Predicting necrotising soft tissue infections in people who inject drugs: poor performance of the Laboratory Risk Indicator for Necrotising Fasciitis score and development of a novel clinical predictive nomogram in a retrospective cohort with internal validation.

INTRODUCTION: Necrotising soft tissue infections (NSTI) can threaten life and limb. Early identification and urgent surgical debridement are key for improved outcomes. NSTI can be insidious. Scoring systems, like the Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC), exist to aid diagnosis. People who inject drugs (PWID) are high risk for NSTI. This study aimed to assess the utility of the LRINEC in PWID with lower limb infections and develop a predictive nomogram. METHODS: A retrospective database of all hospital admissions due to limb-related complications secondary to injecting drug use between December 2011 and December 2020 was compiled through discharge codes and a prospectively maintained Vascular Surgery database. All lower limb infections were extracted from this database, dichotomised by NSTI and non-NSTI with the LRINEC applied. Specialty management times were evaluated. Statistical analyses involved: chi-square; Analysis of "variance"; Kaplan-Meier, and receiver operating characteristic curves. Nomograms were developed to facilitate diagnosis and predict survival. RESULTS: There were 557 admissions for 378 patients, with 124 (22.3%; 111 patients) NSTI. Time from admission to: theatre and computed tomography imaging respectively varied significantly between specialties ( P =0.001). Surgical specialties were faster than medical ( P =0.001). Vascular surgery received the most admissions and had the quickest time to theatre. During follow-up there were 79 (20.9%) deaths: 27 (24.3%) NSTI and 52 (19.5%) non-NSTI. LRINEC ≥6 had a positive predictive value of 33.3% and sensitivity of 74% for NSTI. LRINEC <6 had a negative predictive value of 90.7% and specificity of 63.2% for non-NSTI. Area under the curve was 0.697 (95% CI: 0.615-0.778). Nomogram models found age, C-reactive protein, and non-linear albumin to be significant predictors of NSTI, with age, white cell count, sodium, creatinine, C-reactive protein, and albumin being significant in predicting survival on discharge. CONCLUSION: There was reduced performance of the LRINEC in this PWID cohort. Diagnosis may be enhanced through use of this predictive nomogram.

Superior Mesenteric Artery Syndrome Managed with Laparoscopic Duodenojejunostomy.

Background: Superior mesenteric artery (SMA) syndrome is a rare disorder that may be managed surgically if conservative management fails. Different surgical techniques have been described, division of the ligament of Treitz, gastrojejunostomy, and duodenojejunostomy. The aim of this case series is to show that laparoscopic duodenojejunostomy is a safe and technically feasible management for superior mesenteric artery syndrome. Methods: In this case series, we retrospectively identified all patients who underwent laparoscopic duodenojejunostomy for SMA syndrome in our tertiary university center between December 2016 and July 2019. Data collected included demographics, presenting symptoms, comorbidities, pre and postoperative body mass index (BMI), operative approach, operative blood loss, operative duration, clinical and radiological results, in hospital/30-day complications, mortality, and postoperative follow-up outcomes. Results: We identified eleven patients, 10 females and 1 male, with a median age 23 years (range 17-43 years). All patients had refractory symptoms after a minimum of two months of conservative management and subsequently underwent laparoscopic duodenojejunostomy. There were no intraoperative complications and no in-hospital or 30-day postoperative mortality or complications were identified. Follow-up data showed complete resolution in 73% of patients (n = 8) and only one patient with no improvement postoperatively. Results also showed a median BMI increase of 2 kg/m2 (range 1-9 kg/m2) at a median follow-up of 16 months (range 4-48 months). Conclusion: Laparoscopic duodenojejunostomy is a safe treatment option for SMA syndrome and should be considered when patients do not respond to conservative management.