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Routine Imaging for Anterior Cervical Decompression and Fusion Procedures: A Survey Study Establishing Current Practice Patterns Daniel D. Bohl, MPH; Joshua W. Hustedt, BA; Daniel J. Blizzard, BS; Raghav Badrinath, BS; Jonathan N. Grauer, MD
abstract Full article available online at Healio.com/Orthopedics. Search: 20120621-24 The number of anterior cervical decompression and fusion procedures performed annually in the United States rose 8-fold from 1990 to 2004. Imaging for anterior cervical decompression and fusion procedures contributes to health care costs and exposes patients and staff to radiation. Despite this, no standard of care for such imaging has been defined, and imaging practices have remained largely uncharacterized. The authors distributed a questionnaire at the 2011 Spine Study Group meeting. They received 72 responses (80% response rate) and included 67 in the analysis. All participants were attending spine surgeons practicing in the United States, 97% of whom had completed spine surgery fellowships. Median practice duration was 8 years. Practice type was evenly split between private and academic, and the median annual number of anterior cervical decompression and fusion procedures was 50. Intraoperatively, 68% of surgeons use fluoroscopy and 32% use plain radiographs; 60% take at least 1 image prior to incision; 78% place the localizer in the disk, whereas 22% place it in the vertebral body, and 45% always save these localizer images; 100% take images of the final construct before leaving the operating room, and 74% always save the finalconstruct images. Postoperatively but before discharge, 12% of surgeons take images in the recovery room, 33% take images in the radiology suite, and 2% take images in both locations. After discharge, surgeons follow their patients for a mean of 1.6 years, 96% with lateral views, 96% with anteroposterior views, 46% with flexion–extension radiographs, and 14% with computed tomography scans.
Messrs Bohl, Hustedt, Blizzard, and Badrinath and Dr Grauer are from the Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, Connecticut. Messrs Bohl, Hustedt, Blizzard, and Badrinath and Dr Grauer have no relevant financial relationships to disclose. Correspondence should be addressed to: Jonathan N. Grauer, MD, Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, 800 Howard Ave, New Haven, CT 06510 (jonathan.
[email protected]). doi: 10.3928/01477447-20120621-24
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Figure: Pie charts showing the intraoperative images routinely taken during anterior cervical decompression and fusion procedures. Type of imaging used in the operating room (top left). Images taken in the operating room prior to skin incision (top right). Images taken in the operating room to locate levels (middle left and right). Images taken in the operating room to check the final construct (bottom left and right).
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Imaging for Anterior Cervical Decompression and Fusion Procedures | Bohl et al
A
nterior cervical decompression and fusion is a surgical procedure regularly performed to decompress and stabilize the cervical spine. The number of procedures performed annually in the United States rose 8-fold from 1990 to 2004.1 As more patients undergo the procedure, it becomes increasingly important to maximize efficiency, minimize risk, and reduce associated costs. Imaging accounts for a large proportion of the yearly growth in health care costs in the United States.2 Among surgical specialties, spine surgery is particularly image intensive. Images are often taken intraoperatively, immediately postoperatively, and intermittently thoughout the follow-up period. However, no standard of care has been formally defined with respect to imaging for anterior cervical decompression and fusion procedures, and current imaging practices have remained largely uncharacterized. The purpose of this study was to characterize the intra- and postoperative imaging practices for anterior cervical decompression and fusion procedures among a representative sample of spine surgeons practicing in the United States.
Materials and Methods A single-page questionnaire was prepared to record the practices of spine surgeons regarding imaging for anterior cervical decompression and fusion procedures. The questionnaire consisted of 3 sets of questions. The first set inquired about intraoperative imaging practices, the second about postoperative imaging practices, and the third about the biographic information of those completing the questionnaire. After being preliminarily circulated among the physicians at the authors’ institution to ensure its consistency and design, the questionnaire was distributed to all individuals with MD or DO degrees attending the 22nd annual Organization of Spinal Teaching and Research Spine Study Group meeting (West Palm Beach,
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Florida, May 2011). Although this sample population largely comprised attending spine surgeons practicing in the United States, a limited number of other practitioners attended, and their data were excluded from the analysis. All questionnaires were immediately collected on site. Questionnaire data were analyzed using STATA version 11.0 (StataCorp, LP, College Station, Texas). First, frequencies were calculated for all variables. Second, the regional distribution of surgeons was compared with that observed for the general population in the 2009 U.S. Census3 using Pearson’s chi-square test. Finally, all imaging practice variables were individually tested for association with demographic variables, also using Pearson’s chi-square test. Statistical difference was established at a 2-sided a level of 0.05 (P,.05). The study was approved by the hospital investigations committee at the authors’ institution with a waiver for informed consent because the data collected were considered to be of minimal risk to study participants.
