- Department of Neurological Surgery, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, USA
Brian P. Walcott
Department of Neurological Surgery, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, USA
DOI:10.4103/2152-7806.76144Copyright: © 2011 Walcott BP This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
How to cite this article: Walcott BP, Hanak BW, Caracci JR, Redjal N, Nahed BV, Kahle KT, Coumans JC. Trends in inpatient setting laminectomy for excision of herniated intervertebral disc: Population-based estimates from the US nationwide inpatient sample. Surg Neurol Int 24-Jan-2011;2:7
How to cite this URL: Walcott BP, Hanak BW, Caracci JR, Redjal N, Nahed BV, Kahle KT, Coumans JC. Trends in inpatient setting laminectomy for excision of herniated intervertebral disc: Population-based estimates from the US nationwide inpatient sample. Surg Neurol Int 24-Jan-2011;2:7. Available from: http://sni.wpengine.com/surgicalint_articles/trends-in-inpatient-setting-laminectomy-for-excision-of-herniated-intervertebral-disc-population-based-estimates-from-the-us-nationwide-inpatient-sample/
Background:Herniated intervertebral discs can result in pain and neurological compromise. Treatment for this condition is categorized as surgical or non-surgical. We sought to identify trends in inpatient surgical management of herniated intervertebral discs using a national database.
Methods:Patient discharges identified with a principal procedure relating to laminectomy for excision of herniated intervertebral disc were selected from the Nationwide Inpatient Sample (Healthcare Cost and Utilization Project - Agency for Healthcare Research and Quality, Rockville, MD), under the auspices of a data user agreement. These surgical patients did not undergo instrumented fusion. To account for the Nationwide Inpatient Sample weighting schema, design-adjusted analyses were used. The estimates of standard errors were calculated using SUDAAN software (Research Triangle International, NC, USA). This software is based on the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM); a uniform and standardized coding system.
Results:Using International Classification of Disease 9th Revision clinical modifier (ICD-9 CM) procedure code 80.51, we were able to identify disc excision, in part or whole, by laminotomy or hemilaminectomy. The incidence of laminectomy for the excision of herniated intervertebral disc has decreased dramatically from 1993 where 266,152 cases were reported [CI = 22,342]. In 2007, only 123,398 cases were identified [CI = 12,438]. The average length of stay in 1993 was 4 days [CI = 0.17], and in 2007 it decreased to just 2 days [CI = 0.17]. Both these comparisons were significantly different at P
Conclusions:National estimates indicate that the incidence of inpatient laminectomy for the excision of herniated intervertebral disc has decreased significantly. This trend is multifactorial and is likely related to developments in outcomes research, the growing popularity of alternative procedures (intervertebral instrumented fusion), and transition to an ambulatory setting of surgical care.
Keywords: Clinical Trials as Topic, diskectomy, intervertebral disk, magnetic resonance imaging, spinal fusion, spondylosis
We hypothesize that the incidence of laminectomy for intervertebral disc herniation in the inpatient setting has decreased over recent years. We also hypothesize that the length of inpatient stay for this procedure has decreased, although it has been associated with an increased cost. A complex clinical milieu influenced by ambulatory setting surgery, results of outcomes research, and alternative procedures may be responsible for trends observed.
We studied the practice patterns relating to the surgical treatment of herniated lumbar intervertebral discs from 1993 to 2007, which we obtained from the Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality (AHRQ) Rockville, MD.[
While the ICD-9 CM code for laminectomy for excision of intervertebral disc in description captures all disc herniations treated by laminectomy in the entire spine, it likely reflects mainly lumbar disc herniations. The lumbar region is the most common location of intervertebral disc herniation. Furthermore, laminectomies are less commonly performed for the treatment of cervical intervertebral herniated discs. Therefore, analysis of this ICD-9 CM code inherently self-selects to describe mainly those trends that are found in the lumbar region.
In addition, other inpatient statistics thought to be related to herniated intervertebral disc disease, (such as spinal fusion procedures [Clinical Classifications Software for ICD-9-CM category 158]), were queried.
To account for the Nationwide Inpatient Sample weighting schema, design-adjusted analyses were used. The estimates of standard errors were calculated using SUDAAN software (Research Triangle International, NC, USA). A Z-test was then used to determine the significance of the yearly incidence changes over the study period.
