The one-stop trial will assess the one-stop strategy, which is designed to decrease waiting time and improve cost-effectiveness for surgical outpatient treatment.
Two studies have assessed a one-stop approach for surgical conditions involving the abdominal wall, pilonidal sinus, soft-tissue tumours, or proctologic disease [1, 2].
In a Spanish study the delay from referral until surgery was reduced by 60% and the number of trips for appointments was reduced by 66.6% . Because of its feasibility, acceptability, and cost-efficiency, the direct referral system has the potential to improve relations between primary and specialised care and enhance the quality of care by shortening the delay to treatment. In a study from 2004, patients were sent an appointment for "one-stop" inguinal hernia treatment . It was concluded that patients with unilateral primary inguinal hernias can be seen, assessed and treated on the same day. One-stop inguinal hernia surgery reduces the number of patient visits to the hospital and could be expanded to incorporate many more hernia repairs and other day case procedures.
Other surgical conditions have also been shown to be suitable for improved referral routines, communication and patient logistics between the primary and secondary interface. Better communication between referral centres and GPs combined with continuing medical education programmes may be useful tools to improve appropriate management for surgical patients with faecal incontinence . One-stop clinics have been reported to improve examination and treatment of patients with head and neck lumps [9, 10]. Rectal bleeding clinics can facilitate early diagnosis of colorectal malignancy and can also provide a "one-stop shop" for treating benign anorectal conditions [11–14]. A recent study  is presenting the "Lower Gastrointestinal Electronic Referral Protocol" which was developed to be used alongside the national Choose and Book programme . A dedicated referral protocol addressing all colorectal symptoms would significantly reduce delays in patient pathways with 'straight to test' in secondary care .
A general-practice-led model of integrated care can significantly reduce outpatient attendance while improving patient experience for patients with menorrhagia [17, 18]. For patients with lower urinary tract symptoms and hematuria, a guideline-based open-access investigation service streamlined the process of outpatient referral and resulting in a decrease in waiting time and fewer outpatient investigations . For patients with breast lumps, a one-stop clinic approach and referral guidelines have been shown to be feasible [20–22].
After the introduction of the Norwegian Health Care network, all referrals and discharge letters from hospitals in North Norway are sent electronically between primary and secondary care. Despite this improvement, poor communication often results in inefficiencies and unsatisfactory outcomes. Studies show that both referral and discharge letters were missing vital medical information, referral letters to such an extent that it might represent a health hazard to older patients . Furthermore, poor communication results in unnecessary consultations, as well as delay in diagnosis and treatment [24–26].
This study is defined as a complex intervention, i.e. an intervention that includes several components (guidelines, electronic standardised referral and booking for outpatient surgery) . This trial is directed at health professional behaviour with a strategy for implementing guidelines and computerised decision support. According to Campbell et al., it is useful to consider the process of development and evaluation of such interventions as having several distinct phases (theory, modelling, exploratory trial, definitive randomised controlled trial and long-term implementation). In this trial we will follow these phases, where this study protocol describes these phases and how we will conduct the definitive randomised trial.
An important decision in trials of complex interventions is whether health outcome needs to be assessed. In this "one-stop trial", all patients are receiving the same treatment (day case surgery) in both trial arms. In our opinion it is therefore sufficient to investigate the possible change of health care behaviour, decreased waiting time and increased cost benefit induced by the intervention.
In this trial we chose a RCT design involving nonpharmacologic treatment based upon the CONSORT guidelines . We found that a cluster randomised trial was not feasible, to avoid bias among the clusters and difficulties in estimating within and between cluster components of variance. A cluster randomised trial would also increase the sample size [28–30]. The primary consequence of adopting a cluster randomised design is that it is not as statistically efficient and has a lower statistical power than a randomised trial of equivalent size .
A trial has reported a negative outcome of implementing referral guidelines among GPs for patients with lower bowel symptoms. In this study GPs were offered an electronic interactive referral pro forma. This interactive electronic referral was not integrated in the electronic health record . However, in the present one-stop trial guidelines, electronic referral and booking will be fully integrated in the GP's electronic health records. This will decrease workload and probably increase enthusiasm among the GPs participating in the project.