Reducing the rate of negative ureteroscopy: predictive factors and the role of preoperative imaging

INTRODUCTION

The aim of this study was to investigate factors that may predict a negative ureteroscopy (URS) performed for ureteric calculi in prestented patients and to assess preoperative imaging in reducing the rate of negative URS.

METHODS

Data were collected on emergency stent placement for a ureteric calculus from April 2011 to February 2016 (Group A) and October 2016 to October 2019 (Group B). Data included patient demographics, indication for a stent, stone characteristics, baseline bloods, urine culture, readmission, negative URS rate and the use of pre-URS imaging. Multivariate logistic regression was used for statistical analysis.

RESULTS

Of 257 patients who underwent emergency stent insertion, 251 underwent deferred URS for a ureteric calculus and 6 avoided URS due to pre-URS imaging. Indications for stent were pain (42%), sepsis (39%) and acute kidney injury (19%). Mean stone size was 7.8mm, mean stone density was 699 Hounsfield units (HU) and the stone locations were upper (62%), mid (13%) and lower ureter (25%). The overall negative URS rate was 12%. The negative URS rate was lower in patients with pre-URS imaging compared with those with none, 6% and 14%, respectively (OR=2.33, 95% CI: 0.69-7.56, p=0.2214). Logistic regression analysis indicated stone size as the only significant predictor of a negative URS, where the greater the size of the stone the less likely URS would be negative (β=0.75, 95% CI: 0.60-0.94 p=0.011).

CONCLUSIONS

Utilising pre-URS imaging can lead to a reduction in negative URS rate. Stone size <5mm appears to be the subgroup most likely to benefit from imaging.

Single centre versus multi-centre pooled morbidity data in PCNL and the implications for informed consent

Background: National and international outcome data following PCNL have been available for many years, but multi-centre data may not reflect the outcome from an individual surgeon or hospital.Methods: A combination of retrospective and prospective single centre data was collated from 2000-2016 and are compared to large single and multi-centre series.Results: Data were available on 801 unique cases performed between 2000 and 2016, mean age = 55.2 (SD = 14.8) (range = 17-93). The mean change in haemoglobin after PCNL was 1.65 g/dL ± 0.05, n = 630. Twenty-seven patients required a blood transfusion (3.37%). In 470 cases, data on pre-operative urine culture was available. One hundred and nineteen (25%) demonstrated evidence of bacteriuria pre-operatively. The most common isolated species were E. Coli and Proteus Mirabilis. Pre-operative urine infection was associated with a greater drop in haemoglobin following surgery, but this difference was not found to be statistically significant. Changes in serum creatinine and eGFR rise following surgery were calculated. The mean rise was found to be 15.21 µmol/L (SE = 2.08, n = 208). The mean drop in eGFR was estimated to be 7.35 ml/min/1.73 m² (± 0.895, n = 205). Eight cases of 801 (1%) required admission to higher level care. There was one small bowel puncture and one pleural perforation recorded. Sub-selective embolization due to bleeding occurred in six cases (0 .75%) and there were no peri-operative deaths in this series. Published data comparing single centres with > 500 cases are presented.Conclusion: To facilitate transparent consent, single-centre rather than pooled outcome data should be utilized.

The diagnostic yield of computed tomography in the management of acute flank pain and the emergency intervention rate for a proven acute ureteric stone

INTRODUCTION

The diagnostic and management pathways for patients presenting with acute flank pain are complex. Although computed tomography (CT) of the kidneys, ureters and bladder (KUB) is the gold standard investigation for urolithiasis, the multitude of differential diagnoses must also be considered in the context of long-term risk from ionising radiation. This study investigated the integrated role and diagnostic yield of non-contrast CT in cases of acute flank pain.

METHODS

A retrospective cohort study was undertaken of 1,442 consecutive patients investigated with CT KUB between March 2013 and February 2015. The primary outcome was diagnostic yield of CT with secondary outcomes being predictors of need for urological intervention.

