A Three Month Home Exercise Programme Augmented with Nordic Poles for Patients with Intermittent Claudication Enhances Quality of Life and Continues to Improve Walking Distance and Compliance After One Year.

OBJECTIVE/BACKGROUND: The objective of this study was to collect 1 year follow-up information on walking distance, speed, compliance, and cost in patients with intermittent claudication who took part in a previously reported 12 week randomised clinical trial of a home exercise programme augmented with Nordic pole walking versus controls who walked normally. A second objective was to look at quality of life and ankle brachial pressure indices (ABPIs) after a 12 week augmented home exercise programme. METHODS: Thirty-two of the 38 patients who completed the original trial were followed-up after 6 and 12 months. Frequency, duration, speed, and distance of walking were recorded using diaries and pedometers. A new observational cohort of 29 patients was recruited to the same augmented home exercise programme. ABPIs, walking improvement, and quality of life questionnaire were recorded at baseline and 12 weeks (end of the programme). RESULTS: Both groups in the follow-up study continued to improve their walking distance and speed over the following year. Compliance was excellent: 98% of the augmented group were still walking with poles at both 6 and 12 months, while 74% of the control group were still walking at the same point. The augmented group increased their mean walking distance to 17.5 km by 12 months, with a mean speed of 4.2 km/hour. The control group only increased their mean walking distance from 4.2 km to 5.6 km, and speed to 3.3 km/hour. Repeated ANOVA showed the results to be highly significant (p = .002). The 21/29 patients who completed the observational study showed a statistically significant increase in resting ABPIs from baseline (mean ± SD 0.75 ± 0.12) to week 12 (mean ± SD 0.85 ± 0.12) (t = (20) -8.89, p = .000 [two-tailed]). All their walking improvement and quality of life parameters improved significantly (p = .002 or less in the six categories) over the same period and their mean health scores improved by 79%. CONCLUSIONS: Following a 12 week augmented home exercise programme, most patients with intermittent claudication continued to significantly improve their walking distance and walking speed at 1 year compared with normal walking. Quality of life and ABPIs improved significantly after only 12 weeks and it is postulated that the improvement in ABPI was due to collateral development. These results justify the belief that an augmented home exercise programme will be as clinically effective as existing supervised exercise programmes, with the added benefits of lower cost and better compliance. Funding for a multicentre trial comparing an augmented home exercise programme with existing supervised exercise programme is now urgently required.

Predicted shortage of vascular surgeons in the United Kingdom: A matter for debate?

BACKGROUND: Vascular surgery became a new independent surgical specialty in the United Kingdom (UK) in 2013. In this matter for debate we discuss the question, is there a "shortage of vascular surgeons in the United Kingdom?" MATERIALS AND METHODS: We used data derived from the "Vascular Surgery United Kingdom Workforce Survey 2014", NHS Employers Electronic Staff Records (ESR), and the National Vascular Registry (NVR) surgeon-level public report to estimate current and predict future workforce requirements. RESULTS: We estimate there are approximately 458 Consultant Vascular Surgeons for the current UK population of 63 million, or 1 per 137,000 population. In several UK Regions there are a large number of relatively small teams (3 or less) of vascular surgeons working in separate NHS Trusts in close geographical proximity. In developed countries, both the number and complexity of vascular surgery procedures (open and endovascular) per capita population is increasing, and concerns have been raised that demand cannot be met without a significant expansion in numbers of vascular surgeons. Additional workforce demand arises from the impact of population growth and changes in surgical work-patterns with respect to gender, working-life-balance and 7-day services. CONCLUSIONS: We predict a future shortage of Consultant Vascular Surgeons in the UK and recommend an increase in training numbers and an expansion in the UK Consultant Vascular Surgeon workforce to accommodate population growth, facilitate changes in work-patterns and to create safe sustainable services.

Risk Factors For Stroke, Myocardial Infarction, or Death Following Carotid Endarterectomy: Results From the International Carotid Stenting Study.

