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Conventional versus digital radiographs for intraoperative cervical spine-level localization: a prospective time and cost analysis
The Spine Journal 9 (2009) 967–971
Clinical Study
Conventional versus digital radiographs for intraoperative cervical spine-level localization: a prospective time and cost analysis Michael P. Steinmetz, MDa,*, Thomas E. Mroz, MDa, Ajit Krishnaney, MDa, Michael Modic, MDb a
Center for Spine Health, Neurological Institute, Cleveland Clinic, 9500 Euclid Ave., S-80, Cleveland, OH 44195, USA b Neurological Institute, Cleveland Clinic, 9500 Euclid Ave., S-80, Cleveland, OH 44195, USA Received 29 September 2008; revised 27 June 2009; accepted 20 July 2009
Abstract
BACKGROUND: In today’s health-care environment, operational efficiency is intrinsic to balancing the need for increased productivity driven by rising costs and potentially decreasing reimbursement. Other operational factors kept constant, decreasing the time for a procedure can be viewed as one marker for increased efficiency. PURPOSE: To prospectively evaluate the time and operating room efficiency differences between the two methods for intraoperative level localization. STYDY DESIGN: Prospective nonrandomized study. PATIENT SAMPLE: Prospective consecutive patients undergoing a single-level anterior cervical discectomy and fusion (ACDF) with plate and allograft. OUTCOMES MEASURES: Time for performance and interpretation of intraoperative localization radiograph. METHODS: This is a prospective nonrandomized study of patients treated consecutively with a single-level ACDF with allograft and plating. All the patients underwent a conventional approach to the cervical spine. After exposure, a spinal needle was placed in the exposed intervertebral disc and a radiography was performed. Either a conventional or a digital radiography was used in each case. RESULTS: Eighteen patients were enrolled in this study. Ten patients underwent localization with conventional radiography, whereas eight patients underwent localization with digital imaging. The mean time for conventional radiography was 823 seconds (standard deviation [SD], 159), and for digital, it was 100 seconds (SD, 34; p!.001). CONCLUSIONS: Current technology provides options for level localization. Digital imaging provides equally accurate information as conventional radiography in a significantly reduced amount of time. Image quality, ease or archival, and manipulation provided by digital radiography are superior to those by provided fluoroscopy. Keeping operational factors constant, decreasing the time for a procedure, and increasing the efficiency of the environment may be viewed as a surrogate for improving the cost basis for a procedure. Ó 2009 Elsevier Inc. All rights reserved.
Keywords:
ACDF; Cervical; Fusion; Localization radiograph; Socioeconomics; Spine
Introduction In today’s health-care environment, operational efficiency is intrinsic to balancing the need for increased FDA device/drug status: not applicable. Author disclosures: MPS (speaking/teaching arrangements, Stryker Spine); TEM (stock ownership, PearlDiver, Inc.). * Corresponding author. Center for Spine Health, Cleveland Clinic, 9500 Euclid Ave., S-80, Cleveland, OH 44195, USA. Tel.: (216) 4454633; fax: (216) 636-5457. E-mail address: [email protected] (M.P. Steinmetz) 1529-9430/09/$ – see front matter Ó 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.spinee.2009.07.004
productivity driven by rising costs and potentially decreasing reimbursement. Other operational factors kept constant, decreasing the time for a procedure can be viewed as one marker for increased efficiency. With improved efficiency, the hospital is better able to serve more people and reinvest in medical infrastructure. A localization X-ray in spine surgery has become conventional of care. Surgery to remove pathology, such as a herniated disc, cannot be safely performed unless the surgeon confirms that he/she is at the correct level. Operating
968
M.P. Steinmetz et al. / The Spine Journal 9 (2009) 967–971
Context Decreasing intraoperative times might provide medical benefits and conserve value resources. This article assesses time needed to obtain and read conventional versus digital localization radiographs during ACDF. Contribution The authors’ institution found digital radiography to take less time than conventional films: less than two minutes compared with nearly 15, respectively. Implications Efforts to make operative time more efficient are to be applauded. Apparent system efficiencies must be weighed against costs, risks, and technical factors. Does the decreased time correlate with decreased overall expense? Is there a difference in radiation exposure, infection risks, etc? Are different personnel or skills needed to use the technologies? What happens when the radiology server goes