Spine Surgery. Center for the Evaluative Clinical Sciences. Table of Contents

Transcription

1 Spine Surgery A Report by the Dartmouth Atlas of Health Care CMS FDA Collaborative The Dartmouth Atlas Project provides ongoing population-based monitoring of the rates of use of medical and surgical services in the fee-for-service Medicare population. This report focuses on trends and regional variations in spine surgery. Table of Contents National Trends in Utilization and Spending for Spine Surgery 3 Regional Variation in Rates of Spine Surgery 5 Total Spine Surgery 5 Lumbar Discectomy and Laminectomy 6 Lumbar Fusion 7 Non-Lumbar Discectomy and Laminectomy 8 Non-Lumbar Fusion 9 Lumbar Discectomy and Laminectomy in Billings, Montana 14 Lumbar Fusion in Sarasota, Florida 15 Methods 16 Appendix Table 17 Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery

2 Spine Surgery Since the publication of the first edition of the Dartmouth Atlas of Health Care in 1996, information about population-based, age-, sex-, and race-adjusted rates of particular surgical procedures among U.S. hospital referral regions (HRRs) has been available to the public. Hospital referral regions represent regional health care markets for tertiary medical care. Each HRR contains at least one hospital that performs major cardiovascular procedures and neurosurgery. More information on how hospital referral regions were defined is available in the Methods section of this document, and in the Appendix on the Geography of Health Care, located on our web site. Numerous technological advances in spine surgery have been made over the past 10 to 20 years. Although there has been a trend toward greater use of technology in spine surgery, evidence of a substantial clinical benefit from this technology remains limited. In rates of lumbar spine (low back) surgery began to increase, with rates of fusion increasing faster than non-fusion surgery. These rates were coincident with the FDA approval of a new fusion device. Much of the increase has been seen in those age 60 and older. However, rates of fusion are also increasing for those under Rates of non-lumbar spine surgery are also increasing. In the cervical spine (neck), fusion procedures are increasing proportionately more than non-fusion surgery. 1. Deyo, RA, Gray, DT, Kreuter W, Mirza S, Martin BI. United States Trends in Lumbar Fusion Surgery for Degenerative Conditions. Spine. 30(12): , June 15, Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery

3 National Trends in Utilization and Spending for Spine Surgery Overall rates of spine surgery increased steadily during the decade The national average rate of spine surgery rose from 2.5 procedures per 1,000 Medicare enrollees in 1992 to 4.0 per 1,000 in 2003, an increase of 63% (Figure 1A). Rates of discectomy and laminectomy for the treatment of lumbar (low back) pain rose and then fell during the same period (Figure 1B). In 1992, the U.S. average rate of lumbar discectomy and laminectomy was 1.7 per 1,000. The rate peaked at 2.2 per 1,000 enrollees in 2001, and then decreased to 2.1 per 1,000 in By contrast, rates of lumbar fusion rose steadily. In 1992, the U.S. average rate of lumbar fusion was 0.3 per 1,000. The rate increased over the following decade, doubling to 0.6 per 1,000 enrollees in 1998, and reaching 1.1 per 1,000 in Non-lumbar spine procedures showed similar patterns; discectomy and laminectomy rates remained essentially level, while fusion rates more than doubled, from 0.2 per 1,000 Medicare enrollees in 1992 to 0.5 in U.S. average rate of spine surgery per 1,000 U.S. average rate of discharges per 1, Figure 1A. Trends in Overall Rates of Spine Surgery, laminectomy Lumbar fusion Non-lumbar fusion Non-lumbar discectomy/ laminectomy Figure 1B. Trends in Rates of Discectomy/Laminectomy and Fusion, Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery

4 Medicare spending for inpatient spine surgery more than doubled over the decade (Figure 2). Spending for lumbar discectomy and laminectomy (adjusted for inflation to year 2000 dollars) declined by more than 10%, from $342 million in 1992 to $306 million in Spending for lumbar fusion, by contrast, increased more than 500% during the same period, from $75 million to $482 million. In 1992, lumbar fusion represented 14% of total spending for spine surgery; by 2003, lumbar fusion accounted for 47% of spending. $1,100 Total reimbursements (millions) (adjusted for inflation to 2000 dollars) $1,000 $900 $800 $700 $600 $500 $400 $300 $200 $100 Other Non-lumbar discectomy/ laminectomy Non-lumbar fusion Lumbar fusion laminectomy $ Figure 2. Inpatient Medicare Reimbursements (in millions of dollars: adjusted for inflation to 2000 dollars) for Spine Surgery, Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery

5 Regional Variation in Rates of Spine Surgery Total Spine Surgery There was substantial regional variation in overall spine surgery rates among in (Figure 3). Rates varied by a factor of almost six, from 1.6 per 1,000 enrollees to 9.4. Among the hospital referral regions where rates of spine surgery were highest were Casper, Wyoming (9.4); Mason City, Iowa (9.0); Bend, Oregon (8.7); Boise, Idaho (8.2); and Billings, Montana (8.0). Regions with rates lower than the national average of 4.0 spine surgery procedures per 1,000 enrollees included Honolulu (1.6); Newark, New Jersey (1.7); Paterson, New Jersey (1.8); Manhattan (1.8); and East Long Island, New York (1.8) Ratio of Total Rates of Spine Surgery to the U.S. Average by Hospital Referral Region ( ) 1.30 to 2.36 (71) 1.10 to < 1.30 (56) 0.90 to < 1.10 (80) 0.75 to < 0.90 (47) 0.40 to < 0.75 (52) Not Populated Spine surgery per 1,000 ( ) Each point represents the rate in one of the 306 HRRs in the United States. Figure 3. Rates of Spine Surgery Among Hospital Referral Regions, Map 1. Spine Surgery In 71 hospital referral regions, rates of spine surgery were at least 30% higher than the United States average of 4.0 per 1,000. In 52 hospital referral regions, rates were more than 25% lower than the national average. Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery

6 Lumbar Discectomy and Laminectomy Rates of lumbar discectomy and laminectomy varied almost eightfold among in (Figure 4). Among the hospital referral regions where rates were highest were Mason City, Iowa (4.8); Slidell, Louisiana (4.7); Casper, Wyoming (4.6); Bend, Oregon (4.6); and Billings, Montana (4.5). Regions with rates lower than the national average of 2.1 procedures per 1,000 enrollees included the Bronx, New York (0.6); Honolulu (0.7); East Long Island, New York (0.8); Manhattan (0.9); and South Bend, Indiana (0.9) Ratio of Rates of Lumbar Discectomy and Laminectomy to the U.S. Average by Hospital Referral Region ( ) 1.30 to 2.28 (79) 1.10 to < 1.30 (52) 0.90 to < 1.10 (65) 0.75 to < 0.90 (55) 0.28 to < 0.75 (55) Not Populated 0.5 laminectomy per 1,000 ( ) Each point represents the rate in one of the 306 HRRs in the United States. Figure 4. Rates of Lumbar Discectomy and Laminectomy Among Hospital Referral Regions, Map 2. Lumbar Discectomy and Laminectomy In 79 hospital referral regions, rates of lumbar discectomy and laminectomy were at least 30% higher than the United States average of 2.1 per 1,000. In 55 hospital referral regions, rates were more than 25% lower than the national average. Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery

7 Lumbar Fusion The regional variation in rates of lumbar fusion among in was striking (Figure 5). Rates varied by a factor of more than twenty, from 0.2 per 1,000 enrollees to 4.6. Rates of lumbar fusion were highest in the Idaho Falls, Idaho (4.6); Missoula, Montana (3.0); Mason City, Iowa (3.0); Bradenton, Florida (2.9); and Casper, Wyoming (2.7) hospital referral regions. Regions with rates substantially lower than the national average of 1.0 procedure per 1,000 enrollees included Bangor, Maine (0.2); Covington, Kentucky (0.3); Terre Haute, Indiana (0.3); Grand Forks, North Dakota (0.3); and Newark, New Jersey (0.4) Ratio of Rates of Lumbar Fusion to the U.S. Average by Hospital Referral Region ( ) 1.30 to 4.48 (80) 1.10 to < 1.30 (41) 0.90 to < 1.10 (53) 0.75 to < 0.90 (33) 0.21 to < 0.75 (98) Insufficient data (1) Not Populated Lumbar fusion per 1,000 ( ) Each point represents the rate in one of the 306 HRRs in the United States. Figure 5. Rates of Lumbar Fusion Among Hospital Referral Regions, Map 3. Lumbar Fusion In 80 hospital referral regions, rates of lumbar fusion were at least 30% higher than the United States average of 1.0 per 1,000. In 98 hospital referral regions, rates were more than 25% lower than the national average. Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery

8 Non-Lumbar Discectomy and Laminectomy Rates of non-lumbar discectomy and laminectomy varied more than fivefold among in (Figure 6). Among the hospital referral regions where rates were highest were Billings, Montana (0.51); Fort Myers, Florida (0.43); St. Paul, Minnesota (0.42); Toledo, Ohio (0.42); and Houston (0.41). Regions with rates lower than the national average of 0.25 procedures per 1,000 enrollees included Honolulu (0.10); Marshfield, Wisconsin (0.10); Manhattan (0.10); Colorado Springs (0.11); and Modesto, California (0.12) Ratio of Rates of Non-Lumbar Discectomy and Laminectomy to the U.S. Average by Hospital Referral Region ( ) 1.30 to 2.08 (32) 1.10 to < 1.30 (36) 0.90 to < 1.10 (35) 0.75 to < 0.90 (30) 0.38 to < 0.75 (46) Insufficient data (127) Not Populated Non-lumbar discectomy/laminectomy per 1,000 ( ) Each point represents the rate in one of the 306 HRRs in the United States. Figure 6. Rates of Non-Lumbar Discectomy and Laminectomy Among Hospital Referral Regions, Map 4. Non-Lumbar Discectomy and Laminectomy In 32 hospital referral regions, rates of non-lumbar discectomy and laminectomy were at least 30% higher than the United States average of 0.25 per 1,000. In 46 hospital referral regions, rates were more than 25% lower than the national average. Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery

9 Non-Lumbar Fusion Rates of non-lumbar fusion varied by a factor of more than fifteen among in (Figure 7). Rates of non-lumbar fusion were highest in the Montgomery, Alabama (1.70); Dothan, Alabama (1.57); Charleston, South Carolina (1.29); Boise, Idaho (1.20); and Muskegon, Michigan (1.17) hospital referral regions. Regions with rates lower than the national average of 0.49 procedures per 1,000 enrollees included Rochester, Minnesota (0.11); Lebanon, New Hampshire (0.13); Allentown, Pennsylvania (0.14); Paterson, New Jersey (0.19); and Ridgewood, New Jersey (0.19) Ratio of Rates of Non-Lumbar Fusion to the U.S. Average by Hospital Referral Region ( ) 1.30 to 3.48 (61) 1.10 to < 1.30 (37) 0.90 to < 1.10 (44) 0.75 to < 0.90 (51) 0.22 to < 0.75 (78) Insufficient data (35) Not Populated Non-lumbar fusion per 1,000 ( ) Each point represents the rate in one of the 306 HRRs in the United States. Figure 7. Rates of Non-Lumbar Fusion Among Hospital Referral Regions, Map 5. Non-Lumbar Fusion In 61 hospital referral regions, rates of non-lumbar fusion were at least 30% higher than the United States average of 0.49 per 1,000. In 78 hospital referral regions, rates were more than 25% lower than the national average. Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery

10 Rates of fusion surgery and rates of discectomy/laminectomy were positively correlated, for both the lumbar and non-lumbar areas of the spine, among hospital referral regions in (Figures 8 and 9). There was also a strong correlation between lumbar and non-lumbar fusion rates (Figure 10). There was no association between the changes in lumbar discectomy and laminectomy rates and lumbar fusion rates from to (Figure 11). While in some regions a decline in lumbar discectomy and laminectomy was associated with an increase in lumbar fusion, overall the measures were unrelated (R 2 =.00). laminectomy ( ) R 2 = Non-lumbar discectomy/laminectomy ( ) R 2 = Lumbar fusion ( ) Non-lumbar fusion ( ) Figure 8. The Relationship Between Rates of Lumbar Discectomy/ Laminectomy and Lumbar Fusion, Figure 9. The Relationship Between Rates of Non-Lumbar Discectomy/ Laminectomy and Non-Lumbar Fusion, Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 10

11 Non-lumbar fusion ( ) Change in lumbar fusion rates, to (%) R 2 = R 2 = Lumbar fusion ( ) Change in lumbar discectomy/laminectomy rates, to (%) Figure 10. The Relationship Between Rates of Lumbar and Non-Lumbar Fusion, Figure 11. The Relationship Between Changes in Rates of Lumbar Discectomy/Laminectomy and Lumbar Fusion, to Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 11

12 Though lumbar fusion increased much more sharply than lumbar discectomy and laminectomy, rates of both procedures in were predictive of rates in (Figures 12 and 13). 44% of the variation in lumbar discectomy and laminectomy rates among HRRs in was predicted by the variation in , while 28% of the variation in lumbar fusion rates in was associated with the variation in Among non-lumbar procedures, 29% of the variation in rates of discectomy and laminectomy in was associated with the variation in (R 2 = 0.29), while 39% of the variation in fusion rates was predicted by the variation in (R 2 = 0.39) (figures not shown). Overall, 47% of the variation in total spine surgery rates in was predicted by rates in (R 2 =.47) (Figure 14) laminectomy ( ) Lumbar fusion ( ) Spine surgery ( ) R 2 = R 2 = R 2 = laminectomy ( ) Lumbar fusion ( ) Spine surgery ( ) Figure 12. The Relationship Between Rates of Lumbar Discectomy/Laminectomy in and Figure 13. The Relationship Between Rates of Lumbar Fusion in and Figure 14. The Relationship Between Rates of Total Spine Surgery in and The 45-degree line represents equality between rates; if the dot representing an HRR is located above the line, enrollees in that HRR experienced higher rates of utilization in than in Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 12

13 Overall rates of spine surgery in were not correlated with the per-capita supply of orthopedic and neurosurgeons in hospital referral regions in 1999 (the latest year for which workforce data are available) (Figures 15 and 16). Rates of lumbar and non-lumbar discectomy/laminectomy and fusion were also not correlated with the supply of either type of surgeon (Table 1) Spine surgery per 1,000 Medicare enrollees ( ) Spine surgery per 1,000 Medicare enrollees ( ) R 2 = R 2 = Orthopedic surgeons per 100,000 residents (1999) Neurosurgeons per 100,000 residents (1999) Figure 15. The Relationship Between Orthopedic Surgeons per 100,000 Residents (1999) and Rates of Spine Surgery ( ) Figure 16. The Relationship Between Neurosurgeons per 100,000 Residents (1999) and Rates of Spine Surgery ( ) able 1. Relationships (R2) Between the Supply of Surgeons (1999) and Rates of Surgery ( ) Table 1. Associations (R 2 ) Between the Supply of Surgeons (1999) and Rates of Surgery ( ) Lumbar discectomy/ laminectomy Lumbar fusion Non-lumbar discectomy/ laminectomy Orthopedic surgeons Neurosurgeons Non-lumbar fusion Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 13

