Anterior interosseous nerve and posterior interosseous nerve involvement in neuralgic amyotrophy

Unraveling the mysteries of parsonage turner syndrome: A journey towards optimal management. A systematic review

Aims

Parsonage Turner Syndrome (PTS) is a peripheral neuropathy manifesting as sudden onset pain, muscle weakness, and atrophy. This review aims to analyse long-term outcomes reported in adult patients with PTS, and establish an optimised management approach.

Methods

A comprehensive literature search was performed using MEDLINE, PubMed, and the Cochrane Library. Articles that met the eligibility criteria were included. Analysis on time to presentation, presentation, interventions and long-term functional outcomes was conducted. All relevant information was collected by two independent reviewers.

Results

Twenty-five studies, comprising 950 PTS patients, were identified. Patients averaged 43.8 years in age, with a F:M ratio of 0.6:1, and presented symptoms spanning 1-24 months prior to seeking medical attention. Management details were elucidated for 402 patients (42 ​%), with 87 ​% managed conservatively. Among conservatively managed patients, over 50 ​% exhibited no improvement. 62/402 (15 ​%) necessitated surgical interventions, including neurolysis, decompression, nerve transfers, and diaphragmatic plication. 25/31 (80.6 ​%) neurolysis cases demonstrated full functional recovery, including pain resolution and full muscle strength, between 1 day and 13 months (average 2.9 months). 2 nerve transfer cases achieved full forward flexion at 2.5 months. Overall, long-term outcomes of PTS, reported at 5-25 months, revealed residual neuropathic pain in 60 ​% and incomplete motor function return in 70 ​% of patients.

Conclusions

PTS recognition and referral challenges persist, impeding timely management. While surgical interventions are advocated after three months for incomplete recovery, long-term surgical outcomes are inadequately reported. An optimal surgical strategy for stagnant nerve recovery needs to be devised for this challenging cohort of patients.

Clinical characteristics and results after conservative treatment or interfascicular neurolysis of 100 limbs with spontaneous anterior interosseous nerve palsy: A prospective Japanese multicenter study

BACKGROUND

Spontaneous anterior interosseous nerve (AIN) palsy is characterized by the sudden onset of upper limb pain followed by weakness of muscles mainly innervated by the AIN. Although this palsy is conventionally treated conservatively, interfascicular neurolysis to release hourglass-like fascicular constrictions has been recommended. The present study aimed to establish the clinical characteristics and treatment strategy for this condition.

METHODS

One hundred limbs with spontaneous AIN palsy from 24 Japanese institutions were treated either conservatively or with interfascicular neurolysis according to the patient's intention. Patients were followed periodically from 3 months to either recovery or ≥36 months after onset. Limbs recovering to manual muscle testing grade 4 or better in both the flexor pollicis longus and flexor digitorum profundus of the index finger were rated as Good recovery, with all other results classified as Poor recovery. We performed logistic regression analysis to determine the independent factors associated with Good recovery.

RESULTS

Good recovery was achieved in 39 of 49 limbs treated conservatively and 44 of 51 limbs by interfascicular neurolysis. All 26 limbs with conservative treatment displaying ≥1 grade of manual muscle testing improvement within 6 months after onset achieved Good recovery. All 23 limbs with Group I palsy, in which weakness was recognized only in muscles innervated by the AIN, obtained Good recovery with interfascicular neurolysis regardless of when it was performed. In the 59 limbs with no recovery at 6 months by conservative treatment, Good recovery was achieved in 30 of 36 limbs by subsequent interfascicular neurolysis and 13 of 23 limbs continuing conservative treatment. In these 59 limbs, interfascicular neurolysis and Group I palsy were significantly associated with Good recovery.

CONCLUSIONS

Conservative treatment is recommended within 6 months following symptom onset, after which time interfascicular neurolysis is advisable for cases of no improvement.

