Challenges, Learning Curve, and Safety of Endoscopic Endonasal Surgery of Sellar-Suprasellar Lesions in a Community Hospital

Single Center Neurosurgical Outcomes and Trends in Endoscopic Endonasal Resection of 297 Sellar/Suprasellar Tumors Stratified by Duration of Neurosurgical Career

BACKGROUND/OBJECTIVE

Endoscopic endonasal transsphenoidal surgery (EETS) is a common treatment for sellar and suprasellar tumors. While endoscopic training has improved over the years and formal fellowship training is now broadly available, the operative nuances of EETS conjectures the existence a learning curve as a neurosurgeon matures with experience. We aim to evaluate operative outcomes of 3 different experience levels of neurosurgeons over time at a single institution.

METHODS

We reviewed all adult patients who underwent EETS at Loyola University Medical Center by 3 early career, 1 midcareer, and 2 late career neurosurgeons from 2007 to 2023. A comparative assessment of patient demographics, tumor features, and surgical outcomes was done using metrics such as length of surgery, rates of gross total resection (GTR) and symptomatic improvement, new postoperative steroid dependence, and development of diabetes insipidus (DI). T-tests and χ2 were used to statistically evaluate the study cohorts.

RESULTS

A total of 297 patients underwent EETS. One hundred three (35%) were operated on by an early career, 122 (41%) by a mid-career, and 72 (24%) by a late career neurosurgeon. Late-career surgeons had shorter operation times (144 vs. 180 minutes with early and mid-career, P = 0.029) and increased GTR rates (P = 0.008). There were no significant differences between the symptomatic improvement rates amongst various surgeon experience levels. Although not statistically significant, early-career neurosurgeons had lower rates of new postoperative steroid dependence. Patients of early career surgeons experienced significantly less DI (15% vs. 40%, P = 0.004).

CONCLUSIONS

Late-career neurosurgeons had shorter operation lengths, achieved higher rates of GTR, and their patients experienced significantly higher rates of DI. Overall outcomes remained stable throughout the course of 16 years between different surgeon experience levels.

Conventional clinical signs and symptoms are poor predictors of postoperative cerebrospinal fluid leak: A single-centre cohort perspective

BACKGROUND

Postoperative cerebrospinal fluid (CSF) leak remains a concerning complication of the endoscopic endonasal approach (EEA) for skull base pathology. Signs and symptoms suggesting CSF leak often trigger additional workup during the postoperative course. We systematically evaluate associations between subjectively reported clinical signs/symptoms noted during the immediate postoperative period and incidence of postoperative CSF leaks.

METHODS

Retrospective chart review was conducted at a tertiary academic medical centre including 137 consecutive patients with intraoperative CSF leak during EEA with primary repair between July 2018 and August 2022. Postoperative CSF leak associations with clinical signs and symptoms were evaluated using positive (PPV) and negative predictive values (NPV), sensitivity, specificity and odds ratio (OR) via univariate logistic regression.

RESULTS

Seventy-nine patients (57.7%) had high-flow leaks repaired and 5 (3.6%) developed CSF leaks postoperatively. Of reported symptoms, rhinorrhea was most common (n = 52, 38.0%; PPV [95% CI] = 7.6% [4.8%, 11.9%]), followed by severe headache (n = 47, 34.3%; 6.3% [3.1%, 12.5%]), dizziness (n = 43, 31.4%; 2.3% [0.4%, 12.1%]), salty or metallic taste (n = 20, 14.6%; 9.9% [3.3%, 25.8%]), and throat drainage (n = 10, 7.3%; 9.9% [1.7%, 41.4%]). Nausea or vomiting constituted the most reported sign concerning for CSF leak (n = 73, 53.3%; PPV [95% CI] = 4.1% [2.0%, 8.1%]). On univariate regression, no sign or symptom, including rhinorrhea (OR [95% CI] = 7.00 [0.76-64.44]), throat drainage (3.42 [0.35-33.86]), salty/metallic taste (4.22 [0.66-27.04]), severe headache (3.00 [0.48-18.62]), dizziness (0.54 [0.06-4.94]), fever (3.16 [0.50-19.99]), and nausea/vomiting (1.33 [0.22-8.21]), associated with postoperative CSF leak.