down? These questions are unanswered in the current study. —The Editors at the wrong level does not relieve the patient’s symptoms, and it is one of the most common reasons for a patient to pursue a claim of malpractice [1]. The purpose of imaging is to 1) provide reliable anatomic or functional information and 2) provide information that will also affect therapeutic decision making. In the case of intraoperative information, a third factor becomes important. That is, to decrease the cycle time of the acquisition of this information that affects the decision-making process. While maintaining or increasing accuracy, decreasing the time will improve patient safety (less time under anesthesia [2]) and decrease potential surgeon frustration. Several options are available to localize a spinal level in the operating room (OR). One of the most common is a conventional lateral spine radiograph. This almost always permits localization but requires time for the technician to shoot the X-ray, develop the film, and bring it back to the OR for the surgeon to interpret. This, at times, requires a significant amount of time. In that interval, the surgeon is not operating but simply waiting for the radiograph to return before proceeding with the discectomy. Moreover, the patient is under general anesthesia without surgery moving forward. Some surgeons do, however, continue operating while waiting for the radiograph to return; this may further include soft-tissue dissection and exposure of the spine. This may be done in an attempt to maximize the downtime while waiting for the localization radiograph. Options to decrease the amount of time required include the use of fluoroscopy and digital radiography. Fluoroscopy permits real-time localization of the spinal level but is limited by
decreased resolution compared with conventional or digital radiography. There are significant issues related to image archival and storage with the use of fluoroscopy that are obviated by the use of digital imaging. The investigators hypothesize that conventional radiography requires more time for localization and adds unnecessary inefficiency for correct-level localization. Digital radiography and fluoroscopy, while requiring a higher initial investment for a hospital, permit less time for localization. Digital radiography provides better image quality, easier manipulation (eg, after processing), and archiving when compared with fluoroscopy. Due to the aforementioned shortcomings of fluoroscopy, this study compares localization with conventional versus digital radiography. The authors hypothesize that this will equate to increased efficiency and decrease time under anesthesia for the patient (safety).
Materials and methods This is a prospective nonrandomized study of a consecutive series of patients who underwent a single-level anterior cervical discectomy and fusion (ACDF) with allograft and plating. The operations were performed by three surgeons (MPS, AK, TEM) and were consecutive cases during a 3month period. A prestudy power analysis was performed and indicated the need for approximately five patients in each group. All the patients underwent a conventional approach to the cervical spine for the performance of ACDF (Smith Robinson technique). After exposure of the spine, a spinal needle was placed in the exposed intervertebral disc for localization. Then, a radiograph was performed with either conventional or digital radiography. The choice of X-ray modality was not predetermined and was chosen based on availability. The time was recorded for each modality in a specific manner. After placement of the localization needle into the spine, the technician began moving the equipment into the operative field for performance of the radiograph. This was marked as Time 0. This included the time to drape the X-ray cassette and position the X-ray beam. The X-ray technician then positioned the machine to perform the localization X-ray (cross-table lateral cervical radiograph). The radiograph was configured to the appropriate specifications as per the patient’s height and weight. Then, the technician brought the film copy of the cervical radiograph back to the surgeon for conventional interpretation or the surgeon read the radiograph on the screen on the machine for digital interpretation. After interpretation, the surgeon returned to the operative field, removed the needle, and resumed operating, and this was marked as Time 1. The time between 0 and 1 is the X-ray time. Statistics Because of small sample sizes and possible deviations from the normal distribution, a nonparametric method of
M.P. Steinmetz et al. / The Spine Journal 9 (2009) 967–971
analysis will be used. The Wilcoxon two-sample test with significance set to 5% (ie, a50.05) will be used to determine whether the digital radiography process is shorter in duration than the conventional radiography process.
Results Eighteen patients were enrolled in this study. Ten patients underwent localization with conventional radiography, whereas eight patients underwent localization using digital imaging. All the patients underwent single-level ACDF with allograft and plating (Table 1). Table 2 describes the average time for X-ray localization for each group. The mean time for conventional radiography was 823 seconds (standard deviation, 159), and for digital, it was 100 seconds (standard deviation, 34) (Figure). This difference was found to be statistically significant, using Wilcoxon two-sample test (S536 and p!.001).
Discussion To perform accurate and effective spine surgery, the surgeon must be confident that he/she is operating at the correct level. Operating at the wrong level is one of ‘‘the three sins’’ of lumbar microsurgery [3]. In the modern era, spine surgeons most often rely on a localization radiograph to determine the correct level. Failure to do so may result in operating on the wrong level. Operating on the wrong level is one of the most common causes of claims of malpractice [1]. This requires the surgeon to expose a portion of the spine and place a marker, such as a needle in the disc space or a clamp on a portion of the spine. A lateral radiograph is then performed. Then, the X-ray technician takes the X-ray Table 1 Patients underwent single-level anterior cervical discectomy and fusion with allograft and plating Gender F M F F F F M M M M F F M F M M F F
Age (y)
Level
Imaging modality
51 50 69 53 42 48 42 45 45 41 62 58 42 50 39 54 44 59
C6–C7 C5–C6 C5–C6 C4–C5 C5–C6 C5–C6 C5–C6 C6–C7 C6–C7 C4–C5 C4–C5 C5–C6 C6–C7 C6–C7 C5–C6 C5–C6 C5–C6 C6–C7
Digital Digital Digital Digital Digital Digital Digital Digital Standard Standard Standard Standard Standard Standard Standard Standard Standard Standard
F, female; M, male.
969
Table 2 Standard versus digital radiography for intraoperative localization in cases of single-level anterior cervical discectomy and fusion Variable n Mean (s) Median (s) Standard deviation (s) Skewness Kurtosis
Standard 10 823.0 780.0 158.76 1.0764 0.0237
Digital 8 99.6 113.5 34.12 0.8801 0.2715
cassette, develops and prints the film, and returns it to the operating room for the surgeon to determine what spinal level has been exposed. At times, this requires considerable time, upward of 20 to 30 minutes from the time of shooting the film until it is read by the surgeon. The cycle time of the acquisition of information is critical. While maintaining or even increasing accuracy, decreasing this time will improve patient safety and improve OR efficiency. Digital imaging decreases this cycle time of acquisition. The decompression or discectomy cannot move forward until the localization radiograph has been interpreted, but it should be stressed that some surgeons take advantage of the time while waiting and continue with certain portions of the operation, such as continued soft-tissue dissection or preparation of the soft-tissue retraction system. Any option that may reduce this cycle time will improve efficiency. One option is fluoroscopy. Fluoroscopy does provide real-time, rapid imaging of the spine, but it provides a different end product as compared with conventional or digital imaging. Although it might be adequate for localization, fluoroscopy has less spatial resolution as compared with digital and conventional radiographs, and there are significant logistical issues of image archival and ease of retrieval. Digital radiography provides a highresolution image equal to conventional radiography at a fraction of the time. The images may be manipulated in the operating room (after processing) and are easily stored and retrieved. Film-based imaging provides the same spatial resolution; however, the image cannot be manipulated, there is considerable time for film development, and lastly the films must be archived in film jackets stored on shelves. In the present study, the average time for level localization using conventional radiography was approximately 14 minutes, whereas it was approximately 2 minutes for digital imaging. This difference was found to be statistically significant. This difference in time reduces surgeon and surgical team frustration and total anesthesia time for the patient and may potentially increase the number of cases that may be performed in that operating room per day. Decreasing the time for a procedure, keeping other operational factors constant, may also be viewed as improving the cost basis for the procedure. The impact is much larger when one considers that localization is required in every case of spine surgery, and approximately 175,000 anterior cervical
970
M.P. Steinmetz et al. / The Spine Journal 9 (2009) 967–971
Figure. Histograms of conventional versus digital radiography processes. Comparing mean times, the (Top) conventional radiography process averaged 13:43 (13 min 43 s) and (Bottom) digital radiography process averaged 1:40.
