What's new in the diagnosis and treatment of peripheral nerve entrapment neuropathies

Surgical management of peroneal nerve injuries

BACKGROUND

Traumatic peroneal nerve injuries are typically associated with high-energy injuries. The aim of this study was to evaluate the demographics and outcomes following surgical management of peroneal nerve injuries.

METHODS

Patients evaluated at a single institution with peroneal nerve injuries between 2001 and 2022 were retrospectively reviewed. Mechanism of injury, time to surgery, pre- and postoperative examinations, and operative reports were recorded. Satisfactory outcome, defined as the ability to achieve anti-gravity dorsiflexion strength or stronger following surgery, was compared between nerve grafting and nerve transfers in patients with at least 9 months of postoperative follow-up.

RESULTS

Thirty-seven patients had follow-up greater than 9 months after surgery, with an average follow-up of 3.8 years. Surgeries included neurolysis (n=5), direct repair (n=2), tibial motor nerve fascicle transfer to the anterior tibialis motor branch (n=18), or interposition nerve grafting using sural nerve autograft (n=12). At last follow-up, 59.5% (n=22) of patients had anti-gravity strength or stronger dorsiflexion. Nineteen (51.4%) patients used an ankle-foot orthosis during all or some activities. In patients that underwent nerve grafting only across the peroneal nerve defect, 44.4% (n=4) were able to achieve anti-gravity strength or stronger dorsiflexion. In patients that had a tibial nerve fascicle transfer to the tibialis anterior motor branch of the peroneal nerve, 42.9% (n=6) were able to achieve anti-gravity strength or stronger dorsiflexion at last follow-up. There was no statistical difference between nerve transfers and nerve grafting in postoperative dorsiflexion strength (p = 0.51).

CONCLUSION

Peroneal nerve injuries frequently occur in the setting of knee dislocations and similar high-energy injuries. Nerve surgery is not universally successful in restoration of ankle dorsiflexion, with one-third of patients requiring an ankle-foot orthosis at mid-term follow-up. Patients should be properly counseled on the treatment challenges and variable outcomes following peroneal nerve injuries.

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.

State of the Art and Advances in Peripheral Nerve Surgery

This review is intended to describe and actualize the basic knowledge of the three basic entities that affect the peripheral nerve system and can be treated by surgery: nerve trauma, chronic nerve compressions, and tumors.Regarding trauma, emphasis is given on the timing of surgery, given the fact that the moment in which the surgery is performed and the employed microsurgical reconstruction technique are the most important factors in the final result. Open lesions with associated nerve injury should be managed with an early exploration carried out before 7 days. Closed injuries are usually deferred, with few exceptions, from 3 to 6 months after the trauma.In turn, chronic compressions require an appropriate clinical, neurophysiological, and imaging diagnosis. Isolated sensory symptoms can be treated actively though without surgery: motor signs like atrophy should be regarded as a sign for immediate surgery, as a deferred treatment might cause an irreversible nerve and muscular damage. Endoscopic approaches are a valuable tool for treatment in selected neuropathies.Finally, nerve tumors demand a thorough preoperative evaluation, as benign tumors are treated in a very different way when compared to malignant lesions. Benign tumors can usually be safely and completely resected without sacrificing the nerve of origin. When malignancy is confirmed, extensive resection to optimize patient survival is the main objective, potentially at the expense of neurological function. This may then be followed by adjuvant radiation and/or chemotherapy, depending on the nature of the tumor and the completeness of resection attained. The role of nerve biopsy remains controversial, and several modern diagnostic techniques might be helpful.

The Effectiveness and Safety of Commonly Used Injectates for Ultrasound-Guided Hydrodissection Treatment of Peripheral Nerve Entrapment Syndromes: A Systematic Review

Background: Peripheral nerve entrapment syndromes commonly result in pain, discomfort, and ensuing sensory and motor impairment. Many conservative measures have been proposed as treatment, local injection being one of those measures. Now with high-resolution ultrasound, anatomical details can be visualized allowing diagnosis and more accurate injection treatment. Ultrasound-guided injection technique using a range of injectates to mechanically release and decompress the entrapped nerves has therefore developed called hydrodissection or perineural injection therapy. Several different injectates from normal saline, local anesthetics, corticosteroids, 5% dextrose in water (D5W), and platelet-rich plasma (PRP) are available and present clinical challenges when selecting agents regarding effectiveness and safety.

