|Year : 2015 | Volume
| Issue : 3 | Page : 212-215
Postoperative visual field outcome measured by perimetry in sellar and parasellar tumors
Ahmed M Ali Mahmoud BSc, MSc, MD 1, Shaymaa H Salah2
1 Department of Neurosurgery, Kasr Al-Ainy Medical School, Cairo University, Giza, Egypt
2 Department of Ophthalmology, Cairo University, Giza, Egypt
|Date of Submission||23-Jan-2015|
|Date of Acceptance||01-Mar-2015|
|Date of Web Publication||13-Aug-2015|
Ahmed M Ali Mahmoud
Department of Neurosurgery, Kasr Al-Ainy Medical School, Cairo University, Giza
Source of Support: None, Conflict of Interest: None
Compressive optic neuropathy at chiasm may lead to different degrees of visual acuity affection, color vision loss, and visual field (VF) changes in both eyes.
This study evaluates the predictive value of VF outcome 3 months after treatment of chiasmal and parachiasmal tumor compressing the anterior visual pathways.
Fifteen patients (eight women and seven men) were included in this study; their ages ranged from 30 to 57 years. All patients were operated upon at the Kasr El-Aini Neurosurgical Department. All of them underwent an evaluation of their history, a clinical examination, standard automated perimetry, evaluation of their hormonal profile, and radiological investigations. Ten patients were operated upon by means of the microscopic-assisted endoscopic endonasal trans-sphenoidal approach, and the remaining five patients were operated upon transcranially.
Best-corrected visual acuity showed significant improvement from 0.464 ± 0.367 to 0.16 ± 0.17 LogMAR (P = 0.009) in all patients after surgery. Mean deviation showed improvement in all patients, which was not statistically significant, from −11.289 ± 9.952 dB before surgery to −8.578 ± 7.651 dB at 3 months after surgery (P = 0.330). As regards temporal VF sensitivity, group 1 showed significant improvement in temporal field sensitivity, from 88.054 to 237.967 1/Lambert (l/L), whereas group 2 showed significant worsening in temporal sensitivity, from 198.272 to 100.764 (l/L), and group 3 showed improvement in temporal sensitivity from 702.97 to 820.568 (l/L).
In this series, temporal field sensitivity was the best prognostic factor for determining the VF outcome in decompression surgery for sellar and parasellar tumors.
Keywords: parasellar tumors, perimetry, visual field
|How to cite this article:|
Ali Mahmoud AM, Salah SH. Postoperative visual field outcome measured by perimetry in sellar and parasellar tumors. Egypt J Neurol Psychiatry Neurosurg 2015;52:212-5
|How to cite this URL:|
Ali Mahmoud AM, Salah SH. Postoperative visual field outcome measured by perimetry in sellar and parasellar tumors. Egypt J Neurol Psychiatry Neurosurg [serial online] 2015 [cited 2021 Apr 21];52:212-5. Available from: http://www.ejnpn.eg.net/text.asp?2015/52/3/212/162049
| Introduction|| |
Areas of the sellar and parasellar region have anatomical boundaries that extend from the basisphenoid sinus below, laterally to the cavernous sinus, with suprasellar extension to ventricular walls . These anatomical landmarks harbor many vital structures such as pituitary gland, its stalk, the hypothalamus, optic apparatus, anterior vascular circulation, and contents of cavernous sinus cranial nerves of eye movement, venous network, and the third part of the carotid artery . Lesions in that area can arise from meninges, pituitary gland, vascular tree, optical apparatus, and extension from below, such as nasopharyngeal neoplasm, or from above, such as ventricular tumors ,. Many types of tumors arise in that critical area, such as pituitary adenoma, carcinoma, craniopharyngioma, optic gliomas, meningiomas, germ cell tumors, and vascular lesions like aneurysms and carotid-cavernous fistula . Tumors in these areas give rise to many clinical symptoms such as headache, hormonal imbalance, cranial nerve dysfunction, and visual impairment .
MRI is the test of choice for diagnosing these lesions. With the aid of computed tomography (CT) and CT angiography it can outline bony invasion and the relationship between lesions and the vascular tree in these areas. Hormonal assay is very crucial for initiating therapy if needed, and the patient has to undergo perimetry and clinical assessment for visual functions ,.