OBJECTIVES: Carotid endarterectomy (CEA) is standard treatment for symptomatic carotid artery stenosis but carries a risk of stroke, myocardial infarction (MI), or death. This study investigated risk factors for these procedural complications occurring within 30 days of endarterectomy in the International Carotid Stenting Study (ICSS). METHODS: Patients with recently symptomatic carotid stenosis >50% were randomly allocated to endarterectomy or stenting. Analysis is reported of patients in ICSS assigned to endarterectomy and limited to those in whom CEA was initiated. The occurrence of stroke, MI, or death within 30 days of the procedure was reported by investigators and adjudicated. Demographic and technical risk factors for these complications were analysed sequentially in a binomial regression analysis and subsequently in a multivariable model. RESULTS: Eight-hundred and twenty-one patients were included in the analysis. The risk of stroke, MI, or death within 30 days of CEA was 4.0%. The risk was higher in female patients (risk ratio [RR] 1.98, 95% CI 1.02-3.87, p = .05) and with increasing baseline diastolic blood pressure (dBP) (RR 1.30 per +10 mmHg, 95% CI 1.02-1.66, p = .04). Mean baseline dBP, obtained at the time of randomization in the trial, was 78 mmHg (SD 13 mmHg). In a multivariable model, only dBP remained a significant predictor. The risk was not related to the type of surgical reconstruction, anaesthetic technique, or perioperative medication regimen. Patients undergoing CEA stayed a median of 4 days before discharge, and 21.2% of events occurred on or after the day of discharge. CONCLUSIONS: Increasing diastolic blood pressure was the only independent risk factor for stroke, MI, or death following CEA. Cautious attention to blood pressure control following symptoms attributable to carotid stenosis could reduce the risks associated with subsequent CEA.

The vascular surgery workforce: a survey of consultant vascular surgeons in the UK, 2014.

OBJECTIVE: The purpose of this study was to describe the demographics, training, and practice characteristics of consultant vascular surgeons across the UK to provide an assessment of current, and inform future prediction of workforce needs. METHODS: A questionnaire was developed using a modified Delphi process to generate questionnaire items. The questionnaire was emailed to all consultant vascular surgeons (n = 450) in the UK who were members of the Vascular Society of Great Britain & Ireland. RESULTS: 352 consultant vascular surgeons from 95 hospital trusts across the UK completed the survey (78% response rate). The mean age was 50.6 years old, the majority (62%) were mid-career, but 24% were above the age of 55. Currently, 92% are men and only 8% women. 93% work full-time, with 60% working >50 hours, and 21% working >60 hours per week. The average team was 5 to 6 (range 2-10) vascular surgeons, with 23% working in a large team of ≥8. 17% still work in small teams of ≤3. Over 90% of consultant vascular surgeons perform the major index vascular surgery procedures (aneurysm repair, carotid endarterectomy, infra-inguinal bypass, amputation). While 84% perform standard endovascular abdominal aortic aneurysm repair (EVAR), <50% perform more complex endovascular aortic therapy. The majority of vascular surgeons "like their job" (85%) and are "satisfied" (69%) with their job. 34% of consultant vascular surgeons indicated they were "extremely likely" to retire within the next 10 years. CONCLUSIONS: This study provides the first detailed analysis of the new specialty of vascular surgery as practiced in the UK. There is a need to plan for a significant expansion in the consultant vascular surgeon workforce in the UK over the next 10 years to maintain the status quo.

Randomized clinical trial comparing Nordic pole walking and a standard home exercise programme in patients with intermittent claudication.

BACKGROUND: This was a randomized clinical trial to determine whether Nordic pole walking (NPW) is more effective in improving walking distance than a standard home exercise programme (HEP) in patients with intermittent claudication. METHODS: Fifty-two patients with stable claudication were allocated randomly to a standard HEP or NPW group, and asked to complete three 30-min walks per week for 12 weeks. Claudication distance (CD) and maximum walking distance (MWD) were measured at 0 (baseline), 4, 8 and 12 weeks. Patients in the NPW group were tested with (NPW+) and without (NPW-) poles. RESULTS: For NPW+, CD increased immediately from a median (range) of 124 (71-248) m to 148 (116-426) m, and MWD from 248 (149-900) to 389 (194-1099) m (P = 0.004 and P < 0.001 respectively). By 12 weeks, CD had further increased to 199 (118-550) m and MWD had more than doubled to 538 (250-1750) m (P < 0.001 and P = 0.001). For NPW-, CD at 12 weeks had increased significantly to 151 (100-328) m and MWD to 400 (200-900) m (P < 0.001 and P = 0.006 respectively). At 12 weeks the changes in the standard HEP group were not significant, despite excellent compliance: CD from 107 (56-332) to 153 (59-321) m and MWD from 355 (92-600) to 334 (149-874) m (P = 0.030 and P = 0.260 respectively). CONCLUSION: A 12-week exercise programme using Nordic poles significantly improved walking distance in claudicants compared with a standard HEP. REGISTRATION NUMBER: ISRCTN78168304 (http://www.controlled-trials.com).

