National Health Statistic Report

National Health Statistics Reports Number 102  February 28, 2017

Ambulatory Surgery Data From Hospitals and Ambulatory Surgery Centers: United States, 2010 by Margaret J. Hall, Ph.D., Alexander Schwartzman, Jin Zhang, and Xiang Liu, Division of Health Care Statistics

Abstract Introduction Objectives—This report presents national estimates of surgical and nonsurgical This report presents nationally ambulatory procedures performed in hospitals and ambulatory surgery centers (ASCs) representative estimates of ambulatory in the United States during 2010. Patient characteristics, including age, sex, expected surgery performed in hospitals and payment source, duration of surgery, and discharge disposition are presented, as well ambulatory surgery centers (ASCs) as the number and types of procedures performed in these settings. gathered by the 2010 National Hospital Methods—Estimates in this report are based on ambulatory surgery data collected Ambulatory Medical Care Survey in the 2010 National Hospital Ambulatory Medical Care Survey (NHAMCS). (NHAMCS). Ambulatory surgery, NHAMCS has collected outpatient department and emergency department data since also called outpatient surgery, refers 1992 and began gathering ambulatory surgery data from both hospitals and ASCs in to surgical and nonsurgical procedures 2010. Sample data were weighted to produce annual national estimates. that are nonemergency, scheduled in Results—In 2010, 48.3 million surgical and nonsurgical procedures were advance, and generally do not result in an performed during 28.6 million ambulatory surgery visits to hospitals and ASCs overnight hospital stay. combined. For both males and females, 39% of procedures were performed on those Ambulatory surgery has increased in aged 45–64. For females, about 24% of procedures were performed on those aged the United States since the early 1980s 15–44 compared with 18% for males, whereas the percentage of procedures performed (1,2). Two factors that contributed to this on those under 15 was lower for females than for males (4% compared with 9%). increase were medical and technological About 19% of procedures were performed on those aged 65–74, while about 14% advancements, including improvements were performed on those aged 75 and over. Private insurance was listed as the in anesthesia and in analgesics for the principal expected source of payment for 51% of ambulatory surgery visits, Medicare relief of pain, and the development and for 31% of visits, and Medicaid for 8% of visits. The most frequently performed expansion of minimally invasive and procedures included endoscopy of large intestine (4.0 million), endoscopy of small noninvasive procedures (such as laser intestine (2.2 million), extraction of lens (2.9 million), insertion of prosthetic lens surgery, laparoscopy, and endoscopy) (2.6 million), and injection of agent into spinal canal (2.9 million). Only 2% of visits (3–6). Before these advances, almost with a discharge status were admitted to the hospital as an inpatient. all surgery was performed in inpatient settings. Any outpatient surgery was Keywords: outpatient surgery • procedures • ICD–9–CM • National Hospital likely to have been minor, performed Ambulatory Medical Care Survey (NHAMCS) in physicians’ offices, and paid for by Medicare and insurers as part of the physician’s office visit reimbursement.

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention National Center for Health Statistics Page 2 National Health Statistics Reports  Number 102  February 28, 2017

The above advances and concerns performed in hospitals is now called location sample response rate was 87.5% about rising health care costs led to hospital outpatient department surgery. unweighted, and 86.9% weighted. The changes in the Medicare program in Facilities independent of hospitals that overall hospital response rate was 72.2% the early 1980s that encouraged growth specialize in ambulatory surgery are now unweighted and 79.0% weighted. In all, in ambulatory surgery. Medicare known as ASCs. 18,469 PRFs for ambulatory surgery expanded coverage to include surgery Independent samples of hospitals visits were submitted by hospitals. performed in ASCs (both hospital- and ASCs were drawn for the NHAMCS The ASCs that qualified for based and freestanding). In addition, a ambulatory surgery component. The inclusion in the 2010 NHAMCS (the prospective payment system for hospitals NHAMCS hospital sample (11) was universe) only included facilities in the based on diagnosis-related groups selected using a multistage probability 2006 NSAS sample. This sample was was adopted, and that created strong design, first sampling geographic units drawn in 2005 from a universe consisting financial incentives for hospitals to shift and then hospitals. Locations within the of facilities listed in the 2005 Verispan some surgery out of the hospital (1–5). hospital where the services of interest (later called SDI Health and then IMS Ambulatory surgery proved to be popular were provided, in this case ambulatory Health) Freestanding Outpatient Surgery among both physicians and patients surgery, were sampled next. Lastly, Center Database (13) or the Centers for (3,4,7,8), and the number of Medicare- patient visits within these locations were Medicare & Medicaid Services’ (CMS) certified ASCs increased steadily, from sampled. Medicare Provider of Services file (14). 239 in 1983 to 5,316 in 2010 (9,10). The hospitals that qualify for Using both of these sources resulted in This report covers ambulatory inclusion in this survey (the universe) a list of facilities that were regulated or surgery performed in hospitals and include noninstitutional hospitals licensed by the states and those certified ASCs that are independent of hospitals. (excluding federal, military, and by CMS for Medicare participation. Ambulatory surgery procedures Department of Veterans Affairs hospitals) More details about the 2006 NSAS performed in physicians’ offices and located in the 50 states and the District sample have been published elsewhere independent screening or diagnostic of Columbia. Only short-stay hospitals (2). Selection of the 2010 ASC sample centers were not included in this report. (hospitals with an average length of stay began with the NSAS 2006 stratified list for all patients of fewer than 30 days), sample of 472 FSASCs, which had strata those with a general specialty (medical defined by four geographic regions and Methods or surgical), and children’s general were 17 facility specialty groups. Seventy-four included in the survey. These hospitals facilities were out-of-scope, leaving 398 Data source and sampling must also have six or more beds staffed facilities from which to select the 2010 design for patient use. The 2010 NHAMCS NHAMCS ASC sample. To the extent hospital sample frame was constructed possible, the ASC sample was selected Data for this analysis are from from the products of SDI Health’s from the NHAMCS geographic sampling the ambulatory surgery component “Healthcare Market Index,” which was units. The 17 specialty group strata used of the 2010 NHAMCS, a nationally updated July 15, 2006, and its “Hospital in the 2006 NSAS sample were collapsed representative survey of hospitals and Market Profiling Solution, Second into 5 strata (ophthalmic, gastrointestinal, ASCs conducted by the National Center Quarter, 2006” (12). These products were multispecialty, general, and other). for Health Statistics (NCHS). This formerly known as the SMG Hospital All of the in-scope 2006 NSAS survey has provided data on ambulatory Market Database. sample facilities located within the medical care services provided in hospital In 2010, the sample consisted of NHAMCS geographic sampling units emergency and outpatient departments 488 hospitals, of which 74 were were selected, yielding 216 facilities. since 1992. From 2010 through 2012, out-of-scope (ineligible) because they To achieve the desired 246 facilities, a NHAMCS gathered data on ambulatory went out of business or otherwise failed stratified list sample of 30 facilities was surgery procedures in both hospitals and to meet the criteria for the NHAMCS drawn from the remaining in-scope 2006 ASCs. In 2013, data collection in ASCs universe. Of the 414 in-scope (eligible) NSAS sample facilities that were located was suspended so a new sampling frame hospitals, 275 had eligible ambulatory outside of the NHAMCS geographic could be developed. Previously, during surgery locations. Of these, 227 sampling units. Strata were defined by 1994–1996 and in 2006, the National participated, yielding an unweighted the four regions and the five collapsed Survey of Ambulatory Surgery (NSAS) hospital ambulatory surgery response surgery specialty groups. gathered data from hospital-based ASCs rate of 82.6% and a weighted response There were 149 in-scope (eligible) (HBASCs) and from facilities independent rate of 90.9%. All of the 321 ambulatory ASCs and, of this number, 109 responded of hospitals [then called freestanding surgery locations within the 227 to the survey for an unweighted response ASCs (FSASCs)] (2). The terms HBASC participating hospitals were selected rate of 73.2% and a weighted response and FSASC are no longer in use because for sampling, and 281 of these fully or rate of 70.2%. In all, 8,492 PRFs were Medicare, and other insurers following adequately responded [at least one-half submitted for ASCs. Medicare’s lead, changed the name and of the number of expected patient record The overall response rate for nature of the reimbursement categories forms (PRFs) were completed]. The hospitals combined with ASCs was for these services. Ambulatory surgery resulting hospital ambulatory surgery 72.2% unweighted and 79.0% weighted. National Health Statistics Reports  Number 102  February 28, 2017 Page 3

