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Tag Archive: Amputation prevention

  1. Diabetic Amputation Rates on the Rise

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    A new study by Geiss from Diabetes Care reveals a disturbing trend toward increasing rates of lower extremity amputations in young (18-44 y/o) and middle-aged (45-64 y/o) diabetic patients. This comes after a two-decade long decline in amputation rates in all diabetic patients. The study noted this upward spike in data collected from 2010-2015 in the US. As to the potential causes for this finding, the authors suggest a “fundamental failure” in amputation prevention. They go on to note:

    “Many amputations may be avoided through attention to self- and clinical care practices to manage risk factors, including glycemic control and cardiovascular disease risk factors, and through early detection and appropriate treatment of foot ulcers .
    Increasing rates of NLEAs (non-traumatic lower extremity amputations), particularly minor amputations, suggest either early prevention practices (e.g., self management education, appropriate footwear, foot exams, and identification of high-risk feet) might not be optimally performed to prevent foot ulcers and/or there may be delays in timely treatment of ulcers.”

    Indeed, this systemic failure to prevent these tragic events is a recurring frustration well known to those treating diabetic patients.  An aggressive team-based approach incorporating primary care, podiatry, diabetes educators, vascular surgeons, nutritionists and wound care specialists is required in addition to active and willing patient participation. Additionally, the importance of aggressive early prevention cannot be over emphasized. This is germane in the diabetic foot with regard to early detection of diabetic neuropathy. The graphic below illustrates the concept well. In essence, the earlier neuropathy is diagnosed, the earlier prevention can be implemented to avoid amputations. A worthy goal for patients and providers alike.

    Earlier diagnosis of neuropathy indicated by the yellow arrow could help avoid amputations through earlier preventative intervention.

    In contrast, current guidelines focus on identifying Loss of Protective Sensation (LOPS) as a trigger for prevention.

     

  3. A Week’s Worth of Reasons to Reconsider Monofilament Testing for DPN: Sunday

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    monofilament-sundaySunday: Monofilament testing under ideal conditions assesses light touch by applying pressure to the skin of the foot. Light touch is mediated mostly by large fiber encapsulated nerve receptors and some small nerve fiber mechanoreceptors (see Figure one). For decades, providers have been advised by researchers and expert consensus to accept this as a valid “proxy” test for loss of protective sensation (LOPS)(1). LOPS, more accurately interpreted as a loss of pain sensation, is a small nerve fiber function mediated by specialized free nerve endings known as nociceptors. The obvious question is whether or not a test assessing mostly large fiber nerve function can imply a loss of small fiber nerve function? Although there is thought to be some correlation between the two it is difficult to make a direct comparison. For example, nerve conduction velocity (NCV) testing, acknowledged as the “Gold Standard” for diagnosing neuropathy, tells us nothing about small fiber nerve function.  This lack of direct correlation is heightened in light of recent research demonstrating that small fiber neuropathy (SFN) precedes large fiber neuropathy in the feet of diabetic patients (2).

    Given these facts, the argument can be made that there is an intrinsic flaw in the test itself. Although not commonly discussed in the literature, providers have no doubt seen its impact over the years in the false negatives elicited by the test. The most glaring examples are those patients who will “pass” the monofilament exam while failing to react to a sharp stimulus or complain of pain when presenting with a full-thickness foot ulcer. In these cases, patients most likely are passing the exam with their intact large fiber nerve receptors. Although these may be exceptions, periodic false negatives combined with the errors induced by confounding variables noted in days Monday-Saturday lead one to reconsider the validity of the test as medicine moves into the 21st century. Ultimately providers should consider whether LOPS as diagnosed by the monofilament is effective at further reducing diabetic foot complications.

    nerve-function-graphic2

    Fig. 1. Large and small nerve fiber functions in the skin of the foot. Note that pain perception resides on the small fiber side and light touch is the only shared function.

    1.Boulton, AJ, Armstrong, DG, et al. Comprehensive Foot Examination and Risk Assessment. Diabetes Care 31(8):1679-1685, 2008.

    2. Breiner A, Lovblom LE, Perkins BA, Bril V. Does the prevailing hypothesis that small-fiber dysfunction precedes large-fiber dysfunction apply to type 1diabetic patients? Diabetes Care. 2014 May;37(5):1418-24.

     

  4. A Week’s Worth of Reasons to Reconsider Monofilament Testing for DPN: Saturday

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    monofilament3Saturday: The test provides ambiguous results and poor inter-rater reliability even when done correctly (1). Providers have recently called into question exactly how useful the device is at identifying diabetic patients with LOPS (2).

    1. Collins S, Visscher P, De Vet HC, Zuurmond WW, Perez RS. Reliability of the Semmes Weinstein Monofilaments to measure coetaneous sensibility in the feet of healthy subjects. Disabil Rehabil. 2010;32(24):2019-27.

    2. Dros J, et al: Accuracy of monofilament testing to diagnose peripheral neuropathy:a systematic review. Ann Fam Med 7: 555, 2009.