Outcome and Prognosis of Microsurgical Decompression in Idiopathic Severe Common Fibular Nerve Entrapment: Prospective Clinical Study

Feasibility of a promising pulsed electrostimulator for rapid motor recovery of foot drop

Purpose

Foot drop still occurs in clinical practice, including in our case. Treatments for foot drop vary based on its etiology and severity of symptoms. Hence, in intractable foot drop cases, an invasive surgical intervention is needed. Here, we introduce a special noninvasive technique to treat our patient's foot drop. In this approach, we applied STIMPOD NMS460 neuromuscular stimulator device (STIMPOD NMS460), which is a low-frequency (10 Hz or less) transcutaneous electrical nerve stimulation (TENS) device with a pulsed radiofrequency (PRF) component. We are eager to know how effective the device is in treating foot drop, and we compared it with two kinds of surgical interventions.

Materials and methods

The device settings are 5 Hz in frequency and 30mA in current amplitude. The device was applied on her left side at the L4 and L5 regions and at the fibular head. Each therapy session consists of individual 15-min treatments on these two body areas, and it only takes a total of 30 minutes. We recorded the change in ankle dorsiflexion degrees and muscle strength of our patient.

Results and Conclusions

To our surprise, our patient's actual treatment status through STIMPOD NMS460 showed more effective recovery and no specific side effects than surgical interventions in similar conditions. Besides, after a three-month intervention, her affected ankle dorsiflexion recovered to almost her usual status. The reason why this device has such an effect may be that it has the benefits of TENS and PRF. Besides, some studies have revealed the nerve-repair effect of TENS and PRF. In conclusion, we believe that this device is fairly promising and may be qualified to be used in other patients with foot drop.

Surgical Outcomes of Common Peroneal Nerve Entrapment Neuropathy Associated with L5 Radiculopathy

Impingement of the common peroneal nerve, a branch of the L5 nerve root, causes common peroneal nerve entrapment neuropathy (CPNE). Although there are cases of CPNE associated with L5 radiculopathy, surgical intervention's effectiveness remains to be elucidated. This retrospective case-control study aimed to evaluate the efficacy of surgery in patients with CPNE associated with L5 radiculopathy. Twenty-two patients (25 limbs) with surgically treated CPNE between 2015 and 2022 were retrospectively reviewed. The limbs were classified into two groups: group R (limbs of CPNE associated with L5 radiculopathy) and group O (limbs of CPNE without L5 radiculopathy). The durations from onset to surgery, the nerve conduction studies (NCSs), and postoperative improvement rates for motor weakness, pain, and dysesthesia were compared between the groups. Group R included 15 limbs (13 patients), and group O included 10 limbs (9 patients). There were no significant differences in the duration from onset to surgery or abnormal findings of NCS between the two groups. The postoperative improvement rates were 88% and 100% (p = 0.62) for muscle weakness, 87% and 80% (p = 0.53) for pain, and 71% and 56% (p = 0.37) for dysesthesia in group R and group O, respectively, without significant differences between groups. CPNE associated with L5 radiculopathy is common, and the results of the present study showed that the surgical outcomes in such cases were satisfactory and comparable to those in CPNE without L5 radiculopathy.

Conservative versus surgical treatment of foot drop in peroneal nerve entrapment: rationale and design of a prospective, multi-centre, randomized parallel-group controlled trial

BACKGROUND

High-quality evidence is lacking to support one treatment strategy over another in patients with foot drop due to peroneal nerve entrapment. This leads to strong variation in daily practice.

METHODS/DESIGN

The FOOTDROP (Follow-up and Outcome of Operative Treatment with Decompressive Release Of The Peroneal nerve) trial is a randomized, multi-centre study in which patients with peroneal nerve entrapment and persistent foot drop, despite initial conservative treatment, will be randomized 10 (± 4) weeks after onset between non-invasive treatment and surgical decompression. The primary endpoint is the difference in distance covered during the 6-min walk test between randomization and 9 months later. Time to recovery is the key secondary endpoint. Other secondary outcome measures encompass ankle dorsiflexion strength (MRC score and isometric dynamometry), gait assessment (10-m walk test, functional ambulation categories, Stanmore questionnaire), patient-reported outcome measures (EQ5D-5L), surgical complications, neurological deficits (sensory changes, motor scores for ankle eversion and hallux extension), health economic assessment (WPAI) and electrodiagnostic assessment.

