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.

Assessment of Distal Motor Latency of the Femoral Nerve in Clinically Healthy Adult Dogs.

This study aimed to evaluate femoral nerve latency time recorded from both vastus lateralis and vastus medialis muscles, in clinically healthy dogs. Eighteen adult dogs were distributed into 2 distinct body mass ranges (Group 1: 1-4.1 kg, n= 9; Group 2: 4.2-13 kg, n= 8), according to the median body mass (4.1 kg). Distal motor latencies for the femoral nerve were obtained in right- and left hind limbs. Platinum surface electrodes were used to record the latency of femoral nerve from the vastus lateralis muscle, whereas coaxial needle electrodes were used to record the latency from the vastus medialis muscle. The distal motor nerve latencies were 1.52 ± .23 milliseconds and 1.69 ± .42 milliseconds, respectively, for vastus lateralis and vastus medialis muscles. There were no significant differences of distal motor nerve latencies between vastus lateralis and vastus medialis muscles. Hind limb length of Group 1 was significant shorter than Group 2. There were no significant differences of latencies between Groups 1 and 2. No significant correlations were observed between latency and body mass, and between latency and hind limb length for dogs of both groups. In conclusion, the femoral motor latency measurement was easy to obtain and may supply additional data in the examination of diseases that affect the hind limbs. Latency values of vastus lateralis longer than 1.52 ± .23 milliseconds in small/medium-sized breeds may be considered as suggestive of a femoral neuropathy.

Extraneural findings during peripheral nerve ultrasound: Prevalence and further assessment.

INTRODUCTION: In this study we evaluated the frequency and further assessment of extraneural findings encountered during peripheral nerve ultrasound (US). METHODS: Our retrospective review identified 278 peripheral nerve US examinations of 229 patients performed between December 2014 and December 2015. Reports were reviewed to assess the number of studies without peripheral nerve abnormalities and the frequency and further assessment of extraneural findings. RESULTS: A total of 107 peripheral nerve US examinations of 90 patients (49 men and 41 women, mean age 55 ± 16 years) did not report peripheral nerve abnormalities. Extraneural findings were observed in 24 of 107 (22.4%) studies. Fifteen of the 278 [5.4% (95% confidence interval 2.7%-8.1%)] studies led to a recommendation for additional imaging or clinical evaluation of an extraneural finding. DISCUSSION: At least 5.4% (15 of 278) of peripheral nerve US studies led to additional clinical or imaging assessment. Muscle Nerve 57: 65-69, 2018.

Use of Central Motor Conduction Time and Spinal Cord Evoked Potentials in the Electrophysiological Assessment of Compressive Cervical Myelopathy.

STUDY DESIGN: A retrospective study. OBJECTIVE: This study investigated the pathophysiology of compressive cervical myelopathy (CCM) with prolonged central motor conduction time (CMCT) in the upper limbs (ULs) rather than lower limbs (LLs) and prolonged CMCT at the thoracic level (TL). SUMMARY OF BACKGROUND DATA: Earlier reports indicated the usefulness of CMCT to assess preoperative CCM severity. However, little information exists on patients with prolonged CMCT-UL rather than CMCT-LL and prolonged CMCT-TL. METHODS: Ninety-four patients (61 men, 33 women; age 28-87 years) with CCM who underwent cervical laminoplasty participated. Fifty-three volunteers provided normal data on CMCT-UL and LL. CMCT-TL was calculated as CMCT-LL - CMCT-UL. We defined three groups: group U, prolonged CMCT-UL rather than CMCT-LL (n = 14); group E, prolonged CMCT-UL and CMCT-LL equality (n = 43); and group L, prolonged CMCT-TL (n = 37). We evaluated intraoperative recording of spinal cord evoked potentials (SCEPs), neurological findings, and surgical outcomes. RESULTS: Control mean CMCT-UL was 5.2 ±â€Š0.7 ms, CMCT-LL was 11.8 ±â€Š1.1 ms, and CMCT-TL was 6.6 ±â€Š1.2 ms. SCEPs results were significantly different between CCM patients in group U and L (P < 0.01). Almost all patients in three groups showed hyperreflexia of the patellar tendon reflex, but great toe position sense was abnormal in most patients in group L only. Japanese Orthopedics Association (JOA) scores improved postoperatively in all patients. There was a significant difference in recovery rate of the JOA score between group L and other groups (both P < 0.05). CONCLUSION: Multimodal SCEPs, clinical findings, and surgical outcomes showed that patients with CCM and prolonged CMCT-TL had substantial disorders of the gray matter, lateral corticospinal tract, and posterior funiculus. Spine surgeons should be aware that prognosis may be poor even after surgery in patients with severe myelopathy such as prolonged CMCT-TL. LEVEL OF EVIDENCE: 4.

