Peripheral artery disease causes consistent gait irregularities regardless of the location of leg claudication pain

BACKGROUND

The most common symptom of peripheral artery disease (PAD) is intermittent claudication that involves the calf, thigh, and/or buttock muscles. How the specific location of this leg pain is related to altered gait, however, is unknown.

OBJECTIVES

We hypothesized that because the location of claudication symptoms uniquely affects different leg muscle groups in people with PAD, this would produce distinctive walking patterns.

METHODS

A total of 105 participants with PAD and 35 age-matched older volunteers without PAD (CTRL) were recruited. Participants completed walking impairment questionnaires (WIQ), Gardner-Skinner progressive treadmill tests, the six-minute walk test, and we performed an advanced evaluation of the biomechanics of their overground walking. Participants with PAD were categorized into 4 groups according to their stated pain location(s): calf only (C, n = 43); thigh and calf (TC, n = 18); buttock and calf (BC, n = 15); or buttock, thigh, and calf (BTC, n = 29). Outcomes were compared between CTRL, C, TC, BC and BTC groups using a one-way ANOVA with post-hoc comparisons to identify and assess statistically significant differences.

RESULTS

There were no significant differences between CTRL, C, TC, BC and BTC groups in distances walked or walking speed when either pain-free or experiencing claudication pain. Each participant with PAD had significantly dysfunctional biomechanical gait parameters, even when pain-free, when compared to CTRL (pain-free) walking data. During pain-free walking, out of the 18 gait parameters evaluated, we only identified significant differences in hip power generation during push-off (in C and TC groups) and in knee power absorption during weight acceptance (in TC and BC groups). There were no between-group differences in gait parameters while people with PAD were walking with claudication pain.

CONCLUSIONS

Our data demonstrate that PAD affects the ischemic lower extremities in a diffuse manner irrespective of the location of claudication symptoms.

DATABASE REGISTRATION

ClinicalTrials.gov NCT01970332.

Peripheral artery disease affects the function of the legs of claudicating patients in a diffuse manner irrespective of the segment of the arterial tree primarily involved

Different levels of arterial occlusive disease (aortoiliac, femoropopliteal, multi-level disease) can produce claudication symptoms in different leg muscle groups (buttocks, thighs, calves) in patients with peripheral artery disease (PAD). We tested the hypothesis that different locations of occlusive disease uniquely affect the muscles of PAD legs and produce distinctive patterns in the way claudicating patients walk. Ninety-seven PAD patients and 35 healthy controls were recruited. PAD patients were categorized to aortoiliac, femoropopliteal and multi-level disease groups using computerized tomographic angiography. Subjects performed walking trials both pain-free and during claudication pain and joint kinematics, kinetics, and spatiotemporal parameters were calculated to evaluate the net contribution of the calf, thigh and buttock muscles. PAD patients with occlusive disease affecting different segments of the arterial tree (aortoiliac, femoropopliteal, multi-level disease) presented with symptoms affecting different muscle groups of the lower extremity (calves, thighs and buttocks alone or in combination). However, no significant biomechanical differences were found between PAD groups during the pain-free conditions with minimal differences between PAD groups in the claudicating state. All statistical differences in the pain-free condition occurred between healthy controls and one or more PAD groups. A discriminant analysis function was able to adequately predict if a subject was a control with over 70% accuracy, but the function was unable to differentiate between PAD groups. In-depth gait analyses of claudicating PAD patients indicate that different locations of arterial disease produce claudication symptoms that affect different muscle groups across the lower extremity but impact the function of the leg muscles in a diffuse manner generating similar walking impairments.

Evidence-based Prevention of Surgical Site Infection

Surgical site infection (SSI) remains an important complication of surgery. SSI is estimated to affect 2% to 5% of all surgical patients. Local and national efforts have resulted in significant improvements in the incidence of SSI. Familiarity with evidence surrounding high-quality SSI-reduction strategies is desirable. There exists strong evidence for mechanical and oral antibiotic bowel preparation in colorectal surgery, smoking cessation before elective surgery, prophylactic antibiotics, chlorhexidine-based skin antisepsis, and maintenance of normothermia throughout the perioperative period to reduce SSI. Use of other practices should be determined by the operating surgeon and/or local hospital policy.

Less is more: creation and validation of a novel, affordable suturing simulator for anorectal surgery

BACKGROUND

Duty hour restrictions have increased the role of simulation in surgical education. A simulation that recreates the unique visual, anatomic, and ergonomic challenges of anorectal surgery has yet to be described. The aim of this study was to develop a low-cost, low-fidelity anorectal surgery simulator and provide validity evidence for the model.

METHODS

A novel, low-fidelity simulator was constructed, and anorectal surgery workshops were implemented for general surgery interns at a single institution. Face and content validity were assessed with separate questionnaires using a 5-point Likert scale. Participants performed a simulated hemorrhoid excision with longitudinal wound closure, and transverse wound closure. Time-to-task completion and quality of suturing/knot tying were evaluated by a blinded observer to assess construct validity.