CONCLUSIONS

A range of subjectively reported symptoms and signs failed to predict postoperative CSF leak. Further investigation is warranted to inform appropriate attention and response.

Chordoma: Genetics and Contemporary Management

Chordomas, arising from notochord remnants, are rare neoplasms with aggressive growth patterns despite their histologically low-grade nature. This review explores their embryological origins, molecular markers like brachyury, and genetic alterations driving pathogenesis. Diagnosis relies on advanced imaging and biopsy confirmation due to overlapping features with chondrosarcoma. The WHO classification distinguishes conventional, dedifferentiated, and poorly differentiated chordomas, each with distinct prognostic implications. Recent genomic analyses uncovered recurrent mutations in PI3K signaling pathways and chromatin remodeling genes, informing prognostic models. Surgery remains the cornerstone of treatment, though adjuvant radiation complements surgical resection. Although chordomas are generally considered refractory to medical therapy, emerging targeted molecular strategies show potential promise in ongoing trials. This review aims to provide a concise yet comprehensive overview of chordomas, guiding clinicians in diagnosis, treatment, and prognostication for improved patient outcomes.

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

BACKGROUND

The 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.

METHODS

A 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.

RESULTS

The 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.

CONCLUSIONS

The 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.

Learning Curve for Endoscopic Transsphenoidal Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Endoscopic transsphenoidal surgery (ETSS) is emerging as an effective, minimally invasive surgery technique for brain tumors of the pituitary fossa. Using a surgical endoscope, surgeons can obtain a broader, nearer, and more apparent visual field with minimal keyhole entrance. However, ETSS may require a steep learning curve to achieve technical competence and relevant outcomes. Moreover, there is no consensus on the learning process of ETSS. We aimed to review and determine the technical proficiency points of ETSS and discuss how to accelerate the learning curve.

METHODS

Core databases, including PubMed, Embase, and the Cochrane Library, were systematically searched for learning curve studies that demonstrated the clinical outcomes and learning status of ETSS for pituitary adenomas using numerical data. Quality assessments of the included articles were performed using the Newcastle-Ottawa scale. The cutoff points were evaluated based on various outcome measures.

RESULTS

Eleven full-text articles, representing 2780 cases, were selected from 317 screened studies. The outcome measures were operative time, tumor removal, endocrinological results, visual field, and surgical complications. The plateaus or cutoff points in the learning curve varied with a mean of 103 ± 139.43 (range, 9-500) cases.

CONCLUSIONS

ETSS is an efficient and minimally invasive alternative surgical option for pituitary tumors. Plateau points may differ according to outcome measures, patient selection, training status, and surgical conditions. Therefore, great care should be taken when interpreting the learning curve. A systematic training program is essential to improve the learning process of endoscopic neurosurgical procedures.

The learning curve for endoscopic endonasal pituitary surgery: a systematic review

Recent literature demonstrates that a learning curve exists for endoscopic pituitary surgery. However, there is significant variability in the way these studies report their outcomes. This study aims to systematically review the literature regarding outcomes for endoscopic pituitary surgery and how this may be related to a surgical learning curve. An electronic search of the databases Medline, Scopus, Embase, Web of Science and Cochrane Library databases was performed and data extracted according 2020 Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) statement. Ten articles were included in the review as they examined the following: rates of gross total resection, average operative time, CSF leak rate, visual outcomes, endocrine outcomes and how these results were influenced by surgical experience. We have demonstrated that a learning curve exists for some outcome variables for endoscopic pituitary surgery. However, there is significant heterogeneity in the current body of literature which makes clear comparisons difficult.

Remission, complications, and overall survival in transsphenoidal pituitary surgery-a Swedish single-center experience of 578 patients

BACKGROUND

Surgical treatment of pituitary lesions causing hormonal overproduction or mass effect is standard procedure. There are few reports on the results and complications related to these surgeries from Northern Europe. Our aim was to evaluate the outcome and complications of a single tertiary surgical center over more than a decade.

