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To systematically review the current demographics, treatment and mortality rate associated with xanthogranulomatous pyelonephritis (XGP) and to test the hypothesis that the weighted pooled peri-operative mortality rate will be10%.Searches were performed of the Cochrane, Embase and Medline databases and the grey literature for studies published during the period 1 January 2000 to 30 August 2021. Eligible studies reported cohorts of ≥10 predominantly adult patients with XGP and described either average patient age or mortality rate.In total, 40 eligible studies were identified, representing 1139 patients with XGP. There were 18 deaths, with a weighted pooled peri-operative mortality rate of 1436 per 100 000 patients. The mean age was 49 years, 70% of patients were female and 28% had diabetes mellitus. The left kidney was more commonly affected (60%). Four patients had bilateral XGP, and all of whom survived. Renal or ureteric stones were present in 69% of patients, including 48% with staghorn calculi. Urine culture was positive in 59% of cases. Fistulae were present in 8%. Correct preoperative diagnosis occurred in only 45% of patients. Standard treatment continues to comprise a short cause of antibiotics and open radical (total) nephrectomy. Preoperative decompression occurred in 56% of patients. When considered at all, laparoscopic nephrectomy was performed in 34% of patients. Partial nephrectomy was conducted in 2% of patients.Xanthogranulomatous pyelonephritis has a lower mortality rate than historically reported. A typical patient is a woman in her fifth or sixth decade of life with urolithiasis. While open radical nephrectomy remains the most common treatment method, laparoscopic, and to a lesser degree partial nephrectomy, are feasible in well selected patients.

This case report describes a rare cystoscopic finding in an octogenarian, presenting initially with nonspecific lower urinary tract symptoms. Physical examination did not reveal any abnormal skin or mucoepi-dermoid pigmentation. Routine ultrasound identified cystic changes in the bladder prompting cystoscopic investigation. Flexible cystoscopy identified melanin deposits within the bladder mucosa, and biopsy subsequently confirmed a diagnosis of bladder melanosis. The authors of this report wish to add to the available literature on this extremely rare finding in the hope a more robust evidence base would allow a protocol to be established for follow-up. The ultrasound findings reported in this study have not been previouslyreported and may benefit future guidelines on diagnosis.

Ureteric stents play an essential role in urology. However, patients can suffer a range of stent-related symptoms with stent in situ and during removal. Conventional ureteric stents are removed using a flexible cystoscopy, whereas magnetic stents may be rapidly removed with a smaller catheter-like retrieval device. The primary aim of this systematic review was to compare the morbidity including pain associated with conventional versus magnetic ureteric stents. The secondary aim was cost comparison. Searches were performed across databases, including Medline, Scopus, Embase and Cochrane. This review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The search from the 5 databases returned a total of 358 articles. After duplicates were removed as well as the inclusion and exclusion criteria applied, a total of 6 studies were included in the final review. Ureteric Stent Symptoms Questionnaire (USSQ) and Visual Analogue Score (VAS) were used in most of the studies. All the studies reported that magnetic ureteric stents resulted in a reduction in the pain on the removal of magnetic ureteric stents, and no statistically significant difference with indwelling ureteric stents. Furthermore, majority of the studies reported a reduction in the cost associated with magnetic ureteric stents. There is no significant difference in pain from indwelling ureteric stents. There is a reduction in pain with the removal of magnetic ureteric stents compared to conventional removal via cystoscopy and an associated reduction in cost.

Urolithiasis can be a painful condition associated with significant individual and health care burdens. Several studies have shown that anxiety and depression, termed psychological distress, may be associated with urolithiasis. However, there is little consensus on this relationship. We performed a systematic review and meta-analysis on the relationship between urolithiasis and psychological distress and examined rates of psychological distress in this population.We searched online databases including MEDLINE (via PubMed), Embase (via Ovid), Web of Science, and the Cochrane Library with predefined search criteria up to March 2022 utilizing the Preferred Reporting Items for Systematic Review and Meta-analyses. Forty-nine peer-reviewed publications were included in this review. We performed a narrative synthesis on included studies, and a random-effects meta-analysis to obtain a single summary estimate for the relationship between urolithiasis and anxiety.Narrative synthesis found evidence for a relationship between urolithiasis and psychological distress, both anxiety and depression. Meta-analysis of 7 studies found a moderate pooled association between urolithiasis and state anxiety. Additionally, higher proportions of urolithiasis patients experienced psychological distress compared to nonurolithiasis samples across studies. Our findings are limited by the observed heterogeneity in assessment protocols within the data set.Our findings suggest a moderate but significant association between anxiety and urolithiasis, as well as a greater than expected number of urolithiasis patients experiencing psychological distress. More high-quality research studies are required to better understand factors that may influence the relationship between urolithiasis and psychological distress.