14 Areas of Interest The Dartmouth Atlas of Health Care reports, from time to time, on such topics as changes in rates of surgical procedures or geographic patterns of utilization that appear to be exceptional, either because the rates have changed more than would be expected, or because the rates are remarkably higher or lower than the state and national averages. Lumbar Discectomy and Laminectomy in Billings, Montana The table beneath the graph gives the rates of lumbar discectomy and laminectomy in the Billings, Montana HRR and in United States from 1992 to The national average rate of lumbar discectomy and laminectomy rose between 1992 and 2001, from 1.7 procedures per 1,000 in 1992 to 2.2 in The rate then decreased slightly, to 2.1 per 1,000 in The U.S. average rate showed an overall increase of 23% during the period. In the Billings HRR, however, the rate of lumbar discectomy and laminectomy, which was about 21% higher than the national average in 1992, rose sharply from 1993 to 1994, when the rate was 3.0 per 1,000. The rate dropped between 1994 and 1995, then increased again. In 2001, the Billings HRR attained the rate of 4.6 procedures per 1,000 enrollees, more than twice the national average. The rate fell slightly, to 4.5 procedures per 1,000, between 2001 and The Billings rate of lumbar discectomy and laminectomy increased 119% over the decade. laminectomy per 1,000 Billings HRR United States average Number of procedures > U.S. avg U.S. rank in year Figure 17. Trends in Rates of Lumbar Discectomy and Laminectomy in the Billings, Montana HRR The table also gives the Billings HRR s national ranking in rates of lumbar discectomy and laminectomy during the decade and estimates the number of procedures in excess of the national average during the time period. In 1992, Billings ranked 87th among the 306 HRRs in the United States. When the rate was at its highest, in 2001, Billings ranked 5th; and, in 2003, Billings became the highest-ranked HRR in the country for lumbar discectomy and laminectomy procedures. Had the national average rate of lumbar discectomy and laminectomy prevailed in the Billings HRR, 21 fewer procedures would have been done in In 2001, had the U.S. rate prevailed, 160 fewer procedures would have been done; and in 2003, 163 fewer procedures would have been done had the rate in Billings been the same as the average rate in the United States. Between 1992 and 2003, there would have been 1,084 fewer lumbar discectomy and laminectomy procedures among residents of the Billings HRR had the U.S. average rate prevailed during the entire period. Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 14

15 Lumbar Fusion in Sarasota, Florida The table beneath the graph gives the rates of lumbar fusion in the Sarasota, Florida HRR and in United States from 1992 to The rate of lumbar fusion in Sarasota was about 50% higher than the national average in The rate increased 47% between 1992 and 1993, fell to below its 1992 level in 1994, and then climbed again, reaching 1.18 procedures per 1,000 in This rate was 2.7 times the national average. After declining to 1.05 procedures per 1,000 enrollees in 1997, the rate rose steadily. In 2003, the rate of lumbar fusion in the Sarasota HRR was 2.48 per 1,000 ; this rate was more than twice the national average. The rate of lumbar fusion in Sarasota increased by a factor of five from 1992 to 2003, while the U.S. average more than tripled. The table also gives the Sarasota HRR s ranking in rates of lumbar fusion among the 306 HRRs in the United States and estimates the number of procedures in excess of the national average for each year from 1992 to In 1992, Sarasota ranked 20th in rates of lumbar fusion per 1,000 Medicare enrollees. In 1996, Sarasota had the highest rate in the country; since then, its rate has remained in the top ten in every year except 2001, when it dropped to 12th. T Lumbar fusion per 1,000 Sarasota HRR United States average Number of procedures > U.S. avg U.S. rank in year Figure 18. Trends in Rates of Lumbar Fusion in the Sarasota HRR Had the national average rate of lumbar fusion prevailed in the Sarasota HRR in 1992, 15 fewer procedures would have been done. In 1996, there would have been 69 fewer lumbar fusions; and in 2003, 138 fewer lumbar fusion procedures would have been done had the rate in Sarasota been the same as the average rate in the United States. Between 1992 and 2003, there would have been 730 fewer lumbar fusion procedures among residents of the Sarasota HRR had the U.S. average rate prevailed during the entire period. Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 15