Aims: To systematically search and summarize the clinical evidence and mechanism of different commonly used injectates for ultrasound-guided hydrodissection entrapment neuropathy treatment.

Methods: Four databases, including PubMed, EMBASE, Scopus, and Cochrane were systematically searched from the inception of the database up to August 22, 2020. Studies evaluating the effectiveness and safety of different commonly used injectates for ultrasound-guided hydrodissection entrapment neuropathy treatment were included. Injectate efficacy presents clinical effects on pain intensity, clinical symptoms/function, and physical performance, electrodiagnostic findings, and nerve cross-sectional areas. Safety outcomes and mechanism of action of each injectate were also described.

Results: From ten ultrasound-guided hydrodissection studies, nine studies were conducted in carpal tunnel syndrome and one study was performed in ulnar neuropathy at the elbow. All studies compared different interventions with different comparisons. Injectates included normal saline, D5W, corticosteroids, local anesthetics, hyaluronidase, and PRP. Five studies investigated PRP or PRP plus splinting comparisons. Both D5W and PRP showed a consistently favorable outcome than those in the control group or corticosteroids. The improved outcomes were also observed in comparison groups using injections with normal saline, local anesthetics, or corticosteroids, or splinting. No serious adverse events were reported. Local steroid injection side effects were reported in only one study.

Conclusion: Ultrasound-guided hydrodissection is a safe and effective treatment for peripheral nerve entrapment. Injectate selection should be considered based on the injectate mechanism, effectiveness, and safety profile.

Surgical intervention for carpal tunnel syndrome in individuals with spinal cord injuries-patient characteristics, diagnostic considerations, and treatment outcomes

STUDY DESIGN

A retrospective chart audit.

OBJECTIVES

To characterize SCI patients with carpal tunnel syndrome (CTS) and evaluate the diagnostic rationale for surgical decision-making.

SETTING

Swiss Paraplegic Centre, Nottwil, Switzerland.

METHODS

Retrospective investigation of medical history, diagnostics, surgeries, and outcomes of surgical treatments of CTS in patients with para- and tetraplegia.

RESULTS

We identified a total of 77 surgeries for CTS in 55 patients: 16 females (25 surgeries) and 39 males (52 surgeries) with spinal cord injury. The majority (47 persons, 68 surgeries) were paraplegic (level of lesion Th2 and below); 8 persons (9 surgeries) were tetraplegic (level of lesion Th1 and above). ASIA scores in the tetraplegic group were A: 0, B: 1, C: 4, D: 3 while complete lesions predominated in the paraplegic group (A: 32, B: 4, C: 5, D: 6). Sixty-six out of 77 patients reported total relief of symptoms. Neither nerve conduction velocity nor motor amplitude correlated well with the severity of CTS. Co-morbidity and specific risk factors were rare.

CONCLUSIONS

SCI patients with CTS respond well to surgical decompression of median nerve regardless of level and type of spinal cord lesion and risk factors. Nerve conduction parameters and clinical findings can provide additional diagnostic support of CTS although nocturnal hand paresthesia, wrist pain at and after loading as well as failed conservative treatment are the main indications for surgical interventions. Based on symptomatology, clinical findings, and nerve conduction studies, we propose a decision-making tree for suggesting surgery or not.

Drop Foot Secondary to a Peroneal Intraneural Ganglion Connected to the Superior Tibiofibular Joint: A Case Report

Peroneal neuropathy is the most frequent mononeuropathy of the lower extremity. Intraneural ganglion cysts (INGCs) are among rare causes of peroneal nerve palsy. According to the articular (synovial) theory, the articular branch plays the key role in the pathogenesis. Patients present with pain around the fibular head and neck, motor weakness resulting in foot drop and paresthesia in the anterolateral calf and foot. Ultrasonography (US) and MRI are both useful in the diagnosis, but MRI is the best imaging modality in the demonstration of the articular connection and the relation of the cyst with adjacent structures, even without special neurography sequences. We present a 32-year-old male patient referred to our neurosurgery clinic with suspicion of lumbar radiculopathy. He presented with right foot drop which began 3 weeks prior. On examination, there was 90% loss in the ankle dorsiflexion and finger extension. Ankle eversion was also weakened. There was no low back or posterolateral thigh pain to suggest L5 radiculopathy and sciatic neuropathy. Following negative lumbar spine MRI, peripheral neuropathy was concerned. Electrodiagnostic evaluations findings were consistent with acute/subacute common peroneal nerve (CPN) axonal neuropathy. Subsequent MRI of knee showed a homogeneous, thin-walled tubular cystic lesion, extending along the course of the CPN and its articular branch. Full recovery of the neuropathy was achieved with early diagnosis and decompression via microsurgical epineurotomy. The diagnosis of INGC was confirmed by histopathologic examination. INGCs, although rare, should also be considered in the differential diagnosis of peripheral mononeuropathies.