Systematic review of home-based exercise programmes for individuals with intermittent claudication.

We aimed to conduct a systematic review of the evidence for structured, home-based exercise programmes (HEPs) in patients with intermittent claudication. The Medline, PsycINFO, EMBASE, and Cochrane databases were searched up to April 2013 for terms related to walking, self-management, and intermittent claudication. Descriptive, methodological and outcome data were extracted from eligible articles. Trial quality was assessed using the GRADE system. Seventeen studies were included with 1,457 participants. Six studies compared HEPs with supervised exercise training, five compared HEPs with usual care/observation control, and seven evaluated HEPs in a single-group design. Trial heterogeneity prevented meta-analysis. Nevertheless, there was "low-level" evidence that HEPs can improve walking capacity and quality of life in patients with intermittent claudication when compared with baseline or in comparison to usual care/observation control. In addition, improvements with HEPs may be inferior to those evoked by supervised exercise training. Considerable uncertainty exists regarding the long-term clinical and cost effectiveness of HEPs in patients with intermittent claudication. Thus, more robust trials are needed to build evidence about these interventions. Nevertheless, clinicians should consider using structured interventions to promote self-managed walking in patients with intermittent claudication, as opposed to simple "go home and walk" advice, when supervised exercise training is unavailable or impractical.

Randomized trial of the effect of video feedback on the acquisition of surgical skills.

BACKGROUND: Constructive feedback provides a mechanism for reinforcing learning during the acquisition of surgical skills. Feedback is usually given verbally, and sometimes documented, after direct observation by a trained assessor. The aim was to evaluate video recording as an effective modality for enhancing feedback, in comparison with standard verbal feedback alone. METHODS: This was a prospective, blinded, randomized clinical trial comparing standard verbal feedback plus video with standard verbal feedback alone. Validated pro formas for assessment were used and quality control was performed by independent expert assessors. Trial participants were recorded on video performing the surgical skill, and returned the next day to perform the skill again following video and standard verbal feedback (group 1) or standard verbal feedback alone (group 2). RESULTS: Forty-eight participants were divided equally between the two groups. There was a significant improvement in the mean overall procedure score for group 1 of 2·875 from a maximum achievable score of 20 (P = 0·003), but not for group 2. There were significant improvements in the specific domains of instrument familiarity, needle handling, skin handling and accurate apposition, again all in group 1. The only significant improvement in group 2 was in an organized approach to the task, also observed in group 1. Knot-tying security deteriorated after feedback in group 2 but not in group 1. CONCLUSION: The addition of video feedback can improve the acquisition of surgical skills, and could be incorporated into formal surgical curricula.

Systematic review and meta-analysis of duplex ultrasonography, contrast-enhanced ultrasonography or computed tomography for surveillance after endovascular aneurysm repair.

BACKGROUND: Previous analyses suggested that duplex ultrasonography (DUS) detected endoleaks after endovascular aneurysm repair (EVAR) with insufficient sensitivity; they did not specifically examine types 1 and 3 endoleak, which, if untreated, may lead to aneurysm-related death. In light of changes to clinical practice, the diagnostic accuracy of DUS and contrast-enhanced ultrasonography (CEUS) for types 1 and 3 endoleak required focused reappraisal. METHODS: Studies comparing DUS or CEUS with computed tomography (CT) for endoleak detection were identified. CT was taken as the standard in bivariable meta-analysis. RESULTS: Twenty-five studies (3975 paired scans) compared DUS with CT for all endoleaks. The pooled sensitivity was 0·74 (95 per cent confidence interval 0·62 to 0·83) and the pooled specificity was 0·94 (0·90 to 0·97). Thirteen studies (2650 paired scans) reported detection of types 1 and 3 endoleak by DUS; the pooled sensitivity of DUS was 0·83 (0·40 to 0·97) and the pooled specificity was 1·00 (0·97 to 1·00). Eleven studies (961 paired scans) compared CEUS with CT for all endoleaks. The pooled sensitivity of CEUS was 0·96 (0·85 to 0·99) and the pooled specificity was 0·85 (0·76 to 0·92). Eight studies (887 paired scans) reported detection of types 1 and 3 endoleak by CEUS. The pooled sensitivity of CEUS was 0·99 (0·25 to 1·00) and the pooled specificity was 1·00 (0·98 to 1·00). CONCLUSION: Both CEUS and DUS were specific for detection of types 1 and 3 endoleak. Estimates of their sensitivity were uncertain but there was no evidence of a clinically important difference. DUS detects types 1 and 3 endoleak with sufficient accuracy for surveillance after EVAR.

