Review of in vitro mechanical testing for intervertebral disc injectable biomaterials.

Many early stage interventions for intervertebral disc degeneration are under development involving injection of a biomaterial into the affected tissue. Due to the complex mechanical behaviour of the intervertebral disc, there are challenges in comprehensively evaluating the performance of these injectable biomaterials in vitro. The aim of this review was to examine the different methods that have been developed to mechanically test injectable intervertebral disc biomaterials in an in vitro disc model. Testing methods were examined with emphasis on overall protocol, artificial degeneration method, mechanical testing regimes and injection delivery. Specifically, the effects of these factors on the evaluation of different aspects of device performance was assessed. Broad testing protocols varied between studies and enabled evaluation of different aspects of an injectable treatment. Studies employed artificial degeneration methodologies which were either on a macro scale through mechanical means or on a microscale with biochemical means. Mechanical loading regimes differed greatly across studies, with load being either held constant, ramped to failure, or applied cyclically, with large variability on all loading parameters. Evaluation of the risk of herniation was possible by utilising ramped loading, whereas cyclic loading enabled the examination of the restoration of mechanical behaviour for initial screening of biomaterials and surgical technique optimisation studies. However, there are large variations in the duration or tests, and further work is needed to define an appropriate number of cycles to standardise this type of testing. Biomaterial delivery was controlled by set volume or haptic feedback, and future investigations should generate evidence applying physiological loading during injection and normalisation of injection parameters based on disc size. Based on the reviewed articles and considering clinical risks, a series of recommendations have been made for future intervertebral disc mechanical testing.

Outcomes for Patients with apparent Chronic Idiopathic Pelvic Pain and associated Pelvic Floor Disorders undergoing Laparoscopic Ventral Mesh Rectopexy.

This article has been temporarily withdrawn, with the agreement of all authors and the journal editor, whilst an investigated is being carried out by the North Bristol NHS Trust and the General Medical Council following some concerns raised.

Quantum key distribution with hacking countermeasures and long term field trial.

Quantum key distribution's (QKD's) central and unique claim is information theoretic security. However there is an increasing understanding that the security of a QKD system relies not only on theoretical security proofs, but also on how closely the physical system matches the theoretical models and prevents attacks due to discrepancies. These side channel or hacking attacks exploit physical devices which do not necessarily behave precisely as the theory expects. As such there is a need for QKD systems to be demonstrated to provide security both in the theoretical and physical implementation. We report here a QKD system designed with this goal in mind, providing a more resilient target against possible hacking attacks including Trojan horse, detector blinding, phase randomisation and photon number splitting attacks. The QKD system was installed into a 45 km link of a metropolitan telecom network for a 2.5 month period, during which time the system operated continuously and distributed 1.33 Tbits of secure key data with a stable secure key rate over 200 kbit/s. In addition security is demonstrated against coherent attacks that are more general than the collective class of attacks usually considered.

ECSPECT prospective multicentre registry for single-port laparoscopic colorectal procedures.

BACKGROUND: The international multicentre registry ECSPECT (European Consensus of Single Port Expertise in Colorectal Treatment) was established to evaluate the general feasibility and safety of single-port colorectal surgery with regard to preoperative risk assessment. METHODS: Consecutive patients undergoing single-port colorectal surgery were enrolled from 11 European centres between March 2010 and March 2014. Data were analysed to assess patient-, technique- and procedure-dependent parameters. A validated sex-adjusted risk chart was developed for prediction of single-port colorectal surgery-related conversion and complications. RESULTS: Some 1769 patients were enrolled, 937 with benign and 832 with malignant conditions. Procedures were completed without additional trocars in 1628 patients (92·0 per cent). Conversion to open surgery was required in 75 patients (4·2 per cent) and was related to male sex and ASA fitness grade exceeding I. Conversions were more frequent in pelvic procedures involving the rectum compared with abdominal procedures (8·1 versus 3·2 per cent; odds ratio 2·69, P < 0·001). Postoperative complications were observed in a total of 224 patients (12·7 per cent). Independent predictors of complications included male sex (P < 0·001), higher ASA grade (P = 0·006) and rectal procedures (P = 0·002). The overall 30-day mortality rate was 0·5 per cent (8 of 1769 patients); three deaths (0·2 per cent; 1 blood loss, 2 leaks) were attributable to surgical causes. CONCLUSION: The feasibility and safety, conversion and complication profile demonstrated here provides guidance for patient selection.