Fascial entrapment neuropathy

Entrapment neuropathies are debilitating clinical conditions, creating significant morbidity in the upper and lower extremities in terms of pain, sensory abnormalities, and motor weakness, becoming a challenge to diagnose and treat. Because entrapments can have multiple origins, a misinterpretation of anatomy during examination can lead to incorrect diagnosis and treatment. This review addresses understanding of the anatomy of fascia that can play an important role in this syndrome. There is a specific microenvironment around the nerve composed of connective tissues that include deep fascia, intermuscular septa, epineurium, and perineurium. The microenvironmental modifications can be translated into change in mobility with consequence decreasing of the independency of the nerve from the surrounding structures lading to entrapments and "internal stretch lesion." The entrapments reported in this article reinforce the importance of fascia tissue in generating common symptoms that pose more difficult diagnostic challenges and may often be confused with more common clinical conditions. Clin. Anat. 32:883-890, 2019. © 2019 Wiley Periodicals, Inc.

Dexamethasone versus Hyaluronidase as an Adjuvant to Local Anesthetics in the Ultrasound-guided Hydrodissection of the Median Nerve for the Treatment of Carpal Tunnel Syndrome Patients

Background:

Carpal tunnel syndrome (CTS) is one of the most common focal entrapment neuropathies. Although the exact etiology remains unclear, high-pressure-related intracarpal tunnel compression of the median nerve (MN), progressing ischemia, and mechanical strangulation are common mechanisms. The therapeutic managements for CTS depend on the disease severity, varying from a conservative treatment to surgical interventions. Conservative treatment is helpful for most of the patients with mild-to-moderate CTS. Hydrodissection is a minimally invasive procedure of injecting solutions into some anatomical spaces to facilitate dissection and adhesiolysis. Steroids as an anti-inflammatory drugs are used to treat chronic pain conditions. Hyaluronidase as an adhesolysis agent can also be used for epidural injections with local anesthetics (LAs) and steroids for control of chronic back pain.

Aim of the Study:

This study was carried out to compare the efficacy of hyaluronidase versus dexamethasone as adjuvants to the mixture of LAs in ultrasound (US)-guided hydrodissection of the median nerve in mild to moderate cases of carpal tunnel syndrome.

Settings and Design:

This study was a prospective randomized controlled double-blinded clinical study.

Methods:

40 patients aged from 20 to 60 years old with clinical, electrophysiologic, and ultrasonographic evidence of mild to moderate CTS were included in this study. Each patient was assessed at the baseline (prior to injection) and at 1 week, 1 month, 3 months, and 6 months intervals after injection: (1) The Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) which is a frequently used patient-based questionnaire for measurement of CTS. primary outcome. (2) Median motor and sensory nerve conduction studies (NCS) secondary outcome. (3) Median nerve ultrasonography. The ultrasound examination included measurement of the median nerve cross-sectional area (CSA) at the distal wrist crease (DWC). Also, the median nerve echogenicity, mobility, and vascularity at the DWC were assessed by US. Secondary outcome. All outcome assessments were assessed by single investigator who was blinded to the study details. All patients received US guided hydrodissection of the median nerve at the distal wrist crease. The selected patients were randomly allocated into 2 groups containing 20 patients each according to the study drugs; Group (D) received 5 mL (3 mL plain bupivacaine 0.5% and 2 mL (8 mg) dexamethasone), and Group (H) received 5 mL (3 mL plain bupivacaine 0.5% and 2 mL normal saline containing 300 international units (IU) hyaluronidase. Ultrasound-guided intracarpal injection using ultrasonography (Sono Scape A5; Shinzhen, China) with a 10-18-MHZ linear array transducer was performed by the same physician who was not aware of study groups, the MN was observed at the inlet of the carpal tunnel, 3 ml of solution was injected via the in-plane ulnar approach, to detach the MN from the transverse carpal ligament and an additional 2 ml was injected to separate the MN from underlying flexor tendons. All patients were observed for 30 minutes post injection for possible side effects before discharge. Normally distributed numerical data are presented as mean ± standard deviation, and differences between the groups were compared using the independent Student's t-test. Chi-square test was used for categorical data. Intragroup data at different follow up time points were evaluated using paired Student's t-test. All statistical tests were two-tailed, with P < 0.05 being considered statistically significant.

