Herniation of the suprasellar visual system and third ventricle into empty sellae: morphologic and clinical considerations

Chiasmapexy for secondary empty sella syndrome: diagnostic and therapeutic considerations

PURPOSE

Secondary empty sella syndrome (SESS) following pituitary surgery remains a diagnostic and therapeutic challenge. The aim of this study was to specify the diagnostic criteria, surgical indications and results of chiasmapexy in the SESS.

METHODS

Three cases from two experienced neurosurgical centers were collected and the available literature was reviewed.

RESULTS

The 3 patients were operated for a giant non-functioning pituitary adenoma, a cystic macroprolactinoma, and an arachnoid cyst respectively. Postoperative visual outcome was initially improved, and then worsened progressively. At the time of SESS diagnosis, visual field defect was severe in all cases with optic nerve (ON) atrophy in 2 cases. Patients were operated via an endoscopic endonasal extradural approach. One patient was re-operated because of early fat reabsorption. Visual outcome improved in 1 case and stabilized in 2 cases. Statistical analyses performed on 24 cases from the literature review highlighted that patient age and severity of the preoperative visual defect were respectively significant and nearly significant prognostic factors for visual outcome, unlike the surgical technique.

CONCLUSION

T2-weighted or CISS/FIESTA sequence MRI is mandatory to visualize adhesions, ON kinking and neurovascular conflict. TS approach is the most commonly used approach. The literature review could not conclude on the need for an intra or extradural approach suggesting case by case adapted strategy. Intrasellar packing with non-absorbable material such as bone should be considered. Severity of the visual loss clearly decreases the visual outcome suggesting early chiasmapexy. In case of severe and long standing symptoms before surgery, benefits and surgical risks should be carefully balanced.

Chiasmal herniation following treatment of pituitary macroadenoma

PURPOSE

To evaluate whether the occurrence of chiasmal herniation coincides with visual field (VF) deterioration and to compare the course of VF defects in patients with and without radiological chiasmal herniation following treatment of pituitary adenoma.

METHODS

This retrospective cohort study included 48 pituitary macroadenoma patients with chiasm compression, divided into three groups: Group 1 (N = 12), downward displaced optic chiasm and deteriorated VFs; Group 2 (N = 16), downward displaced optic chiasm; Group 3 (N = 20), control-group matched for tumour size and follow-up VFs, in mean deviation (dB). VFs were compared over time and a severity index, Chiasm Herniation Scale (CHS), for herniation based on radiological parameters was designed.

RESULTS

After treatment, all groups showed improvement of VFs (Gr1: 2.97 dB p = 0.097, Gr2: 4.52 dB p = 0.001 and Gr3: 5.16 dB p = 0.000), followed by long-term gradual deterioration. The course of VFs between patients with and without herniation was not significantly different (p = 0.143), neither was there a difference in the course before and after herniation (p = 0.297). The median time till onset of herniation was 40 months (IQR 6 month-10 years) and did not significantly differ (p = 0.172) between the groups. There was no relation between VFs and the degree of herniation (p = 0.729).

CONCLUSION

Herniation does not appear to have clinical relevance with respect to VF outcome. The newly designed CHS is the first scoring system to quantify the severity of herniation and, in the absence of alternatives, may be useful to describe MRI findings to serve future added value in larger sized outcome studies.

Spontaneous improvement of secondary empty sella syndrome due to re-expansion of an intrasellar cyst: A case report

Background:

In patients with secondary empty sella syndrome (ESS), optic nerve herniation into the sella turcica is caused by shrinkage of the mass lesion at the sella turcica, resulting in visual disturbance. ESS is often surgically treated using chiasmapexy. Here, we report the first case of spontaneous improvement in a patient with ESS.

Case Description:

A 69-year-old woman presented with a month-long history of visual disturbance in the right eye, poor visual acuity, and quadrantanopia in her upper temporal visual field. Magnetic resonance (MR) imaging showed herniation of her right optic nerve and gyrus rectus into the sella turcica. The visual disturbance gradually improved, and the patient’s vision became almost normal after a month without any treatment. On repeated MR imaging, it was observed that the herniation of the right optic nerve and gyrus rectus disappeared due to an intrasellar cyst re-expansion. The secondary ESS caused by the shrinkage of the intrasellar cyst resulted in the visual disturbance and re-expansion of the cyst resulted in spontaneous improvement of symptoms. The visual disturbance did not recur for a year.

