Cross-sectional area of the abdomen predicts complication incidence in patients undergoing sternal reconstruction

Comparison of abdominal adipose tissue versus body mass index (BMI) as a predictor of complications and survival in liver transplantation

INTRODUCTION

Because of the obesity epidemic, more obese patients are on liver transplant (LT) waiting lists. The diseases associated with obesity may increase complications and limit survival after LT. However, there is no established measure or cut-off point to determine this impact and aid decision making. The aim of the present study is to evaluate obesity in patients undergoing LT via BMI and CT-based measurement of adipose tissue (AAT). These parameters will be used to predict the risk of postoperative complications and 5-year survival.

METHODS

A retrospective, single-center study was carried out at a tertiary Spanish hospital, including all patients who received LT between January 2012 and July 2019 (n = 164). The patients were adults who underwent LT using the 'piggyback' technique, preserving the recipient vena cava. Visceral adipose tissue (VAT) and BMI were calculated to examine correlations with postoperative complications and 5-year survival.

RESULTS

No significant association was found between postoperative complications by Comprehensive Complication Index, BMI, AAT/height, subcutaneous fat/height and VAT/height. Kaplan-Meier curves for 5-year survival compared LT recipients with BMI < 30.45 versus ≥30.45, with an estimated survival of 58.97 months versus 43.11 months, respectively (P < .001) (Fig. 3) and for LT recipients with an AAT/height <27.35 mm versus ≥27.35 mm, with an estimated survival of 57.69 months versus 46.34 months (P = .001).

CONCLUSIONS

This study does not show a higher rate of postoperative complications in obese patients. There is a significantly lower long-term survival in patients with AAT/height ≥27.35 mm and BMI ≥ 30.45. BMI is a valid estimate of obesity and is predictive of survival.

A Radiographic Abdominal Pannus Sign is Associated With Postoperative Complications in Anterior THA

BACKGROUND

Numerous studies have shown that elevated BMI is associated with adverse outcomes in THA; however, BMI alone does not adequately represent a patient's adipose and soft tissue distribution, especially when the direct-anterior approach is evaluated. Local soft tissue and adipose, especially in the peri-incisional region, has an unknown impact on patient outcomes after direct-anterior THA. Moreover, there is currently no known evaluation method to estimate the quantity of local soft tissue and adipose tissue. The current study introduced a new radiographic parameter that is measurable on supine AP radiographs: the abdominal pannus sign.

QUESTION/PURPOSE

Are patients who have an abdominal pannus extending below the upper (cephalad) border of the symphysis pubis more likely to experience problems after anterior-approach THA that are plausibly associated with that finding, including infections resulting in readmission, wound complications resulting in readmission, fractures, or longer surgical time, than patients who do not demonstrate this radiographic sign?

METHODS

Between 2015 and 2020, five surgeons performed 727 primary direct-anterior THAs. After exclusion criteria were applied, 596 procedures were included. Of those, we obtained postoperative radiographs in the postanesthesia care unit in 100% of procedures (596 of 596), and 100% of radiographs (596) were adequate for review in this retrospective study. The level of the pannus in relation to the pubic symphysis was assessed on immediate supine postoperative AP radiographs of the pelvis: above (pannus sign 1), between the upper and lower borders (pannus sign 2), or below the level of the pubic symphysis (pannus sign 3). In this study, we combined pannus signs 2 and 3 into a single group for analysis not only because there was a limited number of patients in each group, but also because there was no statistically significant difference between the two groups. Pannus sign 1 was identified in 82% of procedures (486 of 596), and pannus sign ≥ 2 was identified in 18% (110). We compared the groups (pannus sign 1 versus pannus sign ≥ 2) in terms of the percentage of patients who experienced problems within 90 days of THA that might be associated with that physical finding, including infections resulting in readmission including subcutaneous, subfascial, and prosthetic joint infections; wound complications resulting in readmission, defined as dehiscence or delayed healing; and all fractures, and we compared the groups in terms of surgical time-that is, the cut-to-close time.

RESULTS

Patients with a pannus sign of ≥ 2 were more likely than those with a pannus sign of 1 to have a postoperative infection (6.4% [seven of 110 procedures] versus 0.6% [three of 486], odds ratio 10.96 [95% confidence interval (CI) 2.83 to 42.38]; p < 0.01), wound complications (0.9% [one of 110] versus 0% [0 of 486] with an infinite odds ratio [95% CI indeterminate]; p = 0.18), and fractures (4.5% [five of 110] versus 0% [0 of 486], with an infinite odds ratio [95% CI indeterminate]; p < 0.01). The mean surgical time was longer in patients with a pannus sign of ≥ 2 than it was in those with a pannus sign of 1 (128 ± 25.3 minutes versus 118 ± 27.5 minutes, mean difference 10 minutes; p < 0.01).

CONCLUSION

Based on these findings, patients who have an abdominal pannus that extends below the upper (cephalad) edge of the pubic symphysis are at an increased risk of experiencing serious surgical complications. If THA is planned in these patients, an approach other than the direct-anterior approach should be considered. Surgeons performing THA who do not obtain supine radiographs preoperatively should use a physical examination to evaluate for this finding, and if it is present, they should use an approach other than the direct-anterior approach to minimize the risk of these complications. Future studies might compare the abdominal pannus sign using standing radiographs, which are used more often, with other well-documented associated risk factors such as elevated BMI or higher American Society of Anesthesiologists classification.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

The use of local adiposity as a proxy for obesity in primary total hip arthroplasty: A systematic review

Introduction

Preoperative optimization of obese patients is a critical component of risk stratification in primary total hip arthroplasty (THA). Body mass index is ubiquitously utilized as a proxy for obesity due to its ease of attainment and simplistic interpretation. The use of adiposity as a proxy for obesity is an emerging concept. Local adiposity provides insight into the magnitude of peri-incisional tissue and has demonstrated an association with postoperative complications. Our objective was to review the literature to determine if local adiposity is a reliable predictor for complications following primary total hip arthroplasty.

Methods

In keeping with the PRISMA guidelines, a database search of PubMed was conducted for articles which reported on the relationship between quantified measures of adiposity at the hip and rates of complication following primary THA. Methodological quality was assessed using GRADE and risk of bias using ROBINS-I.

Results

A total of six articles (N = 2931) met the inclusion criteria. Local adiposity at the hip was measured on anteroposterior radiograph in four articles and was measured intraoperatively in two. Across four of the six articles, adiposity was significantly associated with postoperative complications including prosthesis failure and infection.

Conclusion

The use of BMI as a predictor for postoperative complication has been fraught with inconsistency. There is momentum for adiposity to be used as a proxy for obesity in preoperative THA risk stratification. The current findings demonstrated that local adiposity may be a reliable predictor for complications following primary THA.

The Association Between Metabolic Derangement and Wound Complications in Elective Plastic Surgery

INTRODUCTION

The incidence of metabolically unhealthy obesity is rising nationally. In this study, we compare wound and overall complications between metabolically unhealthy obese and healthy patients undergoing elective plastic surgery and model how operative time influences a complication risk.

METHODS

Patients undergoing elective breast and body plastic surgery procedures in the 2009-2019 National Surgical Quality Improvement Program (NSQIP) dataset were identified. Complications were compared between metabolically unhealthy obese (body mass index [BMI] > 30 with diabetes and/or hypertension) versus metabolically healthy obese patients (BMI > 30 without diabetes or hypertension). Logistic regression was used to model the probability of wound complications across operative times stratified by metabolic status.

RESULTS

Of 139,352 patients, 13.4% (n = 18,663) had metabolically unhealthy obesity and 23.8% (n = 33,135) had metabolically healthy obesity. Compared to metabolically healthy patients, metabolically unhealthy patients had higher incidence of wound complications (6.9% versus 5.6%; P < 0.001) and adverse events (12.4% versus 9.6%; P < 0.001), in addition to higher 30-d readmission, returns to the operating room, and length of stay (all P < 0.001). After adjustment, BMI (Odds ratio [OR] 7.86), hypertension (OR 1.15), and diabetes (OR 1.25) were independent risk factors for wound complications (all P < 0.001). Among metabolically unhealthy patients, the operative time was log-linear with a wound complication risk (OR 1.21; P < 0.001).

CONCLUSIONS

Diabetes and hypertension are additive risk factors with obesity for wound complications in elective plastic surgery. Among patients with metabolically unhealthy obesity, a risk of wound complications increases logarithmically with operative time. This distinction with regard to metabolic state might explain the unclear impact of obesity on surgical outcomes within existing surgical literature.

Thickness of the Subcutaneous Fat as a Risk Factor for Surgical Site Infection Following Fragility Hip Fracture Surgery

INTRODUCTION

Surgical site infection (SSI) following fragility hip fracture (FHF) surgery is associated with increased morbidity and mortality.

SIGNIFICANCE

Prediction of patients at risk for SSI is fundamental. We aimed to determine whether subcutaneous radiographic fat measurement (SRM) is associated with increased SSI risk.

METHODS

A retrospective case-control comparison of SRMs at 3 locations around the hip. Patients diagnosed with SSI in the first post-operative year were matched with age, gender, surgical year, Charlsons' co-morbidity index score, and surgical type controls, not diagnosed with SSI, at a 1:2 ratio. Measurements included the distance between (1) the sourcil to skin surface (SS), (2) the tip of the greater trochanter to skin surface (TGTS), and (3) the most prominent lateral aspect of the greater trochanter to skin surface.

RESULTS

1430 patients were operated during the study period, of whom 45 patients presented with a diagnosis of SSI and compared to 90 controls. Infections occurred 27.4 ( ± 24.8) days following surgery. SRM significantly differed between groups, and all were higher in the study group; SS, 86.8 ± 25.5 cm vs 74.2 ± 15.3 cm; TGTS, 59.8 ± 26.3 cm vs 47.0 ± 15.8 cm; and LGTS, 45.4 ± 25.1 cm vs 33.2 ± 15.1 cm (P = .003, .004, and .004, respectively). Intraclass correlation coefficients (intra-rater) were high for all measurements (.999 for all). Intraclass correlation coefficients (inter-rater) for SS, TGTS and LGTS were high, .749 (.663.815), .792 (.719.847) and .817 (.751.866), respectively.

CONCLUSIONS

SRMs were found to be a valid and reproducible tool for predicting high risk of SSI in geriatric patients sustaining FHFs.

LEVEL OF EVIDENCE

III.

Novel radiographic hip fat thickness ratio correlates with early re-operation following total hip arthroplasty

INTRODUCTION

Obesity is thought to lead to increased failure rates following total hip arthroplasty (THA). Site-specific fat distribution has been suggested to be a better indicator of risk, compared to body mass index. Fat thickness measurement methods were developed for total knee arthroplasty, however, there is limited data on the methods for THA. The aim of this study was to assess the interobserver and intraobserver reliability of a newly defined radiographic subcutaneous fat thickness ratio and investigate the correlation of this ratio with early failure following THA.

METHODS

321 patients who underwent primary THA at a single institution between 2014 and 2017, with at least 1-year of follow-up and a preoperative pelvis anteroposterior x-ray radiograph were included in this study. A high hip fat thickness ratio (HFTR) was arbitrarily defined as ⩾2. Early failure was defined as revision or re-operation for any reason and death related to operation first year following THA.

RESULTS

The HFTR was shown to have excellent intraobserver and interobserver reliability. High HFTR was associated with higher risk of early failure following THA (odds ratio 3.8, [95% confidence interval, 1.2-12.1], p < 0.05). The same association persisted when HFTR was analysed as a continuous variable (p < 0.01) and in multivariate analysis (p < 0.05).

CONCLUSIONS

HFTR can be used to assess periarticular soft tissue distribution and may be regarded as a useful and reproducible tool for assessing risk of early failure following THA.

Soft-tissue thickness radiographic measurement: a marker to evaluate acute periprosthetic joint infection risk in total hip replacement

The objective of our study was to evaluate the association between acute periprosthetic joint infection (APJI) and radiographic measurement of soft-tissue thickness in elective total hip replacement surgery. A case-control study was conducted to compare the soft-tissue thickness radiographic measurement (SRM) at the hip in patients diagnosed with APJI based on Tsukayama et al. (2003) criteria after total hip replacement with patients that were not infected, at a single institution from 2013 to 2019. To minimize selection bias, each case was matched with two controls using the following methodology: patients of the same sex, with an age variation of ± 5 years, and nearest in surgery date to the cases were selected. All postoperative radiographs were performed in the first 24 h after total hip arthroplasty (THA) surgery as it is protocolized in our institution. Soft-tissue thickness radiographic measurement was defined as the distance from the tip of the greater trochanter to the skin following a perpendicular line to the femoral diaphysis in postoperative anteroposterior hip radiographs. In total, 78 patients were included (26 cases and 52 controls). The SRM median of the cases was 76.19 mm (SD: 26.518) and 53.5 mm (SD: 20.47) in controls. A multivariate logistic regression model showed an independent association between APJI and SRM (odds ratio (OR) = 1.033, 95 % confidence interval (CI) 1.007–1.059, p=0.012). Patients with an SRM greater than 60 mm had a 7-fold increase in the odds of APJI (OR = 7.295, 95 % CI = 2.364–22.511, p<0.001). The results of our study suggest an association between large SRM at the hip and the risk of APJI in patients with primary total hip arthroplasty. SRM may be a helpful and easy tool for evaluating the risk of APJI before elective primary total hip replacement surgery.

Greater Knee Soft Tissue Thickness Predisposes Patients to Subsequent Periprosthetic Joint Infection After Total Knee Arthroplasty

BACKGROUND

Although obesity is a risk factor for periprosthetic joint infection (PJI) after total knee arthroplasty (TKA), the role of soft tissue thickness (STT) at the surgical site has not been well studied. This study examined if increased STT in the medial and anterior aspects of the knee are independent risk factors for PJI.

METHODS

A retrospective study was conducted on 206 patients who underwent 2-stage exchange arthroplasty for PJI from 2000 to 2015. They were matched 1:3 to a control group of primary, noninfected TKA patients with minimum 2 years infection-free survival by age, gender, age-adjusted Charlson Comorbidity Index, date of surgery, and body mass index (BMI). Two blinded orthopedic surgeons measured the medial STT from the medial aspect of the knee at the level of the joint line on an anteroposterior radiograph, and anterior STT 8 cm above the joint line on a lateral radiograph from the skin to the quadriceps tendon.

RESULTS

Increased STT was significantly associated with a higher risk for PJI. The mean anterior STT was 29.74 ± 13.76 mm in the PJI group and 24.88 ± 9.76 mm in the control group. The mean medial STT was 42.42 ± 14.66 mm for PJI and 37.27 ± 12.51 mm for control. Both STT measurements were significantly higher in PJI cases with BMI <30 kg/m² vs control patients with BMI <30 kg/m².

CONCLUSION

Anterior and medial knee STT was an independent risk factor for PJI after primary TKA and represents a simple radiographic method to assess postoperative infection risk. Excess adipose tissue around the surgical site can predispose patients to PJI after TKA regardless of BMI.

Pretubercular Subcutaneous Thickness Is a Protective Factor for Superficial Wound Complications After Total Knee Arthroplasty in Nonmorbidly Obese Patients

BACKGROUND

Anterior knee subcutaneous thickness has been associated with increased risk of early reoperation for surgical site infection after primary total knee arthroplasty (TKA) in morbidly obese patients. However, most patients undergoing TKA are not morbidly obese. The aims of this study were to (1) assess the association between anterior knee subcutaneous thickness and early superficial wound complications and (2) determine a threshold value for anterior knee subcutaneous thickness measures that can assist in preoperative risk stratification in nonmorbidly obese TKA patients.

METHODS

Using retrospective analysis, we reviewed 494 primary TKAs performed in patients with a body mass index <40 kg/m² at our institution from January 1, 2010 to December 31, 2017. All patients developing a superficial surgical site infection within 90 days of index arthroplasty requiring treatment with antibiotics or reoperation were identified. Prepatellar thickness and pretubercular thickness were measured on preoperative lateral radiographs and associated with 90-day superficial wound complications.

RESULTS

Sixty-two of the 494 patients developed a superficial wound complication within 90 days of index arthroplasty. TKA patients in the superficial wound complication group had significantly less pretubercular thickness (P = .027). Risk of developing 90-day superficial wound complication was 1.85-fold lower when pretubercular thickness was ≥12 mm (P = .028). Prepatellar thickness (P = .895) was not significantly associated with superficial wound complications.

CONCLUSION

Increased pretubercular thickness is a protective factor for developing superficial wound complications, with 12 mm being an ideal threshold value for preoperative risk stratification in nonmorbidly obese patients undergoing primary TKA surgery.

Does peritrochanteric fat thickness increase the risk of early reoperation for infection or wound complications following total hip arthroplasty?

Background

Radiographically measured subcutaneous peri-incisional tissue depth has been correlated with post-operative surgical site infection after cardiac, cervical spine, and total knee surgery. Its impact following primary total hip arthroplasty (THA) has not been studied. We compare the interobserver reliability of measuring peritrochanteric fat thickness on pre-operative radiographs and hypothesize that these measurements are a reproducible way to predict acute post-operative wound complications and infection in patients undergoing THA.

Methods

A retrospective case-control analysis was performed at a single institution. Patients taken to the operating room within 90 days of their primary THA for a wound complication or deep infection between 2008 and 2016 were identified. Patients <18 years old, those with history of open surgery on the affected hip, or with inadequate radiographs were excluded. Patients were matched 1:1 for gender, age, BMI, and ASA score to THA patients without early wound complications.

Results

All radiographic measurements performed were found to have excellent inter-rater reliabilities (range 0.96-0.98). There was no difference in peritrochanteric fat thickness measurements between the two groups including the sourcil to skin surface (89.5 mm vs. 91.9 mm, p = 0.5), tip of greater trochanter to skin surface (52.9 mm vs. 53.7 mm, p = 0.8), and lateral greater trochanter to skin surface (36.0 mm vs. 37.8 mm, p = 0.6) measurements.

Conclusion

Contrary to other previously reported surgical procedures, radiographic measurement of subcutaneous depth is not a valid tool for predicting a return to the OR for wound complications in the early post-operative period following primary total hip arthroplasty.

Obesity as predictor of postoperative outcomes in liver transplant candidates: Review of the literature and future perspectives

BACKGROUND

Current American and European guidelines consider a pre-transplant BMI ≥40kg/m² as a relative contraindication for liver transplantation but this recommendation is graded as uncertain and requires further research. Moreover, conflicting results are reported on the predictive value of BMI 30-39.9kg/m² on post-transplant complication and mortality risk.

AIM

This study analyzed the data of the literature on the effect of all three BMI classes of obesity on postoperative outcomes in liver transplantation.

MATERIALS AND METHODS

A PubMed and Cochrane Library search was conducted from inception to October 2015.

RESULTS

Analysis of the literature demonstrates that discrepancies among studies are mainly either due to limitations of BMI per se, the different BMI cut-offs used to select patients with obesity or reference group and the different outcomes considered. Moreover, the evaluation of visceral adipose tissue and the detrimental effect of muscle mass reduction in presence of obesity are never considered.

CONCLUSIONS

BMI assessment should be used as a preliminary method to evaluate obesity. Subsequently, the assessment of visceral adipose tissue and muscle mass should complete the preoperative evaluation of liver transplant candidates. This innovative approach could represent a new field of research in liver transplantation.

Subcutaneous Fat Thickness Is Associated With Early Reoperation and Infection After Total Knee Arthroplasty in Morbidly Obese Patients

BACKGROUND

Morbid obesity has been associated with increased complications after primary total knee arthroplasty (TKA), but previous studies have failed to take factors such as body composition and fat distribution into consideration. The aims of this study were to (1) assess the interobservable and intraobservable reliabilities of measuring anterior knee subcutaneous fat thickness on lateral knee radiographs and (2) determine if these measurements associate with early complications in patients with morbid obesity.

METHODS

Using a retrospective case-control analysis, we reviewed 1689 primary TKAs performed in morbidly obese patients at our institution from 1995 to 2012. All patients (n = 58) who required reoperation for wound complication or infection within 90 days were compared to a matched cohort of morbidly obese patients who did not require early reoperation. Distances from patella skin (prepatellar thickness) and tibial tubercle skin (pretubercular thickness) were measured on routine lateral knee radiographs and associated with outcomes.

RESULTS

Intraobserver and interobserver reliabilities were excellent for both measurements. Knees in the reoperation group had significantly greater prepatellar (P = .0001) and pretubercular (P = .0006) soft tissue thickness. Prepatellar thickness ≥15 mm and pretubercular thickness ≥25 mm increased the risk of early reoperation by 2.0× (P = .0003) and 1.6× (P = .023), respectively, and were more predictive measurements than body mass index.

CONCLUSION

Anterior knee subcutaneous fat thickness can be reproducibly measured on lateral knee radiographs and is associated with a significantly increased risk of early reoperation for wound complications and infection after primary TKA in morbidly obese patients.