Lower Extremity Peripheral Nerve Research Articles

High Resolution Ultrasound of the Lower Extremity Nerves

High resolution ultrasound is a powerful diagnostic tool to evaluate the lower extremity peripheral nerves. It offers a complementary evaluation to MR neurography and has distinct advantages. Requests for ultrasound imaging of lower extremity nerves are becoming more commonplace as a first line evaluation of neurologic deficits given its accessibility, lower cost, and non-invasive approach. Radiologists can provide a higher value to their referring providers with a thorough understanding of lower extremity nerve anatomy and common pathologies. This article discusses the ultrasound appearance of lower extremity nerves with an anatomic approach as well as commonly seen pathologies.

Use of corticosteroids for adult chronic pain interventions: sympathetic and peripheral nerve blocks, trigger point injections - guidelines from the American Society of Regional Anesthesia and Pain Medicine, the American Academy of Pain Medicine, the American Society of Interventional Pain Physicians, the International Pain and Spine Intervention Society, and the North American Spine Society

BackgroundThere is potential for adverse events from corticosteroid injections, including increase in blood glucose, decrease in bone mineral density and suppression of the hypothalamic–pituitary axis. Published studies note that doses...

Quantitative assessment of painful diabetic peripheral neuropathy after high-frequency spinal cord stimulation: a pilot study.

Randomized trials have demonstrated efficacy of spinal cord stimulation (SCS) for treatment of painful diabetic neuropathy (PDN). Preliminary data suggested that treatment of PDN with high-frequency SCS resulted in improvements on neurological examination. The purpose of the present study was to explore whether patients with PDN treated with high-frequency SCS would have improvements in lower-extremity peripheral nerve function. Prospective cohort study in an outpatient clinical practice at a tertiary care center. Patients with PDN were treated with high-frequency SCS and followed up for 12 months after SCS implantation with clinical outcomes assessments of pain intensity, neuropathic symptoms, and neurological function. Small-fiber sudomotor function was assessed with the quantitative sudomotor axon reflex test (QSART), and large-fiber function was assessed with nerve conduction studies (NCS). Lower-extremity perfusion was assessed with laser Doppler flowmetry. Nine patients completed 12-month follow-up visits and were observed to have improvements in lower-extremity pain, weakness, and positive sensory symptoms. Neuropathy impairment scores were improved, and 2 patients had recovery of sensory responses on NCS. A reduction in sweat volume on QSART was observed in the proximal leg but not at other sites. No significant differences were noted in lower-extremity perfusion or NCS as compared with baseline. The improvement in pain relief was concordant with improvement in neuropathy symptoms. The findings from this study provide encouraging preliminary data in support of the hypothesis of a positive effect of SCS on peripheral neuropathy, but the findings are based on small numbers and require further evaluation. ClinicalTrials.gov ID NCT03769675.

Efficacy of Liposomal Bupivacaine in Managing Postoperative Pain in Foot and Ankle Surgeries: A Prospective Randomized Blinded Controlled Study

