Is Reoperation Higher Than Expected after Below-the-knee Amputation? A Single-center Evaluation of Factors Associated with Reoperation at 1 Year.

BACKGROUND: Below-the-knee amputation (BKA) is relatively common among patients with vascular disease, infection, trauma, or neoplastic disease. Many BKAs are performed in patients with incompletely treated medical comorbidities, and some are performed in patients with acute high-energy trauma or crush injuries, malignant neoplasm undergoing time-sensitive limb removal, and diabetes with active infection or sepsis. Consequently, revision is common. Prior studies of outcomes after BKA, including several based on the American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) database, have follow-up periods that do not cover the entire at-risk period. QUESTIONS/PURPOSES: (1) What is the survivorship free from unplanned reoperation within 1 year of BKA? (2) What patient characteristics are associated with reoperation within 1 year of BKA? METHODS: We retrospectively studied all BKAs performed by the orthopaedic surgery service at a Level 1 trauma center from 2008 to 2018, as identified by Current Procedural Terminology (CPT) codes. Twenty-eight percent (38 of 138) underwent amputation as treatment for traumatic injury, 57% (79 of 138) for infection, and 15% (21 of 138) for malignancy. A total of 17% (23 of 138) had a final follow-up encounter before the 1-year study minimum, without differential loss to follow-up by surgical indication (p = 0.43) or hemoglobin A1c (p = 0.71). Median (range) follow-up was 570 days (6 to 3375). The primary outcome was survivorship from unplanned reoperation within 1 year of BKA index surgery or last planned reoperation, as determined by Kaplan-Meier estimation. Secondarily, we identified patient characteristics independently associated with reoperation within 1 year of BKA. Collected data included age, indication, BMI, diabetes, hemoglobin A1c level, closure method, and substance use. Unplanned reoperation was defined as irrigation and débridement, stump revision, or revision to a higher-level amputation; this did not include planned reoperations for BKAs closed in a staged manner. Factors associated with reoperation were determined using multivariate logistic regression analyses. All endpoints and variables related to patients and their surgical procedures were extracted from electronic medical records by someone other than the operating surgeon. RESULTS: Using Kaplan-Meier estimation, 38% of patients (95% confidence interval 29 to 46) who underwent BKA had an unplanned reoperation within 1 year of their index surgery. Twelve percent of patients (95% CI 7 to 17) who underwent BKA did not reach 30 days with the limb survivorship free from unplanned reoperation. The median (range) time between the initial surgery and reoperation was 54 days (6 to 315). After controlling for potential confounding variables like age, gender, platelet count, albumin, and the reason for undergoing amputation, a hemoglobin A1c level greater than 8.1% (relative to A1c ≤ 8.1%) was the only variable independently associated with increased odds of reoperation (odds ratio 4.6 [95% CI 1.3 to 18.1]; p = 0.02). CONCLUSION: BKA carries a higher risk for reoperation than currently reported in studies that use 30-day postoperative follow-up periods. Clinicians should critically assess whether BKA is necessary, especially in patients with uncontrolled diabetes assessed by hyperglycemia. Before planned BKA, patients should have documented glycemic control to minimize the odds of reoperation. Because many of this study's limitations were due to its retrospective single center design, we recommend that future work cover a clinically appropriate surveillance period using a larger cohort such as a national database and/or employ a prospective design. LEVEL OF EVIDENCE: Level III, therapeutic study.

Association between tourniquet use and intraoperative blood loss during below-knee amputation.

