Endoscopic Transsphenoidal Skull Base Surgery Research Articles

The learning curve in endoscopic transsphenoidal skull-base surgery: a systematic review

BackgroundThe endoscopic endonasal transsphenoidal approach (EETA) has revolutionized skull-base surgery; however, it is associated with a steep learning curve (LC), necessitating additional attention from surgeons to ensure patient safety and surgical efficacy. The current literature is constrained by the small sample sizes of studies and their observational nature. This systematic review aims to evaluate the literature and identify strengths and weaknesses related to the assessment of EETA-LC.MethodsA systematic review was conducted following the PRISMA guidelines. PubMed and Google Scholar were searched for clinical studies on EETA-LC using detailed search strategies, including pertinent keywords and Medical Subject Headings. The selection criteria included studies comparing the outcomes of skull-base surgeries involving pure EETA in the early and late stages of surgeons’ experience, studies that assessed the learning curve of at least one surgical parameter, and articles published in English.ResultsThe systematic review identified 34 studies encompassing 5,648 patients published between 2002 and 2022, focusing on the EETA learning curve. Most studies were retrospective cohort designs (88%). Various patient assortment methods were noted, including group-based and case-based analyses. Statistical analyses included descriptive and comparative methods, along with regression analyses and curve modeling techniques. Pituitary adenoma (PA) being the most studied pathology (82%). Among the evaluated variables, improvements in outcomes across variables like EC, OT, postoperative CSF leak, and GTR. Overcoming the initial EETA learning curve was associated with sustained outcome improvements, with a median estimated case requirement of 32, ranging from 9 to 120 cases. These findings underscore the complexity of EETA-LC assessment and the importance of sustained outcome improvement as a marker of proficiency.ConclusionsThe review highlights the complexity of assessing the learning curve in EETA and underscores the need for standardized reporting and prospective studies to enhance the reliability of findings and guide clinical practice effectively.

Efficacy of a Novel Augmented Reality Navigation System Using 3D Computer Graphic Modeling in Endoscopic Transsphenoidal Surgery for Sellar and Parasellar Tumors

In endoscopic transsphenoidal skull base surgery, knowledge of tumor location on imaging and the anatomic structures is required simultaneously. However, it is often difficult to accurately reconstruct the endoscopic vision of the surgical field from the pre-surgical radiographic images because the lesion remarkably displaces the geography of normal anatomic structures. We created a precise three-dimensional computer graphic model from preoperative radiographic data that was then superimposed on a visual image of the actual surgical field and displayed on a video monitor during endoscopic transsphenoidal surgery. We evaluated the efficacy of this augmented reality (AR) navigation system in 15 consecutive patients with sellar and parasellar tumors. The average score overall was 4.7 [95% confidence interval: 4.58-4.82], which indicates that the AR navigation system was as useful as or more useful than conventional navigation in certain patients. In two patients, AR navigation was assessed as less useful than conventional navigation because perception of the depth of the lesion was more difficult. The developed system was more useful than conventional navigation for facilitating an immediate three-dimensional understanding of the lesion and surrounding structures.

Is nasal airflow disrupted after endoscopic skull base surgery? A short review.

Even the most delicate endonasal surgery for skull base lesion causes changes in the nasal cavity, some of them permanent. Morphological changes in the nasal cavity and their consequences (changes in nasal airflow) are often studied by advanced numerical analysis called computational fluid dynamics. This review summarizes current knowledge of endoscopic transsphenoidal skull base surgery effects on nasal airflow. Several studies have shown that endoscopic skull base surgery changes nasal anatomy to the extent that nasal airflow changes significantly postoperatively. Removing any intranasal structure increases the cross-sectional area of the respective nasal meatus, leading to increased nasal airflow in this area while airflow in the narrower periphery decreases. Middle turbinate resection increases airflow in the middle meatus and reduces airflow in the superior and inferior meatus. Small posterior septectomy does not cause a significant change in nasal airflow. Nasal septum deviation is an important factor in airflow changes. Current studies describe nasal changes after rather extensive procedures (e.g., middle turbinectomy, ethmoidectomy) that are unnecessary in routine pituitary adenoma surgery. No studies have compared changes using pre- and postoperative scans of the same patients after actual surgery.

Is Olfactory Function Affected by Endoscopic Transsphenoidal Skull Base Surgery?