surgeries are performed per year in the United States for disc diseases [4]. These data underscore potential impacts of improving efficiency. It is possible that decreasing the time under general anesthesia may lead to less intra- or perioperative morbidity for the patient. However, this study was not designed to assess this. The hospital may save money if decreasing ‘‘downtime’’ in the OR results in an increase in efficiency that could, for example, allow more cases to be done. Conversely, it may also lose money for the hospital if the time savings do not permit the latter and instead subtracts from billable OR time because of the higher efficiency. Finally, variables such as institution to institution billing paradigms and payer mix (private insurances, Medicare, self-pay) all need to be taken into account before an assessment of whether using digital imaging for level localization will result in cost savings
for the institution or for the patient. Our study was not designed to assess this, but we think it is a worthwhile endeavor to define. Charges and costs are affected by numerous factors and differ from institution to institution, but both time and efficiency improvements should translate into opportunities for all. A few shortcomings of this study are worthy of discussion. First is the study design. Although prospective, patients were enrolled in a nonrandomized format. Randomization may have had an effect on outcome, but the data acquisition times were similar in both groups, so this would not have likely had a huge impact. The second issue is sample size. Only 18 patients were enrolled in this study. A power analysis was performed before study design and revealed a need for only five patients in each group based on the assumption of a difference of approximately
M.P. Steinmetz et al. / The Spine Journal 9 (2009) 967–971
18 minutes between imaging modalities. Moreover, the differences between groups were large, and the times were similar within imaging groups. It is unlikely that the addition of more cases would have an impact on the significance of the data. The third issue would be the addition of fluoroscopy to the study design. The authors do believe that fluoroscopy would provide a rational, rapid means for image acquisition. The shortcomings of fluoroscopy (ie, bulky in the operative field, decreased spatial resolution, ease of hard copy storage, and archival) limit its use, and for this reason, it is not included in this study. Lastly, the study was not designed and did not assess true cost savings. We are unable then to demonstrate a decreased cost to the payers based on the data. The increased efficiency and decreased operating room time using digital radiographs did result in a decrease in OR charges, but that cannot be directly extrapolated into a cost savings. Although it is possible that decreased OR time could result in a cost savings, the study was not designed to show this. Other factors would have to be considered such as the capital investment required for the imaging modalities and their maintenance. The cost for performing each type of study (digital vs. conventional) may also differ. For the purposes of this study, the effectiveness was considered equal between modalities. This was based on the fact that no image had to be repeated because of inability to visualize the spinal level or inability to appropriate count to the index level. As physicians, we have an obligation to continuously strive to improve the quality and safety of the care of our patients. In the rapidly changing economic environment of health care, we are focused on decreasing cost. This
971
makes the implementation of new technology at times difficult. Critically evaluating our processes in an ongoing fashion in introducing technology where appropriate, occasionally results in situations where we can do both. This is such the case.
Conclusions Cervical spine intraoperative imaging is necessary for correct-level localization in anterior cervical surgery. Options, including conventional radiography and digital radiography, exist. Digital radiography provides a rapid and accurate technique for intraoperative localization and decreases the cycle time of acquisition of data. It does provide considerable time savings per case and should theoretically improve patient safety. This study emphasizes the need to embrace modern technology, critically evaluate our processes in an ongoing fashion, and improve our systems and efficiency. References [1] Fager CA. Malpractice issues in neurological surgery. Surg Neurol 2006;65:416–21. [2] Wimmer C, Gluch H. Management of postoperative wound infection in posterior spinal fusion with instrumentation. J Spinal Disord 1996;9:505–8. [3] McCulloch JA. Complications (adverse effects). In: McCulloch JA, ed. Principles of microsurgery for lumbar disc disease. New York, NY: Raven Press, 1989:225–38. [4] Merrill Lynch Incorporated. Spine industry report. New York, NY: Merrill Lynch Inc, 2001.