RESULTS

A cause for acute flank pain was identified in 717 patients (50%), there was an incidental finding in 389 patients (27%) and normal imaging was reported in 336 patients (23%). A diagnosis was more commonly made in male than in female patients (70% vs 40%) and with increasing age (46% in patients aged <30 years, 56% in those aged 30-49 years and 63% in those aged ≥50 years). The overall rate for an ipsilateral urinary tract stone was 41%. Factors strongly associated with emergency intervention included stone size >10mm (odds ratio [OR]: 11.7, 95% confidence interval [CI]: 3.3-42.7), stones located at the pelviureteric junction (OR: 7.8, 95% CI: 2.6-22.9), C-reactive protein >50mg/l and ≤100mg/l (OR: 15.2, 95% CI: 5.1-45.3), and estimated glomerular filtration rate ≤30ml/min (OR: 5.8, 95% CI: 1.5-21.8).

CONCLUSIONS

This contemporary study identifies age and sex as independent variables affecting the diagnostic yield of CT KUB in cases of acute flank pain, and highlights factors associated with a need for emergency intervention in proven ureteric stones.

Combined antegrade and retrograde access to difficult ureters: revisiting the rendezvous technique

INTRODUCTION

Complex ureteric strictures present a significant challenge to the endourologist and uro-radiologist. Multiple separate interventions to try to cross the stricture are often attempted. We describe our experience managing a heterogenous patient group using the 'rendezvous' procedure.

METHODS AND MATERIALS

16 patients and 18 ureters (one bilateral procedure, and two separate procedures in one patient) underwent rendezvous procedures. Seven patients had coexisting ureteric calculi treated. Each case was followed up for between 3 months and 5 years.

RESULTS

In 16/18 ureters there was technical success at time of surgery; successfully crossing the stricture, allowing ureteroscopic access to the ureter, dilating and/or stenting the ureter. 2/18 were unsuccessful; one secondary to advanced malignancy resulting in a uretero-vaginal fistula and the second a failure to remove a retained, displaced ureteric stent. Of the 18 ureteric procedures; 7/18 were stent free at 3 months, improving to 8/18 stent free at 6 months. 4/18 remained nephrostomy dependent (failure of drainage despite stent or failure to stent) at 3 months, increasing to 6/18 being nephrostomy dependent at 6 months. 1/16 remained dialysis dependent with a nephrostomy tube. For those procedures involving ureteric calculi, 6/7 were stone free and 1/5 had a persistent stone fragment requiring further intervention.

CONCLUSIONS

A combined approach may decrease the number of separate interventions required, with the aim of removing the need for a long-term nephrostomy, as well as providing opportunity to treat ureteric calculi in the context of stricture disease. Our experience has been that where the rendezvous has been required to treat strictures caused by malignant extrinsic compression, stenting has not been successful; this information is key to informed consent in a group of patients who may have a limited life expectancy.

The difficult ureter: what is the incidence of pre-stenting?

INTRODUCTION

Difficulty may be encountered with retrograde access for rigid and flexible ureterorenoscopy (URS) due to anatomic abnormalities, a narrow ureteric lumen, tortuous ureteric path or previous instrumentation. Ureteric dilatation using a balloon or tapered dilator can occasionally fail and will usually lead to the placement of a ureteric stent. We present our experience and incidence of pre-stenting after failed standard access and dilatation techniques, the aim being to quote a figure for the patient at the time of consent.

PATIENTS AND METHODS

Data were collected prospectively from a single surgeon at a regional tertiary referral stone unit. The outcomes of those patients pre-stented, for failed access, were recorded.

RESULTS

Between December 2007 and December 2008, a total of 119 patients underwent flexible and rigid URS. Mean patient age was 49 years (range, 19-86 years). Of these, 107 cases were undertaken for urolithiasis and 12 cases for diagnosis of upper tract malignancy. 12% (13/107) of cases were for pain and non-diagnostic imaging and 8.4% (9/107) of patients were pre-stented because of failed access, without complication, and subsequently had successful interval treatment. Of the remaining successful cases of confirmed urolithiasis, 33% (28/85) and 67% (56/85) were undertaken for ureteric and renal calculi, respectively. Stone clearance rates were 83% (19/23) and 75% (3/4) for lower pole renal calculi 5-10 mm and > 10 mm in size, respectively. The overall clearance rate for lower pole calculi was 81% (22/27). The ureteric stone clearance rate was 86% (24/28) rising to 92% (24/26) in those solitary stones less than 10 mm in size.

CONCLUSIONS

The incidence of ureteric pre-stenting in a tertiary referral unit was 8% and should be considered and indeed discussed with patients when obtaining pre-operative consent, especially for purely elective, non-urgent, upper tract cases. The alternative for these difficult, tight ureters is extensive balloon dilatation, with the risk of trauma and the potential for long-term stricture formation.