Conclusion:

Patients with secondary ESS without severe symptoms may be followed up conservatively. However, surgical treatment should be applied if symptoms deteriorate or do not improve.

Retinal nerve fibre and ganglion cell inner plexiform layer analysis by optical coherence tomography in asymptomatic empty sella patients

Purpose: To investigate the clinical importance of the thicknesses of the retinal nerve fibre (RNFL) and ganglion cell and inner plexiform layer (GCL+) by spectral domain optic coherence tomography (SD-OCT) in asymptomatic empty sella (ES) patients.Materials and methods: In this cross-sectional, non-randomized prospective study, 44 ES patients and 74 age- and sex-matched healthy individuals were evaluated. All the patients and controls competed an automated 30-2 visual field (VF) test. The mean deviation (MD), pattern standard deviation (PSD), RNFL, and GCL + thickness values obtained with SD-OCT were compared statistically between the two groups.Results: No marked VF defects were found in either group, and there was no statistically significant between-group difference in MD or PSD values. In terms of RNFL thickness, the average and superior quadrant RNFL values of the ES patients were thinner than those of the controls, with statistical significance (p = 0.013 and p = 0.043, respectively). Although other measured RNFL quadrant thicknesses and foveal thickness (FT), macular volume (MV), and average macular thickness (AMT) values were reduced in the ES group, these differences were not statistically significant. The average GCL + value and GCL + values in six sectors in the patient group were significantly lower than those in the control group.Conclusions: Asymptomatic ES patients have a risk of primary ES syndrome and should be followed up using a multidisciplinary approach. Objective and quantitative RNFL and GCL + thickness measurements obtained with OCT can provide valuable data for monitoring these patients.

Treatment of empty sella associated with visual impairment: a systematic review of chiasmapexy techniques

PURPOSE

Chiasmapexy is a poorly described surgical procedure adopted to correct the downward displacement of suprasellar visual system (SVS) into an empty sella (ES) causing visual worsening. The aim of our study is to define the indications for extradural and intradural chiasmapexy.

METHODS

A systematic literature review has been performed on MEDLINE database (US National Library of Medicine), including only articles that depicted cases of surgically treated patients affected by ES and progressive delayed visual worsening. Moreover, we have reported three cases of secondary ES syndrome (SESS) with visual worsening treated in our Department with transsphenoidal (TS) microsurgical intradural approach. Finally, we have compared the results of extradural and intradural chiasmapexy described in literature.

RESULTS

The etiology of visual impairment is different in primary and secondary ESS. In primary ESS (PESS) the only predisposing factor is a dehiscence of diaphragma sellae, and the anatomical distortion caused by displacement of optic chiasm or traction of pituitary stalk and infundibulum may determine a direct injury of neural fibers and ischemic damage of SVS. In PESS the mechanical elevation of SVS performed through extradural approach is sufficient to resolve the main pathologic mechanism. In SESS, arachnoidal adhesions play an important role in addition to downward herniation of SVS. Consequently, the surgical technique should provide elevation of SVS combined to intradural release of scar tissue and arachnoidal adhesions. In treatment of SESS, the intradural approaches result to be more effective, guaranteeing the best visual outcomes with the lowest complications rates.

CONCLUSIONS

The intradural chiasmapexy is indicated in treatment of SESS, instead the extradural approaches are suggested for surgical management of PESS.

