title: Postoperative occipital neuralgia with and without C2 nerve root transection during atlantoaxial screw fixation: a post-hoc comparative outcome study of prospectively collected data.
abstract: BACKGROUND
  Although routine transection of the C2 nerve root during atlantoaxial segmental screw fixation has been recommended by some surgeons, it remains controversial and to our knowledge no comparative studies have been performed to determine whether transection or preservation of the C2 nerve root affects patient-derived sensory outcomes.
  
  
  OBJECTIVE
  The purpose of this study is to specifically analyze patient-derived sensory outcomes over time in patients with intentional C2 nerve root transection during atlantoaxial segmental screw fixation compared with those without transection.
  
  
  METHODS
  This is a post-hoc comparative analysis of prospectively collected patient-derived outcome data.
  
  
  METHODS
  The sample consists of 24 consecutive patients who underwent intentional bilateral transection of the C2 nerve root during posterior atlantoaxial segmental screw fixation (transection group) and subsequent 41 consecutive patients without transection (preservation group).
  
  
  METHODS
  A visual analog scale (VAS) score was used for occipital neuralgia as the primary outcome measure and VAS score for neck pain, neck disability index score and Japanese Orthopedic Association score for cervical myelopathy and recovery rate, with bone union rate as the secondary outcome measure.
  
  
  METHODS
  Patient-derived outcomes including change in VAS score for occipital neuralgia over time were statistically compared between the two groups. This study was not supported by any financial sources and there is no topic-specific conflict of interest related to the authors of this study.
  
  
  RESULTS
  Seven (29%) of the 24 patients in the transection group experienced increased neuralgic pain at 1 month after surgery either because of newly developed occipital neuralgia or aggravation of preexisting occipital neuralgia. Four of the seven patients required almost daily medication even at the final follow-up (44 and 80 months). On the other hand, only four (10%) of 41 patients in the preservation group had increased neuralgic pain at 1 month after surgery, and at ≥ 1 year, no patients had increased neuralgic pain. The difference in the prevalence of increased neuralgic pain between the two groups was statistically significant at all time points (3, 6, 12, and 24 months postoperatively) except at 1 month postoperatively. The intensity of neuralgic pain, which preoperatively had not been significantly different between the two groups, was significantly higher in the transection group at the final follow-up.
  
  
  CONCLUSIONS
  C2 nerve root transection is not a benign procedure and, in our experience, more than a quarter of the patients experience increased neuralgic pain following C2 nerve root transection. Because the prevalence and intensity of postoperative neuralgia was significantly higher with C2 nerve root transection than with its preservation, we recommend against routine C2 nerve root transection when performing atlantoaxial segmental screw fixation.
authors.affiliation: Spine Center and Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Bundang Hospital, 166 Gumiro, Bundang-ku, Sungnam 463-707, Republic of Korea.
authors.forename: Jin S
authors.initials: JS
authors.lastname: Yeom
authors.forename: Jacob M
authors.initials: JM
authors.lastname: Buchowski
authors.forename: Ho-Joong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Bong-Soon
authors.initials: BS
authors.lastname: Chang
authors.forename: Choon-Ki
authors.initials: CK
authors.lastname: Lee
authors.forename: K Daniel
authors.initials: KD
authors.lastname: Riew
mesh_terms: D000328:Adult; D000368:Aged; D001268:Atlanto-Axial Joint / Q000601:surgery*; D001863:Bone Screws / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000150:complications / Q000601:surgery; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000209:etiology / Q000601:surgery; D009437:Neuralgia / Q000209:etiology*; D010147:Pain Measurement; D010149:Postoperative Pain / Q000209:etiology*; D011184:Postoperative Period; D011446:Prospective Studies; D013123:Spinal Fusion / Q000009:adverse effects* / Q000295:instrumentation; D013126:Spinal Nerve Roots / Q000601:surgery*; D016896:Treatment Outcome
keywords: Atlanto-axial screw fixation; C2 nerve root preservation; C2 nerve root transection; Occipital neuralgia, outcomes