1 Appendix
Subject selection
Figure 1 includes the ICD-9 and CPT codes used to characterize each subject’s lumbar
comorbidities, the type of fusion each subject underwent, and the ICD-9 codes used to identify depression.
Permanent disability data was provided directly by the Ohio BWC. We excluded subjects who received either total or partial permanent disability benefits.
We excluded subjects with a positive smoking history using the ICD-9 codes V15.82
(history of tobacco use), 305.1-305.13 (tobacco abuse), and 649.00-649.04 (tobacco use), and/or if subjects utilized prescription smoking deterrents within the drug classes codes H7N, J3A, J3C.
Failed back surgery syndrome was identified with the ICD-9 code 722.83.
We used CPT codes in the ranges of 63005-63048 and/or 62297-62303 to exclude subjects who underwent a decompression procedure before index fusion.
Secondary outcome measures
For prescription opioid analgesia, we used the specific opioid prescription
(hydroxymorphone, oxycodone, etc.) and converted them to morphine equivalents (MEQs). Also, we knew the quantity of pills in each prescription, the number of days these pills would cover if taken as directed by their physician, and the associated dates each prescription was filled on. From this information, we were able to calculate the
Appendix
2 specific variables used to characterize each subject’s opioid analgesic utilization in this study.
For new psychological comorbidity, we determined which subjects had ICD-9 codes for
such conditions within 3 years after fusion that were not diagnosed before fusion. Table 1 includes the codes we used for depression. For anxiety, we used 300.00-300.09 (anxiety states) and 293.84 (anxiety disorder in conditions classified elsewhere). For adjustment reaction disorders, we used 309.0-309.9 (adjustment reaction). For PTSD, we used 309.81 (posttraumatic stress disorder), for bipolar disorder, we used 296.5-296.89 (bipolar mood disorders), and for schizophrenia, we used 295.00-295.95 (schizophrenic disorders).
To quantify the number of psychotherapy sessions each subject utilized, we used CPT
codes in the range of 90804 through 90876 and their associated dates of service. Each time a CPT code was in a claim on a unique date of service, we counted that as one psychotherapy session. Psychological diagnostic exams were identified using CPT codes in the range of 90791-90830.
For rates of postsurgical infection, we used ICD-9 codes 998.59 (other postop infection) and 998.51 (infected postop seroma) and their associated date of diagnosis.
Pseudoarthrosis was identified with the ICD-9 code 733.82 (nonunion of fracture). A
specific ICD-9 code for failed fusion does not exist. Instead, the ICD-9 code for nonunion can be used.
Mortality and medical cost data was directly provided by the Ohio BWC.