16 Methods Hospital referral regions (HRRs) are aggregations of hospital service areas (HSAs). A hospital service area is a collection of ZIP codes whose residents receive most of their hospitalizations from the hospitals within that area. Hospital referral regions represent regional health care markets for tertiary medical care; each HRR contains at least one hospital that performs major cardiovascular procedures and neurosurgery. The Medicare population in an area that was used as the denominator for the rates in these studies included those alive, age 65 to 99, and not enrolled in a risk bearing HMO. The numerator for the surgical rates presented was based on all individuals meeting these eligibility criteria who underwent the specified procedure during an inpatient stay within the given year, based on the ICD-9-CM procedure codes shown in the table. Rates based on a count of fewer than 11 observed counts are not displayed for reasons of patient confidentiality. Rates with fewer than 26 expected events are reported in parentheses to indicate lack of statistical precision; the margin of error is greater than 20%. Rates were adjusted to the age, sex and race distribution of the national Medicare population as follows. The national event rate for each agesex-race category was computed. These rates were then applied to the HSA and HRR populations to produce the expected number of events in the HSA or HRR; that is, the number of events that would have occurred in the HSA if its rate had been the same as the national event rate. Procedure Procedure Codes Inclusions & Exclusions Total spine surgery 03.0, 03.02, 03.09, 03.6; 78.50, 78.59, 78.60, 78.69, 78.90, 78.99; 80.5, , 80.59; 81.0, EXCLUDES Diagnosis codes , 324.1, , , , 733.1, , , , 733.8, , , , E800- E849.9 laminectomy 03.0, 03.09, 80.5, , See lumbar fusion for Inclusions Non-lumbar discectomy/ laminectomy Lumbar fusion ; also 81.04, 81.05, 81.09, 81.00, 81.0 with inclusions Non-lumbar fusion ; also 81.04, 81.05, 81.09, 81.00, 81.0 with exclusions 03.0, 03.09, 80.5, , See non-lumbar fusion for Exclusions INCLUDES Diagnosis codes , ; 721.3, ; , ; 724.6, 738.4, ; , , 724.2, 739.3, 739.4, , 847.2, EXCLUDES Diagnosis codes , ; 721.3, ; , ; 724.6, 738.4, ; , , 724.2, 739.3, 739.4, , 847.2, Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 16

17 Age-Sex-Race Adjusted Rates of Spine Surgery Among Medicare Enrollees by U.S. Hospital Referral Region Hospital referral region name Medicare enrollees, Spine surgery per 1,000 Notes: When rates were based on observed counts of 11 or fewer individuals in the HRR, the rates are fully suppressed and the cell in this table is empty. When a rate is based on fewer than 26 expected events, and might lack statistical stability, the rate is presented in parentheses. Lumbar fusion per 1,000 Non-lumbar discectomy/ Non-lumbar fusion per 1, AL-Birmingham 495, AL-Dothan 96, (0.24) (0.41) 1.57 AL-Huntsville 129, (0.13) 0.18 (0.21) 0.47 AL-Mobile 163, AL-Montgomery 100, (0.49) (0.41) (0.65) 1.70 AL-Tuscaloosa 59, (0.49) 0.74 (0.20) (0.26) (0.26) 0.79 AK-Anchorage 74, (0.36) 0.71 (0.16) (0.40) 0.36 AZ-Mesa 120, (0.21) 0.24 (0.19) 0.44 AZ-Phoenix 416, AZ-Sun City 89, (0.21) (0.16) 0.34 AZ-Tucson 187, AR-Fort Smith 90, (0.17) (0.21) (0.23) 0.68 AR-Jonesboro 61, (0.31) 0.51 (0.23) (0.29) 0.61 AR-Little Rock 392, AR-Springdale 102, (0.19) (0.27) 0.38 AR-Texarkana 67, (0.38) 0.54 (0.45) (0.21) 0.89 CA-Orange County 323, CA-Bakersfield 119, (0.19) 0.30 (0.28) 0.45 CA-Chico 79, (0.30) 0.74 (0.30) (0.31) (0.24) 0.43 CA-Contra Costa County 109, CA-Fresno 148, CA-Los Angeles 965, Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 17

18 Hospital referral region name Medicare enrollees, Spine surgery per 1,000 Lumbar fusion per 1,000 Non-lumbar discectomy/ Non-lumbar fusion per 1, CA-Modesto 115, CA-Napa 62, (0.18) 0.77 (0.27) (0.29) (0.19) 0.54 CA-Alameda County 149, CA-Palm Springs/Rancho Mirage 68, (1.22) 1.46 (0.33) (0.26) (0.35) 0.62 CA-Redding 91, (0.22) (0.25) (0.44) 0.50 CA-Sacramento 304, CA-Salinas 72, (0.52) 0.91 (0.26) (0.31) (0.36) 0.69 CA-San Bernardino 197, CA-San Diego 359, CA-San Francisco 194, CA-San Jose 165, CA-San Luis Obispo 54, (0.46) 0.93 (0.85) (0.54) CA-San Mateo County 107, (0.30) CA-Santa Barbara 74, (0.51) 1.20 (0.25) (0.56) (0.38) 0.84 CA-Santa Cruz 39, (0.23) (0.46) (0.25) (0.34) CA-Santa Rosa 66, (0.14) (0.29) (0.21) 0.32 CA-Stockton 70, (0.30) (0.16) 0.31 CA-Ventura 108, (0.27) 0.36 (0.68) 0.57 CO-Boulder 31, (0.71) 2.12 (0.49) (0.87) CO-Colorado Springs 126, (0.20) 0.11 (0.23) 0.34 CO-Denver 270, CO-Fort Collins 54, (1.77) 2.04 (0.47) (0.29) (0.47) 0.63 CO-Grand Junction 70, (0.86) 1.32 (0.22) (0.24) 0.57 CO-Greeley 61, (1.18) 1.97 (0.39) (0.59) (0.53) 0.71 CO-Pueblo 36, (1.02) 1.85 (0.28) (0.41) (0.51) CT-Bridgeport 144, Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 18