The combined number of PRFs from both Bureau personnel acting on behalf of Based on the assumption that the of these settings was 26,961. NCHS. A PRF for each sampled visit was characteristics of ambulatory surgery Facilities were selected using a completed. A visit is defined as a direct visits probably do not vary with facility multistage probability design, with personal exchange between a physician age, the sample should enable the facilities having varying selection or a staff member operating under a measurement of 2010 characteristics (if probabilities. Patient visits to ASCs physician’s direction, for the purpose of not numbers) of ambulatory visits. To the and to locations in the hospital where seeking ambulatory surgery. Visits solely extent that the ASCs that existed in 2005 ambulatory surgery was provided were for administrative purposes and visits in were different from those in existence selected using systematic random which no medical care was provided are in 2010, these differences would not sampling procedures. out-of-scope. have been fully captured by the 2010 Within each sampled hospital, a The PRF contains items relating NHAMCS (17). sample of ambulatory surgery visits to the personal characteristics of the Due to limited resources, the was selected from all of the ambulatory patients, such as age, sex, race and sample sizes for hospitals and for ASCs surgery locations identified by hospital ethnicity, and administrative items, for the NHAMCS ambulatory surgery staff. These locations included main such as the date of the procedure, component were only about one-half of or general operating rooms; dedicated expected source(s) of payment, what they were for the 2006 NSAS, so ambulatory surgery units; cardiac and discharge disposition. Medical the most recent estimates have larger catheterization laboratories; and rooms information collected includes provider standard errors. This makes it more for endoscopy, laparoscopy, laser of anesthesia and type of anesthesia, difficult for differences to achieve procedures, and pain block. length of time in both the operating statistical significance. Locations within hospitals dedicated room and in surgery, symptoms present Until 2008, hospital ambulatory exclusively to abortion, dentistry, during or after the procedure, and up to surgery was included under Medicare’s podiatry, family planning, birthing, five diagnoses and seven procedures, HBASC payment category. Beginning in or small procedures were excluded, which were coded according to the 2008, Medicare discontinued its use of but these procedures were included International Classification of Diseases, this category and instead began paying if performed at in-scope locations. In Ninth Revision, Clinical Modification for hospital ambulatory surgery as part of ASCs with in-scope specialties, all visits (ICD–9–CM) (15). Information on up to hospital outpatient department services. were sampled. Facilities specializing 12 new or continuing prescription and Hospitals also dropped the HBASC in abortion, dentistry, podiatry, family over-the-counter drugs ordered, supplied, designation and, in some hospitals, planning, birthing, or small procedures or administered during the visit or at this change led to a greater dispersion were excluded, but these procedures were discharge was also collected, and these of ambulatory surgery procedures included if performed at in-scope ASCs. drugs were coded using Multum Lexicon throughout the hospitals, including To minimize response burden for (16), a proprietary drug classification to various parts of the outpatient hospitals and ASCs, the samples were system used by NCHS. departments and locations within medical divided into 16 nationally representative clinics. panels, and those panels were randomly Some hospitals had difficulty ordered for rotation over reporting Limitations of NHAMCS identifying all of the locations in the periods of 4 weeks each. Within the Ambulatory Surgery hospital where in-scope procedures were reporting periods, patient visits were performed, especially in the first year systematically selected. The visit lists Data of NHAMCS ambulatory surgery data could be sign-in sheets or appointment Limited resources did not permit collection (2009). This same year, after lists. The total targeted number of updating the ASC frame for the 2010 the problems became apparent, U.S. ambulatory surgery visit forms to be NHAMCS, so the NSAS 2006 sample, Census Bureau and NCHS staff provided completed in each hospital and in each based on ASCs in existence in 2005, additional information to field staff about ASC was 100. In facilities or hospitals was used. Based on annual data on the how to identify locations in the hospital with volumes higher than these desired number of Medicare-certified ASCs from that were in-scope and out-of-scope figures, visits were sampled by a CMS, the increase in the number of these for the ambulatory surgery component systematic procedure that selects every facilities was taken into account in the of NHAMCS. More formal training nth visit after a random start. Visit calculation of NHAMCS ASC survey material on this point was provided in sampling rates were determined from weights. The visit total related to the a 2010 training CD that was sent to all the expected number of patients to be increase in the number of ASCs was also field staff. These efforts are believed to seen during the reporting period and the accounted for in the weights, but any have corrected this problem. However, desired number of completed PRFs. possible change in the number of visits due to these issues, it is likely that some per ASC was not accounted for because in-scope procedures were undercounted Data collection no data were available on the number of in 2009 and 2010. visits to ASCs over time. Final weighting A number of changes occurred in Medical record abstraction was is described in more detail elsewhere (11). the health care system during 2008–2010 performed by facility staff or U.S. Census that could have affected the amount Page 4 National Health Statistics Reports  Number 102  February 28, 2017 of ambulatory surgery care that was Table A. Ambulatory surgery procedures and visits to hospitals and ambulatory surgery provided in settings covered by this centers: United States, 2010 report and the amount provided in Ambulatory surgery utilization Estimate Standard error out-of-scope settings (e.g., physicians’ offices). More information about the Procedures (millions) ...... 48.3 4.3 difficulties of gathering and comparing in hospitals ...... 25.7 2.6 in ASCs ...... 22.5 3.3 data on ambulatory surgery from these two time periods and surveys is Visits (millions) ...... 28.6 2.4 available (18). in hospitals ...... 15.7 1.6 in ASCs ...... 12.9 1.8