Objective To systematically evaluate the spectrum of models providing dedicated resources for emergency urological patients (EUPs). Methods A search of Cochrane, Embase, Medline and grey literature from January 1, 2000 to March 26, 2019 was performed using methods pre-published on PROSPERO. Reporting followed Preferred Reporting Items for Systematic Review and meta-analysis guidelines. Eligible studies were articles or abstracts published in English describing dedicated models of care for EUPs, which reported at least one secondary outcome. Studies were excluded if they examined pathways dedicated only to single presentations, such as torsion, or outpatient solutions, such as rapid access clinics. The primary outcome was the spectrum of models. Secondary outcomes were time-to-theatre, length of stay, complications and cost. Results Seven studies were identified, totalling 487 patients. Six studies were conference abstracts, while one study was of full-text length but published in grey literature. Four distinct models were described. These included consultant urologists allocated solely to the care of EUPs (“Acute Urological Unit”) or dedicated registrars or operating theatres (“Hybrid structures”). In some services, EUPs bypassed emergency department assessment and were referred directly to urology (“Urological Assessment Unit”) or were managed by other dedicated means. Allocating services to EUPs was associated with reduced time-to-theatre, length of stay and hospital cost, and improved supervision of junior medical staff. Conclusion Multiple dedicated models of care exist for EUPs. Low-level evidence suggests these may improve outcomes for patients, staff and hospitals. Higher quality studies are required to explore patient outcomes and minimum requirements to establish these models.

Purpose: The purpose of this study was to evaluate the psychological distress of urological and uro-oncological patients undergoing surgery. Methods: Patients who presented to Mercy University Hospital from October 2019–May 2020 were consecutively recruited. Demographic and clinical characteristics including age, gender, marital status, type of surgery (uro-oncology or general urology), endoscopy or open surgery were gathered. Mood was evaluated using the Hospital Anxiety and Depression Scale prior to admission, prior to discharge and 6 weeks post-surgery. Results: A total of 118 participants (79.7% male) completed the Hospital Anxiety and Depression Scale prior to admission, prior to discharge and at 6 weeks post-surgery. Forty patients (33.9%) underwent uro-oncology-related surgery. At pre-admission 39 patients (33%) fell into a possible-probable clinical category for anxiety and 15 (12.7%) for depression. Older patients had significantly lower anxiety levels than younger patients ( p⩽0.01). There were no differences between patients undergoing uro-oncology or more general urology surgery and levels of anxiety or depression. Repeated measures analysis of variance with age as a covariate indicated no significant differences in Hospital Anxiety and Depression Scale anxiety scores over time. There was a statistically significant reduction in Hospital Anxiety and Depression Scale depression scores over the three assessment time points ( p=0.004). Conclusion: Over one-third of patients were experiencing moderate to severe levels of psychological distress pre-surgery – higher than levels previously reported in uro-oncological patients. Surprisingly, there was no difference in anxiety and depression scores in uro-oncology and urology patients. Psychological distress in both uro-oncology and more general urology patients should be considered in the surgical setting. Level of evidence Moderate

Introduction: Elevated intrarenal pressure (IRP) during flexible ureterorenoscopy (FURS) is a predictor of postoperative complications. The aim of this study is to evaluate IRP during FURS in a por...

The importance of the patient experience is increasingly being recognised. However, there is a dearth of studies regarding factors affecting patient-reported outcomes in emergency general surgery (EGS), including none from the Southern Hemisphere. We aim to prospectively assess factors associated with patient satisfaction in this setting. In this prospective cross-sectional study, all consecutive adult patients admitted to an acute surgical unit over four weeks were invited to complete a validated Patient-Reported Experience Measures questionnaire. These were completed either in person when discharge was imminent or by telephone 50 years, sufficient analgesia, satisfaction with the level of senior medical staff, important questions answered by nurses and confidence in decisions made about treatment. Three identified factors were new: sufficient privacy in the emergency department, sufficient notice prior to discharge and feeling well looked after in hospital. Factors associated with patient satisfaction were identified at multiple points of the patient journey. While some of these have been reported in similar studies, most differed. Hospitals should assess factors valued by their EGS population prior to implementing initiatives to improve patient satisfaction.