DISCUSSION

The results of this randomized trial may elucidate the role of surgical decompression of the peroneal nerve and aid in clinical decision-making.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04695834. Registered on 4 January 2021.

An Update on Peroneal Nerve Entrapment and Neuropathy

Peroneal neuropathy is the most common compressive neuropathy of the lower extremity. It should be included in the differential diagnosis for patients presenting with foot drop, the pain of the lower extremity, or numbness of the lower extremity. Symptoms of peroneal neuropathy may occur due to compression of the common peroneal nerve (CPN), superficial peroneal nerve (SPN), or deep peroneal nerve (DPN), each with different clinical presentations. The CPN is most commonly compressed by the bony prominence of the fibula, the SPN most commonly entrapped as it exits the lateral compartment of the leg, and the DPN as it crosses underneath the extensor retinaculum. Accurate and timely diagnosis of any peroneal neuropathy is important to avoid progression of nerve injury and permanent nerve damage. The diagnosis is often made with physical exam findings of decreased strength, altered sensation, and gait abnormalities. Motor nerve conduction studies, electromyography studies, and diagnostic nerve blocks can also assist in diagnosis and prognosis. First-line treatments include removing anything that may be causing external compression, providing stability to unstable joints, and reducing inflammation. Although many peroneal nerve entrapments will resolve with observation and activity modification, surgical treatment is often required when entrapment is refractory to these conservative management strategies. Recently, additional options including microsurgical decompression and percutaneous peripheral nerve stimulation have been reported; however, large studies reporting outcomes are lacking.

Treatment approach to isolated common peroneal nerve palsy by mechanism of injury: Systematic review and meta-analysis of individual participants' data

BACKGROUND

We reviewed the individual participant data of patients who sustained isolated common peroneal nerve (CPN) injuries resulting in foot drop. Functional results were compared between eight interventions for CPN palsies to determine step-wise treatment approaches for the underlying mechanisms of nerve injury.

METHODS

PubMed, Embase, Cochrane Library, Web of Science, Scopus, and CINAHL databases were searched. PRISMA-IPD and Cochrane guidelines were followed in the data search. Eligible patients sustained isolated CPN injuries resulting in their foot drop. Patients were stratified by mechanisms of nerve injury, ages, duration of motor symptoms, and nerve defect/zone of injury sizes, and were compared by functional results (poor = 0, fair = 1, good = 2, excellent = 3), using meta-regression between interventions. Interventions evaluated were primary neurorrhaphy, neurolysis, nerve grafts, partial nerve transfer, neuromusculotendinous transfer, tendon transfer, ankle-foot orthosis (AFO), and arthrodesis.

RESULTS

One hundred and forty-four studies included 1284 patients published from 1985 through 2020. Transection/Cut: Excellent functional results following tendon transfer (OR: 126, 95%CI: 6.9, 2279.7, p=0.001), compared to AFO. Rupture/Avulsion: Excellent functional results following tendon transfer (OR: 73985359, 95%CI: 73985359, 73985359, p<0.001), nerve graft (OR: 4465917, 95%CI: 1288542, 15478276, p<0.001), and neuromusculotendinous transfer (OR: 42277348, 95%CI: 3001397, 595514030, p<0.001), compared to AFO. Traction/Stretch: Good functional results following tendon transfer (OR: 4.1, 95%CI: 1.17, 14.38, p=0.028), compared to AFO. Entrapment: Excellent functional results following neurolysis (OR: 4.6, 95%CI: 1.3, 16.6, p=0.019), compared to AFO.

CONCLUSIONS

Functional results may be optimized for treatments by the mechanism of nerve injury. Transection/Cut and Traction/Stretch had the best functional results following tendon transfer. Rupture/Avulsion had the best functional results following tendon transfer, nerve graft, or neuromusculotendinous transfer. Entrapment had the best functional results following neurolysis.

