2016 OPAM Mid-Year Educational Conference, sponsored by AOCOPM Thursday, March 10, 2016 C-1

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1 Long-term Outcomes of Lumbar Fusion Among Workers Compensation Subjects : An Historical Cohort Study Trang Nguyen M.D., Ph.D. David C. Randolph M.D, M.P.H. James Talmage MD Paul Succop PhD Russell Travis MD Spine.2011 Feb 15;36(4): Background Lumbar arthrodesis is a surgical procedure performed to join adjacent spinal vertebrae utilizing bone grafts and/or instrumentation to eliminate mobility. Developed in 1911 Original indications: Spinal instability Tuberculosis Tumors Trauma Scoliosis 1 2 Posterior Lumbar Fusion Anterior Lumbar Fusion 3 4 Failed Fusion Lumbar Fusion Volumes by Diagnoses 5 6 C-1

2 Lumbar Fusion by Age & Diagnoses Overview of study design Historical Cohort 725 lumbar fusion cases, 725 computer randomized non-surgical controls The primary outcome was return to work status. The secondary outcomes were permanent disability status, complications, re-operations, and opiate utilization. Ohio Workers Compensation Database 7 8 Population/Eligibility ICD-9 CM Diagnoses for Low Back Pain Subjects years of age with chronic low back pain (CLBP) classified by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9 CM) diagnoses. Current- Procedural-Terminology (CPT) codes for lumbar fusion Controls are randomized and controlled for age, gender, and diagnoses. Subjects with spinal fracture, involvement of other body parts, cervical and/or thoracic areas, head trauma, or pregnancy were excluded Spondylolisthesis- acquired/ degenerative Radiculitis (leg or lumbar or lumbosacral) Lumbago or sciatica due to displacement of Intervertebral disc OR Neuritis or radiculitis due to displacement or rupture of lumbar Intervertebral disc Lumbar stenosis Spondylosis lumbar or lumbosacral without myelopathy Degenerative Intervertebral disc lumbosacral Sciatica Displacement of lumbar Intervertebral disc without myelopathy Discogenic syndrome NOS or Disc Herniation or Intervertebral disc NOS (extrusion, prolapse, protrusion, rupture) 9 10 CPT Codes for Lumbar Fusion CPT Codes for Lumbar Fusion 1. Posterior un-instrumented fusion a. 1 level b. Multi-level and Posterior fusion with instrumentation a. 1 level and 22840; b. Multi-level and and PLIF posterior lumbar interbody fusion a. 1 level and and b. Multi-level and and and ALIF- anterior lumbar interbody fusion a. 1 level and b. Multi-level and and Anterior and Posterior fusion 360 a.1 level and and and b. Multi-level and and and and and C-2

3 Definitions of Measured Outcomes Return to work status: Considered successful if the injured worker returned to employment two years after the date of surgery for cases or 2 years post injury for controls as part-time, full-time workers with the same or a different employer. Unsuccessful RTW was defined as failure to RTW in any capacity. Disability status: workers who were awarded permanent total disability (PTD) status post surgery or post injury. PTD is permanent lifetime compensation and the injured worker will never work again in any capacity. 13 Definitions of Measured Outcomes Complications: (ICD-9 codes) Early major systemic post surgical complications: death, meningitis, myocardial infarction, cardiac arrhythmia, pneumonia, pulmonary embolism, acute renal failure, pancreatitis, acute prostatitis, urinary tract infection, gastrointestinal bleed, and avascular necrosis of the femoral head. Implant complications: failed and/or implant malposition. Late spinal complications: disc space infection, pseudarthrosis, post-laminectomy syndrome, adjacent disc degeneration, stenosis, spondylolisthesis, and adjacent vertebral fracture. Neurologic complications: impotence, incontinence and reflex sympathetic dystrophy. Wound complications: minor wound infection and incisional hernia Mortality status peri-operative mortality (i.e. within 6 weeks post-op) and long term mortality from any cause. 14 Definitions of Measured Outcomes Definitions of Measured Outcomes Re-operation: (CPT codes) Repeat lumbar surgical procedure(s) performed during the follow up period. These repeat surgical procedures included: fusions, removal and/or insertion of fixation device(s), laminectomy, bone grafts, exploration, and decompression of the lumbar spine. 15 Opioids The number of different narcotic analgesic prescriptions filled and the duration of usage are collected for all subjects. Medication names are standardized using national drug codes descriptions. For each medication, the date, name, dose, and quantity dispensed was collected from the bill line item detail care database. Dosages are calculated in daily total morphine equivalents for the duration of the study. Only oral preparations are included. 16 Specific risk factors are collected 13,656 Workers with low back pain with injury dates 01/01/99-12/31/2001 Age at injury Litigation status Height and weight Smoking status (current smokers, ex-smokers, never smokers) Gender Pre-operative diagnoses Types of surgical approach Time from injury to surgery Amount of time off work prior to surgery Number of lumbar vertebrae involved in the operation Rehabilitation history Vocational training after surgery or injury Education Wages Lumbar MRI findings Discograms Previous Surgical history Marital Status 3,138 Subjects with lumbar fusion 2,413 Subjects excluded: 1,001 Subjects had lumbar fusion after the cut off date of 7/31/03 1,412 Subjects had injuries to other body parts in addition to the lumbar spine 725 Final surgical cases 10,518 Non-surgical controls 6,446 Controls with matching age, gender, & ICD-9 diagnoses to 725 cases 2,859 Controls excluded due to injuries of other body parts in addition to the lumbar spine 3,587 Eligible controls 725 Randomized controls C-3

