Intraoperative High-Field Magnetic Resonance Imaging in Transsphenoidal Surgery of Hormonally Inactivepituitary Macroadenomas

Gamma knife radiosurgery for patients with nonfunctioning pituitary adenomas: results from a 15-year experience

PURPOSE

To evaluate the efficacy and complications of stereotactic radiosurgery for patients with nonfunctioning pituitary adenomas (NFA).

METHODS AND MATERIALS

This was a retrospective review of 62 patients with NFA undergoing radiosurgery between 1992 and 2004, of whom 59 (95%) underwent prior tumor resection. The median treatment volume was 4.0 cm(3) (range, 0.8-12.9). The median treatment dose to the tumor margin was 16 Gy (range, 11-20). The median maximum point dose to the optic apparatus was 9.5 Gy (range, 5.0-12.6). The median follow-up period after radiosurgery was 64 months (range, 23-161).

RESULTS

Tumor size decreased for 37 patients (60%) and remained unchanged for 23 patients (37%). Two patients (3%) had tumor growth outside the prescribed treatment volume and required additional treatment (fractionated radiation therapy, n = 1; repeat radiosurgery, n = 1). Tumor growth control was 95% at 3 and 7 years after radiosurgery. Eleven (27%) of 41 patients with normal (n = 30) or partial (n = 11) anterior pituitary function before radiosurgery developed new deficits at a median of 24 months after radiosurgery. The risk of developing new anterior pituitary deficits at 5 years was 32%. The 5-year risk of developing new anterior pituitary deficits was 18% for patients with a tumor volume of < or = 4.0 cm(3) compared with 58% for patients with a tumor volume >4.0 cm(3) (risk ratio = 4.5; 95% confidence interval = 1.3-14.9, p = 0.02). No patient had a decline in visual function.

CONCLUSIONS

Stereotactic radiosurgery is effective in the management of patients with residual or recurrent NFA, although longer follow-up is needed to evaluate long-term outcomes. The primary complication is hypopituitarism, and the risk of developing new anterior pituitary deficits correlates with the size of the irradiated tumor.

Image-guided surgery of liver metastases by three-dimensional ultrasound-based optoelectronic navigation

BACKGROUND

Vessel-oriented surgery and tumour-free resection margins are essential for resection of liver metastases to preserve liver parenchyma and improve oncological outcome. Preoperative three-dimensional models reconstructed from imaging data could facilitate surgical planning with the use of navigation technology.

METHODS

Thirty-three patients with central and/or impalpable liver metastases were scheduled for navigated hepatic resection. Intraoperative three-dimensional ultrasonography and an infrared-based optical tracking system were used for data registration and image-guided surgery. Postoperative three-dimensional data were compared with the preoperative virtual surgical plan to assess the accuracy of navigation, and clinical results were compared with those of a matched control group of 32 patients.

RESULTS

Navigation was successful in 32 of 33 patients. Realization of the preoperative plan and R0 resection was achieved in 30 of these 32 patients. The median discrepancy between the planned and actual vascular dissection level was 6 (range 0-11) mm. There was a reduced rate of R1 resection in the navigated group compared with the control group (two versus four patients), and more parenchyma was preserved.

CONCLUSION

Three-dimensional ultrasound-based optoelectronic navigation technology improves intraoperative orientation and enables parenchyma-preserving surgery with high precision.

Surgical treatment of nonfunctioning pituitary adenomas

Small nonfunctioning pituitary (micro)adenomas are encountered frequently as incidental findings. Large (macro)adenomas present with visual compromise, hypopituitarism or headache. Indications for surgery include loss of vision, diplopia, other symptoms of a space occupying intracranial lesion and documented tumor progression during serial imaging. Their primary treatment is surgical resection. To exclude medical treatment options, a preoperative endocrinological investigation is mandatory. To date, more than 90% of operations in patients with nonfunctioning pituitary adenomas are performed via the transsphenoidal route. There are several variations of transnasal surgery available, with and without dissection of the nasal septum. Only tumors where the predominant mass lesion is essentially located outside the sella require transcranial operations. These are usually performed via a frontotemporal or frontolateral craniotomy. Surgical decompression of visual pathways is usually followed by a rapid improvement of vision. Whether or not the tumor mass can be completely resected depends on the size and localization of the adenoma and the surgical expertise. Several patients experience an improvement of pituitary function. Potential complications of surgery include loss of vision, vascular injury, cerebrospinal fluid fistula, meningitis and hypopituitarism. Modern technical developments, such as the use of the endoscope, intraoperative magnetic resonance imaging and neuronavigation, are being increasingly appreciated by neurosurgeons throughout the world.