title: Fluctuations in Spinal Cord Perfusion During Adult Spinal Deformity Correction Identify Neurologic Changes: Proof of Concept.
abstract: BACKGROUND
  Adult spinal deformity (ASD) surgery carries the risk of spinal cord injury. Spinal cord ischemia is often implicated in the pathogenesis but has not been directly investigated. Here we present our index case as a proof of concept for a study evaluating the role of spinal cord perfusion (SCP) changes in ASD correction.
  
  
  METHODS
  ASD surgery was performed in the usual fashion with the addition of 1) SCP monitoring, using laser Doppler probe fixated to the dura at the level of the pedicle subtraction osteotomy (PSO) and 2) intrathecal pressure monitoring, using a lumbar drain. Somatosensory evoked potential (SSEP) and motor evoked potential (MEP) were monitored throughout the case.
  
  
  RESULTS
  An 84-year-old male with kyphoscoliosis and progressive myelopathy causing diminished motor and sensory function was treated with T4 PSO and long segment reconstruction. At baseline, SSEP signals were detectable in all 4 extremities, MEP signals were present in the right foot only, intrathecal pressure was 4 mm Hg, and mean SCP was 21.2 perfusion units. The osteotomy was performed and reduced in 2 steps. After the first step of reduction, MEP signals appeared in the left leg and increased in amplitude in the right leg, and SCP simultaneously increased to 205.6. Further reduction led to MEP signal loss in both legs and decrease in SCP to 39.2. With partial reversal of the reduction, MEP signals returned in both legs and SCP improved to 76.0. Final reduction maneuvers were then performed in a delayed fashion before closure, with stable MEP signals and a final SCP of 42.9. SSEP signals, vital signs, and intrathecal pressure were stable throughout the case. Postoperatively the patient was neurologically stable.
  
  
  CONCLUSIONS
  The present case provides the first direct evidence that fluctuations in SCP may contribute to neurologic changes during ASD surgery. Further investigation is under way to further elucidate the underlying mechanisms, with the ultimate goal of developing targeted strategies for spinal cord protection during these high-risk cases.
authors.affiliation: Barrow Neurological Institute, Division of Neurosurgery, Phoenix, Arizona, USA; Scripps Clinic, La Jolla, California, USA; San Diego Center for Spinal Disorders, La Jolla, California, USA. Electronic address: turnerjayd@gmail.com.
authors.forename: Jay D
authors.initials: JD
authors.lastname: Turner
authors.affiliation: Scripps Clinic, La Jolla, California, USA.
authors.forename: Robert K
authors.initials: RK
authors.lastname: Eastlack
authors.affiliation: Barrow Neurological Institute, Division of Neurosurgery, Phoenix, Arizona, USA.
authors.forename: Zaman
authors.initials: Z
authors.lastname: Mirzadeh
authors.affiliation: San Diego Center for Spinal Disorders, La Jolla, California, USA.
authors.forename: Stacie
authors.initials: S
authors.lastname: Nguyen
authors.affiliation: San Diego Center for Spinal Disorders, La Jolla, California, USA.
authors.forename: Jeff
authors.initials: J
authors.lastname: Pawelek
authors.affiliation: Scripps Clinic, La Jolla, California, USA; San Diego Center for Spinal Disorders, La Jolla, California, USA.
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Mundis
mesh_terms: D000369:Aged, 80 and over; D002574:Cervical Vertebrae; D018450:Disease Progression; D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring / Q000379:methods*; D007738:Kyphosis / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D017078:Laser-Doppler Flowmetry; D008297:Male; D019635:Neurosurgical Procedures / Q000379:methods*; D010027:Osteotomy; D012600:Scoliosis / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D013116:Spinal Cord / Q000098:blood supply* / Q000503:physiopathology*; D013118:Spinal Cord Diseases / Q000209:etiology; D013123:Spinal Fusion / Q000009:adverse effects; D013904:Thoracic Vertebrae; D016896:Treatment Outcome
keywords: Adult spinal deformity; Neuromonitoring; Sagittal imbalance; Scoliosis; Spinal cord perfusion; Spinal deformity surgery