title: Interobserver variability of the House-Brackmann facial nerve grading system for the analysis of a randomized multi-center phase III trial.
abstract: Evidence of a high interobserver variability of the subjective House-Brackmann facial nerve grading system (HBGS) would justify cost- and time-consuming technological enhancements of objective classifications for facial nerve paresis.
  
  
  
  A total of 112 patients were recruited for a randomized multi-center trial to investigate the efficacy of prophylactic nimodipine treatment in vestibular schwannoma (VS) surgery. For the present investigation both treatment groups were pooled for the assessment of facial nerve function preoperatively, in the early postoperative course and 1 year after the surgery. Facial nerve function was documented photographically at rest and in motion and classified according to the HBGS by three independent observers (neurosurgeon, neurologist, ENT) and by the investigator of each center.
  
  
  
  Interobserver variability was considerably different with respect to the three time points depending upon the severity of facial nerve paresis. Preoperative facial nerve function was normal or only mildly impaired (HB grade I or II) and was assessed consistently in 97%. Facial nerve function deteriorated during the early postoperative course and was subsequently documented without dissent in only 36%, with one grade difference in 45%, two grade difference in 17% and three grade difference in 2%. One year after surgery, facial nerve function predominantly improved resulting in a consistent assessment in 66%. Differing ratings were observed in 34% with one grade deviation in 88% and of two grades in 12%. Patients with differing ratings of two or more grades exhibited considerably worse facial nerve function (p < 0.001).
  
  
  
  The HBGS produced comparable results between different observers in patients with normal or only mildly impaired facial nerve function. Interobserver variability increased depending on the severity of facial nerve paresis. The results suggest that the HBGS does not promote uniformity of reporting and comparison of outcomes in patients with moderate or severe facial nerve paresis.
authors.affiliation: Department of Neurosurgery, Martin Luther University of Halle-Wittenberg, Ernst-Grube-Str. 40, 06097, Halle (Saale), Germany. christian.scheller@uk-halle.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Scheller
authors.affiliation: Institute of Medical Epidemiology, Biostatistics, and Informatics, University of Halle-Wittenberg, Halle (Saale), Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Wienke
authors.affiliation: Department of Neurosurgery, University of Tübingen, Tübingen, Germany.
authors.forename: Marcos
authors.initials: M
authors.lastname: Tatagiba
authors.affiliation: Department of Neurosurgery, University of Tübingen, Tübingen, Germany.
authors.forename: Alireza
authors.initials: A
authors.lastname: Gharabaghi
authors.affiliation: Department of Neurosurgery, University of Tübingen, Tübingen, Germany.
authors.forename: Kristofer F
authors.initials: KF
authors.lastname: Ramina
authors.affiliation: Department of Oral and Maxillofacial Surgery and Facial Plastic Surgery, University of Halle-Wittenberg, Halle (Saale), Germany.
authors.forename: Konstanze
authors.initials: K
authors.lastname: Scheller
authors.affiliation: Department of Neurosurgery, Martin Luther University of Halle-Wittenberg, Ernst-Grube-Str. 40, 06097, Halle (Saale), Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Prell
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Zenk
authors.affiliation: Department of Neurosurgery, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Ganslandt
authors.affiliation: Department of Neurosurgery, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Bischoff
authors.affiliation: Department of Neurosurgery, Würzburg University Hospital, Würzburg, Germany.
authors.forename: Cordula
authors.initials: C
authors.lastname: Matthies
authors.affiliation: Department of Neurosurgery, Würzburg University Hospital, Würzburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Westermaier
authors.affiliation: Department of Neurosurgery, Bezirkskrankenhaus Günzburg, University of Ulm, Günzburg, Germany.
authors.forename: Gregor
authors.initials: G
authors.lastname: Antoniadis
authors.affiliation: Department of Neurosurgery, Bezirkskrankenhaus Günzburg, University of Ulm, Günzburg, Germany.
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Pedro
authors.affiliation: Department of Neurosurgery, University of Göttingen, Göttingen, Germany.
authors.forename: Veit
authors.initials: V
authors.lastname: Rohde
authors.affiliation: Department of Neurosurgery, University of Göttingen, Göttingen, Germany.
authors.forename: Kajetan
authors.initials: K
authors.lastname: von Eckardstein
authors.affiliation: Department of Neurosurgery, Evangelisches Krankenhaus, University of Oldenburg, Oldenburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kretschmer
authors.affiliation: Department of Neurology, University of Halle-Wittenberg, Halle (Saale), Germany.
authors.forename: Malte
authors.initials: M
authors.lastname: Kornhuber
authors.affiliation: Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA.
authors.forename: Fred G
authors.initials: FG
authors.lastname: Barker
authors.affiliation: Department of Neurosurgery, Martin Luther University of Halle-Wittenberg, Ernst-Grube-Str. 40, 06097, Halle (Saale), Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Strauss
mesh_terms: D000328:Adult; D000368:Aged; D002986:Clinical Trials as Topic / Q000592:standards*; D005154:Facial Nerve / Q000473:pathology* / Q000503:physiopathology; D005158:Facial Paralysis / Q000209:etiology / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination / Q000592:standards*; D009464:Neuroma, Acoustic / Q000601:surgery; D015588:Observer Variation; D011183:Postoperative Complications / Q000209:etiology / Q000473:pathology*; D012720:Severity of Illness Index; D055815:Young Adult
keywords: Facial nerve; House-Brackmann; Interobserver variability; Vestibular schwannoma