A randomized controlled trial of nephrostomy placement versus tubeless percutaneous nephrolithotomy

PURPOSE

We established whether totally tubeless percutaneous nephrolithotomy with no nephrostomy or ureteral stent is a safe management technique.

MATERIALS AND METHODS

Patients were randomized to have a nephrostomy placed (group 1 control) or none (group 2 treatment). A total of 25 patients were randomized to each group. Cases were considered uncomplicated and suitable for randomization if there was no significant bleeding or residual stone load, the pelvicaliceal system was intact and there was no evidence of a residual ureteral stone. The primary outcome measure was length of stay, and secondary outcomes were analgesic requirements and postoperative complications such as bleeding, infection or ureteral obstruction. Hospital readmission rates and stone clearance rates were also recorded.

RESULTS

Mean stone size was 21.6 vs 17.5 mm. There were no transfusions in either group. Hemoglobin change was 2.03 vs 1.18 gm/dl and mean creatinine increase was 0.029 vs -0.111 mg/dl. There were no differences in hemorrhage, infection and serum parameters. There were no readmissions in either group. Mean length of stay was 3.4 vs 2.3 days (p <0.05).

CONCLUSIONS

This trial demonstrates that percutaneous nephrolithotomy without nephrostomy or stent is a safe and well tolerated procedure in selected patients. Length of stay was reduced with no major complications in either group. We believe that totally tubeless percutaneous nephrolithotomy may be considered an accepted standard of care for selected cases and it is possible to reserve placement of a nephrostomy tube or internal ureteral stent for specific indications.

Clostridium difficile in urology

INTRODUCTION

The objective was to determine the incidence of Clostridium difficile infection in a UK urology ward from 2000 to 2005, and correlate and compare the data with other specialty wards and national figures.

PATIENTS AND METHODS

Urology patients with a positive stool culture for C. difficile between 2000 and 2005 were identified from a hospital database. The medical records of these patients were reviewed and data such as antibiotic use, urological diagnosis and elective/emergency status of the patient were recorded and analysed. The number of C. difficile cases on an elderly care ward, an acute medical ward and an acute surgical ward were also recorded for this period. Data on the number of admissions and occupied bed-days on all 4 wards were compared.

RESULTS

There were 33 cases of C. difficile on the urology ward between 2000 and 2005. The incidence of this infection varied between 10.2 and 48.4 cases per 10,000 patient episodes (mean 21.0). There was a significant difference between the number of C. difficile cases per 1000 patient days between the urology ward and the acute medical ward (P = 0.002) and the elderly care ward (P = 0.03).

CONCLUSIONS

There is no evidence to suggest that there has been an increase in the incidence of C. difficile in a UK urology ward. The rates on the urology ward were lower than the national average, and significantly lower than those rates on an acute medical ward and an elderly care ward. There is a 0.21% chance of a patient testing positive for C. difficile during their stay on a urology ward.

Day-case rigid and flexible ureteroscopy

INTRODUCTION

The aim of this study was to evaluate the feasibility of rigid and flexible ureteroscopy as a day-surgery procedure.

PATIENTS AND METHODS

All patients requiring elective ureteroscopy from March 2004 were considered for a day-surgery procedure. The standard day-surgery exclusions existed but there were no urological criteria for exclusion. A single consultant urologist performed or supervised all procedures.

RESULTS

A total of 64 patients underwent 50 rigid and 14 flexible procedures. Six diagnostic ureteroscopies were performed. There was a 96% stone clearance rate. Five patients required an unplanned admission within the first 2 weeks' postoperatively. Three of these patients were admitted on the day of surgery, two for pain and one for social reasons. Two patients were admitted at 24 h and 48 h, respectively, for urinary retention.

CONCLUSIONS

Ureteroscopy, both rigid and flexible, is a safe procedure for the day-surgery setting. Routine use of prophylactic antibiotics, intravenous non-steroidal anti-inflammatory drugs resulted in an acceptable re-admission rate.

A 4-year review of balloon dilation of ureteral strictures in renal allografts

BACKGROUND

Ureteral obstruction necessitating intervention occurs in 2% to 7.5% of all renal allograft recipients. Conventional management includes open surgical repair, although more recently, percutaneous ureteral dilation has been performed.