Endofibrosis and kinking of the iliac arteries in athletes: a systematic review.

INTRODUCTION: Kinking and endofibrosis of the iliac arteries are uncommon and poorly recognized conditions affecting young endurance athletes. Deformation or progressive stenosis of the iliac artery may reduce blood flow to the lower limb and adversely affect performance. The aim of this review was to examine the existing literature relating to these flow-limiting phenomena and identify a clear, unifying strategy for the assessment and management of affected patients. METHODS: A systematic review of the literature was performed. A comprehensive search was carried out using Medline, Embase and The Cochrane Database to identify relevant articles published between 1950 and 2011 (last search date 05/08/2011). This search (and additional bibliography review) identified 413 articles, of which 367 were excluded. 46 articles were then studied in detail. Methodological quality of studies was assessed according to Scottish Intercollegiate Guideline Network criteria. RESULTS: Focussed history and examination can successfully identify nearly 80% of patients with iliac flow limitation. However, both provocative exercise tests and detailed imaging are also necessary to identify those in need of intervention and establish most appropriate treatment. Provocative exercise tests and duplex imaging can then be used to confirm flow limitation before detailed assessment of abnormal anatomy with MRA and DSA. These multiple imaging modalities are necessary to identify those most likely to benefit from surgery and clarify whether each patient should undergo arterial release, vessel shortening, endofibrosectomy or interposition grafting. CONCLUSION: We present a systematic review of the literature together with a proposed algorithm for diagnosis and management of these iliac flow limitations in endurance athletes.

Retroperitoneal lymph node dissection for metastatic germ cell tumours.

INTRODUCTION: In the North Trent Cancer network (NTCN) patients requiring retroperitoneal lymphadenectomy for metastatic testicular cancer have been treated by vascular service since 1990. This paper reviews our experience and considers the case for involvement of vascular surgeons in the management of these tumours. PATIENTS AND METHODS: Patients referred by the NTCN to the vascular service for retroperitoneal lymphadenectomy between 1990 and 2009 were identified through a germ cell database. Data were supplemented by a review of case notes to record histology, intraoperative and postoperative details. RESULTS: A total of 64 patients were referred to the vascular service for retroperitoneal lymph node dissection, with a median age of 29 years (16-63 years) and a median follow-up of 4.9 years. Ten patients died: eight from tumour recurrence, one from septicaemia during chemotherapy and one by suicide. Of the 54 who survived, 7 were alive with residual masses and 47 patients were disease-free at the last follow-up. Sixteen patients required vascular procedures: four had aortic repair (fascia), three had aortic replacement (spiral graft), four had inferior vena cava resection, two had iliac artery replacement and two had iliac vein resection. CONCLUSIONS: Retroperitoneal lymph node dissection often involves mobilisation and/or the resection/replacement of major vessels. We recommend that a vascular surgeon should be a part of testicular germ cell multidisciplinary team.

Prospective observational study to evaluate NOTSS (Non-Technical Skills for Surgeons) for assessing trainees' non-technical performance in the operating theatre.

BACKGROUND: Most surgical assessment has been aimed at technical proficiency. However, non-technical skills also affect patient safety and clinical effectiveness. The NOTSS (Non-Technical Skills for Surgeons) assessment instrument was developed specifically to assess the non-technical skills of individual surgeons in the operating theatre. This study evaluated NOTSS as a real-world assessment, with a mix of minimally trained assessors. The evaluation criteria were feasibility, validity and psychometric reliability. METHODS: In a standard evaluation of NOTSS, 56 anaesthetists, 39 scrub nurses, two surgical care practitioners and three independent assessors provided 715 assessments of 404 surgical cases of 15 index procedures across six specialties performed by 85 surgical trainees. RESULTS: The assessment was feasible, but important implementation challenges were highlighted. Most respondents considered the method valid, but with reservations about assessing cognition. The factor structure of scores, and their positive relationships with other measures of experience and performance, supported validity. Trainees' non-technical skill scores were relatively procedure-independent and achieved good reliability (generalizability coefficient 0·8 or more) when six to eight assessors observed one case each. CONCLUSION: Minimally trained assessors, who are typically present in operating theatres, were sufficiently discriminating and consistent in their judgements of trainee surgeons' non-technical skills to provide reliable scores based on an achievable number of observations.

Fabrication and buckling dynamics of nanoneedle AFM probes.