4 3,138 Injured Workers with Lumbar Fusion with Injury dates 01/01/99-12/31/2001 2,413 Excluded: 1,001 had lumbar fusion after the cut off date of 7/31/03 and 1,412 have injuries to other body parts in addition to the lumbar spine Results: Baseline Characteristics of Lumbar Fusion Cases and Non-surgical Controls Characteristic Cases Non-surgical controls P Value No. of subjects Age a (years) (mean + SD) Sex No. (%) Male 524 (72.28%) 570 (78.62%).005 Female 201 (27.72%) 155 (21.38%) BMI b (mean + SD) Education- No. (%) Didnot complete high school 162 (28.37%) 51 (29.31%) 725 Final Surgical Subjects Complete high school 299 (52.36%) 88 (50.57%).35 Didnot complete college 88 (15.41%) 23 (13.22%) Completionof college or higher 22 (3.85%) 12 (6.90%) 78 ALIF One Level 34 ALIF Multi-Level 26 Post Uninstr. One Level 5 Post Uninstr. Multi Level Legal representation -No. (%) Yes 665 (91.72%) 544 (75.03%) <.001 No 60 (8.28%) 181 (24.97%) Marital status- No. (%) 30 AP 360 One Level 39 AP 360 Multi-Level 310 PLIF One Level 68 PLIF Multi-Level 47 Post w/ Instr. One Level 88 Post w/ Instr. Multi Level Divorced 108 (14.90%) 103 (14.49%) Married 446 (61.52%) 429 (60.34%) Single 164 (22.62%) 176 (24.75%) Widowed 7 (0.97%) 3 (0.42%) 20 Results: Baseline Characteristics of Lumbar Fusion Cases and Non-surgical Controls Characteristic Cases Non-surgical controls P Value Smoking history- No. (%) Current smoker 404 (58.98%) 174 (53.54%) Ex-smoker 68 (9.93%) 23 (7.08%).02 Never smoker 213 (31.09%) 128 (39.38%) Weekly Wages (Mean + SD) <.001 Diagnoses c - No. (%) Disc Degeneration 292 (24.25%) 221 (22.10%) Disc Herniation 580 (48.17%) 515 (51.50%) Radiculopathy 142 (11.79%) 179 (17.90%) <.001 Spondylolisthesis 113 (9.39%) 29 (2.90%) Spinal Stenosis 77 (6.40%) 56 (5.60%) Discography- No. (%) No 490 (67.59%) 675 (93.10%) <.001 Yes 235 (32.41%) 50 (6.90%) Lumbar MRI Number of levels with decreased or loss of signal intensity No. (%) Zero level 8 (1.10%) 30 (4.78%) One level 357 (49.31%) 204 (32.54%) Two levels 230 (31.77%) 239 (38.12%) <.001 Three or more levels 129 (17.82%) 154 (24.56%) 21 Results: Return to Work, Rehabilitation and Disabled Status RTW no RTW Cases 188(25.93%) 367(50.62%) Controls 483(66.62%) 163(22.48%) Rehab Cases 64(8.83%) Controls 43(5.93%) PTD Cases 82 (11.31%) Controls 11 (1.52%) 7 cases and 14 controls with no RTW status Loss to follow up = 1.45% 22 Results: Duration of Time Off Cases Controls P Value Total number <.001 of days off Number of days from DOI to DOS Number of days off work from DOI to DOS Results: Re-operations 194 cases have re-operations (26.76%) Re-operations no.(%) Once 158/194 (81.44%) Twice 28/194 (14.43%) > Three 08/194 (4.12%) No re-operation 531/725 (73.24%) C-4

