TECHNICAL NOTE

Combined transnasal and transoral endoscopic approachto 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

AbstractPurpose This paper reports an unusual case of a transsphenoidalencephalocele and discusses our experience with a minimallyinvasive management. To the best of our knowledge, we presentthe first case of a combined endoscopic transnasal and transoralapproach to a transsphenoidal encephalocele in an infant.Methods A 17-day-old boy, whowas referred for further assess-ment of upper airway obstruction, presented with respiratorydistress and feeding difficulties. Bronchoscopy and imaging re-vealed a transsphenoidal encephalocele. At the age of 48 days, heunderwent a combined endoscopic transnasal and transoral exci-sion of the nasal component of the encephalocele. This approach,with the aid of neuronavigation, allows good demarcation of theextra-cranial neck of the transsphenoidal encephalocele.Wewereable to cauterize and carefully dissect the sac prior to excision.The defect of the neck was clearly visualized, and Valsalva ma-noeuvre was performed to exclude any CSF leak. As the defectwas small, it was allowed to heal by secondary intention.Results The patient’s recovery was uneventful, and he toler-ated full feeds orally on day 2. Postoperative imaging demon-strated no evidence of recurrence of the nasal encephalocele.Endoscopic follow-up showed good healing of the mucosaand no cerebrospinal fluid leak.Conclusions The surgical management of transsphenoidalencephalocele in neonates and infants is challenging. We de-

scribe a safe technique with lowmorbidity in managing such acondition. The combined endoscopic transnasal and transoralapproach with neuronavigation is a minimally invasive, safeand feasible alternative, even for children below 1 year of age.

Keywords Transsphenoidal encephalocele . Endoscopy .

Transnasal . Transoral . Paediatric

Introduction

Basal encephalocele is an uncommon congenital malforma-tion in which the intracranial structures herniate through adefect in the skull base. The transsphenoidal encephaloceleis the rarest subtype with an incidence of approximately 1 in70,000 live births and represents 5 % of basal encephaloceles[1]. This paper aims to report an unusual case of atranssphenoidal encephalocele causing upper airway obstruc-tion and to discuss our experience with a minimally invasivemanagement. To the best of our knowledge, we present thefirst case of a combined endoscopic transnasal and transoralapproach to a transsphenoidal encephalocele in an infant.

Case report

A 17-day-old boy was transferred to our tertiary referral centrefor further assessment of upper airway obstruction. He wasborn at term via vacuum-assisted delivery following an un-eventful pregnancy. There was no facial dysmorphism, cleftlip or cleft palate. Examination revealed a grade 2/6pansystolic murmur at the left sternal edge, and echocardio-gram reported a tiny patent foramen ovale, small secundumatrial septal defect, small ventricular septal defect and mild leftpulmonary artery stenosis.

S. H. Tan (*) :A. M. Manuel :N. PrepageranDepartment of Otolaryngology, Faculty of Medicine, UniversityMalaya, Lembah Pantai, 50603 Kuala Lumpur, Malaysiae-mail: sienic@yahoo.com

K. S. Mun : P. A. ChandranDepartment of Pathology, Faculty of Medicine, University Malaya,Lembah Pantai, 50603 Kuala Lumpur, Malaysia

V. Waran :D. GanesanDepartment of Neurosurgery, Faculty of Medicine, UniversityMalaya, Lembah Pantai, 50603 Kuala Lumpur, Malaysia

Childs Nerv SystDOI 10.1007/s00381-015-2667-9

On day 4, he developed intermittent stridor withsuprasternal and subcostal recessions. Worsening respiratorydistress was noted on day 14, and oral intubation was per-formed. Although he was extubated 2 days later, he requiredcontinuous positive airway pressure ventilation. He was onlyable to maintain satisfactory saturation levels on room air withan oropharyngeal airway. A nasogastric tube was also insertedfor nutrition, as he encountered feeding difficulties.