Introduction and hypothesis We aim to review iatrogenic bladder and ureteric injuries sustained during caesarean section and hysterectomy. Methods A search of Cochrane, Embase, Medline and grey literature was performed using methods pre-published on PROSPERO. Eligible studies described iatrogenic bladder or ureter injury rates during caesarean section or hysterectomy. The 15 largest studies were included for each procedure sub-type and meta-analyses performed. The primary outcome was injury incidence. Secondary outcomes were risk factors and preventative measures. Results Ninety-six eligible studies were identified, representing 1,741,894 women. Amongst women undergoing caesarean section, weighted pooled rates of bladder or ureteric injury per 100,000 procedures were 267 or 9 events respectively. Injury rates during hysterectomy varied by approach and pathological condition. Weighted pooled mean rates for bladder injury were 212–997 events per 100,000 procedures for all approaches (open, vaginal, laparoscopic, laparoscopically assisted vaginal and robot assisted) and all pathological conditions (benign, malignant, any), except for open peripartum hysterectomy (6,279 events) and laparoscopic hysterectomy for malignancy (1,553 events). Similarly, weighted pooled mean rates for ureteric injury were 9–577 events per 100,000 procedures for all hysterectomy approaches and pathologies, except for open peripartum hysterectomy (666 events) and laparoscopic hysterectomy for malignancy (814 events). Surgeon inexperience was the prime risk factor for injury, and improved anatomical knowledge the leading preventative strategy. Conclusions Caesarean section and most types of hysterectomy carry low rates of urological injury. Obstetricians and gynaecologists should counsel the patient for her individual risk of injury, prospectively establish risk factors and implement preventative strategies.

Background Important incidental pathology requiring further action is commonly found during appendicectomy, macro- and microscopically. We aimed to determine whether the acute surgical unit (ASU) model improved the management and disclosure of these findings. Methods An ASU model was introduced at our institution on 01/08/2012. In this retrospective cohort study, all patients undergoing appendicectomy 2.5 years before (Traditional group) or after (ASU group) this date were compared. The primary outcomes were rates of appropriate management of the incidental findings, and communication of the findings to the patient and to their general practitioner (GP). Results 1,214 patients underwent emergency appendicectomy; 465 in the Traditional group and 749 in the ASU group. 80 (6.6%) patients (25 and 55 in each respective period) had important incidental findings. There were 24 patients with benign polyps, 15 with neuro-endocrine tumour, 11 with endometriosis, 8 with pelvic inflammatory disease, 8 Enterobius vermicularis infection, 7 with low grade mucinous cystadenoma, 3 with inflammatory bowel disease, 2 with diverticulitis, 2 with tubo-ovarian mass, 1 with secondary appendiceal malignancy and none with primary appendiceal adenocarcinoma. One patient had dual pathologies. There was no difference between the Traditional and ASU group with regards to communication of the findings to the patient (p = 0.44) and their GP (p = 0.27), and there was no difference in the rates of appropriate management (p = 0.21). Conclusion The introduction of an ASU model did not change rates of surgeon-to-patient and surgeon-to-GP communication nor affect rates of appropriate management of important incidental pathology during appendectomy.

BACKGROUND Few large Australian studies have explored the impact of acute surgical unit (ASU) model in appendicitis. METHODS An ASU model commenced practice at our institution on 1 August 2012. In this retrospective cohort study, patients undergoing appendicectomy 2.5 years before (Traditional group) or after (ASU group) this date were compared. Primary outcomes were median length of stay, median time from emergency department referral to theatre start and proportion of cases performed in-hours. Secondary outcomes were rates of complications, open appendicectomy, consultant scrubbed for procedure, intensive care unit admission and re-presentation to emergency department within 30 days. RESULTS After removing those with incomplete data, 1214 patients were enrolled; 465 in the Traditional group and 749 in the ASU group. There were no significant baseline differences between groups. Compared with the Traditional group, ASU patients had similar length of stay (1.81 versus 1.81 days; P = 0.54) and time to theatre (0.59 versus 0.56 days; P = 0.14), but a greater proportion of in-hours operation (72% versus 79%; P = 0.014). The ASU group also experienced fewer complications (9% versus 6%; P = 0.031), fewer primary open (4% versus 1%; P < 0.0001) or conversion-to-open appendicectomies (6% versus 2%; P < 0.0005) and had superior rates of consultant scrubbed in theatre (21% versus 56%; P < 0.00001). Rates of intensive care unit admission (1% versus 1%; P = 0.72) and re-presentation were unchanged (5% versus 5%; P = 0.46). CONCLUSION In our institution, the introduction of an ASU model was associated with more in-hours operations and safer care for patients undergoing appendicectomy.

