Tibial nerve decompression for the prevention of the diabetic foot: a cost-utility analysis using Markov model simulations

The Impact of Underlying Conditions on Quality-of-Life Measurement Among Patients with Chronic Wounds, as Measured by Utility Values: A Review with an Additional Study

Significance: Quality of life (QoL) is important to patients with chronic wounds and is rarely formally evaluated. Understanding what comorbidities most affect the individual versus their wounds could be a key metric. Recent Advances: The last 20 years have seen substantial advances in QoL instruments and conversion of patient data to a single value known as the health utilities index (HUI). We review these advances, along with wound-related QoL, and analyze real-world comorbidities challenging wound care. Critical Issues: To understand the impact of underlying comorbidities in a real-world patient population, we examined a convenience sample of 382 patients seen at a hospital-based outpatient wound center. This quality reporting study falls outside the regulations that govern human subject research. Comorbid conditions were used to calculate HUIs using a variety of literature-reported approaches, while Wound-Quality-of-Life (W-QoL) questionnaire data were collected from patients during their first visit. The mean number of conditions per patient was 8; 229 patients (59.9%) had utility values for comorbidities/conditions, which were worse/lower than their wounds' values. Sixty-three (16.5%) patients had depression and/or anxiety, 64 (16.8%) had morbid obesity, and 204 (53.4%) had gait and mobility disorders, all of which could have affected W-QoL scoring. The mean minimum utility value (0.5) was within 0.05 units of an average of 13 studies reporting health utilities from wound care populations using the EuroQol 5 Dimension instrument. Future Directions: The comorbidity associated with the lowest utility value is what might most influence the QoL of patients with chronic wounds. This finding needs further investigation.

Is Surgical Repair With Nerve Allograft More Cost-Effective Than Non-Surgical Management for Persistent Trigeminal Neuropathy? Initial Assessment With Markov Model

PURPOSE

Persistent trigeminal neuropathy (PTN) is associated with high rates of depression, loss of work, and decreased quality of life (QoL). Nerve allograft repair can achieve functional sensory recovery in a predictable manner; however, it bears significant upfront costs. In patients suffering from PTN, is surgical repair with allogeneic nerve graft, when compared to non-surgical therapy, a more cost-effective treatment option?

MATERIALS AND METHODS

A Markov model was constructed with TreeAge Pro Healthcare 2022 (TreeAge Software, Massachusetts) to estimate the direct and indirect costs for PTN. The model ran for 40 years with 1-year-cycles on a 40-year-old model patient with persistent inferior alveolar or lingual nerve injury (S0 to S2+) at 3 months without signs of improvement, and without dysesthesia or neuropathic pain (NPP). The 2 treatment arms were surgery with nerve allograft versus non-surgical management. There were 3 disease states, functional sensory recovery (S3 to S4), hypoesthesia/anesthesia (S0 to S2+), and NPP. Direct surgical costs were calculated using the 2022 Medicare Physician Fee Schedule and verified with standard institutional billing practices. Non-surgical treatment direct costs (follow-up, specialist referral, medications, imaging) and indirect costs (QoL, loss of employment) were determined from historical data and the literature. Direct surgical costs for allograft repair were $13,291. State-specific direct costs for hypoesthesia/anesthesia were $2,127.84 per year, and $3,168.24 for NPP per year. State-specific indirect costs included decreased labor force participation, absenteeism, and decreased QoL.

RESULTS

Surgical treatment with nerve allograft was more effective and had a lower long-term cost. The incremental cost-effectiveness ratio was -10,751.94, indicating surgical treatment should be utilized based on efficiency and cost. With a willingness-to-pay threshold of $50,000, the net monetary benefits of surgical treatment are $1,158,339 compared to $830,654 for non-surgical treatment. With a standard threshold incremental cost-effectiveness ratio of 50,000, the sensitivity analysis shows that surgical treatment would remain the preferred choice based on efficiency even if surgical costs were doubled.

