title: Minimally invasive revision of a C2 isthmus screw.
abstract: OBJECTIVE
  We present a novel technique for minimally invasive revision of a cervical isthmic screw via two 18-mm transmuscular tubular accesses.
  
  
  METHODS
  A 55 year old male with combined anterior and posterior instrumentation after corpectomy of C3 to C4 complained of persistent neck pain and reduced head mobility in the follow-up examination. Isthmic screws had been placed in C2 and pedicle screws in C5. The system used is a versatile modular screw-rod system for the fixation of the occipito-cervico-thoracic spine. The patient's complaints were attributed to an inappropriately placed C2 isthmus screw. The screw was approximately 3 mm too long and perforated the C1-C2 facet joint on the left side. We replaced the screw by a shorter one through a minimally invasive transmuscular tubular approach.
  
  
  RESULTS
  The transmuscular tubular access offered an adequate exposure of the screw head. The special features of the versatile modular fixation device allowed for screw easing, removal, replacement, and tightening through the tube. The symptoms of the patient resolved completely. Intraoperative blood loss and postoperative approach-associated pain were negligible.
  
  
  CONCLUSIONS
  We conclude that in case of dorsal cervical fixation with a versatile modular screw-rod system, a minimally invasive transmuscular approach for revision of an isthmic screw may be a good alternative to open surgery.
authors.affiliation: Department of Neurosurgery, University Medical Center Freiburg, Freiburg in Breisgan, Germany.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Kogias
authors.affiliation: Department of Neurosurgery, University Medical Center Freiburg, Freiburg in Breisgan, Germany.
authors.forename: Jan-Helge
authors.initials: JH
authors.lastname: Klingler
authors.affiliation: Department of Neurosurgery, University Medical Center Freiburg, Freiburg in Breisgan, Germany.
authors.forename: Ronen
authors.initials: R
authors.lastname: Sircar
authors.affiliation: Department of Neurosurgery, University Medical Center Freiburg, Freiburg in Breisgan, Germany.
authors.forename: Martin Hermann
authors.initials: MH
authors.lastname: Deininger
authors.affiliation: Department of Neurosurgery, University Medical Center Freiburg, Freiburg in Breisgan, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hubbe
mesh_terms: D000768:Anesthesia, General; D001268:Atlanto-Axial Joint; D001863:Bone Screws; D002574:Cervical Vertebrae / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D011182:Postoperative Care; D013118:Spinal Cord Diseases / Q000601:surgery*; D055009:Spondylosis / Q000601:surgery*; D016896:Treatment Outcome