NOTE: ASC is ambulatory surgery center. Results SOURCE: NCHS, National Hospital Ambulatory Medical Care Survey, 2010.

Ambulatory surgery Table B. Percent distribution of ambulatory surgery visits in hospitals and ambulatory procedure and visit overview surgery centers, by discharge disposition: United States, 2010

● In 2010, 28.6 million ambulatory Discharge disposition Percent of visits surgery visits to hospitals and ASCs occurred (Table 1). During these Routine discharge1...... 95 2 visits, an estimated 48.3 million Observation status ...... 2 surgical and nonsurgical procedures Admission to hospital as inpatient ...... 2 Other3 ...... 1 were performed (Table 2). Total4 ...... 100 ● An estimated 25.7 million (53%) ambulatory surgery procedures were 1Discharge to customary residence, generally home. 2Discharge for further observation without being admitted to a hospital. performed in hospitals and 22.5 3Includes discharge to postsurgical or recovery care facility, referral to emergency department, surgery terminated, and other options. million (47%) were performed in 4Excludes 1.2 million of the 28.6 million total visits with an unknown discharge disposition. ASCs (Table A). SOURCE: NCHS, National Hospital Ambulatory Medical Care Survey, 2010. ● Private insurance was the expected payment source for 51% of the visits for ambulatory surgery, Medicare payment was expected for 31%, and Medicaid for 8%. Only 4% were Private 51 self-pay (Figure 1). insurance ● Ninety-five percent of the visits with a specified discharge disposition 31 had a routine discharge, generally Medicare to the patient’s home. Patients were t admitted to the hospital as inpatients Medicaid or 8 during only 2% of these visits ymen CHIP/SCHIP (Table B). of pa

ce Self-pay 4 Ambulatory surgery Sour procedures, by sex and age Other 4 ● For both males and females, 39% of procedures were performed on those aged 45–64 (Figure 2). Unknown 2 ● For females, about 24% of procedures were performed on those 01020304050 60 aged 15–44 compared with 18% for Percent of visits males, whereas the percentage of procedures performed on those under NOTE: CHIP is Children’s Health Insurance Program and SCHIP is State Children’s Health Insurance Program. SOURCE: NCHS, National Hospital Ambulatory Medical Care Survey, 2010. 15 was lower for females than for males (4% compared with 9%). Figure 1. Percent distribution of ambulatory surgery visits in hospitals and ambulatory ● About 19% of procedures were surgery centers, by principal expected source of payment: United States, 2010 performed on those aged 65–74, with about 14% performed on those aged 75 and over. National Health Statistics Reports  Number 102  February 28, 2017 Page 5

averaged 14 minutes, while endoscopic 50 Total Female Male polypectomy of the large intestine averaged 21 minutes. For cataract surgery, extraction or insertion of lens 39 39 39 (often done together) averaged 10 40 minutes, and operations on the eyelids averaged 23 minutes. Arthroscopy of the knee averaged 32 minutes.

edures 30

proc 24 22 Discussion

t of 20 19 en 20 18 18 Keeping in mind the limitations rc 15 that should be taken into account when

Pe 14 14 comparing 2006 NSAS data and 2010 9 NHAMCS ambulatory surgery data, 10 6 the 53.3 million ambulatory surgery 4 procedures estimated using 2006 NSAS data were compared with the 48.3 million ambulatory surgery procedures 1Under 15 115–44 45–64 65–74 75 and over estimated using 2010 NHAMCS data. Age group (years) The difference between these two 1Differences between females and males in these age groups are statistically significant. figures was not statistically significant. NOTES: Numbers may not add to totals because of rounding. See Table 2 in this report (NHSR 102, “Ambulatory Surgery Data From Hospitals and Ambulatory Surgery Centers: United States, 2010”) for standard errors. A significant decrease of 18% (from SOURCE: NCHS, National Hospital Ambulatory Medical Care Survey, 2010. 34.7 to 28.6 million) was seen in the Figure 2. Percent distribution of ambulatory surgery procedures in hospitals and number of ambulatory surgery visits ambulatory surgery centers, by age and sex: United States, 2010 during this same time period. It had been expected based upon the limited data that were available and on projections Types of procedures times for cataracts; and operations on from past trends, that there would have eyelids, performed 1.0 million times. been an increase in the numbers of both Seventy percent of the 48.3 million Musculoskeletal procedures included ambulatory surgery visits and procedures ambulatory surgery procedures were operations on muscle, tendon, fascia, and (9,10,19). included in the following clinical bursa (1.3 million). One reason for these findings could categories: operations on the digestive Operations on the integumentary be an undercount in NHAMCS in 2010. system (10 million or 21%), operations on system included excision or destruction Another reason that ambulatory surgery the eye (7.9 million or 16%), operations of lesion or tissue of skin and visit estimates could have decreased and on the musculoskeletal system subcutaneous tissue (1.2 million). ambulatory surgery procedures remained (7.1 million or 15%), operations on Operations on the nervous system steady, could be the deep economic the integumentary system (4.3 million included injection of agent into spinal recession that began in 2007. By 2010, or 9%), and operations on the nervous canal (2.9 million), including injections when NHAMCS began gathering system (4.2 million or 9%) (Table 3). for pain relief. ambulatory surgery data in both hospitals These procedure categories made up 72% and ASCs, the economy had not fully of procedures performed on females and Duration of surgery recovered. The rate of unemployment 67% of those performed on males. Within and the number of people who did not the above-mentioned categories, data The average time in the operating have health insurance were higher in on procedures performed more than 1 room for ambulatory surgery was almost 2010 compared with 2006, and both of million times are presented below. 1 hour (57 minutes). On average, about these factors could have affected patients’ Under operations on the digestive one-half of this time (33 minutes) was use of ambulatory surgery (20,21). Even system, endoscopy of large intestine— spent in surgery. Postoperative care for those who continued to have health which included colonoscopies—was averaged 70 minutes. Time spent in the insurance, increased out-of-pocket costs performed 4.0 million times, and operating room, surgery, and receiving (higher deductibles and coinsurance endoscopy of small intestine was postoperative care were all significantly payments) may have contributed to performed 2.2 million times. Endoscopic longer for ambulatory surgery performed a decrease in the number of visits for polypectomy of large intestine was in hospitals compared with ASCs ambulatory surgery (22). performed an estimated 1.1 million times. (Table C). An examination of various data Eye operations included extraction The average surgical times for sources, including Medicare, the American of lens, performed 2.9 million times; selected ambulatory surgery procedures Hospital Association, and NHAMCS, was insertion of lens, performed 2.6 million are shown in Table D. Endoscopies undertaken to evaluate if other national Page 6 National Health Statistics Reports  Number 102  February 28, 2017

