Year : 1995 | Volume
: 43 | Issue : 3 | Page : 131--134
Visual status in suprasellar pituitary tumours
Apjit Kaur1, Deepu Banerji2, Devendra Kumar2, Kartikey Sharma2,
1 Neuro-ophthalmology Unit, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raibareily Road, Lucknow 226 014, India
2 Department of Neurosurgery Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raibareily Road, Lucknow 226 014, India
Neuro-ophthalmology Unit, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raibareily Road, Lucknow 226 014
A retrospective analysis of 29 cases of pituitary tumours with suprasellar extension that had undergone surgery by transsphenoidal or transcranial route, was done. The correlation between age, duration of symptoms, pre-and postoperative visual acuity, visual field and suprasellar height of the tumour were analyzed. The age and duration of visual loss were found to have a bearing on the final postoperative visual outcome.
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Kaur A, Banerji D, Kumar D, Sharma K. Visual status in suprasellar pituitary tumours.Indian J Ophthalmol 1995;43:131-134
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Kaur A, Banerji D, Kumar D, Sharma K. Visual status in suprasellar pituitary tumours. Indian J Ophthalmol [serial online] 1995 [cited 2022 Sep 29 ];43:131-134
Available from: https://www.ijo.in/text.asp?1995/43/3/131/25286
Pituitary adenomas comprise about 10% of intracranial tumours. Clinically, they present either as secretory or non-secretory adenomas. Visual manifestations are more common in non-secretory tumours. Approximately, 70% of pituitary adenomas present with visual manifestations in the form of diminished acuity and/or field defects. The age, duration of symptoms, preoperative visual acuity and height of tumour have a bearing on the postoperative visual improvement.
We undertook a retrospective analysis of 29 cases of pituitary adenomas with visual involvement to study the effect of these factors on the final postoperative visual outcome.
MATERIALS AND METHODS
This study was conducted over a period of two years from June 1991 to June 1993 on 29 out of 79 patients of pituitary tumours operated at Sanjay Gandhi Post Graduate Institute of Medical Sciences. There were 16 males and 13 females. The age ranged from 12 to 60 years. All of them had visual loss with suprasellar extension and were followed up postoperatively for a mean period of 11 months (range, 6 to 24 months).
Each patient was subjected to detailed history, clinical examination including evaluation of neuro-ophthalmologic, neurological and endocrinal status preoperatively and postoperatively at 1 week, 6 weeks and 6 months. Neuro-ophthalmologic examination included visual acuity, fundus and visual field. The Topcon computerised perimeter was usually used for field examination and in cases of poor cooperation, Goldmann perimeter was used. Computerized tomography (CT) scan was repeated at 6 weeks follow-up to look for residual tumour and thereafter on clinical or endocrinological suspicion of recurrence.
The patients were grouped on the basis of duration of visual disturbances into four groups of six months duration each [Table:1]. Visual acuity in the worst eye was considered for preoperative division of the patients into three groups. Group I included patients with visual acuity 6/5 to 6/12, group II included patients with visual acuity 6/18 to 6/36 and group III included patients with visual acuity 6/60 to no vision [Table:2].
Based on the visual field defects, the patients were also divided into three groups, i.e., A, B and C [Table:3]. Group A included patients with normal visual field. Group B included typical field defects, which was further subdivided into (i) quadrantanopia, unilateral or bilateral (ii) hemianopia, unilateral or bilateral and (iii) three quadrant or more field loss, unilateral or bilateral. Group C included atypical field defects (defined as the defect that does not correspond to any characteristic pattern of defect according to the site of involvement, despite the presence of such lesion).
The suprasellar extension of pituitary tumour was assessed radiologically based on CT scan measurement of tumour height above the tuberculum sellae in coronal cuts. The patients were divided into three groups on the basis of suprasellar extension of tumour [Table:4]. Group I included tumour height upto 1 cm or obliteration of suprasellar cisterns. Group II included tumour height upto 2 cm or obliteration of anterior third ventricular recess. Group III included tumour height more than 2 cm or obliteration of third ventricle.
On the basis of suprasellar or parasellar extension, the patients were operated either by transcranial or transsphenoidal route. Significant parasellar extension and basi-frontal extension required transcranial surgery in 13 cases.
Of a total of 29 patients, 16 were male and 13 were female. The age ranged from 12 to 60 years. Maximum number of patients (13) were in the age range of 31 to 45 years [Table:5]. Our study included 26 non-functioning adenomas, and 3 functioning pituitary tumours. Among 26 non-functioning adenomas, 23 were chromophobe adenomas. Duration of symptoms varied between three days and 24 months. Most of the patients (16 out of 29) reported within six months and showed maximum improvement in visual acuity postoperatively. With longer duration of symptoms visual recovery was less [Table:1].
Majority of patients (19/29) had grossly diminished preoperative visual acuity [Table:2]. Postoperatively, improvement in visual acuity occurred in 73.6% of patients of group III, while only 42.2% of patients of group II showed improvement. Four patients had deterioration of vision post-operatively. Visual acuity deteriorated in one of the 19 patients of group III (5.2%) and in 3 of the 7 patients of group II (42.8%).
