title: Ultrasonographic quantification of spinal cord and dural pulsations during cervical laminoplasty in patients with compressive myelopathy.
abstract: OBJECTIVE
  Pulsatile movements of the dura mater have been interpreted as a sign that the cord is free within the subarachnoid space, with no extrinsic compression. However, the association between restoration of pulsation and adequate decompression of the spinal cord has not been established. The present study investigated the relationship between the extent of spinal cord decompression and spinal cord and dural pulsations based on quantitative analysis of intraoperative ultrasonography (US).
  
  
  METHODS
  Eighty-five consecutive patients (55 males, 30 females; mean age, 64 ± 13 years) who underwent cervical double-door laminoplasty to relieve compressive myelopathy were enrolled. Spinal cord decompression status was classified as: Type 1 (non-contact), the subarachnoid space was retained on the ventral side of the cord, Type 2 (contact and apart), the cord showed both contact with and separation from the anterior element of the cervical spine, or Type 3 (contact), the cord showed continuous contact with the anterior element of the cervical spine. Spinal cord and dura mater dynamics were quantitatively analyzed using automatic video-tracking software. Furthermore, the intensity of spinal and dural pulsation was compared with the recovery of motor function at 1 year after surgery as measured by increase in the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ).
  
  
  RESULTS
  Spinal cord pulsation amplitude ranged from 0.01 to 0.84 mm (mean 0.30 ± 0.16 mm) and dural pulsation amplitude ranged from 0.01 to 0.38 mm (mean 0.14 ± 0.08 mm). Average spinal cord pulsation amplitude in Type 2 patients was significantly larger than that in the other groups, whereas, average dural pulsation amplitudes were similar for all three groups. There was a significant correlation between spinal cord and dural pulsation amplitudes in Type 1 patients, but not in Type 2 or Type 3 patients. Type 3 patients showed a particularly poor correlation between spinal cord and dural pulsations. Spinal cord pulsation amplitude was moderately correlated with the recovery of motor function evaluated by JOACMEQ.
  
  
  CONCLUSIONS
  The present results suggest that restoration of dural pulsation is not an adequate indicator of sufficient decompression of the spinal cord following a surgical procedure.
authors: Department of Orthopaedics, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan.
authors: Atsushi
authors: A
authors: Kimura
authors: Atsushi
authors: A
authors: Seichi
authors: Hirokazu
authors: H
authors: Inoue
authors: Teruaki
authors: T
authors: Endo
authors: Michiyoshi
authors: M
authors: Sato
authors: Takahiro
authors: T
authors: Higashi
authors: Yuichi
authors: Y
authors: Hoshino
mesh_terms: D000368:Aged; D019299:Decompression, Surgical; D004388:Dura Mater / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007796:Laminectomy; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D020127:Recovery of Function; D013116:Spinal Cord / Q000000981:diagnostic imaging*; D013117:Spinal Cord Compression / Q000000981:diagnostic imaging* / Q000601:surgery; D014463:Ultrasonography