Mechanical Allodynia Predicts Better Outcome of Surgical Decompression for Painful Diabetic Peripheral Neuropathy.

BACKGROUND: To determine the role of mechanical allodynia (MA) in predicting good surgical outcome for painful diabetic peripheral neuropathy (DPN). MATERIALS AND METHODS: Data of 192 patients with painful DPN were collected in this study, with 148 surgical patients and 44 patients in the control group. Both groups were further divided into subgroups based on the presence of MA on admission. Clinical evaluations including the visual analog scale (VAS), the Hospital Anxiety and Depression Scale (HADS), nerve conduction velocity (NCV), and high-resolution ultrasonography (cross-sectional area, CSA) were performed preoperatively and postoperatively. RESULTS: The levels of VAS and HADS and the results of NCV and CSA were improved in the surgical group (p < 0.05). In the surgical subgroups, pain reduction, psychiatric amelioration, improvement in NCVs, and the restoration of the CSA were observed in patients with signs of MA (p < 0.05), whereas only pain reduction, psychiatric amelioration, and restoration of the CSA were noted in patients without signs of MA (p > 0.05). Furthermore, better pain reduction was achieved in patients with MA when compared with those without MA (p < 0.05). CONCLUSIONS: MA is proved to be a reliable predictor of good surgical outcome for painful DPN.

Objective Evidence That Nerve Decompression Surgery Reduces Neuropathic DFU Recurrence Risk to Less than 5.

Significance: Despite 20 years of research and new treatment methods, diabetic foot ulcer (DFU) remains a common problem with frequent recurrences and complications. Recent Advances: There are reports that nerve decompression (ND) surgery has been observed to produce significantly fewer DFU recurrences than standard of care (SOC). The explanation of this apparent superiority has not been understood. Critical Issues: Microcirculation is understood to be involved in diabetic peripheral neuropathy (DPN) and DFU. There is an underappreciation of the participation in DPN of entrapment neuropathy (EN) due to nerve swelling and impingement in fibro-osseous tunnels. Reducing c-fiber compression in EN by ND generates recovery of subepidermal capillary flow. ND studies have found improved neuromuscular function and epidermal microcirculation phenomena, including chronic capillary ischemia (CCI) and pressure-induced vasodilatation (PIV). There is no current therapy recommended for impaired microcirculation. Clinical and animal evidence has demonstrated that release of locally compressed peripheral nerves improves the epidermal microcirculation which is under sympathetic control. Future Directions: Using epineurolysis to relieve nerve compressions is a physiology-based therapeutic intervention and provides the scientific foundation clarifying how ND reduces DFU recurrence risk. Incorporating ND with current SOC treatments could improve DFU recurrence risk, hard-to-heal ulcers, neuroischemic wounds, amputation risk, and the resulting costs to society. More studies using ND for DFU, especially evidence-based medicine Level I studies, are needed to confirm these preliminary outcomes.

Prevention of ulceration, amputation, and reduction of hospitalization: outcomes of a prospective multicenter trial of tibial neurolysis in patients with diabetic neuropathy.

This is the first multicenter prospective study of outcomes of tibial neurolysis in diabetics with neuropathy and chronic compression of the tibial nerve in the tarsal tunnels. A total of 38 surgeons enrolled 628 patients using the same technique for diagnosis of compression, neurolysis of four medial ankle tunnels, and objective outcomes: ulceration, amputation, and hospitalization for foot infection. Contralateral limb tibial neurolysis occurred in 211 patients for a total of 839 operated limbs. Kaplan-Meier proportional hazards were used for analysis. New ulcerations occurred in 2 (0.2%) of 782 patients with no previous ulceration history, recurrent ulcerations in 2 (3.8%) of 57 patients with a previous ulcer history, and amputations in 1 (0.2%) of 839 at risk limbs. Admission to the hospital for foot infections was 0.6%. In patients with diabetic neuropathy and chronic tibial nerve compression, neurolysis can result in prevention of ulceration and amputation, and decrease in hospitalization for foot infection.

A review of therapeutic nerve decompression for neuropathy in Hansen's disease with research suggestions.

Nerve decompression surgery for leprosy neuritis has a long history and large literature. New understanding of the high frequency of spontaneous recovery from nerve function impairment requires re-evaluation of the value of decompression in acute nerve dysfunction with strong evidence-based protocols. Several reports and theoretical considerations suggest research avenues that might offer hope for prevention of long-term complications and relief of impairment and disabilities.