19 Hospital referral region name Medicare enrollees, Spine surgery per 1,000 Lumbar fusion per 1,000 Non-lumbar discectomy/ Non-lumbar fusion per 1, CT-Hartford 373, CT-New Haven 336, DE-Wilmington 161, DC-Washington 472, FL-Bradenton 97, (0.30) (0.33) (0.14) 0.93 FL-Clearwater 146, FL-Fort Lauderdale 581, FL-Fort Myers 367, FL-Gainesville 118, (0.10) 0.36 (0.40) 0.82 FL-Hudson 135, FL-Jacksonville 272, FL-Lakeland 88, (0.26) (0.19) 0.52 FL-Miami 341, FL-Ocala 210, FL-Orlando 794, FL-Ormond Beach 100, (0.23) (0.47) 0.84 FL-Panama City 52, (0.47) 1.81 (0.48) (1.00) FL-Pensacola 180, FL-Sarasota 196, FL-St. Petersburg 106, (0.14) FL-Tallahassee 155, FL-Tampa 188, GA-Albany 44, (0.30) (0.49) (0.72) GA-Atlanta 769, GA-Augusta 136, (0.10) 0.21 (0.28) 0.68 GA-Columbus 69, (0.23) 1.42 (0.20) (0.31) (0.27) 1.05 Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 19

20 Hospital referral region name Medicare enrollees, Spine surgery per 1,000 Lumbar fusion per 1,000 Non-lumbar discectomy/ Non-lumbar fusion per 1, GA-Macon 152, GA-Rome 65, (0.39) 0.85 (0.21) (0.32) 0.56 GA-Savannah 160, HI-Honolulu 267, ID-Boise 142, ID-Idaho Falls 38, (1.25) 4.56 (0.36) (1.14) IL-Aurora 32, (0.35) IL-Blue Island 197, IL-Chicago 415, IL-Elgin 106, (0.30) 0.75 (0.23) (0.21) (0.14) 0.31 IL-Evanston 243, IL-Hinsdale 76, (0.48) 0.71 (0.22) (0.61) 0.36 IL-Joliet 117, (0.18) 0.34 (0.12) 0.34 IL-Melrose Park 262, IL-Peoria 178, IL-Rockford 177, IL-Springfield 249, IL-Urbana 101, (0.25) (0.24) 0.32 IL-Bloomington 35, (0.41) (1.18) IN-Evansville 193, IN-Fort Wayne 207, IN-Gary 119, (0.21) 0.24 (0.29) 0.56 IN-Indianapolis 607, IN-Lafayette 46, (0.23) 0.83 (0.59) IN-Muncie 44, (0.36) 0.99 (0.31) (0.38) IN-Munster 76, (0.20) (0.26) (0.20) 0.45 Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 20

21 Hospital referral region name Medicare enrollees, Spine surgery per 1,000 Lumbar fusion per 1,000 Non-lumbar discectomy/ Non-lumbar fusion per 1, IN-South Bend 167, IN-Terre Haute 49, (0.22) (0.23) IA-Cedar Rapids 74, (0.35) 0.51 (0.20) (0.30) (0.16) 0.36 IA-Davenport 139, IA-Des Moines 276, IA-Dubuque 45, (0.24) (0.31) IA-Iowa City 81, (0.20) (0.28) 0.44 IA-Mason City 51, (0.46) (0.48) IA-Sioux City 76, (0.63) 1.65 (0.33) (0.23) 0.86 IA-Waterloo 62, (0.29) 1.42 (0.39) 0.37 KS-Topeka 113, (0.21) KS-Wichita 343, KY-Covington 67, (0.18) 0.26 (0.29) (0.41) 0.28 KY-Lexington 323, KY-Louisville 382, KY-Owensboro 37, (0.32) 0.87 (0.82) (0.34) (0.74) KY-Paducah 111, (0.31) 0.19 (0.36) 0.68 LA-Alexandria 68, (0.22) (0.24) 0.88 LA-Baton Rouge 128, LA-Houma 51, (0.43) (0.50) LA-Lafayette 120, (0.24) 0.32 (0.23) 0.52 LA-Lake Charles 60, (0.28) 0.97 (0.25) (0.36) 0.71 LA-Metairie 72, (0.22) 0.41 LA-Monroe 67, (0.30) 0.75 (0.32) (0.44) (0.21) 0.38 LA-New Orleans 102, (0.11) LA-Shreveport 167, Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 21

