Multicenter external validation of the Zurich Pituitary Score

Victor E. Staartjes, Carlo Serra, Matteo Zoli, Diego Mazzatenta, Fabio Pozzi, Davide Locatelli, Elena D’Avella, Domenico Solari, Luigi Maria Cavallo, Luca Regli

Research output: Contribution to journalArticlepeer-review


Purpose: Recently, the Zurich Pituitary Score (ZPS) has been proposed as a new quantitative preoperative classification scheme for predicting gross total resection (GTR), extent of resection (EOR), and residual tumor volume (RV) in endoscopic pituitary surgery. We evaluated the external validity of the ZPS. Methods: In three reference centers for pituitary surgery, the ZPS was applied and correlated to GTR, EOR, and RV. Furthermore, its inter-rater agreement was assessed. Results: A total of 485 patients (53% male; age, 53.8 ± 15.7) were included. ZPS grades I, II, III, and IV were observed in 110 (23%), 270 (56%), 64 (13%), and 41 (8%) patients, respectively. GTR was achieved in 358 (74%) cases, with mean EOR of 87.6% ± 20.3% and RV of 1.42 ± 2.80 cm3. With increasing ZPS grade, strongly significant decreasing trends for GTR (I, 92%; II, 77%; III, 67%; IV, 15%; p < 0.001) and EOR (I, 93.8%; II, 89.9%; III, 88.1%; IV, 75.4%; p < 0.001) were found. Similarly, RV increased steadily ([cm3] I, 0.16; II, 0.61; III, 2.01; IV, 3.84; p < 0.001). We observed intraclass correlation coefficients of 0.837 (95% CI, 0.804–0.865) for intercarotid distance and 0.964 (95% CI, 0.956–0.970) for adenoma diameter, and Cohen’s kappa of 0.972 (95% CI, 0.952–0.992) for the ZPS grades. Conclusions: Application of the ZPS in three external cohorts was successful. The ZPS generalized well in terms of GTR, EOR, and RV; demonstrated excellent inter-rater agreement; and can safely and effectively be applied as a quantitative classification of adenomas with relevance to surgical outcome.

Original languageEnglish
JournalActa Neurochirurgica
Publication statusE-pub ahead of print - Jan 1 2020


  • Extent of resection
  • External validation
  • Gross total resection
  • Outcome prediction
  • Pituitary adenoma
  • Zurich Pituitary Score

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology


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