PATIENTS AND METHODS

The management and outcome of all seven allograft ureteral strictures treated with balloon dilation in our unit over a 4-year period were reviewed. Half (55%) of these strictures occurred in the proximal ureter.

RESULTS

Four strictures were dilated successfully with a requirement for five dilations in total. These patients have stable graft function with no evidence of obstruction. Five strictures persisted despite 11 dilations. There were no significant complications from balloon dilation.

CONCLUSION

Definitive surgical management should be considered if obstruction persists after one attempt at ureteral dilation, as multiple dilations have a low success rate (25%).

A key cause of paraphimosis

A 90-year-old man on hormonal treatment for invasive (T4) adenocarcinoma of the prostate presented as an emergency with a paraphimosis secondary to placement of four circumferential key rings around his penis. He had experienced referred penile pain from his prostate cancer, and to overcome this, had attempted to 'gate out' his pain by constricting his penis and thus stimulating the pudendal nerve. His treatment in our unit consisted of a penile local anaesthetic block, removal of the key rings with a ring cutter and manual reduction of the paraphimosis.

Percutaneous retrograde varicocele embolisation using tungsten embolisation coils: a five year audit

OBJECTIVE

To assess the efficacy of percutaneous retrograde varicocele embolisation using Spirale tungsten coils over a period of five years.

PATIENTS AND METHODS

Fifty consecutive patients underwent local anaesthetic day case varicocele embolisation via a right femoral approach. Venous anatomy was identified and classified. Morbidity and recurrence were recorded at three month clinical follow up.

RESULTS

The procedurewas technically successful in 94% of the patients. The varicocele recurred in 16%, the majority of whom had complex venous anatomy. 8% of the patients complained of discomfort at follow up.

CONCLUSIONS

Although the coils used in this study have been withdrawn, a high technical success rate is described with failure being predominantly due to complex venous anatomy.

Five-year data from the Oxford Laser Prostatectomy Trial

OBJECTIVE

To evaluate the natural history of a group of patients who underwent contact laser prostatectomy or transurethral resection of the prostate (TURP).

PATIENTS AND METHODS

Patients were followed up at 5 years after enrolling in a prospective double-blind randomized controlled trial of TURP vs contact laser prostatectomy.

RESULTS

Of the initial trial patients, 11.5% had died (seven in the laser and 10 in the TURP arm) and eight (5.4%) were too incapacitated by coexistent medical disease to respond to the questionnaires. Thirty-eight patients were not available for follow-up, despite numerous invitations. Thirteen of the laser patients (18%) and 11 of the TURP patients (14.5%) had undergone re-operation. Two patients from each arm had received alpha-blockers for worsening symptoms.

CONCLUSIONS

Five years after prostatic surgery, a significant number of patients were dead or disabled by coexistent medical disease. The re-operation rate after TURP and contact laser prostatectomy were similar.

A double-blind randomized controlled trial and economic evaluation of transurethral resection vs contact laser vaporization for benign prostatic enlargement: a 3-year follow-up

OBJECTIVE

To evaluate the effect of contact laser prostate surgery in the treatment of benign prostatic hyperplasia.

PATIENTS AND METHODS

A prospective double-blind randomized controlled trial of transurethral resection of the prostate (TURP) and contact laser prostatectomy was conducted, with an economic evaluation of both procedures. The primary outcome measure was the change in the American Urologic Association symptom score, with secondary outcome measures being the peak urinary flow rate, treatment-related complications, re-operation rate and health service costs.

RESULTS

The perioperative blood loss and transfusion requirements were statistically significantly lower for laser prostatectomy than for TURP. There was no clinically significant difference between TURP and contact laser prostatectomy in the mean change in symptom scores and flow rates. There were distinct perioperative advantages in favour of the contact laser treatment, but some disadvantages in terms of re-catheterization and re-operation rates.

CONCLUSIONS

Contact laser prostatectomy is a valid treatment for benign prostatic hypertrophy. The performance of contact laser prostatectomy as day-case surgery would have cost advantages to the National Health Service.

