Visual Dysfunction in Nonfunctioning Pituitary Adenomas
Visual Dysfunction in Nonfunctioning Pituitary Adenomas
Background Despite ample experience with surgical treatment of nonfunctioning pituitary adenomas, objective data defining the risk for visual compromise depending on the suprasellar extension in pituitary adenomas are sparse.
Design and patients We measured the suprasellar extension of 98 newly diagnosed suprasellar nonfunctioning pituitary adenomas on sagittal and coronal magnetic resonance images using reference lines for the skull base level. In addition, the position of the optic chiasm in relation to the suprasellar adenoma was assessed. The findings were correlated with the degree of visual dysfunction and with the type of visual field defects (VFD).
Results Seventy per cent of the patients suffered from VFD. The most frequent perimetric findings were bilateral (81·2%) or unilateral (10·1%) temporal hemifield defects. For the coronal view, a suprasellar extension of 12 mm was a practicable cut-off value for emergence of visual disturbances (87·0% sensitivity, 72·4% specificity). For the sagittal view, 8-mm suprasellar extension was a suitable cut-off for appearance of chiasma syndrome (87·0% sensitivity, 75·9% specificity). In five of seven cases without a chiasma syndrome despite a suprasellar extension >12 (coronal) and 8 mm (sagittal), the optic chiasm was found in an anterior position. No correlation was found between the position of the chiasm (i.e. anterior, superior or posterior) and the type of VFD (P = 0·647). A highly significant correlation was found between the decline of visual acuity and the suprasellar adenoma extension (P < 0·0001).
Conclusion Cut-off values possess a high sensitivity and specificity for imminent visual disturbances and are helpful for clinical decision-making. A delayed emergence of visual dysfunction may be observed with an anterior position of the optic chiasm.
Nonfunctioning pituitary adenomas are usually large at the time of diagnosis, commonly presenting with visual field defects (VFD), headaches and hypopituitarism. Nonfunctioning pituitary adenomas are most frequently encountered among the pathologies that cause compression of the optic chiasm. In contrast, functioning pituitary adenomas are predominantly diagnosed because of hormonal hypersecretion before chiasma compression occurs. In addition to pituitary adenomas, other less-frequent diseases, such as craniopharyngiomas or perisellar meningiomas, can also cause a chiasma syndrome. Bitemporal VFD from compression of the optic chiasm by a sellar lesion are the most frequent neuro-opthalmic manifestation.
Transsphenoidal surgery is the approach of choice for over 90% of pituitary tumours and can decompress the neighbouring structures. Relief of the optic chiasm mostly results in regression of chiasma syndrome. In addition, decompression of the pituitary gland and stalk can improve pituitary function in a substantial number of patients. The indication for surgical therapy of pituitary adenomas depends on the symptoms, on the size of the adenoma and on the direction of growth. Visual deterioration is a major threat for the patients and necessitates neurosurgical decompression of the optic chiasma and removal of the tumour. Visual fields can be plotted accurately with Goldmann kinetic perimetry as well as automated static perimetry. High resolution magnetic resonance imaging (MRI) can demonstrate the accurate position of the optic chiasm and its displacement by the tumour.
Despite ample experience with surgical treatment of pituitary adenomas, data that define the risk for visual compromise depending on morphological tumour characteristics as assessed by MRI are sparse. To define objective criteria for the risk of visual compromise, we have correlated the size of suprasellar extension with ophthalmological findings in a series of 98 consecutive patients scheduled for surgical treatment of nonfunctioning pituitary adenomas with suprasellar extension. The position of the optic chiasm in the chiasmatic cistern is variable and is described to be prefixed or postfixed. On the other hand, the suprasellar growth in pituitary adenomas can be directed presellar, straight upward or retrosellar. Hence, we have additionally assessed the position of the chiasma in relation to the suprasellar adenoma and the resulting VFD.
Knowledge of criteria predicting visual compromise in pituitary adenomas will help in clinical decision-making and influences neurosurgical management of pituitary adenomas.
