gms | German Medical Science

Nasocerebral fistulas are rare malformations of the brigde of the nose. These malformations have a possibility of a direct communication between the extra- and intracranial space. An inconspicuous fistula on the brigde of the nose a so called neuroporus usually is the only clinical finding.

These fistulae can manifest,the adult age at first time [Ref. 5], [Ref. 15] in the early childhood [Ref. 3], [Ref. 9]. There are different expression forms of this malformation [18].

As a typical symptom a so called Neuroporus can found in the area of the bridge of the nose. This is the outer fistula opening which represents himself on the bridge of the nose as a small change of the skin coloring with the outer fistula opening. The fistula can be found subcutaneously through the Synostose between the two ossa nasalia and the cartilage part of the bridge of the nose to the Crista galli, where it can end in a cyst formation [Ref. 1].

The 3-year-old patient was seen with an inflammation in the medial eye angle on the left eye 2003. At the clinical examination a Hypertelorismus was found. A surgeon had resected a little fistula at the bridge (e.g. neuroporus, Figure 1 [Fig. 1]) of the nose 3 months before. After eight weeks the patient developed an increasing swelling and inflammation in the medial angle of the left eye (Figure 2 [Fig. 2]). In the MRI-scans we could find an fistula from the bridge of the nose to the endocranial space with an inflammatory reaction of the dura and the base of the frontal brain (Figure 3 [Fig. 3]).

There was no clinical sign of a meningitis. An interdisciplinarry operation of neurosurgeon and ENT-surgeon was carried out. At first the endocranial part was resected by the neurosurgeon over a bicoronarially approach. An epidural abscess and an epidermoid were found with in inflammation of the surrounding dura. Than the ENT-surgeon resected the fistula upfrom the scull base to the brigde of the nose through its way between the two ossa nasalia. The reconstructon of the scull base was done with a galea-periost-flap and a split graft of the tabula externa.

The patient is free of residual disease for 32 months.

The 2-year-old patient was seen with an 2 months history of a swelling of the medial angle of the left eye. A Hypertelorismus was found at the clinical examination also here. The MRI-scans showed a cystic tumor on the left in the medial angle of the left eye with a fistula to the Crista galli. The septum nasale couldn`t find on its right place. The operative therapy carried out interdisciplinarily in the same way like the first patient in a common operation of neurosurgeon and ENT. We found a part of cartilage in the region of the christa galli with a fistula to the brigde of the nose and an absence of the cartilage part of the septum nasale. We interpreted this cartilage formation as embryological residium of the cartilage of the nasal septum. The reconstruction of the scull base was done with a galea-periost-flap. The patient was observed over 28 months without any problems.

Nasocerebral fistula are rare malformations in the area of the bridge of the nose in which a direct communication between the skin and the endocranial space is possible [Ref. 6]. Variations of the expression are from a present neuroporus up to fistula to the endocranium [Ref. 11], [Ref. 14].

Typically is the so called Neuroporus in the area of the bridge of the nose (Figure 1 [Fig. 1]).

It can only be a small difference in the skin color around the outer opening of the fistula at the connecting part between the cartilagical and ossicular part of thebridge of the nose [Ref. 8], [Ref. 11]. In our opinion such a Neuroporus always should be a reason to carry out a MRI-scan to investigate the extension of this malformation in every surgical therapy.

Therefore in our opinion a MRI-scan is indicated [Ref. 3] in all cases of this at suspicion on a missing formation in the area of the bridge of the nose in form of the MRT in front of every surgical manipulation. Representations in the CISS technology and after contrast medium permit one better differentiation. If uncertainties should result, however, with regard to the bone changes in connection with the fistula, a CT should be done [Ref. 12].

The interdisciplinary operation of neurosurgeon and ENT-surgeon is the best way of therapy in our opinion. The endocranial part can be resected over a bicoronal transcranial procedure. As second step the ENT-specialist due the resection of the extracranial part.

An open Rhinoplastik [Ref. 2] or a trancolumellares alternatively is recommended to procedures [Ref. 10], [Ref. 2] as an operative entrance. However, a clearly worse overview passes at these surgical entrances in the fistula course under the bridge of the nose and over the endocraniial part with an increased risk for endocranial complications directly so that we wouldn't recommend these entrances despite the lower operative trauma and risk.

Small discoloration of the skin in the bridge of the nose with small fistulae in children may be the only signs of a nasocerebral fistula. In any case of suspicion of such a malformation an MRI is mandatory. The interdisciplinary approach via bifrontal craniotomy and small transfacial approaches should be the therapy. The chosen approach in treatment offered the best functional and cosmetic results.