Results Ninety registrants with MD or DO degrees attended the conference, of whom 72 (80%) returned the questionnaires. At the time of analysis, 3 participants were excluded because they were residents or fellows, 1 because he or she no longer operated, and 1 because he or she did not practice in the United States, resulting in 67 participants (93% of returned questionnaires) included in the study population. Demographics of the study population are presented in the Table. All participants were attending spine surgeons practicing in the United States, 97% of whom completed spine surgery fellowships. Median practice duration was 8 years. The regional distribution of participants’ practices did not differ from the regional distribution of the general population (for the general population, Midwest522%, Northeast518%, South537%, West5
Table 1
Participant Demographics Demographic
Percenta
Spine surgery fellowship Not completed
3
Completed
97
Surgeon type Orthopedic
99
Neurosurgeon
1
Practice duration, y 0-4
33
5-9
27
>10
39
Practice location Midwest
22
Northeast
22
South
38
West
18
Practice type Private
45
Academic
45
Hybrid
11
ACDF procedures per y 1-49
44
50-99
35
>100
21
Abbreviation: ACDF, anterior cervical decompression and fusion. a Each section sums to 100%.
23%; P5.546). Practice type was evenly split between private and academic, and median number of anterior cervical decompression and fusion procedures was 50 per year. Routine intraoperative imaging practices are displayed in Figure 1. Sixty-eight percent of surgeons use fluoroscopy while operating, whereas 32% use plain radiographs. Sixty percent of surgeons take at least 1 image before making their initial skin incision. Seventy-eight percent of surgeons place their localizer in the intervertebral disk, whereas 22% place it
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in the vertebral body. Forty-five percent of surgeons always save these localizing images. All surgeons routinely view their final construct with imaging intraoperatively, and 74% of surgeons always save these images. Figure 2 shows that 47% of surgeons take images postoperatively but before discharge, whereas 53% do not. Twelve percent of surgeons take these images in the recovery room, 33% take them in the radiology suite, and 2% take them in both. Compared with surgeons who always save intraoperative images of their final constructs, surgeons who do not always save intraoperative images of their final constructs are no more or less likely to take images postoperatively but before discharge (P5.299). Imaging practices after patient discharge are presented in Figures 3 and 4. The median and mean times for which surgeons follow outpatients with imaging after anterior cervical decompression and fusion procedures are 1 and 1.6 years, respectively. Ninety-six percent of surgeons routinely follow postoperative outpatients with anteriorposterior views, 96% with lateral views, and 46% with flexion–extension images. Fourteen percent of surgeons routinely order computed tomography scans during the follow-up period. Of those who routinely obtain postoperative computed tomography scans, both the mean time and the median time after the procedure were 9 months, and the range was 6 months to 1 year. All correlations between imaging practice variables and demographic variables lacked statistical significance (P..05) with the exception of 2 variables (Figure 5). First, surgeons in private or hybrid practice are more likely to routinely take images in the operating room before making their initial skin incision compared with surgeons in academic practice (72% vs 43%; P5.018). Second, surgeons in private or hybrid practice are less likely to routinely take images postoperatively but before discharge compared with sur-
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geons in academic practice (26% vs 69%, respectively; P5.001).
Discussion The authors characterized practice patterns surrounding anterior cervical decompression and fusion procedures performed by spine surgeons in the United States by distributing a questionnaire at a spine surgery conference. The analyzed population of surgeons may be somewhat biased toward longer practice duration and academic practice type, with 2 of 5 participants having a practice duration of 10 or more years and approximately half of participants in academic practice. Nevertheless, the analyzed population of surgeons has comparable geographical distribution and is probably sufficiently similar to the population the authors intend to represent. The data presented describe many practice patterns and have a few clinical implications. The authors found that all surgeons take images intraoperatively, approximately two-thirds using fluoroscopy and one-third using plain radiography. Although fluoroscopy may be of slightly lower resolution than plain radiography, many surgeons prefer fluoroscopy because less time is wasted waiting for technicians and in developing images and because the real-time feedback provided by fluoroscopy can be helpful operatively and can help obtain adequate views. Four-fifths of surgeons place their localizer in the disk, whereas one-fifth places it in the vertebral body. This was interesting because placement of the localizer in the incorrect disk has been associated with adjacent-level disk degeneration.4 The finding may be due to surgeons’ lack of knowledge of the described association, easier placement of the needle into the disk space than into the vertebral body, or simple training bias. Approximately half of surgeons take images postoperatively but before discharge. Of those, one-fourth do so immediately postoperatively in the recovery room,
1 Figure 1: Pie charts showing the intraoperative images routinely taken during anterior cervical decompression and fusion procedures. Type of imaging used in the operating room (top left). Images taken in the operating room prior to skin incision (top right). Images taken in the operating room to locate levels (middle left and right). Images taken in the operating room to check the final construct (bottom left and right).
