ABSTRACT AND ANATOMY
There are so many facial paralysis occurring in almost every part of the world with unknown reason. The real prevalence of the disease is not exact in numbers because many patients hide themselves from the community. Facial paralysis, even incomplete is a highly bothering condition. I treated an acoustic neuroma operated patient in the past, she was isolated herself from family, and was almost committing suicide.
In my experience Bell’s Palsy or other some known/some unknown causes of sudden facial paralysis, most probably occure because of increased pressure in the narrow facial canal. As known this canal is composed of three parts depending on its direction. Depending on the anatomic details of each person the labyrinthine segment is the narrowest segment 1. The facial nerve occupies up to 83% of the labyrinthine canal cross-sectional area compared with only 64% of the more distal mastoid area 2. The junction of the labyrinthine and tympanic components of the fallopian canal is formed by an acute angle, and shearing of the facial nerve commonly occurs as the nerve traverses this genu. Tympanic or horizontal portion is also a narrow part of the canal and also has genu while becoming a vertical portion.
Facial nerve travels in its canal (fallopian canal) is protected in a nerve sheet named epineurium. This involves group of axons covered by endoneurium, group of axons covered by perineurium is called fascicles.
THEORY AND PROPOSAL
As described in the anatomy the narrowest part (labyrinthine segment) looks more prone to compression. But before the petrosal nerves exit, this segment contains more fasciciles, and axons. The edema liquid drains from a higher pressure throughout a lower pressure in the epineurium. This shows us to make the decompression from 2nd genu to vertical segment.
In my 25 years clinical experience showed me that when a drainage and anti-edema treatment is applied, the recovery became more in number of patients. Also this treated patients had less complications like synkinesis, unfunctional mimic muscle so on…
I am personally applying transmastoid 2nd genu to stylomastoid foramen decompression by doing a posterior tympanotomy. This also allows us to protect the hearing. I have great results in 4-5 months non recovered total axonal degenerations, even in selected patients performing same procedure in late paralysis also. I can not give a large series but I belive in every unknown facial paralysis incuding Bell’s palsy, the nerve should be decompressed ASAP for guarantie recovery, most important besides recovery protect patients from false recovery like synkinesis etc.
My proposal is to make a prospective study with interested collegues. Make 3 group of patients. One study group that do not accept any medication, one accepts chemical antiedema treatment, the third group accepting early transmastoid decompression surgery.
I belive this study will change our views on management of face paralysis with unknown cause deeply.
- Terence M. Myckatyn, M.D., Susan E. Mackinnon, M.D.. A Review of Facial Nerve Anatomy. SEMINARS IN PLASTIC SURGERY/VOLUME 18, NUMBER 1 2004
- Fisch U, Esslen E. Total intratemporal exposure of the facial nerve. Pathologic findings in Bell’s palsy. Arch Otolaryngol 1972;95:335–341