High speed prototype quantum key distribution system and long term field trial.

Securing information in communication networks is an important challenge in today's world. Quantum Key Distribution (QKD) can provide unique capabilities towards achieving this security, allowing intrusions to be detected and information leakage avoided. We report here a record high bit rate prototype QKD system providing a total of 878 Gbit of secure key data over a 34 day period corresponding to a sustained key rate of around 300 kbit/s. The system was deployed over a standard 45 km link of an installed metropolitan telecommunication fibre network in central Tokyo. The prototype QKD system is compact, robust and automatically stabilised, enabling key distribution during diverse weather conditions. The security analysis includes an efficient protocol, finite key size effects and decoy states, with a quantified key failure probability of ε = 10⁻¹°.

High speed and adaptable error correction for megabit/s rate quantum key distribution.

Quantum Key Distribution is moving from its theoretical foundation of unconditional security to rapidly approaching real world installations. A significant part of this move is the orders of magnitude increases in the rate at which secure key bits are distributed. However, these advances have mostly been confined to the physical hardware stage of QKD, with software post-processing often being unable to support the high raw bit rates. In a complete implementation this leads to a bottleneck limiting the final secure key rate of the system unnecessarily. Here we report details of equally high rate error correction which is further adaptable to maximise the secure key rate under a range of different operating conditions. The error correction is implemented both in CPU and GPU using a bi-directional LDPC approach and can provide 90-94% of the ideal secure key rate over all fibre distances from 0-80 km.

Laparoscopic ventral mesh rectopexy in male patients with internal or external rectal prolapse.

AIM: Laparoscopic ventral mesh rectopexy (LVMR) has been used to treat rectal prolapse, obstructed defaecation (OD), faecal incontinence (FI) and multicompartment pelvic floor dysfunction. Its value in treating men has been questioned. The aim of the present study was to assess the results in male patients. METHOD: A password-protected electronic database of all LVMRs carried out in North Bristol NHS trust & Spire hospital between 2002 and 2013 was examined. In addition to the clinical outcome, quality of life (QoL), Cleveland Clinic Incontinence Score (CCIS), obstructed defecation syndrome (ODS) score, visual analogue score (VAS) for the severity of bowel and urinary symptoms and the numerical rating scale (NRS) for pain and patient-reported outcome measures were evaluated. RESULTS: Sixty-eight men of median age 35 years and body mass index 26 kg/m(2) underwent LVMR for external rectal prolapse (18) or Grade III-V rectal intussusception (50) presenting with OD, FI and pelvic pain. Ten per cent had been labelled 'chronic idiopathic pelvic pain' and 60% had undergone previous haemorrhoidal surgery. Complications were minor and included urinary retention (10%). Eighty per cent of patients had an uncomplicated recovery with 24% being treated as day cases. There were no cases of impotence or retrograde ejaculation. Median follow-up was 42 (IQR 26-61) months. CCIS score improved from 4 (IQR 0-8) to 0 (IQR 0-0) (P < 0.001) and the ODS score from 18.5 (IQR 16-22) to 6 (IQR 5-8) (P < 0.001). Patients reported significant improvement in the NRS for pain and QoL (BBSQ-22) at 3 months (P = 0.000). The QoL and the VAS for bowel symptoms were maintained at 4 years. At the last follow-up 56 (82%) patients were asymptomatic and 6 (8.8%) had persisting symptoms. There was no case of recurrent external rectal prolapse. CONCLUSION: LVMR is an effective treatment for external and symptomatic internal rectal prolapse in men, leading to significant improvement in QoL and function.

Outcome of laparoscopic ventral mesh rectopexy for external rectal prolapse.