Bronchoscopy demonstrated a large nasopharyngeal masswith a smooth surface obstructing 90 % of the airway. Theremainder of the upper airway was unremarkable. Magneticresonance imaging (MRI) revealed a midline soft tissue masswhich did not enhance with contrast and consisted of mainlydysplastic brain tissue without significant vital structures. Themass extended from the suprasellar space through the body ofthe sphenoid bone into the nasopharyngeal, nasal and oropha-ryngeal cavities, thus confirming a transsphenoidalencephalocele (Fig. 1a). Computed tomography (CT) showeda potential defect at the sphenoid bone about 0.4 cm in diam-eter 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 radiolucentcartilaginous bone that forms the skull base can appear as adefect on a CT scan (Fig. 1b).

Preoperatively, his ophthalmological and endocrinologicalexaminations were unremarkable. Nasopharyngeal culturedemonstrated Pseudomonas aeruginosa, but there was no clin-ical evidence of sepsis, meningitis or cerebrospinal fluid (CSF)leak. However, in view of his planned surgery, he was treatedwith antibiotics and his repeat culture showed normal flora.

At the age of 48 days, he underwent a combined endoscop-ic transnasal and transoral excision of the nasal component ofthe encephalocele. Histopathological examination showed awell-circumscribed nodule composed of nests of glial tissue,separated by bands of fibrous tissue, covered by stratifiedsquamous epithelium (Fig. 2a). The glial tissue was made up

of astrocytes and oligodendrocytes (Fig. 2b), which were im-munoreactive to glial fibrillary acid protein (GFAP). Scatteredforeign body-type multinucleated giant cells (CD68 positive)and a few hemosiderin-laden macrophages were also present.

Hence, based on the histological findings and the radiolog-ical appearance of herniation of intradural cranial content intothe nasopharynx, the diagnosis of a nasal (transsphenoidal)encephalocele was concluded. The differential diagnosis of ahypothalamic hamartoma, which had herniated, was also tak-en into consideration but deemed less likely.

Surgical technique

The patient was positioned supine and registered to theMedtronic AxiEM™ electromagnetic navigation systemusing the MRI images. Rigid-rod endoscopes, with lenses of2.7 and 4 mm in diameter, were mounted on a digital videocamera system (Karl Storz). His nasal passages were preparedwith Moffat’s solution (1 ml of 1:1000 adrenaline, 2 ml of10 % cocaine and 4 ml of 8.4 % sodium bicarbonate).

First, we assessed the extent of the nasopharyngeal mass byadvancing the 0° endoscope into the nasal cavity, followed bythe 30° endoscope into the oral cavity. The mass was adherentanteriorly to the posterior septum and superoposteriorly tothe roof of the nasopharynx (Fig. 3a and b). Next, we achievedgood exposure of the oropharynx with a Boyle Davis mouthgag and a stitch placed in the uvula for upward retraction(Fig. 3c). The bilateral middle and inferior turbinates and softpalate were preserved.

Using the transnasal approach initially, we resected theanterior attachment of the lesion with monopolar cauteriza-tion. We then employed a transoral approach to carefully cau-terize 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 rem-nant via the nasal cavity (Fig. 3d and e). Valsalva manoeuvre

Fig. 1 a Preoperative sagittal MRI revealing a midline soft tissue massconsisting ofmainly dysplastic brain tissue extending from the suprasellarspace 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 thenasopharyngeal wall b Preoperative coronal CT scan showing a potentialdefect at the sphenoid bone about 0.4 cm in diameter through which theencephalocele has herniated

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was then performed to ensure that there was no intraoperativeCSF leak. As the defect was small, it was allowed to heal bysecondary intention.

Postoperative course

The patient was extubated after surgery, and recovery wasuneventful with no signs of respiratory distress, CSF leak ormeningitis. He was tolerating full feeds orally on day 2 anddischarged well on day 4. Serial postoperative MRI scansdemonstrated no evidence of recurrence of the nasalencephalocele with the suprasellar, sellar and sphenoidal com-ponents unchanged (Fig. 4). Endoscopic follow-up showedgood healing of the mucosa and no CSF leak.