RESULTS

Material cost was US $11 per simulator. We recruited 20 first-year surgery residents (novices) and 4 practicing colorectal surgeons (experts), and conducted 3 workshops in 2014-2016. All face and content validity measures achieved a median score greater than 4 (range 4.0-5.0). Time-to-task completion was significantly lower in the expert cohort (hemorrhoid excision with longitudinal wound closure: 195 vs. 477 s and transverse closure: 79 vs. 192 s, p < 0.001 for both). Suturing and knot-tying scores were significantly higher in the expert cohort for both tasks (p < 0.05 for all comparisons).

CONCLUSIONS

Our low-fidelity, low-cost anorectal surgery model demonstrated evidence of face, content, and construct validity. We believe that this simulator could be a useful instrument in the education of junior surgical trainees and will allow residents to obtain proficiency in anorectal suturing tasks in conjunction with traditional surgical training.

Inflammatory Bowel Disease and Short Bowel Syndrome

Short bowel syndrome / intestinal failure (SBS/IF) is a rare and debilitating disease process that mandates a multidisciplinary approach in its management. Inflammatory bowel disease (IBD), in particular Crohn's disease (CD), predisposes patients to development of SBS/IF. This review discusses SBS/IF from the perspective of IBD, with an emphasis on prevention and treatment in the setting of CD. The aims of this review are to emphasize the unique treatment goals of the newly diagnosed SBS/IF patient, and highlight the role of both medical and surgical therapies in the management of IBD-related SBS/IF, including intestinal transplantation.

A low-cost, wireless near-infrared spectroscopy device detects the presence of lower extremity atherosclerosis as measured by computed tomographic angiography and characterizes walking impairment in peripheral artery disease

BACKGROUND

Patients with peripheral artery disease (PAD) who experience intermittent claudication report a range of symptoms. Patients with symptoms other than classically described intermittent claudication may be at the highest risk for functional decline and mobility loss. Therefore, technologies allowing for characterization of PAD severity are desirable. Near-infrared spectroscopy (NIRS) allows for measurements of muscle heme oxygen saturation (StO₂) during exercise. We hypothesized lower extremities affected by PAD would exhibit distinct NIRS profiles as measured by a low-cost, wireless NIRS device and that NIRS during exercise predicts walking limitation.

METHODS

We recruited 40 patients with PAD and 10 control participants. All patients with PAD completed a computed tomographic angiography, 6-minute walk test, and a standardized treadmill test. Controls completed a 540-second treadmill test for comparison. StO₂ measurements were continuously taken from the gastrocnemius during exercise. Variables were analyzed by Fischer's exact, χ², Wilcoxon rank-sum, and Kruskal-Wallis tests as appropriate. Correlations were assessed by partial Spearman correlation coefficients adjusted for occlusive disease pattern.

RESULTS

Patients with PAD experienced claudication onset at a median of 108 seconds with a median peak walking time of 288 seconds. The baseline StO₂ was similar between PAD and control. The StO₂ of PAD and control participants dropped below baseline at a median of 1 and 104 seconds of exercise, respectively (P < .0001). Patients with PAD reached minimum StO₂ earlier than control participants (119 seconds vs 522 seconds, respectively; P < .001) and experienced a greater change in StO₂ at 1 minute of exercise (-73.2% vs 8.3%; P < .0001) and a greater decrease at minimum exercise StO₂ (-83.4% vs -16.1%; P < .0001). For patients with PAD, peak walking time, and 6-minute walking distance correlated with percent change in StO₂ at 1 minute of exercise (r = -0.76 and -0.67, respectively; P < .001) and time to minimum StO₂ (r = 0.79 and 0.70, respectively; P < .0001).

CONCLUSIONS

In this initial evaluation of a novel, low-cost NIRS device, lower extremities affected by PAD exhibited characteristic changes in calf muscle StO₂, which differentiated them from healthy controls and were strongly correlated with walking impairment. These findings confirm and expand on previous work demonstrating the potential clinical value of NIRS devices and the need for further research investigating the ability of low-cost NIRS technology to evaluate, diagnose, and monitor treatment response in PAD.

Influence of lung volume, fluid and capillary recruitment during positional changes and exercise on thoracic impedance in heart failure

It is unclear how dynamic changes in pulmonary-capillary blood volume (Vc), alveolar lung volume (derived from end-inspiratory lung volume, EILV) and interstitial fluid (ratio of alveolar capillary membrane conductance and pulmonary capillary blood volume, Dm/Vc) influence lung impedance (Z(T)). The purpose of this study was to investigate if positional change and exercise result in increased EILV, Vc and/or lung interstitial fluid, and if Z(T) tracks these variables.

METHODS

12 heart failure (HF) patients underwent measurements (Z(T), EILV, Vc/Dm) at rest in the upright and supine positions, during exercise and into recovery. Inspiratory capacity was obtained to provide consistent measures of EILV while assessing Z(T).

RESULTS

Z(T) increased with lung volume during slow vital capacity maneuvers (p<0.05). Positional change (upright→supine) resulted in an increased Z(T) (p<0.01), while Vc increased and EILV and Dm/Vc decreased (p<0.05). Moreover, during exercise Vc and EILV increased and Dm/Vc decreased (p<0.05), whereas, Z(T) did not change significantly (p>0.05).

CONCLUSION

Impedance appears sensitive to changes in lung volume and body position which appear to generally overwhelm small acute changes in lung fluid when assed dynamically at rest or during exercise.