A new method for the fabrication of high-aspect-ratio probes by electron beam induced deposition is described. This technique allows the fabrication of cylindrical 'nanoneedle' structures on the atomic force microscope (AFM) probe tip which can be used for accurate imaging of surfaces with high steep features. Scanning electron microscope (SEM) imaging showed that needles with diameters in the range of 18-100 nm could be obtained by this technique. The needles were shown to undergo buckling deformation under large tip-sample forces. The deformation was observed to recover elastically under vertical deformations of up to ∼ 60% of the needle length, preventing damage to the needle. A technique of stabilizing the needle against buckling by coating it with additional electron beam deposited carbon was also investigated; it was shown that coated needles of 75 nm or greater total diameter did not buckle even under tip-sample forces of ∼ 1.5 µN.

Impact of reduction in working hours for doctors in training on postgraduate medical education and patients' outcomes: systematic review.

OBJECTIVES: To determine whether a reduction in working hours of doctors in postgraduate medical training has had an effect on objective measures of medical education and clinical outcome. DESIGN: Systematic review. DATA SOURCES: Medline, Embase, ISI Web of Science, Google Scholar, ERIC, and SIGLE were searched without language restriction for articles published between 1990 and December 2010. Reference lists and citations of selected articles. STUDY SELECTION: Studies that assessed the impact of a change in duty hours using any objective measure of outcome related to postgraduate medical training, patient safety, or clinical outcome. Any study design was eligible for inclusion. RESULTS: 72 studies were eligible for inclusion: 38 reporting training outcomes, 31 reporting outcomes in patients, and three reporting both. A reduction in working hours from greater than 80 hours a week (in accordance with US recommendations) does not seem to have adversely affected patient safety and has had limited effect on postgraduate training. Reports on the impact of European legislation limiting working hours to less than 56 or 48 a week are of poor quality and have conflicting results, meaning that firm conclusions cannot be made. CONCLUSIONS: Reducing working hours to less than 80 a week has not adversely affected outcomes in patient or postgraduate training in the US. The impact of reducing hours to less than 56 or 48 a week in the UK has not yet been sufficiently evaluated in high quality studies. Further work is required, particularly in the European Union, using large multicentre evaluations of the impact of duty hours' legislation on objective educational and clinical outcomes.

Evaluation of procedure-based assessment for assessing trainees' skills in the operating theatre.

BACKGROUND: Procedure-based assessment (PBA) is used within most UK surgical training programmes for assessing trainees' procedural skills in the operating theatre. All postgraduate assessment methods require evidence to support their implementation. The aims were to evaluate the validity, reliability and acceptability of PBA. METHODS: Eighty-one trainees in six surgical specialties were assessed performing common procedures; 749 PBAs were provided across 348 operations by 57 clinical supervisors and four independent assessors. RESULTS: Construct validity was demonstrated by correlation of PBA scores with measures of surgical training and experience. Reliability (G exceeding 0·8) of the adjusted total item score and global summary score for a given procedure was achieved using four and three assessor judgements respectively; assessing a mix of procedures required more cases/assessors because performance is procedure specific. The acceptability of PBA for assessment and feedback within surgical training was predominantly positive among clinical supervisors and trainees. CONCLUSION: PBA demonstrated good overall validity and acceptability, and exceptionally high reliability. Trainees should be assessed adequately for each given procedure.

Assessing the surgical skills of trainees in the operating theatre: a prospective observational study of the methodology.