Table C. Distribution of times for surgical visits, by ambulatory surgery facility type: United States, 2010

Hospital Ambulatory surgery center All facilities

Average time Standard Average time Standard Average time Standard Calculated time of ambulatory surgical visit (minutes) error (minutes) error (minutes) error

Operating room1...... 63 1.9 50 3.7 57 2.2 Surgical2 ...... 37 1.5 29 3.2 33 1.7 Postoperative care3 ...... 89 2.9 51 3.8 70 2.6

1Calculated by subtracting the time when the patient entered the operating room from the time the patient left the operating room. 2Calculated by subtracting the time the surgery began from the time the surgery ended. Surgical time typically extends from when the first incision is made until the wound is closed. 3Calculated by subtracting the time when the patient entered postoperative care from the time the patient left postoperative care. SOURCE: NCHS, National Hospital Ambulatory Medical Care Survey, 2010. data sources reached similar conclusions available from: ftp://ftp.cdc.gov/pub/ 5. Duffy SQ, Farley DE. Patterns of about trends in ambulatory surgery during Health_Statistics/NCHS/Datasets/ decline among inpatient procedures. 2006–2010 (19). This analysis revealed NHAMCS. The data base documentation Public Health Rep 110(6):674–81. that the only nationally representative for this file is available from:ftp://ftp. 1995. data during this time period were from cdc.gov/pub/Health_Statistics/NCHS/ 6. MEDPAC. Report to the Congress: the 2006 NSAS and the 2010 NHAMCS Dataset_Documentation/NHAMCS. Medicare payment policy. Section ambulatory surgery component. Medicare Among the options being explored F: Assessing payment adequacy and data on the number of certified ASCs for future data collection are the use of updating payments for ambulatory over time existed, but only limited both claims data and electronic health surgical center services. Washington, Medicare ambulatory surgery utilization record data. DC. 2003. and expenditure data were available, and 7. Durant GD. ASCs: Surviving, thriving almost all of it was from ASCs only and into the 1990s. Med Group Manage J did not include data on ambulatory surgery References 36(2):14. 1989. in hospitals. Even so, Medicare utilization 1. Leader S, Moon M. Medicare trends 8. KNG Health Consulting, LLC. and expenditure data could not have been in ambulatory surgery. Health Aff An analysis of recent growth of used to generalize to the entire population (Millwood) 8(1):158–70. 1989. ambulatory surgical centers: Final because Medicare only covers those aged 2. Cullen KA, Hall MJ, Golosinskiy A. report. Prepared for the ASC Coalition. 65 and over and people with disabilities. Ambulatory surgery in the United 2009. Close to 70% of ambulatory surgery States, 2006. National health statistics 9. MEDPAC. Report to the Congress: procedures were paid for by sources other reports; no 11. Hyattsville, MD: Medicare payment policy. Chapter 5: than Medicare. National Center for Health Statistics. Ambulatory surgical center services. 2009. Washington, DC. 2013. 10. MEDPAC. Report to the Congress: Ambulatory Surgery 3. Davis JE. Ambulatory surgery…how far can we go? Med Clin North Am Medicare payment policy. Washington, Data 77(2): 365–75. 1993. DC. 2012. 11. National Center for Health Statistics. The 2010 NHAMCS ambulatory 4. Lumsdon K, Anderson HJ, Burke M. New surgical technologies reshape 2010 NHAMCS public-use micro-data surgery data used for this report have file documentation.Available from: been released in a public-use file hospital strategies. Hospitals 66(9):30– 6. 1992. ftp://ftp.cdc.gov/pub/Health_Statistics/ NCHS/Dataset_Documentation/ NHAMCS. Table D. Average surgical duration for selected procedures: United States, 2010 12. Verispan LLC. Healthcare market Average index, updated July 15, 2006. surgical time Standard Hospital market profiling solution, Selected procedure1 ICD–9–CM codes (minutes)2 error second quarter. Chicago: Healthcare Endoscopy (including colonoscopy) ...... 45.11–45.14, 45.16, 45.21–45.25 14 0.87 Information Specialists. 2006. Endoscopic polypectomy of large intestine . . . . . 45.42 21 0.97 13. Verispan LLC. Freestanding outpatient Extraction or insertion of lens (cataracts) ...... 13.1–13.7 10 1.20 surgery centers database. Chicago: Operations on eyelids ...... 08 23 3.56 Healthcare Information Specialists. Arthroscopy of knee ...... 80.26 32 2.69 2005.