Lesions in these areas lead to a compressive effect on the visual apparatus, which gives rise to many degrees of visual acuity (VA) and visual field (VF) affection. The mechanism of injury may be due to direct compression or axonoplasmic affection . Postoperative clinical improvement depends on the structural and functional status of the visual apparatus preoperatively and postoperatively ,.
This study aims to evaluate the postoperative VF outcome in patients with sellar and parasellar tumors and the impact of surgery on postoperative VF prognosis.
| Patients and methods|| |
Fifteen patients with sellar and parasellar tumors (eight women and seven men) were included in this study. Their ages ranged from 30 to 57 years. All patients were operated upon at the Kasr El-Aini Neurosurgical Department from June 2013 to February 2014. All of them underwent an evaluation of their history, a clinical examination, perimetry, evaluation of their hormonal profile, and radiological investigations in the form of CT scan, MRI, and four-vessel angiography when needed to outline the relation between tumors and the vascular tree. None of the patients had local eye disease. Ten patients were operated upon by means of the microscopic-assisted endoscopic endonasal trans-sphenoidal approach for better visualization of the optic apparatus. The remaining five patients were operated upon transcranially by means of the pterional approach. All patients underwent a postoperative CT scan, hormonal assay, and assessment of VF, using perimetry, within 1 week and at 3 months. Thirteen patients were discharged within 7 days after operation. Two patients had diabetes insipidus and had to remain hospitalized for 3 more days.
All patients had an uneventful surgery without major complications. Chiasma was prefixed in seven cases and postfixed in eight cases. Seven cases were pituitary adenoma, four cases were craniopharyngioma, and four cases were meningioma; 13 patients underwent gross total excision, and in the other two cases the tumor was attached to the anterior communicating artery. A small residual tumor not more than 1.5 cm 3 was left attached to it.
Perimetry was performed in both eyes and the eye with the lesser VF defect of each patient was selected for analysis. An unreliable VF testing (>30% false positive, false negative, or fixation loss; a spherical refractive error outside the range of -5 diopters) was excluded. Standard automated perimetry was conducted using the Swedish Interactive Threshold Algorithm (SITA) 24-2 of the Humphrey Field Analyzer program (Carl Zeiss Meditec AG, Jena, Germany) with a Goldmann size III stimulus on a 31.5-apostilb background. The cluster criterion for an abnormal hemifield (split into temporal and nasal hemifields) was three or more significantly depressed (P < 5%) non-edge-contiguous points on the PD plot, with two of these points having a P-value less than 2%, not including those directly above and below the blind spot. Eyes were divided into three groups based on the initial VF defect and its evolution: group 1 had an initial VF defect that incompletely resolved 3 months after surgery; group 2 had a VF defect that worsened 3 months after surgery; and group 3 had an initial VF defect that completely resolved 3 months after surgery [Table 1].
Microsoft excel 2010 was used for data entry and the statistical package for social science (version 21) (IBM, New York, United State) was used for data analysis. Simple descriptive statistics (arithmetic mean and SD) were used for summary of quantitative data, and frequencies were used for qualitative data. The independent t-test was used to compare normally distributed quantitative data, whereas the Mann-Whitney test was used to compare non-normally distributed quantitative data. Nonparametric Spearman's correlation was used to compare non-normally distributed quantitative data, and P-value less than 0.05 was considered statistically significant.
| Results|| |
Best-corrected VA showed significant improvement from 0.464 ± 0.367 to 0.16 ± 0.17 LogMAR (P = 0.009) in all patients after surgery. Group 3 showed the most statistically significant improvement in VA. Mean deviation (MD) showed improvement in all patients, which was not statistically significant, from −11.289 ± 9.952 dB before surgery to -8.578 ± 7.651 dB at 3 months after surgery (P = 0.33). Group 1 showed statistically significant improvement in MD, whereas group 2 showed statistically significant deterioration in MD.