Clinical Study
Conventional versus digital radiographs for intraoperative cervical spine-level localization: a prospective time and cost analysis Michael P. Steinmetz, MDa,*, Thomas E. Mroz, MDa, Ajit Krishnaney, MDa, Michael Modic, MDb a
Center for Spine Health, Neurological Institute, Cleveland Clinic, 9500 Euclid Ave., S-80, Cleveland, OH 44195, USA b Neurological Institute, Cleveland Clinic, 9500 Euclid Ave., S-80, Cleveland, OH 44195, USA Received 29 September 2008; revised 27 June 2009; accepted 20 July 2009
Abstract
BACKGROUND: In today’s health-care environment, operational efficiency is intrinsic to balancing the need for increased productivity driven by rising costs and potentially decreasing reimbursement. Other operational factors kept constant, decreasing the time for a procedure can be viewed as one marker for increased efficiency. PURPOSE: To prospectively evaluate the time and operating room efficiency differences between the two methods for intraoperative level localization. STYDY DESIGN: Prospective nonrandomized study. PATIENT SAMPLE: Prospective consecutive patients undergoing a single-level anterior cervical discectomy and fusion (ACDF) with plate and allograft. OUTCOMES MEASURES: Time for performance and interpretation of intraoperative localization radiograph. METHODS: This is a prospective nonrandomized study of patients treated consecutively with a single-level ACDF with allograft and plating. All the patients underwent a conventional approach to the cervical spine. After exposure, a spinal needle was placed in the exposed intervertebral disc and a radiography was performed. Either a conventional or a digital radiography was used in each case. RESULTS: Eighteen patients were enrolled in this study. Ten patients underwent localization with conventional radiography, whereas eight patients underwent localization with digital imaging. The mean time for conventional radiography was 823 seconds (standard deviation [SD], 159), and for digital, it was 100 seconds (SD, 34; p!.001). CONCLUSIONS: Current technology provides options for level localization. Digital imaging provides equally accurate information as conventional radiography in a significantly reduced amount of time. Image quality, ease or archival, and manipulation provided by digital radiography are superior to those by provided fluoroscopy. Keeping operational factors constant, decreasing the time for a procedure, and increasing the efficiency of the environment may be viewed as a surrogate for improving the cost basis for a procedure. Ó 2009 Elsevier Inc. All rights reserved.
Keywords:
ACDF; Cervical; Fusion; Localization radiograph; Socioeconomics; Spine
Introduction In today’s health-care environment, operational efficiency is intrinsic to balancing the need for increased FDA device/drug status: not applicable. Author disclosures: MPS (speaking/teaching arrangements, Stryker Spine); TEM (stock ownership, PearlDiver, Inc.). * Corresponding author. Center for Spine Health, Cleveland Clinic, 9500 Euclid Ave., S-80, Cleveland, OH 44195, USA. Tel.: (216) 4454633; fax: (216) 636-5457. E-mail address: [email protected] (M.P. Steinmetz) 1529-9430/09/$ – see front matter Ó 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.spinee.2009.07.004
productivity driven by rising costs and potentially decreasing reimbursement. Other operational factors kept constant, decreasing the time for a procedure can be viewed as one marker for increased efficiency. With improved efficiency, the hospital is better able to serve more people and reinvest in medical infrastructure. A localization X-ray in spine surgery has become conventional of care. Surgery to remove pathology, such as a herniated disc, cannot be safely performed unless the surgeon confirms that he/she is at the correct level. Operating
968
M.P. Steinmetz et al. / The Spine Journal 9 (2009) 967–971
Context Decreasing intraoperative times might provide medical benefits and conserve value resources. This article assesses time needed to obtain and read conventional versus digital localization radiographs during ACDF. Contribution The authors’ institution found digital radiography to take less time than conventional films: less than two minutes compared with nearly 15, respectively. Implications Efforts to make operative time more efficient are to be applauded. Apparent system efficiencies must be weighed against costs, risks, and technical factors. Does the decreased time correlate with decreased overall expense? Is there a difference in radiation exposure, infection risks, etc? Are different personnel or skills needed to use the technologies? What happens when the radiology server goes down? These questions are unanswered in the current study. —The Editors at the wrong level does not relieve the