Isolated Radial Nerve Palsy in a Newborn Due to a Congenital Myofibroma: A Rare Case of Peripheral Nerve Injury

Isolated musculoskeletal infantile myofibroma is a rare tumor of pediatric age. The majority of cases are seen in children under two years old, but it can occur at any age as a painless enlarging mass that involves bone, skin, or soft tissue, typically accompanied by compression symptoms. Perineural involvement is extremely rare in myofibromas. Neurological impairment can occur during infancy but isolated nerve palsy, particularly in peripheral nerves within the upper extremity, is very uncommon. Neonatal radial nerve palsy is a rare entity caused by different conditions. Among these, we mention local tumors affecting peripheral nerves, such as myofibroma. There are few cases described in the literature, which mainly concern adult patients. The authors present a case of congenital isolated radial nerve palsy in a newborn with MF of the right elbow, which resulted in impairment of the wrist and finger extension. Following a six-month monitoring period, the patient underwent surgical treatment to restore function to his right wrist and hand. This involved excising the infiltrated radial nerve segment associated with palliative surgery. Despite the benignity of this lesion, severe nerve damage and perineural involvement may require surgical treatment with nerve resection and reconstruction.

Nerve Torsion as a Pattern of Parsonage-Turner Syndrome: Literature Review and Two Representative Cases

(1) Background: Parsonage-Turner Syndrome (PTS) is a rare peripheral nerve disease characterized by different degrees of nerve impairment. The recent development of nerve ultrasound has enabled the use of new data in the diagnosis of the disease. The aim of this study is to conduct a literature review about the ultrasound evaluation of PTS and present two clinical cases that are characteristic of the disease. (2) Methods: A review of the literature from the last 10 years on the topic containing data regarding nerve ultrasound was performed. In addition, two cases of patients on whom nerve ultrasound was performed at the first evaluation and at follow-up after the indicated treatment were described. (3) Results: The results of our review show that although it is defined as plexopathy, PTS is most often a form of multifocal neuropathy. We also report the most frequently used ultrasound classification and possible prognostic correlations and report our experience with the description of two paradigmatic clinical cases. (4) Conclusions: Further studies are needed to understand the true prognostic power of each degree of nerve impairment and the possible implications in clinical practice regarding treatment indications.

Diagnostic Considerations in Compressive Neuropathies

Peripheral nerve compression of the upper extremity is a common pathology often necessitating surgical intervention, much is known, but much more is left to understand. For the more common pathologies, carpal tunnel syndrome, cubital tunnel syndrome, and ulnar tunnel syndrome, research and clinical efforts directed toward standardization and reduction of resource use have been attempted with varied success. Diagnosis of many of these syndromes is largely based on a proper history and physical examination. Electrodiagnostic studies continue to have value, but proportionally less than previous decades. In addition, emerging technologies, including magnetic resonance neurography, novel ultrasound evaluation techniques, and ultrasound-guided diagnostic injections, are beginning to demonstrate their ability to add value to the diagnostic algorithm, particularly when less common compressive neuropathies are present and/or the diagnosis is in question.

Anterior interosseous nerve syndrome following infection with COVID-19: a case report

BACKGROUND

Various neurological manifestations associated with coronavirus disease 2019 have been increasingly reported. Herein, we report a rare case of anterior interosseous nerve syndrome, which occurred 5 days after the onset of coronavirus disease 2019.

CASE PRESENTATION

A 62-year-old Asian woman with a history of coronavirus disease 2019 who developed a complete motor deficit in the left flexor pollicis longus and pronator quadratus without sensory deficits. The symptoms appeared as a sudden onset fatigue and severe pain of the left arm, 5 days after the onset of coronavirus disease 2019. She noticed paralysis of the left thumb at 2 weeks after the onset of coronavirus disease 2019. Electromyography assessment of the anterior interosseous nerve-dominated muscles revealed neurogenic changes such as positive sharp wave and fibrillation in flexor pollicis longus and pronator quadratus, confirming the diagnosis of anterior interosseous nerve syndrome. There were no other diseases that could have resulted in peripheral nerve palsy. We performed a functional reconstruction surgery of the thumb by tendon transfer from the extensor carpi radialis longus to the flexor pollicis longus. The patient reported a good patient-reported outcome (2.27 points in QuickDASH Disability/Symptom scoring and 5 points in Hand20 scoring) at final follow-up (1 year after the surgery).