5 Results: Re-operations Re-operations no.(%) At <1 yr 83(34.44%) At < 2yr 77(31.95%) At < 3 yr 45(18.67%) At < 4 yr 15(06.22%) At < 5 yr 15(06.22%) At < 6 yr 06(02.49%) Results: Complications Category no.(%) 264 cases (36.4%) Early major systemic 45(6.21%) Implant complications 34(4.69%) Late spinal complications 183(25.24%) Neurologic complications 18(2.48%) Wound complications 27(3.72%) No complications 461(63.59%) Results: Mortality Post op (no.-%) <6 weeks 0/725 (0%) <3months 1/725 (0%) >3 months 16/725(2.2%) Controls Mortality 11(1.52%) P value:.26 Results: Daily amount of Morphine Average daily MEQ (Mean + SD) Cases Controls P Value <.001 Number of subjects taking opioids 614 (84.69%) 354 (48.83%) <.001 Average daily MEQ before surgery Average daily MEQ after surgery Maximum daily MEQ (controls) Before surgery After surgery Results: Univariate Logistic Regression of Return to Work Status Surgical Unadjusted P Non-Surgical Unadjusted P OR (95% CI) Value OR (95% CI) Value Independent Variables Age a (years) 1.00 ( ) ( ).60 BMI b 0.99 ( ) ( ).83 Complications c <.001 No complications (Reference) Early Major Systemic 0.22 ( ).005 Implant 0.07 ( ).01 Late Spinal 0.49 ( ).002 Neurologic 0.42 ( ).29 Wound Complications 1.27 ( ).68 Total days off d 0.93 ( ) < ( ) <.001 Days off prior to surgery e 0.93 ( ) <.001 Days from injury to surgery f 0.98 ( ).03 Diagnosis g Degenerative disc disease (Reference) Herniated disc 0.81 ( ) ( ).14 Radiculopathy 2.00 ( ) ( ).03 Spondylolisthesis 0.80 ( ) ( ).94 Spinal stenosis 1.75 ( ) ( ) Results: Univariate Logistic Regression of Return to Work Status Surgical Unadjusted P Non-Surgical P OR (95% CI) Value Unadjusted OR (95% CI) Value Independent Variables Discogram (yes) h 0.65 ( ) ( ) <.001 Education Did not complete high school (Reference) Completed high school 1.99 ( ) ( ).40 Did not complete college 1.44 ( ) ( ).03 Completed college or graduate 3.13 ( ) ( ).14 education Fusion Type.72 Posterior Un-instrumented single level fusion (Reference) ALIF multi-level i 1.41 ( ).60 ALIF single level 0.78 ( ).67 Anterior-posterior 360 multi-level 0.35 ( ).16 Anterior-posterior 360 single level 0.92 ( ).90 PLIF multi-level j 1.24 ( ).71 PLIF single level 0.92 ( ).88 Posterior un-instrumented multi-level 0.92 ( ).95 Posterior with instrumentation multi-level 1.12 ( ).84 Posterior with instrumentation single level 0.92 ( ) C-5