2 Figure 2: Pie chart showing the Images routinely taken postoperatively but before discharge after anterior cervical decompression and fusion procedures. Abbreviation: OR, operating room.
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Imaging for Anterior Cervical Decompression and Fusion Procedures | Bohl et al
Figure 3: Graph showing the length of time for which surgeons routinely followed outpatients with imaging after anterior cervical decompression and fusion (ACDF) procedures. Median time was 1 year and mean time was 1.6 years.
3 Figure 4: Chart showing Images routinely taken to follow outpatients after anterior cervical decompression and fusion procedures. Abbreviations: AP, anteroposterior; CT, computed tomography; Flex/ex, flexion– extension.
4 Figure 5: Graph showing how the imaging patterns vary across the surgeons’ type of practice. “Routinely image patients after OR but before discharge” indicates that surgeons routinely ordered images in the recovery room, the radiology suite, or both prior to discharge. P values are from Pearson’s chi-square test. Abbreviation: OR, operating room.
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whereas the other three-fourths do so in the forthcoming days in the radiology suite. A recent study reported that portable imaging in the recovery room after anterior cervical decompression and fusion has little clinical use due to its duplicity with intraop-
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erative imaging and due to the shoulders commonly obstructing the lateral view of the construct.5 That study, by suggesting that routine recovery room imaging be discontinued, challenges a relatively common practice.
Four of five surgeons routinely followed their postoperative outpatients with imaging for at least 1 year, nearly all with anteroposterior and lateral radiographs, and approximately half with flexion–extension radiographs. This is a large proportion in light of evidence that postoperative imaging on asymptomatic patients at regular intervals may have limited clinical use. Specifically, pseudarthrosis and construct failure following anterior cervical decompression and fusion procedures occur rarely, and patients with new symptoms postoperatively are as likely to have normal postoperative plain radiograph findings as they are to have abnormalities identified on their postoperative plain radiographs.6 In comparison with surgeons in academic practice, those in private or hybrid practice were more likely to routinely take images in the operating room before making their initial skin incision. In contrast, they were less likely to routinely take images postoperatively but before discharge. These findings might be explained by the academic teaching environment. In this environment, greater use of bony and muscular landmarks may facilitate teaching, taking the place of radiology. Similarly, postoperative radiographs allow for immediate feedback, which may be helpful for instruction. The current study had several weaknesses. First, as with any questionnaire study, the potential for sampling bias exists. In particular, the authors believe their population of spine surgeons has a greater practice duration and may be more academic than the population they are attempting to represent. Second, self-report data may be inferior to use data collected directly from hospital systems because a response bias might be introduced, potentially generating misleading results.
Conclusion In the era of evidence-based medicine, it is important to identify current practice patterns so that they can be compared
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against the scientific knowledge base. The growing proportion of health care dollars spent on imaging and the staggering growth in the number of anterior cervical decompression and fusion procedures performed in the United States make imaging for anterior cervical decompression and fusion procedures a critical area of study. The findings presented here should serve as a compass for future research into the use of routine imaging, which is critical to evolve evidence-based care.
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References 1. Marawar S, Girardi FP, Sama AA, et al. National trends in anterior cervical fusion procedures. Spine (Phila Pa 1976). 2010; 35(15):1454-1459. 2. Iglehart JK. The new era of medical imaging—progress and pitfalls. N Engl J Med. 2006; 354(26):2822-2828. 3. U.S. Census Bureau. The 2011 Statistical Abstract. The National Data Book. 2011. http:// www.census.gov/compendia/statab/2011/ tables/11s0012.xls. Accessed June 20, 2011. 4. Nassr A, Lee JY, Bashir RS, et al. Does incorrect level needle localization during anterior cervical discectomy and fusion lead to ac-
celerated disc degeneration? Spine (Phila Pa 1976). 2009; 34(2):189-192. 5. Bohl DD, Telles CJ, Hustedt JW, Blizzard DJ, Carlson EJ, Grauer JN. Post-anesthesia care unit imaging is unnecessary when intraoperative imaging is used during anterior cervical decompression and fusion procedures [published online ahead of print May 21, 2012]. J Spinal Disord Tech. doi: 10.1097/ BSD.0b013e31825d99f6 6. Ugokwe KT, Kalfas IH, Mroz TE, Steinmetz MP. A review of the utility of obtaining repeated postoperative radiographs following single-level anterior cervical decompression, fusion, and plate placement. J Neurosurg Spine. 2008; 9(2):175-179.
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