Is Olfactory Function Affected by Endoscopic Transsphenoidal Skull Base Surgery?

The Effect of Endoscopic Endonasal Transsphenoidal Skull Base Surgery on Cochlear Function.

Endoscopic transsphenoidal skull base surgery (ETSS) has become a standard approach in the treatment of sellar and clival lesions, such as pituitary adenoma and chordoma. Due to the close proximity of the clivus and the sella turcica to the inner ear, it is thought that bone drilling in the surgery may have effects on hearing. The aim of this study was to assess the effect of bone drilling in ETSS procedure on cochlear function. This study was performed on 18 patients who underwent ETSS procedure between December 2016 and May 2017. The study was designed as a prospective study. All of the data were prospectively collected. These included demographic data, date of surgery, type of surgery, preoperative pure-tone audiometry, and preoperative and postoperative distortion product otoacoustic emission (DPOAE) measurements. Of the DPOAE measurements of the patients who were operated for pituitary adenoma, there was a statistically significant difference between the signal-to-noise ratio (SNR) measurements at 0.5, 1, 2 and 4 kHz ( p < 0.05). Additionally, there were no significant differences in preoperative and postoperative SNR measurements of six patients who were selected for clivus chordoma. When the preoperative and postoperative tonal audiometric tests of the patients were compared, no statistically significant difference was found ( p > 0.05). In conclusion, it is found that bone drilling in ETSS procedure has a negative effect on cochlear function in the early period. This is the first study to evaluate the degree of noise-induced cochlear damage in patients who were gone under ETSS procedure.

Extent of surgery in endoscopic transsphenoidal skull base approaches and the effects on sinonasal morbidity.

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. 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). 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. 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). 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.

Sino-Nasal Quality of Life before and after Endoscopic Transsphenoidal Skull Base Surgery

Sino-Nasal Quality of Life before and after Endoscopic Transsphenoidal Skull Base Surgery

Evaluation of the application of rhino-septal splints in endoscopic transsphenoidal skull base surgery.

The endoscopic transnasal route for the surgical removal of tumors in the sellar region is frequently associated with nasal complications such as synechiae or impaired nasal breathing. In this study, we investigated the impact of septal splints on avoiding surgery-related co-morbidities. 49 patients in whom endoscopic transnasal, transsphenoidal surgery for sellar tumors was performed between 2012 and 2014 were studied. In 30 of these, nasal septal splints were applied at the end of surgery to both sides of the septum and left in situ for 10days (group 1), 19 patients received no splints (group 2). A standardized postsurgical follow-up investigation with endoscopic nasal examination, rhinomanometry and olfactory testing was performed on average 2months postoperatively. Patients' subjective nose-related discomfort at follow-up was assessed descriptively using a set of standardized self-rating statements on nasal problems. Synechias occurred less likely with nasal septal splints (n=15; 50%) than without (n=16; 84.2%). Moreover, multiple synechiae were predominantly observed in the group without septal splints (n=10 vs. n=2). Rhinomanometry showed improved flow-V150-inspiration scores when splints were used (with significant differences between groups for the left nostril: p=0.039 and p=0.022, resp.). In accordance, impaired nasal breathing after surgery was reported more frequently by 76.9% of patients without splints, but only 56% of patients with splints. Our results provide support for the application of nasal septal splints when operating endoscopically on tumors in the sellar region to reduce postoperative synechias and to improve nasal breathing.

Intranasal cross-sectional area and quality of life changes following endoscopic transsphenoidal skull base surgery.

