Management of CSF Leak After Vestibular Schwannoma Surgery

Abstract

To the Editor We have read with great interest the article entitled “Management of Cerebrospinal Fluid Leaks After Vestibular Schwannoma Surgery,” by Mangus et al. (1). We would like to congratulate the authors for their valuable contribution to the relevant literature. Cerebrospinal fluid (CSF) leak is still the most common and challenging complication of vestibular schwannoma surgery, and despite multiple articles suggesting solutions for this problem, it is still a frequent encountered drawback, sometimes at unacceptable high rates. The authors state that postoperative CSF leak rates reported in the literature range from 2% to 30%. Surprisingly, three publications of our group with 0%, 1.4%, and 0.8% CSF leakage are not taken into account (2–4). In this study the authors reported an overall incidence CSF leak of 12.9%. However, if we consider changes in rates over time, we notice that CSF leak rate dropped down from 27% to 6%. We agree with the sentence that this downward trend is consistent with the introduction of abdominal fat graft and modifications in closure techniques, but it would have been worthy to detail the different steps of their closure technique. Indeed, we believe that the main reasons of variation of CSF leak rates in the literature are factors related to surgical technique rather than patient variables. It is stated in this study that authors use fat and muscle grafts for Eustachian tube and middle ear space obliteration in a translabyrinthine approach. Although appealing, muscle graft tends to atrophy, whereas fat graft tends to dissolve on contact with air, which could lead to delayed rhinorrhea. Packing the middle ear cleft with dry periosteum collected at the beginning while drilling the mastoid seems more successful. Up to 1993, the overall incidence of CSF leak in our institution was 6.9%. Given this significant high rate, we decided to modify our closure technique in an attempt to lower its occurrence. In translabyrinthine approach, all air cells should be inspected especially at the level of facial and subfacial recesses, and patent ones must be sealed using bone wax. Next, incus is removed through the aditus, taking care not to dislocate the stapes to avoid CSF leakage through the oval window. Middle ear cleft is then packed with previously collected dry periosteum, which prevents later occurrence of rhinoliquorrhea. At the end, thin and long autologous fat strips are carefully introduced deep in the cerebellopontine angle, and the musculofascial layer is sutured in a watertight manner adding to the seal against leakage. As a result, the incidence dramatically dropped down to less than 1% and still unchanged since (4). Further evidence of the success of this technique is supported by Mamikoglu et al. (5) and Hardy et al. (6) showing a reduction of CSF leak in enlarged traslabyrinthine approach, from 17% to 2.3% and from 13% to 1.6%, respectively (also these 2 last articles have not been cited). The similar concept, by isolating the middle ear from the surgical field, also has been successfully adopted in retrosigmoid approach (7), with an improvement of the CSF rate from 21.4% to 1.8%. Mehdi Ben Ammar, M.D. Department of Neurosurgery Military Hospital of Tunis University of Tunis El Manar Tunisia Paul Merkus, M.D., Ph.D. Department of Otorhinolaryngology-Head and Neck Surgery VU University Medical Center Amsterdam, The Netherlands Filippo Di Lella, M.D., Ph.D. Mario Sanna, M.D. Gruppo Otologico Piacenza Roma, Italy