patient’s symptoms, and it is one of the most common reasons for a patient to pursue a claim of malpractice [1]. The purpose of imaging is to 1) provide reliable anatomic or functional information and 2) provide information that will also affect therapeutic decision making. In the case of intraoperative information, a third factor becomes important. That is, to decrease the cycle time of the acquisition of this information that affects the decision-making process. While maintaining or increasing accuracy, decreasing the time will improve patient safety (less time under anesthesia [2]) and decrease potential surgeon frustration. Several options are available to localize a spinal level in the operating room (OR). One of the most common is a conventional lateral spine radiograph. This almost always permits localization but requires time for the technician to shoot the X-ray, develop the film, and bring it back to the OR for the surgeon to interpret. This, at times, requires a significant amount of time. In that interval, the surgeon is not operating but simply waiting for the radiograph to return before proceeding with the discectomy. Moreover, the patient is under general anesthesia without surgery moving forward. Some surgeons do, however, continue operating while waiting for the radiograph to return; this may further include soft-tissue dissection and exposure of the spine. This may be done in an attempt to maximize the downtime while waiting for the localization radiograph. Options to decrease the amount of time required include the use of fluoroscopy and digital radiography. Fluoroscopy permits real-time localization of the spinal level but is limited by
decreased resolution compared with conventional or digital radiography. There are significant issues related to image archival and storage with the use of fluoroscopy that are obviated by the use of digital imaging. The investigators hypothesize that conventional radiography requires more time for localization and adds unnecessary inefficiency for correct-level localization. Digital radiography and fluoroscopy, while requiring a higher initial investment for a hospital, permit less time for localization. Digital radiography provides better image quality, easier manipulation (eg, after processing), and archiving when compared with fluoroscopy. Due to the aforementioned shortcomings of fluoroscopy, this study compares localization with conventional versus digital radiography. The authors hypothesize that this will equate to increased efficiency and decrease time under anesthesia for the patient (safety).
Materials and methods This is a prospective nonrandomized study of a consecutive series of patients who underwent a single-level anterior cervical discectomy and fusion (ACDF) with allograft and plating. The operations were performed by three surgeons (MPS, AK, TEM) and were consecutive cases during a 3month period. A prestudy power analysis was performed and indicated the need for approximately five patients in each group. All the patients underwent a conventional approach to the cervical spine for the performance of ACDF (Smith Robinson technique). After exposure of the spine, a spinal needle was placed in the exposed intervertebral disc for localization. Then, a radiograph was performed with either conventional or digital radiography. The choice of X-ray modality was not predetermined and was chosen based on availability. The time was recorded for each modality in a specific manner. After placement of the localization needle into the spine, the technician began moving the equipment into the operative field for performance of the radiograph. This was marked as Time 0. This included the time to drape the X-ray cassette and position the X-ray beam. The X-ray technician then positioned the machine to perform the localization X-ray (cross-table lateral cervical radiograph). The radiograph was configured to the appropriate specifications as per the patient’s height and weight. Then, the technician brought the film copy of the cervical radiograph back to the surgeon for conventional interpretation or the surgeon read the radiograph on the screen on the machine for digital interpretation. After interpretation, the surgeon returned to the operative field, removed the needle, and resumed operating, and this was marked as Time 1. The time between 0 and 1 is the X-ray time. Statistics Because of small sample sizes and possible deviations from the normal distribution, a nonparametric method of
M.P. Steinmetz et al. / The Spine Journal 9 (2009) 967–971
analysis will be used. The Wilcoxon two-sample test with significance set to 5% (ie, a50.05) will be used to determine whether the digital radiography process is shorter in duration than the conventional radiography process.