Visual Deterioration and Herniation of the Anterior Cerebral Artery: Unusual Presentation of an Empty Sella Syndrome Complicating Decompression of a Rathke Cleft Cyst

Clinical manifestations of empty sella syndrome include hypopituitarism cerebrospinal fluid rhinorrhea, headache, and visual abnormalities. A 21-year-old woman reported a 6-month history of worsening vision 3 years after decompression of a sellar-suprasellar Rathke cleft cyst. Her magnetic resonance imaging (MRI) showed a well-defined recurrent cyst in the sellar-suprasellar region causing chiasmatic compression. She underwent an endonasal, endoscopic decompression of the cyst, with subsequent improvement in her vision. A postoperative computed tomography confirmed good decompression of the cyst. Ten days after surgery, she reported sudden loss of vision in both eyes. MRI revealed an empty sella with herniation of both anterior cerebral arteries and optic chiasm into the sella. She underwent transnasal packing of the sellar floor with fat graft and bone plaques, and experienced gradual improvement in vision in her right eye.

Brain and Optic Chiasm Herniation into Sella after Pituitary Tumor Apoplexy

Brain and optic chiasm herniation has been rarely reported following dopamine agonist treatment for large prolactinomas. We report a case of brain and optical chiasm herniation, secondary to an empty sella due to apoplexy of a prolactinoma, and we focus on the specific presentation of this case. A 32-year-old female presented to a neurologist complaining of headaches. Her past medical history was significant for acute vision loss in both eyes accompanied by right third nerve palsy when she was 16 years old. She does not recall any endocrine or imaging evaluation at that time and she had spontaneous partial recovery of left eye vision within 3 months, with permanent blindness of right eye. She did not return to any follow-up until her neurologist consultation. Brain magnetic resonance imaging (MRI) revealed herniation of frontal lobe and optic chiasm into the pituitary sella, as well as a pituitary hypointense lesion measuring 5 mm × 5 mm after gadolinium injection. Prolactin levels were 206 ng/ml (4.79-23.3 ng/ml). Repeated prolactin was 258 ng/ml (4.79-23.3 ng/ml). She was started on bromocriptine 2.5 mg/day. Prolactin levels and menstrual cycles normalized. A repeat brain MRI performed 5 months later showed disappearance of pituitary mass, with no changes in brain and chiasmal herniation. To our knowledge, this is the first reported case of brain associated with chiasm herniation secondary to pituitary apoplexy of a prolactinoma. In conclusion, this case highlights that frontal lobe herniation in combination with optic chiasm herniation can be a complication of pituitary tumor apoplexy. Long-term surveillance of patients with pituitary apoplexy is warranted to detect delayed complications.

Comparison of MR Imaging and CT in Pituitary Macroadenomas

The findings on mid-field MR imaging and CT were compared retrospectively in 65 patients with pituitary macroadenomas. The evaluation comprised tumour extension and delineation, invasiveness, relationship to adjacent structures, and internal tumoral changes. MR was superior to CT except in the demonstration of bone changes and tumour calcification. The superiority of MR was most pronounced regarding cavernous sinus invasion, tumour relationship to the carotid arteries and optic chiasm, and tumour haemorrhage. Extensive bone changes were visualized with both methods; erosions were often seen only with CT. It is concluded that MR is the preferable method for evaluation of pituitary macroadenomas. CT is useful as a supplementary modality when detailed information on bone anatomy is required, particularly if a transsphenoidal surgical approach is contemplated.

Sellar reconstruction without intrasellar packing after endoscopic surgery of pituitary macroadenomas is better than its reputation

Objectives: Sellar reconstruction with intrasellar packing following endoscopic resection of pituitary macroadenomas remains a subject of clinical and radiological discussion particularly, when an intraoperative cerebrospinal fluid (CSF) leakage is absent. This study was conducted to contribute our experience with sellar reconstruction after a standard endoscopic surgery of pituitary macroadenomas without intraoperative CSF leakage to the ongoing discussion between techniques with and without intrasellar packing.

Methods: A consecutive series of 47 pituitary macroadenomas undergoing excision via a standard endoscopic endonasal transsphenoidal surgery (EETS) without evident intraoperative CSF leakage were retrospectively evaluated over a 10-months mean follow-up period. According to the sellar reconstruction technique, three groups could be identified: Group A – with no intrasellar packing, Group B – with haemostatic materials packing, and Group C – with abdominal fat packing. Postoperative clinical and radiological assessments of the three groups were documented and analyzed for differences in outcome.