Evidence in peroneal nerve entrapment: A scoping review

BACKGROUND AND PURPOSE

Daily management of patients with foot drop due to peroneal nerve entrapment varies between a purely conservative treatment and early surgery, with no high-quality evidence to guide current practice. Electrodiagnostic (EDX) prognostic features and the value of imaging in establishing and supplementing the diagnosis have not been clearly established.

METHODS

We performed a literature search in the online databases MEDLINE, Embase, and the Cochrane Library. Of the 42 unique articles meeting the eligibility criteria, 10 discussed diagnostic performance of imaging, 11 reported EDX limits for abnormal values and/or the value of EDX in prognostication, and 26 focused on treatment outcome.

RESULTS

Studies report high sensitivity and specificity of both ultrasound (varying respectively from 47.1% to 91% and from 53% to 100%) and magnetic resonance imaging (MRI; varying respectively from 31% to 100% and from 73% to 100%). One comparative trial favoured ultrasound over MRI. Variable criteria for a conduction block (>20%-≥50) were reported. A motor conduction block and any baseline compound motor action potential response were identified as predictors of good outcome. Based predominantly on case series, the percentage of patients with good outcome ranged 0%-100% after conservative treatment and 40%-100% after neurolysis. No study compared both treatments.

CONCLUSIONS

Ultrasound and MRI have good accuracy, and introducing imaging in the standard diagnostic workup should be considered. Further research should focus on the role of EDX in prognostication. No recommendation on the optimal treatment strategy of peroneal nerve entrapment can be made, warranting future randomized controlled trials.

Clinical Outcomes After Neurolysis for the Treatment of Peroneal Nerve Palsy: A Systematic Review and Meta-Analysis

BACKGROUND

Neurolysis techniques have been adapted for decompression of peripheral nerves in multiple locations, including the common peroneal nerve (CPN) at the fibular neck. The aim of this study was to conduct a systematic review and meta-analysis to summarize the clinical outcomes of neurolysis for the management of peroneal nerve palsy (PNP).

METHODS

Preferred Reporting Systems for Systematic Reviews and Meta-Analyses guidelines were followed for this meta-analysis. Four databases were queried, and randomized clinical trials, cohort studies, case-control studies, and case series with n > 10 published in English that evaluated clinical outcomes of neurolysis for the treatment of PNP and foot drop were included. Two reviewers completed screening and data extraction. Methodological quality was evaluated using the Newcastle-Ottawa Scale.

RESULTS

A total of 493 articles were identified through literature search. Title and abstract screening identified 39 studies for full-text screening. Ten articles met the inclusion criteria for qualitative analysis, and 8 had complete data for meta-analysis.Overall, there were 368 patients (370 nerves) who had neurolysis of the CPN for PNP, of which 59.2% (n = 218) were men and 40.8% (n = 150) were women. The mean age of the patients was 47.1 years (SD, 10.0 years), mean time to surgery was 9.65 months (SD, 6.3 months), and mean follow-up time was 28 months (SD, 14.0 months). The median preoperative Medical Research Council (MRC) score was 1 (IQR 0, 3), with 42.2% (n = 156) having MRC score of 0. The median postoperative MRC score was 5 (IQR 4, 5), with 53.9% (n = 199) having MRC score of 5. Complications of neurolysis of the peroneal nerve for treatment of PNP included postoperative infection (0.54%, n = 2), wound dehiscence (0.27%, n = 1), hematoma (0.54%, n = 2), bleeding (0.27%, n = 1), relapse of PNP (0.27%, n = 1), and 1 case of mortality due to sepsis.

CONCLUSIONS

Our meta-analysis shows that neurolysis of the CPN is safe and improves ankle dorsiflexion strength in patients with PNP. Future studies should use a standardized method of measuring sensory outcomes, and studies of higher levels of evidence are needed to better assess the clinical outcomes of neurolysis for treatment of PNP.