Discussion

Basal encephaloceles have an estimated incidence of 1 in ev-ery 35,000 live births [2]. Based on the site of bony defect andprotrusion, they are classified as follows: transethmoidal,

sphenoethmoidal, transsphenoidal, sphenomaxillary andsphenoorbital [1]. Several theories have been suggested todescribe the embryogenesis of encephaloceles, including theincomplete closure of the neural tube causing herniation ofmeninges and neural t issue [1] and a persis tentcraniopharyngeal canal [3]. Nevertheless, the aetiology re-mains poorly understood.

As transsphenoidal encephaloceles are not clinically visi-ble, the age of presentation is largely determined by the size ofthe encephalocele, related anomalies and presence or absenceof respiratory difficulties. Signs and symptoms include upperairway obstruction, pulsatile mass, facial deformities such ashypertelorism or cleft lip, endocrine abnormalities, disruptionof optic pathways and CSF leak with recurrent meningitis [4].While the diagnosis is typically reached in the first year of lifefor patients with typical symptoms or during investigation ofassociated anomalies, those without characteristic facies maypresent only in adolescence or adulthood.

Differential diagnosis for a nasal mass in a neonate includesnasal glioma, dermoid cyst or nasal polyp [4]. Nasal gliomasare encephaloceles that lack a direct intracranial connection

Fig. 2 a The well-circumscribednodule is covered by stratifiedsquamous epithelium (H & E,original magnification!20) b Thestroma is composed of benignfibrillary neural tissue which waspositive for glial fibrillary acidicprotein (H & E, originalmagnification!100)

Fig. 3 Intraoperative endoscopicimages a The anterior part ofmass in the nasal cavity (arrow) isadherent to the posterior septum bThe inferior extent mass isvisualized on lifting up the softpalate c A stitch is placed in theuvula for upward retraction toachieve satisfactory exposure d, eFinal views, via the transnasal andtransoral routes respectively, aftercareful dissection of the sac andresection at the extra-cranial neck(arrow) of the transsphenoidalencephalocele

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and occur as firm, non-compressible masses within the nasalcavity [4]. In order to clinically distinguish these two entities,the Furstenberg test, which involves bilateral compression ofthe internal jugular veins, causes an encephalocele to enlargedue to its connection to the subarachnoid space but not aglioma. Dermoid cysts present as non-pulsatile, non-compressible masses with a dimple containing a hair follicle[4]. Nasal polyps are rare in children and usually associatedwith cystic fibrosis [4]. In our case, the diagnosis of atranssphenoidal encephalocoele was confirmed with both im-aging and histological analysis.

Imaging is fundamental for diagnosis, surgical planningand follow-up. CT scans allow evaluation of bone anatomyand the associated craniofacial skeleton defects. The anteriorskull base in infants is incompletely ossified or unossified, andintravenous contrast is required to delineate the cartilaginousskull base [5]. MRI with gadolinium enhancement is useful toassess brain abnormalities and the contents of theencephalocele. This is crucial to identify vital structures inthe sac such as the pituitary gland, hypothalamus, optic path-ways and vessels of the circle of Willis before surgery [6].Following careful analysis of our patient’s preoperative imag-ing, we were able to tailor the safest approach and avoid dam-age to potentially significant structures.

Consensus regarding treatment of transsphenoidalencephaloceles including the indication, timing and choiceof surgical repair has yet to be established. Some surgeonsdo not recommend the correction of encephaloceles, believingthat this would result in worsening morbidity and mortality[7]. Others advocate early intervention to decrease risk ofinfection, expansion of the mass and risk of injury to theherniated sac containing vital structures [8]. Strong indicationsfor surgery include persistent CSF rhinorrhoea, recurrent men-ingitis, progression of neurological deficits and respiratorydistress [7]. We believe that a transsphenoidal encephalocelecausing respiratory and feeding difficulties in our patient, evenas young as 48 days, warranted prompt surgical repair.