Abstract and Introduction
Abstract
Background Despite ample experience with surgical treatment of nonfunctioning pituitary adenomas, objective data defining the risk for visual compromise depending on the suprasellar extension in pituitary adenomas are sparse.
Design and patients We measured the suprasellar extension of 98 newly diagnosed suprasellar nonfunctioning pituitary adenomas on sagittal and coronal magnetic resonance images using reference lines for the skull base level. In addition, the position of the optic chiasm in relation to the suprasellar adenoma was assessed. The findings were correlated with the degree of visual dysfunction and with the type of visual field defects (VFD).
Results Seventy per cent of the patients suffered from VFD. The most frequent perimetric findings were bilateral (81·2%) or unilateral (10·1%) temporal hemifield defects. For the coronal view, a suprasellar extension of 12 mm was a practicable cut-off value for emergence of visual disturbances (87·0% sensitivity, 72·4% specificity). For the sagittal view, 8-mm suprasellar extension was a suitable cut-off for appearance of chiasma syndrome (87·0% sensitivity, 75·9% specificity). In five of seven cases without a chiasma syndrome despite a suprasellar extension >12 (coronal) and 8 mm (sagittal), the optic chiasm was found in an anterior position. No correlation was found between the position of the chiasm (i.e. anterior, superior or posterior) and the type of VFD (P = 0·647). A highly significant correlation was found between the decline of visual acuity and the suprasellar adenoma extension (P < 0·0001).
Conclusion Cut-off values possess a high sensitivity and specificity for imminent visual disturbances and are helpful for clinical decision-making. A delayed emergence of visual dysfunction may be observed with an anterior position of the optic chiasm.
Introduction
Nonfunctioning pituitary adenomas are usually large at the time of diagnosis, commonly presenting with visual field defects (VFD), headaches and hypopituitarism. Nonfunctioning pituitary adenomas are most frequently encountered among the pathologies that cause compression of the optic chiasm. In contrast, functioning pituitary adenomas are predominantly diagnosed because of hormonal hypersecretion before chiasma compression occurs. In addition to pituitary adenomas, other less-frequent diseases, such as craniopharyngiomas or perisellar meningiomas, can also cause a chiasma syndrome. Bitemporal VFD from compression of the optic chiasm by a sellar lesion are the most frequent neuro-opthalmic manifestation.
Transsphenoidal surgery is the approach of choice for over 90% of pituitary tumours and can decompress the neighbouring structures. Relief of the optic chiasm mostly results in regression of chiasma syndrome. In addition, decompression of the pituitary gland and stalk can improve pituitary function in a substantial number of patients. The indication for surgical therapy of pituitary adenomas depends on the symptoms, on the size of the adenoma and on the direction of growth. Visual deterioration is a major threat for the patients and necessitates neurosurgical decompression of the optic chiasma and removal of the tumour. Visual fields can be plotted accurately with Goldmann kinetic perimetry as well as automated static perimetry. High resolution magnetic resonance imaging (MRI) can demonstrate the accurate position of the optic chiasm and its displacement by the tumour.
Despite ample experience with surgical treatment of pituitary adenomas, data that define the risk for visual compromise depending on morphological tumour characteristics as assessed by MRI are sparse. To define objective criteria for the risk of visual compromise, we have correlated the size of suprasellar extension with ophthalmological findings in a series of 98 consecutive patients scheduled for surgical treatment of nonfunctioning pituitary adenomas with suprasellar extension. The position of the optic chiasm in the chiasmatic cistern is variable and is described to be prefixed or postfixed. On the other hand, the suprasellar growth in pituitary adenomas can be directed presellar, straight upward or retrosellar. Hence, we have additionally assessed the position of the chiasma in relation to the suprasellar adenoma and the resulting VFD.
Knowledge of criteria predicting visual compromise in pituitary adenomas will help in clinical decision-making and influences neurosurgical management of pituitary adenomas.