AIM: The study assessed the efficacy of laparoscopic ventral mesh rectopexy (LVMR) for full thickness external rectal prolapse (ERP), including recurrent prolapse. METHOD: A prospective database identified all patients undergoing LVMR for ERP over the 16-year period to December 2013. Clinical outcome, Cleveland Clinic Incontinence Score (CCIS), quality of life (QOL) and patient-reported outcome were evaluated. RESULTS: In total, 190 LVMRs (87% women) were performed during the study period, with a median active follow-up of 29 (1-196) months; 120 had a follow-up > 5 years and 16 > 10 years. The median time from surgery was 73 (1-196) months. The 60-day mortality, recurrence and mesh-related complication rates were 1%, 3% and 3.7%. The mean improvement in CCIS was 8 (P < 0.0001). Sixty-two patients returned a complete sequence of QOL scores (Birmingham Bowel and Urinary Symptoms Questionnaire 22), which had improved by 46% at year 1 and were sustained at a median of 4 years (P < 0.001). Mean patient-reported outcome measures for satisfaction at final review in 119 responders was 9.1/10. Thirty-nine patients underwent LVMR for recurrent ERP following perineal repair. Of these, full thickness recurrence occurred in one and there were no mesh complications. The same sustained improvement in QOL was observed. CONCLUSION: LVMR for ERP is associated with low morbidity and recurrence and a long-term improvement in function and QOL. LVMR achieves the same benefits after a failed perineal procedure.

Efficient decoy-state quantum key distribution with quantified security.

We analyse the finite-size security of the efficient Bennett-Brassard 1984 protocol implemented with decoy states and apply the results to a gigahertz-clocked quantum key distribution system. Despite the enhanced security level, the obtained secure key rates are the highest reported so far at all fibre distances.

How to deal with complications after laparoscopic ventral mesh rectopexy: lessons learnt from a tertiary referral centre.

AIM: Laparoscopic ventral mesh rectopexy (LVMR) is increasingly recognized as having utility in rectal prolapse, obstructive defaecation syndrome (ODS), faecal incontinence (FI) and multicompartment pelvic floor dysfunction (PFD). This study aimed to highlight gaps in service provision and areas for improvement by examining a cohort of patients with complications referred to a tertiary centre. METHOD: Examination was carried out of a password-protected electronic database of all LVMRs operated on in one institution. RESULTS: Fifty patients (45 women), median age 54 (range, 24-71) years, were referred with early symptomatic failure (n = 27) following an inadequate LVMR or major mesh complications (erosion into another organ, fistulation or stricturing) (n = 23). All were amenable to remedial laparoscopic surgery. Functional improvements were found in pre- and postoperative ODS, Wexner (FI) scores (two-tailed t-test; P < 0.0001) and quality of life (Birmingham Bowel and Urinary Symptoms Questionnaire-22) scores at 3 months (two-tailed t-test; P < 0.001) and normalization at 1 year (P < 0.015). This was mirrored by improved linear bowel symptom severity visual analogue scale scores (two-tailed t-test; P < 0.0001 at 3 months and P = 0.015 at 1 year) . CONCLUSION: LVMR can be associated with technical complications arising from inadequate technique or from operation-specific complications that are amenable to complex revisional laparoscopic surgery with significant improvement in quality of life and function.

Laparoscopic ventral mesh rectopexy in the management of solitary rectal ulcer syndrome: a cause for optimism?

AIM: The treatment of solitary rectal ulcer syndrome (SRUS) is notoriously difficult. Laparoscopic ventral mesh rectopexy (LVMR) is a nonresectional technique for patients with full thickness external rectal prolapse and internal prolapse with obstructed defaecation syndrome (ODS), features associated in the pathogenesis of SRUS. Our aim was to assess the short- and long-term efficacy of LVMR in treating SRUS. METHOD: Forty-eight patients with SRUS who underwent LVMR over a 15-year period (December 1996 to July 2012) were identified from a prospectively maintained electronic database. RESULTS: Forty-eight patients, 38 (79%) women, median age 43 (18-80) years, median body mass index 26 (21-40) kg/m(2) underwent LVMR for SRUS after initial biofeedback. The median follow-up was 33 months (95% CI 31-55, range 1-186 months); 52% were followed for more than 3 years and 13 (27%) for more than 5 years. Five (10%) had relapsed following a response to stapled transanal rectal resection (STARR; 10 additional patients have had a continued response to STARR). Eleven (23%) had intermittent reducible external prolapse. Epithelial ulcer healing was reported in all patients at 3 months. The ODS scores improved by 68% (P < 0.0001) and quality of life (QoL; Birmingham Bowel and Urinary Symptoms Questionnaire-22) scores improved by 45% (P < 0.0001). There was a significant improvement in bowel visual analogue scale (VAS) scores at 3 and 12 months (P = 0.0007). Sustained improvement in QoL and VAS scores was maintained at 2 years and continued in the 52% followed up for between 3 and 15 years. There were four (8%) symptomatic ODS recurrences: posterior rectal wall prolapse successfully treated by STARR (3) and one symptom free for 2 years following a temporary loop ileostomy. There were two recurrences (4%). CONCLUSION: LVMR appears to provide a sustained improvement in QoL, VAS and patient satisfaction in patients with SRUS. Morbidity, recurrence and safety profiles are low.