1Times were counted only for patients who had each of these selected procedures and no others during their ambulatory surgery 14. Centers for Medicare & Medicaid visit. Services. Provider of services file. 2Calculated by subtracting the time surgery began from the time surgery ended. Surgical time typically extends from when the first incision is made until the wound is closed. Baltimore, MD. 2005. NOTE: Procedure categories and code numbers are based on the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD–9–CM). SOURCE: NCHS, National Hospital Ambulatory Medical Care Survey, 2010. National Health Statistics Reports  Number 102  February 28, 2017 Page 7

15. Centers for Disease Control and Prevention, Centers for Medicare & Medicaid Services. International classification of diseases, ninth revision, clinical modification. 6th ed. DHHS Pub No. (PHS) 11–1260. 2011. Available from: https://www.cdc.gov/ nchs/icd/icd9cm.htm. 16. Cerner Multum, Inc. Cerner Multum Lexicon. Available from: http://www. multum.com/lexicon.html. 17. Shimizu I. Sampling design for the 2010–2012 National Hospital Ambulatory Medical Care Survey. In: Proceedings from the 2011 JSM Annual Meeting. Alexandria, VA: American Statistical Association. 2012. 18. Hall MJ. The challenges of gathering and interpreting national data on ambulatory surgery over time. Proceedings from the 2013 JSM Annual Meeting. Alexandria, VA: American Statistical Association. 2014. 19. Hall MJ. Comparison of national data on ambulatory surgery from CDC’s National Hospital Ambulatory Medical Care Survey, Medicare, the American Hospital Association and SDI. Proceedings from the 2014 JSM Annual Meeting. Alexandria, VA: American Statistical Association. 2015. 20. Alliance for Health Reform Briefing: Trends in health insurance coverage in the U.S.: The impact of the economy. 2010. Available from: http://www.allhealth.org/ briefingmaterials/TrendsinHealth InsuranceTranscript12-6-2010-1923. pdf. 21. Kaiser Family Foundation, Commission on Medicaid and the Uninsured. The uninsured: A primer— Key facts about health insurance on the eve of health reform. 2013. Available from: https://kaiserfamilyfoundation. files.wordpress.com/2013/10/7451- 09-the-uninsured-a-primer-key-facts- about-health-insurance.pdf. 22. Manchikanti L, Parr AT, Singh V, Fellows B. Ambulatory surgery centers and interventional techniques: A look at long-term survival. Pain Physician 14(2):E177–215. 2011. 23. RTI International. SUDAAN (Release 9.0.1) [computer software]. 2005. Page 8 National Health Statistics Reports  Number 102  February 28, 2017

Table 1. Number and percent distribution of ambulatory surgery visits, by age and sex: United States, 2010

Both sexes Female Male

Age group (years) Estimate Standard error Estimate Standard error Estimate Standard error

Number (thousands) Total ...... 28,588 2424 16,481 1,365 12,108 1,084 Under 15 ...... 1,812 302 712 122 1,100 184 15–44 ...... 6,426 619 4,201 411 2,225 223 45–64...... 10,911 1,010 6,256 555 4,659 474 65–74 ...... 5,301 446 2,951 242 2,350 213 75 and over ...... 4,139 360 2,365 205 1,774 167

Percent distribution Total ...... 100 … 100 … 100 … Under 15 ...... 6 0.86 4 0.62 9 1.21 15–44 ...... 23 0.94 26 1.06 18 0.91 45–64...... 38 0.89 38 0.84 39 1.16 65–74 ...... 19 0.67 18 0.69 19 0.84 75 and over ...... 14 0.69 14 0.72 15 0.83

... Category not applicable. NOTE: Numbers may not add to totals because of rounding. SOURCE: NCHS, National Hospital Ambulatory Medical Care Survey, 2010. National Health Statistics Reports  Number 102  February 28, 2017 Page 9

Table 2. Number and percent distribution of ambulatory surgery procedures, by age and sex: United States, 2010

Both sexes Female Male

Age group (years) Estimate Standard error Estimate Standard error Estimate Standard error

Number (thousands) Total ...... 48,263 4,253 27,595 2,373 20,669 1,932 Under 15 ...... 2,916 500 1,118 199 1,798 310 15–44 ...... 10,478 1,014 6,708 631 3,770 418 45–64...... 18,783 1,876 10,789 1,060 7,994 857 65–74 ...... 9,153 802 5,053 423 4,100 403 75 and over ...... 6,933 619 3,926 356 3,007 285

Percent distribution Total ...... 100 ... 100 ... 100 ... Under 15 ...... 6 0.82 4 0.57 9 1.20 15–44 ...... 22 0.89 24 0.92 18 1.10 45–64...... 39 1.02 39 1.05 39 1.23 65–74 ...... 19 0.79 18 0.78 20 1.00 75 and over ...... 14 0.80 14 0.84 15 0.89

... Category not applicable. NOTE: Numbers may not add to totals because of rounding. SOURCE: NCHS, National Hospital Ambulatory Medical Care Survey, 2010. Page 10 National Health Statistics Reports  Number 102  February 28, 2017 * * * * * * * * * * * * * * – 75 82 88 66 * 54 * 37 * 58 * * 38 220 431 158 590 453 325 245 2,646 1,043 1,173 1,198 6,933 75 and over * * * * * * * * * * * – 89 91 81 80 36 83 54 294 916 276 951 166 354 631 437 113 387 104 356 2,697 1,081 2,044 9,153 65–74 * * * * * 86 72 83 58 * 40 * 30 131 527 456 240 482 511 575 135 520 162 116 126 936 155 584 355 198 369 2,122 2,132 1,981 1,313 4,759 45–64 18,783 Age group (years) group Age * * * * * * * * * 98 83 66 72 82 88 * 40 311 321 689 106 175 164 102 474 196 172 468 128 712 126 178 1,093 1,002 1,826 15–44 10,478 * * * * * * * * * * * * * * * * * * * * * * * * * – – 93 69 * 67 699 903 289 847 2,916 Number (thousands) Under 15 * * – – – 66 51 * 40 141 759 525 431 193 178 371 612 112 214 241 575 111 203 861 260 581 553 Male 3,258 1,027 1,290 1,785 1,841 1,156 1,330 4,627 20,669 Sex – 78 * 32 * 55 * 52 141 590 323 205 266 651 442 179 192 106 485 325 198 328 152 136 219 196 519 1,766 4,622 1,526 1,117 2,202 1,312 2,385 1,705 1,588 5,418 Female 27,595 72 282 525 754 399 444 190 393 433 106 172 436 198 328 302 339 479 777 449 Total 1,349 1,766 7,880 1,021 2,553 1,054 2,407 3,987 1,060 2,172 4,226 2,861 2,918 1,072 10,045 48,263 (08) (22) (21.6) (21.8) (13.7) (28.6) (69.0) (51.23) (20.01) (68.12) (04.43) (42.92) (45.42) (08–16) (18–20) (30–34) (55–59) (60–64) (65–71) (21–29) (13.1–13.6) (28.2–28.3) (37.21–37.23) (57.31–57.33) (01–05,17.61) (45.21–45.25) (03.91–03.92) (45.11–45.14,45.16) (21.1,21.3–21.4,21.6) (53.0–53.9,17.1–17.2) (53.0–53.1,17.1–17.2) (42–54,17.1–17.3,17.63) (33.21–33.24,33.27,33.71–33.73,33.78–33.79) � � � � � (35–39,00.40–00.49,00.50–00.55,00.57,00.61–00.66,17.51–17.52,17.71) � � � � � � � � Procedure category and ICD–9–CM code Procedure � � � � � � � � � . � � � � � � � � � � (pseudophakos) � �

