|Ahead of print
Mask ventilation in frontonasal meningoencephalocele: Case report
Shipra Verma, Konish Biswas, Sanjay Agrawal, Roshan Andleeb
Department of Anaesthesiology, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India
|Date of Submission||18-Oct-2020|
|Date of Acceptance||26-Jan-2021|
|Date of Web Publication||19-Jul-2021|
Department of Anaesthesiology, All India Institute of Medical Sciences, Rishikesh 249203, Uttarakhand.
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Frontonasal encephalocele is a rare anatomical variant of the meningoencephalocele. Peri-operative anesthesia concerns involve anticipated difficult mask ventilation as well as surgical complications such as compression and rupture of meningoencephalocele. The compression of encephalocele is associated with raised intracranial pressure (ICP) and even rupture of overlying skin leading to cerebrospinal fluid leak, hemorrhage, exposure of underlying frontal lobe, meningitis, seizures, and even death. We report a case of 6-year-old female presenting with rare variant of frontonasal encephalocele for bifrontal craniotomy, excision of encephalocele, and repair. Difficult mask ventilation was anticipated, and patient airway was managed with use of size 4 anatomical mask.
Keywords: Case report, frontonasal meningoencephalocele, mask ventilation
| Introduction|| |
Meningoencephalocele is a rare neural tube defect characterized by protrusion of the brain, cerebrospinal fluid (CSF), and overlying leptomeninges through a cranial defect. The frontal bone is a less common location of meningoencephalocele, and the frontonasal variety represents a rare anatomical subtype of the same. In frontonasal meningoencephalocele, cranial contents herniate from the junction of frontal and nasal bones and appear at the root of the nose. Difficult mask ventilation is always a concern in such cases owing to the location of pathology. We describe the airway management in a case of frontonasal meningoencephalocele associated with cerebellar tonsillar ectopia posted for bifrontal craniotomy and excision of encephalocele.
| Case Report|| |
A 6-year-old female patient weighing 20 kg was admitted in neurosurgery with a complaint of painless swelling measuring 3.5 cm × 4 cm in the glabellar region and extending till the nasal alae [Figure 1]A and B. It was present since birth, gradually increasing to achieve present size, soft in consistency with multiple nodular growths on the overlying skin. The swelling increased in size on coughing. On clinical examination, neurological deficit, vision impairment, mental retardation, or delayed developmental milestones were absent. Imaging revealed a midline defect in frontal bone with herniation of bilateral frontal lobes with CSF-filled meningeal sac [Figure 1]C and associated cerebellar tonsillar ectopia with 16 mm descent into the foramen magnum and corpus callosum agenesis. A diagnosis of frontonasal meningoencephalocele associated with cerebellar tonsillar ectopia was made. The child was taken up for bifrontal craniotomy and excision of encephalocele under general anesthesia.
|Figure 1: (A and B) Glabellar swelling extending till nasal alae; (C) MRI brain—midline defect and herniation; (D) mask ventilation with size 4 mask|
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The child was kept nil per oral 8 h for solid and 2 h for clear fluid before surgery. Preoperative intravenous cannulation was established with a 22G cannula. Preoperatively difficult mask ventilation was expected due to the location of meningoencephalocele. In the usual clinical practice size, two anatomical face masks (Draeger) would be appropriate for this age and weight of the patient. Use of small size mask could be associated with an improper seal as well as a risk of compression of meningoencephalocele, whereas a too-large face mask would be associated with air leak. We tried a size 4 anatomical mask (Draeger) on the face contour of the patient and found it to have adequate fit, covering the swelling without compression as well as providing an adequate seal. The difficult airway cart was kept ready.
The patient was pre-oxygenated with 100% oxygen to achieve an end-tidal oxygen concentration of 95. Induction of anesthesia was achieved with fentanyl 2 μg/kg and propofol 1 mg/kg; mask ventilation with size 4 anatomical mask was tried and found to be adequate [Figure 1D]. Muscle relaxation was achieved with suxamethonium 2 mg/kg and mask ventilation continued. Suxamethonium was preferred over non-depolarizing muscle relaxants to decrease the time for mask ventilation. Adequate ventilation with a square wave capnograph was obtained. The patient was intubated with a cuffed endotracheal tube of size 5.5 with minimal head extension, as compression of downward displaced cerebellar tonsil was a possibility. Anesthesia was maintained with 50% oxygen in the air, sevoflurane (0.6–0.8 MAC), and an intermittent bolus of vecuronium and fentanyl. Normocapnia was maintained throughout the procedure. The child was covered with a warm blanket to maintain normothermia. The patient underwent surgery for 4 h. Blood losses were replaced with crystalloids and blood products. There were no signs of brainstem compression at any time in the peri-operative period. The intraoperative course was uneventful and the patient was successfully extubated after surgery. Oxygen supplementation in the immediate postoperative care unit was maintained with a nasal cannula with a flow of 2 L/min. Postoperative recovery of the patient was uneventful and the patient was discharged home 14 days after surgery.
| Discussion|| |
In frontonasal meningoencephalocele, the prime concern is difficult to mask ventilation with the possibility of compression/rupture of encephalocele. In our case, we utilized a larger facemask, which adequately covered the mouth, nose, and swelling. This was possible because our patient was older and having an oblong swelling. Increased anatomical dead space was a concern but we were able to overcome the use of high oxygen flow and a slight increase in minute ventilation. We could also consider rapid sequence intubation to avoid mask ventilation. In that case, pre-oxygenation could be performed with high flow nasal cannula. The unavailability of high flow nasal cannula in our operation theater at that time excluded this choice.
Previously, a case series of 133 patients of anterior encephalocele reported an incidence of 12 cases of frontonasal encephalocele. Presentation of this variant had been infrequently reported in the surgical literature. Few case reports are available on airway management in frontonasal meningoencephalocele., Mahajan and Rath have successfully managed a case of frontonasal meningoencephalocele with the use of a smaller pediatric round mask which helped them in attaining a proper seal.
The compression of encephalocele is associated with raised ICP and even rupture of overlying skin leading to CSF leak, hemorrhage, exposure of the underlying frontal lobe, meningitis, seizures, and even death. Peri-operative concerns of cerebellar tonsillar ectopia include risk of aspiration; brainstem compression, raised ICP, and seizures were also kept in mind. Taking due consideration of all the above factors, the peri-operative course of this patient passed uneventfully.
We conclude that patients with this facial dysmorphism pose a challenge to the anesthesiologist with facemask ventilation during induction of general anesthesia. We propose that a relatively large size facemask, which adequately covers the mouth, nose, and the swelling without compression on encephalocele and globes, can be employed as a safe strategy for facemask ventilation. A difficult airway cart should always be kept ready during airway management in the patient with frontonasal meningoencephalocele.
Declaration of Patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
No potential conflicts of interest relevant to this article were reported.
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