title: Aberrant posterior inferior cerebellar artery injury with C1 lateral mass screw placement: a case report and review of the literature.
abstract: BACKGROUND
  Complications associated with C1 lateral mass screw placement are relatively infrequent. The most commonly feared complications include neural or vascular injury. Although both vertebral artery and internal carotid artery injuries have been discussed in the literature, there have been no reports of posterior inferior cerebellar artery (PICA) injury from C1 lateral mass screw placement. We report a case of patient who had a cerebellar stroke after C1 lateral mass screw placement, secondary to injury of an aberrant PICA.
  
  
  OBJECTIVE
  To describe the normal anatomy of the PICA, the anatomic variations previously reported in the literature, the sequela and symptoms of a patient with PICA injury, and the relevance to C1 lateral mass screw placement. No previous reports of PICA injury with a cerebellar stroke have been reported with C1 lateral mass screw instrumentation.
  
  
  METHODS
  Case report and literature review.
  
  
  METHODS
  The patient underwent an Occiput-C6 posterior instrumentation for a pathologic fracture, secondary to multiple myeloma. In the postoperative period, the patient was found to have dysarthria, imbalance, and dysdiadochokinesia. Urgent computed tomography confirmed well placed C1 lateral mass screws. Magnetic resonance imaging/Magnetic Resonance Angiography showed an infarct in the PICA distribution with an abnormal variant of the PICA coursing extracranially around C1. Neurologic monitoring did not detect the injury intraoperatively.
  
  
  RESULTS
  The patient was treated with anticoagulation and he made a reasonable recovery from his stroke.
  
  
  CONCLUSIONS
  We report the first case of an aberrant PICA injured during a C1 lateral mass screw placement, resulting in a cerebellar stroke. Consideration should be given to abnormal PICA variation when placing C1 lateral mass screws.
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA. Electronic address: nassr.ahmad@mayo.edu.
authors.forename: Ahmad N
authors.initials: AN
authors.lastname: Nassr
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA.
authors.forename: Presley P
authors.initials: PP
authors.lastname: Swann
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA.
authors.forename: John
authors.initials: J
authors.lastname: Huston
authors.affiliation: Department of Internal Medicine, Akron General Hospital, 1 Akron General Avenue, Akron OH, USA. Tel.: (330) 344-6000.
authors.forename: Mohamed M
authors.initials: MM
authors.lastname: Abdelfatah
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Rose
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA.
authors.forename: Bradford L
authors.initials: BL
authors.lastname: Currier
mesh_terms: D001863:Bone Screws / Q000009:adverse effects*; D006801:Humans; D020762:Infarction, Posterior Cerebral Artery / Q000175:diagnosis / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D020769:Posterior Cerebral Artery / Q000293:injuries*; D013123:Spinal Fusion / Q000009:adverse effects*; D020521:Stroke / Q000209:etiology*
keywords: Aberrant vascular anatomy in the cervical spine; C1 lateral mass screw placement; Complications of c1 lateral mass screw placement; Complications of cervical spine instrumentation; Posterior inferior cerebellar artery (PICA); Posterior inferior cerebellar artery injury; Stroke after c1 screw placement; Vascular injury