Comment on IWGDF ulcer prevention guidelines

The IWGDF 2019 Updated Guidelines for prevention of foot ulcers in diabetes advise that nerve decompression surgery not be considered. This nerve decompression option has similar scientific supporting evidence to other surgeries which are recommended. The sanction ignores a large body of non‐Level 1 evidence demonstrating various beneficial outcomes of ND including pain relief, DFU prevention, and protection from recurrence and amputation.


E D I T O R I A L Comment on IWGDF ulcer prevention guidelines
We now know that in DPN, local nerve compression and its sequelae need not be permanent nor irremediable. Although ND evidence is mostly Level 2 or 3, clinical, uncontrolled and often retrospective, it is hardly meagre and compares favourably with contrary Level 5 expert opinion. Surgical site infection has been shown to be linked not to a diabetes diagnosis but to the neuropathy. 7 Nickerson reviewed reports of the use of ND in DPN producing outcome improvements in pain relief, touch and vibratory sensibility, thermal sensation, perineural pressure, electrophysiologic EMG and NCV measures, pedal transcutaneous pO 2 , arterial flow pulsatility, balance, protection from initial DFU, lowest described ulcer recurrence risk and hospitalization for foot infections and amputation. 8 Since that review, further evidence has been published/addressing delayed mortality, prolonged survival without recurring ulceration, and improved intra-operative evoked motor potentials. 6,9 Animal models of induced diabetes with evolving sciatic nerve trunk enlargement and compression demonstrate progressive behavioural, myelination and electrophysiologic changes, This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. but recovery to nearly normal status by 3 months following ND. 10 This animal modelling closely mimics the course and pathologic findings of human DPN.
Aside from improvements in these many outcome measures, another rarely mentioned phenomenon may be an important DFU correlate which is also responsive to ND. This is the circulation phenomenon called pressure-induced vasodilatation (PIV).
Zwanenburg et al have reviewed the concept and the evidence that local circulation, as measured by cutaneous laser Doppler flowmetry, is normally increased by gradual application of moderate pressure as might exist on pedal skin while standing and walking. 11 This local vasodilatation effect is on the order of 40% improvement in superficial blood flow. PIV blockade or absence has been demonstrated both in nerve-injury animal models and clinically in both human spinal cord injury and diabetic neuropathy.
It is known that use of innervated pedicled or free flaps to manage human pressure ulcerations has a better survival record, suggesting PIV restoration is useful. In a rat model, PIV is impaired following chronic nerve compression and restored following release.

Such recovery of PIV response begs for confirmation in human DPN after ND.
Acute pain is also known to block PIV in animals. The relevance to chronic human DPN pain is unknown. We do know that chronic DPN pain has been responsive to ND in most cases, 12  risks. 13 The results show durable VAS pain score reductions from >8/10 to <3/10 which last over 4 years. We anxiously await that study's peer review and publication.
In DFU recurrence, overall expectations from 19 studies are that annual recurrence risk approximates 40%. 14  Still, it is an attractive hypothesis, supported by much published literature, to propose that ND effects on pain relief, restoration of protective sensation, and recovery of PIV in combination can explain these patients' observed resistance to initial or recurrent DFU. We may well find that attacking the secondary compression neuropathy will be more successful and cost effective than current measures emphasizing surveillance and pressure management of DPN patients at high risk. But this remains speculation until academia is willing to participate in designing and joining ND research projects. Should ND prove an effective protection from DFU recurrence as proponents have reported, possibilities exist that the minimized DPN, restored protective sensation, and PIV recovery can be engaged to also prevent initial ulcerations, minimize amputations and avoid early mortality. 9 The millions facing diabetes neuropathy complications would love to hear such prospects for optimism.