Category: Hindfoot; Midfoot/Forefoot Introduction/Purpose: Surgeons’ response to the nationwide opioid epidemic has included using alternatives to narcotic pain medications. Regional anesthesia has provided options to reduce narcotic consumption after surgery. Liposomal Bupivacaine (LB) is not FDA approved for use in nerve blocks in the lower extremity, though it is approved for more dangerous blocks (interscalene for example) in the upper extremity. The literature on LB in foot and ankle surgery has been limited to local infiltration and no major study has explored its efficacy when used in lower extremity peripheral nerve blocks. In this study, we compare local LB infiltration with LB used in peripheral nerve blocks in the lower extremity and compare both of these techniques with the current standard of care, a non-LB peripheral nerve block. Methods: All patients undergoing surgery in a single surgeon foot and ankle practice were enrolled in this IRB approved, prospective, randomized controlled study. Patients having surgery between January 2022 – January 2023 were randomized to one of three study arms: Group 1 Anesthesia administered ultrasound guided nerve block with local anesthetic only, Group 2 Anesthesia administered ultrasound guided nerve block with LB/local only mix, or Group 3 Surgeon administered infiltrative field block with LB/local mix. The primary outcomes collected included the amount of narcotic pain medication required in the PACU, oral morphine equivalents (OME) up to postoperative day 4 and after postoperative day 4, subjective duration of nerve block, and patient reported outcomes (PROMIS Pain Interference/Depression/Physical Function). Collection was obtained via chart review from hospital EMR, and phone calls made to patients during specific time intervals after surgery. Analysis was performed utilizing GraphPad Prism (Ver 9.0, GraphPad Software, San Diego CA USA). Results: After exclusion of 110 patients, 248 patients met inclusion criteria. Ninety-eight underwent perineural popliteal or popliteal adductor block with LB/local mix, 70 underwent popliteal or popliteal adductor block with local only (Group 2), 80 underwent surgeon administered local field block with LB/local mix (Group 3). Median PACU morphine equivalents required for pain control were significantly lower in Groups 1 and 2 (0 OME) compared to local field block (7.5 OME) (p < 0.05). Median OME utilized up to POD 4 and median OME utilized after POD 4 were both significantly lower in the LB/local mix perineural block group (p < 0.05) compared to Groups 2 and 3. Duration of block effect was significantly higher in the LB/local mix group compared to Groups 2 and 3 (p < 0.05). Conclusion: Preoperative perineural blocks containing a mix of LB and local anesthetic significantly reduce PACU, early postoperative, and mid postoperative narcotic use of patients undergoing outpatient foot and ankle surgery. The duration of effect of perineural block is significantly extended with addition of LB to the block mixture. Consideration should be given to the use of LB blocks in foot and ankle surgical procedures to reduce patient postoperative narcotic requirements.

Peripheral nerve involvement in hereditary spastic paraplegia characterized by quantitative magnetic resonance neurography.

Hereditary spastic paraplegias (HSPs) are heterogenous genetic disorders. While peripheral nerve involvement is frequent in spastic paraplegia 7 (SPG7), the evidence of peripheral nerve involvement in SPG4 is more controversial. We aimed to characterize lower extremity peripheral nerve involvement in SPG4 and SPG7 by quantitative magnetic resonance neurography (MRN). Twenty-six HSP patients carrying either the SPG4 or SPG7 mutation and 26 age-/sex-matched healthy controls prospectively underwent high-resolution MRN with large coverage of the sciatic and tibial nerve. Dual-echo turbo-spin-echo sequences with spectral fat-saturation were utilized for T2-relaxometry and morphometric quantification, while two gradient-echo sequences with and without an off-resonance saturation rapid frequency pulse were applied for magnetization transfer contrast (MTC) imaging. HSP patients additionally underwent detailed neurologic and electroneurographic assessments. All microstructural (proton spin density [ρ], T2-relaxation time, magnetization transfer ratio) and morphometric (cross-sectional area) quantitative MRN markers were decreased in SPG4 and SPG7 indicating chronic axonopathy. ρ was superior in differentiating subgroups and identifying subclinical nerve damage in SPG4 and SPG7 without neurophysiologic signs of polyneuropathy. MRN markers correlated well with clinical scores and electroneurographic results. MRN characterizes peripheral nerve involvement in SPG4 and SPG7 as a neuropathy with predominant axonal loss. Evidence of peripheral nerve involvement in SPG4 and SPG7, even without electroneurographically manifest polyneuropathy, and the good correlation of MRN markers with clinical measures of disease progression, challenge the traditional view of the existence of HSPs with isolated pyramidal signs and suggest MRN markers as potential progression biomarkers in HSP.

Lower extremity peripheral nerve pathology: Utility of preoperative ultrasound-guided needle localization before operative intervention.