Balance and mobility assessment for ruling-out the peripheral neuropathy of the lower limbs in older adults.

The peripheral neuropathy of the lower limbs (PNLL) is an important cause of balance and mobility impairment in older adults. The nerve conduction study (NCS) is the gold standard for PNLL diagnosis. Aim of this work is to establish the sensitivity (Sn) and the specificity (Sp) of the balance and mobility examination for the PNLL in older adults. This study consecutively recruited 72 participants (>65years) who accessed to the clinical neurophysiology outpatient clinic for suspected PNLL. Participants were given the NCS and four clinical tests. Mobility was evaluated by the Timed Up and Go (TUG) test, the Performance Oriented Mobility Assessment (POMA) and the de Morton Mobility Index (DEMMI). In addition the Clinical Evaluation of Static Upright Stance (CELSIUS) scale was developed for a selective evaluation of static balance. Based on the NCS, 36% of participants had PNLL. The CELSIUS scale (cutoff: 19.5/24), the TUG test (cutoff: 9.6s) and the DEMMI scale (cutoff: 17.5/19) have high Sn (0.92÷0.96), but low Sp (0.28÷0.43) for the PNLL in the older adult. POMA scale (cutoff: 14.5/16) has low Sn (0.73), but acceptable Sp (0.85). In addition, CELSIUS, DEMMI and TUG negative likelihood ratios are 0.13, 0.17 and 0.12, respectively. Balance and mobility examination have high sensitivity for PNLL. CELSIUS score>19/24, DEMMI score>17/19 or TUG time≤9.6s substantially reduce PNLL likelihood. These clinical measures are thus recommended for ruling-out PNLL in the older adult.

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.

Nonoperative treatment for lumbosacral radiculopathy: what factors predict treatment failure?

BACKGROUND: Prior studies of nonoperative treatment for lumbosacral radiculopathy have identified potential predictors of treatment failure, defined by persistent pain, persistent disability, lack of recovery, or subsequent surgery. However, few predictors have been replicated, with the exception of higher leg pain intensity, as a predictor of subsequent surgery. QUESTIONS/PURPOSES: We asked two research questions: (1) Does higher baseline leg pain intensity predict subsequent lumbar surgery? (2) Can other previously identified "candidate" predictors of nonoperative treatment failure be replicated? METHODS: Between January 2008 and March 2009, 154 participants with acute lumbosacral radicular pain were enrolled in a prospective database; 128 participants (83%) received nonoperative treatment and 26 (17%) received surgery over 2-year followup. Ninety-four nonoperative participants (73%) responded to followup questionnaires. We examined associations between previously identified "candidate" predictors and treatment failure defined as (1) subsequent surgery; (2) persistent leg pain on a visual analog scale; (3) persistent disability on the Oswestry Disability Index; or (4) participant-reported lack of recovery over 2-year followup. Confounding variables including sociodemographics, clinical factors, and imaging characteristics were evaluated using an exploratory bivariate analysis followed by a multivariate analysis. RESULTS: With the numbers available, higher baseline leg pain intensity was not an independent predictor of subsequent surgery (adjusted odds ratio [aOR], 1.22 per point of baseline leg pain; 95% confidence interval [CI], 0.98-1.53; p = 0.08). Prior low back pain (aOR, 4.79; 95% CI, 1.01-22.7; p = 0.05) and a positive straight leg raise test (aOR, 4.38; 95% CI, 1.60-11.9; p = 0.004) predicted subsequent surgery. Workers compensation claims predicted persistent leg pain (aOR, 9.04; 95% CI, 1.01-81; p = 0.05) and disability (aOR, 5.99; 95% CI, 1.09-32.7; p = 0.04). Female sex predicted persistent disability (aOR, 3.16; 95% CI, 1.03-9.69; p = 0.05) and perceived lack of recovery (aOR, 2.44; 95% CI, 1.02-5.84; p = 0.05). CONCLUSIONS: Higher baseline leg pain intensity was not confirmed as a predictor of subsequent surgery. However, the directionality of the association seen was consistent with prior reports, suggesting Type II error as a possible explanation; larger studies are needed to further examine this relationship. Clinicians should be aware of potential factors that may predict nonoperative treatment failure, including prior low back pain or a positive straight leg raise test as predictors of subsequent surgery, workers compensation claims as predictors of persistent leg pain and disability, and female sex as a predictor of persistent disability and lack of recovery. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Effects of anesthesia versus regional nerve block on major leg amputation mortality rate.