As regards temporal VF sensitivity, Group 1 showed significant improvement from 88.054 to 237.967 1/Lambert (l/L), whereas group 2 showed significant worsening in temporal sensitivity from 198.272 to 100.764 (l/L) and group 3 showed improvement in temporal sensitivity from 702.97 to 820.568 (l/L). In both groups 1 and 2 no correlations were found postoperatively between best-corrected VA and MD, nor with temporal sensitivity (P > 0.05), whereas moderate correlation was found in group 3 (P < 0.05, r = 0.5-0.7) [Table 2].
|Table 2: Visual field parameters in each group preoperatively and postoperatively|
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| Discussion|| |
In this study, patients were divided into three groups based on their initial VF defect and its evolution. Group 1 had an initial VF defect that incompletely resolved 3 months after surgery (seven cases were totally excised); group 2 had a VF defect that worsened 3 months after surgery (three patients; 1 underwent total excision and the other two underwent subtotal excision); group 3 had an initial VF defect that completely resolved 3 months after surgery (five cases were totally excised). Thus, 13 patients underwent total excision (86.6%) and two cases underwent subtotal excision (13.4%).
There are many factors that can affect visual outcome. These factors include longstanding compression of the optic pathway, intraoperative complications, preoperative degree of field changes, and obstruction of blood supply to the visual pathway. This study evaluates the different changes in the VF as a predictive value of VF outcome 3 months after treatment of parachiasmal tumors compressing the anterior visual pathways. VF was used rather than VA, as VA reflects the function of a small area of the VF, whereas the quantitative VF defect better reflects the effect of compression onto the anterior visual pathways. In addition, the majority of patients have VF defects with retained acuity .
Different studies , refer to multiple prognostic factors in patients with compressive parachiasmal tumors. Age and optic disc pallor were found to be predictive of the visual outcome by former but not by later. The duration of symptoms before surgery can lead to a poor visual outcome. However, this seemed to correlate more with the depth of the preoperative visual deficit in a study by Cohen et al. , and was not statistically significant on multivariate analysis in another study by Sullivan et al.  When a Goldmann perimeter was used, the preoperative VF defect had prognostic value in two studies , and did not in two other studies ,. In a study by Gnanalingham et al. , Humphrey VF showed that temporal-superior and temporal-inferior VF defects were predictive of the final VF defect, but only the temporal-superior quadrant maintained that prognostic value in a multivariate analysis including age and duration of visual symptoms.
The lack of a clear result from these studies makes it difficult to predict the visual outcome in a single patient. Jacob et al.  compared the anatomical results of retinal nerve fiber layer around the disc using optical coherence tomography with SAP. They classified the patients into groups and found that the more the depth of field defects preoperatively, the more the worsening of postfield changes. Complete resolution occurred in 43% of their cases. No special measurements of temporal sensitivity were taken. In this study, the 15 patients were classified into three groups according to postoperative VF recovery: incomplete recovery in group 1; worsening in group 2; or complete resolution in group 3. Special attention was focused on temporal field sensitivity (measured by Lambert scale) as this hemifield carries the most deficits in the field of any chiasmal compressive lesion. It was found that group 3 had, preoperatively, the least MD, and the highest temporal sensitivity (best prognosis), compared with the other two groups. The lower the MD, as described in a study by Jacob et al. , the better the postoperative field results, as in group 3. We concluded that the more the temporal sensitivity, the better the prognosis of the field postoperatively. This finding was proved by Moon et al.  as well, but no classification was performed on their 18 cases as in the current study.
However, in this study, significant improvement, although incomplete, was seen in group 1 with preoperative temporal sensitivity as the prognostic value. Group 2 showed worsening of the field postoperatively, although there was lower MD and higher temporal sensitivity compared with group 1, agreeing with the results of Jacob et al. . This may be attributed to age (older patients) or short-term follow-up (3 months), which, in some patients, is considered insufficient for axonal function restoration. A more severely affected optic nerve and visual function may result in more prolonged degeneration and delayed restoration of retinal function.
| Conclusion|| |
In this series, the temporal field sensitivity was the best prognostic value in determining the VF outcome in decompression surgery for sellar and parasellar tumors. The lower the preoperative temporal sensitivity, the more significant the field improvement. Further studies are needed to confirm this result.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]