CONCLUSION

This case highlights the need for vigilance regarding the possible development of anterior interosseous nerve syndrome in patients with coronavirus disease 2019. Tendon transfer from extensor carpi radialis longus to flexor pollicis longus can provide good functional recovery for unrecovered motor paralysis after anterior interosseous nerve syndrome.

Anterior Interosseous Nerve Syndrome

Anterior interosseous nerve syndrome (AINS) is a rare form of peripheral neuropathy which involves disruption of the anterior interosseous nerve. The pathophysiology of AINS remains unclear. AINS typically initially presents with forearm pain and may gradually progress to palsy of the deep muscles of the anterior forearm. Diagnosis of AINS requires thorough patient history and physical exam. EMG is the preferred diagnostic study and classically reveals abnormal activity and prolonged latency periods within the evoked action potentials of the FPL and PQ. Due to the self-limiting nature of AINS, there is general agreement that conservative and symptomatic management should be explored for up to 6 months as first line therapy, which usually includes analgesics and nonsteroidal anti-inflammatory drugs, contracture prevention, hand therapy, and hand splinting. Surgical options such as internal neurolysis and minimally invasive endoscopic decompression may be explored if functional recovery from conservative management is limited.

Peripheral neurological complications during COVID-19: A single center experience

Background and aims

We highlight the peripheral neurologic complications of coronavirus disease 2019 (COVID-19) associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an ongoing global health emergency.

Methods

We evaluated twenty-five patients admitted to the COVID-19 Recovery Unit (CRU) at New York-Presbyterian Weill Cornell University Medical Center after intensive care hospitalization with confirmed severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), whom neurology was consulted for weakness and/or paresthesias. All patients were clinically evaluated by a neuromuscular neurologist who performed electrodiagnostic (EDX) studies when indicated. Magnetic resonance imaging (MRI) of the affected regions, along with nerve and muscle biopsies were obtained in select patients to better elucidate the underlying diagnosis.

Results

We found fourteen out of twenty-five patients with prolonged hospitalization for COVID-19 infection to have peripheral neurological complications, identified as plexopathies, peripheral neuropathies and entrapment neuropathies. The other eleven patients were not found to have peripheral neurologic causes for their symptoms. Patients with peripheral neurological complications often exhibited more than one type of concurrently. Specifically, there were four cases of plexopathies, nine cases of entrapment neuropathies, and six cases of peripheral neuropathies, which included cranial neuropathy, sciatic neuropathy, and multiple mononeuropathies.

Conclusions

We explore the possibility that the idiopathic peripheral neurologic complications could be manifestations of the COVID-19 disease spectrum, possibly resulting from micro-thrombotic induced nerve ischemia.

Isolated Anterior Interosseous Neuropathy Affecting Only the Flexor Digitorum Profundus to the Index Finger After Shoulder Arthroscopy: A Case Report and Review of the Literature

ABSTRACT

Anterior interosseous nerve neuropathy is an uncommon neuropathy with multiple potential etiologies. We present a rare case of anterior interosseous nerve neuropathy affecting only the flexor digitorum profundus to the index finger and occurring after shoulder arthroscopy. This unique presentation used a combination of both electrodiagnostic testing and neuromuscular ultrasound to obtain an accurate diagnosis and highlights the importance of these complementary tests in the evaluation of nerve disorders. To our knowledge, anterior interosseous nerve neuropathy after shoulder arthroscopy affecting only the flexor digitorum profundus to the index finger has not been previously described in the literature.

Anterior Interosseous Nerve Syndrome Reconsidered: A Critical Analysis Review

Anterior interosseous nerve syndrome (AINS) represents a form of neuralgic amyotrophy (Parsonage-Turner syndrome). AINS does not originate from external compression of the AIN in the forearm. Fascicular constrictions (FCs) of the median nerve are identified within the anterior interosseous fascicular group at or above the medial epicondyle. Spontaneous recovery is not ensured, leaving up to 30% of patients with permanent weakness or palsy. Fascicular microneurolysis of the median nerve, performed at or above the elbow, is a treatment option for patients who do not recover spontaneously.