BACKGROUND: Despite over 150000 amputations of lower limbs annually, there remains a wide variation in tourniquet practice patterns and no consensus on their necessity, especially among orthopedic patient populations. The purpose of this study was to determine whether tourniquet use in orthopedic patients undergoing below knee amputation (BKA) was associated with a difference in calculated blood loss relative to no tourniquet use. AIM: To determine if tourniquet use in orthopedic patients undergoing BKA was associated with a difference in calculated blood loss relative to no tourniquet use. METHODS: We performed a retrospective review of consecutive patients undergoing BKA by orthopedic surgeons at a tertiary care hospital from 2008 through 2018. Blood loss was calculated using a combination of the Nadler equation for preoperative blood volume and a novel formula utilizing preoperative and postoperative hemoglobin levels and transfusions. Univariate and forwards step-wise multivariate linear regressions were performed to determine the association between tourniquet use and blood loss. A Wilcoxon was used to determine the univariate relationship between tourniquet use and blood loss for in the restricted subgroups of patients who underwent BKA for trauma, tumor, and infection. RESULTS: Of 97 eligible patients identified, 67 underwent surgery with a tourniquet and 30 did not. In multivariate regression, tourniquet use was associated with a 488 mL decrease in calculated blood loss (CI 119-857, P = 0.01). In subgroup analysis, no individual group showed a statistically significant decrease in blood loss with tourniquet use. There was no significant association between tourniquet use and either postoperative transfusions or reoperation at one year. CONCLUSION: We found that tourniquet use during BKA is associated with decreased calculated intraoperative blood loss. We recommend that surgeons performing this procedure use a tourniquet to minimize blood loss.

Effects of delayed postoperative void and preoperative urologic symptoms on delay in time of discharge for elective lumbar decompression surgery.

BACKGROUND CONTEXT: Almost half of all patients undergoing lumbar spine surgery have preoperative lower urinary tract symptoms (LUTS). These symptoms could affect postoperative voiding and subsequently length of stay. PURPOSE: To investigate the association between preoperative LUTS and time to first void and between time to first void and time to discharge among patients undergoing elective lumbar decompression surgery. STUDY DESIGN/SETTING: Retrospective analysis of prospectively collected data among patients at a single academic medical center. PATIENT SAMPLE: All patients ≥18 years of age undergoing elective lumbar decompression surgery between July 2017 and March 2020. OUTCOME MEASURES: The physiologic measure of a delayed time to first void was defined as an initial postoperative void of > 4 hours after anesthesia stop time. The outcome of prolonged time to discharge was defined as a stay of >24 hours after anesthesia stop time. METHODS: At their preoperative visit, patients completed the validated International Prostate Symptom Score (IPSS) (range, 0-35 points), which is applicable for LUTS assessment in both sexes. Clinically relevant LUTS are defined as an IPSS score of ≥8. Patients were followed from their preoperative visit to surgery admission discharge. Association of LUTS with time to first void and time to first void with admission discharge were estimated using risk ratios (RR) and 95% confidence intervals (CI) from a multivariable Poisson regression with a robust variance estimate adjusted for potential confounding variables including age, sex, IPSS, and intraoperative Foley catheter use. RESULTS: The analytic cohort included 170 patients with an average age of 57 years and 103 (61%) were men. Preoperative LUTS prevalence was 45%, and 111 (65%) of patients voided within 4 hours after surgery. For patients with preoperative LUTS, the unadjusted RR for a first void of >4 hours was 1.04 (95% CI: 0.82-1.32) (p=.77). Adjustment for age, sex, intraoperative Foley catheter use, revision surgery, previous spine surgery, single versus multiple levels, and lumbar location did not materially alter the risk: the multivariable RR was 1.04 (95% CI: 0.82-1.31) (p=.74). The unadjusted RR for a discharge of > 24 hours for patients with a time to first void of > 4 hours was 2.17 (95% CI: 1.51-3.10) (p<.001). After adjusting for age, sex, intraoperative Foley catheter use, IPSS, revision surgery, previous spine surgery, single versus multiple levels, and lumbar location, the multivariable RR was 1.72 (95% CI: 1.22-2.41) (p=.002). CONCLUSIONS: Regardless of preoperative LUTS status, an initial first void of >4 hours after surgery is associated with a longer time to discharge among patients undergoing elective lumbar decompression surgery. Future studies are needed to determine if encouraging early postoperative voiding results in timely discharge and shorter length of stay.