A renal pseudotumour is any apparent renal mass that simulates a tumour on radiological imaging but is composed of normal tissue. Renal pseudotumours may be inflammatory, vascular, postsurgical or congenital. We report a case of renal lobar dysmorphism (RLD) of the kidney, a congenital renal pseudotumour. A 45-year-old man presented with scrotal swelling. Testicular ultrasound showed an epididymal cyst. Renal ultrasound showed a right solid renal apparent mass of 2.4 cm in diameter. Triphasic renal CT showed this was consistent with RLD. Intravenous urography confirmed a central calyx within the dysmorphic lobe. RLD is a rare congenital normal anatomical variant, which can appear as a renal pseudotumour. No further investigation or intervention is necessary. We present the radiological findings of RLD and review the literature.

To objectively and subjectively assess the performance and surgical outcomes of the new Innovex EU-scope™ single-use digital flexible ureteroscope (fURS). A prospective cohort study was carried out (August 2019 to May 2020). The new single-use fURS (Innovex Medical Devices Co. Shanghai, China) was analysed with regard to visibility, manoeuvrability, laser interference and overall performance using a validated Likert scale. Outcomes are compared to the LithoVue™ (Boston Scientific, Marlborough, MA). One hundred patients were included in this study. 50 cases underwent retrograde fURS using the Innovex EU-scope™ and 50 with the LithoVue™. There were no differences in the patient demographics data, or operative data between the two groups. The Innovex EU-scope™ scored higher visibility scores compared to the LithoVue™, median 4, interquartile range (IQR) (4–4), vs. 3.5, IQR (3–5), p = 0.5086. Both scopes had similar manoeuvrability scores. The Innovex EU-scope™ scored significantly lower with regard to comfort compared to the LithoVue, median 4 IQR (3–4) vs. 4.5 IQR (4–5), p = 0.0445. Whereas, laser interference, affected the Innovex much less than the LithoVue™. Both scopes scored well for overall performance. The median overall performance score for the Innovex was 4 IQR (4–4) vs. 4 IQR (4–5). This Innovex EU-scope™ has good objective and subjective visibility and manoeuvrability profiles. This single-use flexible ureteroscope may achieve similar clinical outcomes to an established single use instrument.

The importance of the patient experience is increasingly being recognised. However, there is a dearth of studies regarding factors affecting patient-reported outcomes in emergency general surgery (EGS), including none from the Southern Hemisphere. We aim to prospectively assess factors associated with patient satisfaction in this setting.In this prospective cross-sectional study, all consecutive adult patients admitted to an acute surgical unit over four weeks were invited to complete a validated Patient-Reported Experience Measures questionnaire. These were completed either in person when discharge was imminent or by telephone 4 weeks post-discharge. Responses were used to determine factors associated with overall patient satisfaction.From 146 eligible patients, 100 (68%) completed the questionnaire, with a mean overall satisfaction score of 8.3/10. On multivariate analyses, eight factors were significantly associated with increased overall satisfaction. Five of these were similar to those previously prescribed by other like studies, being patient age 50 years, sufficient analgesia, satisfaction with the level of senior medical staff, important questions answered by nurses and confidence in decisions made about treatment. Three identified factors were new: sufficient privacy in the emergency department, sufficient notice prior to discharge and feeling well looked after in hospital.Factors associated with patient satisfaction were identified at multiple points of the patient journey. While some of these have been reported in similar studies, most differed. Hospitals should assess factors valued by their EGS population prior to implementing initiatives to improve patient satisfaction.

BACKGROUND The acute surgical unit (ASU) model has been associated with improved outcomes for emergency general surgical patients. Few Australasian studies have investigated patients with cholecystitis and none from South Australia. METHODS A retrospective cohort study compared patients admitted to our institution with acute cholecystitis during the 2 years before (traditional period) and after (ASU period) introduction of an ASU on 1 August 2012. Primary outcomes were length of stay, rates of definitive surgery on index admission, time to definitive surgery and proportion of cases performed in-hours. Secondary outcomes were time from emergency department referral to admission, time from radiologically confirmed diagnosis to theatre start, rates of conversion to open cholecystectomy, complications and cholelithiasis-related representations while awaiting definitive procedure. RESULTS A total of 319 patients met the inclusion criteria; 172 and 147 pre- and post-ASU introduction, respectively. Compared with the traditional period, ASU patients had shorter length of stay (3.80 versus 2.83 days, P < 0.0001), higher rates of surgery on index admission (70.9% versus 95.3%, P < 0.0001), shorter time to definitive surgery (28.1 versus 22.1 days, P < 0.001), lower rates of conversion to open cholecystectomy (18.0% versus 7.1%, P = 0.007) and fewer complications (24.4% versus 6.1%, P < 0.0001). Other outcomes were not significantly different. CONCLUSION Introduction of an ASU was associated with superior outcomes amongst patients admitted with acute cholecystitis. These findings extend the literature in support of the current model of care.

