Combined transnasal and transoral endoscopic approach to a transsphenoidal encephalocele in an infant

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1 DOI /s TECHNICAL NOTE Combined transnasal and transoral endoscopic approach to a transsphenoidal encephalocele in an infant Sien Hui Tan & Kein Seong Mun & Patricia Ann Chandran & Anura Michelle Manuel & Narayanan Prepageran & Vicknes Waran & Dharmendra Ganesan Received: 8 October 2014 /Accepted: 17 February 2015 # Springer-Verlag Berlin Heidelberg 2015 S. H. Tan (*): A. M. Manuel : N. Prepageran Department of Otolaryngology, Faculty of Medicine, University Malaya, Lembah Pantai, Kuala Lumpur, Malaysia sienic@yahoo.com K. S. Mun: P. A. Chandran Department of Pathology, Faculty of Medicine, University Malaya, Lembah Pantai, Kuala Lumpur, Malaysia V. Waran: D. Ganesan Department of Neurosurgery, Faculty of Medicine, University Malaya, Lembah Pantai, Kuala Lumpur, Malaysia Abstract Purpose This paper reports an unusual case of a transsphenoidal encephalocele and discusses our experience with a minimally invasive management. To the best of our knowledge, we present the first case of a combined endoscopic transnasal and transoral approach to a transsphenoidal encephalocele in an infant. Methods A17-day-oldboy,whowasreferredforfurtherassessment of upper airway obstruction, presented with respiratory distress and feeding difficulties. Bronchoscopy and imaging revealed a transsphenoidal encephalocele. At the age of 48 days, he underwent a combined endoscopic transnasal and transoral excision of the nasal component of the encephalocele. This approach, with the aid of neuronavigation, allows good demarcation of the extra-cranial neck of the transsphenoidal encephalocele. We were able to cauterize and carefully dissect the sac prior to excision. The defect of the neck was clearly visualized, and Valsalva manoeuvre was performed to exclude any CSF leak. As the defect was small, it was allowed to heal by secondary intention. Results The patient s recovery was uneventful, and he tolerated full feeds orally on day 2. Postoperative imaging demonstrated no evidence of recurrence of the nasal encephalocele. Endoscopic follow-up showed good healing of the mucosa and no cerebrospinal fluid leak. Conclusions The surgical management of transsphenoidal encephalocele in neonates and infants is challenging. We describe a safe technique with low morbidity in managing such a condition. The combined endoscopic transnasal and transoral approach with neuronavigation is a minimally invasive, safe and feasible alternative, even for children below 1 year of age. Keywords Transsphenoidal encephalocele. Endoscopy. Transnasal. Transoral. Paediatric Introduction Basal encephalocele is an uncommon congenital malformation in which the intracranial structures herniate through a defect in the skull base. The transsphenoidal encephalocele is the rarest subtype with an incidence of approximately 1 in 70,000 live births and represents 5 % of basal encephaloceles [1]. This paper aims to report an unusual case of a transsphenoidal encephalocele causing upper airway obstruction and to discuss our experience with a minimally invasive management. To the best of our knowledge, we present the first case of a combined endoscopic transnasal and transoral approach to a transsphenoidal encephalocele in an infant. Case report A 17-day-old boy was transferred to our tertiary referral centre for further assessment of upper airway obstruction. He was born at term via vacuum-assisted delivery following an uneventful pregnancy. There was no facial dysmorphism, cleft lip or cleft palate. Examination revealed a grade 2/6 pansystolic murmur at the left sternal edge, and echocardiogram reported a tiny patent foramen ovale, small secundum atrial septal defect, small ventricular septal defect and mild left pulmonary artery stenosis.

