Cranial Center of Mass Compared to C7 Plumb Line Alignment in Adult Spinal Deformity

Jamal McClendon*, Randall B. Graham, Patrick A. Sugrue, Timothy R. Smith, Sara E. Thompson, Tyler R. Koski

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Objective To report the cranial center of mass (CCOM) progression in surgically treated patients for adult spinal deformity (ASD). The C7 plumb line/sagittal vertical axis (SVA) has important relationships with patient-reported outcomes; however, this has not yet been defined for CCOM. Methods Patients with consecutive ASD who were undergoing surgery greater than 5 levels of fusion between 2007 and 2012 and had radiographic, clinical, and outcomes data spanning ≥2 years were analyzed, retrospectively. Radiographic parameters were obtained preoperatively and at 6 weeks, 1 year, and 2 years postoperatively. Statistical analysis included descriptives (measures of central tendency, dispersion, frequencies), independent Student t tests, χ2 square, Pearson correlation, and Kaplan-Meyer curve. Results Fifty-eight patients (10 male, 48 female) with a mean age of 60.5 years (range, 27-81 years) were reviewed. The mean preoperative SVA was 7.40 cm (SD = 5.51; 37/58 [63.8%] malalignment), and mean CCOM was 10.0 cm (SD = 6.58; 47/58 [81%] malalignment). Six-week postoperative SVA and CCOM was -0.17 cm (SD = 3.3) and 2.5 cm (SD = 4.11), respectively. SVA malalignment was 12.7% and CCOM malalignment was 38.2% at 6 weeks postop. Six week (absolute), 6-week change, and patient number at 6 weeks who were CCOM malaligned was significant compared with SVA (P = 0.003, P < 0.001, P < 0.001, respectively). SRS appearance worsened as preoperative SVA and CCOM increased (P < 0.05), and 2-year SRS appearance and mental health was worsened as 2-year SVA and CCOM increased (P < 0.05). SVA malalignment was 8 and 10 at 1 and 2 years, respectively, and CCOM malalignment was 24 and 32, respectively. Kaplan-Meier curve demonstrates persistent malalignment of CCOM at 6 weeks if not corrected. Conclusion CCOM alignment restoration is an important parameter in ASD, and malalignment is consistent over time.

Original languageEnglish (US)
Pages (from-to)199-204
Number of pages6
JournalWorld neurosurgery
StatePublished - Jul 1 2016


  • Adult spinal deformity
  • Cranial center of mass
  • Patient-reported outcomes
  • Sagittal vertical axis
  • Scoliosis Research Society

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology


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