CONCLUSION

Despite high initial costs of surgical treatment with nerve allograft for PTN, surgical intervention with nerve allograft is a more cost-effective treatment option when compared to non-surgical therapy.

Paradoxical Changes of Cutaneous Microcirculation and Sympathetic Fibers of Rat Hind Limbs after Sciatic Nerve Compression

BACKGROUND

Recent studies show evidence that surgical nerve decompression could improve cutaneous blood flow (CBF), which might benefit ulcer healing. However, the change of CBF and sympathetic fibers after nerve compression is poorly understood. In the current study, a unilateral sciatic nerve compression model was created in Sprague-Dawley rats.

METHODS

A laser Doppler imaging system was applied to assess the CBF of the regions below the ankles. Immunohistochemistry and transmission electron microscopy were used to investigate the histopathologic changes of sympathetic fibers in sciatic nerve samples.

RESULTS

Laser Doppler imaging revealed decreased CBF of both the lesional limb and the contralesional limb, which occurred earlier in the lesional side, indicating an enhanced sympathetic tone on vasomotor function. Intraneural density of sympathetic fibers decreased on both sides and the ultrastructure of unmyelinated fibers of both sides degenerated in a nonsynchronized manner.

CONCLUSIONS

The study revealed nonsynchronized reduced CBF of bilateral hind limbs with paradoxically degenerated and diminished sympathetic fibers in bilateral sciatic nerves after unilateral sciatic nerve compression. These results may validate the importance of and broaden the indications for surgical nerve decompression in preventing or treating foot ulcers.

Does Lower Extremity Nerve Decompression Surgery Improve Quality of Life?

BACKGROUND

Entrapment neuropathies are more prevalent in patients with diabetes than in healthy patients. The aim of this study was to assess the effects of lower extremity nerve decompression surgery on quality of life and clarify predictors of this surgical outcome and the incidence of surgical site problems.

METHODS

Patients who underwent lower extremity nerve decompression surgery between September of 2017 and March of 2019 were followed prospectively at the outpatient clinic of University Medical Center Utrecht. The common, superficial, and deep peroneal nerve and tibial nerve at the tarsal tunnel and soleal sling were decompressed if an entrapment was diagnosed. The primary study outcome was quality of life as measured by the Norfolk Quality of Life-Diabetic Neuropathy questionnaire. Secondary outcomes of interest were change in Michigan Neuropathy Screening Instrument score, predictors of the Norfolk score at follow-up, and the occurrence of complications.

RESULTS

Sixty patients underwent surgery (45 unilateral, 15 bilateral), with a median postoperative follow-up of 13.0 months (interquartile range, 7.3 to 18.0 months). Quality of life improved significantly in this period of observation [baseline median, 46.0 (34.0 to 62.0) versus follow-up median, 37.0 (20.0 to 60.0); p = 0.011], as did Michigan Neuropathy Screening Instrument scores [7.0 (5.0 to 9.0) versus 3.0 (0.0 to 6.5); p < 0.01]. Predictors of quality of life were a higher baseline quality of life score [β, 0.59 ( p = 0.001)], longer follow-up time [β, 2.34 ( p < 0.001)], and hypertension [β, 16.38 ( p = 0.03)]. A total of 26.7 percent of patients had surgical site problems, including wound infections (18.3 percent).

CONCLUSIONS

Lower extremity nerve decompression surgery significantly improves quality of life by reducing neuropathy symptoms in patients with lower extremity nerve compressions. Attention should be given to lowering the risk of wound complications.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Lower Extremity Nerve Decompression for Diabetic Peripheral Neuropathy: A Systematic Review and Meta-analysis

Background:

Diabetic peripheral neuropathy (DPN) is a leading cause of morbidity. This systematic review and meta-analysis evaluate the efficacy of lower extremity nerve decompression in reducing DPN symptoms and complications.

