Monday, July 18, 2022
Disclaimer: I am not a physician. I researched this topic for reasons of my own health.
SUMMARY: Surgery for diabetic peripheral neuropathy of the feet and lower legs – with the strongest evidence being for pain relief – is considered when there is diagnostic evidence that the nerves are enlarged in cross-section and compressed by thickened surrounding tendons, ligaments and other support structures, and when non-surgical treatments are not providing adequate relief. In contrast, the evidence for surgery as treatment for idiopathic peripheral neuropathy (IPN) of the feet and lower legs is weak, as pain is not the dominant symptom of IPN, and the evidence comes from three uncontrolled clinical trials: Valdivia 2013, Siemionow 2006, Valdivia 2005. It is possible that Valdivia 2013 represents adding more subjects to those already reported on in Valdivia 2005.
PERIPHERAL NEUROPATHY: refers to symptoms of nerve cell damage to nerves in the legs and arms. Nuclei of these cells are in the spinal column. Axons of these cells extend to legs and arms. Axon length matters, so feet and legs are often affected before hands and arms. Sensory nerves are typically affected before motor nerves, so symptoms of pain, numbness, burning sensation, tingling, etc., appear before poor motor control. People may complain that it feels as if there are pebbles inside their shoes, or contrariwise, that they have little-to-no sensation from their feet, contributing to loss of balance. Foot injuries such as blisters, cuts and bruises may go unnoticed.
Diabetes is a major cause of peripheral neuropathy. Nerves are enlarged. Ultrasound can be used to confirm that the cross-sectional diameter of nerves is increased by 25-50%. If the nerve is traveling through a restricted area, this increase in size can result in construction of the nerve and increased symptoms of numbness. Some researchers believe that roughly 30-60% of patients with diabetes suffering from neuropathy have a component of peripheral nerve compression.
Other causes include autoimmune diseases, viral and bacterial infections, inherited disorders, tumors pressing on nerves, vitamin B12 deficiency, kidney disease, lover disease, and others. If no known cause is identified, the condition is referred to as idiopathic peripheral neuropathy.
HISTORY OF DECOMPRESSION SURGERY: Starting in the early 1990s. surgery has been proposed as a treatment for peripheral neuropathy. The theory is that the nerves are compressed. For legs and feet, the surgery sites are peroneal nerve at knee, tibial nerve at ankle and peroneal nerve at dorsum of the foot. A review (Nickerson 2017) took the position that medical ‘ownership’ of treating symptoms of nerve disorders became prejudice against surgeons ‘trespassing’ where they did not belong. Nickerson referred to the opposition as “common and committed.” Reviews published circa 2006-08 that a surgical approach was “unproven.” Nickerson concluded that based on more trial results and reviews, was that the surgical approach “may deserve reassessment.”
Per Nickerson, the strongest positive evidence is for diabetic sensorimotor polyneuropathy (DSPN), and within that patient subset, for pain relief. To a more modest degree, there are clinical improvements in sensation, balance, control of sway with eyes closed, etc. The evidence for surgery for DSPN also includes lowering risk of leg/foot ulcers, amputations and improved life expectancy (Rinkel 2021).
There is much less surgery evidence for non-diabetic neuropathy, i.e., idiopathic peripheral neuropathy. IPN is much less likely to have pain as the major symptom, whereas pain relief is the strongest result for diabetic surgery. If surgery is to be considered for IPN, there should first be a confirmation nerve compression, followed by a progressive surgical strategy, for example, one leg, ankle only, rather than both legs, knee, ankle and foot.
EVIDENCE FOR SURGERY: See references. Not included are several older clinical trial reports that enrolled only diabetic patients. Rinkel 2021, Rinkel 2018, Nickerson 2017 and Tu 2017 are reviews of long-term follow-up of diabetes patients. Maurik 2015 and Maurik 2014 are diabetes clinical trial reports. Valdivia 2013, Siemionow 2006 and Valdivia 2005 included both diabetic and IPN subjects. Valdivia 2013 reported on 96 subjects with diabetic neuropathy and 62 with idiopathic neuropathy, and reported “There was no difference in outcomes between patients with diabetic versus idiopathic neuropathy in response to nerve decompression.” Valdivia 2013 may have incorporated subjects from Valdivia 2005.
The clinical trials were not placebo controlled via sham surgery. Instead, there is analysis comparing before to after, or operated leg to not operated leg. There is a known strong placebo effect for pain relief across many conditions, for example, osteoarthritis or migraine, so pain relief results may in part be a placebo effect.