An audit of positive findings in flexible and rigid check cystoscopy

Both flexible and rigid cysto-urethroscopy are routinely used in the surveillance of transitional cell bladder tumours. This study addressed the issue of patient selection for either rigid or flexible cystoscopy. What proportion of positive findings at flexible cystoscopy and negative findings at rigid cystoscopy are acceptable? Standards were set of 10% for the former and 50% for the latter and our practice was then audited. A retrospective analysis of 800 patients undergoing check cystoscopy revealed a positive finding rate of 8.3% using the flexible instrument and 48.1% using the rigid instrument.

Severe unremitting cystitis progressing to cystectomy

We report on patients with severe intractable idiopathic cystitis, one of whom progressed to cystectomy. The implications of non-infective, non-interstitial cystitis are discussed.

Evaluation of index and profile measures of health status in a randomized controlled trial. Comparison of the Medical Outcomes Study 36-Item Short Form Health Survey, EuroQol, and disease specific measures

OBJECTIVES

The authors compare two generic measures of health status with disease-specific measures in a randomized controlled trial of transurethral resection of the prostate with laser vaporization prostatectomy for benign prostatic hypertrophy.

METHODS

Patients entered into the trial completed the following questionnaires prior to treatment and at follow-up at 3 months and 1 year. The Medical Outcomes Study 36-Item Short Form Health Survey (SF-36) is a generic measure that produces an eight-dimension profile as well as two summary measures of health status (the physical component score and the mental component score). The EuroQol provides two single index measures of health status; one intended to convey the utility (or lack of) that an individual derives from his or her own health state compared with alternative states and a second simple visual analog scale "thermometer" of health status. The American Urological Association symptom score and the Bothersome index are disease-specific indices of health status for use specifically with benign prostatic hypertrophy patients.

RESULTS

The EuroQol indicates no statistically significant improvements with time for either arm of the trial. The SF-36 physical and general health perceptions domains indicates statistically significant improvements for the transurethral resection of the prostate arm alone at 3 months and 1 year, as do the physical summary score at the 3-month follow-up visit. The effect sizes of these improvements, however, are small, using standard criteria. In contrast, statistically significant differences are found with time for both transurethral resection of the prostate and laser prostatectomy on both disease-specific measures, which also indicate statistically significant superior outcome for the transurethral resection of the prostate arm compared with the laser arm.

CONCLUSIONS

The results indicate that the disease-specific measures are more sensitive to change than the generic measures of outcome. Possible explanations for this are discussed.

The Oxford Laser Prostate Trial: economic issues surrounding contact laser prostatectomy

OBJECTIVE

To compare the economic implications of transurethral resection of the prostate (TURP) and contact-laser vaporization of the prostate (with the SLT system) using data obtained from a randomized controlled trial.

METHODS

All aspects of management before, during and after surgery on 102 patients, followed up for 3 months, were costed and analysed. Based on the data from the trial, the mean costs were calculated. A sensitivity analysis was then performed to examine the effect of changes in some of the relevant variables. The mean difference in cost between laser treatment and TURP was plotted against the cost of laser consumables, assuming a 5% re-operation rate for both operations at 5 years and a 5% discount rate. A range of laser re-operation rates was compared with the mean difference in costs, assuming a hospital stay of one night and two district-nurse visits. Other assumptions on discounts and re-operation rates, based on collected data, were also tested.

RESULTS

TURP will remain more economical until the cost of laser consumables is reduced to 20% of the current list price, or a hospital stay of one night is introduced.

CONCLUSIONS

The costs of contact-laser vaporization of the prostate are likely to exceed the costs of TURP unless laser treatment is accompanied by a more active approach to post-operative management, including a hospital stay of one night and, if necessary, the removal of the patient's catheter at home by a district nurse.

The Oxford Laser Prostate Trial: a double-blind randomized controlled trial of contact vaporization of the prostate against transurethral resection; preliminary results

OBJECTIVE

To compare the results of contact laser vaporization and transurethral resection of the prostate (TURP) in a double-blind randomized controlled clinical trial.

PATIENTS AND METHODS

The study comprised 148 patients with clinical benign prostatic hypertrophy (BPH) who were recruited and allocated randomly to undergo either TURP (72 patients) or laser ablation of the prostate (76 patients). The outcome was assessed using the American Urological Association (AUA -7) symptom score after 1 and 3 months as the primary measure and by urinary flow rates, haematological factors and the duration of hospital stay and length of catheterization.

