Microsurgery
In 333 patients after microsurgery (Koos grading scale 1: 12, grade 2: 34, grade 3: 62, and grade 4: 225) permanent trigeminal nervedysfunction was found in 1% 1).
In large/compressive, trigeminal nerve deficit has to be sought to avoid corneal complications in particular. Trigeminal hypoesthesia occurs preoperatively in about half of the cases. It remains relatively stable after tumor removal, but there appears to be an increased rate of absentcorneal reflex and neurotrophic keratitis postoperatively. Karkas et al. were able to correlate pre/postoperative trigeminal hypoesthesia with pre/postoperative MRI findings 2).
In large/compressive, trigeminal nerve deficit has to be sought to avoid corneal complications in particular. Trigeminal hypoesthesia occurs preoperatively in about half of the cases. It remains relatively stable after tumor removal, but there appears to be an increased rate of absentcorneal reflex and neurotrophic keratitis postoperatively. Karkas et al. were able to correlate pre/postoperative trigeminal hypoesthesia with pre/postoperative MRI findings 2).
Radiosurgery
In 386 patients treated with single-fraction radiosurgery, tumor volume was the only predictor of trigeminal neuropathy 3).
New facial numbness occurred in one patient (2.2%) with normal fifth cranial nerve function prior to stereotactic radiotherapy in 50 patients 4)
Patients receiving > 13 Gy were significantly more likely to develop trigeminal nerve neuropathy than those receiving < 13 Gy (p < 0.001) 5).
New facial numbness occurred in one patient (2.2%) with normal fifth cranial nerve function prior to stereotactic radiotherapy in 50 patients 4)
Patients receiving > 13 Gy were significantly more likely to develop trigeminal nerve neuropathy than those receiving < 13 Gy (p < 0.001) 5).
1) Betka J, Zvěřina E, Balogová Z, Profant O, Skřivan J, Kraus J, Lisý J, Syka J, Chovanec M. Complications of microsurgery of vestibular schwannoma. Biomed Res Int. 2014;2014:315952. doi: 10.1155/2014/315952. Epub 2014 May 28. PubMed PMID: 24987677; PubMed Central PMCID: PMC4058457.
2) Karkas A, Lamblin E, Meyer M, Gay E, Ternier J, Schmerber S. Trigeminal nerve deficit in large and compressive acoustic neuromas and its correlation with MRI findings. Otolaryngol Head Neck Surg. 2014 Oct;151(4):675-80. doi: 10.1177/0194599814545440. Epub 2014 Aug 1. PubMed PMID: 25085321.
3) Wowra B, Muacevic A, Fürweger C, Schichor C, Tonn JC. Therapeutic profile of single-fraction radiosurgery of vestibular schwannoma: unrelated malignancy predicts tumor control. Neuro Oncol. 2012 Jul;14(7):902-9. doi: 10.1093/neuonc/nos085. Epub 2012 May 3. PubMed PMID: 22561798; PubMed Central PMCID: PMC3379795.
4) Selch MT, Pedroso A, Lee SP, Solberg TD, Agazaryan N, Cabatan-Awang C, DeSalles AA. Stereotactic radiotherapy for the treatment of acoustic neuromas. J Neurosurg. 2004 Nov;101 Suppl 3:362-72. PubMed PMID: 15537191.
5) Sughrue ME, Yang I, Han SJ, Aranda D, Kane AJ, Amoils M, Smith ZA, Parsa AT. Non-audiofacial morbidity after Gamma Knife surgery for vestibular schwannoma. J Neurosurg. 2013 Dec;119 Suppl:E4. Review. PubMed PMID: 25077327.