22 Hospital referral region name Medicare enrollees, Spine surgery per 1,000 Lumbar fusion per 1,000 Non-lumbar discectomy/ Non-lumbar fusion per 1, LA-Slidell 32, (0.59) (1.00) ME-Bangor 117, (0.17) 0.18 (0.15) 0.25 ME-Portland 275, MD-Baltimore 550, MD-Salisbury 124, (0.21) 0.13 (0.19) 0.38 MD-Takoma Park 146, (0.21) 0.37 (0.20) 0.51 MA-Boston 938, MA-Springfield 158, MA-Worcester 97, (0.14) MI-Ann Arbor 276, MI-Dearborn 130, MI-Detroit 421, MI-Flint 120, (0.11) 0.14 (0.11) 0.67 MI-Grand Rapids 245, MI-Kalamazoo 161, MI-Lansing 155, (0.27) 0.21 (0.20) 0.39 MI-Marquette 64, (0.27) MI-Muskegon 70, (0.30) 1.23 (0.22) (0.45) 1.17 MI-Petoskey 55, (0.24) 2.04 (0.46) 0.59 MI-Pontiac 83, (0.32) 0.94 (0.38) (0.25) (0.20) 0.37 MI-Royal Oak 168, MI-Saginaw 190, MI-St. Joseph 39, (0.35) (0.33) MI-Traverse City 73, (0.52) 1.69 (0.22) (0.21) (0.19) 0.47 MN-Duluth 103, (0.17) (0.23) (0.16) 0.28 MN-Minneapolis 614, Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 22

23 Hospital referral region name Medicare enrollees, Spine surgery per 1,000 Lumbar fusion per 1,000 Non-lumbar discectomy/ Non-lumbar fusion per 1, MN-Rochester 114, (0.17) MN-St. Cloud 56, (0.28) 0.63 MN-St. Paul 165, MS-Gulfport 41, (0.35) (0.50) (0.87) MS-Hattiesburg 66, (0.21) (0.24) 0.74 MS-Jackson 236, MS-Meridian 52, (0.62) MS-Oxford 35, (0.31) MS-Tupelo 91, (0.21) (0.32) (0.28) 0.49 MO-Cape Girardeau 74, (0.17) (0.26) (0.35) 0.50 MO-Columbia 177, MO-Joplin 100, (0.35) (0.28) (0.18) 0.46 MO-Kansas City 439, MO-Springfield 209, MO-St. Louis 667, MT-Billings 133, (0.23) 0.51 (0.21) 0.78 MT-Great Falls 41, (0.49) 2.17 (0.38) (0.53) MT-Missoula 93, (0.13) (0.48) (0.20) 1.03 NE-Lincoln 155, NE-Omaha 293, NV-Las Vegas 210, NV-Reno 130, (0.26) 0.30 (0.14) 0.93 NH-Lebanon 113, (0.11) 0.24 (0.14) 0.13 NH-Manchester 185, NJ-Camden 672, NJ-Hackensack 283, Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 23

24 Hospital referral region name Medicare enrollees, Spine surgery per 1,000 Lumbar fusion per 1,000 Non-lumbar discectomy/ Non-lumbar fusion per 1, NJ-Morristown 214, NJ-New Brunswick 198, NJ-Newark 287, NJ-Paterson 76, (0.18) 0.19 NJ-Ridgewood 89, (0.20) 0.19 NM-Albuquerque 256, NY-Albany 437, NY-Binghamton 110, (0.13) NY-Bronx 147, NY-Buffalo 278, NY-Elmira 102, (0.10) (0.17) 0.42 NY-East Long Island 861, NY-Manhattan 694, NY-Rochester 236, NY-Syracuse 268, NY-White Plains 232, NC-Asheville 200, NC-Charlotte 419, NC-Durham 300, NC-Greensboro 120, (0.15) 0.20 (0.21) 0.86 NC-Greenville 188, NC-Hickory 68, (0.39) 1.52 (0.28) (0.27) (0.31) 0.43 NC-Raleigh 302, NC-Wilmington 98, (0.28) 1.37 (0.29) (0.36) (0.38) 0.95 NC-Winston-Salem 221, ND-Bismarck 63, (0.20) 1.01 (0.31) (0.22) 0.39 Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 24

25 Hospital referral region name Medicare enrollees, Spine surgery per 1,000 Lumbar fusion per 1,000 Non-lumbar discectomy/ Non-lumbar fusion per 1, ND-Fargo/Moorhead MN 143, ND-Grand Forks 46, (0.59) 0.32 (0.33) ND-Minot 37, OH-Akron 137, OH-Canton 143, OH-Cincinnati 311, OH-Cleveland 495, OH-Columbus 583, OH-Dayton 257, OH-Elyria 56, (0.25) 0.94 (0.18) (0.19) 0.41 OH-Kettering 88, (0.20) (0.29) 0.58 OH-Toledo 215, OH-Youngstown 167, OK-Lawton 48, (0.25) 1.29 (0.22) (0.32) (1.09) OK-Oklahoma City 399, OK-Tulsa 265, OR-Bend 36, (0.41) 2.36 (0.86) (0.36) (1.08) OR-Eugene 171, OR-Medford 135, (0.21) 0.32 (0.54) 0.47 OR-Portland 298, OR-Salem 35, (0.54) 1.13 (0.24) (0.37) (0.40) (0.38) PA-Allentown 287, PA-Altoona 69, (0.14) (0.30) 0.24 PA-Danville 135, PA-Erie 192, PA-Harrisburg 252, Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 25

