• INTRODUCTION
    • Spondylolysis is an increasingly common diagnoses for young individuals and presents with a wide range of pathological and clinical findings. Most patients are treated conservatively, and surgery is reserved for severe cases. This is a populations study defining the incidence of spondylolysis in the Kids' Inpatient Database (KID) and assess trends in diagnoses, causes, and treatments.
  • METHODS
    • Retrospective analysis of the prospectively collected information in KID was performed for the years 2003 through 2012. Patients with a diagnosis of spondylolysis (ICD-9-CM 756.11) between the ages of 0 and 20 years in the KID were identified. Incidence of spondylolysis was established using KID-supplied hospital- and year-adjusted trend weights. Demographics including age, race, gender, and Charlson Comorbidity Index were assessed for all spondylolysis patients. Primary outcome measures were yearadjusted and hospital-adjusted incidence of spondylolysis. Secondary outcome measures were concurrent diagnoses and surgical details.
  • RESULTS
    • Six hundred and sixteen patients with a diagnosis of spondylolysis (329 with primary diagnosis) were identified (female: 53.8%; age: 15.27 ± 3.32 years). The incidence of spondylolysis is 7 per 100,000 patients nationally. Spondylolysis incidence has increased over time (p < 0.001) though the operative rate for spondylolysis has remained the same in the last decade (70% average, p = 0.52). The average CCI is 0.234, the average length of stay is 3.76 days and 92.4% of patients were discharged home. The etiology of the spondylolysis was trauma in 8.6% of patients (3.2% car crash, 1.9% pedestrian, 1.3% fall, 1.3% assault, 1.1% other transport, 1.0% sports, 0.3% motorcycle, 0.2% firearm, 0.2% bicycle; 1.9% reported multiple trauma etiologies). The most common concurrent diagnoses for all spondylolysis patients were spondylolisthesis (28%), idiopathic scoliosis (4.4%), cerebral palsy (1.9%), and spina bifida (1.8%). Four hundred and thirty patients with spondylolysis underwent surgical treatment and 40% of the surgically treated patients had spondylolisthesis. The rate of fusions was 54.9% fusions and 21% decompression, though the rate of fusions or decompressions being performed for spondylolysis has remained the same in the last decade (average fusion rate: 55%; average decompression rate: 18%; both p > 0.05). Levels fused and complications did not differ depending on whether or not decompression was performed (p > 0.05). The posterior-only approach was used in 62.2% of surgeries and were mostly 2 to 3 level procedures (63.5%). Perioperative complications occurred in 8.1% of patients, with the most common complications being device-related (2.3%), respiratory (1.5%), and digestive (1.5%).
  • CONCLUSIONS
    • The national incidence of spondylolysis has increased over time, and the surgical rate and treatment techniques have remained constant. The most common concurrent diagnoses were idiopathic scoliosis, cerebral palsy, and spina bifida. Further work is required to determine the significance of these trends and associations.