Results: Postoperative clinical assessment did not differ significantly between the three groups. In group A, postoperative CSF leakage, sphenoid sinusitis and empty sella syndrome were not observed. However, a significant difference in radiological assessment could be identified; the interpretation of sellar contents in postoperative MRI of group A succeeded earlier and more reliably than in other groups with intrasellar packing.

Conclusions: There is no difference in the incidence of postoperative CSF leakage and empty sella syndrome among the various reconstructive techniques with and without intrasellar packing, irrespective of size and extension of the pituitary adenoma. Sellar reconstruction without intrasellar packing following a standard EETS is not inferior to other techniques with packing and even shows more radiological advantages, which made it our preferred technique, at least if no intraoperative CSF leakage is evident.

Endonasal endoscopic transsphenoidal chiasmapexy using a clival cranial base cranioplasty for visual loss from massive empty sella following macroprolactinoma treatment with bromocriptine: case report

Visual deterioration after dopamine-agonist treatment of prolactinomas associated with empty sella syndrome and secondary optic apparatus traction is a rare event. Chiasmapexy has been described as a viable treatment option, although few cases exist in the literature. Here, a novel endonasal endoscopic approach to chiasmapexy is described and its efficacy is demonstrated in a case report. A 55-year-old female patient with a history of a giant prolactinoma and 14 years of treatment using dopaminergic agonist therapy presented to our institution with a 1-month history of visual changes. Neuroophthalmological examination confirmed severe bitemporal field defects, and MRI revealed a large empty sella with downward optic chiasmal herniation. Endoscopic endonasal chiasmapexy was performed by elevating the chiasm with lumbar drainage and filling the clival and sellar defect with an extradural liquid (HydroSet; a cranioplasty bone cement), and a piece of AlloDerm was used to cover and cushion the chiasm. Postoperative imaging demonstrated successful anatomical elevation of the optic apparatus, and the patient showed functional improvement in the visual field at 3 months postoperatively. Although rare, massive empty sellar and chiasmal descent from macroadenoma treatment can result in progressive visual loss. Here, a novel technique of endonasal endoscopic extradural cranioplasty aided by lumbar drainage is reported, which appears to be an effective technique for stabilizing and possibly reversing anatomical and visual deterioration.

Intraoperative fat placement in surgically refractory parasellar neoplasms to facilitate stereotactic radiosurgery

BACKGROUND

In this article, we report on the technique of placing fat in between a sellar or parasellar neoplasm and the optic chiasm to possibly protect the optic chiasm from sequelae of radiation.

METHODS

A review was performed on three patients, each of whom had planned subtotal resection with fat placed near their optic chiasm to facilitate future radiosurgery.

RESULTS

Follow-up on our three patients varied from 6 months to 3 years post-stereotactic radiosurgery. The fat remained stable and in place. The tumors either remained stable or reduced in size. No infections, postoperative marker dependent neurological complications or unusual symptoms were encountered.

CONCLUSIONS

Placement of fat between a parasellar neoplasm and the optic chiasm appears to be a safe approach to help define the tumor chiasm space, helping to facilitate radiosurgery. Future experience is warranted to determine the efficacy of this technique.

Brain and optic chiasmal herniation following cabergoline treatment for a giant prolactinoma: wait or intervene?

OBJECTIVE

Dopamine agonists (DA) are the treatment of choice in patients with macroprolactinomas. Brain and optic chiasm herniation are unusual complications following treatment with DA.

REPORT

We present a case of a giant prolactinoma complicated by visual deterioration following cabergoline treatment. A 42-year-old man was admitted with seizures, right visual loss and visual defect in the upper left temporal quadrant. Magnetic resonance imaging (MRI) identified a giant adenoma, which proved to be a prolactinoma, compressing the optic chiasm and extending into the suprasellar region. Treatment with cabergoline was initiated resulting in improvement in visual fields, tumor shrinkage and prolactin level decrease. Five months later and despite tumor reduction, a deterioration of his visual fields was observed. The second MRI revealed brain and optic chiasmal herniation into the pituitary sella. Cabergoline dose was reduced and surgical resection of the adenoma along with untethering of the optic nerve was performed leading to improvement of the visual defects.