Results Eighteen patients were enrolled in this study. Ten patients underwent localization with conventional radiography, whereas eight patients underwent localization using digital imaging. All the patients underwent single-level ACDF with allograft and plating (Table 1). Table 2 describes the average time for X-ray localization for each group. The mean time for conventional radiography was 823 seconds (standard deviation, 159), and for digital, it was 100 seconds (standard deviation, 34) (Figure). This difference was found to be statistically significant, using Wilcoxon two-sample test (S536 and p!.001).
Discussion To perform accurate and effective spine surgery, the surgeon must be confident that he/she is operating at the correct level. Operating at the wrong level is one of ‘‘the three sins’’ of lumbar microsurgery [3]. In the modern era, spine surgeons most often rely on a localization radiograph to determine the correct level. Failure to do so may result in operating on the wrong level. Operating on the wrong level is one of the most common causes of claims of malpractice [1]. This requires the surgeon to expose a portion of the spine and place a marker, such as a needle in the disc space or a clamp on a portion of the spine. A lateral radiograph is then performed. Then, the X-ray technician takes the X-ray Table 1 Patients underwent single-level anterior cervical discectomy and fusion with allograft and plating Gender F M F F F F M M M M F F M F M M F F
Age (y)
Level
Imaging modality
51 50 69 53 42 48 42 45 45 41 62 58 42 50 39 54 44 59
C6–C7 C5–C6 C5–C6 C4–C5 C5–C6 C5–C6 C5–C6 C6–C7 C6–C7 C4–C5 C4–C5 C5–C6 C6–C7 C6–C7 C5–C6 C5–C6 C5–C6 C6–C7
Digital Digital Digital Digital Digital Digital Digital Digital Standard Standard Standard Standard Standard Standard Standard Standard Standard Standard
F, female; M, male.
969
Table 2 Standard versus digital radiography for intraoperative localization in cases of single-level anterior cervical discectomy and fusion Variable n Mean (s) Median (s) Standard deviation (s) Skewness Kurtosis
Standard 10 823.0 780.0 158.76 1.0764 0.0237
Digital 8 99.6 113.5 34.12 0.8801 0.2715
cassette, develops and prints the film, and returns it to the operating room for the surgeon to determine what spinal level has been exposed. At times, this requires considerable time, upward of 20 to 30 minutes from the time of shooting the film until it is read by the surgeon. The cycle time of the acquisition of information is critical. While maintaining or even increasing accuracy, decreasing this time will improve patient safety and improve OR efficiency. Digital imaging decreases this cycle time of acquisition. The decompression or discectomy cannot move forward until the localization radiograph has been interpreted, but it should be stressed that some surgeons take advantage of the time while waiting and continue with certain portions of the operation, such as continued soft-tissue dissection or preparation of the soft-tissue retraction system. Any option that may reduce this cycle time will improve efficiency. One option is fluoroscopy. Fluoroscopy does provide real-time, rapid imaging of the spine, but it provides a different end product as compared with conventional or digital imaging. Although it might be adequate for localization, fluoroscopy has less spatial resolution as compared with digital and conventional radiographs, and there are significant logistical issues of image archival and ease of retrieval. Digital radiography provides a highresolution image equal to conventional radiography at a fraction of the time. The images may be manipulated in the operating room (after processing) and are easily stored and retrieved. Film-based imaging provides the same spatial resolution; however, the image cannot be manipulated, there is considerable time for film development, and lastly the films must be archived in film jackets stored on shelves. In the present study, the average time for level localization using conventional radiography was approximately 14 minutes, whereas it was approximately 2 minutes for digital imaging. This difference was found to be statistically significant. This difference in time reduces surgeon and surgical team frustration and total anesthesia time for the patient and may potentially increase the number of cases that may be performed in that operating room per day. Decreasing the time for a procedure, keeping other operational factors constant, may also be viewed as improving the cost basis for the procedure. The impact is much larger when one considers that localization is required in every case of spine surgery, and approximately 175,000 anterior cervical
970
M.P. Steinmetz et al. / The Spine Journal 9 (2009) 967–971
Figure. Histograms of conventional versus digital radiography processes. Comparing mean times, the (Top) conventional radiography process averaged 13:43 (13 min 43 s) and (Bottom) digital radiography process averaged 1:40.
