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SPECIAL ARTICLES: Vinay Chaudhry, James C. Stevens, John Kincaid, and Yuen T. So Practice Advisory: Utility of surgical decompression for treatment of diabetic neuropathy: Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology Neurology 2006; 66: 1805-1808 [Abstract] [Full text] [PDF]

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Practice Advisory: Utility of surgical decompression for treatment of diabetic neuropathy

Peter J. Dyck   (22 September 2006)

Practice Advisory: Utility of surgical decompression for treatment of diabetic neuropathy

A. Lee Dellon, MD   (22 September 2006)

Reply from the Authors

Vinay Chaudhry, MD, James C. Stevens, MD, John Kincaid, MD and Yuen T. So, MD, PhD   (22 September 2006)

Practice Advisory: Utility of surgical decompression for treatment of diabetic neuropathy 22 September 2006
Peter J. Dyck, Mayo Clinic 200 First Street SW, Rochester, MN 55905 Send Correspondence to journal: Re: Practice Advisory: Utility of surgical decompression for treatment of diabetic neuropathy dyck.peter{at}mayo.edu Peter J. Dyck	The recently published Practice Advisory was needed, is timely and sensible. [1] The Therapeutics and Technology Assessment Subcommittee of the AAN found little compelling evidence favoring decompression of leg nerves in diabetic symmetric distal sensorimotor polyneuropathy (DSPN). It should be emphasized that it is decompression of leg nerves at anatomical sites not known to be entrapped that is being discussed (which may not have been sufficiently emphasized in the Advisory) and to provide corrected prevalence figures for diabetic sensorimotor polyneuropathy (DSPN) ¨C the figures provided in the Advisory were for all types of neuropathy (i.e. 66% for type 1 and 59% for type 2 diabetics). [1] For DSPN, the estimated prevalence is 54 percent for type 1 and 45 percent for type 2 diabetes. The minimal criteria used for the diagnosis of DSPN were: two or more abnormalities from among neuropathy symptoms, signs, attributes of nerve conduction, quantitative sensation tests or heart beat decrease with deep breathing or Valsalva maneuver (in all cases using standard tests with values corrected for age, gender and physical variables). When the minimal criterion for DSPN is a composite score of 5 attributes of nerve conduction of the leg (with values expressed as normal deviates [from percentiles] and with all abnormalities expressed in the upper tail of the normal distribution [summated normal deviates of 5 attributes of nerve conduction], the estimated percentages are 55 and 32 percent respectively. Providing these corrected prevalence values is not meant to detract from the main conclusion of the Advisory. Reference 1. Chaudhry V, Stevens JC, Kincaid J, So YT. Practice Advisory: Utility of surgical decompression for treatment of diabetic neuropathy: Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology 2006;66:1805-1808. Disclosure: The author reports no conflicts of interest.
Practice Advisory: Utility of surgical decompression for treatment of diabetic neuropathy 22 September 2006
A. Lee Dellon, MD, Johns Hopkins University Suite 370, 3333 N. Calvert St., Baltimore, MD 21218 Send Correspondence to journal: Re: Practice Advisory: Utility of surgical decompression for treatment of diabetic neuropathy aldellon{at}delloninstitutes.com A. Lee Dellon, MD	I thank the Therapeutics and Technology Assessment Subcommittee (TTA) for awakening the medical community to the hypothesis that, if pathophysiology in diabetic polyneuropathy (DPN) renders peripheral nerves susceptible to chronic compression, then neurolysis at sites of superimposed compression can relieve pain, restore sensibility, and prevent ulceration/amputation. [1] Subsequent systematic reviews may differ with the conclusion that this treatment is "unproven", and consider six of these eleven papers as prospective, two as blinded, one as case-controlled, and all homogenous in their inclusion criteria: patients with DPN with a superimposed nerve compression who are in good glycemic control and unresponsive to neuropathic medications. High quality criteria were also used for outcome measures, which, short-term, are VAS for pain and quantitative measures for sensibility, similar to those in the evidence-based drug studies TTA quoted. Long-term outcome objective measures are presence/absence of ulcer/amputation. A systematic review of the surgical literature raises additional questions: 1. If it is not disingenuous to require electrodiagnostic studies to document nerve compression and success of surgical decompression in diabetics, then TTA must delineate criteria for: a) that diagnosis; and b) what constitutes post-operative improvement electrophysiologically. This may be difficult. For a), in the presence of axonopathy with its own demyelination, demonstration of segmental tibial nerve slowing in the tarsal tunnel may not be possible (especially since this diagnosis is not possible in the upper extremity). [2] For b), since median nerve remyelination doesn't occur normally after carpal tunnel decompression, can criteria for post-operative improvement in diabetic tibial nerve be defined reliably? 