Historically, the use of ultrasound (US) in the management of peripheral nervous system (PNS) pathology has been limited to diagnostic confirmation or guidance for interventional injections. This technical case series will demonstrate the utility and versatility of preoperative US-guided needle localization for the excision of lower extremity neuromas and other pathology of the PNS. Five patients with symptomatic lower extremity PNS tumors were retrospectively reviewed. This case series corroborates the technical nuances of localizing lower extremity neuromas by US-guided needle and wire placement prior to operative excision. This was achieved by a multidisciplinary team that included plastic surgery, neurosurgery, and radiology. Five patients had US-guided needle localization of a lower extremity PNS target prior to operative intervention. Three patients had lower extremity neuromas of varying origins, including the lateral femoral cutaneous nerve (LFCN), saphenous nerve, and sural nerve. The remaining two patients had a sciatic nerve sheath Schwannoma and a femoral nerve glomus tumor. Under sonographic visualization, a needle was advanced to the target perimeter and withdrawn, leaving behind a percutaneous guidewire. This technique simplified the marking of the nerve course prior to dissection and led to efficient intraoperative identification of all five PNS tumors without any complications. Preoperative US-guided needle localization led to safe, accurate, and efficient perioperative and intraoperative identification of neuromas and other PNS tumors of the lower extremity prior to excision. By reducing the challenges of nerve identification in a scarred tissue bed, this multidisciplinary approach may decrease postoperative patient morbidity.

Association of patient characteristics with the receipt of regional anesthesia

BackgroundRegional anesthesia (RA) may improve patient-related outcomes, including decreased operative complications, shortened recovery times, and lower hospital readmission rates. More analyses are needed using a diverse set of databases to...

Advances in lower extremity peripheral nerve surgery

Peripheral nerve injury (PNI) is a common source of pain and disability in patients. While many patients are affected by PNI, peripheral nerve surgery advancements in the lower extremity have lagged behind the upper extremity. Subsequently, principles that have demonstrated success in the upper extremity have been implemented in the lower extremity. Interventions with recent advances include the advent of novel nerve transfers in the lower extremity and using stem cells and electrical stimulation (ES) for nerve regeneration. This article focuses on advances in nerve transfers for lower extremity PNI and provides details on the basic science and clinical applications of newer interventions.

Association of Lower Extremity Peripheral Nerve Impairment and the Risk of Dementia: Bringing the Peripheral Nervous System Closer to Center.

Association of Lower Extremity Peripheral Nerve Impairment and the Risk of Dementia: Bringing the Peripheral Nervous System Closer to Center.

Contemporary Approaches to Peripheral Nerve Surgery.

"State of the Art" Learning Objectives: This manuscript serves to provide the reader with a general overview of the contemporary approaches to peripheral nerve reconstruction as the field has undergone considerable advancement over the last 3 decades. The learning objectives are as follows: To provide the reader with a brief history of peripheral nerve surgery and some of the landmark developments that allow for current peripheral nerve care practices.To outline the considerations and management options for the care of patients with brachial plexopathy, spinal cord injury, and lower extremity peripheral nerve injury.Highlight contemporary surgical techniques to address terminal neuroma and phantom limb pain.Review progressive and future procedures in peripheral nerve care, such as supercharge end-to-side nerve transfers.Discuss rehabilitation techniques for peripheral nerve care.

Regional anesthesia for acute and subacute orthopedic trauma: A review

• Multimodal pain control has become the standard of care for management of orthopedic trauma. • This paper describes use of regional aesthesia for surgical intervention of extremity fractures in patients who present following traumatic injury as part of a multimodal pain management protocol. • Types of, indications for, and outcomes of both upper and lower extremity peripheral nerve blocks will be reviewed. Pain management in the setting of acute and subacute orthopedic trauma can be challenging. Due to the recent focus on the rising opioid epidemic, as well as the adverse side of effects of opioid pain medication, multimodal pain control has become the standard of care for management of orthopedic trauma, particularly during operative fixation. The purpose of this paper is to report on the use of regional anesthesia for surgical intervention of extremity fractures in patients who present following traumatic injury as part of a multimodal pain management protocol. Types of, indications for, and outcomes of both upper and lower extremity peripheral nerve blocks will be reviewed.