CONCLUSIONS

This report describes a rare case of brain and optic chiasmal herniation attributed to DA therapy for a macroprolactinoma. It is important for clinicians to examine visual fields and promptly identify any visual deterioration in patients with macroprolactinomas receiving DA treatment.

Primary empty sella (PES): a review of 175 cases

The term primary empty sella (PES) makes reference to the herniation of the subarachnoid space within the sella turcica in patients with no history of pituitary tumor, surgery or radiotherapy. To retrospectively assess clinical features, radiological findings and the biochemical endocrine function from the records of 175 patients with a diagnosis of PES. One hundred seventy-five patients (150 females) were studied. The mean age at diagnosis was 48.2 ± 14 year. Most diagnoses were made by magnetic resonance imaging (n = 172). In most patients, the pituitary function was assessed by basal pituitary hormones measurements. Pituitary scans were ordered for different reasons: headache (33.1 %), endocrine disorders (30.6 %), neurological symptoms (12.5 %), visual disturbances (8.75 %), abnormalities on sella turcica radiograph (8.75 %) and others (6.25 %). Multiple pregnancies were observed in 58.3 % of women; headaches, obesity, and hypertension were found in 59.4, 49.5, and 27.3 % of the studied population, respectively. Mild hyperprolactinemia (<50 ng/ml) was present in 11.6 % of women and 17.3 % of men. Twenty-eight percent of our patients had some degree of hypopituitarism. In the male population, hypopituitarism represented 64 % of cases, whereas it accounted for 22 % of all females. PES seems to be more commonly found in middle-aged women, with a history of multiple pregnancies. In most patients, PES was discovered as an incidental finding on imaging studies, while in almost a quarter of patients PES was found during the diagnostic evaluation of anterior pituitary deficiency, which was more common in men.

Brain and optic chiasmal herniations into sella after cabergoline therapy of giant prolactinoma

Optic chiasmal herniation following dopamine agonist therapy is a rare complication in patients with giant prolactinomas. But there are a few case reports of brain and chiasmal herniation following medical therapy in such cases. We report a young man who developed secondary visual loss and seizures after 6 months of medical treatment with cabergoline for giant prolactinoma. Magnetic resonance imaging of hypothalamic pituitary region revealed optic chiasmal and frontal lobe herniation into sella. There was marginal improvement in his vision after cabergoline dose reduction. The present case report highlights frontal lobe herniation in conjunction with optic chiasmal herniation as a very rare complication of medical therapy of giant prolactinoma. Different treatment options of this condition are being discussed.

Persisting embryonal infundibular recess

Persisting embryonal infundibular recess (PEIR) is a rare anomaly of the third ventricular floor that has an unclear pathogenesis. In all 7 previously described cases, PEIR was present in adult patients and was invariably associated with hydrocephalus and, in 4 reported cases, with an empty sella. These associated findings led to speculations about the role of increased intraventricular pressure in the development of PEIR.

In the present case, PEIR was found in a 24-year-old man without the presence of hydrocephalus or empty sella. Disorders of pituitary function had been present since childhood. Magnetic resonance imaging revealed a cystic expansion in an enlarged sella turcica. A communication between the third ventricle and the sellar cyst was suspected but not apparent. During transcranial surgery, the connection was confirmed. Later, higher-quality MR imaging investigations clearly showed a communication between the third ventricle and the sellar cyst through a channel in the tubular pituitary stalk. This observation and knowledge about the embryology of this region suggests that PEIR may be a developmental anomaly caused by failure of obliteration of the distal part of primary embryonal diencephalic evagination. Thus, PEIR is an extension of the third ventricular cavity into the sella.

Although PEIR is a rare anomaly, it is important to identify when planning a procedure on cystic lesions of the sella. Because attempts at removal using the transsphenoidal approach would lead to a communication between the third ventricle and the nasal cavity, a watertight reconstruction of the sellar floor is necessary.