6 Results: Univariate Logistic Regression of Return to Work Status Surgical Unadjusted P Non-Surgical P OR (95% CI) Value Unadjusted OR (95% CI) Value Independent Variables Gender 0.90 ( ) ( ).21 Male (Reference) Legal representation 3.98 ( ) < ( ) <.001 Having legal representation (Reference) Marital status Single (Reference) Divorced 1.26 ( ) ( ).85 Married 1.37 ( ) ( ).05 Widowed 0.61 ( ) ( ).21 Morphine(daily) k 0.71 ( ) < ( ).65 Smoking <0.001 Never smoker (Reference) Results: Univariate Logistic Regression of Return to Work Status Surgical Unadjusted P Non-Surgical P OR (95% CI) Value Unadjusted OR (95% CI) Value Independent Variables Lumbar MRI Zero level (Reference) Total MRI level l One level 0.93 ( ) ( ).95 Two levels 0.93 ( ) ( ).60 Three levels 1.89 ( ) ( ).61 Four levels 0.67 ( ) ( ).63 Five levels 0.86 ( ) ( ).94 Total rehabilitation sessions m 0.92 ( ) < ( ) <.001 Total vocational sessions n 1.10 ( ) ( ).12 Weekly wages o 1.13 ( ) < ( ) <.001 Current smoker 0.53 ( ) ( ) <.001 Ex-smoker 0.70 ( ) ( ).09 Re-operations <.001 No re-operation (Reference) Once 0.28 ( ) <.001 Twice 0.32 ( ) Multivariate Logistic Regression All subjects Cases Controls Patient Characteristic (95% CI) P Value (95%CI) P Value (95%CI) P Value Current smoker ( ) Total days off a 0.93 ( ) Weekly Wages b 1.09 ( ) < <.001 ( ) ( ) Complications c.007 No complications (Reference) Early Major Systemic ( ) Implant ( ) Late Spinal ( ) Neurologic ( ) Wound Complications ( ) ( ) Multivariate Logistic Regression Patient Characteristic All subjects (95% CI) P Value Cases (95%CI) Days off work prior to surgery d 0.94 ( ) Legal representation 3.43 ( ) Morphine(daily) e 0.83 ( ) Re-operation 0.42 ( ) P Value < <.001 Controls (95%CI) P Value Abbreviations: CI, confidence interval; OR, odds ratio. a Total number of days off work from the date of injury to the end of the study. Odds ratio for return to work status at 30 daysoff. b Weekly wages are reported as an increase of dollars. Odds ratio for return to work status with an increase of at $ per week. c Post surgical complications for cases only. d Number of days off work from date of injury to date of surgery. Odds ratio for return to work status at 30 daysoff work prior to surgery. e Daily morphine dose expressed as total morphine equivalent units (MEQ). Odds ratio for return to work status at a dose of 25 total morphine equivalent units per day. 34 Total Days off as Predictor of RTW status Days off as Predictor of RTW status 30 days off Cases OR of RTW 0.93, p<.001 Controls OR of RTW 0.85, p< C-6

7 Weekly Wages as Predictor of RTW status Weekly Wages as Predictor of RTW status Increase of $ US dollars/ per week Cases OR of RTW 1.12, p<.008 Controls OR of RTW 1.16, p< Daily Morphine Equivalents as Predictor of RTW status Daily Morphine Equivalents as Predictor of RTW status Cases OR of RTW at 100 MEQ units 0.25, p<.001 Controls OR of RTW at 100 MEQ units 0.93, p< Conclusions Most common diagnoses disc degeneration and herniation Most common approach posterior single level with instrumentation Fusion cases more likely to be disabled (n= 82 vs. n=11, p=.001) Less likely to RTW (n= 367 vs. n=163, p=<.001) Failure to RTW status is consistent with Washington s state data (64% vs. 62%) High complication rate (adjacent segment degeneration and failed back syndrome) Consistent with Washington s state data (15% vs. 12%) Re-operation rate of 27% vs. 22% and 20% Morphine dose increase post surgery for cases Conclusions Controls OR of RTW at 30 days off work 0.85 vs. OR of 0.93 for cases Wages C-7

8 Study limitations and strengths Limitations Not all risk factors are documented consistently Other IVs that can affect outcomes are not collected? Unable to randomize the exposure (treatments) Strengths Prolonged follow up time Very large cohort Objective outcomes were measured Data include all providers in Ohio 43 Authors The authors have no financial and no conflict of interest relating to this study. 44 C-8

Osteoarthrosis, unspecified whether generalized or localized, lower leg. Osteoarthrosis, localized, not specified whether primary or secondary, pelvic

Osteoarthrosis, unspecified whether generalized or localized, lower leg. Osteoarthrosis, localized, not specified whether primary or secondary, pelvic Page 1 Appendix TABLE E-1 Codes (and Definitions) in Humana Database Used for Study Inclusion and Exclusion of Patients Who Underwent,, or 1 to 2-Level Inclusion ICD-9-P-8154 Total knee replacement ICD-9-D-71596