OBJECTIVE: To evaluate systematically the safety and efficacy of intra-operative cell salvage (ICS) in urology. METHODS: A search of Medline, Embase and Cochrane Library to August 2017 was performed using methods pre-published on PROSPERO. Reporting followed the Preferred Reporting Items for Systematic Review and Meta-analysis guidelines. Eligible titles were comparative studies published in English that used ICS in urology. Primary outcomes were allogeneic transfusion rates (ATRs) and tumour recurrence. Secondary outcomes were complications and cost. RESULTS: Fourteen observational studies were identified, with a total of 4 536 patients. ICS was compared with no the blood conservation technique (seven studies), preoperative autologous donation (PAD; five studies) or both (two studies). Cohorts underwent open prostatectomy (11 studies), open cystectomy (two studies) or open partial nephrectomy (one study). Meta-analysis was possible only for ATRs within prostatectomy studies. In this setting, ICS reduced ATR compared with no the blood conservation technique (odds ratio [OR] 0.34, 95% confidence interval [CI] 0.15-0.76) but not PAD (OR 0.76, 95% CI 0.39-1.31). In the non-prostatectomy setting, ATRs amongst patients who underwent ICS were significantly higher or similar in one and two studies, respectively. Tumour recurrence was found to be significantly less common (two studies), similar (eight studies) or not measured (four studies). All six studies reporting complications found no difference in their ICS cohorts. Regarding cost, one study from 1995 found ICS more expensive than PAD, while two more recent studies found ICS to be cheaper than no blood conservation technique. As a result of inter-study heterogeneity, meta-analyses were not possible for recurrence, complications or cost. CONCLUSION: Low-level evidence exists that, compared with other blood conservation techniques, ICS reduces ATR and cost while not affecting complications. It does not appear to increase tumour recurrence post-prostatectomy, although follow-up durations were short. Small study sizes and short follow-ups mean conclusions cannot be drawn with regard to recurrence after nephrectomy or cystectomy. Randomized trials with long-term follow-up evaluating ICS in urology are required.

Background: To examine the effect of intra-operative cell salvage (ICS) in open radical prostatectomy. Methods: In this retrospective cohort study, all patients undergoing open radical prostatectomy for malignancy at our institution between 10/04/13 and 10/04/17 were enrolled. Patients were grouped and compared based on whether they received ICS. Primary outcomes were allogeneic transfusion rates, and disease recurrence. Secondary outcomes were complications and transfusion-related cost. Results: Fifty-nine men were enrolled; 30 used no blood conservation technique, while 29 employed ICS. There were no significant differences between groups in age, pre- or post-operative haemoglobin, Charlson comorbidity index, operation duration or length of stay. Tumour characteristics were also similar between groups, including pre-operative prostate specific antigen, post-operative Gleason score, T-stage, nodal status and rates of margin positivity. Compared with controls, the ICS group had longer follow up (945 vs . 989 days; P=0.0016). The control and ICS groups were not significantly different in rates of tumour recurrence (6 vs . 3 patients; P=0.30) or complications (10 vs . 5 patients; P=0.16). While the proportion of patients receiving allogenic transfusion was similar (9 vs . 6 patients; P=0.41), fewer red blood products transfused (40 vs . 12 units) meant transfusion related costs were lower in ICS patients (AUD $47,666 vs . $37,429). Conclusions: ICS reduced transfusion related costs, without affecting allogeneic transfusion rates, tumour recurrence or complication rates. These findings extend the literature supporting ICS in oncological surgery. Prospective randomised studies are needed to confirm the existing level III evidence.