26 Hospital referral region name Medicare enrollees, Spine surgery per 1,000 Lumbar fusion per 1,000 Non-lumbar discectomy/ Non-lumbar fusion per 1, PA-Johnstown 54, (0.14) (0.23) (0.14) (0.41) PA-Lancaster 148, PA-Philadelphia 653, PA-Pittsburgh 627, PA-Reading 144, PA-Sayre 55, (0.26) PA-Scranton 96, (0.12) (0.20) (0.18) 0.23 PA-Wilkes-Barre 82, (0.23) (0.12) 0.30 PA-York 106, (0.13) (0.28) (0.11) 0.44 RI-Providence 206, SC-Charleston 203, SC-Columbia 244, SC-Florence 81, (0.40) 1.37 (0.19) (0.28) (0.30) 1.26 SC-Greenville 198, SC-Spartanburg 89, (0.26) 0.46 SD-Rapid City 51, (0.29) 2.10 (0.23) (1.05) SD-Sioux Falls 227, TN-Chattanooga 157, TN-Jackson 91, (0.15) (0.19) (0.12) 0.44 TN-Johnson City 61, (0.26) 0.33 TN-Kingsport 119, (0.16) TN-Knoxville 308, TN-Memphis 360, TN-Nashville 490, TX-Abilene 86, (0.13) (0.22) 0.66 TX-Amarillo 105, (0.49) (0.40) (0.27) 0.97 Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 26

27 Hospital referral region name Medicare enrollees, Spine surgery per 1,000 Lumbar fusion per 1,000 Non-lumbar discectomy/ Non-lumbar fusion per 1, TX-Austin 197, TX-Beaumont 109, (0.22) 0.37 (0.14) 0.70 TX-Bryan 41, (0.34) (0.40) (0.33) TX-Corpus Christi 102, (0.13) (0.28) 0.44 TX-Dallas 619, TX-El Paso 197, TX-Fort Worth 270, TX-Harlingen 93, (0.23) (0.26) 0.74 TX-Houston 802, TX-Longview 50, (0.32) 1.58 (0.36) (0.40) (1.05) TX-Lubbock 155, TX-McAllen 84, (0.31) (0.32) 0.35 TX-Odessa 71, (0.19) 1.22 (0.22) (0.84) (0.25) 1.10 TX-San Angelo 42, (0.36) 2.40 (1.30) (0.26) (0.98) TX-San Antonio 388, TX-Temple 75, (0.31) 0.81 (0.25) 0.34 TX-Tyler 146, TX-Victoria 40, (0.32) (0.40) TX-Waco 83, (0.15) (0.28) (0.46) 0.63 TX-Wichita Falls 56, (0.26) 1.15 (0.23) (0.20) 0.56 UT-Ogden 67, (1.45) 1.54 (0.16) (0.64) 0.67 UT-Provo 62, (0.76) 1.80 (1.03) 1.13 UT-Salt Lake City 309, VT-Burlington 150, VA-Arlington 264, VA-Charlottesville 133, (0.11) Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 27

28 Hospital referral region name Medicare enrollees, Spine surgery per 1,000 Lumbar fusion per 1,000 Non-lumbar discectomy/ Non-lumbar fusion per 1, VA-Lynchburg 70, (0.39) 0.48 (0.28) (0.39) 0.25 VA-Newport News 120, (0.44) 0.33 (0.38) 0.98 VA-Norfolk 247, VA-Richmond 341, VA-Roanoke 193, VA-Winchester 91, (0.35) 1.27 (0.17) (0.21) 0.46 WA-Everett 85, (0.25) (0.25) 0.37 WA-Olympia 64, (0.41) 1.40 (0.23) (0.17) 0.54 WA-Seattle 411, WA-Spokane 327, WA-Tacoma 111, (0.24) 0.27 (0.18) 0.42 WA-Yakima 57, (0.39) WV-Charleston 251, WV-Huntington 101, (0.16) (0.13) (0.11) 0.26 WV-Morgantown 106, (0.13) (0.23) (0.11) 0.30 WI-Appleton 80, (0.48) 0.85 (0.16) (0.15) 0.25 WI-Green Bay 134, (0.18) 0.32 (0.09) 0.47 WI-La Crosse 82, (0.22) 0.25 WI-Madison 237, WI-Marshfield 108, (0.14) WI-Milwaukee 572, WI-Neenah 62, (0.60) 0.98 (0.28) (0.33) 0.27 WI-Wausau 55, (0.39) WY-Casper 47, (0.69) 2.73 (0.47) (0.69) (0.30) (1.08) US-United States 56,935, Dartmouth Atlas of Health Care: Studies of Surgical Variation Spine Surgery 28