Elsevier

World Neurosurgery

Volume 109, January 2018, Pages e409-e416
World Neurosurgery

Original Article
Endoscopic Transsphenoidal Surgery Outcomes in 331 Nonfunctioning Pituitary Adenoma Cases After a Single Surgeon Learning Curve

https://doi.org/10.1016/j.wneu.2017.09.194Get rights and content

Objective

The outcomes of recent endoscopic surgery of nonfunctioning pituitary adenomas (NFPAs) are controversial when compared with traditional microscopic surgery. We aimed to assess the outcomes of endoscopic transsphenoidal surgeries performed by 1 surgeon with 7 years of experience and elucidate the predictive factors for surgical outcomes for NFPAs.

Methods

We included 331 patients (155 men and 176 women) with clinical NFPAs who underwent transsphenoidal surgery because of visual symptoms by a single surgeon in Seoul National University Hospital from March 2010 to May 2016. We assessed the tumor removal rate, hormonal outcomes, visual outcomes, and complications.

Results

The gross total resection rate of endoscopic transsphenoidal surgery for NFPAs by a single surgeon was 74.9%. Cavernous sinus invasion, a high Knosp grade, large tumor size, previous surgery, and lack of surgical experience in the neurosurgeon elevated the risk for residual tumors. Visual deficits were improved in 73.4% of the patients, which was associated with tumor size, preoperative visual impairment score, previous radiation, and surgical experience. Hormonal status was improved in 15.4% and aggravated in 32.9% after surgery. There were no predictors for hormonal recovery. Transient diabetes insipidus (DI) was the most common complication (9.1%), and among these patients, 3.0% had persistent DI.

Conclusions

Endoscopic transsphenoidal surgery by a well-experienced surgeon was an effective and safe treatment for NFPAs, but the hormonal outcomes were not changed compared with previous reports of microscopic surgery. Large tumor size and cavernous sinus invasion were still the barriers for achieving total resection.

Introduction

Pituitary adenomas (PAs) are the second most common brain tumors, and the prevalence is approximately 1 in 1000 in community-dwelling adults.1 PAs can be manifested as hormone secretion or mass effects. Among PAs, nonfunctioning pituitary adenomas (NFPAs) account for 14%–54%.1, 2 In NFPAs, visual symptoms is the definite surgical indication, and hypopituitarism is not an absolute surgical indication.2 The surgical removal of NFPAs does not guarantee the recovery from hormone deficiency. In addition, several reports have demonstrated that transsphenoidal surgery also carries the risk of hypopituitarism and hormonal recovery simultaneously.3, 4 However, transsphenoidal surgery for NFPAs is challenging because the tumor sizes are large, and suprasellar extension and cavernous sinus invasion are common.5, 6, 7 One critical factor for various outcomes of endoscopic surgery may be the surgeon's skills and experiences.5, 8

Microscopic transsphenoidal surgery is the traditional surgical technique. Twenty years ago, endoscopic techniques were introduced into transsphenoidal pituitary surgeries.9, 10 Compared with microscopy, the wide view of endoscopy improves the visualization of the suprasellar and lateral extension of tumors and differentiation of tumors from normal glands and surrounding tissues.11, 12 Theoretically, the wider visualization of endoscopic surgery might provide a higher gross total resection (GTR) rate and a lower complication rate. However, whether endoscopic surgery is better than microscopic surgery in terms of surgical outcomes and complications has been controversial.13, 14 For NFPAs, the GTR rate of endoscopic surgery has been reported to vary from 59% to 92%,5, 6, 7, 10, 12, 15 which appeared similar to the results for microscopic surgery (50%–83%).14, 16

Herein, we aim to assess the outcomes of endoscopic transsphenoidal surgery in terms of tumor resection, visual outcomes, and hormone outcomes after 1 surgeon's experiences over 7 years and to elucidate the predictive factors for surgical outcomes for NFPAs.

Section snippets

Study Population

The study was approved by the Institutional Review Board of Seoul National University Hospital (number 1503-040-654). We reviewed 331 patients (155 men and 176 women) with clinical NFPAs who underwent transsphenoidal surgery because of visual symptoms by a single surgeon in Seoul National University Hospital from March 2010 to May 2016. We excluded pituitary apoplexy cases. All patients were followed-up at a postoperative visit 3 months after surgery and were assessed by an endocrinologist and

Results

Baseline characteristics of study subjects are shown in Table 1. The median age was 53.0 years, and median body mass index was 24.9 kg/m2. Of 331 patients, 97 patients had a history of previous surgery and 15 patients received gamma-knife surgery or radiation previously. Only 2 cases were microadenomas, and 46 cases (13.9%) were giant adenomas >4 cm. Cavernous sinus invasion (Knosp grade ≥3) was identified in 144 cases (43.5%). Preoperative visual assessment data were available in 322 patients,

Discussion

In this study, the success rate of endoscopic transsphenoidal surgery for NFPAs by a single surgeon was 74.9% and was affected by cavernous sinus invasion, tumor size, previous history of surgery, and surgical experiences. Overall, hormonal outcomes were not improved by endoscopic transsphenoidal surgery. Visual outcomes were improved in 73.4% of all patients, and favorable outcomes were expected in those with smaller adenomas, no history of previous surgery or radiation, and in whom the

Acknowledgments

We thank all colleagues who contributed to the study.

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    Conflict of interest statement: This study was supported by a grant (HI16C-1111-020016; to Y. H. K.) from the Korea Health Industry Development Institute.

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