surgeries are performed per year in the United States for disc diseases [4]. These data underscore potential impacts of improving efficiency. It is possible that decreasing the time under general anesthesia may lead to less intra- or perioperative morbidity for the patient. However, this study was not designed to assess this. The hospital may save money if decreasing ‘‘downtime’’ in the OR results in an increase in efficiency that could, for example, allow more cases to be done. Conversely, it may also lose money for the hospital if the time savings do not permit the latter and instead subtracts from billable OR time because of the higher efficiency. Finally, variables such as institution to institution billing paradigms and payer mix (private insurances, Medicare, self-pay) all need to be taken into account before an assessment of whether using digital imaging for level localization will result in cost savings
for the institution or for the patient. Our study was not designed to assess this, but we think it is a worthwhile endeavor to define. Charges and costs are affected by numerous factors and differ from institution to institution, but both time and efficiency improvements should translate into opportunities for all. A few shortcomings of this study are worthy of discussion. First is the study design. Although prospective, patients were enrolled in a nonrandomized format. Randomization may have had an effect on outcome, but the data acquisition times were similar in both groups, so this would not have likely had a huge impact. The second issue is sample size. Only 18 patients were enrolled in this study. A power analysis was performed before study design and revealed a need for only five patients in each group based on the assumption of a difference of approximately
M.P. Steinmetz et al. / The Spine Journal 9 (2009) 967–971
18 minutes between imaging modalities. Moreover, the differences between groups were large, and the times were similar within imaging groups. It is unlikely that the addition of more cases would have an impact on the significance of the data. The third issue would be the addition of fluoroscopy to the study design. The authors do believe that fluoroscopy would provide a rational, rapid means for image acquisition. The shortcomings of fluoroscopy (ie, bulky in the operative field, decreased spatial resolution, ease of hard copy storage, and archival) limit its use, and for this reason, it is not included in this study. Lastly, the study was not designed and did not assess true cost savings. We are unable then to demonstrate a decreased cost to the payers based on the data. The increased efficiency and decreased operating room time using digital radiographs did result in a decrease in OR charges, but that cannot be directly extrapolated into a cost savings. Although it is possible that decreased OR time could result in a cost savings, the study was not designed to show this. Other factors would have to be considered such as the capital investment required for the imaging modalities and their maintenance. The cost for performing each type of study (digital vs. conventional) may also differ. For the purposes of this study, the effectiveness was considered equal between modalities. This was based on the fact that no image had to be repeated because of inability to visualize the spinal level or inability to appropriate count to the index level. As physicians, we have an obligation to continuously strive to improve the quality and safety of the care of our patients. In the rapidly changing economic environment of health care, we are focused on decreasing cost. This
971
makes the implementation of new technology at times difficult. Critically evaluating our processes in an ongoing fashion in introducing technology where appropriate, occasionally results in situations where we can do both. This is such the case.
Conclusions Cervical spine intraoperative imaging is necessary for correct-level localization in anterior cervical surgery. Options, including conventional radiography and digital radiography, exist. Digital radiography provides a rapid and accurate technique for intraoperative localization and decreases the cycle time of acquisition of data. It does provide considerable time savings per case and should theoretically improve patient safety. This study emphasizes the need to embrace modern technology, critically evaluate our processes in an ongoing fashion, and improve our systems and efficiency. References [1] Fager CA. Malpractice issues in neurological surgery. Surg Neurol 2006;65:416–21. [2] Wimmer C, Gluch H. Management of postoperative wound infection in posterior spinal fusion with instrumentation. J Spinal Disord 1996;9:505–8. [3] McCulloch JA. Complications (adverse effects). In: McCulloch JA, ed. Principles of microsurgery for lumbar disc disease. New York, NY: Raven Press, 1989:225–38. [4] Merrill Lynch Incorporated. Spine industry report. New York, NY: Merrill Lynch Inc, 2001.