Hospital charges for the two types of surgical procedures were calculated based on hospital accounting reports from the Centers for Medicare and Medicaid Services. Adjustments for inflation were then calculated using the United States Bureau of Labor Statistics - The Consumer Price Index inflation calculator.[
The incidence of laminectomy for the excision of herniated intervertebral disc decreased dramatically from a starting point of 266,152 cases in 1993 SE = 11,399; 95% CI = 22,342. In 2007, there were only 123,398 cases reported SE = 6,346; 95% CI = 12,438; z statistic = 10.94, SE = 13,046.41, P (two tailed) = 0.000. [
The charges associated with a laminectomy for the excision of herniated intervertebral disc in 1993 averaged 10,308 USD [SE= 326; CI 550.94]. This value rose in 2007 to 24,639 USD [SE = 879; CI = 1485.51]; z statistic = 15.29, SE = 937.51, P (two tailed) = 0.000. This comparison was significant at P < 0.001. To adjust for inflation, the 1993 charges were manipulated to reflect buying power in the year 2007. This brought the average charge of the procedure in 1993 to 14,790.87 USD [SE= 467.78; CI = 916.85], z statistic 9.90, SE = 995.72, P (two tailed) = 0.000. The differences in inflation adjusted comparison remained significant at P < 0.001.
The incidence of spinal fusion procedures (HCUP Clinical Classifications Software category 158) increased dramatically from a starting point of 60,973 cases in 1993 [SE =5,108; 95% CI =10,011.68]. to 350,754 cases reported in 2007 SE =18,068; 95% CI = 35,413.28]; z statistic = 15.43, SE = 18,776.16, P (two tailed) = 0.000. [
The charges associated with a spinal fusion in 1993 averaged 24,045 USD [SE= 1,406; CI 2376.14]. This value rose in 2007 to 74,672 USD [SE = 2,069; CI = 3496.61]; z statistic = 20.24, SE = 2,501.52, P (two tailed) = 0.000. This comparison was significant at P < 0.001. To adjust for inflation, the 1993 charges were manipulated to reflect buying power in the year 2007. This brought the average charge of the procedure to 34,502 USD SE= 2017.46; CI = 3,954.22, z statistic 13.90, SE = 2,889.79, P (two tailed) = 0.000. The differences in inflation adjusted comparison remained significant at P < 0.001.
We studied a population of patients undergoing inpatient, non-instrumented surgical treatment of herniated intervertebral discs using a nationally representative hospital discharge database. The results of our analysis showed that the incidence laminectomy (performed as a principal procedure) has dramatically decreased during the study period from 1993 to 2007.
Surgery has long been viewed as the definitive treatment for symptomatic intervertebral disc herniation since the condition as first described by Mixter and Barr as a surgical disease.[
Recent comparisons of conservative management strategies to operative interventions for intervertebral disc herniation have helped to elucidate the natural history for mild to moderate disc herniations. The degree to which this has affected the rate of laminectomy for intervertebral disc is debatable. In the cervical spine, two prospective trials followed 48 and 68 patients with mild to moderate cervical spondylotic myelopathy for 2 and 3 years, respectively. After randomization to either conservative therapy or surgery, it was found that no significant differences between the two groups existed in terms of objective measures of functional status and self-perceived sense of clinical status.[
In addition to cervical disc herniation, studies have also been performed that assess the utility of operative intervention in the case of thoracic disc herniation.[
While initial reflection of the current literature generally suggests an expanding body of evidence in support for the effectiveness of conservative management in alleviating the symptoms of many herniated intervertebral discs, the overall incidence of procedures performed for the same has markedly increased. How then, does this relate to a decreasing rate of inpatient laminectomy for herniated intervertebral discs? We suspect the cause to be the rising rates of ambulatory setting surgery and spinal fusion to be implicated in generating the decreased incidence of inpatient laminectomy. For example, the proportions of discectomies performed on outpatients rose from 4% in 1994 to 26% in 2000.[
Limitations of this analysis reflect inherent deficiencies of a nationwide, code-based database. The database does not account for timing of the procedure, severity of disc herniation, or the identification of unique situations such as “traumatic disc.” There is no record of the degree of neurological impairment (if any) or the number or location of intervertebral levels involved. Re-operation rate is not accounted for in the database. Coding practices themselves may not reflect a completely accurate assessment of patient care rendered.
There is a growing body of evidence which suggests that surgical excision of herniated intervertebral disc is beneficial in a select group of patients. For many patients, non-operative management has proven an equivalent treatment option. Estimates from the Nationwide Inpatient Sample indicate that surgical procedures coded most specific to the inpatient surgical (non-instrumented) treatment of herniated intervertebral disc disease have significantly decreased. Increases in ambulatory surgery and spinal fusion have been documented and are likely implicated in the decreasing incidence of inpatient laminectomy for herniated intervertebral disc.
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