Myoclonus and tremor in chronic inflammatory demyelinating polyneuropathy: a multichannel electromyography analysis.

Information regarding involuntary movements in chronic inflammatory polyneuropathy (CIDP) is gradually increasing. Our goal is to identify the types of involuntary movements in CIDP. All patients who were followed with the diagnosis of CIDP were invited for clinical and electrophysiological evaluations. Demographic and clinical findings (age, gender, duration of illness, diagnosis, treatments) were noted. Clinical examination and multichannel surface electromyography were done. We also performed routine upper and lower extremity peripheral nerve conduction studies, F-waves, long latency reflexes, blink reflex, mixed nerve silent period and cutaneous silent period in all patients. Twenty-two patients accepted the invitation. Eleven patients with CIDP had involuntary movements. Ten (45.5%) patients with CIDP had tremor and seven (31.8%) had short-duration and high-amplitude myoclonus. Regarding demographic, clinical and electrophysiological features, there was no significant difference between patients with and without tremor. The latencies of R1, R2 and R2c components of BR were longer among CIDP patients without tremor compared to CIDP patients with tremor. Presence of myoclonus (p = 0.007) and delayed F-waves (p = 0.008) were associated with the presence of tremor. Tremor and myoclonus were frequent in CIDP. The fact that myoclonus was detected in the majority of patients only by multichannel surface EMG who were clinically evaluated as pure tremor suggests that a more detailed electrophysiological evaluation is required. There was no difference in the medications used or other clinical features between patients with and without tremor.

Quantitative magnetic resonance neurographic characterization of peripheral nerve involvement in manifest and pre-ataxic spinocerebellar ataxia type 3.

Knowledge about the exact underlying pathophysiological changes involved in the genesis and progression of spinocerebellar ataxia type 3 (SCA3) is limited. Lower extremity peripheral nerve lesions in clinically, genetically and electrophysiologically classified ataxic and pre-ataxic SCA3mutation carriers were characterized and quantified by magnetic resonance neurography (MRN). Eighteen SCA3mutation carriers and 20 age-/sex-matched healthy controls were prospectively enrolled. All SCA3mutation carriers underwent detailed neurological and electrophysiological examinations. 3 T MRN covered the lumbosacral plexus and proximal thigh to the tibiotalar joint by using T2-weighted inversion recovery sequences, dual-echo relaxometry sequences with spectral fat saturation, and two gradient-echo sequences with and without an off-resonance saturation rapid frequency pulse. Detailed quantification of nerve lesions by morphometric and microstructural MRN markers, including T2 relaxometry and magnetization transfer contrast imaging, was conducted in all study participants. MRN detected peripheral nerve damage in ataxic and pre-ataxic SCA3. The quantitative markers proton spin density (ρ), T2 relaxation time, magnetization transfer ratio and cross-sectional area were decreased in SCA3, indicating chronic axonopathy. MTR and ρ identified early, subclinical nerve damage in pre-ataxic SCA3 and in SCA3mutation carriers without polyneuropathy and were superior in differentiating between all subgroups. Additionally, microstructural markers correlated well with clinical symptom scores and electrophysiological results. Our data provide a comprehensive characterization of peripheral nerve damage in SCA3 and assist in understanding the mechanisms of the multisystemic disease evolution. Evidence of peripheral nerve involvement prior to the onset of clinically overt ataxia might have important implications for designing early intervention studies.

Associations of Lower Extremity Peripheral Nerve Impairment and Risk of Dementia in Black and White Older Adults.

Peripheral nerve impairments and dementia are common among older adults and share risk factors. However, few studies have examined whether peripheral nerve function and dementia are associated. We evaluated whether lower extremity peripheral nerve impairments were associated with higher incidence of dementia and whether associations differed by comorbidity subgroups (diabetes, low vitamin B12, and APOE ε4 allele carriers). We studied Black and White Health, Aging, and Body Composition Study participants 70 to 79 years of age and without dementia at enrollment. Lower extremity sensory and motor peripheral nerve function was measured at year 4 (the analytic baseline of this study). Sensory nerve impairments were measured with monofilament (1.4 g, 10 g) and vibration threshold of the toe. Monofilament insensitivity was defined as unable to detect monofilament (3 of 4 touches), and vibration detection impairment was defined as >130 μm. Fibular motor impairments were defined as <1 mV compound motor action potential (CMAP) amplitude and slow nerve conduction velocity <40 m/s. Incident dementia over the following 11 years was determined from medical records, cognitive scores, and medications. Cox proportional hazard models adjusted for demographics and health conditions assessed associations of nerve impairments with incident dementia. Among 2,174 participants (52% women, 35% Black), 45% could not detect monofilament 1.4 g, 9% could not detect monofilament 10 g, 6% could not feel vibration, 10% had low CMAP amplitude, and 24% had slow conduction velocity. Monofilament 10 g (hazard ratio [HR] 1.35, 95% CI 0.99-1.84) and vibration detection insensitivity (HR 1.73, 95% CI 1.24-2.40) were associated/borderline associated with a higher risk of dementia after covariate adjustment. Estimates were elevated but not significant for monofilament 1.4 g, CMAP amplitude, and conduction velocity (p > 0.05). Increasing number of peripheral nerve impairments was associated with higher risk of dementia in a graded fashion; for ≥3 impairments, the HR was 2.37 (95% CI 1.29-4.38). In subgroup analyses, effect estimates were generally higher among those with diabetes, low vitamin B12, and APOE ε4 allele except for vibration detection. Peripheral nerve impairments, especially sensory, were associated with a higher risk of dementia even after adjustment for age and other health factors. These associations may represent a shared susceptibility to nervous system degeneration.

Association of Lower Extremity Peripheral Nerve Impairment and the Risk of Dementia

Evidence is emerging that lower extremity peripheral nerve impairments are associated with and may even precede dementia. This has been demonstrated clinically: slowed walking speed1 and poor gait2 have been shown to predict dementia, and motor and sensory impairments have been associated with Alzheimer disease.3 Although the mechanisms linking the peripheral nervous system to dementia are unclear, pathogenic factors support the relationship. A typical pattern of peripheral neuropathy sensory loss (distal, bilateral, symmetrical) has been described in the elderly.4 This pattern is thought to be due to loss of energy production in the cell bodies in the dorsal root ganglia as a result of metabolic, toxic, and neurodegenerative etiologies. In addition, neurodegenerative proteins have been found in the dorsal root ganglia,5,6 suggesting that the same process that occurs in brain neurons in the CNS is also occurring in the peripheral nervous system.

Regional anesthesia for orthopedic procedures: What orthopedic surgeons need to know.

Regional anesthesia is an integral component of successful orthopedic surgery. Neuraxial anesthesia is commonly used for surgical anesthesia while peripheral nerve blocks are often used for postoperative analgesia. Patient evaluation for regional anesthesia should include neurological, pulmonary, cardiovascular, and hematological assessments. Neuraxial blocks include spinal, epidural, and combined spinal epidural. Upper extremity peripheral nerve blocks include interscalene, supraclavicular, infraclavicular, and axillary. Lower extremity peripheral nerve blocks include femoral nerve block, saphenous nerve block, sciatic nerve block, iPACK block, ankle block and lumbar plexus block. The choice of regional anesthesia is a unanimous decision made by the surgeon, the anesthesiologist, and the patient based on a risk-benefit assessment. The choice of the regional block depends on patient cooperation, patient positing, operative structures, operative manipulation, tourniquet use and the impact of post-operative motor blockade on initiation of physical therapy. Regional anesthesia is safe but has an inherent risk of failure and a relatively low incidence of complications such as local anesthetic systemic toxicity (LAST), nerve injury, falls, hematoma, infection and allergic reactions. Ultrasound should be used for regional anesthesia procedures to improve the efficacy and minimize complications. LAST treatment guidelines and rescue medications (intralipid) should be readily available during the regional anesthesia administration.

Impact of anatomical variations on ultrasonographic reference values of lower extremity peripheral nerves.

Cross-sectional area (CSA) reference values using ultrasonography vary widely for lower extremity peripheral nerves. In addition, there is a lack of data on the muscular branches of the tibial nerve and the anatomical variations of the sural nerve. We aimed to evaluate the ultrasonographic reference values for lower extremity peripheral nerves considering different anatomical variations and physical factors. The CSA of the lower extremity nerve was measured at 10 sites. In addition to establishing reference values, differences in the CSA owing to anatomical variations were verified. The relationship between CSA and physical factors, such as age, height, weight, body mass index, and ankle circumference, was also examined. A total of 100 healthy Japanese volunteers were recruited. The mean CSA of the sural nerve significantly differed depending on its formation pattern (1.4-1.8 mm2 ). The mean decreases in CSAs from the proximal to distal tibial and fibular nerves within the popliteal region significantly differed based on the fine branching pattern. The maximum value of the mean decreases in CSAs in the tibial and fibular nerves reached 7.2 and 2.5 mm2 , respectively. With respect to physical factors, age and ankle circumferences were associated with CSA at several measurement sites. Fine branching from the tibial and fibular nerves and sural nerve formation may affect CSA measurements. The establishment of accurate CSA reference values requires consideration of anatomical variations in the peripheral nerves of the lower extremity.

POPLITEAL CYSTIC SCHWANNOMA MIMICKING BAKER CYST – AN UNUSUAL CASE PRESENTATION – CASE REPORT

Introduction: Schwannoma is the most common tumor of peripheral nerves. They are usually solitary, encapsulated, homogenous slow growing masses, sometimes associated with pain and paresthesia.We present a case of schwannoma in an unusual location. Case presentation: A 16 year old boy presented to surgical OPD with a slow growing left popliteal swelling for 6 months and neuralgia for 1 month. The swelling decreasing on knee exion. Based on clinical suspicion patient was operated for popliteal cyst. Intraoperatively there was close association with nerve and it was difcult to dissect from nerve. So it was thought of being a nerve tumor. Surgical excision was done. Histopathological examination revealed it to be Cystic Schwannoma. Discussion: Schwannoma is the most common benign neoplasm of peripheral nerves. Cystic degeneration and repeated hemorrhages (10%) can occur sometimes. There are two types of tissues in Schwannoma – Antoni A and Antoni B.Schwannoma varies from 2-20 cm in diameter. It is not localized to any specic area; it can occur anywhere along peripheral nervous system in neck, mediastinum, retroperitoneum, pelvis, upper extremities. It is extremely unusual in lower limb of which tibial nerve is uncommon site. Conclusion: Diagnosis of schwannoma originating from lower extremity peripheral nerves may be delayed because it can be misdiagnosed as Baker's Cyst or the symptoms of the patient can be thought as a result of lumbar disc herniation.Thorough clinical examination and investigations, conrms the diagnosis, as management is different for both.

Rating Peripheral Nerves of the Lower Extremities Using the AMA Guides, Sixth Edition

Abstract Nerve lesions caused by traumatic events to the lower extremity's peripheral nerves are rated using Section 16.4 of the sixth edition of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides). Results from sensory and motor nerve tests are used to assign the impairment class within Table 16-12, Peripheral Nerve Impairment (6th ed, 534). The default rating may be modified with the functional history and clinical studies modifiers, but not the physical examination modifier, because it is used to assign the impairment class and define the degree of neurologic severity. Impairment for both sensory and motor deficits are assigned and then combined at the lower extremity level.

Lower extremity regional anesthesia: essentials of our current understanding

The advent of ultrasound guidance has led to a renewed interest in regional anesthesia of the lower limb. In keeping with the American Society of Regional Anesthesia and Pain Medicine’s...