PMC9902083_01
An intraoperative endoscopic image. The herniated brain tissue into ethmoidal sinus was delineated with a yellow dotted line. LP, lamina papyracea; MS, maxillary sinus.
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However, the operation was terminated immediately after herniated brain tissue was identified on frozen biopsy during ethmoidectomy ( Fig. 1 ).
Coronal and sagittal computed tomography scans (
A
,
B
) before and (
C
,
D
) after surgery. The white arrows indicate the focal bony defect of the left anterior cranial base (
A
,
B
). The white arrow heads indicate the split calvarial bone graft fixed with screw fixation (
C
,
D
).
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Preoperative computed tomography (CT) showed a focal bony defect in the left anterior cranial base, which was considered insignificant ( Fig. 2A and B ). A 1 x 1cm-sized split calvarial graft was placed over the cranial base defect and fixed using a 6-mm-sized titanium screw ( Fig. 2C and D ).
Preoperative coronal T2-weighted magnetic resonance images demonstrating interval progress of the meningoencephalocele in the fronto-ethmoid-maxillary sinus. (
A
) 10 years prior, when the meningoencephalocele was first observed, and (
B
) before reconstruction of the anterior cranial base.
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After surgery, brain magnetic resonance imaging (MRI) confirmed meningoencephalocele in the left frontal-ethmoid sinus and nasal cavity ( Fig. 3A ). The interval progress of the meningoencephalocele into the left fronto-ethmoid-maxillary sinus was observed on 10-year follow-up brain MRI ( Fig. 3B ).
Intraoperative photographs of the anterior skull base. (
A
) Through bifrontal craniotomy, the skull base defect was identified after removal of the meningoencephalocele. (
B
) The pericranial flap (indicated with an asterisk) was transferred for dural repair. Ant, anterior; Post, posterior; Mid, midline.
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A 6 x 8 mm-sized cranial defect was identified in the left anterior skull base ( Fig. 4A and B ).
Sagittal and top-down endocranial views in three-dimensional renderings from computed tomography scans (
A
,
B
) before and (
C
,
D
) after surgery. The anterior cranial base defect (delineated with a blue dotted line,
B
) was reconstructed with a split calvarial bone graft (delineated with a blue dotted line,
D
). Additionally, secondary frontal advancement was performed (
C
,
D
).
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Three pieces of 1 x 6 cm-sized split calvarial grafts were inserted into the coronal gap between the bifrontal bone flap and the parietal bones ( Fig. 5 ).
Frontal and lateral profile photographs of the patient (
A
,
B
) before and (
C
,
D
) 1 year after secondary frontal advancement. Note the improvement in the contour of the forehead.
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There were no recurrences of meningoencephalocele or any symptoms at the 2-year follow-up ( Fig. 6 ).