Acute Improvement in Intraoperative EMG During Common Fibular Nerve Decompression in Patients with Symptomatic Diabetic Sensorimotor Peripheral Neuropathy: EMG and Clinical Attribute Interrelations.

STUDY AIMS: Electromyographic (EMG) recordings of the fibularis longus and tibialis anterior muscles were performed intraoperatively during nerve decompression (ND) of the common fibular nerve (CFN) in patients with symptomatic diabetic sensorimotor peripheral neuropathy. Patient demographics and clinical attributes were compared against changes in EMG after ND and analyzed for possible correlations. METHODS: Intraoperative changes in CFN EMG were analyzed for correlations against sex, age, body mass index (BMI), hemoglobin A1c (A1c), and type and duration of diabetes. RESULTS: Statistically significant changes were found between EMG changes and patient attributes, but no individual correlations were established. Significant EMG improvement was observed for both men and women (p < 0.0001 and p < 0.05, respectively), age groups (4th decade: p < 0.05; 5th decade: p < 0.05; 6th decade: p < 0.01; 7th decade: p < 0.005), diabetes duration (0-9 years: p = 0.002; 10-19 years: p = 0.002; 20-29 years: p = 0.03), and for type 1 and 2 diabetes (type 1: p < 0.005; type 2: p < 0.001). EMG improvement was greater in patients with the highest BMI levels (30-34.9: p = 0.014; 35-39.9: p = 0.013; > 39.9: p = 0.043), and highest A1c levels (> 6.4%; p < 0.0001). CONCLUSION: Although long-term clinical studies are needed, these results provide insight into which patients might benefit most from this surgery. These results also suggest that surgical ND can produce an acute improvement in nerve function for both men and women, for people with type 1 and 2 diabetes, and across a wide range of ages, BMI, A1c levels, and disease duration.

Early stage diabetic Charcot Foot syndrome may respond to nerve decompression.

Diabetic Charcot Foot syndrome has been postulated to require a triggering event to initiate its puzzling inflammatory process, characterized by bony resorption, pathologic fractures, soft tissue ligamentous failure, and destruction of foot architecture. Two cases are presented where multiple lower extremity nerve decompression was performed early in the Charcot process. Resolution of clinical signs and radiographic abnormalities rapidly followed. The observation that these events were temporally concurrent suggests that nerve entrapment might reasonably be investigated as one of the postulated triggering events for the Charcot Foot in diabetes. (c) 2009 Wiley-Liss, Inc. Microsurgery 2009.

Nerve decompression and neuropathy complications in diabetes: Are attitudes discordant with evidence?

External neurolysis of the nerve at fibro-osseous tunnels has been proprosed to treat or prevent signs, symptoms, and complications in the lower extremity of diabetes patients with sensorimotor polyneuropathy. Nerve decompression is justified in the presence of symptomatic compressed nerves in the several fibro-osseous tunnels of the extremities, which are known to be frequent in diabetes. Quite a body of literature has accumulated reporting results after such nerve decompression in the leg, describing pain relief and sensibility improvement, as well as balance recovery, diabetic foot ulcer prevention, curtailed ulcer recurrence risk, and amputation avoidance. Historical academic hesitance to endorse surgical treatments for pain and numbness in diabetes was based primarily on the early retrospective reports' potential for bias and placebo effects, and that the hypothetical basis for surgery lies outside the traditional etiology paradigm of length-dependent axonopathy. This reticence is here critiqued in view of recent studies using objective, measured outcome protocols which nullify such potential confounders. Pain relief is now confirmed with Level 1 studies, and Level 2 prospective information suggests protection from initial diabetic foot ulceration and most neuropathic ulcer recurrences. In view of the potential for nerve decompression to be useful in addressing some of the more difficult, expensive, and life altering complications of diabetic neuropathy, this secondary compression thesis and operative treatment methodology may deserve reassessment.

Acute Improvement in Intraoperative EMG Following Common Fibular Nerve Decompression in Patients with Symptomatic Diabetic Sensorimotor Peripheral Neuropathy: 1. EMG Results.