RESULTS

With 90% statistical power, the results at 3 months showed no clinical or statistical difference between the treatments in change in AUA symptom score. A lower blood loss, hospital stay and duration of catheterization significantly favoured the laser treatment, although the failure rate of trial without catheter and the rate of re-operation were higher after laser treatment.

CONCLUSIONS

These early data are encouraging for this technique, although the outcome after one year requires evaluation before advocating the widespread uptake of this method.

The Oxford Laser Prostate Trial: sexual function data from a randomized controlled clinical trial of contact laser prostatectomy

OBJECTIVE

To examine the effects of contact laser vaporization prostatectomy and transurethral resection of the prostate (TURP) on sexual function and to examine their association with treatment satisfaction.

METHODS

Data on sexual function were collected pre-operatively and 3 months after contact laser vaporization prostatectomy or TURP. The sexual outcome was examined in relation to satisfaction with treatment and quality of life.

RESULTS

A wide variation in sexual function was seen at baseline with overall 45% of the patients being impotent during the previous year and 49% claiming to not always have erections when stimulated 1 month prior to surgery. At 3 months postoperatively, 4% of the laser and 3% of the TURP patients who were previously potent were now impotent. There were no statistically significant associations between preoperative or postoperative (3 months) sexual function and either age, preoperative catheterization, or prostate volume.

CONCLUSION

The impotence rate 1 month prior to surgery is higher than in previous reports, and the impotence rate after contact laser prostatectomy in this sample size is similar to that seen following TURP.

The Oxford Laser Prostate Trial: sensitivity to change of three measures of outcome

OBJECTIVES

To evaluate the sensitivity to change of outcome measures in a double-blind randomized controlled trial of transurethral resection of the prostate (TURP) and contact laser prostatectomy.

METHODS

A total of 152 patients were randomized to TURP or contact laser prostatectomy using the Surgical Laser Technology (SLT) system. Preoperative data were obtained using a self-administered questionnaire containing the American Urological Association (AUA-7) symptom score, the bothersome score (benign prostatic hyperplasia impact index), and the Short Form-36 health status questionnaire (SF-36). Follow-up was at 1 and 3 months. Effect size scores were calculated to indicate the extent of change from baseline to follow-up.

RESULTS

Data were available on 148 patients: 72 received laser therapy and 76 received TURP. Mean change in AUA-7 score at 3 months was 7.3 in the laser arm, compared with 11.9 in the TURP arm (P < 0.05). Furthermore, substantial change was detected in both groups on the bothersome score. However, very few significant differences in SF-36 dimension scores from baseline to 3 months were detected.

CONCLUSIONS

The SF-36 at both baseline and follow-up indicated a similar level of health status as that reported in the general population. Subsequently, the measure did not improve on any dimensions. Our data support the claim of some researchers that shorter disease-specific indices are vital to the evaluation of treatment regimens in clinical trials, especially when the general health of the patients is similar to that of the population.

Is day-case prostatectomy feasible?

OBJECTIVE

To assess the possibility of discharging patients, catheter-free, on the same day that they undergo contact-laser prostatectomy.

PATIENTS AND METHODS

Ten patients underwent contact vaporization of the prostate using the SLT (Surgical Laser Technologies, Oaks, PA, USA) Nd:YAG laser with an MTRL10 6 mm tip. Patients were selected in the out-patient clinic for day-case surgery on the basis of their good general health and clinically small glands. All patients had pre-operative urodynamic assessment and were proven obstructed and stable. Contact vaporization was carried out under general anaesthesia. Both intra-operative blood loss and irrigant absorption were assessed. The follow-up at 3 and 6 months included American Urological Association (AUA-7) symptom scores and the measurement of urinary flow rates.

RESULTS

The mean operating time was 25.2 min, with a mean application of 43.05 kJ of laser energy. The mean absorption of irrigant fluid was 30 mL and the mean intra-operative blood loss was 31 mL. Nine patients were discharged on the day of treatment. Two patients went into clot retention following discharge and had a suprapubic catheter sited, and two failed to void once discharged, necessitating catheterization for 2 weeks. At 3 and 6 months, there was a substantial decrease in the AUA symptom score and an improvement in urinary flow rate.

CONCLUSION

Day-case laser prostatectomy is possible, but the patients must be selected carefully and, perhaps more importantly, a specialist day-case anaesthetist must be available.