There are greater than 120,000 above-knee amputations (AKA) and below-knee amputations (BKA) performed in the USA each year. Traditionally, general anesthesia (GA) was the preferred modality of anesthesia. The use of regional nerve blocks has recently gained popularity, however, without the supporting evidence of any mortality benefits. Our objective was to evaluate whether regional nerve blocks yield significant mortality reduction in major lower-extremity amputations. Retrospective data of both AKA and BKA procedures at the Maimonides Medical Center from 2005 to 2009 were analyzed. Patients received either general sedation, spinal or ultrasound-guided regional nerve blocks as per decision of the attending anesthesiologist. Regional nerve blocks for major lower-extremity amputations consisted of femoral, sciatic, saphenous and popliteal nerve blocks. A retrospective inquiry of 30-day mortality was performed with reference to the Social Security Death Index and hospital records. One hundred and fifty-eight patients were included in the study (82 men and 86 women with mean age of 74.5 years ± 12.9 SD, range of 33-98 years) of which 46 patients had regional nerve blocks and 112 had GA or spinal blocks. Patients who received both regional blocks and GA/spinal blocks within 30 days were excluded. The overall 30-day mortality was 17.1% (27 patients) consisting of 15.2% for regional nerve analgesia versus 17.9% for GA/spinal blocks (P = 0.867). Age did not affect mortality outcome in either groups of anesthesia modality. Our analysis did not reveal any mortality benefit of utilizing regional nerve block over GA or spinal blocks.

A large animal survival model (Sus scrofa) of extremity ischemia/reperfusion and neuromuscular outcomes assessment: a pilot study.

BACKGROUND: Extremity ischemia/reperfusion has been studied mostly in small-animal models with limited characterization of neuromuscular or functional outcome. The objective of this experiment was to report a large-animal survival model of extremity ischemia/reperfusion using circulating, electromyographic (EMG), gate, and histologic measures of injury and limb recovery. METHODS: Sus scrofa swine (n = 6; mean, 83 kg) were randomized to iliac artery occlusion for 0 (control), 1 (1 HR), 3 (3 HR), or 6 (6 HR) hours. Restoration of flow after a standard large-vessel reconstructive technique (thrombectomy, heparin irrigation, and patch angioplasty) was performed in each of the control, 1HR, 3HR, and 6HR animals, whereas one animal had iliac artery segment excision with no restoration (NR) of axial flow. One animal had operative exposure but no intervention on the iliac artery (sham). Animals were recovered and closely monitored for 2 weeks. Indicators of ischemia/reperfusion and functional recovery, including circulating markers, EMG measures (complex motor action potential), and Tarlov gate scoring (0-4; 0, insensate/paralyzed to 4, normal posture and no gait abnormality) were measured at 24 hours and 72 hours and 7 days and 14 days. Muscle (peroneus) and nerve (peroneal) were collected during necropsy at 14 days to assess gross and histologic changes. Duplex ultrasound was performed serially during the recovery period to confirm patency of vascular reconstruction. RESULTS: There were no deaths or failures of vascular reconstruction. Control had a Tarlov score of 4 and normal EMG measures at each point during recovery (same as sham). Tarlov scores at 1, 3, and 14 days recovery in each of the animals were as follows: 1HR: 3, 3, and 4; 3HR: 1, 2, and 4; 6HR: 1, 2, and 3; and NR: 1, 2, and 4. Complex motor action potential as a percentage of baseline at 1, 2, and 14 days recovery was as follows: 1HR: 56%, 55%, and 84%; 3HR: 9%, 8%, and 57%; 6HR: 5%, 5%, and 16%; and NR: 22%, 28%, and 33%. Muscle and nerve histology was the same in sham, control, and 1HR animals. Moderate degeneration and necrosis was observed in peroneus muscle of the 3HR animals. The peroneal nerve in 3HR demonstrated minimal Wallerian degeneration. Severe necrosis was present, as was minimal regeneration, and peroneal nerve demonstrated moderate Wallerian degeneration in 6HR. CONCLUSION: This study reports a new large-animal survival model of extremity ischemia/reperfusion using circulating, functional, and histologic markers of neuromuscular recovery. Findings provide insight into an extremity ischemic threshold after which functional neuromuscular recovery is lost. Additional study is necessary to define this threshold and factors that may move it to a more or less favorable position in the setting of extremity injury.