METHODS

This was a retrospective study on all patients that underwent pituitary surgery from 1st of January 2005 to 31st of December 2017. The analysis included type of lesion, surgical method, pre- and postoperative need for hormonal substitution, hormonal outcome, complications to surgery, survival, need for revision surgery, or stereotactic radiation. Appropriate statistical analyses were made to evaluate surgical results, complications, and survival.

RESULTS

Five hundred seventy-eight patients were included in the study. Remission was achieved in 58% of patients with GH-producing and 94% of ACTH-releasing adenomas. Sixty-six percent had no preoperative hormonal substitution compared to 39% postoperatively. Rhinosinusitis (10%) was the most commonly reported postoperative complication followed by leakage of cerebrospinal fluid (8%) and meningitis (4%). Standardized mortality rate for the study population was higher (p = 0.18) when compared to the general population.

CONCLUSION

Our results regarding remission rates and complications are in comparison with previous studies. Surgery of pituitary lesion can be considered a safe and efficient surgery. We noted lower rates of CSF leakage in the later part of the study period and believe that this, in part, was an effect by the introduction of a multidisciplinary surgical skull base team and increased surgical experience.

Tenets for the Proper Conduct and Use of Meta-Analyses: A Practical Guide for Neurosurgeons

Neurosurgeons today are inundated with rapidly amassing neurosurgical research publications. Systematic reviews and meta-analyses have consequently surged in popularity because, when executed properly, they constitute a high level of evidence and may save busy neurosurgeons many hours of combing and reviewing the literature for relevant articles. Meta-analysis refers to the quantitative (and discretionary) component of systematic reviews. It involves applying statistical techniques to combine effect sizes from multiple studies, which might offer more actionable insights than a systematic review without meta-analysis. Well-executed meta-analyses may prove instructive for clinical practice, but poorly conducted ones sow confusion and have the potential to cause harm. Unfortunately, recent audits have found the conduct and reporting of meta-analyses in neurosurgery (but also other surgical disciplines) to be relatively lackluster in methodologic rigor and compliance to established guidelines. Some of these deficiencies can be easily remedied through better awareness and adherence to prescribed standards-which will be reviewed in this article-but others stem from inherent problems with the source data (e.g., poor reporting of original research) as well as unique constraints faced by surgery as a field (e.g., lack of equipoise for randomized trials, or existence of learning curves for novel surgical procedures, which can lead to temporal heterogeneity), which may require unconventional tools (e.g., cumulative meta-analysis) to address. Therefore, it is also our goal to take stock of the unique issues encountered by surgeons who do meta-analysis and to highlight various techniques-some of which less well-known-to address such challenges.

Clinical relevance of tumor consistency in pituitary adenoma

PURPOSE

To review the clinical relevance of pituitary adenoma (PA) consistency and its relationship to clinical presentation, radiologic and histopathological characteristics, and surgical outcomes.

BACKGROUND

PA consistency is a critical factor influencing operative planning, surgical outcomes, and patient counseling. There is no validated classification of PA consistency in the literature, and there are no current preoperative variables capable of predicting it.

REVIEW

We conducted a thorough literature review of the Medline, Embase, Web of Science, and Cochrane Library databases. The inclusion criteria were all articles that described PA consistency and correlated it with preoperative aspects, radiological, pathological, and operative findings, or clinical outcomes.

DISCUSSION

Although most authors differentiate easily aspirated (soft) tumors from those that are not (fibrous, might require prior fragmentation), there is no universally accepted PA consistency classification. Fibrous PA tends to be hypointense on T2WI and has lower apparent diffusion coefficient (ADC) values. Fibrous tumors seemed to present higher invasion into neighboring structures, including the cavernous sinus. Several articles suggest that dopamine agonists could increase PA consistency and that prior surgery and radiotherapy also make PA more fibrous. The anatomopathological studies identify collagen as being mainly responsible for fibrous consistency of adenomas.

CONCLUSIONS

Preoperative knowledge of PA consistency affords the neurosurgeon substantial benefit, which clearly appears to be relevant to surgical planning, risks, and surgery outcomes. It could also encourage the centralization of these high complexity tumors in reference centers. Further studies may be enhanced by applying standard consistency classification of the PA and analyzing a more extensive and prospective series of fibrous PA.