Surgical approaches for transsphenoidal encephaloceles in-clude transpalatal, transcranial which involves craniotomy,

and endoscopic transnasal. The close relation oftranssphenoidal encephaloceles with the hypothalamus, pitui-tary gland and optic pathway poses a surgical challenge, par-ticularly in the paediatric population. Current literature showsthat only the transpalatal technique has been utilized for chil-dren below 1 year of age [6, 8–10]. The endoscopic transnasalmethod is limited to older children and has never been de-scribed in infants. To our best knowledge, we report the youn-gest case of a combined endoscopic transnasal and transoralapproach to a transsphenoidal encephalocele in a child.

We believe that the endoscopic approach offers the distinctadvantage of being suitable for infants with very small nasaland oral cavities, even in our 48-day-old patient. The endo-scope allows wide-angled, closed-up views and effective vi-sualization through a narrow surgical corridor. By using bothnasal and oral spaces, we were able to achieve satisfactoryaccess without resecting the turbinates or splitting the palate.Preservation of both inferior and middle turbinates maintainsmoisture of the nasal cavity, allows laminar flow of air throughthe nose and reduces postoperative crusting.

Although the transpalatal technique provides good expo-sure, especially in cases with associated cleft palate, there maybe difficulty in closure of the mucosal layer [8]. Additionally,splitting of the palate can result in delayed palatal woundhealing, prolonged enteral tube feeding and velopharyngealinsufficiency [11]. We did not consider the transpalatal routebecause our patient did not have a cleft palate and we wantedto minimize the invasiveness of the procedure. Moreover, weattained adequate access with a Boyle Davis mouth gag andthe placement of a stitch in the uvula for upward retraction.

As for the transcranial subfrontal or pterional approach, thismay prove to be challenge for a case of transsphenoidalencephalocele in view of the retrochiasmal location of theencephalocele as well as the proximity of the pituitary stalk.Apart from that, infants are more susceptible to retractioninjuries with transcranial approaches due to incompletemyelination of the brain matter.

It is important to establish that, unlike previous surgicalstrategies, our procedure does not reduce the entire herniated

Fig. 4 a, b Postoperative sagittalMRI at 1 day and 3 months,respectively, demonstrating noevidence of recurrence of thenasal encephalocele with thesuprasellar, sellar and sphenoidalcomponents unchanged. Theoronasopharyngeal airway ispatent without an oropharyngealairway

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sac into the intracranial cavity. The main priority is to safelyremove the nasal component of the encephalocele to relieveour patient’s symptoms of respiratory distress and permit feed-ing. The combined transnasal and transoral endoscopic ap-proach with the aid of neuronavigation allows good demarca-tion of the extra-cranial neck of the transsphenoidalencephalocele. We were able to cauterize and carefully dissectthe sac prior to excision. The defect of the neck was clearlyvisualized, and Valsalva manoeuvre was performed to excludeany CSF leak. In the event of CSF leak, an inlay tissue graftwith bio-tissue glue can be applied.

Our patient had an expedited recovery, tolerated full feedsby the second postoperative day and was discharged homewithin 4 days. Thus, we were able to achieve a satisfactoryoutcome and, yet, avoid aggressive surgical methods thatcould lead to devastating consequences, particularly in sucha young child.

Treatment of transsphenoidal encephaloceles is associatedwith postoperative complications such as palatal dehiscence,recurrence of encephalocele, CSF leak and meningitis. Deathssecondary to meningitis have been described in children treat-ed via a transpalatal route [6, 9, 12]. We did not encounter anycomplications in our patient. However, continued follow-up isnecessary to monitor for delayed CSF leak, hydrocephalus orrecurrence of the encephalocele.

Conclusion

The surgical management of transsphenoidal encephalocele inneonates and infants is challenging. We describe a safe tech-nique with low morbidity in managing such a condition. Thecombined endoscopic transnasal and transoral approach withneuronavigation is a minimally invasive, safe and feasiblealternative, even for children below 1 year of age.

Acknowledgments One of the authors of this paper, Vicknes Waran, issupported byUniversity ofMalaya’s HIR-MOHE research grant initiative(H-50001-00-A000026).

Conflict of interest The authors declare that they have no conflict ofinterest.

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