Brain & chiasmal herniations into sella after medical treatment of prolactinoma

BACKGROUND

Dopamine agonists are widely used in the treatment of pituitary prolactinomas. We report a case of inferior mesial frontal lobe (gyrus rectus) and chiasmal herniations into an enlarged sella following successful medical treatment of a pituitary macroadenoma.

METHOD

A 71-year-old healthy man presented to medical attention with visual complaints. On examination, he was found to have bitemporal hemianopsia. Endocrine evaluation revealed an elevated prolactin level. He was treated medically with a dopamine agonist (bromocriptine).

RESULTS

Evaluation after one year of medical treatment revealed stabilization of the patient's vision, with a significant bitemporal field loss. Serum prolactin levels normalized (5.16 ng/ml). The MRI of the sella showed almost complete disappearance of the tumor, resulting in right mesial frontal lobe herniation inferiorly into an enlarged sella with associated chiasmal deformation.

CONCLUSIONS

We report a case where successful medical treatment of a large pituitary prolactinoma has resulted in inferior frontal lobe and chiasmal herniatons into an enlarged sella.

Her vision was tied down

A 50-year-old female presented with progressive painless vision loss in the left eye and was subsequently diagnosed to have a pituitary macroadenoma, consistent with a prolactinoma, which was compressing the chiasm primarily on the left and involving the left cavernous sinus. She was treated with oral bromocriptine, resulting in marked shrinkage of the tumor and significant visual field recovery. Subsequently, she again began noting progressive vision loss in both eyes and was initially thought to have pituitary tumor regrowth. Repeat brain MRI, however, showed chiasmal prolapse with inferior tethering into an empty sella. Surgical fat padding to reposition the chiasm resulted in visual improvement with a different visual field pattern in the left eye. The clinical manifestations and etiopathogenesis of the empty sella syndrome are discussed.

Transsphenoidal treatment of empty sella by means of a silastic coil: technical note

OBJECTIVE AND IMPORTANCE

Several methods have been proposed to achieve transsphenoidal arachnoid mobilization and chiasmapexy in symptomatic empty sella (primary or secondary empty sella syndrome). These procedures are often difficult to perform and have not always had satisfactory long-term outcomes because of the difficulty of achieving adequate and long-lasting sellar filling over time. The volume of fat or muscle packing decreases over time as a result of scar retraction. The same problem may occur with intrasellar balloon placement because of deflation of the balloon.

TECHNIQUE

We propose extradural packing accomplished through a transsphenoidal approach, using a Silastic (Dow Corning, Auburn, MI) coil, fashioned by means of a ventricular catheter arranged as a spiral.

RESULTS

This technique was used in four patients with satisfactory and long-lasting clinical results. It presents several advantages over previous methods: it can be tailored to each patient; Silastic is an inert substance, and therefore scarring, with consequent shrinkage, does not occur; and because the coil is very elastic, it presents few risks of inflammatory complications or of excessive compression of sellar, parasellar, and suprasellar structures. Furthermore, this technique does not require a supplementary skin incision to harvest autologous tissues (fat, muscle, or fascia lata). A skilled neurosurgeon can perform the procedure in a few minutes with more ease and less expense than other techniques.

CONCLUSION

The reported technique is a valid alternative to classic transsphenoidal extradural packing.

Primary empty sella syndrome: the role of visual system herniation

BACKGROUND

It has been traditionally accepted that ophthalmologic alterations in cases of primary empty sella syndrome are caused by the herniation of the visual system in the pituitary fossa, but this cannot be stated categorically.

METHODS

Two female patients with primary empty sella syndrome and visual field defects were included in this series. The peculiarity of these cases was that in neither of them was there an evident herniation of the visual system. In the absence of other causes that could explain the visual defects, the patients were operated on through a transsphenoidal approach.

RESULTS

Both patients showed immediate improvement of their visual deficits without recurrence. Postoperative imaging studies have shown continuance of an adequate elevation of the sellar contents during the 5-year follow-up period.

CONCLUSIONS

Visual field defects in cases of primary empty sella syndrome may occur even without radiological evidence of herniation of the visual system. The fact that the two patients described in this paper improved after surgery supports other reports that in this syndrome traction on the infundibular stalk may cause some microscopic anatomic alteration in the visual system or in its vascular supply that is not evident on imaging studies.