Comparison of single-incision laparoscopic high anterior resection with standard laparoscopic high anterior resection.

AIM: Single-incision laparoscopic surgery (SILS) is gaining momentum. The aim of the present study was to compare the outcome of SILS for high anterior resection with that of standard laparoscopic resection (StdLS). METHOD: Patients undergoing laparoscopic high anterior resection were prospectively entered into an institutional approved database. Patients treated with SILS were compared with those undergoing StdLS. RESULTS: Between April 2000 and April 2009, 327 (143 cancer) consecutive unselected patients underwent StdLS; there were three (1%) conversions and 12 (3.6%) covering ileostomies. After April 2009, 55 (29 cancer) consecutive, unselected patients underwent SILS; there were two conversions to a three-port technique (3.6%), no conversions to open resection and two (3.6%) covering ileostomies. There were no significant differences in age, sex, body mass index, hospital of operation or American Society of Anesthesiology (ASA) grade between the two groups. The operating time for SILS was significantly shorter (113 ± 44 min for StdLS vs 79 ± 37 min for SILS; P < 0.0001). SILS patients tolerated a normal diet earlier [10 (2-24) h for SILS vs 18 (2-96) h for StdLS] and were discharged faster [1 (1-8) days for SILS vs 3 (1-24) days for StdLS]. There were no significant differences in return to theatre, readmissions or 30-day mortality. CONCLUSION: SILS for high anterior resection is feasible, safe and quicker to perform than standard three-port laparoscopic colectomy. It seems to be associated with a faster recovery and earlier discharge.

Enhanced recovery after laparoscopic colorectal resection with primary anastomosis: accelerated discharge is safe and does not give rise to increased readmission rates.

AIMS: Enhanced recovery programmes after colorectal surgery are promoted to minimize complications and expedite recovery, thus reducing length of hospital stay where appropriate and improving the overall standard of patient care. There are few published trials of enhanced recovery programmes in the context of laparoscopic colorectal surgery. METHODS: Data were prospectively collected on all laparoscopic colorectal resections carried out in our institution from May 2004 to November 2009. An informal move to 48-h discharge was introduced in May 2004 and the official enhanced recovery programme was launched in November 2008. We identified all patients with a primary anastomosis discharged within 3 days of surgery. Early outcomes - leaks, complications, readmission rates and returns to theatre - were analysed. RESULTS: In all, 606 resections were performed in this period. Median length of stay was 4 (0-52) days. Of these patients, 279 (46%) met the criteria of accelerated discharge by day 3: 2 (0.7%) were discharged on the day of surgery, 70 (25.1%) within 24 h, 116 (41.6%) within 48 h and 91 (32.6%) by 72h. Age was not a significant factor in determining length of stay. Patients undergoing right hemicolectomy were more likely to be discharged by 24 h than those with left-sided anastomoses, and patients having total mesorectal excision resections were more likely to stay 3 days. The readmission rate was 4%, regardless of day of discharge. CONCLUSION: Accelerated discharge is feasible and safe. High readmission rates reported in enhanced recovery programmes after open colorectal surgery have not occurred in our laparoscopic experience.

Short-term outcome following elective laparoscopic colorectal cancer resection in octogenarians and nonagenarians.

AIM: The 30-day outcome after laparoscopic resection for cancer in patients over the age of 80 years was studied. METHOD: An electronic database was used to identify patients over 80 years who underwent laparoscopic bowel resection between December 2000 and October 2009 at three UK laparoscopic colorectal training units. Patients who required abdominoperineal excision of the rectum were excluded. RESULTS: In all, 173 patients (80 men) of median age 84 (80-93) years were identified. American Society of Anesthesiologists (ASA) grades were ASA 1, 14; ASA 2, 87; ASA 3, 68; and ASA 4, 4. Median body mass index was 26 (14-45) kg/m(2). Thirteen (7.5%) patients were converted to open surgery. The major causes for conversion were bleeding and adhesions. Thirty-three major complications occurred in 21 (12%) patients. Ten (5.8%) required readmission after discharge for complications giving a total of 17.8% of patients with complications. The median hospital stay was 5 (1-37) days. Three (1.7%) patients died within 30 days of surgery. CONCLUSION: This study confirms that laparoscopic large bowel resection is safe and beneficial in a population over 80 years. It has low morbidity and mortality and a shortened hospital stay. Octogenarians should not be denied major laparoscopic bowel surgery based on age alone.

