title: Asymmetric C7 pedicle subtraction osteotomy for correction of rigid cervical coronal imbalance secondary to post-traumatic heterotopic ossification: a case report, description of a novel surgical technique, and literature review.
abstract: Deformities of the cervical spine are uncommon in the coronal plane. In this report, a unique case of a 31-year-old male with a fixed, 30° left coronal deformity due to heterotopic ossification 3 years status post poly-trauma was treated with an asymmetric C7 pedicle subtraction osteotomy (PSO).
  
  
  
  Case report.
  
  
  
  Pre-operatively, the patient had a fixed 45-degree left tilt of his neck and radiographs demonstrated a rigid 30° scoliosis, 7 cm coronal imbalance, and 4 cm negative sagittal balance, diffuse bridging bone between the spinous processes and the facet joints of C5 to T1 bilaterally. An asymmetric C7 PSO with C2-T3 posterior spinal fusion was completed without complication. There was residual 9° coronal deformity, 2.9 cm left coronal imbalance, and 2.3 cm sagittal imbalance. He had a marked improvement in his function, as assessed by the SF-36 physical component score (pre-op 31.1; post-op 44.7) and mental component score (pre-op 46.0; post-op 66.8). Post-operatively, neck disability index scores also improved (pre-op 38; post-op 16). Although the patient passed away from a drug overdose 14 months post-operatively, he did not report neck pain, he had not sought evaluation from another physician for his neck, and he had not undergone a subsequent neck operation before his passing.
  
  
  
  In this one patient, an asymmetric C7 PSO was performed safely. While it was effective in addressing a fixed cervical coronal imbalance, its efficacy and safety profile should be confirmed in larger cohorts.
authors.affiliation: Department of Orthopaedic Surgery, University of California-San Francisco (UCSF), 500 Parnassus Avenue, MU325W, San Francisco, CA, 94143-0728, USA. alekos.theologis@ucsf.edu.
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Theologis
authors.affiliation: Department of Orthopaedic Surgery, University of California-San Francisco (UCSF), 500 Parnassus Avenue, MU325W, San Francisco, CA, 94143-0728, USA.
authors.forename: Kate D
authors.initials: KD
authors.lastname: Bellevue
authors.affiliation: Department of Orthopaedic Surgery, University of California-San Francisco (UCSF), 500 Parnassus Avenue, MU325W, San Francisco, CA, 94143-0728, USA.
authors.forename: Erion
authors.initials: E
authors.lastname: Qamirani
authors.affiliation: Department of Neurological Surgery, UCSF, San Francisco, CA, USA.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Ames
authors.affiliation: Department of Orthopaedic Surgery, University of California-San Francisco (UCSF), 500 Parnassus Avenue, MU325W, San Francisco, CA, 94143-0728, USA.
authors.forename: Vedat
authors.initials: V
authors.lastname: Deviren
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D019838:Neck Injuries / Q000150:complications; D019547:Neck Pain / Q000209:etiology; D009999:Ossification, Heterotopic / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D011859:Radiography; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome
keywords: Cervical deformity; Coronal imbalance; Heterotopic ossification; Pedicle subtraction osteotomy