title: Bilateral neurological deficits following unilateral minimally invasive TLIF: A review of four patients.
abstract: BACKGROUND
  Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is commonly used for the treatment of degenerative lumbar spinal disorders. The rate of postoperative neurological deficits is traditionally low. New neurological postoperative complications may be underreported. We report our infrequent rate of MI-TLIF procedures complicated by postoperative weakness.
  
  
  METHODS
  A database of 340 patients was evaluated, all of whom underwent MI-TLIF procedures performed between January 2002 and June 2012 by the senior author. We identified four cases (1.2%) whose postoperative course was complicated with bilateral lower extremity weakness. We retrospectively reviewed their past medical history, operative time, estimated blood loss, length of hospital stay, changes in intraoperative neurophysiological monitoring, and pre- and postoperative neurological exams.
  
  
  RESULTS
  The average age of the four patients was 65.5 years(range: 62-75 years), average body mass index (BMI) was 25.1 (range: 24.1-26.6), and there were three females and one male. All patients had preoperative degenerative spondylolisthesis (either grade I or grade II). All patients were placed on a Wilson frame during surgery and underwent unilateral left-sided MI-TLIF. Three out of the four patients had a past medical history significant for abdominal or pelvic surgery and one patient had factor V Leiden deficiency syndrome.
  
  
  CONCLUSIONS
  The rate of new neurological deficits following an MI-TLIF procedure is low, as documented in this study where the rate was 1.2%. Nonetheless, acknowledgement and open discussion of this serious complication is important for surgeon education. Of interest, the specific etiology or pathophysiology behind these complications remains relatively unknown (e.g. direct neural injury, traction injury, hypoperfusion, positioning complication, and others) despite there being some similarities between the patients and their perioperative courses.
authors.affiliation: Department of Neurological Surgery, Northwestern University, Chicago, IL 60661, USA.
authors.forename: Alexander T
authors.initials: AT
authors.lastname: Nixon
authors.affiliation: Department of Neurological Surgery, Northwestern University, Chicago, IL 60661, USA.
authors.forename: Zachary A
authors.initials: ZA
authors.lastname: Smith
authors.affiliation: Department of Neurological Surgery, Northwestern University, Chicago, IL 60661, USA.
authors.forename: Cort D
authors.initials: CD
authors.lastname: Lawton
authors.affiliation: Department of Neurological Surgery, Northwestern University, Chicago, IL 60661, USA.
authors.forename: Albert P
authors.initials: AP
authors.lastname: Wong
authors.affiliation: Department of Neurological Surgery, Northwestern University, Chicago, IL 60661, USA.
authors.forename: Nader S
authors.initials: NS
authors.lastname: Dahdaleh
authors.affiliation: Department of Anesthesiology, Department of Neurological Surgery, Department of Neurology, Northwestern University, Chicago, IL 60661, USA.
authors.forename: Antoun
authors.initials: A
authors.lastname: Koht
authors.affiliation: Department of Neurological Surgery, Rush University Neurosurgery, Chicago, IL 60612, USA.
authors.forename: Richard G
authors.initials: RG
authors.lastname: Fessler
keywords: Complications; lumbar; minimally invasive; spine; transforaminal lumbar interbody fusion