Delayed visual loss following pergolide treatment of a prolactinoma

A patient who had achieved marked improvement in vision and shrinkage of a prolactinoma following treatment with pergolide (0.1 mg/day) suffered a marked worsening of vision 7 months after continued treatment at the same dose. Brain magnetic resonance imaging (MRI) at the time of visual loss showed further shrinkage of the tumor and prolapse of the chiasm into the pituitary fossa. The dose of pergolide was cut in half (0.05 mg/day); 12 months later, vision had completely recovered. Brain MRI at the time of visual recovery showed no change in the position of the prolapsed chiasm. This is the 11th reported case of delayed visual loss following dopaminergic treatment of prolactinoma. Recovery of vision always occurs with reduction of the medication dosage. Many patients whose prolactinomas are treated in this fashion display chiasmal prolapse, and few suffer visual loss. Considering that visual recovery occurs without a visible change in the position of the chiasm, traction is an unlikely cause of delayed visual loss. Therefore, the term chiasmal traction syndrome, used to describe visual loss with prolapsed chiasm following surgical and radiation treatment of sellar tumors, should not be applied in this setting lest it prompt consideration of surgical chiasmapexy. The proper management is reduction of the dopaminergic agonist dosage.

Optic chiasmal herniation--an under recognized complication of dopamine agonist therapy for macroprolactinoma

The initial presentation of macroprolactinoma with visual field impairment, especially in males, is well recognized. Successful treatment with dopamine agonist therapy is characterized by a reduction in hyperprolactinaemia and often rapid and progressive resolution of the visual impairment. A small proportion of patients may subsequently develop a secondary deterioration in both their visual fields and visual acuities despite normalization of prolactin levels and tumour shrinkage. When pituitary apoplexy can be excluded this may result from traction on the optic chiasm which is pulled down into the now partially empty sella. We report a series of seven patients in whom chiasmal traction is believed to be the cause of their secondary deterioration in visual acuity occurring after dopamine agonist therapy for macroprolactinoma. The clinical history of two patients both of whom had rapid resolution of field defect with bromocriptine therapy but subsequently developed a recurrence of their bitemporal hemianopia is detailed. In both patients MRI scanning showed not only tumour involution but also marked optic chiasm herniation into the pituitary fossa. Surgical treatment was considered too risky; but on reduction of bromocriptine dosage the field defect improved in both cases; there was a modest elevation of prolactin and a degree of tumour re-expansion. The latter is believed to have released tethering of the optic chiasm and/or its vascular supply and thus obviated the need for surgery. Regular monitoring of visual fields in patients with macroprolactinoma receiving medical treatment is therefore important. Early recognition of secondary field loss due to chiasmal herniation enables correction of the visual field loss by manipulation of the medical therapy.

Empty sella syndrome: does it exist in children?

OBJECT

The empty sella syndrome (ESS) is well documented in adults, and although the same phenomenon of herniation of the arachnoid space into the enlarged sella turcica has been noted in children, it is not widely known that children suffer from this syndrome. Therefore, the aims of this paper are to increase neurosurgeons' awareness of the existence of this phenomenon in children and to add to the scant body of literature on the subject.

METHODS

The authors treated 12 children, ranging in age between 2 and 8 years, in whom neuroradiological studies demonstrated an enlarged sella turcica filled with cerebrospinal fluid and herniation of suprasellar and arachnoid spaces. The causes of ESS in these children were high intracranial pressure, neglected or improperly treated hydrocephalus, and suprasellar arachnoid cyst. Primary ESS was found as well. Most of the children presented with headache, abnormal body weight (the majority being underweight), and short stature. The results of hormone assays were normal in all children.

CONCLUSIONS

If undiagnosed and untreated, ESS in children may lead to serious consequences, including impairment of pituitary and hypothalamic function and damage to the optic chiasm. It is important to raise awareness in the neurosurgical community about the existence of ESS in children so that it can be diagnosed and treated at an early stage. A classification system for the diaphragma sellae is recapitulated.