Results:

The demographic data of the patients in both groups were statistically insignificant (P-value >0.05). In the pre-injection time, there were no statistically significant differences between both groups as regards BCTQ (SSS, FSS), electrophysiological studies (SNCV, DML), and sonographic data (CSA, echogenicity score, mobility score, and vascularity score). The comparison between both groups showed that measured parameters as regards BCTQ (SSS, FSS), electrophysiological studies (SNCV, DML), and sonographic data (CSA, echogenicity score, mobility score, and vascularity score) were significantly improved in group H compared with group D in the follow up periods at 1 week, 1 month, 3 months and 6 months post-injection (P-value <0.05). The comparison within each group showed that in group D, the measured parameters; BCTQ (SSS, FSS), electrophysiological studies (SNCV, DML), and sonographic data (CSA, echogenicity score, mobility score, and vascularity score) were statistically significantly improved at 1 week, 1 month and 3 months follow up post-injection times but they were not significantly improved at 6 months post-injection time compared with the pre-injection data (P-value >0.05). While in group H, these measured parameters were statistically significantly improved in the all follow up post-injection times; at 1 week, 1 month, 3 months and even at 6 months periods compared with the baseline pre-injection data (P-value < 0.05).

Conclusion:

In this study, it was concluded that MN hydrodissction using hyaluronidase (as an adhesolysis agent) significantly improved patients with mild to moderate CTS compared to steroid (as an anti-inflammatory agents) hydrodissection of MN as regards BCTQ (SSS, FSS), electrophysiological studies (SNCV, DML), and sonographic data (CSA, echogenicity score, mobility score, and vascularity score) not only at 1 week, 1 month and 3 months follow up post-injection times but these parameters were also significantly improved at 6 months post-injection time in bupivacaine- hyaluronidase hydrodissection group compared to bupivacaine-steroid hydrodissection group.

A Case of Double Anatomic Variation: Diagnostic Efficacy of Combination of Ultrasound and Neurophysiology

BACKGROUND

The purpose of this paper is to underline that the association of physical examination, electrophysiology, and ultrasound was crucial in identifying the correct disease and atypical characteristics of its presentation, in turn, providing proper information for both surgical treatment and a rehabilitation program. Fibular nerve compression is a common finding in the adult population, and it is more frequent at the fibular head. The clinical picture may be characterized by motor and/or sensory deficits. The same symptoms may sometimes be suggestive of root impairment.

CASE DESCRIPTION

We report the case of a 39-year-old man who came to our laboratory with a diagnosis of multimetameric lumbosacral radiculopathy. The patient reported a history of ankle numbness and transient foot drop. Neurophysiologic examination showed peripheral axonal damage at tibialis anterior and lateral gastrocnemius muscles. A nerve ultrasound showed the presence of a conflict between a fibular exostosis and the fibular nerve. Furthermore, the fibular nerve presented an anatomic variation supplying the lateral gastrocnemius muscle.

CONCLUSIONS

Ultrasound was crucial in recognizing the cause of the atypical presentation and avoiding a misdiagnosis. Also, it allowed the identification of the appropriate treatment and rehabilitation, as well as preventing irreversible nerve damage. As a result, critical information was presented to the surgeon for surgical treatment.

Neurodynamic mobilization in a collegiate long jumper with exercise-induced lateral leg and ankle pain: A case report

STUDY DESIGN

Case Report.

BACKGROUND

The purpose of this case report is to describe nerve mobilization in the treatment of lower extremity neuropathic pain in a female collegiate long jumper.

CASE DESCRIPTION

A 21 year-old long jumper presented 7 months after onset of ankle and leg pain. She complained of "aching" pain over the lateral ankle, radiating proximally to just superior to the lateral knee. Neurodynamic testing of the sural and superficial branch of the fibular nerves was positive. Interventions/Outcomes: Persistent neuropathic pain which impeded sport participation in a collegiate athlete did not improve using traditional rehabilitation intervention, but did ameliorate as a result of an intervention which included self-administered, supervised nerve mobilization of the sural and superficial branch of fibular nerve. The patient improved in all outcome measures including the Lower Extremity Functional Scale (LEFS), Numerical Pain Rating Scale (NPRS), and the Global Rating of Change (GROC).