OBJECTIVE: To assess and measure the capability of a single-use disposable digital flexible ureteroscope, the LithoVue™ (Boston Scientific, Marlborough, MA, USA), and to assess if there is a benefit to switching to single-use scopes.PATIENTS AND METHODS: The LithoVue was compared to two commonly used reusable flexible ureteroscopes (Olympus URF-V [Olympus, Tokyo, Japan] and Karl Storz Flex-Xc [Karl Storz & Co. KG, Tuttlingen, Germany]) ex vivo. An analysis of reusable ureteroscope usage was performed to evaluate damage, durability, and maintenance costs. This was then compared to the projected costs of using single-use disposable scopes.RESULTS: Flexion, deflection and irrigation flow of the LithoVue was equivalent, if not better than the reusable flexible ureteroscopes. An analysis of 234 procedures with seven new Olympus URF-V scopes, revealed 15 scope damages. Staghorn stones and lower pole/mid-zone stones were significant risk factors for damage (P = 0.014). Once damage occurred it was likely to occur again. Total repair costs were $162 628 (Australian dollars) (£92 411 in Great British pounds), the mean cost per case was $695 (£395). Factoring in the purchase cost, cleaning and repair costs, the cumulative cost of 28 reusable flexible ureteroscopy procedures was ~$50 000 (£28 412). If the LithoVue was priced at $1 200 (£682), switching to a single-use scope would cost ~$35 000 (£19 888).CONCLUSION: The LithoVue is analogous to reusable flexible ureteroscopes in regard to standard technical metrics. Depending on its purchase cost it may also represent a cost saving for hospitals when compared to the cumulative costs of maintaining reusable scopes. Additionally, urologist may consider using the scope in cases in which reusable scope damage is anticipated.

Objective To quantify the burden of the side effects of radiotherapy on a tertiary referral urology department. Patients and methods A prospective study of all urology admissions to a public urology department at a tertiary hospital in a 6-month period was performed. Patients admitted with complications attributable to radiotherapy were included in the study. Data obtained included patient demographics, radiotherapy details, complication type and management required. Results A total of 1198 patients were admitted; 921 (77%) were elective and 277 (23%) were emergency admissions. Thirteen out of the 921 (1.4%) elective admissions and 20 out of the 277 (7.2%) emergency admissions were attributable to radiotherapy complications. Radiotherapy complications was the fourth most common reason for emergency admission, ahead of acute urinary retention. These 33 admissions were accounted for by 21 patients. A total of 39 separate complications attributable to radiotherapy were diagnosed, with some patients having multiple complications. The median (interquartile range) time to onset of complications was 4 (1-9) years. The surgical intervention rate was 67%. The commonest procedures were washout with/without clot evacuation or diathermy in theatre (15.8%) and urethral dilatation/bladder neck incision (15.8%). Two urinary diversions and two cystoprostatectomies plus urinary diversion were performed. Conclusion Radiotherapy complications are consequential and account for a substantial proportion of a tertiary urology department's emergency workload. These complications generally occur years after radiotherapy and frequently require surgical intervention.

After radical nephrectomy, clear cell renal cell carcinoma (ccRCC) recurs locally in

Objective To systematically review comparative studies on the acute surgical unit (ASU) model. Methods Searches were performed of Cochrane, Embase, Medline and grey literature. Eligible articles were comparative studies of the Acute Surgical Unit (ASU) model published 01/01/2000-12/03/2020. Amongst patients with any diagnosis, primary outcomes were length of stay, after-hours operating, complications and cost. Secondary outcomes were time to surgical review, time to theatre, mortality and re-admission for patients with any diagnosis, and cholecystectomy during index admission for patients with biliary disease. Additional analyses were planned for specific cohorts, such as patients with appendicitis or cholecystitis. Results Searches returned 9,677 results from which 77 eligible publications were identified, representing 150,981 unique patients. Cohorts were adequately homogenous for meta-analysis of all outcomes except cost. For patients with any diagnosis, compared with the Traditional model, the introduction of an ASU model was associated with reduced length of stay (mean difference [MD] 0.68 days; 95% confidence interval [CI] 0.38–0.98), after-hours operating rates (odds ratio [OR] 0.56; 95% CI 0.46–0.69) and complications (OR 0.48, 95% CI 0.33–0.70). Regarding cost, two studies reported savings following ASU introduction, while one found no difference. Amongst secondary outcomes, for patients with any diagnosis, ASU commencement was associated with reduced time to surgical review, time to theatre and mortality. Re-admissions were unchanged. For patients with biliary disease, ASU establishment was associated with superior rates of index cholecystectomy. Conclusion Compared to the Traditional structure, the ASU model is superior for most metrics. ASU introduction should be promoted in policy for widespread benefit.