2 On day 4, he developed intermittent stridor with suprasternal and subcostal recessions. Worsening respiratory distress was noted on day 14, and oral intubation was performed. Although he was extubated 2 days later, he required continuous positive airway pressure ventilation. He was only able to maintain satisfactory saturation levels on room air with an oropharyngeal airway. A nasogastric tube was also inserted for nutrition, as he encountered feeding difficulties. Bronchoscopy demonstrated a large nasopharyngeal mass with a smooth surface obstructing 90 % of the airway. The remainder of the upper airway was unremarkable. Magnetic resonance imaging (MRI) revealed a midline soft tissue mass which did not enhance with contrast and consisted of mainly dysplastic brain tissue without significant vital structures. The mass extended from the suprasellar space through the body of the sphenoid bone into the nasopharyngeal, nasal and oropharyngeal cavities, thus confirming a transsphenoidal encephalocele (Fig. 1a). Computed tomography (CT) showed a potential defect at the sphenoid bone about 0.4 cm in diameter through which the encephalocele has herniated. However, it was also important to bear in mind that with this age group, the skull base is not completely ossified and the radiolucent cartilaginous bone that forms the skull base can appear as a defect on a CT scan (Fig. 1b). Preoperatively, his ophthalmological and endocrinological examinations were unremarkable. Nasopharyngeal culture demonstrated Pseudomonas aeruginosa,butthere was no clinical evidence of sepsis, meningitis or cerebrospinal fluid (CSF) leak. However, in view of his planned surgery, he was treated with antibiotics and his repeat culture showed normal flora. At the age of 48 days, he underwent a combined endoscopic transnasal and transoral excision of the nasal component of the encephalocele. Histopathological examination showed a well-circumscribed nodule composed of nests of glial tissue, separated by bands of fibrous tissue, covered by stratified squamous epithelium (Fig. 2a). The glial tissue was made up of astrocytes and oligodendrocytes (Fig. 2b), which were immunoreactive to glial fibrillary acid protein (GFAP). Scattered foreign body-type multinucleated giant cells (CD68 positive) and a few hemosiderin-laden macrophages were also present. Hence, based on the histological findings and the radiological appearance of herniation of intradural cranial content into the nasopharynx, the diagnosis of a nasal (transsphenoidal) encephalocele was concluded. The differential diagnosis of a hypothalamic hamartoma, which had herniated, was also taken into consideration but deemed less likely. Surgical technique The patient was positioned supine and registered to the Medtronic AxiEM electromagnetic navigation system using the MRI images. Rigid-rod endoscopes, with lenses of 2.7 and 4 mm in diameter, were mounted on a digital video camera system (Karl Storz). His nasal passages were prepared with Moffat s solution (1 ml of 1:1000 adrenaline, 2 ml of 10 % cocaine and 4 ml of 8.4 % sodium bicarbonate). First, we assessed the extent of the nasopharyngeal mass by advancing the 0 endoscope into the nasal cavity, followed by the 30 endoscope into the oral cavity. The mass was adherent anteriorly to the posterior septum and superoposteriorly to the roof of the nasopharynx (Fig. 3a and b). Next, we achieved good exposure of the oropharynx with a Boyle Davis mouth gag and a stitch placed in the uvula for upward retraction (Fig. 3c). The bilateral middle and inferior turbinates and soft palate were preserved. Using the transnasal approach initially, we resected the anterior attachment of the lesion with monopolar cauterization. We then employed a transoral approach to carefully cauterize the base portion of the mass with a bipolar instrument. Finally, the nasopharyngeal mass was removed in two parts, the inferior portion via the oral cavity and the superior remnant via the nasal cavity (Fig. 3d and e). Valsalva manoeuvre Fig. 1 a Preoperative sagittal MRI revealing a midline soft tissue mass consisting of mainly dysplastic brain tissue extending from the suprasellar space through the body of the sphenoid bone into the nasopharyngeal, nasal and oropharyngeal cavities. The oropharyngeal airway, used to maintain the patency of the airway, is compressing the sac against the nasopharyngeal wall b Preoperative coronal CT scan showing a potential defect at the sphenoid bone about 0.4 cm in diameter through which the encephalocele has herniated

