients with pituitary adenomas (29 [20.6%] of 141) (p < 0.0001). The incidence of pneumocephalus was higher with transcribriform and transethmoidal approaches (8 of [73%] 11) than with a transsellar approach (9 of [7%] 131). There were 15 (5.8%) of 258 cases of postoperative CSF leak, of which 10 (66.7%) had pneumocephalus, compared with 92 (38%) of 243 patients without a postoperative CSF leak (OR 3.3, p = 0.027). Pneumocephalus located in the convexity, interhemispheric fissure, sellar region, parasellar region, and perimesencephalic region was significantly correlated with a postoperative CSF leak (OR 4.9, p = 0.006) and was therefore termed "suspicious" pneumocephalus. In contrast, frontal or intraventricular pneumocephalus was not correlated with postoperative CSF leak (not significant) and was defined as "benign" pneumocephalus. The amount of convexity pneumocephalus (p = 0.002), interhemispheric pneumocephalus (p = 0.005), and parasellar pneumocephalus (p = 0.007) (determined using a scale score of 0-4) was also significantly related to postoperative CSF leaks. Using a series of permutation-based multivariate analyses, the authors established that a model containing the learning curve, the transclival/transcavernous approach, and the presence of "suspicious" pneumocephalus provides the best overall prediction for postoperative CSF leaks. Postoperative pneumocephalus is much more common following extended approaches than following transsellar surgery. Merely the presence of pneumocephalus, particularly in the frontal or intraventricular locations, is not necessarily associated with a postoperative CSF leak. A "suspicious" pattern of air, namely pneumocephalus in the convexity, interhemispheric fissure, sella, parasellar, or perimesencephalic locations, is significantly associated with a postoperative CSF leak. The presence and the score of "suspicious" pneumocephalus on postoperative imaging, in conjunction with the learning curve and the type of endoscopic approach, provide the best predictive model for postoperative CSF leaks.

The “Mickey Mouse” Sign

Objective: In transnasal endoscopic pituitary surgery and transsellar approaches to anterior skull base lesions, a bony sella window is created with the lateral limits being the carotid arteries. Method: Coronal CT scan of the sphenoid sinuses were reviewed in a tertiary referral hospital and compared with intra operative findings. Results: Sphenoid anatomy is variable in terms of the degree of pneumatization and bony anatomy around the pituitary gland and internal carotid arteries. We describe a radiological sign ascertained from computerized tomography (CT) that when present indicates whether the carotid arteries can be readily identified endoscopically on entering the sphenoid sinus. On the axial CT the carotid arteries may produce protuberances either side of the sella which together with the bony sella and dorsum sella appear to form the outline of the head of Mickey Mouse or a teddy bear. Conclusion: When this sign is not present then the junction between the sella and carotids may not be clear and surgeons must be cautious or use neuronavigation.

Endoscopic approaches to the cavernous sinus

Skull base tumors that involve the cavernous sinus (CS) present a challenge to the endoscopic surgeon. Most such lesions arise from sellar pathology that involves the medial wall of the CS, which can be accessed by a transsphenoidal transsellar approach. Tumors that arise primarily in the medial CS may be accessed via a transethmoidal transsphenoidal parasellar approach, which avoids the dissection of sellar contents but requires the removal of bone overlying the carotid artery. Involvement of the tumor in the lateral CS may be accessed by a transmaxillary transpterygoid approach in patients who wish to avoid a craniotomy and in whom radiosurgery is not an option. These tumors are associated with a greater risk of cranial nerve injury, including extraocular palsy. Important adjuncts to the endoscopic approach include angled instrumentation, neuronavigation, intraoperative Doppler and intrathecal fluorescein injection. Tumor extirpation from the CS and cytoreduction are realistic goals for the endoscopic surgeon in well-selected cases. Skull base tumors that involve the cavernous sinus (CS) present a challenge to the endoscopic surgeon. Most such lesions arise from sellar pathology that involves the medial wall of the CS, which can be accessed by a transsphenoidal transsellar approach. Tumors that arise primarily in the medial CS may be accessed via a transethmoidal transsphenoidal parasellar approach, which avoids the dissection of sellar contents but requires the removal of bone overlying the carotid artery. Involvement of the tumor in the lateral CS may be accessed by a transmaxillary transpterygoid approach in patients who wish to avoid a craniotomy and in whom radiosurgery is not an option. These tumors are associated with a greater risk of cranial nerve injury, including extraocular palsy. Important adjuncts to the endoscopic approach include angled instrumentation, neuronavigation, intraoperative Doppler and intrathecal fluorescein injection. Tumor extirpation from the CS and cytoreduction are realistic goals for the endoscopic surgeon in well-selected cases.

Endoscopic endonasal approaches to the cavernous sinus

Surgical access to the cavernous sinus (CS) has proven a challenge for the skull base surgeon. Traditional approaches include the transcranial route, which broaches the lateral wall of the CS and has a high risk of cranial nerve weakness. A medial approach is more logical but the microscopic transsphenoidal approach has a restricted view. The endoscopic endonasal approach provides an alternative medial approach with improved visualization to that provided with the microscope. We describe our results using this approach for resection of CS tumors. A retrospective chart review was performed of all patients treated surgically at a tertiary care referral center between January 2004 and February 2011 with a purely endoscopic endonasal approach to the CS. Out of 400 total endoscopic skull base cases, 41 (10.3%) involved the cavernous sinus. The most common approach was the transsphenoidal transsellar approach (31 patients, 75.6%). Other approaches included the tran-sethmoidal transsphenoidal parasellar (4 patients, 9.8%) and transmaxillary transpterygoidal (6 patients, 14.6%). The most common pathology was pituitary macroadenoma (24 patients, 58.5%). Gross total resection was achieved in 18 patients (43.9%). Cerebrospinal fluid (CSF) leak was not encountered in any patient postoperatively. Complications included 1 case of new postoperative VIth nerve palsy, 1 case of intraoperative hemorrhage, 2 cases of persistent diabetes insipidus, and 2 cases of sinusitis. The endoscopic endonasal approach is a safe and effective option for tumor resection in the CS using a medial to lateral route for selected cases. Morbidity is low and a variety of reconstructive options are available.