Background and Study Aims Electromyographic (EMG) recordings of the fibularis longus (FL) and tibialis anterior (TA) muscles were performed intraoperatively during common fibular nerve (CFN) nerve decompression (ND) in patients with symptomatic diabetic sensorimotor peripheral neuropathy (DSPN) and clinical nerve compression. Materials and Methods Forty-six legs in 40 patients underwent surgical ND by external neurolysis; FL and TA muscles were monitored intraoperatively. Evoked EMGs were recorded just prior to and within 1 minute after ND. Results Thirty-eight legs (82.6%) demonstrated EMG improvement 1 minute after ND. Sixty muscles (31 FL, 29 TA) were monitored, with 44 (73.3%) improving in EMG amplitude. Mean change in EMG amplitude represented a 73.6% improvement (p < 0.0001). Changes in EMG amplitudes correlated with visual analog scale pain improvement (p = 0.03). Conclusion This is the first report of acute changes in objective EMG responses during ND of CFN in DSPN patients and demonstrates that patients with symptomatic DSPN and clinical nerve entrapment have latent but functional axons that surgical ND can improve immediately.

Illustration of Cost Saving Implications of Lower Extremity Nerve Decompression to Prevent Recurrence of Diabetic Foot Ulceration.

The US diabetic foot ulcer (DFU) incidence is 3-4% of 22.3 million diagnosed diabetes cases plus 6.3 million undiagnosed, 858 000 cases total. Risk of recurrence after healing is 30% annually. Lower extremity multiple nerve decompression (ND) surgery reduces neuropathic DFU (nDFU) recurrence risk by >80%. Cost effectiveness of hypothetical ND implementation to minimize nDFU recurrence is compared to the current $6.171 billion annual nDFU expense. A literature review identified best estimates of annual incidence, recurrence risk, medical management expense, and noneconomic costs for DFU. Illustrative cost/benefit calculations were performed assuming widespread application of bilateral ND after wound healing to the nDFU problem, using Center for Medicare Services mean expense data of $1143/case for unilateral lower extremity ND. Calculations use conservative, evidence-based cost figures, which are contemporary (2012) or adjusted for inflation. Widespread adoption of ND after nDFU healing could reduce annual DFU occurrences by at least 21% in the third year and 24% by year 5, representing calculated cost savings of $1.296 billion (year 3) to $1.481 billion (year 5). This scenario proffers significant expense reduction and societal benefit, and represents a minimum 1.9× return on the investment cost for surgical treatment. Further large cost savings would require reductions in initial DFU incidence, which ND might achieve by selective application to advanced diabetic sensorimotor polyneuropathy (DSPN). By minimizing the contribution of recurrences to yearly nDFU incidence, ND has potential to reduce by nearly $1 billion the annual cost of DFU treatment in the United States.

Biologic Basis of Nerve Decompression Surgery for Focal Entrapments in Diabetic Peripheral Neuropathy.

The most recent (2011) National Diabetes Fact Sheet states the combined diagnosed and undiagnosed number of diabetes cases in the United States is approaching 25 million, and another 79 million are prediabetic. Of the diabetes patients, 60-70% suffer from mild to severe neuropathy. This combined loss of sensory and motor control in diabetic limbs is usually considered an irreversible, progressive process. Patients suffering from these losses are at a significantly higher risk for development of foot ulceration, frequently leading to infection and partial or major limb amputation. However, a review of focal nerve entrapment surgical decompression literature suggests that several diabetic sensorimotor polyneuropathy (DSPN) symptoms and complications are potentially partially reversible or preventable. Decompression surgery represents a paradigm shift in treatment protocols because it both relieves pain and restores protective sensation, while providing significant protection against a cascade of serious foot complications. This review surveys current research regarding the biological basis for diabetic focal entrapment neuropathy. Metabolic dysfunction related to aldose reductase, oxidative stress, and advanced glycation end products are considered and correlated to peripheral nerve enlargement and entrapment. In addition, observational studies correlated to that biological basis are presented as well as surgical outcomes illustrating the effect of decompression on DSPN symptomatic relief, nerve function, and protection against complications.

Nerve decompression after diabetic foot ulceration may protect against recurrence: a 3-year controlled, prospective analysis.