Endoscopic transsphenoidal surgical approaches to the skull base may produce alteration of intranasal architecture. Acoustic rhinometry (AR) can provide quantitative data on the nasal airway, which has not been previously applied to skull base surgery. We sought to employ AR to quantify the changes in nasal patency following endoscopic transsphenoidal surgery and identify the relationship between these changes and septal deviation, nasoseptal flap harvest, and sinonasal quality of life (QOL). Consecutive patients undergoing endoscopic transsphenoidal resection of a sellar or suprasellar tumor were prospectively enrolled. All subjects were adults who completed AR and the 22-item Sino-Nasal Outcome Test (SNOT-22) preoperatively and postoperatively. Cross-sectional area (CSA) was recorded at the internal nasal valve (CSA1), middle turbinate head (CSA2), and middle turbinate body (CSA3). Normative data were also collected from a larger cohort. Forty patients met study criteria. Significant increases occurred postoperatively in mean CSA2 (1.08 cm(2)) and CSA3 (2.47 cm(2)) (p < 0.001), whereas CSA1 remained unchanged. Nasoseptal flap harvest and correction of septal deviation did not significantly alter mean postoperative AR values. Mean SNOT-22 scores were comparable despite septal pathology, whereas strong correlation was not found with change in AR values. Preoperative and postoperative QOL scores were not significantly affected by the presence of nasal septal deviation. The endoscopic transsphenoidal approach to the skull base can result in increased intranasal area without a detrimental effect on sinonasal QOL. These effects are independent of nasoseptal flap harvest and correction of nasal septal deviation.

Middle turbinate preservation in endoscopic transsphenoidal surgery of the anterior skull base.

Endoscopic endonasal skull base surgery is a growing field in which the nasal corridors are used to address skull base lesions. Whether the middle turbinates must be removed for adequate exposure is controversial and not well addressed in the literature. This is a prospective, observational study of 163 consecutive cases of purely endoscopic endonasal transsphenoidal surgeries performed at a single tertiary care institution. The primary study outcome measurement is the feasibility of middle turbinate preservation in endoscopic transsphenoidal skull base surgery. The pathologies included 99 pituitary tumors, 15 craniopharyngiomas, 11 meningiomas, 11 Rathke's cleft cysts, 7 encephaloceles, 5 cerebrospinal fluid leak repairs, 9 clival chordomas, and 6 other pathologies of the sella. In patients undergoing surgery for a neoplasm, the average tumor size was 2.3 cm. The middle turbinate was preserved in 160/163 cases (98%). One hundred and twenty magnetic resonance imaging (MRI) studies were reviewed at a median of 16 months postoperatively and no patients (0%) developed frontal sinusitis. The middle turbinate can be preserved in nearly every endonasal, endoscopic transsphenoidal skull base case while still providing good exposure for successful tumor resection and skull base reconstruction. Postoperative sinonasal function may be better preserved with this technique.

Janus flap: Bilateral nasoseptal flaps for anterior skull base reconstruction

Objective Large dural defects after extended endoscopic endonasal skull base resections require meticulous reconstruction to prevent a cerebrospinal fluid leak postoperatively. The nasoseptal flap is a vascularized tissue graft developed to aid in the multilayer reconstruction of the skull base. The purpose of this study is to describe the first experiences with bilateral nasoseptal flaps for reconstruction of very large skull base defects. Study Design Prospective, observational study. Setting Large tertiary referral center (New York Presbyterian Hospital). Subjects and Methods Five patients underwent a multilayer reconstruction after an extended endoscopic transsphenoidal skull base surgery that included bilateral nasoseptal flaps. Pathologies consisted of two pituitary macroadenomas, one planum sphenoidale meningioma, one craniopharyngioma, and one cavernous sinus hemangioma. Results All five patients underwent successful skull base reconstruction without a cerebrospinal fluid leak, complication at the reconstruction site, or anterior extension of the posterior septal perforation. Conclusion Bilateral nasoseptal flaps are a viable option for large dural defects of the anterior and ventral skull base when one nasoseptal flap may not completely seal the entire defect.

Light at the End of the Tunnel: The Learning Curve Associated with Endoscopic Transsphenoidal Skull Base Surgery

Endoscopic transsphenoidal resection of skull base lesions has been introduced widely as an alternative to microscopic transmucosal approaches. We report the introduction of this technique to our unit, including the learning curve recognized for this procedure, comparing techniques in a concurrent case-control fashion. All patients operated on for sellar, suprasellar, or clival lesions were considered for endoscopic surgery, with 51 patients undergoing endoscopic surgery and 46 having microscopic surgery with the operating method determined by the availability of the ear, nose, and throat surgeon involved with the procedures. Endoscopic surgery compared favorably with microscopic surgery with respect to endocrine control, length of stay, diabetes insipidus, and cerebrospinal fluid leakage. A learning curve was found with a significant fall in complication rates between the first third and most recent third of the cohort. Endoscopic skull base surgery has superior results to microscopic approaches once the initial learning curve is overcome, but this can be done quickly and safely.