Smoking Linked to Greater Blood Loss and Need for Transfusions in Spinal Surgery
Commentary by Pete McCunniff, MD and Brandon B. Carlson, MD, MPH
Smoking is significantly associated with increased surgical blood loss and perioperative transfusions among patients undergoing lumbar spine surgery, according to a retrospective study in the April issue of Clinical Orthopaedics and Related Research.
“Smoking has been associated with an increased incidence of wound healing complications in all surgical areas,” explained lead author Pete McCunniff, MD, Orthopaedic Surgery Resident, University Hospitals-Case Medical Center, Cleveland, OH.
“In spinal surgery, the increased risk of pseudoarthrosis (surgical nonunion) after spinal fusion in smokers has been well documented for almost 30 years now. However, there is minimal data out there that has attempted to find any link smoking may have on surgical blood loss and transfusion use,” Dr. McCunniff told SpineUniverse. “Spinal surgeries are already highly associated with large volumes of blood loss and perioperative transfusion use; our research showed a significant association between smoking and estimated blood loss, as well as perioperative transfusion use. The increased blood loss makes for a more difficult surgery and transfusion usage comes with its own host of associated risks, including infection and wound complications, along with longer hospital stays and increased costs.”
Study Design and Key Findings
The study involved 537 patients who underwent lumbar decompression procedures (with or without fusion) performed at a single academic spine center. Of this group, 317 were nonsmokers and 220 were smokers.
In multivariate analysis, smokers had a significantly increased estimated blood loss during surgery compared with nonsmokers (mean, 328 mL more for each pack per day smoked; P<0.001). In addition, smokers had an increased risk for perioperative transfusions for each pack per day smoked (odds ratio, 13.8). The analyses controlled for age, sex, number of levels of discectomies, and number of levels instrumented.
Mechanisms Underlying the Link Between Smoking and Blood Loss in Surgery
When asked about the possible mechanisms that may underlie the increased risk for blood loss during spinal surgery among smokers, Dr. McCunniff said that this is “definitely one of the areas where more research is needed.”
“There are some promising studies examining the effects that smoking has on the clotting cascade at the cellular level,” Dr. McCunniff explained. “It has been shown to affect the cytoskeleton of platelets changing their membrane properties and compromising their ability to function properly. It also has been shown that the red blood cells themselves undergo changes in their membranes causing them to exhibit increased fragility and hemolysis, which could contribute to anemia in the perioperative setting.”
Implications of the Negative Effects of Smoking on Surgery Outcomes
“I believe this is just yet another negative effect that cigarette smoking has on the body,” Dr. McCunniff said. “Our research findings have changed the way that we counsel patients before undergoing elective lumbar surgery, and we attempt to impress on them the negative effects of increased bleeding during the perioperative period, and the marked increased risk of transfusions if they are unable to quit smoking before surgery. In smokers who are going to undergo a large lumbar decompression procedure, it may be pertinent to attempt to use blood conservation techniques such as cell-savers or tranexamic acid.”
“If a patient is a smoker, counseling them on quitting during the perioperative period can be extremely beneficial for the patient and for the surgical outcomes,” Dr. McCunniff said. “Although we do not have research detailing how long the effects of smoking last in platelets and red blood cells, we do know from past studies that 4 to 8 weeks of smoking cessation before surgery resulted in reductions of postoperative morbidity in patients undergoing elective surgery. Hopefully, this can be used at motivation by patients to help them begin the process of quitting for good.”
“McCunniff et al’s findings add to the current literature supporting increased risks and complications in smokers undergoing spine surgery,” commented Brandon B. Carlson, MD, MPH, who is a resident in the Department of Orthopedic Surgery, University of Kansas Medical Center in Kansas City, KS. “Increased blood loss and postoperative transfusions are significant surgical risks. Surgeons should recognize these risks, educate their patients, and employ preoperative smoking cessation protocols to optimize surgical outcomes and positively impact the patients’ overall health.”
Dr. Carlson and colleagues recently published findings from a prospective study showing that while some patients are able to stop smoking before spinal surgery, the majority of patients resume smoking within the first 3 months postoperatively.
Patients May Be Willing to Stop Smoking Temporarily Before Surgery
“Preoperative smoking cessation prior to elective spine surgery is a unique opportunity to intervene and reduce the health burden of tobacco use,” Dr. Carlson said. “Our institution’s protocol is for tobacco users undergoing elective spinal fusion surgery to be nicotine-free for minimum 30 days prior to surgery. We found that most patients are willing to quit smoking prior to elective spinal surgery. We confirmed patients’ smoking status with a nicotine/cotinine blood test prior to scheduling surgery. We did not study what cessation methods were used preoperatively; however, this clinically important topic should be investigated in the future.”
“In our study, we had 100% compliance among patients willing to participate in our preoperative protocol,” Dr. Carlson said. “Despite this, we found a 60% relapse rate within the first 3 months postoperatively. Our ongoing studies will determine if postoperative smoking cessation maintenance interventions will lower the relapse rate and whether this impacts clinical and surgical outcomes.”