BACKGROUND: Nerve entrapment, common in diabetes, is considered an associated phenomenon without large consequence in the development of diabetes complications such as ulceration, infection, amputation, and early mortality. This prospective analysis, with controls, of the ulcer recurrence rate after operative nerve decompression (ND) offers an objective perspective on the possibility of frequent occult nerve entrapment in the diabetic foot complication cascade. METHODS: A multicenter cohort of 42 patients with diabetic sensorimotor polyneuropathy, failed pharmacologic pain control, palpable pulses, and at least one positive Tinel's nerve percussion sign was treated with unilateral multiple lower-leg external neurolyses for the indication of pain. All of the patients had healed at least one previous ipsilateral plantar diabetic foot ulceration (DFU). This group was retrospectively evaluated a minimum of 12 months after operative ND and again 3 years later. The recurrence risk of ipsilateral DFU in that period was prospectively analyzed and compared with new ulcer occurrence in the contralateral intact, nonoperated control legs. RESULTS: Operated legs developed two ulcer recurrences (4.8%), and nine contralateral control legs developed ulcers (21.4%), requiring three amputations. Ulcer risk is 1.6% per patient per year in ND legs and 7% in nonoperated control legs (P = .048). CONCLUSIONS: Adding operative ND at lower-leg fibro-osseous tunnels to standard postulcer treatment resulted in a significantly diminished rate of subsequent DFU in neuropathic high-risk feet. This is prospective, objective evidence that ND can provide valuable ongoing protection from DFU recurrence, even years after primary ulcer healing.

Reconsidering nerve decompression: an overlooked opportunity to limit diabetic foot ulcer recurrence and amputation.

Nerve decompression for relief of subjective diabetic sensorimotor polyneuropathy pain and numbness has been labeled of "unknown" benefit. Objective outcomes in treatment and prevention of diabetic foot complications are reviewed. There is growing evidence that plantar foot ulceration and recurrence in high-risk feet are minimized with this operation. Avoiding neuropathic and neuroischemic ulcer wounds should theoretically reduce amputations and perhaps mortality risk. Protective effects are hypothesized to act via relief of neuro-vascular entrapment, thereby improving neurally modulated tissue homeostasis factors. Nerve decompression deserves considerable research attention to understand its role in limiting foot complications. Its apparent benefits challenge the paradigm that diabetic neuropathy is a purely length-dependent axonopathy and may necessitate appreciation of superimposed nerve entrapment as an significant operant factor.

Low long-term risk of foot ulcer recurrence after nerve decompression in a diabetes neuropathy cohort.

BACKGROUND: Use of nerve decompression in diabetic sensorimotor polyneuropathy is a controversial treatment characterized as being of unknown scientific effectiveness owing to lack of level I scientific studies. METHODS: Herein, long-term follow-up data have been assembled on 65 diabetic patients with 75 legs having previous neuropathic foot ulcer and subsequent operative decompression of the common peroneal and tibial nerve branches in the anatomical fibro-osseous tunnels. RESULTS: The cohort's previously reported low recurrence risk of less than 5% annually at a mean of 2.49 years of follow-up has persisted for an additional 3 years, and cumulative risk is now 2.6% per patient-year. Nine of 75 operated legs (12%) have developed an ulcer in 4,218 months (351 patient-years) of follow-up. Of the 53 contralateral legs without decompression, 16 (30%) have ulcerated, of which three have undergone an amputation. Fifty-nine percent of patients are known to be alive with intact feet a mean of 60 months after decompression. CONCLUSIONS: The prospective, objective, statistically significant finding of a large, long-term diminution of diabetic foot ulcer recurrence risk after operative nerve decompression compares very favorably with the historical literature and the contralateral legs of this cohort, which had no decompression. This finding invites prospective randomized controlled studies for validation testing and reconsideration of the frequency and contribution of unrecognized nerve entrapments in diabetic sensorimotor polyneuropathy and diabetic foot complications.

Low recurrence rate of diabetic foot ulcer after nerve decompression.

BACKGROUND: This study reevaluates the previously reported subjective benefits of surgical nerve decompression in diabetes with an easily observable, fully objective outcome measure to eliminate the placebo effect and observer bias. METHODS: A retrospective review was conducted of a series of 75 feet in 65 patients with diabetes and previous neuropathic ulcer who had surgical decompressions of the peroneal and posterior tibial nerve branches at anatomical fibro-osseous tunnels. After a minimum of 12 months of follow-up, the incidence of ipsilateral ulcer was assessed. RESULTS: Postoperatively, four ulcer recurrences and four new-site ulcers developed in 187 patient-years. Mean follow-up was 2.49 years (range, 1-13 years). The combined linear annual risk of ipsilateral recurrence and new ulcer is 4.28%, the lowest reported in the scientific literature. CONCLUSIONS: Surgical decompression of lower-extremity nerves of high-risk feet at fibro-osseous anatomical tunnels was followed by a low annual incidence of ulcer recurrence. This objective outcome measure suggests benefits of nerve decompression in diabetic neuropathy, as have previous reports using pain and sensory change as subjective measures. Unrecognized nerve entrapment may frequently coexist with diabetic sensorimotor peripheral neuropathy in patients with diabetic foot ulcer.