� � � � � � � � � � � � � Turbinectomy Repair of inguinal herniaRepair Bronchoscopy with or without biopsy Bronchoscopy Hysteroscopy Cystoscopy with or without biopsy Cystoscopy Endoscopy of small intestine with or without biopsy of small intestine Endoscopy intestine of large Endoscopic polypectomy Operations on eyelids Operations of lens Extraction and destruction of nose and lesion Incision, excision on the nose and plastic operations Repair on nasal sinuses Operations with or without adenoidectomy Tonsillectomy without tonsillectomy Adenoidectomy cholecystectomy Laparoscopic Hernia repair of uterus Dilation and curettage Myringotomy with insertionMyringotomy of tube Injection of agent into spinal canal spinal canal Injection of agent into of carpalRelease tunnel with or without biopsy intestine of large Endoscopy Insertion lens of prosthetic Dilation of esophagus Cardiac catheterization Cardiac See footnotes at end of table. See footnotes Table 3. Number of ambulatory surgery procedures in hospitals and ambulatory surgery centers, by procedure category, sex, and age: United States, 2010—Con. States, United and age: sex, category, procedure by surgery centers, in hospitals and ambulatory surgery procedures Number of ambulatory 3. Table Operations on the female genital organs genital on the female Operations Operations on the eye Operations Operations on the ear Operations mouth, and pharynx on the nose, Operations Operations on the respiratory system on the respiratory Operations Operations on the cardiovascular system on the cardiovascular Operations Operations on the digestive system on the digestive Operations organs on the male genital Operations Operations on the urinaryOperations system Operations on the nervous system on the nervous system Operations All procedures All procedures National Health Statistics Reports  Number 102  February 28, 2017 Page 11 * * * * * * * * * * 88 32 380 923 171 448 75 and over * * * * 80 * 40 * 62 * 48 * 55 * 29 566 105 196 182 885 1,158 65–74 * 86 87 333 435 635 151 449 135 111 127 165 141 1,767 2,358 3,456 45–64 Age group (years) group Age * * 64 64 49 254 196 319 323 104 160 120 201 1,497 1,225 2,114 15–44 * * * * * * * * * * * – * 52 131 228 173 Number (thousands) Under 15 * * 63 84 83 * 52 935 359 385 637 485 227 286 109 Male 2,790 3,275 Sex * * 332 374 636 734 285 153 183 111 327 285 132 3,405 3,102 3,802 Female * 692 759 268 348 380 267 195 379 571 241 Total 4,340 1,274 1,219 5,892 7,076 (77.5) (80.6) (80.26) (85.21) (85–86) (82–83) (86.2–86.4) (76.97,78.6) (76.96,81.92) (85.11–85.12) (76.7,79.0–79.3) (06–07,40–41,72–75) (76.2–76.3,77.6–77.8) (76–84,00.70–00.77,00.80–00.87) (81.42–81.47,81.54–81.55,00.80–00.84) � � � � � 00.58–00.59, 00.67–00.69,17.62,17.69,17.70,38.24,38.25,00.91–00.94,17.4) � � � � � � � Procedure category and ICD–9–CM code Procedure � (87–99,00.01–00.03,00.09–00.19,00.21–00.25,00.28–00.29,00.31–00.35,00.39, 00.56, (87–99,00.01–00.03,00.09–00.19,00.21–00.25,00.28–00.29,00.31–00.35,00.39, � � � � � � � � Biopsy of breast Biopsy Excision of semilunar cartilage of knee Excision of knee or other repair Replacement or destruction tissue of lesion or tissue skin and subcutaneous Excision Partial excision of bone Partial excision Injection of therapeutic substance into joint or ligament into substance Injection of therapeutic (lumpectomy) of lesion breast Local excision Removal of implanted devices from bone from devices of implanted Removal deformities and other toe of bunion and repair Excision of knee Arthroscopy Reduction of fracture Reduction and bursa fascia tendon, on muscle, Operations * Figure does not meet standards of reliability or precision. An asterisk with a number indicates that the estimate is based on a relatively small number of cases, and while reliable, should be used with caution. and while reliable, of cases, small number is based on a relatively that the estimate indicates with a number An asterisk or precision. of reliability does not meet standards * Figure – Quantity zero. (ICD–9–CM). Modification Clinical Revision, Ninth of Diseases, Classification based on the International are and code numbers categories Procedure NOTE: 2010. Survey, Medical Care Ambulatory National Hospital NCHS, SOURCE: Table 3. Number of ambulatory surgery procedures in hospitals and ambulatory surgery centers, by procedure category, sex, and age: United States, 2010—Con. States, United and age: sex, category, procedure by surgery centers, in hospitals and ambulatory surgery procedures Number of ambulatory 3. Table Operations on the endocrine system, on the hemic and lymphatic system, and system, on the hemic and lymphatic on the endocrineOperations system, Operations on the integumentary system Operations and procedures Miscellaneous diagnostic and therapeutic procedures obstetrical technologies new Operations on the musculoskeletal system on the musculoskeletal Operations Page 12 National Health Statistics Reports  Number 102  February 28, 2017 * * * * * * * * * * * * * * * *9 83 35 33 82 47 92 15 18 16 53 *17 *11 *15 *16 179 163 392 144 591 75 and over * * * * * * * * * * * * * – *9 35 77 49 19 74 24 17 69 60 90 21 14 11 132 133 124 322 278 105 765 65–74 * * * * * * *8 67 81 61 17 15 21 77 76 16 29 31 17 27 25 63 37 62 *11 101 319 106 297 318 106 144 377 599 45–64 1,806 Age group (years) group Age * * * * * * * * * 61 16 14 88 82 23 16 12 19 35 35 27 17 80 22 69 31 30 19 18 *11 145 208 240 196 972 15–44 * * * * * * * * * * * * * * * * * * * * * * * * * – – 53 14 21 Standard error Standard *20 194 184 152 492 Under 15 – – – 45 38 24 14 94 83 20 32 59 11 20 25 54 44 89 61 *10 173 108 114 106 265 280 454 100 159 147 316 128 555 109 Male 1,844 Sex * * * – *8 61 22 93 79 36 23 42 18 48 91 48 33 37 38 31 98 *12 155 223 305 292 107 569 130 217 213 398 171 608 2,250 Female 38 65 15 32 42 31 78 64 92 18 33 68 88 75 72 102 312 195 184 106 223 557 560 188 203 370 356 161 703 290 113 197 Total 1,005 1,148 4,040 (08) (22) (21.6) (21.8) (13.7) (28.6) (69.0) (51.23) (20.01) (68.12) (04.43) (42.92) (45.42) (08–16) (18–20) (21–29) (30–34) (55–59) (60–64) (65–71) (13.1–13.6) (28.2–28.3) (37.21–37.23) (57.31–57.33) (01–05,17.61) (03.91–03.92) (45.21–45.25) (45.11–45.14,45.16) (21.1,21.3–21.4,21.6) (53.0–53.9,17.1–17.2) (53.0–53.1,17.1–17.2) (42–54,17.1–17.3,17.63) (33.21–33.24,33.27,33.71–33.73,33.78–33.79) � � � � � (35–39,00.40–00.49,00.50–00.55,00.57,00.61–00.66,17.51–17.52,17.71) � � � � � � � � Procedure category and ICD–9–CM code Procedure � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � Turbinectomy Repair of inguinal herniaRepair Incision, excision and destruction of nose and lesion Incision, excision with or without biopsy Bronchoscopy with or without biopsy of small intestine Endoscopy intestine of large Endoscopic polypectomy cholecystectomy Laparoscopic with or without biopsy Cystoscopy Hysteroscopy Release of carpalRelease tunnel Adenoidectomy without tonsillectomy Adenoidectomy Extraction of lens Extraction Insertion lens (pseudophakos) of prosthetic with insertionMyringotomy of tube on the nose and plastic operations Repair on nasal sinuses Operations with or without adenoidectomy Tonsillectomy Hernia repair of uterus Dilation and curettage Operations on eyelids Operations Endoscopy of large intestine with or without biopsy intestine of large Endoscopy Injection of agent into spinal canal Injection of agent into Dilation of esophagus Cardiac catheterization Cardiac See footnotes at end of table. See footnotes Table 4. Standard errors of ambulatory surgery procedures in hospitals and ambulatory surgery centers, by procedure category, sex, and age: United States, 2010—Con. States, United and age: sex, category, procedure by surgery centers, in hospitals and ambulatory surgery procedures of ambulatory errors Standard 4. Table Operations on the female genital organs genital on the female Operations Operations on the eye Operations system on the respiratory Operations Operations on the ear Operations mouth, and pharynx on the nose, Operations system on the cardiovascular Operations Operations on the digestive system on the digestive Operations organs on the male genital Operations Operations on the urinaryOperations system Operations on the nervous system Operations All procedures All procedures National Health Statistics Reports  Number 102  February 28, 2017 Page 13 * * * * * * * * * * *9 19 51 48 77 123 75 and over * * * * *7 26 22 44 65 37 *10 *14 *15 *13 183 144 65–74 * 26 66 21 32 41 25 16 22 26 124 100 102 254 327 685 45–64 Age group (years) group Age * * 9 39 47 62 15 58 28 21 24 16 36 217 186 305 15–44 * * * * * * * * * * * – 32 50 36 Standard error Standard *10 Under 15 * * 91 96 56 20 14 36 15 66 18 *13 103 111 385 501 Male Sex * 80 79 39 43 69 45 19 27 80 27 113 423 103 376 667 Female * 39 58 72 50 50 37 35 168 177 201 496 129 750 141 Total 1,156 (77.5) (80.6) (80.26) (85.21) (82–83) (85–86) (86.2–86.4) (76.97,78.6) (76.96,81.92) (85.11–85.12) (76.7,79.0–79.3) (06–07,40–41,72–75) (76.2–76.3,77.6–77.8) (76–84,00.70–00.77,00.80–00.87) (81.42–81.47,81.54–81.55,00.80–00.84) � � � � � 00.58–00.59, 00.67–00.69,17.62,17.69,17.70,38.24,38.25,00.91–00.94,17.4) � � � � � � � Procedure category and ICD–9–CM code Procedure � (87–99,00.01–00.03,00.09–00.19,00.21–00.25, 00.28–00.29,00.31–00.35,00.39,00.56, (87–99,00.01–00.03,00.09–00.19,00.21–00.25, � � � � � � � � Replacement or other repair of knee or other repair Replacement Excision of semilunar cartilage of knee Excision of breast Biopsy Excision or destruction tissue of lesion or tissue skin and subcutaneous Excision Local excision of lesion of breast (lumpectomy) of lesion breast Local excision Partial excision of bone Partial excision bone from devices of implanted Removal of knee Arthroscopy Injection of therapeutic substance into joint or ligament into substance Injection of therapeutic deformities and other toe of bunion and repair Excision Operations on muscle, tendon, fascia and bursa fascia tendon, on muscle, Operations Reduction of fracture Reduction * Figure does not meet standards of reliability or precision. An asterisk with a number indicates that the estimate is based on a relatively small number of cases, and while reliable, should be used with caution. and while reliable, of cases, small number is based on a relatively that the estimate indicates with a number An asterisk or precision. of reliability does not meet standards * Figure – Quantity zero. (ICD–9–CM). Modification Clinical Revision, Ninth of Diseases, Classification based on the International are and code numbers categories Procedure NOTE: 2010. Survey, Medical Care Ambulatory National Hospital NCHS, SOURCE: Table 4. Standard errors of ambulatory surgery procedures in hospitals and ambulatory surgery centers, by procedure category, sex, and age: United States, 2010—Con. States, United and age: sex, category, procedure by surgery centers, in hospitals and ambulatory surgery procedures of ambulatory errors Standard 4. Table Operations on the integumentary system Operations Miscellaneous diagnostic and therapeutic procedures and procedures Miscellaneous diagnostic and therapeutic technologies new Operations on the endocrine system, on the hemic and lymphatic system, and system, on the hemic and lymphatic on the endocrineOperations system, procedures obstetrical Operations on the musculoskeletal system on the musculoskeletal Operations Page 14 National Health Statistics Reports  Number 102  February 28, 2017