OBJECTIVES: To compare user satisfaction and acceptability, reliability and validity of three different methods of assessing the surgical skills of trainees by direct observation in the operating theatre across a range of different surgical specialties and index procedures. DESIGN AND SETTING: A 2-year prospective, observational study in the operating theatres of three teaching hospitals in Sheffield. METHODS: The assessment methods were procedure-based assessment (PBA), Objective Structured Assessment of Technical Skills (OSATS) and Non-technical Skills for Surgeons (NOTSS). The specialties were obstetrics and gynaecology (O&G) and upper gastrointestinal, colorectal, cardiac, vascular and orthopaedic surgery. Two to four typical index procedures were selected from each specialty. Surgical trainees were directly observed performing typical index procedures and assessed using a combination of two of the three methods (OSATS or PBA and NOTSS for O&G, PBA and NOTSS for the other specialties) by the consultant clinical supervisor for the case and the anaesthetist and/or scrub nurse, as well as one or more independent assessors from the research team. OUTCOME MEASURES: Information on user satisfaction and acceptability of each assessment method from both assessor and trainee perspectives was obtained from structured questionnaires. The reliability of each method was measured using generalisability theory. Aspects of validity included the internal structure of each tool and correlation between tools, construct validity, predictive validity, interprocedural differences, the effect of assessor designation and the effect of assessment on performance. RESULTS: Of the 558 patients who were consented, a total of 437 (78%) cases were included in the study: 51 consultant clinical supervisors, 56 anaesthetists, 39 nurses, 2 surgical care practitioners and 4 independent assessors provided 1635 assessments on 85 trainees undertaking the 437 cases. A total of 749 PBAs, 695 NOTSS and 191 OSATSs were performed. Non-O&G clinical supervisors and trainees provided mixed, but predominantly positive, responses about a range of applications of PBA. Most felt that PBA was important in surgical education, and would use it again in the future and did not feel that it added time to the operating list. The overall satisfaction of O&G clinical supervisors and trainees with OSATS was not as high, and a majority of those who used both preferred PBA. A majority of anaesthetists and nurses felt that NOTSS allowed them to rate interpersonal skills (communication, teamwork and leadership) more easily than cognitive skills (situation awareness and decision-making), that it had formative value and that it was a valuable adjunct to the assessment of technical skills. PBA demonstrated high reliability (G > 0.8 for only three assessor judgements on the same index procedure). OSATS had lower reliability (G > 0.8 for five assessor judgements on the same index procedure). Both were less reliable on a mix of procedures because of strong procedure-specific factors. A direct comparison of PBA between O&G and non-O&G cases showed a striking difference in reliability. Within O&G, a good level of reliability (G > 0.8) could not be obtained using a feasible number of assessments. Conversely, the reliability within non-O&G cases was exceptionally high, with only two assessor judgements being required. The reasons for this difference probably include the more summative purpose of assessment in O&G and the much higher proportion of O&G trainees in this study with training concerns (42% vs 4%). The reliability of NOTSS was lower than that for PBA. Reliability for the same procedure (G > 0.8) required six assessor judgements. However, as procedure-specific factors exerted a lesser influence on NOTSS, reliability on a mix of procedures could be achieved using only eight assessor judgements. NOTSS also demonstrated a valid internal structure. The strongest correlations between NOTSS and PBA or OSATS were in the 'decision-making' domain. PBA and NOTSS showed better construct validity than OSATS, the year of training and the number of recent index procedures performed being significant independent predictors of performance. There was little variation in scoring between different procedures or different designations of assessor. CONCLUSIONS: The results suggest that PBA is a reliable and acceptable method of assessing surgical skills, with good construct validity. Specialties that use OSATS may wish to consider changing the design or switching to PBA. Whatever workplace-based assessment method is used, the purpose, timing and frequency of assessment require detailed guidance. NOTSS is a promising tool for the assessment of non-technical skills, and surgical specialties may wish to consider its inclusion in their assessment framework. Further research is required into the use of health-care professionals other than consultant surgeons to assess trainees, the relationship between performance and experience, the educational impact of assessment and the additional value of video recording.

Large flexibility of high aspect ratio carbon nanostructures fabricated by electron-beam-induced deposition.

The mechanical properties of free-standing electron beam deposited amorphous carbon structures have been studied using atomic force microscopy. The fabricated carbon blades are found to be extraordinarily flexible, capable of undergoing vertical deflection up to ∼ 75% of their total length without inelastic deformation. The elastic bending modulus of these structures was calculated to be 28 ± 10 GPa.

An atomic force microscope nanoscalpel for nanolithography and biological applications.

We present the fabrication of specialized nanotools, termed nanoscalpels, and their application for nanolithography and nanomechanical manipulation of biological objects. Fabricated nanoscalpels have the shape of a thin blade with the controlled thickness of 20-30 nm and width of 100-200 nm. They were fabricated using electron beam induced deposition at the apex of atomic force microscope probes and are hard enough for a single cut to penetrate a approximately 45 nm thick gold layer; and thus can be used for making narrow electrode gaps required for fabrication of nanoelectronic devices. As an atomic force microscope-based technique the nanoscalpel provides simultaneous control of the applied cutting force and the depth of the cut. Using mammalian cells as an example, we demonstrated their ability to make narrow incisions and measurements of local elastic and inelastic characteristics of a cell, making nanoscalpels also useful as a nanosurgical tool in cell biology. Therefore, we believe that the nanoscalpel could serve as an important tool for nanofabrication and nanosurgery on biological objects.