Methods:

A database search was performed using Medline, Embase, Google Scholar, and Cochrane Central Register of Controlled Trials. Articles addressing surgical decompression of lower limb peripheral nerves in patients with diabetes were screened for inclusion. Two independent reviewers undertook the assessment. Methodological quality measures were the Cochrane risk of bias and Newcastle-Ottawa scale.

Results:

The pooled sample size from 21 studies was 2169 patients. Meta-analysis of 16 observational studies showed significant improvement in the visual analog scale (VAS) (P < 0.00001) and two-point discrimination (P = 0.003), with strong reliability. Decompression of the tarsal tunnel region had the highest improvement in VAS [MD, 6.50 (95% CI, 3.56–9.44)]. A significant low-risk ratio (RR) of ulcer development and lower limb amputation was detected (P < 0.00001). Lowest RR of ulcer development was detected with tarsal tunnel release [RR, 0.04 (95% CI, 0.00–0.48)]. Improvements in VAS, two-point discrimination, and nerve conduction velocity were nonsignificant in the meta-analysis of five randomized controlled trials (RCTs). The RCT analysis was limited to only two studies for each outcome.

Conclusions:

Meta-analysis of observational studies highlights the efficacy of lower extremity nerve decompression in reducing DPN symptoms, ulcerations, and amputations. Releasing the tibial nerve in the tarsal tunnel region was the most effective observed procedure. Nevertheless, high-quality RCTs are required to support the utility of this intervention in DPN.

Carpal Tunnel Syndrome and Diabetes—A Comprehensive Review

Carpal tunnel syndrome (CTS) is the most common compression neuropathy in the general population and is frequently encountered among individuals with type 1 and 2 diabetes. The reason(s) why a peripheral nerve trunk in individuals with diabetes is more susceptible to nerve compression is still not completely clarified, but both biochemical and structural changes in the peripheral nerve are probably implicated. In particular, individuals with neuropathy, irrespective of aetiology, have a higher risk of peripheral nerve compression disorders, as reflected among individuals with diabetic neuropathy. Diagnosis of CTS in individuals with diabetes should be carefully evaluated; detailed case history, thorough clinical examination, and electrophysiological examination is recommended. Individuals with diabetes and CTS benefit from surgery to the same extent as otherwise healthy individuals with CTS. In the present review, we describe pathophysiological aspects of the nerve compression disorder CTS in relation to diabetes, current data contributing to the explanation of the increased risk for CTS in individuals with diabetes, as well as diagnostic methods, treatment options, and prognosis of CTS in diabetes.

Cost-Effectiveness of Lower Extremity Nerve Decompression Surgery in the Prevention of Ulcers and Amputations: A Markov Analysis

BACKGROUND

The costs and health effects associated with lower extremity complications in diabetes mellitus are an increasing burden to society. In selected patients, lower extremity nerve decompression is able to reduce symptoms of neuropathy and the concomitant risks of diabetic foot ulcers and amputations. To estimate the health and economic effects of this type of surgery, the cost-effectiveness of this intervention compared to current nonsurgical care was studied.

METHODS

To estimate the incremental cost-effectiveness of lower extremity nerve decompression over a 10-year period, a Markov model was developed to simulate the onset and progression of diabetic foot disease in patients with diabetes and neuropathy who underwent lower extremity nerve decompression surgery, compared to a group undergoing current nonsurgical care. Mean survival time, health-related quality of life, presence or risk of lower extremity complications, and in-hospital costs were the outcome measures assessed. Data from the Rotterdam Diabetic Foot Study were used as current care, complemented with information from international studies on the epidemiology of diabetic foot disease, resource use, and costs, to feed the model.

RESULTS

Lower extremity nerve decompression surgery resulted in improved life expectancy (88,369.5 life-years versus 86,513.6 life-years), gain of quality-adjusted life-years (67,652.5 versus 64,082.3), and reduced incidence of foot complications compared to current care (490 versus 1087). The incremental cost-effectiveness analysis was -€59,279.6 per quality-adjusted life-year gained, which is below the Dutch critical threshold of less than €80,000 per quality-adjusted life-year.