Outcomes of Microneurolysis of Hourglass Constrictions in Chronic Neuralgic Amyotrophy

PURPOSE

Wide variability in the recovery of patients affected by neuralgic amyotrophy (NA) is recognized, with up to 30% experiencing residual motor deficits. Using magnetic resonance imaging and ultrasound (US), we identified hourglass constrictions (HGCs) in all affected nerves of patients with chronic motor paralysis from NA. We hypothesized that chronic NA patients undergoing microsurgical epineurolysis and perineurolysis of constrictions would experience greater recovery compared with patients managed nonsurgically.

METHODS

We treated 24 patients with chronic motor palsy from NA and HGCs identified on magnetic resonance imaging and US either with microsurgical epineurolysis and perineurolysis of HGCs (11 of 24) or nonsurgically (13 of 24). Muscle strength (both groups) and electrodiagnostic testing (EDX) (operative group) was performed before and after surgery. Preoperative EDX confirmed muscle denervation in the distribution of affected nerve(s). All patients met criteria for microneurolysis: 12 months without improvement since onset or failure of clinical and EDX improvement after 6 months documented by 3 successive examinations, each at least 6 weeks apart.

RESULTS

Mean time from onset to surgery was 12.5 ± 4.0 months. Average time to most recent post-onset follow-up occurred at 27.3 months (range, 18-42 months; 15 nerves). Average time to latest follow-up among nonsurgical patients was 33.6 months (range, 18-108 months; 16 nerves). Constrictions involved individual fascicular groups (FCs) of the median nerve and the suprascapular, axillary and radial nerves proper (HGCs). Nine of 11 operative patients experienced clinical recovery compared with 3 of 13 nonsurgical patients. EMG revealed significant motor unit recovery from axonal regeneration in the operative group.

CONCLUSIONS

Microsurgical epineurolysis and perineurolysis of FCs and HGCs was associated with significantly improved clinical and nerve regeneration at an average follow-up of 14.8 months compared with nonsurgical management. We recommend microneurolysis of HGCs and FCs as a treatment option for patients with chronic NA who have failed to improve with nonsurgical treatment.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Spontaneous Radial Nerve Palsy due to an Unrecognized Myofibroma: A Case Report

CASE

A 33-year-old woman presented with a six-month history of spontaneous radial nerve palsy and no identified lesion on imaging. She underwent operative exploration where an hourglass deformity was seen and resected. Pathology returned as a rare tumor, a myofibroma. The patient regained full radial nerve function.

CONCLUSIONS

A trial of observation is often indicated in the cases of isolated nerve palsy where anatomic lesions have been eliminated. This case highlights that imaging studies can miss a tumor involving nerve and that painless, spontaneous nerve palsy may be a time where early surgical intervention offers a better chance of recovery.

Bilateral idiopathic neuralgic amyotrophy involving selective branches of peripheral nerves with a stepwise progression: A case report

RATIONALE

This is a report about a rare case of idiopathic neuralgic amyotrophy (INA) involving selective peripheral nerve branches of bilateral upper extremities, which exhibited a stepwise progression.

PATIENT CONCERN

A 66-year-old woman presented with paresis of selective branches of bilateral median nerves, followed by paresis of bilateral posterior interosseous nerve (PIN) 8 weeks later.

DIAGNOSES

We diagnosed it as INA involving the selective motor branches of bilateral median nerves and bilateral PINs. Forearm magnetic resonance imaging combined with electrodiagnostic testing helped accurately identify the affected regions, and ultrasonography demonstrated a severe constriction of the left PIN.

INTERVENTIONS

Intravenous methylprednisolone partially relieved the pain and paralysis. Surgical neurolysis of the constricted left PIN was done for persistent paralysis.

OUTCOMES

The muscle power of the bilateral median nerve territories was recovered to nearly normal, but the muscle power of the left PIN territories remained at grade 1.

