title: K-Wire fracture during minimally invasive transforaminal lumbar interbody fusion: Report of six cases and recommendations for avoidance and management.
abstract: BACKGROUND
  Although rare, minimally invasive spine techniques do have the risk of intraoperative device failure. Kirschner wire (K-wire) fractures during minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) have not been previously reported. This report focuses on the incidence of k-wire fractures following MI-TLIF and describes techniques to help avoid and treat these fractures when they occur.
  
  
  METHODS
  
  
  
  METHODS
  (i) patients underwent 1, 2, or 3 level MI-TLIF over a 10-year period and (ii) had a k-wire fracture leading to a retained fragment. Exclusion criteria included: >10° coronal curves, significant sagittal malalignment, infection, and preoperative instrumentation failure.
  
  
  RESULTS
  Of 513 patients undergoing MI-TLIF, 6 (1.2%) sustained k-wire fracture (3 males, 3 females, mean age 43 ± 13 years). Complications included k-wire fracture alone (4 patients), cerebrospinal fluid (CSF) leak (1 patient), and both ileus and revision for hardware removal (1 patient). All six patients went home postoperatively. The mean follow-up duration was 27.7 ± 37.4 months. All retained k-wire fragments were located in the vertebral bodies at the tip of the pedicle screws; none breached the anterior cortex of the vertebral bodies. None of the k-wires migrated at final follow-up 7.8 years (93.7 months) postoperatively. Furthermore, no complications were attributed to retained k-wires.
  
  
  CONCLUSIONS
  K-wire fractures during MI-TLIF are rare (incidence of 1.2%) and retained k-wire segments led to no postoperative complications (e.g. no migration).
authors.affiliation: Department of Neurological Surgery, Northwestern University, Feinberg School of Medicine, 676 N. St. Clair Street, Suite 2210, USA.
authors.forename: Justin K
authors.initials: JK
authors.lastname: Scheer
authors.affiliation: Department of Neurological Surgery, Northwestern University, Feinberg School of Medicine, 676 N. St. Clair Street, Suite 2210, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Harvey
authors.affiliation: Department of Neurological Surgery, Northwestern University, Feinberg School of Medicine, 676 N. St. Clair Street, Suite 2210, USA.
authors.forename: Nader S
authors.initials: NS
authors.lastname: Dahdaleh
authors.affiliation: Department of Neurological Surgery, Northwestern University, Feinberg School of Medicine, 676 N. St. Clair Street, Suite 2210, USA.
authors.forename: Zachary A
authors.initials: ZA
authors.lastname: Smith
authors.affiliation: Department of Neurological Surgery, Rush University School of Medicine, Chicago, IL, 60611, USA.
authors.forename: Richard G
authors.initials: RG
authors.lastname: Fessler
keywords: Complications; K-wire; Kirschner wire; TLIF; minimally invasive; transforaminal lumbar interbody fusion