Empty sella syndrome: does it exist in children?

The empty sella syndrome (ESS) is well documented in adults and although the same phenomenon of herniation of the arachnoid space into the enlarged sella turcica has been noted in children, it is not widely known that children suffer from this syndrome. Therefore, the aims of this paper are to increase neurosurgeons' awareness of the existence of this phenomenon in children and to add to the scant body of literature on the subject.

The authors treated 12 children, ranging in age between 2 and 8 years in whom neuroradiological studies demonstrated an enlarged sella turcica filled with cerebrospinal fluid and herniation of suprasellar and arachnoid spaces. The causes of ESS in these children were high intracranial pressure, neglected or improperly treated hydrocephalus, and suprasellar arachnoid cyst. Primary ESS was found as well. Most of the children presented with headache, abnormal body weight (the majority being underweight), and short stature. The results of hormone assays were normal in all children.

If undiagnosed and untreated, ESS in children may lead to serious consequences, including impairment of pituitary and hypothalamic function and damage to the optic chiasm. It is important to raise awareness in the neurosurgical community about the existence of ESS in children so that it can be diagnosed and treated at an early stage. A classification system for the diaphragma sellae is recapitulated.

Long-term visual changes following pituitary irradiation

PURPOSE

To analyze possible long-term effects of pituitary irradiation on visual fields and acuity.

METHODS AND MATERIALS

Eighty-six patients were treated with radiotherapy for pituitary tumors at the National Cancer Institute between 1980 and 1991. Twenty-one patients had baseline preradiation and long-term follow-up visual fields. Eyes were followed with serial Goldmann or Humphrey visual field testing. Neuroradiologic correlation was made with the available brain scans. There were 12 females and 9 males with an median age of 44. Eighteen patients had hormone-secreting tumors and three had chromophobe adenomas. All but one patient with an inoperable invasive macroadenoma were irradiated after one or more transphenoidal resections or a craniotomy. The indications for radiation in the operable patients were: nine patients, partial tumor resection; nine patients, tumor recurrence; and two patients, persistent hormonal elevation after surgery. The median dose delivered was 50 Gy (45-59.4 Gy). The average field size was 6 x 6 cm (5 x 5 cm to 10 x 12.5 cm).

RESULTS

With a median follow-up of 48 months (14-128) after radiotherapy, 1 out of 21 patients has recurred (at 8 months) and all patients are alive. Of the 38 sighted eyes, 27 had normal visual fields before and after radiation, 7 eyes showed improvement, and 4 eyes had a stable defect, mostly in the superior temporal region. There were no cases of radiation-induced visual field or acuity deterioration. Six out of 21 patients (29%) had neurologic symptoms in follow-up, most of which appeared vascular in nature. Four patients complained of atypical migranous-like headaches that first began 1.5-3 years following treatment. One patient complained of recurrent vertical diplopia and one patient had a cerebral vascular accident 7 years following therapy. A dose-related association with these neurovascular symptoms approached statistical significance. Only 1 out of 11 (9%) patients who received doses less than or equal to 50 Gy developed these symptoms, whereas 5 out of 10 (50%) patients who received doses greater than 50 Gy developed symptoms (p2 = 0.064).

CONCLUSION

Postoperative radiation for partially resected or recurrent pituitary adenomas using megavoltage radiation, as well as modern field arrangements and fractionation, is extremely effective and safe. Ninety-five percent of patients are free of recurrence with not deterioration in the visual fields or acuities. Some patients experienced neurovascular symptoms (mostly vascular headaches) following surgery and radiation. There is a trend (p2 = 0.064) toward increased symptoms following higher radiation doses.

Magnetic resonance imaging of the optic chiasm

Magnetic resonance imaging (MRI) has become an important diagnostic modality for the evaluation of patients with chiasmal or perichiasmal disease. In this review, normal chiasmal anatomy and various pathologic conditions will be illustrated to demonstrate the advantages of MRI over computed tomography (CT). MRI is the neuroimaging method of choice in chiasmal evaluation, but sometimes it may be complemented by CT scanning.