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Neurology India, Vol. 59, No. 2, March-April, 2011, pp. 289-292 Case Report Transsellar transsphenoidal encephalocele: A series of four cases Yashpal S Rathore, Sumit Sinha, AK Mahapatra Department of Neurosurgery, C. N. Center, All India Institute of Medical Sciences, New Delhi, India Correspondence Address: A K Mahapatra, Department of Neurosurgery, C. N. Center, All India Institute of Medical Sciences, New Delhi - 110 029, India, akmahapatra_22000@yahoo.com Date of Submission: 06-Dec-2010 Code Number: ni11077 PMID: 21483136 DOI: 10.4103/0028-3886.79157 Abstract Transsellar transsphenoidal encephalocele is the least common type of basal encephalocele. We present a series of four cases of transsellar transsphenoidal encephalocele. Clinical findings, imaging reviews, surgical repair techniques and postoperative morbidity are discussed with the relevant literature. Non contrast CT scan head with 3D reconstruction and magnetic resonance imaging should be done in all patients of transsphenoidal encephalocele. Endocrine assessment is also essential. Repair of a transsphenoidal encephalocele should be coordinated between a team of neurosurgeons and ENT surgeon. Our surgical outcome supports the transpalatal/ transnasal approach over the transcranial approach.Keywords: Basal encephalocele, transsellar transsphenoidal encephalocele, transpalatal approach Introduction Encephalocele incidence occurs among one in every 3000 - 5000 live births. [1],[2],[3] Basal cephaloceles are less common with an estimated incidence of 1 in 35,000 live births. [4],[5],[6] Basal encephaloceles are classified into transethmoidal, spheno-orbital, sphenomaxillary and transsphenoidal. The trans-sphenoidal variant accounts for 5% of basal encephalocele (1 in 70,000 live births). [7] We report four patients with this rare condition and highlight the issues related to the management of this rare entity. Case Reports In the last 21 years (1989 to 2010) four patients (5 months - 14 years) with transsellar transsphenoidal encephalocele have been operated. The clinical features, associated anomalies, and imaging findings are given in [Table - 1]. Surgical repair of the transsellar transsphenoidal encephalocele was done by a team of neurosurgeons and an ENT surgeon [Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5] and [Figure - 6]. All patients received perioperative steroids. The encephalocele sac was opened in two patients and the contents were reduced with no attempt at resection of the redundant dura or neural structure. In the other two patients the sac was reduced using surface coagulation. The skull base was repaired using a nasopharyngeal mucosal flap (Case 1), the split rib graft was fixed with mini plates and screws, reinforced by a nasopharyngeal mucosal flap (Case 2), the septal cartilage with fascial graft and tissue glue (Case 3), and titanium mesh and fascial graft with tissue glue (Case 4). Case 1 developed cerebrospinal fluid (CSF) postoperative rhinorrhea and developed fatal Kleibsella pneumonae meningitis. Case 4 developed severe hyponatremia in the postoperative period and was managed with 3% hypertonic saline Discussion Transsphenoidal encephalocele is thought to be due to the persistence of a craniopharyngeal or a transsphenoidal canal. It is a vertical midline skull base defect, with a diameter usually < 1.5 mm, and extends from the sellar floor to the nasopharynx. Normally, the craniopharyngeal canal disappears. In a majority of the patients the diagnosis is established in the first year of life. However, without characteristic facies, the diagnosis can be delayed to adolescence or adulthood. The clinical features include respiratory difficulties, feeding difficulties, episodes of recurrent meningitis, and endocrine abnormalities. Respiratory and feeding difficulties are related to a mass in the oral or nasal cavity. Associated congenital anomalies are seen in about a third of the patients and include hypertelorism, median nasal fissure, broad nasal root, and cleft lip or palate. The optic malformations include anophthalmia or microphthalmia, colobomas, retinal abnormalities, morning glory syndrome, and optic nerve or chiasm hypoplasia. The cerebral malformations include agenesis of the corpus callosum in up to 50% of the cases, hydrocephalus, and pituitary dystopia or hypoplasia. [8],[9],[10] Advanced imaging studies are necessary to confirm the diagnosis as well as to define any neural or vascular elements in the sac. A non-contrast computed tomography (CT) head scan with 3D reconstruction is invaluable in reconstruction of the skull base defect. Magnetic resonance imaging (MRI) of the brain is helpful to define the contents of the sac. Endocrine assessment should be done in every patient. Hypothalamic-pituitary dysfunction is often found in transsphenoidal encephaloceles and deficiency of Antidiuretic hormone and growth hormone are the most common finding. [11],[12] Both transcranial and transbasal approaches have been used to repair these lesions. However, the transcranial repair of these lesions is frequently unsuccessful and carries a mortality of over 50%. [13],[14] The fragility of the prolapsed cerebral tissue makes it difficult to preserve the cerebral tissue intact and to reposition it into the cranium. Access to the bone defect, particularly its posterior portion, is difficult, because of the distorted cerebral anatomy and abnormal vasculature. Most of the patients have associated cleft lip/palate, which can be operated at the same sitting using the transpalatal approach. There are relatively less chances of damaging the functional tissue in the wall of the encephalocele by using the transpalatal approach. The sac can be easily dissected off the palatal/nasal/nasopharyngeal/ spheniodal structure. Therefore, it is possible to preserve the sac and its contents and reposition it into the cranium, using the transpalatal approach. However, it is difficult to repair the skull base using this approach. Endoscopic repair has also been described in the literature. [6],[15] It allows resection of the encephalocele and subsequent reconstruction of the defect with a low rate of morbidity. References
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