DIAGNOSIS: Pain is measured with a subjective Visual Analog Scale (VAS) ranking zero to ten. Touch sensation is measured in several ways, including increasing pressure until touch is perceived, and with the ability to distinguish between one-point and two-point touching. “Tinel Sign” is considered positive if finger tapping on a nerve elicits tingling. Temperature perception (cold or hot) can be impaired. All of these can be improved after surgery, but pain is the most sensitive marker.
A skin biopsy can determine whether nerve cell endings are present. Nerve conduction velocity and electromyography are tests. Ultrasound checks for nerve enlargement, and can be before and after surgery for change. Mysteriously, surgery on one leg has been shown to reduce nerve cross-sectional area and pain in the non-operated leg, perhaps suggesting a reduction in circulating inflammatory compounds.
NON-SURGICAL TREATMENTS: There is a long list, with varying degrees of efficacy: Aspirin and other NSAIDS, topical products such as capsaicin, Transcutaneous electronic nerve stimulation, anti-depressant drugs can relieve chronic pain, corticosteroids, opiods, dietary supplements, etc.
Abstracts for these refs can be seen by searching on "PubMed" and within PubMed, on PMID #
Rinkel WD, Franks B, Birnie E, et al. Cost-Effectiveness of Lower Extremity Nerve Decompression Surgery in the Prevention of Ulcers and Amputations: A Markov Analysis. Plast Reconstr Surg. 2021 Nov 1;148(5):1135-45. PMID: 34705790.
Rinkel WD, de Kleijn JL, Macaré van Maurik JFM, Coert JH. Optimization of Surgical Outcome in Lower Extremity Nerve Decompression Surgery. Plast Reconstr Surg. 2018 Feb;141(2):482-96. PMID: 29068902.
Nickerson DS. Nerve decompression and neuropathy complications in diabetes: Are attitudes discordant with evidence? Diabet Foot Ankle. 2017 Sep 6;8(1):1367209 PMID: 28959382.
Tu Y, Lineaweaver WC, Chen Z, Hu J, Mullins F, Zhang F. Surgical Decompression in the Treatment of Diabetic Peripheral Neuropathy: A Systematic Review and Meta-analysis. J Reconstr Microsurg. 2017 Mar;33(3):151-57. PMID: 27894152.
Macaré van Maurik JF, ter Horst B, van Hal M, Kon M, Peters EJ. Effect of surgical decompression of nerves in the lower extremity in patients with painful diabetic polyneuropathy on stability: a randomized controlled trial. Clin Rehabil. 2015 Oct;29(10):994-1001. PMID: 25381348.
van Maurik JFMM, van Hal M, van Eijk RPA, Kon M, Peters EJG. Value of surgical decompression of compressed nerves in the lower extremity in patients with painful diabetic neuropathy: a randomized controlled trial. Plast Reconstr Surg. 2014 Aug;134(2):325-32. PMID: 24732651.
Valdivia Valdivia JM, Weinand M, Maloney CT Jr, Blount AL, Dellon AL. Surgical treatment of superimposed, lower extremity, peripheral nerve entrapments with diabetic and idiopathic neuropathy. Ann Plast Surg. 2013 Jun;70(6):675-79. PMID: 23673565.
Dellon AL. The Dellon approach to neurolysis in the neuropathy patient with chronic nerve compression. Handchir Mikrochir Plast Chir. 2008 Dec;40(6):351-60. PMID: 19051159.
Dellon AL. The four medial ankle tunnels: a critical review of perceptions of tarsal tunnel syndrome and neuropathy. Neurosurg Clin N Am. 2008 Oct;19(4):629-48, vii. PMID: 19010287.
Ducic I, Taylor NS, Dellon AL. Relationship between peripheral nerve decompression and gain of pedal sensibility and balance in patients with peripheral neuropathy. Ann Plast Surg. 2006 Feb;56(2):145-50. PMID: 16432321.
Siemionow M, Alghoul M, Molski M, Agaoglu G. Clinical outcome of peripheral nerve decompression in diabetic and nondiabetic peripheral neuropathy. Ann Plast Surg. 2006 Oct;57(4):385-90. PMID: 16998329.
Valdivia JM, Dellon AL, Weinand ME, Maloney CT Jr. Surgical treatment of peripheral neuropathy: outcomes from 100 consecutive decompressions. J Am Podiatr Med Assoc. 2005 Sep-Oct;95(5):451-54. PMID: 16166462.
Posted by David Mark at 6:56 AM