Technical Notes (RTI International, Research Triangle be obtained if a complete census had Park, N.C.). been taken. The estimates shown in this Data processing and medical coding report include surgical procedures, such were performed by SRA International, Testing of significance and as tonsillectomy; diagnostic procedures, such as ultrasound; and other therapeutic Inc., Durham, N.C. Editing and rounding estimation were completed by the procedures, such as injection or infusion National Center for Health Statistics. Differences in the estimates were of cancer chemotherapeutic substance. evaluated using a two-tailed t test In 2010, up to seven procedures were coded for each visit. All listed Estimation (p < 0.05). Terms such as “higher than” and “less than” indicate that differences procedures include all occurrences of the Because of the complex multistage are statistically significant. Terms such procedure coded regardless of the order design of the National Hospital as “similar” or “no difference” indicate on the medical record. The procedure data in this report are Ambulatory Medical Care Survey that no statistically significant difference presented by chapter of the International (NHAMCS), the survey data must exists between the estimates being Classification of Diseases, Ninth be inflated or weighted to produce compared. A lack of comment on the Revision, Clinical Modification national estimates. The estimation difference between any two estimates (ICD–9–CM). In the Results section, procedure produces essentially unbiased does not mean that the difference was selected chapters with large numbers national estimates and has three basic tested and found not to be significant. of procedures are discussed along components: (a) inflation by reciprocals Estimates of counts in the tables with specific categories of procedures of the probabilities of sample selection, have been rounded to the nearest performed 1 million or more times. The (b) adjustment for nonresponse, and (c) thousand. Therefore, estimates within latter categories are included to give population weighting ratio adjustments. tables do not always add to the totals. some examples of what was included These three components of the final Rates and percentages were calculated under the chapters. weight are described in more detail from unrounded figures and may not Table 3 presents data using elsewhere (11). precisely agree with rates and percentages ICD–9–CM codes for chapters Because NHAMCS ambulatory calculated from rounded data. of procedures as well as selected surgery data are collected from a sample procedures within these chapters. The of visits, persons with multiple visits Nonsampling errors procedures selected for inclusion in during the year may be sampled more Table 3 were those with relatively large than once. Therefore, estimates are of As in any survey, results are subject frequencies, or because there was a the number of visits to, or procedures to both sampling and nonsampling errors. clinical, epidemiological, or health performed in, hospital ambulatory Nonsampling errors include reporting and services interest in them. surgery locations and ASCs, and not processing errors as well as biases due to Data from the 2010 NHAMCS the number of persons served by these nonresponse and incomplete response. showed that an estimated 479,000 facilities. The magnitude of the nonsampling errors ambulatory surgery visits ended with an cannot be computed. However, efforts admission to the hospital as an inpatient. Standard errors were made to keep these errors to a The visits made by these patients were minimum by building procedures into included in this report [as they were in The standard error is primarily the operation of the survey. To eliminate the 2006 National Survey of Ambulatory a measure of sampling variability ambiguities and encourage uniform Surgery (NSAS) Report] (2), and the that occurs by chance because only a reporting, attention was given to the ambulatory surgery procedures they sample, rather than the entire universe, phrasing of items, terms, and definitions. received were included in the estimates is surveyed. Estimates of the sampling Quality control procedures and for all listed procedures. variability for this report were calculated consistency and edit checks reduced Estimates were not presented in using Taylor approximations in errors in data coding and processing. this report if they were based on fewer SUDAAN, which take into account the A 5% quality control sample of survey than 30 cases in the sample data or if the complex sample design of NHAMCS. records was independently keyed and relative standard error (RSE) was greater A description of the software and the coded. Item nonresponse rates were than 30%. In these cases, only an asterisk approach it uses has been published generally low, but levels of nonresponse (*) appears in the tables. The RSE of elsewhere (23). The standard errors of did vary among different variables. The an estimate is obtained by dividing the estimates presented in the tables of this data shown in this report are based upon standard error by the estimate itself. The report are included, either as part of items with low nonresponse. result is then expressed as a percentage the table or, in the case of Table 3, in a of the estimate. Estimates based on 30 to 59 cases include an asterisk because, separate table (Table 4). Use of tables Data analyses were performed using while their RSE is less than 30%, these the statistical packages SAS, version 9.3 The estimates presented in this report estimates are based on a relatively small (SAS Institute, Cary, N.C.) and SAS- are based on a sample, and therefore number of cases and should be used with callable SUDAAN, version 10.0 may differ from the number that would caution. U.S. DEPARTMENT OF FIRST CLASS MAIL HEALTH & HUMAN SERVICES POSTAGE & FEES PAID CDC/NCHS Centers for Disease Control and Prevention PERMIT NO. G-284 National Center for Health Statistics 3311 Toledo Road, Room 4551, MS P08 Hyattsville, MD 20782–2064

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National Health Statistics Reports  Number 102  February 28, 2017

Suggested citation Copyright information National Center for Health Statistics Hall MJ, Schwartzman A, Zhang J, Liu X. All material appearing in this report is in Charles J. Rothwell, M.S., M.B.A., Director Ambulatory surgery data from hospitals and the public domain and may be reproduced Jennifer H. Madans, Ph.D., Associate Director ambulatory surgery centers: United States, or copied without permission; citation as to for Science 2010. National health statistics reports; no 102. source, however, is appreciated. Hyattsville, MD: National Center for Health Division of Health Care Statistics Statistics. 2017. Denys T. Lau, Ph.D., Acting Director Alexander Strashny, Ph.D., Associate Director for Science

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