Is Postoperative Pain Different in the MICS CABG Cohort V. the Traditional Sternotomy Cohort Study?

Within the cardiothoracic surgical population postoperative
pain is a known phenomenon with varying levels of severity...


ISSN: 2574 -1241
Purpose: To determine whether a minimally invasive approach to coronary artery bypass surgery substantially impacts postoperative pain levels.
Background: Within the cardiothoracic surgical population postoperative pain is a known phenomenon with varying levels of severity, ranging from minimal to severe discomfort. Minimally invasive cardiac surgery (MICS) has been around since 1995, however there remain few studies that tackle the comparison of pain between this approach versus the "traditional" sternotomy approach. Our study attempts to further the knowledge surrounding MICS, and possibly improve upon the concept of postoperative pain in the cardiac surgical patient.

Methods:
To adequately assess postoperative pain in the coronary artery bypass surgical population a multicentered retrospective chart review was carried out; the study utilized a nonexperimental comparative descriptive study design. The retrospective review was conducted over a six-month time frame, proceeding from June 2017 through November 2017, at two hospitals within the same organization. The data collection process began in late December of 2017 and carried through until January of 2018. The assessment of postop pain was performed by using a standard 11-point numeric rating scale/likert scale on post extubation day one and the day of discharge.

Results:
Stratifying for a length of stay less than or equal to 6 days, the mean reported pain levels on post extubating day one and on the day of discharge were 8.3 and 3.9 for the sternotomy sample group, and 8.06 and 2.5 for the MICS group. The associated p-value for the day of discharge was 0.0196, which was determined to be statistically significant.
Conclusions: Our study found that MICS patients report a statistically significant lower pain on the day of discharge in comparison to the patients who undergo traditional sternotomy. frame, consisting from June 2017 through November 2017, at two hospitals within the same organization. One of the hospitals was a level one trauma center within the epicenter of a major southeastern metropolitan area, and the second was a community hospital within the suburbs of the same city's geographical limits. The data collection process began in late December of 2017 and concluded in January of 2018 [2]. The process included systematically analyzing the following medical record information for all patients: the preoperative history and physical note, preoperative consultation notes, the operative note, and lastly the postoperative pain assessment administered by the nursing staff post procedure. The postoperative pain assessment was performed using the standard 11-point numeric rating scale (Elfering and Haefeli, example in (Appendix).

Appendix A.
The highest reported/recorded pain level on the day post extubation, and the highest reported/recorded pain level on the day of discharge were chosen prior to commencement of the study (Table 1). Inclusion for participation in the retrospective review was limited to patients who had an isolated coronary artery bypass surgery, either minimally invasive or a "traditional" sternotomy, within the predetermined six-month time frame (Figure 1).
The exclusion criteria for the review consisted of the following: documented history of any chronic pain syndromes requiring active treatment, the "relative" recent requirement of narcotic analgesic use for pain relief prior to operation, any CABG operation that inadvertently resulted in an operative surgical complication, and patient cases that resulted in readmissions within 30 days from surgery. These inclusion and exclusion criteria were set prior to the data collection process. Of note, surgical complications that excluded patients included delayed sternal closure (4) and sternal wound infection (1). The other exclusion criteria resulted in a total 28 patients being omitted from the statistical testing for a total of 179 patients for analysis (Tables 2 & 3). After the conclusion of data collection multiple statistical tests were then performed to determine where there were any significant differences among the two sample groups [3,4].         The two sample populations were then stratified based upon length of stay, where those patients who were discharged after postoperative day 6 excluded, in order to remove unaccounted bias in the aforementioned results (please see detailed explanation of 6 day cut exclusion criteria in the discussion section). With a length of stay < or = to 6 days the MICS sample size had decreased to 31 and the traditional sternotomy sample size was now 70 patients [5,6]. This resulted in a median reported pain level of 3.97 in the traditional sternotomy sample group, and a median reported pain level of 2.58 in the MICS sample group. The Wilcoxon rank sum test (t-test equivalent) was then performed again with a returned a p-value of 0.0196. This result was determined to be statistically significant (Table 6) ( Figure 2).

Conclusion
Our study found that MICS patients report a statistically significant lower pain on the day of discharge in comparison to the patients who undergo traditional sternotomy. This is not to say that one operative technique is more superior than the other, especially given that certain patient characteristics must be met to justify a minimally invasive approach, however, our findings support a more serious consideration for minimally invasive cardiac surgery if deemed a viable option and should encourage further research on these two operative techniques