3 Childs Nerv Syst Fig. 2 a The well-circumscribed nodule is covered by stratified squamous epithelium (H & E, original magnification 20) b The stroma is composed of benign fibrillary neural tissue which was positive for glial fibrillary acidic protein (H & E, original magnification 100) was then performed to ensure that there was no intraoperative CSF leak. As the defect was small, it was allowed to heal by secondary intention. Postoperative course The patient was extubated after surgery, and recovery was uneventful with no signs of respiratory distress, CSF leak or meningitis. He was tolerating full feeds orally on day 2 and discharged well on day 4. Serial postoperative MRI scans demonstrated no evidence of recurrence of the nasal encephalocele with the suprasellar, sellar and sphenoidal components unchanged (Fig. 4). Endoscopic follow-up showed good healing of the mucosa and no CSF leak. Discussion Basal encephaloceles have an estimated incidence of 1 in every 35,000 live births [2]. Based on the site of bony defect and protrusion, they are classified as follows: transethmoidal, Fig. 3 Intraoperative endoscopic images a The anterior part of mass in the nasal cavity (arrow) is adherent to the posterior septum b The inferior extent mass is visualized on lifting up the soft palate c A stitch is placed in the uvula for upward retraction to achieve satisfactory exposure d, e Final views, via the transnasal and transoral routes respectively, after careful dissection of the sac and resection at the extra-cranial neck (arrow) of the transsphenoidal encephalocele sphenoethmoidal, transsphenoidal, sphenomaxillary and sphenoorbital [1]. Several theories have been suggested to describe the embryogenesis of encephaloceles, including the incomplete closure of the neural tube causing herniation of meninge s and neural tissue [1] and a persistent craniopharyngeal canal [3]. Nevertheless, the aetiology remains poorly understood. As transsphenoidal encephaloceles are not clinically visible, the age of presentation is largely determined by the size of the encephalocele, related anomalies and presence or absence of respiratory difficulties. Signs and symptoms include upper airway obstruction, pulsatile mass, facial deformities such as hypertelorism or cleft lip, endocrine abnormalities, disruption of optic pathways and CSF leak with recurrent meningitis [4]. While the diagnosis is typically reached in the first year of life for patients with typical symptoms or during investigation of associated anomalies, those without characteristic facies may present only in adolescence or adulthood. Differential diagnosis for a nasal mass in a neonate includes nasal glioma, dermoid cyst or nasal polyp [4]. Nasal gliomas are encephaloceles that lack a direct intracranial connection

4 Fig. 4 a, b Postoperative sagittal MRI at 1 day and 3 months, respectively, demonstrating no evidence of recurrence of the nasal encephalocele with the suprasellar, sellar and sphenoidal components unchanged. The oronasopharyngeal airway is patent without an oropharyngeal airway and occur as firm, non-compressible masses within the nasal cavity [4]. In order to clinically distinguish these two entities, the Furstenberg test, which involves bilateral compression of the internal jugular veins, causes an encephalocele to enlarge due to its connection to the subarachnoid space but not a glioma. Dermoid cysts present as non-pulsatile, noncompressible masses with a dimple containing a hair follicle [4]. Nasal polyps are rare in children and usually associated with cystic fibrosis [4]. In our case, the diagnosis of a transsphenoidal encephalocoele was confirmed with both imaging and histological analysis. Imaging is fundamental for diagnosis, surgical planning and follow-up. CT scans allow evaluation of bone anatomy and the associated craniofacial skeleton defects. The anterior skull base in infants is incompletely ossified or unossified, and intravenous contrast is required to delineate the cartilaginous skull base [5]. MRI with gadolinium enhancement is useful to assess brain abnormalities and the contents of the encephalocele. This is crucial to identify vital structures in the sac such as the pituitary gland, hypothalamus, optic pathways and vessels of the circle of Willis before surgery [6]. Following careful analysis of our patient s preoperative imaging, we were able to tailor the safest approach and avoid damage to potentially significant structures. Consensus regarding treatment of transsphenoidal encephaloceles including the indication, timing and choice of surgical repair has yet to be established. Some surgeons do not recommend the correction of encephaloceles, believing that this would result in worsening morbidity and mortality [7]. Others advocate early intervention to decrease risk of infection, expansion of the mass and risk of injury to the herniated sac containing vital structures [8]. Strong indications for surgery include persistent CSF rhinorrhoea, recurrent meningitis, progression of neurological deficits and respiratory distress [7]. We believe that a transsphenoidal encephalocele causing respiratory and feeding difficulties in our patient, even as young as 48 days, warranted prompt surgical repair. Surgical approaches for transsphenoidal encephaloceles include transpalatal, transcranial which involves craniotomy, and endoscopic transnasal. The close relation of transsphenoidal encephaloceles with the hypothalamus, pituitary gland and optic pathway poses a surgical challenge, particularly in the paediatric population. Current literature shows that only the transpalatal technique has been utilized for children below 1 year of age [6, 8 10]. The endoscopic transnasal method is limited to older children and has never been described in infants. To our best knowledge, we report the youngest case of a combined endoscopic transnasal and transoral approach to a transsphenoidal encephalocele in a child. We believe that the endoscopic approach offers the distinct advantage of being suitable for infants with very small nasal and oral cavities, even in our 48-day-old patient. The endoscope allows wide-angled, closed-up views and effective visualization through a narrow surgical corridor. By using both nasal and oral spaces, we were able to achieve satisfactory access without resecting the turbinates or splitting the palate. Preservation of both inferior and middle turbinates maintains moisture of the nasal cavity, allows laminar flow of air through the nose and reduces postoperative crusting. Although the transpalatal technique provides good exposure, especially in cases with associated cleft palate, there may be difficulty in closure of the mucosal layer [8]. Additionally, splitting of the palate can result in delayed palatal wound healing, prolonged enteral tube feeding and velopharyngeal insufficiency [11]. We did not consider the transpalatal route because our patient did not have a cleft palate and we wanted to minimize the invasiveness of the procedure. Moreover, we attained adequate access with a Boyle Davis mouth gag and the placement of a stitch in the uvula for upward retraction. As for the transcranial subfrontal or pterional approach, this may prove to be challenge for a case of transsphenoidal encephalocele in view of the retrochiasmal location of the encephalocele as well as the proximity of the pituitary stalk. Apart from that, infants are more susceptible to retraction injuries with transcranial approaches due to incomplete myelination of the brain matter. It is important to establish that, unlike previous surgical strategies, our procedure does not reduce the entire herniated

5 sac into the intracranial cavity. The main priority is to safely remove the nasal component of the encephalocele to relieve our patient s symptoms of respiratory distress and permit feeding. The combined transnasal and transoral endoscopic approach with the aid of neuronavigation allows good demarcation of the extra-cranial neck of the transsphenoidal encephalocele. We were able to cauterize and carefully dissect the sac prior to excision. The defect of the neck was clearly visualized, and Valsalva manoeuvre was performed to exclude any CSF leak. In the event of CSF leak, an inlay tissue graft with bio-tissue glue can be applied. Our patient had an expedited recovery, tolerated full feeds by the second postoperative day and was discharged home within 4 days. Thus, we were able to achieve a satisfactory outcome and, yet, avoid aggressive surgical methods that could lead to devastating consequences, particularly in such a young child. Treatment of transsphenoidal encephaloceles is associated with postoperative complications such as palatal dehiscence, recurrence of encephalocele, CSF leak and meningitis. Deaths secondary to meningitis have been described in children treated via a transpalatal route [6, 9, 12]. We did not encounter any complications in our patient. However, continued follow-up is necessary to monitor for delayed CSF leak, hydrocephalus or recurrence of the encephalocele. Conclusion The surgical management of transsphenoidal encephalocele in neonates and infants is challenging. We describe a safe technique with low morbidity in managing such a condition. The combined endoscopic transnasal and transoral approach with neuronavigation is a minimally invasive, safe and feasible alternative, even for children below 1 year of age. Acknowledgments One of the authors of this paper, Vicknes Waran, is supported by University of Malaya s HIR-MOHE research grant initiative (H A000026). Conflict of interest interest. References The authors declare that they have no conflict of 1. Suwanwela C, Suwanwela N (1972) A morphological classification of sincipital encephalomeningoceles. J Neurosurg 36: Vannouhuys JM, Bruyn GW (1964) Nasopharyngeal transsphenoidal encephalocele, craterlike hole in the optic disc and agenesis of the corpus callosum. Pneumoencephalographic visualisation in a case. Psvchiat Neurol Neurochir 67: Mood GF (1938) Congenital anterior herniations of brain. Ann Otol Rhinol Laryngol 47: Tirumandas M, Sharma A, Gbenimacho I, Shoja MM, Tubbs RS, Oakes WJ, Loukas M (2013) Nasal encephaloceles: a review of etiology, pathophysiology, clinical presentations, diagnosis, treatment, and complications. Childs Nerv Syst 29: Rahbar R, Resto VA, Robson CD, Perez-Atayde AR, Goumnerova LC, McGill TJ, Healy GB (2003) Nasal glioma and encephalocele: diagnosis and management. Laryngoscope 113: Raman Sharma R, Mahapatra AK, Pawar SJ, Thomas C, Al-Ismaily M (2002) Trans-sellar trans-sphenoidal encephaloceles: report of two cases. J Clin Neurosci 9: Abe T, Lüdecke DK, Wada A, Matsumoto K (2000) Transsphenoidal cephaloceles in adults. A report of two cases and review of the literature. Acta Neurochir (Wien) 142: Formica F, Iannelli A, Paludetti G, Di Rocco C (2002) Transsphenoidal meningoencephalocele. Childs Nerv Syst 18: Rathore YS, Sinha S, Mahapatra AK (2011) Transsellar transsphenoidal encephalocele: a series of four cases. Neurol India 59: Steven RA, Rothera MP, Tang V, Bruce IA (2011) An unusual cause of nasal airway obstruction in a neonate: trans-sellar, trans-sphenoidal cephalocoele. J Laryngol Otol 125: Sinha S, Mirza S, Bishop N, Zaki H, McMullan J (2012) Endoscopic endonasal resection of the odontoid peg for paediatric basilar invagination. Br J Neurosurg 26: Mahapatra AK, Suri A (2002) Anterior encephalocele: a study of 92 cases. Pediatr Neurosurg 36: