gms | German Medical Science

Objective: Transsphenoidal surgery (TSS) is the treatment option of first choice for Cushing's disease (CD). The traditional microsurgical technique has recently been challenged by endoscopic surgical methods. We present endocrine outcome of TSS in CD with a modified contemporary microsurgical concept.

Method: 95 patients underwent TSS for newly-diagnosed CD (83 microadenomas and 12 macroadenomas). An enlarged resection was performed in 38 patients. A modified exploration technique with radial incisions was performed in 24 patients in whom an adenoma was not readily detectable. Inferior petrosal sinus sampling (IPSS) was performed in only 12 cases. Normal (or decreased) urinary cortisol and suppression below 2 µg/dL during a low-dose dexamethasone suppression test were required for endocrinological remission.

Results: An initial remission rate of 85.5% (71/83) was achieved in microadenomas. Six patients with microadenomas were re-operated for persistence and hypercortisolism was corrected in 5 of them. With re-operation included, the overall remission rate for microadenomas was 91.6%. In macroadenomas, a remission rate of 66.7% was achieved. No procedure-related complications occurred in primary surgery. Of the patients in remission, 75.6% had early postoperative random cortisol levels below 2 µg/dL, 15.4% had cortisol levels between 2 and 5 µg/dL, and 9% had cortisol levels >5 µg/dL. 15.2% of the patients with microadenomas developed postoperative partial hypopituitarism and 3% diabetes insipidus. No increased rate of hypopituitarism was found with enlarged adenomectomy compared to selective adenomectomy. Only a slightly higher rate of partial hypopituitarism (23.1%) was found if extensive exploration was required.

Conclusions: Transsphenoidal microsurgery is highly effective as initial therapy of CD. Early re-operation is a successful option if CD persists. If pituitary dependence has been established on the basis of endocrine functional testing, IPSS is not obligatory even if MRI is negative. Enlarged resection for poorly-demarcated microadenomas yields a high remission rate without compromising pituitary function.