TY - JOUR
T1 - Development of an index to characterize the "invasiveness" of spine surgery
T2 - Validation by comparison to blood loss and operative time
AU - Mirza, Sohail K.
AU - Deyo, Richard A.
AU - Heagerty, Patrick J.
AU - Konodi, Mark A.
AU - Lee, Lorri A.
AU - Turner, Judith A.
AU - Goodkin, Robert
N1 - Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2008/11/15
Y1 - 2008/11/15
N2 - STUDY DESIGN.: Prospective cohort study. OBJECTIVE.: To create and validate an index describing the extent of spine surgical intervention to allow fair comparisons of complication rates among patients treated by different surgeons, devices, or hospitals. SUMMARY OF BACKGROUND DATA.: Safety comparisons in spine surgery are limited by lack of methods that adjust for important variations in the surgical "case-mix." Among other factors, the magnitude of an operation is likely to have a substantial influence on the likelihood of complications. METHODS.: We created a spine surgery invasiveness index defined as the sum, across all vertebral levels, of 6 possible interventions on each operated vertebra: anterior decompression, anterior fusion, anterior instrumentation, posterior decompression, posterior fusion, and posterior instrumentation. We assessed the validity of this index by examining its association with blood loss and surgery duration in 1723 spine surgeries, adjusting for important factors including age, gender, body mass index, diagnosis, neurologic deficit, revision surgery, and vertebral level of surgery. RESULTS.: Blood loss increased by 11.5% and surgery duration increased by 12.8 minutes for each unit increase in the invasiveness index. The invasiveness index explained 44% of the variation in blood loss and 52% of the variation in surgery duration. For specific surgical components, blood loss increased by 9.4% and surgery duration by 11.4 minutes for each vertebral level of anterior decompression, 19.4% and 33.8 minutes for each segment of anterior instrumentation, 12.9% and 22.7 minutes for each level of posterior decompression, and 25.1% and 18.8 minutes for each segment of posterior instrumentation. CONCLUSION.: An "invasiveness" index based on the number of vertebrae decompressed, fused, or instrumented showed the expected associations with both blood loss and surgery duration. This quantitative description of surgery invasiveness may be useful to adjust for surgical variations when making safety comparisons in spine surgery.
AB - STUDY DESIGN.: Prospective cohort study. OBJECTIVE.: To create and validate an index describing the extent of spine surgical intervention to allow fair comparisons of complication rates among patients treated by different surgeons, devices, or hospitals. SUMMARY OF BACKGROUND DATA.: Safety comparisons in spine surgery are limited by lack of methods that adjust for important variations in the surgical "case-mix." Among other factors, the magnitude of an operation is likely to have a substantial influence on the likelihood of complications. METHODS.: We created a spine surgery invasiveness index defined as the sum, across all vertebral levels, of 6 possible interventions on each operated vertebra: anterior decompression, anterior fusion, anterior instrumentation, posterior decompression, posterior fusion, and posterior instrumentation. We assessed the validity of this index by examining its association with blood loss and surgery duration in 1723 spine surgeries, adjusting for important factors including age, gender, body mass index, diagnosis, neurologic deficit, revision surgery, and vertebral level of surgery. RESULTS.: Blood loss increased by 11.5% and surgery duration increased by 12.8 minutes for each unit increase in the invasiveness index. The invasiveness index explained 44% of the variation in blood loss and 52% of the variation in surgery duration. For specific surgical components, blood loss increased by 9.4% and surgery duration by 11.4 minutes for each vertebral level of anterior decompression, 19.4% and 33.8 minutes for each segment of anterior instrumentation, 12.9% and 22.7 minutes for each level of posterior decompression, and 25.1% and 18.8 minutes for each segment of posterior instrumentation. CONCLUSION.: An "invasiveness" index based on the number of vertebrae decompressed, fused, or instrumented showed the expected associations with both blood loss and surgery duration. This quantitative description of surgery invasiveness may be useful to adjust for surgical variations when making safety comparisons in spine surgery.
KW - Blood loss
KW - Casemix adjustment
KW - Invasiveness index
KW - Operative time
KW - Spinal decompression
KW - Spinal fusion
KW - Spinal instrumentation
KW - Spinal surgery case-mix
KW - Spine quality of care
KW - Surgery duration
KW - Surgery magnitude
KW - Surgical complexity
KW - Treatment intensity
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UR - http://www.scopus.com/inward/citedby.url?scp=58949103533&partnerID=8YFLogxK
U2 - 10.1097/BRS.0b013e31818dad07
DO - 10.1097/BRS.0b013e31818dad07
M3 - Article
C2 - 18981957
AN - SCOPUS:58949103533
VL - 33
SP - 2651
EP - 2661
JO - Spine
JF - Spine
SN - 0362-2436
IS - 24
ER -