LESSONS

This case indicates that INA can manifest as a multiple mononeuropathy involving individual fascicular levels of peripheral nerve branches with focal constriction, and electrodiagnostic study combined with forearm MRI and ultrasonography can help in identifying affected lesion and predicting the prognosis.

Isolated spontaneous posterior interosseous nerve palsy: a review of aetiology and management

Isolated posterior interosseous nerve palsy is an uncommon condition and its management is controversial. Existing literature is sparse and a treatment algorithm based on existing best evidence is absent. A comprehensive review was undertaken to elucidate the causes of spontaneous posterior interosseous nerve palsy and suggest a management strategy based on the current evidence. Posterior interosseous nerve palsy can be broadly categorized as compressive and non-compressive, and the existing evidence supports surgical intervention for compressive palsy. For posterior interosseous nerve pathology with no compressive lesion on imaging, conservative management should be tried first. Surgery is therefore reserved for compressive lesions and for failure of conservative management. The commonly performed operative procedures include decompression and neurolysis, neurorrhaphy and nerve grafting, and tendon transfers with or without nerve grafting performed as a salvage procedure. The prognosis is poorer in patients aged > 50 years, those with a delay to surgery, and those who have had long-standing compression with severe fascicular thinning.

Magnetic resonance imaging patterns of mononeuropathic denervation in muscles with dual innervation

Magnetic resonance imaging (MRI) of mononeuropathy in muscles with dual innervation depicts geographic denervation corresponding to the affected nerve. Knowledge of the normal distribution of a muscle's neural supply is clinically relevant as partial muscle denervation represents a potential imaging pitfall that can be confused with other pathology, such as muscle strain. This article reviews the normal innervation pattern of extremity muscles with dual supply, providing illustrative examples of mononeuropathy affecting such muscles.

Ultrasonography in neuralgic amyotrophy: Sensitivity, spectrum of findings, and clinical correlations

INTRODUCTION

The aim of this study was to assess the value of ultrasonography in neuralgic amyotrophy.

METHODS

Fifty-three patients with 70 affected nerves were examined with high-resolution ultrasound.

RESULTS

The most commonly affected nerve was the anterior interosseous (23%). Ultrasonographic abnormalities in the affected nerves, rather than in the brachial plexus, were observed, with an overall sensitivity of 74%. Findings included the swelling of the nerve/fascicle with or without incomplete/complete constriction and rotational phenomena (nerve torsion and fascicular entwinement). A significant difference was found among the categories of ultrasonographic findings with respect to clinical outcome (P = 0.01). In nerves with complete constriction and rotational phenomena, reinnervation was absent or negligible, indicating surgery was warranted.

DISCUSSION

Ultrasonography may be used as a diagnostic aid in neuralgic amyotrophy, which was hitherto a clinical and electrophysiological diagnosis, and may also help in identifying potential surgical candidates. Muscle Nerve 56: 1054-1062, 2017.

Anterior Interosseous Nerve Neuropraxia Secondary to Shoulder Arthroscopy and Open Subpectoral Long Head Biceps Tenodesis

Arthroscopic rotator cuff tendon repair is a common elective procedure performed by trained orthopaedic surgeons with a relatively low complication rate. Specifically, isolated neuropraxia of the anterior interosseous nerve (AIN) is a very rare complication of shoulder arthroscopy. An analysis of peer-reviewed published literature revealed only three articles reporting a total of seven cases that describe this specific complication following standard shoulder arthroscopic procedures. This article reports on three patients diagnosed with AIN neuropraxia following routine shoulder arthroscopy done by a single surgeon within a three-year period. All three patients also underwent open biceps tenodesis immediately following completion of the arthroscopic procedures. The exact causal mechanism of AIN neuropraxia following shoulder arthroscopy with biceps tenodesis is not known. This case report reviews possible mechanisms with emphasis on specific factors that make a traction injury the most likely etiology in these cases. We critically analyze our operating room setup and patient positioning practices in light of the existing biomechanical and cadaveric research to propose changes to our standard practices that may help to reduce the incidence of this specific postoperative complication in patients undergoing elective shoulder arthroscopy with biceps tenodesis.