The ASRA evidence-based medicine assessment of ultrasound-guided regional anesthesia and pain medicine: Executive summary.

OBJECTIVES: The American Society of Regional Anesthesia and Pain Medicine charged an expert panel to examine the evidence basis for ultrasound guidance as a nerve localization tool in the clinical practices of regional anesthesia and interventional pain medicine. METHODS: The panel searched, examined, and assessed the literature of ultrasound-guided regional anesthesia (UGRA) from the past 20 years. The qualities of studies were graded using the Jadad score. Strength of evidence and recommendations were graded using an accepted rating tool. RESULTS: The panel made specific literature-based assessments concerning the relative advantages and limitations of UGRA relative to traditional nerve localization methods as they pertained to block characteristics and complications. Assessments and recommendations were made for upper and lower extremity, neuraxial, and truncal blocks and include pediatrics and interventional pain medicine. CONCLUSIONS: Ultrasound guidance improves block characteristics (particularly performance time and surrogate measures of success) that are often block specific and that may impart an efficiency advantage depending on individual practitioner circumstances. Evidence for UGRA impacting patient safety is currently limited to the demonstration of improvements in the frequency of surrogate events for serious complications.

Ultrasound guidance in peripheral regional anesthesia: philosophy, evidence-based medicine, and techniques.

PURPOSE OF REVIEW: This article introduces the use of ultrasound to facilitate peripheral regional anesthesia. RECENT FINDINGS: Regional anesthesia, despite its well known clinical benefits, has not gained the popularity of general anesthesia. This is secondary to multiple shortcomings including a defined failure rate, lack of simplicity, and the potential for patient discomfort or injury. Many of the negative aspects of regional anesthesia evolve from the reality that current nerve-localization techniques are unreliable. Given the great variation in human anatomy it is not surprising that even the most veteran clinician can be challenged by techniques that demand anatomical assumptions. The recent use of ultrasound imaging for nerve localization is an innovative application of an old technology which addresses many of the shortcomings of current techniques. Specifically, ultrasound imaging allows the operator to see neural structures, guide the needle under real-time visualization, navigate away from sensitive anatomy, and monitor the spread of local anesthetic. SUMMARY: Ultrasound technology represents an ideal mechanism by which the regional anesthesiologist can attain the safety, speed, and efficacy of general anesthesia. Ultimately, it is the correct peri-neural spread of local anesthetic around a nerve that provides safe, effective, and efficient anesthetic conditions.

Assessment of lower extremity nerve block: reprise of the Four P's acronym.

BACKGROUND AND OBJECTIVES: Successful performance of lower-extremity regional anesthesia includes sensory and/or motor block assessment of up to 4 major peripheral nerves. This brief report describes a methodology for the rapid evaluation of lower-extremity anesthesia before surgical incision. METHODS: Illustrations highlight the techniques for evaluation of sciatic, obturator, lateral femoral cutaneous, and femoral nerve anesthesia. This methodology is based on a Four P's acronym: push, pull, pinch, punt. CONCLUSIONS: Accurate assessment of lower-extremity regional anesthesia can be achieved rapidly using The Four Ps evaluation tool.