CONCLUSIONS

Decompression surgery of lower extremity nerves improves survival, reduces diabetic foot complications, and is cost saving and cost-effective compared with current care, suggesting considerable socioeconomic benefit for society.

Health economic evaluation of different treatment strategies for peripheral entrapment mononeuropathies: a systematic review

Introduction: In this era of cost-conscious health systems, it is of utmost importance to identify and establish the most cost-effective treatment option. However, in the case of peripheral entrapment mononeuropathies there is alack of data regarding economically effective treatment strategies. Therefore, the objective was to conduct an economic evaluation including both costs and benefits of various treatment strategies applied to peripheral entrapment mononeuropathies to estimate the relative cost-effective treatment regimens.Areas covered: Over the 19 years, seven excellent-high quality economic evaluations of three types of peripheral entrapment mononeuropathies were identified in four countries. Our findings showed that surgery was the most cost-effective therapy followed by same cost efficacy of infiltrative therapy and conservative therapy for peripheral entrapment mononeuropathies. However, the fact that surgery was the most common comparator (n = 6) in our selected studies cannot be neglected.Expert opinion: Due to huge methodological variability, the finding of surgery as the cost-effective treatment strategy remains tentative and the decision about the most suitable clinical and cost-effective therapy should be individualized from case to case. Moreover, the economic evaluation of all possible treatment strategies for peripheral entrapment mononeuropathies over alonger period of analysis is required in future studies.

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.

(Cost-)effectiveness of lower extremity nerve decompression surgery in subjects with diabetes: the DeCompression (DECO) trial-study protocol for a randomised controlled trial

INTRODUCTION

The peripheral nerves of patients with diabetes are often pathologically swollen, which results in entrapment at places of anatomical narrowing. This results in nerve dysfunction. Surgical treatment of compression neuropathies in the lower extremities (lower extremity nerve decompression (LEND)) results in relief of symptoms and gain in peripheral nerve function, which may lead to less sensory loss (short term) and less associated detrimental effects including foot ulceration and amputations, and lower costs (long term). The aim of the DeCompression trial is to evaluate the effectiveness and (cost-)effectiveness of surgical decompression of compressed lower extremity nerves (LEND surgery) compared with patients treated with conventional (non-surgical) care.

METHODS AND ANALYSIS

A stratified randomised (1 to 1) controlled trial comparing LEND surgery (intervention) with conventional non-surgical care (control strategy) in subjects with diabetes with problems of neuropathy due to compression neuropathies in the lower extremity. Randomisation is stratified for participating hospital (n=11) and gender. Patients and controls have the same follow-up at 1.5, 3, 6, 9, 12, 18, 24 and 48 months. Participants (n=344) will be recruited in 12 months and enrolled in all affiliated hospitals in which they receive both the intervention or conventional non-surgical care and follow-up. Outcome assessors are blinded to group assignment.

PRIMARY OUTCOME

disease-specific quality of life (Norfolk Quality of Life Questionnaire-Diabetic Neuropathy).

SECONDARY OUTCOMES

health-related quality of life (EuroQoL 5-dimension 5-level (EQ-5D5L), 36-item Short Form (SF-36)), plantar sensation (Rotterdam Diabetic Foot Test Battery), incidence of ulcerations/amputations, resource use and productivity loss (Medical Cost Questionnaire, Productivity Cost Questionnaire) during follow-up. The incremental cost-effectiveness ratio will be estimated on the basis of the collected empirical data and a cost-utility model.

ETHICS AND DISSEMINATION

Ethics approval has been granted by the Medical Research Ethics Committee of Utrecht University Medical Center (reference: NL68312.041.19v5, protocol number: 19-335/M). Dissemination of results will be via journal articles and presentations at national and international conferences.

TRIAL REGISTRATION NUMBER

NetherlandsTrial Registry NL7664.