DISCUSSION

In a female collegiate athlete with persistent neuropathic pain, initial improvements were achieved with traditional rehabilitation, but her pain continued. Considerable additional improvements were achieved following the addition of self-administered, supervised nerve mobilization. Neurodynamic testing should be performed on patients with possible peripheral nerve involvement and treatment commenced if positive.

Piriformis Syndrome and Endoscopic Sciatic Neurolysis

Piriformis syndrome is the compression or the irritation of the sciatic nerve by the adjacent piriformis muscle in the buttock leading to symptoms that include buttock pain, leg pain, and altered neurology in the sciatic nerve distribution. Epidemiological figures of the prevalence are unknown, but are estimated to be about 12.2% to 27%. There is no consensus on the diagnostic criteria. Advancement in magnetic resonance imaging allows us to observe unilateral hyperintensity and bowing of the sciatic nerve. The pathophysiology of the disease includes single blunt trauma, overuse causing piriformis hypertrophy, and long-term microtrauma causing scarring. Treatments include physiotherapy, steroid injections, and surgery. Minimally invasive techniques are emerging with the hope that with less postoperative scar tissue formation, there will be less recurrence of the disease. In this chapter, senior author describes his technique for endoscopic sciatic neurolysis.

Endoscopic Sciatic Neurolysis

Despite remaining a controversial diagnosis, piriformis syndrome continues to affect patients' quality of life with pain, sitting discomfort, and exercise intolerance. Open sciatic neurolysis has been noted by the senior author to often only bring temporary relief of the symptoms, with the recurrence presumably due to postoperative scar tissue. Minimally invasive techniques used to decompress the nerve have met with mixed results. This article describes a step-by-step surgical technique designed to maximize patient safety, as well as surgeon orientation, and achieve a thorough neurolysis. Preoperative findings suggestive of piriformis syndrome are described and include retro-trochanteric pain, sciatica-like leg pain, and paresthesias, as well as a positive response to computed tomography-guided injection of dilute ropivacaine hydrochloride and 40 mg of triamcinolone. The operation is performed with the patient in the lateral decubitus position through 2 portals 6 to 8 cm apart, allowing for good triangulation. Dissection is undertaken with a combination of radiofrequency and a laparoscopic peanut, with the assistance of a vascular sling to control the sciatic nerve. Encouraging results have been achieved, and with increasing interest in this procedure, a step-by-step technical description with an accompanying video may prove useful for other experienced hip arthroscopists. Pearls and pitfalls are discussed.

Exercise-induced leg pain

Exercise-induced leg pain is a common condition in athletes and in people involved in recreational sports. The diagnosis is not always straightforward: many conditions may cause exercise-induced leg pain. The aim of the present review is to provide a complete discussion of the most common pathologies related to this condition. Particular attention is dedicated to the history and the physical examination, which are fundamental for requesting the correct diagnostic tests or imaging techniques necessary for a precise diagnosis.

Peroneal nerve: Normal anatomy and pathologic findings on routine MRI of the knee

Background

Peroneal nerve lesions are not common and are often exclusively assessed clinically and electromyographically.

Methods

On a routine MR examination without dedicated MR-neurography sequences the peroneal nerve can readily be assessed. Axial T1-weighted sequences are especially helpful as they allow a good differentiation between the nerve and the surrounding fat.

Results

The purpose of this article is to review the normal anatomy and pathologic conditions of the peroneal nerve around the knee.

Conclusion

In the first part the variable anatomy of the peroneal nerve around the knee will be emphasized, followed by a discussion of the clinical findings of peroneal neuropathy and general MR signs of denervation. Six anatomical features may predispose to peroneal neuropathy: paucity of epineural tissue, biceps femoris tunnel, bifurcation level, superficial course around the fibula, fibular tunnel and finally the additional nerve branches. In the second part we discuss the different pathologic conditions: accidental and surgical trauma, and intraneural and extraneural compressive lesions.

Teaching Points

• Six anatomical features contribute to the vulnerability of the peroneal nerve around the knee.

• MR signs of muscle denervation within the anterior compartment are important secondary signs for evaluation of the peroneal nerve.

• The most common lesions of the peroneal nerve are traumatic or compressive.

• Intraneural ganglia originate from the proximal tibiofibular joint.

• Axial T1-weighted images are the best sequence to visualise the peroneal nerve on routine MRI.