title: Predictive parameters for the antecedent development of hip pathology associated with long segment fusions to the pelvis for the treatment of adult spinal deformity.
abstract: BACKGROUND
  The surgical treatment of adult scoliosis frequently involves long segment fusions across the lumbosacral joints that redistribute tremendous amounts of force to the remaining mobile spinal segments as well as to the pelvis and hip joints. Whether or not these forces increase the risk of femoral bone pathology remains unknown. The aim of this study is to determine the correlation between long segment spinal fusions to the pelvis and the antecedent development of degenerative hip pathologies as well as what predictive patient characteristics, if any, correlate with their development.
  
  
  METHODS
  A retrospective chart review of all long segment fusions to the pelvis for adult degenerative deformity operated on by the senior author at the Duke Spine Center from February 2008 to March 2014 was undertaken. Enrolment criteria included all available demographic, surgical, and clinical outcome data as well as pre and postoperative hip pathology assessment. All patients had prospectively collected outcome measures and a minimum 2-year follow-up. Multivariable logistic regression analysis was performed comparing the incidence of preoperative hip pain and antecedent postoperative hip pain as a function of age, gender, body mass index (BMI), and number of spinal levels fused.
  
  
  RESULTS
  In total, 194 patients were enrolled in this study. Of those, 116 patients (60%) reported no hip pain prior to surgery. Eighty-three patients (71.6%) remained hip pain free, whereas 33 patients (28.5%) developed new postoperative hip pain. Age, gender, and BMI were not significant among those who went on to develop hip pain postoperatively (P< 0.0651, 0.3491, and 0.1021, respectively). Of the 78 patients with preoperative hip pain, 20 patients (25.6%) continued to have hip pain postoperatively, whereas 58 patients reported improvement in the hip pain after long segment fusion for correction of their deformity, a 74.4% rate of reduction. Age, gender, and BMI were not significant among those who continued to have hip pain postoperatively (P< 0.4386, 0.4637, and 0.2545, respectively). Number of levels fused was not a significant factor in the development of hip pain in either patient population; patients without preoperative pain who developed pain postoperatively (P< 0.1407) as well as patients with preoperative pain who continued to have pain postoperatively (P< 0.0772).
  
  
  CONCLUSIONS
  This study demonstrates that long segment lumbosacral fusions are not associated with an increase in postoperative hip pathology. Age, gender, BMI, and levels fused do not correlate with the development of postoperative hip pain. The restoration of spinal alignment with long segment fusions may actually decrease the risk of developing femoral bone pathology and have a protective effect on the hip.
authors.affiliation: Department of Neurological Surgery, Montefiore Medical Center/Albert Einstein School of Medicine, Bronx, New York, USA.
authors.forename: Merritt D
authors.initials: MD
authors.lastname: Kinon
authors.affiliation: Department of Neurological Surgery, Montefiore Medical Center/Albert Einstein School of Medicine, Bronx, New York, USA.
authors.forename: Rani
authors.initials: R
authors.lastname: Nasser
authors.affiliation: Department of Neurological Surgery, Montefiore Medical Center/Albert Einstein School of Medicine, Bronx, New York, USA.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Nakhla
authors.affiliation: Department of Neurological Surgery, Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Owoicho
authors.initials: O
authors.lastname: Adogwa
authors.affiliation: Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Jessica R
authors.initials: JR
authors.lastname: Moreno
authors.affiliation: Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Harowicz
authors.affiliation: Department of Neurosurgery, Baylor College of Medicine Medical Center, Houston, Texas, USA.
authors.forename: Terence
authors.initials: T
authors.lastname: Verla
authors.affiliation: Department of Neurological Surgery, Montefiore Medical Center/Albert Einstein School of Medicine, Bronx, New York, USA.
authors.forename: Reza
authors.initials: R
authors.lastname: Yassari
authors.affiliation: Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Bagley
keywords: Adult spine deformity; degenerative spine disease; hip pain; long segment fusion; lumbar spondylosis; pelvis; sacrum; sagittal balance; spinal alignment; spine fusion