2. Surgeons use Tinel's sign as electrophysiologists use Kimura's inching to identify the site of nerve compression. Given 1a) above, the TTA committee should document the validity and reliability of Tinel's sign to identify nerve compression in DPN, because positive Tinel sign has 90% positive predictive value for success of nerve decompression in this population. [3] Therefore, should the Tinel sign be part of the routine neurological exam in DPN? [4] Currently, it is not. If the AAN does not look for nerve compression in DPN, clearly they will not find it. What would AAN consider randomizing as control group(s) for progressive, irreversible DPN? Will an IRB ethically accept sham surgical controls? One day, a neurologist will enter surgery, witness the peripheral nerve compression, examine the patient post-operatively, and observe patient laughter when the foot is tickled. Will this be Level I or Level V evidence? References 1. Chaudhry V, Stevens JC, Kincaid J, So YT. Practice Advisory: Utility of surgical decompression for treatment of diabetic neuropathy; Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology, Neurology, 2006;66:1805-1808. 2. Perkins BA, Olaleye D, Bril V. arpal tunnel syndrome in patients with diabetic polyneuropathy, Diabetes Care 2002;25:565-569. 3. Lee CH, Dellon AL. Prognostic ability of Tinel sign in determining outcome for decompression surgery in diabetic and non-diabetic neuropathy, Ann Plast Surg 2004; 53:523-27. 4. Miller TM, Johnston CS. Should the Babinski sign be part of the routine neurologic examination? Neurology, 2005;65:1165-1168. Disclosure: A. Lee Dellon, MD has a proprietary interest in the Pressure-Specified Sensory Device and is Director of the Dellon Institutes for Peripheral Nerve Surgery.
Reply from the Authors 22 September 2006
Vinay Chaudhry, MD, Johns Hopkins Outpatient Center JHOC 5072 A, 601 North Caroline Street, Baltimore, MD 21287, James C. Stevens, MD, John Kincaid, MD and Yuen T. So, MD, PhD Send Correspondence to journal: Re: Reply from the Authors vchaudh{at}jhmi.edu Vinay Chaudhry, MD, et al.	We thank Dr. Dyck for emphasizing that the report dealt with decompression of lower extremity nerves. The data on prevalence are appreciated as well. We also appreciate Dr. Dellon’s letter, and offer the following in response to his comments. First, the literature classification criteria used by AAN and TTA are vigorous, validated, and transparent. The classification methodology determined that all the studies on surgical decompression of diabetic polyneuropathy cited are Class IV. The shortcomings of each of the studies are outlined in the Practice Advisory [1] and the companion evidence table published on the Neurology web site (www.neurology.org). We did not find unbiased evidence to recommend the use of surgical decompression for diabetic distal symmetrical polyneuropathy. Second, as stated in the review, the pivotal question is whether lower extremity decompressive surgery is beneficial for the treatment of diabetic distal symmetrical polyneuropathy; we did not address the well-accepted compressive neuropathies such as carpal tunnel or tarsal tunnel entrapments. The TTA committtee did not feel that it is appropriate to combine the symmetrical length-dependent distal polyneuropathy and focal compressive neuropathies. Third, it is not the intent of the review to assess the diagnostic value of Tinel’s sign or the various methods for diagnosis of tarsal tunnel syndrome. However, just like carpal tunnel syndrome, Tinel’s sign is only one of many clinical features that are helpful in making a diagnosis of entrapment neuropathy. Valid diagnosis of entrapment and non-compressive neuropathies can only come from careful clinical assessment supplemented when necessary by electrophysiological and other laboratory testing. Finally, a properly designed study can and should be undertaken as outlined in Recommendations for Future Research in our review. [1] Credible information may be obtained with appropriate attention to patient selection, treatment randomization, blinding and choice of outcome measures. Disclosure: The authors report no conflicts of interest.