The Spine Blog

Friday, August 8, 2014

How costly is an incidental durotomy?

Incidental durotomy is a common complication in lumbar spine surgery and can be seen in cervical spine surgery as well. It has been studied extensively, though questions still remain about the best way to manage dural tears. Given that durotomy is a common complication that is treated with a period of bedrest, it is well known that it increases length of stay and costs to the healthcare system. As such, Dr. Singh and his colleagues from Chicago performed a cost analysis using the National Inpatient Sample (NIS) database to compare costs, length of stay, and complications associated with incidental durotomy in cervical and lumbar spine surgery. They analyzed over 275,000 cases captured in the database and reported a durotomy rate of 0.4% for cervical surgery and 2.9% for lumbar surgery. After controlling for demographic characteristics, comorbidity burden, and hospital factors, they determined that incidental durotomy increased hospital costs by $7,638 for cervical surgery and $2,412 for lumbar surgery. Durotomy increased length of stay by 1.8 days after cervical surgery and 1.3 days after lumbar surgery. The authors also reported increased rates of other complications following durotomy including hematoma, neurological injury, DVT, PE, ileus, and UTI.


The results of this study come as no surprise, but the question that emerges is how much the durotomy actually contributes to the observed differences. In this study and prior studies on the topic, durotomies were more likely to occur in patients undergoing more extensive, more complex surgery, and these patients were older with a greater comorbidity burden. While the authors attempted to control for some of these factors in their analysis, the number of covariates that can be gleaned from billing data is quite limited, and there are clearly many unmeasured confounders that are likely contributing to the reported differences in addition to the incidental durotomy. Another major limitation in studying complications in the NIS database is that they are frequently not recorded in the billing data, and this is reflected in the very low rates of incidental durotomy in this study. The lumbar decompression group has a durotomy rate of 3.5%, markedly lower than the 9% reported in the SPORT spinal stenosis study. It is highly likely that many of the durotomies were not coded, which limits the conclusions that can be drawn from the study. Similarly, while bedrest following durotomy could increase the rates of complications such as DVT, PE, and UTI, it is also possible that hospitals that more frequently code durotomy also code other complications more frequently. This study serves as a reminder that durotomy is not a completely benign complication and increases costs to the healthcare system. Given that durotomies are a part of spine surgery that cannot be eliminated, future efforts should focus on the most cost-effective way to treat them. Studies should determine if the use of patches and sealant is cost-effective and if using such technology can decrease the need for bedrest. There is wide variation in how incidental durotomies are treated, and a high quality multicenter study evaluating different approaches might allow for the development of a widely-accepted protocol that is both safe and cost-effective.


Please read Dr. Singh’s article on this topic in the August 1 issue. Does this article change how you view incidental durotomies? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor