Ultrasound as a Useful Tool for a Peripheral Nerve Surgeon: Examples in Clinical Practice.

BACKGROUND: Peripheral nerve surgeons often require additional imaging for examination, diagnostic testing, and preoperative planning. Point-of-care ultrasound (US) is a cost-effective, accessible, and well-established technique that can assist the surgeon in diagnosing and treating select peripheral nerve pathologies. With this knowledge, the properly trained surgeon may perform US-guided nerve blocks to help accurately diagnose and treat causes of neuropathic pain. We offer this paper, not as an exhaustive review, but as a selection of various peripheral nerve pathologies, which the senior author treats, and their associated US examination findings. Our goal is to encourage other peripheral nerve surgeons to incorporate US into their practices. METHODS: We provide various cases from our outpatient peripheral nerve clinic demonstrating relevant US anatomy. We also review techniques for US guided nerve blocks with relevant anatomic landmarks. RESULTS: US imaging successfully assisted in identification and injection techniques for various peripheral nerve pathologies in a surgeon's practice. Examples were presented from the neck, trunk, upper extremity, and lower extremity. CONCLUSION: Our review highlights the use of US by a peripheral nerve surgeon in an outpatient private practice clinic to diagnose and treat select peripheral nerve pathologies. We encourage reconstructive surgeons to add US to their arsenal of diagnostic tools.

Complex regional pain syndrome patient treated with a below knee amputation, implanting nerves directly into muscle: A case report.

Persistent, disabling lower extremity pain, outside the distribution of a single nerve, is termed chronic regional pain syndrome (CRPS), but, in reality, this chronic pain is often due to multiple peripheral nerve injuries. It is the purpose of this report to describe the first application of the "traditional," nerve implantation into muscle, usually used in the treatment of a painful neuroma, as a pre-emptive surgical technique in doing a below knee amputation (BKA). In 2011, a 51-year-old woman developed severe, disabling CRPS, after a series of operations to treat an enchondroma of the left fifth metatarsal. When appropriate peripheral nerve surgeries failed to relieve distal pain, a BKA was elected. The approach to the BKA included implantation of each transected peripheral nerve directly into an adjacent muscle. At 5.0 years after the patient's BKA, the woman reported full use of this extremity, using the prosthesis, and was free of phantom limb and residual limb pain. This anecdotal experience gives insight that long-term relief of lower extremity CRPS can be achieved by a traditional BKA utilizing the approach of implanting each transected nerve into an adjacent muscle.

Re-visiting post-breast surgery pain syndrome: risk factors, peripheral nerve associations and clinical implications.

Aesthetic and reconstructive breast surgery is among the most common operations performed by plastic surgeons. The prevalence of persistent pain after breast surgery remains underappreciated by plastic surgeons. Post breast surgery pain syndrome (PBSPS) is reported to range between 20-60%. It is the purpose of this paper to revisit chronic pain as a combination of the breast intervention and relate this to the peripheral nerve(s) transmitting the pain message, in order to understand the underlying etiology and to improve breast pain treatment outcomes.

Two-Team Surgical Approach to Improve Retroperitoneal Nerve Identification in the Treatment of Groin Pain.

BACKGROUND: An estimated 700,000 groin hernia repairs are performed in the United States each year. Studies have shown that up to 50% of patients who undergo groin hernia repair are affected by persistent pain beyond the first few days after surgery. At 2 to 5 years after either open or laparoscopic, mesh or without mesh, 10% to 12% of these patients will have persistent and disabling pain. If the ilioinguinal, iliohypogastric, or genitofemoral nerves are injured below the transversalis muscle layer, the traditional external, open approach to nerve resection will not help these patients. The traditional internal, laparoscopic, approach to the retroperitoneum can be used for nerve resection, but identification of the correct nerve is difficult. Therefore, we have developed a 2-team, dual approach, combining open and endoscopic approaches to solve this problem. METHODS: A retrospective review of the electronic medical records was performed to identify all patients who underwent a dual approach for groin denervation after persistent postherniorraphy pain. This dual approach included an external incision paired with a laparoscopic, retroperitoneal approach to identify and/or transect the ilioinguinal, iliohypogastic, lateral femoral cutaneous, and genital branch of the genitofemoral nerve. Inclusion criteria are persistent groin pain with alleviation after preoperative nerve block and either a failed attempt at an external approach groin denervation or pain after a primary laparotomy/laparoscopy procedure. RESULTS: Thirteen patients met the inclusion criteria. All patients underwent a dual approach, and nerves were identified and confirmed in both the external groin and laparoscopic approaches. When placed on a scale from excellent/good to fair/poor relief of pain, 10 patients (77%) described excellent/good relief and 3 (23%) continued to have persistent pain. CONCLUSIONS: A combined open surgical procedure, to identify the lateral femoral cutaneous nerve, and a laparoscopic procedure in the retroperitoneum have demonstrated the feasibility of this approach to identify correctly the nerve to be resected to relieve disabling groin pain.

Diagnostic Accuracy of Selective 3-T MR Neurography-guided Retroperitoneal Genitofemoral Nerve Blocks for the Diagnosis of Genitofemoral Neuralgia.

Purpose To determine if 3-T magnetic resonance (MR) neurography-guided retroperitoneal genitofemoral nerve (GFN) blocks are safe and effective for the diagnosis of genitofemoral neuralgia. Materials and Methods Following institutional review board approval and informed consent, 26 subjects (16 men, 10 women; mean age, 42 years [range, 24-78 years]; mean body mass index, 28 kg/m2 [range, 20-35 kg/m2]) with intractable groin pain were included. By using a 3-T MR imaging system, intermediate-weighted turbo spin-echo pulse sequences, and MR-conditional needles, diagnostic MR neurography-guided GFN blocks were performed in the retroperitoneum. Outcome variables included technical success, procedure time, complications, and rates of positive and negative GFN blocks in association with therapeutic outcomes. For the assessment of a learning curve, Mann-Whitney test was used. P values ≤ .05 were considered to indicate a statistically significant difference. Results In 26 subjects, 30 retroperitoneal GFN blocks were performed. Twelve (40%) were performed with an anterior needle path, 12 (40%) with a lateral needle path, and six (20%) with a posterior needle path. GFN blocks were technically successful in 24 of 26 (92%) subjects, achieving appropriate scrotal anesthesia. No complications occurred. The time required for a GFN block was 40 minutes (range, 18-67 minutes). The rate of a successful GFN intervention after a positive GFN block was 88% (14 of 16). The rate of a successful intervention of an alternative target after a negative GFN block was 71% (five of seven). Conclusion Selective retroperitoneally directed MR neurography-guided GFN blocks are safe and effective with high technical success and positive effect on surgical decision making in patients with presumed genitofemoral neuralgia. © RSNA, 2017 Online supplemental material is available for this article.

Pain after breast surgery: Etiology, diagnosis, and definitive management.

BACKGROUND: Breast procedures are among the most common surgeries performed by Plastic Surgeons. The prevalence of persistent pain remains unknown. Our experience has been that persistent breast pain is often related to intercostal nerve trauma. The purpose of this article was to increase awareness of this problem while describing the diagnostic and management strategies for patients with post-operative breast pain. METHODS: A retrospective review of 10 patients with breast pain was stratified according to the index surgical procedures: implant-based reconstruction (7), breast reduction (1), breast augmentation (1), and mastopexy (1). Outcomes were assessed with a numerical analog score. Physical examination demonstrated painful trigger points along the pathway of one or more intercostal nerves. Prior to surgery, each patient improved ≥5 points after a diagnostic Xylocaine/Marcaine local anesthesia block of the suspected intercostal nerves. At surgery, one or more intercostal nerves were resected and implanted into adjacent muscles. RESULTS: At a mean of 16.5 months, there were six excellent, one good, and three poor self-reported results. Intercostal nerves resected included the intercostal-brachial (5 patients), 3rd (7 patients), 4th (8 patients), 5th (9 patients), 6th (7 patients), and 7th (1 patient). Multiple intercostal nerves were resected as follows: 3 nerves (4 patients), 4 nerves (1 patient), 5 nerves (3 patients), 6 nerves (1 patient), and 8 nerves (1 patient). CONCLUSIONS: Intercostal neuromas can be the source of breast pain following breast surgery. The same clinical and diagnostic approach used for upper and lower extremity neuroma pain can be used in patients with breast pain. © 2016 Wiley Periodicals, Inc. Microsurgery 36:535-538, 2016.

3-Tesla High-Field Magnetic Resonance Neurography for Guiding Nerve Blocks and Its Role in Pain Management.

Interventional magnetic resonance (MR) neurography is a minimally invasive technique that affords targeting of small nerves in challenging areas of the human body for highly accurate nerve blocks and perineural injections. This cross-sectional technique uniquely combines high tissue contrast and high-spatial-resolution anatomic detail, which enables the precise identification and selective targeting of peripheral nerves, accurate needle guidance and navigation of the needle tip within the immediate vicinity of a nerve, as well as direct visualization of the injected drug for the assessment of appropriate drug distribution and documentation of the absence of spread to confounding nearby nerves.

Rectal pain of neural origin: resection of sensory rectal branches of pudendal nerve.

BACKGROUND: A neural origin should be considered in the differential diagnosis of rectal pain if the onset of the pain is in relationship to previous surgery on the anus or rectum. STUDY DESIGN: A retrospective cohort was identified by computer search of office files from May 2010 to December 2012. Seven patients, two males, and five females, were identified who have been treated surgically for complaints of isolated rectal pain arising from coloproctectomy in three patients (inflammatory bowel disease) and after hemorrhoidectomy in three patients and one patient with mesh placed for urinary incontinence. Patient's mean age was 52.5 years. Mean duration of pain was 29.9 months (range, 9-120 months). Diagnosis was demonstrated by an anesthetic block of the pudendal nerve. Surgical approach was excision of rectal sensory branches of the pudendal nerve in the ischiorectal fossa and implantation of these nerves into the gluteus maximus muscle. RESULTS: Outcome data are available, with a mean follow-up of 17.7 months (range, 13-30 months). Of the three coloproctectomy patients, two are considered excellent results and one a poor result. All three of the hemorrhoidectomy patients are excellent results. The one patient who had the mesh placement for urinary incontinence required two attempts to remove all sensory rectal branches and then achieved excellent pain relief. CONCLUSION: Chronic rectal pain should be considered to have a pudendal neural origin after previous anal/rectal surgery. Resection of all rectal sensory branches can give excellent and lasting relief of pain.

High-resolution magnetic resonance neurography in upper extremity neuropathy.

The most common sites of nerve entrapment are in the upper extremity, commonly diagnosed based on clinical findings and electrophysiologic studies. Cross-sectional imaging modalities, such as ultrasonography and magnetic resonance (MR) imaging, have been used to enhance diagnostic accuracy and provide anatomic mapping of abnormalities. MR neurography offers multiplanar high-resolution imaging of upper extremity nerves as well as adjacent soft tissues, and provides an objective assessment of the neuromuscular anatomy and related abnormalities. This article reviews the normal 3-T MR neurographic appearance of the upper extremity nerves, and abnormal findings related to injury, entrapment, and other pathologic conditions.

High-resolution 3-T MR neurography of the lumbosacral plexus.

The lumbosacral plexus comprises a network of nerves that provide motor and sensory innervation to most structures of the pelvis and lower extremities. It is susceptible to various traumatic, inflammatory, metabolic, and neoplastic processes that may lead to lumbrosacral plexopathy, a serious and often disabling condition whose course and prognosis largely depend on the identification and cure of the causative condition. Whereas diagnosis of lumbrosacral plexopathy has traditionally relied on patients' medical history, clinical examination, and electrodiagnostic tests, magnetic resonance (MR) neurography plays an increasingly prominent role in noninvasive characterization of the type, location, and extent of lumbrosacral plexus involvement and is developing into a useful diagnostic tool that substantially affects disease management. With use of 3-T MR imagers, improved coils, and advanced imaging sequences, which provide exquisite spatial resolution and soft-tissue contrast, MR neurography provides excellent depiction of the lumbrosacral plexus and its peripheral branches and may be used to confirm a diagnosis of lumbrosacral plexopathy with high accuracy or provide superior anatomic information should surgical intervention be necessary.

Meralgia paresthetica: 3-Tesla magnetic resonance neurography.

OBJECTIVE: To assess the diagnostic accuracy and observer performance of 3-Tesla magnetic resonance neurography (MRN) in the evaluation of meralgia paresthetica (MP). MATERIALS AND METHODS: Two independent readers were blinded to the clinical diagnosis and evaluated the MRN studies of the pelvis of 11 patients with MP and 28 control participants. In each study, the lateral femoral cutaneous nerves were assessed for signal alteration and/or neuroma formation, indicating lateral femoral cutaneous neuropathy, at various levels along their course. Intra- and inter-observer reliability was evaluated. RESULTS: Both readers exhibited substantial intraobserver agreement in detecting signal alterations and neuroma formation of the lateral femoral cutaneous nerve (LFCN). The readers demonstrated moderate interobserver agreement in detecting signal alteration of the LFCN and poor interobserver agreement in diagnosing neuroma formation. Sensitivity, specificity, positive predictive value, and negative predictive value of LFCN neuropathy diagnosis were ≥ 71 % and ≥ 94 % for both readers respectively. The diagnostic test accuracy was ≥ 90 % for both readers. CONCLUSION: 3-Tesla MRN provides reliable and accurate diagnostic evaluation of meralgia paresthetica.

High-resolution magnetic resonance-guided posterior femoral cutaneous nerve blocks.

OBJECTIVE: To assess the feasibility, technical success, and effectiveness of high-resolution magnetic resonance (MR)-guided posterior femoral cutaneous nerve (PFCN) blocks. MATERIALS AND METHODS: A retrospective analysis of 12 posterior femoral cutaneous nerve blocks in 8 patients [6 (75%) female, 2 (25%) male; mean age, 47 years; range, 42-84 years] with chronic perineal pain suggesting PFCN neuropathy was performed. Procedures were performed with a clinical wide-bore 1.5-T MR imaging system. High-resolution MR imaging was utilized for visualization and targeting of the PFCN. Commercially available, MR-compatible 20-G needles were used for drug delivery. Variables assessed were technical success (defined as injectant surrounding the targeted PFCN on post-intervention MR images) effectiveness, (defined as post-interventional regional anesthesia of the target area innervation downstream from the posterior femoral cutaneous nerve block), rate of complications, and length of procedure time. RESULTS: MR-guided PFCN injections were technically successful in 12/12 cases (100%) with uniform perineural distribution of the injectant. All blocks were effective and resulted in post-interventional regional anesthesia of the expected areas (12/12, 100%). No complications occurred during the procedure or during follow-up. The average total procedure time was 45 min (30-70) min. CONCLUSIONS: Our initial results demonstrate that this technique of selective MR-guided PFCN blocks is feasible and suggest high technical success and effectiveness. Larger studies are needed to confirm our initial results.

3T magnetic resonance neurography of tibial nerve pathologies.

Diagnosis of tibial neuropathy has been traditionally based on clinical examination and electrodiagnostic studies; however, cross-sectional imaging modalities have been used to increase the diagnostic accuracy and provide anatomic mapping of the abnormalities. In this context, magnetic resonance neurography (MRN) offers high-resolution imaging of the tibial nerve (TN), its branches and the adjacent soft tissues, and provides an objective assessment of the neuromuscular anatomy, abnormality, and the surrounding pathology. This review describes the pathologies affecting the TN and illustrates their respective 3 Tesla (T) MRN appearances with relevant case examples.

Magnetic resonance neurography of common peroneal (fibular) neuropathy.

OBJECTIVE: To examine diagnostic accuracy of semiquantitative and qualitative magnetic resonance neurography criteria in common peroneal nerve (CPN) neuropathy. MATERIALS AND METHODS: Institutional review board approval was obtained with a waiver of informed consent for this Health Insurance Portability and Accountability Act-compliant retrospective study. A review of 28 knees in 28 subjects (12 males and 16 females; age range, 13-84 years; mean [SD] age, 42 [20] years) who had undergone magnetic resonance neurography of the knee was performed. Thirteen patients who had a final diagnosis of CPN were classified as cases, and 15 patients who lacked a final diagnosis of CPN neuropathy were classified as controls. Morphological characteristics of the CPN, including nerve T2 signal intensity, nerve size, nerve course, fascicles morphology, regional muscle edema, and fatty infiltration, and an overall assessment of the CPN as being normal or abnormal were evaluated by 2 independent radiologists blinded to the clinical history. Overall sensitivity, specificity, and accuracy compared against our reference standards were expressed as percentages. Interobserver agreements were assessed using linear weighted κ statistics. RESULTS: Common peroneal nerve T2 signal abnormality had the highest sensitivity (77%) in identifying CPN neuropathy. Except for T2 signal abnormality, overall specificity for the nerve morphological parameters and muscle denervation change assessed was fairly high, ranging from 94% to 100%. The consensus accuracy ranged from 68% to 79% for the morphological characteristics assessed. The interobserver reproducibility was very good (k = 0.90 to 0.91) for assessment of regional muscle denervation changes and moderate (k = 0.46 to 0.59) for morphological CPN characteristics. CONCLUSION: Magnetic resonance neurography is a useful modality in supplementing the diagnosis of CPN. Using predefined classification criteria helps standardize the morphological criteria of CPN neuropathy diagnosis.

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 positive Tinel sign as predictor of pain relief or sensory recovery after decompression of chronic tibial nerve compression in patients with diabetic neuropathy.

Predictive ability of a positive Tinel sign over the tibial nerve in the tarsal was evaluated as a prognostic sign in determining sensory outcomes after distal tibial neurolysis in diabetics with chronic nerve compression at this location. Outcomes were evaluated with a visual analog score (VAS) for pain and measurements of the cutaneous pressure threshold/two-point discrimination. A multicenter prospective study enrolled 628 patients who had a positive Tinel sign. Of these patients, 465 (74%) had VAS >5. Each patient had a release of the tarsal tunnel and a neurolysis of the medial and lateral plantar and calcaneal tunnels. Subsequent, contralateral, identical surgery was done in 211 of the patients (152 of which had a VAS >5). Mean VAS score decreased from 8.5 to 2.0 (p <0.001) at 6 months, and remained at this level for 3.5 years. Sensibility improved from a loss of protective sensation to recovery of some two-point discrimination during this same time period. It is concluded that a positive Tinel sign over the tibial nerve at the tarsal tunnel in a diabetic patient with chronic nerve compression at this location predicts significant relief of pain and improvement in plantar sensibility.

The sympathetic innervation of the human foot.

BACKGROUND: The sympathetic innervation of the hand was demonstrated using formaldehyde staining techniques in the 1990s and provides a basis for both medical (botulinum toxin type A) and surgical (sympathectomy) therapeutic approaches. This research investigates the sympathetic innervation of the human foot using tyrosine hydroxylase immunohistochemistry. METHODS: With institutional review board approval, six freshly amputated lower extremities had arterial, venous, and peripheral nerve biopsies obtained at the distal leg, ankle, and forefoot levels. Tibial, peroneal, sural, and saphenous nerves were processed immediately for immunohistochemical staining using an anti-tyrosine hydroxylase antibody, for light and electron microscopy evaluation. Qualitative assessments noted the presence or absence of tyrosine hydroxylase-positive fibers in artery, vein, and peripheral nerve. Within the nerve, location of the tyrosine hydroxylase staining was noted. RESULTS: The presence of tyrosine hydroxylase-positive material was identified in each artery, vein, and nerve examined at each level of the foot and ankle. For the artery, the staining was in the adventitia, and rarely in the media of the vessel wall. There were clear entry points into the artery from the connective tissue. For the vein, the staining was more evenly distributed but to a lesser intensity than in the artery. Within each nerve at the proximal levels, the staining was diffusely throughout the fascicles, with clear sites of fibers leaving the periphery. CONCLUSIONS: It is concluded that (1) sympathetic innervation of the foot arrives along each peripheral nerve, (2) the vessels already contain sympathetic innervation at the level of the ankle, and (3) the sympathetic innervation of the foot is extensive.

High resolution imaging of tunnels by magnetic resonance neurography.

Peripheral nerves often traverse confined fibro-osseous and fibro-muscular tunnels in the extremities, where they are particularly vulnerable to entrapment and compressive neuropathy. This gives rise to various tunnel syndromes, characterized by distinct patterns of muscular weakness and sensory deficits. This article focuses on several upper and lower extremity tunnels, in which direct visualization of the normal and abnormal nerve in question is possible with high resolution 3T MR neurography (MRN). MRN can also serve as a useful adjunct to clinical and electrophysiologic exams by discriminating adhesive lesions (perineural scar) from compressive lesions (such as tumor, ganglion, hypertrophic callous, or anomalous muscles) responsible for symptoms, thereby guiding appropriate treatment.

Soleal sling syndrome (proximal tibial nerve compression): results of surgical decompression.

BACKGROUND: Although distal tibial nerve compression is well recognized, proximal tibial nerve compression remains a rarely recognized clinical condition. This report defines the presentation, diagnosis, surgical decompression technique, and clinical outcome of neurolysis of the tibial nerve at this soleal sling compression site. METHODS: Forty-nine patients with 69 proximal tibial nerves (20 bilateral) were stratified retrospectively into three groups: neuropathy (n = 10), failed tarsal tunnel syndrome (n = 25), and trauma (n = 14). Pain level, strength of the flexor hallucis longus muscle, neurosensory testing of the hallux, and subjective sensory improvement were evaluated. Each proximal tibial nerve compression was subjected to neurolysis with division of the soleal sling. RESULTS: Results were stratified into poor, fair, good, and excellent based on the amount of pain relief and improvement in motor and sensory function. In all groups combined, there were 13 excellent (26.5 percent), 13 good (26.5 percent), 18 fair (36.7 percent), and five poor (10.2 percent) results. Results in the neuropathy group were excellent in two patients, good in three, fair in four, and poor in one (mean follow-up, 18.7 months). Results in the failed tarsal tunnel syndrome group were excellent in two, good in six, fair in 13, and poor in four patients (mean follow-up, 13.9 months). The trauma subgroup had the best outcomes: excellent in nine patients, good in four, fair in one, and poor in zero (mean follow-up, 13.4 months). CONCLUSION: Regardless of cause, if a proximal tibial nerve compression beneath the soleal sling is identified, neurolysis may improve pain and sensory and motor function. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

High-resolution 3-T MR neurography of peroneal neuropathy.

The common peroneal nerve (CPN), a major terminal branch of the sciatic nerve, can be subject to a variety of pathologies, which may affect the nerve at any level from the lumbar plexus to its distal branches. Although the diagnosis of peripheral neuropathy is traditionally based on a patient's clinical findings and electrodiagnostic tests, magnetic resonance neurography (MRN) is gaining an increasing role in the definition of the type, site, and extent of peripheral nerve disorders. Current high-field MR scanners enable high-resolution and excellent soft-tissue contrast imaging of peripheral nerves. In the lower extremities, MR neurography has been employed in the demonstration of the anatomy and pathology of the CPN, as well as in the detection of associated secondary muscle denervation changes. This article reviews the normal appearance of the CPN as well as typical pathologies and abnormal findings at 3.0-T MR neurography of the lower extremity.