None of the patients had normal field [Table:3]. Bitemporal hemianopia, seen in 18 patients, (62%) was the most commonly encountered field defect. Quadrantanopia was seen in two patients and three quadrant or more field loss, either uniocular or binocular, was seen in five patients. Postoperatively, quadrantanopia improved completely, whereas only two patients out of five (40%) with three quadrant or more field loss, showed improvement postoperatively. Typical hemianopic field defects improved in seven out of eighteen patients (38.8%) after surgery. Atypical field defects were charted in four patients (13.7%) and only one of them showed improvement postoperatively.
Correlation of visual acuity and suprasellar extension is shown in [Table:4]. Five patients had grade I tumour, 15 had grade II tumour and 9 patients had grade III tumour extension. The degree of visual loss was highest in grade III tumour (88.9% of cases with group III visual acuity loss), followed by 73.3% of cases with group III visual acuity in grade II tumour. In 3 patients of grade II and one patient of grade I tumour, there was deterioration of vision following surgery.
Visual disturbances in pituitary tumours is a common presentation. Although the incidence of visual loss as a presenting feature has markedly decreased due to the advances in radiological techniques and the availability of hormonal assays, there are many reports in the literature in regard to the visual symptoms and signs of pituitary tumour.,,, In our study, the analysis has been based on observations made in context with pituitary tumours with suprasellar extension.
Miller et al in their study of 33 patients observed that increasing age has a bearing on the final visual outcome, when all other parameters, such as type and size of tumour, and duration of symptoms are matched. Although in our study these parameters have not been matched, there appears to be a decrease in the number of cases that improved postoperatively as the age of the patients advanced. This could be due to decreased capability of neuronal regeneration with advancing age.
The duration of visual symptoms has a reciprocal relationship to the degree of improvement, irrespective of the degree of visual loss. [Table:1] shows that patients who had less than six months of symptoms showed maximum improvement. This group included four patients who had gross visual loss associated with apoplexy. Apoplexy causes a sudden increase in the size of tumour causing damage to the intracranial visual pathway. The defects produced depend on the location of tumour, whether pre-chiasmatic, directly below chiasma or post chiasmatic. A pre-chiasmatic lesion extending laterally would cause involvement of optic nerve ipsilaterally. Ischemic damage may occur in isolation or along with compression. Compressive damage to optic pathway is likely to improve more after surgical decompression as compared to ischemic damage. The loss is usually bilateral. We had two patients with unilateral and two with bilateral visual loss.
As this study included only those patients who had visual symptoms due to suprasellar extension, there were no patients with normal visual acuity. Maximum number of patients (65.5%) had severe loss of visual acuity. The direction of growth of tumour and/or position of the tumour in relation to the visual pathway determines uniocular or binocular visual loss. We had five patients with uniocular involvement, where the tumour extended more towards one side causing direct compression of the optic nerve ipsilaterally. Visual loss is not commonly associated with functional pituitary tumours because they present earlier with symptoms of pituitary hyperfunction We, however, encountered three acromegalics with visual loss due to large pituitary adenomas. The reason for such a phenomenon is ignorance and late reporting in our social setup.
Bitemporal hemianopia is considered the "hallmark" of pituitary tumours due to chiasmal compression from below., In our study too, this was the most commonly encountered field defect [Table:3]. Atypical field defects encountered were peripheral constriction and central scotoma but these defects are of rare occurrence. In our study, early and incomplete relative field defects showed improvement. These included quadrantanopia and relative hemianopias. Trautman et al noted that visual fields were affected more frequently than visual acuity. However, due to the selective inclusion of patients in our study, no such association was seen.
The suprasellar extension and size of tumour had a direct relationship with visual loss. Large tumours included maximum number of patients with severe visual loss. The postoperative visual outcome did not show a direct correlation with the tumour size as 7 out of 9 patients of grade III showed improvement [Table:4]. The final visual outcome appears to have a greater dependence on duration of symptoms than on the size of tumours. Non-secretory tumours are known to attain large sizes before becoming symptomatic.
Of the 4 patients that deteriorated postoperatively, one was operated by transcranial and the remaining 3 by transsphenoidal route. Visual loss after transcranial surgery was possibly due to peroperative trauma to the optic nerve. One of the 3 patients who underwent transsphenoidal surgery had only minimum postoperative visual deterioration. No satisfactory reason could be ascertained for the other two patients. Loss of vision has been reported after transsphenoidal surgery. This could be due to direct traction injury in such cases.
It is clear from this study that the age, duration of symptoms, preoperative visual loss, type of tumour and suprasellar height of the tumour are important parameters in the evaluation of cases of pituitary tumour. Though the number of cases in this study is small to derive a statistically significant conclusion, the age of the patient and duration of visual symptoms were the most important factors determining the postoperative improvement of vision.
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