title: Radiographic enhancement of the nasoseptal flap does not predict postoperative cerebrospinal fluid leaks in endoscopic skull base reconstruction.
abstract: OBJECTIVE
  Cerebrospinal fluid (CSF) leaks continue to be the most common postoperative complication in expanded endonasal skull base procedures. Currently, a multilayer closure using a vascularized nasoseptal flap is most commonly performed for large ventral skull base defects in an effort to avoid postoperative CSF leaks. We correlated nasoseptal flap enhancement with postoperative CSF leak rates in a group of skull base reconstruction patients. The nasoseptal flap enhancement was determined by immediate postoperative gadolinium-enhanced magnetic resonance imaging (MRI), which allowed for imaging of the flap's vascular pedicle. Our aim was to identify whether nasoseptal flap enhancement contributed to reduction of postoperative CSF leak rates.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  We reviewed 19 patients who underwent expanded endoscopic resections of skull base lesions of advanced complexity. We calculated the incidence of CSF leaks and measured the presence of nasoseptal flap enhancement.
  
  
  RESULTS
  Of the 19 patients with immediate postoperative MRIs, three developed postoperative CSF leaks. All three CSF leaks were in cases with enhancing vascular pedicles. In contrast, we had three patients without evidence of flap enhancement, none of whom developed a postoperative CSF leak (Fisher exact test, P = 1.0). CSF leak was associated with posterior fossa lesions (P = .25). Nasoseptal flap enhancement was associated with younger age (P = .15).
  
  
  CONCLUSIONS
  This retrospective cohort study demonstrates that although the vascularized pedicled nasoseptal flap is effective for closure of expanded endonasal skull base procedures, our experience found the actual enhancement of the flap itself does not appear to effect postoperative CSF leak rates.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA. nithin.adappa@uphs.upenn.edu
authors.forename: Nithin D
authors.initials: ND
authors.lastname: Adappa
authors.forename: Kim O
authors.initials: KO
authors.lastname: Learned
authors.forename: James N
authors.initials: JN
authors.lastname: Palmer
authors.forename: Jason G
authors.initials: JG
authors.lastname: Newman
authors.forename: John Y K
authors.initials: JY
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D065634:Cerebrospinal Fluid Leak; D002559:Cerebrospinal Fluid Rhinorrhea / Q000209:etiology / Q000601:surgery*; D002648:Child; D015331:Cohort Studies; D004724:Endoscopy / Q000009:adverse effects* / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009300:Nasal Septum / Q000601:surgery; D011183:Postoperative Complications / Q000175:diagnosis / Q000601:surgery; D011237:Predictive Value of Tests; D011856:Radiographic Image Enhancement; D019651:Plastic Surgery Procedures / Q000379:methods*; D012189:Retrospective Studies; D018570:Risk Assessment; D019291:Skull Base / Q000000981:diagnostic imaging; D019292:Skull Base Neoplasms / Q000473:pathology / Q000601:surgery*; D013524:Surgical Flaps / Q000098:blood supply* / Q000473:pathology; D016896:Treatment Outcome; D014463:Ultrasonography; D055815:Young Adult