An Interview with Dr. Dellon on Diabetic Neuropathy
Editor: Dr. Dellon, I have been doing the lower extremity nerve releases you described in the early 1990’s and been impressed by at least the subjective improvement my patients have almost universally reported. Are you still doing this procedure and how has you attitude toward the procedure changed since you first described it?
Dr. Dellon: Yes I still do this procedure. Since I first proposed the theory in 1988 that there was optimism for patients with diabetic neuropathy who also had nerve compressions in the lower extremity, my confidence in this theory has increased. The original basic science research done in rats in our lab has been confirmed in Maria Siemionow’s lab at the Cleveland Clinic and in labs in Turkey and Romania. After many individual retrospective case series reports, there has been a 38 center prospective multicenter study including 800 diabetics that showed a significant decrease in prevention of ulcers, amputations, and hospital admissions for foot infections, and a significant decease in pain, with the observational period being 3 years. The positive predictive value of the positive Tinel sign has been confirmed at 80%. The prevalence of diabetics with a positive Tinel sign and neuropathy has been observed to be 50 to 60% in the upper and lower extremity in a community based endocrinology practice. The first Level I study has demonstrated a significant decrease in pain. An economic cost benefit analysis using a decision-tree experimental design has been published demonstrating a significant savings if this “Dellon Approach” were implemented. Finally, I am proud to say that this surgery is being done in 21 countries outside the U.S.A.
Editor: Can you describe briefly for the readers the theory behind the surgical procedure?
Dr. Dellon: Part of the metabolic disease of diabetes is increased production of sorbitol from the excess serum glucose, by the enzyme aldose reductase. The increased sorbitol in the axoplasm causes water to be pulled into the nerve, causing increased nerve volume. If the peripheral nerve becomes swollen in an anatomic narrow space, like the carpal tunnel, fibular tunnel or tarsal tunnels, then there is relative ischemia, productive of paresthesias and, in time, chronic nerve compression. This is well accepted. It is the basis of the double crush hypothesis in diabetes, and the reason that diabetics with neuropathy have a high prevalence of nerve compressions. If we as surgeons can relieve carpal tunnel symptoms in the diabetic patient with neuropathy in the upper extremity, then, my hypothesis was, that we should be able to do this by decompressing anatomic sites of narrowing in the lower extremity. For those interested, I can supply the references for these studies; email me at ALDellon@Dellon.com.
Editor: Can you offer some thoughts on patient selection?
Dr. Dellon: Patient selection for nerve decompression in a person with diabetes and numbness, tingling, (with or without pain) for more than 6 months in the lower extremities;
- Patient must approach good sugar control, with HbA1c < 6.5 if possible
- Patient must have tried neuropathic pain medication and still have symptoms or be intolerant of the drugs
- Patient should weight under 300# or must reduce weight prior to surgery (preferable by diet or water walking, swimming)
- Patient must have no pedal edema
- Patient must have sufficient circulation in the feet for healing (palpable pulse, or Doppler measured ankle/brachial index > .7, or percutaneous PO2 > 40.
- Patient must meet normal criteria for elective surgery (cardiac and renal function)
- Patient must have a positive Tinel sign over the tibial nerve in the tarsal tunnel (positive predictive value of 80% for successful surgery)
Editor: Can you describe in general terms the actual surgery?
Dr. Dellon: The actual surgery is a neurolysis of the common peroneal nerve at the knee, the release of the four medial ankle tunnels, and the neurolysis of the deep peroneal nerve over the dorsum of the foot. In about 25% of the patients, there is also compression of the superficial peroneal nerve in the leg. In about 20% there is also compression of the tibial nerve at the soleal sling. Photos of these procedures are available at Dellon.com, in my book PAIN SOLUTIONS, written for patients, by clicking on the book cover, and then downloading chapter 2 for free. Also at Dellon.com, at the top of the page is Free Booklets. There you can download free the booklets on Foot Drop, on Tarsal Tunnels Syndrome, on Neuropathy, page 7 of each 8 page brochure has the published evidence base for the surgery. The surgery is done as an outpatient, and usually takes less than 2 hours of general anesthesia. The patient walks immediately after the surgery using a walker. Further surgical details are available in a review (Dellon, AL, The Dellon Approach to Neurolysis in the Neuropathy Patient with Chronic Nerve Compression, Handchir Mikrochir, Plast Chir, 40:1-10, 2008.) and will be present in a Supplement on “Pain” in Plastic and Reconstructive Surgery in the October 2014 issue.
Editor: Any special surgical tips?
Dr. Dellon: For the common peroneal nerve at the knee, there is a fibrous band almost always present beneath the peroneus muscles that must be released (Dellon AL, Ebmer J, Swier P: Anatomic variations related to decompression of the common peroneal nerve at the fibular head. Ann Plast Surg, 48: 30-34, 2002.). For the four medial ankle tunnels, it is critical to release the medial and lateral plantar tunnels into the bottom of the foot and to remove the septum between the tunnels in order to reduce the pressure upon the nerves (Barker, A.R., Rosson, G.D., Dellon, A.L., Pressure Changes in the Medial and Lateral Plantar, and Tarsal Tunnels Related to Ankle Position: A Cadaver Study, Foot & Ankle Internat., 28:250-254, 2007). For the superficial peroneal nerve, remember that one in four patients can have a high division of the nerve with a branch in the anterior compartment so both the lateral and anterior compartments must be released (Barrett SL, Dellon, AL, Rosson GD, Walters, L.: Superficial Peroneal Nerve: Clinical Implications of its Anatomic Variability, J Foot & Ankle Surgery, 45:174-176, 2006.).
