title: Localization and infliction pattern of iatrogenic skull base defects following endoscopic sinus surgery at a teaching hospital.
abstract: OBJECTIVE
  Aim of this study is to evaluate the incidence, infliction patterns and management of dural injuries with cerebrospinal fluid (CSF) rhinorrhea following endoscopic sinus surgery at a teaching hospital. We present our results of over 14 years of experience from endoscopic repair of CSF rhinorrhea with long-term follow-up.
  
  
  METHODS
  A retrospective study was performed by screening 14 years of sinus surgeries for iatrogenically inflicted CSF leaks of the anterior skull base. Obtained data were analyzed to determine the infliction pattern and location of CSF leaks, surgical closure techniques and outcomes. All incidences were further evaluated with regards to the surgeons training status.
  
  
  RESULTS
  144 patients out of 6908 sinus surgeries were diagnosed with CSF rhinorrhea and underwent subsequent surgical repair. 52 patients had iatrogenic CSF leaks with 32 of the defects inflicted by the department's physician personnel. Average follow-up was 62 months, with a range of 10-168 months. The side distribution was 56.3% to the patient's right side and in 40.6% to the patient's left side. 68.7% became apparent during the initial surgery whereas 31.3% only after surgery. The most common defect location was the anterior ethmoid at the attachment of the medial concha base with 43.7%, followed by the junction between the ethmoid and sphenoid sinus with 21.9%, the frontal sinus aditus with 18.7% and the medial ethmoid region with 9.4%. With increasing training status, surgeons were more prone to cause defects at the frontal sinus aditus whereas surgeons with lesser training status caused more defects at the anterior ethmoid at the medial concha base. The posterior ethmoid and sphenoid sinus was equally prone to defects over all stages of surgical training. Initial endoscopic repair was successful in 87.5% of patients and 95% after revision surgery.
  
  
  CONCLUSIONS
  The obtained data confirm the safety of the endonasal sinus surgery according to Wigand's technique. The incidence of iatrogenic CSF leaks at a teaching hospital is not higher than at specialized rhinology departments. We observed a distinct pattern of inflicted skull base defects with different hot-spot areas, prone to damage in various stages of the surgeon's status of expertise.
authors.affiliation: Department of Otorhinolaryngology, Head & Neck Surgery, Friedrich-Alexander-University Erlangen-Nuremberg, Waldstrasse 1, D-91054 Erlangen, Germany. klaus.bumm@uk-erlangen.de
authors.forename: Klaus
authors.initials: K
authors.lastname: Bumm
authors.forename: Jennifer
authors.initials: J
authors.lastname: Heupel
authors.forename: Alessandro
authors.initials: A
authors.lastname: Bozzato
authors.forename: Heinrich
authors.initials: H
authors.lastname: Iro
authors.forename: Joachim
authors.initials: J
authors.lastname: Hornung
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002559:Cerebrospinal Fluid Rhinorrhea / Q000175:diagnosis / Q000453:epidemiology / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D002983:Clinical Competence; D003430:Cross-Sectional Studies; D004388:Dura Mater / Q000293:injuries* / Q000601:surgery; D004724:Endoscopy / Q000009:adverse effects*; D005260:Female; D006784:Hospitals, Teaching; D006801:Humans; D007049:Iatrogenic Disease; D015994:Incidence; D007223:Infant; D007396:Internship and Residency; D008297:Male; D008875:Middle Aged; D010036:Otolaryngology / Q000193:education; D011183:Postoperative Complications / Q000175:diagnosis / Q000453:epidemiology / Q000601:surgery*; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D019291:Skull Base / Q000293:injuries* / Q000601:surgery; D013536:Suture Techniques