Facet joint intervention rates for spinal disorders increased dramatically over the study period from 1997 to 2006. This increase per 100,000 Medicare population from 1997 to 2006 was relatively constant over time, resulting in an increase of facet joint patients of 386%, facet joint visits of 446%, and facet joint interventions of 543%. Facet joint interventions also increased based on age. Among Medicare recipients per 100,000, less than 65 years of age, compared to those 65 or older, the patient population receiving facet joint interventions increased 504% vs. 355%, visits increased 587% compared to 404%, and services increased 683% compared to 498%. In addition, total expenditures also increased from over $229 million in 2002 to over $511 million in 2006, with an overall increase of 123% from 2002 to 2006. There was a significant increase of 1,109% in the utilization of facet joint interventions by general physicians -- composed of general practice, family practice, and internal medicine -- from 2002 to 2006, an annual increase of 277.3%. There were also significant usage or utilization increases among NPs and CRNAs from 2002 to 2006 of 398%, an annual increase of 99.5%. These increases were substantially higher than any other specialty, even though overall increases were significant: 160% from 2002 to 2006, an annual increase of 40%.
There was a 26.8-fold difference in the utilization pattern in Florida from Hawaii, the state with the lowest pattern for 2006. The remaining 49 states showed less than a 10-fold difference. Further, it has been shown that 47% of facet joint interventions in Florida were performed by general physicians. There has been an exponential growth of facet joint interventions in office settings of 271% with ASC settings showing 168% growth and HOPD settings showing 40% growth. However, moving the procedures to hospital settings will not resolve the issue as the average cost of the total procedure in HOPD settings in 2006 was $467.80, whereas in in-office settings, it was $227.60 and in ASC settings, it was $352.20.
Fluoroscopy utilization was lowest among family and general practice and internal medicine physicians and highest among pain management specialties. Non-fluoroscopically guided procedures present multiple issues regarding the accuracy of the procedure, medical necessity, and documentation.
With respect to evidence for facet joint interventions, there is emerging evidence to show the effectiveness of medial branch blocks and radiofrequency neurotomy along with effective diagnosis, when patients are selected appropriately meeting indications and medical necessity criteria [20–28]. While this evidence is emerging, some systematic reviews  have not utilized these trials [26–28] in their evidence synthesis.
Friedly et al  postulated that there was a disproportionate increase in procedures in ACSs, and that ACSs received higher payments. The implication is that these procedures had been shifted to ACSs as self referrals. Also that there was excessive use by facilitating physician investors to increase practice revenues by receiving facility payments for procedures. However, our study shows that this is not an issue. Rather, it may be due to the providing of more efficient services as a result of specialized staff and equipment, and convenient locations with short waiting times as well as better physician production. Further, the data illustrates that the procedures are more expensive in HOPD settings compared to ASC settings.
Based on the current data, it appears that the annual increase in the population with chronic low back pain is 11.6% , and the increase in facet joint intervention visits is approximately 50%. The increases are much lower in states with stricter regulations and LCDs [34, 35]. Kentucky showed an annual increase of 25% and Indiana, 26%; whereas the annual increase in Florida was 95%. The overall increase across the country was 40% from 2002 to 2006.
McKinsey Global Institute  postulated multiple factors for the increased growth of outpatient health care services in the United States. First, provider capacity growth and response to high outpatient margins is illustrated in this study based on significant increases in in-office settings and also performing these procedures. Other causes are that in outpatient settings, more efficient services are provided as a result of specialized staff and equipment, convenience of the location, short waiting times, and better physician production [34, 35]. The second factor relates to judgment based on the nature of physician care. Over the years there has been significant growth in interventional pain management due to increased understanding and to the availability of a supply of physicians. The third factor described relates to technological innovation that drives prices higher rather than lower , which is not proven in this study in the Medicare population in the United States. The fourth factor relates to demand growth that appears to be due to the greater availability of supplies. While this is accurate, there is also demand due to access and also to the increasing prevalence of spinal pain. The final factor relates to relatively price-insensitive patients with limited out-of-pocket costs. This factor may be realistic in the overall health care evaluation. However, in the Medicare population, the application of this is minimal. In this study we included only the patients who were paying fee-for-service. Thus, price insensitivity does not apply. However, the study of the patients with third party insurance with low out-of-pocket costs and workers' compensation patients with no out-of-pocket costs and Medicare Advantage patients with low out-of-pocket costs or no out-of-pocket costs will illustrate these differences. Yet numerous problems continue to exist with overuse and abuse.
There are multiple limitations to our study. These include the lack of inclusion of participants in Medicare Advantage plans, which includes approximately 10% of enrollees, and potential coding errors [3, 31]. However, we have included all patients over 65 receiving traditional fee-for-service Medicare and under 65 as well. This inclusion is important because patients below the age of 65 represent a significant proportion of patients receiving facet joint interventions, with a higher frequency of services. In general, patients less than 65 years of age received more intense and a higher proportion of services (504% vs. 355%) . This fact is echoed in this evaluation, which shows an increase of facet joint services of 683% vs. 498% from 1997 to 2006. Since the data does not contain HOPD facility charges, we had to estimate the facility charges for outpatient hospital charges, similar to Friedly et al . Another limitation is that some variation may be related to coding errors and diagnostic ambiguity, and to non-reporting of fluoroscopy. However, due to the usage of actual data for physicians, ASCs, and office services, these errors should have very little influence.
Multiple recommendations have been made to slow the growth of health care costs in general and for interventional techniques in particular [1, 4, 36]. Health care experts have recommended policies that encourage high-growth or high-cost regions to behave more like slow-growth, low-cost regions and to encourage low-cost, slow-growth regions to sustain their current needs for interventional techniques to slow spending growth. The OIG  has recommended strengthening program efforts to prevent improper payments; others  have also recommended more stringent regulations on medical necessity, indications, accreditation provisions in the settings performed, and training and qualifications of the physicians performing the procedures.