Editor: I have had a couple of patients experience persistent wound drainage and healing problems especially with the posterior medial ankle incision. Any tips on how to avoid these pitfalls? By the way, both patients I’m thinking of asked me to do their contralateral limb once the wounds healed!
Dr. Dellon: When I teach the surgery for release of the four medial ankle tunnels, I demonstrate special attention to wound closure. Remember that walking immediately post-op with a walker is critical for nerve gliding and a good result. Wound healing starts with not cauterizing the skin edges. The bipolar coagulator is set on a low number, usually about 12. The skin edge is everted and the dermal bleeders are not cauterized in the dermis, but as they enter the dermis. Often poor healing is due to injury to the skin during this phase of hemostasis. Of course there must be excellent hemostasis. For wound closure, I use a row of interrupted intradermal 4-0 monocryl sutures first, and then both interrupted and continuous 5-0 nylon sutures are placed. Then I personally show the patient and accompanying person that they must “march” when using the walker, wearing the large, bulky, supportive dressing, a Robert Jones type of dressing with cotton. No black boots which inhibit ankle movement. When they walk, the must lift from the knee so reduce ankle motion to less than about 15 degrees of movement.
Editor: I get asked a lot about non-diabetic neuropathy…. What indications other than diabetic neuropathy are you offering the surgery? Chemotherapy induced neuropathy?
Dr. Dellon: The published results show the same success for idiopathic neuropathy as for diabetic neuropathy (Valdivia Valdivia, JM, Weinand, M, Maloney, CTJr, Blount, A, Dellon, AL, Surgical treatment of superimposed, lower extremity, peripheral nerve entrapment in patients with diabetic and idiopathic neuropathy, Ann Plastic Surg, 70:675-679, 2013.). We have reported similar results with neuropathy induced by the “platins” and “taxols” (Dellon AL, Swier P, Maloney CT, Levingood M, Werter, S., Chemotherapy-induced neuropathy: Treatment by decompression of peripheral nerve. Plast Reconstr Surg, 114:478-483, 2004.)
Editor: I think an important question is how does this surgical release affect the natural history of diabetic neuropathy? Do you have any thoughts on this?
Dr. Dellon: In the early basic science on rats made diabetic, even with blood sugars of 400 for one year (half of their lab lifetime), they walked like normal rats IF they had their tarsal tunnels released before they were made diabetic (Dellon ES, Dellon AL, Seiler WA IV: The effect of tarsal tunnel decompression in the streptozotocin-induced diabetic rat. Microsurg 15:265-268, 1994.). This study clearly shows a change in the natural history of diabetic neuropathy in a rat model. In a clinical retrospective review of 50 patients followed for a mean of 4.5 years (range 2 to 7 years), each patient had one leg that had a “Dellon Triple” procedure (neurolysis of three areas as described above). The other leg was observed for its natural history… obviously the blood sugar was the same in each leg! No ulcers or amputations occurred in the index limb of these patients. In contrast, there were 12 ulcers and 3 amputations in 15 different patients in contralateral limbs. This difference was significant at P < 0.001. It is concluded that decompression of lower extremity nerves in diabetic neuropathy changes the natural history of this disease, representing a paradigm shift in health care costs. (Aszmann OC, Tassler PL, Dellon AL: Changing the natural history of diabetic neuropathy: Incidence of ulcer/amputation in the contralateral limb of patients with a unilateral nerve decompression procedure, accepted Ann Plast Surg, 53:517-522, 2004. ).
Editor: One last question… many people have reported success with this procedure yet it does not seem as widely accepted as you would expect for a treatment that seems to so dramatically help patients that are really suffering. In fact, most of my referrals are still word of mouth… a satisfied patient refers their friends so to speak. How do you explain this reluctance to embrace this procedure and how do you think we “break through” to the “nonbelievers”?
Dr. Dellon: You are correct in your observations. Education about peripheral nerve problems and their surgical approach is poorly taught. We must begin to educate young doctors, even at the medical school level where they are still NOT taught about the presence of nerve compression in patients in general, except carpal tunnel syndrome, and certainly not about the prevalence of these in people with diabetes. My work has been published entirely in surgical journals. We must seek professionally to make internal medicine doctors, diabetologists, and endocrinologists aware of the evidence now available. Neurologist are a big part of the problem with patients NOT being referred, as they believe no one should have a nerve decompression unless there is a confirming electrodiagnostic study documenting nerve compression. However, they fail to admit in public that it is very difficult in a non-neuropathy patient to document the presence of tarsal tunnel syndrome, and it is extremely difficult, due to the already impaired nerve function, to demonstrate a tibial nerve compression in the presence of an axonal neuropathy. I often suggest to young surgeons that they speak to their nearest vascular surgeon, who sees a steady stream of patients with painful neuropathy who have normal vascular studies; these patients likely have a nerve compression and he can refer them to the peripheral nerve surgeon. Finally, whenever the patients come back to me with relief after surgery, I ask them to please let their family practice know and their diabetologists know that they are better.