Laparoscopic total mesorectal excision can be performed on a nonselective basis in patients with rectal cancer with excellent medium-term results.

AIM: Concerns exist regarding laparoscopic rectal cancer surgery due to increased rates of open conversion, complications and circumferential resection margin positivity. This study reports medium-term results from consecutive unselected cases in a single surgeon series. METHOD: The results of laparoscopic total mesorectal excision (TME) for rectal cancer over a 9-year period within the context of an evolving 'enhanced recovery protocol' (ERP) were reviewed from analysis of a prospectively maintained database. RESULTS: One hundred and fifty patients (91 male, median age 69 years, median BMI 26) underwent laparoscopic TME over 9 years. Median follow up was 28.5 months (range 0-88). Sixteen (10.6%) patients underwent neoadjuvant radiotherapy. Six (4.0%) required open conversion and 13 (9.0%) had an anastomotic leakage. The proportion of Dukes stages were: A, 33.3%; B, 30.7%; C, 31.3%; D, 4.7%. Five (3.3%) patients had an R1 and one an R2 resection. Median length of postoperative stay was 6 days. Three (2.0%) patients died within 30 days. Four (2.7%) developed local recurrence and 14 (9.3%) developed distant metastases. Predicted 5-year disease-free and overall survival rates by Kaplan-Meier analysis were 85.8% and 78.7%, respectively. CONCLUSION: Laparoscopic TME surgery can safely be offered to unselected patients with rectal cancer with excellent medium-term results.

Single incision laparoscopic (SILS) restorative proctocolectomy with ileal pouch-anal anastomosis.

BACKGROUND: Restorative proctocolectomy with ileoanal pouch is the definitive procedure in ulcerative colitis. The potential benefits afforded by a single incision laparoscopic (SILS) approach make it appropriate to consider. METHODS: Electronic data were prospectively collected from all patients who underwent SILS restorative proctocolectomy (SILS-RPC) between June 2009 and June 2010. RESULTS: Ten consecutive patients (4 male), with median BMI = 22 (range = 20-28 kg/m(2)) underwent SILS-LRPC over a 1-year period. Three had undergone a previous emergency laparoscopic colectomy. A single-port device (Covidien SILS™ or Olympus TriPort™) was positioned at the site of the existing or proposed temporary ileostomy (2.5-cm incision). The colon and rectum were extracted through the SILS site (n = 8) or transanally following a mucosectomy (n = 2). A 20-cm J pouch was constructed extracorporeally and returned via the ileostomy site. Pouch-anal anastomosis was performed intracorporeally (n = 8) or hand-sutured (n = 2) and a diverting loop ileostomy was created at the SILS port site. The median operation time was 185 min (range = 100-381). There were no conversions or additional ports required. Median time to full diet was 36 h (range = 4-48 h) with a median hospital stay of 3 days (range = 2-8 days). There were no 30-day readmissions. Complications included surgical emphysema with temperature and a panic attack. Nine stomas have been closed. All patients have spontaneity of defecation, with a median pouch frequency of four per day, including once at night. All are fully continent and able to defer during the day. One reported a dry ejaculate for 10 weeks. CONCLUSION: SILS restorative proctocolectomy is safe with good early functional outcomes when performed by an experienced laparoscopic surgeon.

Field test of quantum key distribution in the Tokyo QKD Network.

A secure communication network with quantum key distribution in a metropolitan area is reported. Six different QKD systems are integrated into a mesh-type network. GHz-clocked QKD links enable us to demonstrate the world-first secure TV conferencing over a distance of 45km. The network includes a commercial QKD product for long-term stable operation, and application interface to secure mobile phones. Detection of an eavesdropper, rerouting into a secure path, and key relay via trusted nodes are demonstrated in this network.