Recurrent spine surgery patients in hospital administrative database

Introduction: Hospital patient databases are typically used by administrative staff to estimate loss-profit ratios and to help with the allocation of hospital resources. These databases can also be very useful in following rehospitalization. This paper studies the recurrence of spine surgery patients in our hospital population based on administrative data analysis. Methods: Hospital data on 4,958 spine surgery patients operated between 2002 and 2009 were retrospectively reviewed. After sorting the cohort per ascending discharge date, the patient official name, consisting of first, middle and last names, was used as the variable determining duplicate cases in the SPSS statistical program, designating the first case in each group as primary. Yearly recurrence rate and change in procedure distribution were studied. In addition, hospital charges and length of stay were compared using the Wilcoxon-Mann-Whitney test. Results: Of 4,958 spine surgery patients 364 (7.3%) were categorized as duplicate cases by SPSS. The number of primary cases from which duplicate cases emerged was 327 meaning that some patients had more than two spine surgeries. Among primary patients (N=327) the percentage of excision of intervertebral disk procedures was 33.3% and decreased to 15.1% in recurrent admissions of the same patients (N=364). This decrease was compensated by an increase in lumbar fusion procedures. On the other hand, the rate of cervical fusion remained the same. The difference in hospital charges between primary and duplicate patients was $2,234 for diskectomy, $6,319 for anterior cervical fusion, $8,942 for lumbar fusion – lateral technique, and $12,525 for lumbar fusion – posterior technique. Recurrent patients also stayed longer in hospital, up to 0.9 day in lumbar fusion – posterior technique patients. Conclusion: Spine surgery is associated with an increasing possibility of additional spine surgery with rising invasiveness and cost.