Peroneal nerve entrapment at the knee localized by short segment stimulation

Fibular (peroneal) neuropathy

Fibular neuropathy has variable presenting features depending on the site of the lesion. Anatomical features make it susceptible to injury from extrinsic factors, particularly the superficial location of the nerve at the head of the fibula. There are many mechanisms of compression or other traumatic injury of the fibular nerve, as well as entrapment and intrinsic nerve lesions. Intraneural ganglion cysts are increasingly recognized when the mechanism of neuropathy is not clear from the medical history. Electrodiagnostic testing can contribute to the localization as well as the characterization of the pathologic process affecting the nerve. When the mechanism of injury is unclear from the analysis of the presentation, imaging with MRI and ultrasound may identify nerve lesions that warrant surgical intervention. The differential diagnosis of foot drop includes fibular neuropathy and other neurologic conditions, which can be distinguished through clinical and electrodiagnostic assessment. Rehabilitation measures, including ankle splinting, are important to improve function and safety when foot drop is present. Fibular neuropathy is less frequently painful than many other nerve lesions, but when it is painful, neuropathic medication may be required. Failure to spontaneously recover or the detection of a mass lesion may require surgical management.

The role of electrodiagnosis in focal neuropathies

Electrodiagnostic (EDX) testing plays an important role in confirming a mononeuropathy, localizing the site of nerve injury, defining the pathophysiology, and assessing the severity and prognosis. The combination of nerve conduction studies (NCS) and needle electromyography findings provides the necessary information to fully assess a nerve. The pattern of NCS abnormalities reflects the underlying pathophysiology, with focal slowing or conduction block in neuropraxic injuries and reduced amplitudes in axonotmetic injuries. Needle electromyography findings, including spontaneous activity and voluntary motor unit potential changes, complement the NCS findings and further characterize chronicity and degree of axon loss and reinnervation. EDX is used as an objective marker to follow the progression of a mononeuropathy over time.

Electrodiagnosis of Common Mononeuropathies: Median, Ulnar, and Fibular (Peroneal) Neuropathies

This article addresses common mononeuropathies seen in the electrodiagnostic laboratory. The most common mononeuropathies-median neuropathy at the wrist (carpal tunnel syndrome), ulnar neuropathy at the elbow, and fibular (peroneal) neuropathy at the fibular head-are reviewed. The causes, clinical presentations, approached to the electrodiagnostic studies (including nerve conduction studies and needle electromyography), and the typical findings are discussed.

Ulnar neuropathy at the elbow: Five new things

Ulnar neuropathy at the elbow (UNE) is the second most frequent compression neuropathy. While other diagnostic imaging tools are emerging to assist in the diagnosis of UNE, electrodiagnosis remains the gold standard. However, the electrodiagnostic approach to UNE presents unique challenges limiting its diagnostic accuracy. We review advances in 5 areas relevant to the diagnosis of UNE: technologic advancements with modern EMG machines have allowed for reconsideration of the question of experimental error and lesion detection; how temperature effects can lead to misdiagnosis; the effect of body mass index on the electrodiagnosis of UNE; the validation of short segment studies; and the emerging role of high-resolution sonography as a diagnostic tool.

Compression and entrapment neuropathies

Peripheral nerve entrapments are frequent. They usually appear in anatomical tunnels such as the carpal tunnel. Nerve compressions may be due to external pressure such as the fibular nerve at the fibular head. Malignant or benign tumors may also damage the nerve. For each nerve from the upper and lower limbs, detailed clinical, electrophysiological, imaging, and therapeutic aspects are described. In the upper limbs, carpal tunnel syndrome and ulnar neuropathy at the elbow are the most frequent manifestations; the radial nerve is less frequently involved. Other nerves may occasionally be damaged and these are described also. In the lower limbs, the fibular nerve is most frequently involved, usually at the fibular head by external compression. Other nerves may also be involved and are therefore described. The clinical and electrophysiological examination are very important for the diagnosis, but imaging is also of great use. Treatments available for each nerve disease are discussed.

Peroneal nerve dysfunction after total knee arthroplasty: characterization and treatment

The purpose of this study was to report on the presentation, evaluation, treatment, and outcome of patients who had a peroneal nerve dysfunction after total knee arthroplasty. Six patients were unable to achieve adequate range of motion after physical therapy, and the remaining 5 patients had sensory symptoms that interfered with daily activities despite adequate range of motion. All 11 patients had abnormal electrodiagnostic testing but had intact motor strength and were treated with surgical decompression of the nerve. The patients with motion problems had a mean increase in range of motion of 40 ° (range, 20 °-70 °) at final follow-up. All patients with dominant sensory symptoms had a resolution of leg and foot pain after treatment. Orthopedic surgeons should be aware of peroneal nerve dysfunction as a possible cause of unsatisfactory rehabilitation and/or persistent atypical lateral leg pain after total knee arthroplasty.

Peroneal nerve orthodromic sensory conduction technique: normative data

In some definite patients, a standard neurophysiological tool may not solve a complete differential diagnosis in common nerve peroneal neuropathy. In this study we have assessed a new simple procedure to study the orthodromic sensory conduction of both the superficial peroneal nerves (SPN) and deep peroneal nerves (DPN) in a heterogeneous group of 55 normal subjects. The mean sensory orthodromic conduction velocity of the SPN was 58.35 m/s. The mean sensory orthodromic conduction velocity of the mixed nerve action potential (MNAP) of the DPN was 55.27 m/s. The sensory conduction velocity, the amplitude of sensory-evoked potentials of SPN and DPN across the fibular head and the normative values are discussed. Our results confirm that these recording methods are easy to repeat and reliable in identifying peroneal neuropathy.

Compound nerve action potential of common peroneal nerve and sural nerve action potential in common peroneal neuropathy

To enhance the accuracy for determining the precise localization, the findings of the compound nerve action potentials (CNAPs) of the common peroneal nerve (CPN) were investigated in patients with common peroneal mononeuropathy (CPM) in the knee, and the sural sensory nerve action potentials (SNAPs) were also analyzed. Twenty-five patients with CPM in the knee were retrospectively reviewed. The findings of the CNAPs of the CPN recorded at the fibular neck and the sural SNAPs were analyzed. The lesion was localized at the fibular head (abnormal CNAPs) and at or distal to the fibular head (normal CNAPs). Seven patients were diagnosed as having a lesion at or distal to the fibular neck, and 18 cases were diagnosed as having a fibular head lesion. The sural SNAPs were normal in all the cases of lesion at or distal to the fibular neck. Among 18 cases of fibular head lesion, the sural SNAPs were normal in 7 patients: two cases of conduction block and 5 cases of mild axon loss. Eleven patients showed abnormal sural SNAPs. Of those, 9 cases were severe axon loss lesions and 2 patients were diagnosed as having severe axon loss with conduction block. The recording of the CNAPs may enhance precise localization of CPM in the knee. Moreover, the sural SNAPs could be affected by severe axonal lesion at the fibular head.

Practice parameter: utility of electrodiagnostic techniques in evaluating patients with suspected peroneal neuropathy: an evidence-based review

An evidence-based review of electrodiagnostic (EDX) techniques in the evaluation of peroneal neuropathy was conducted to determine whether these techniques are useful for diagnosis and prognostication in this disorder. A Medline search and a review of relevant sources were performed in 1999 and updated through July 2003 to identify articles describing the use of EDX in patients suspected to have peroneal neuropathy. From the 499 articles identified, 112 articles describing motor and sensory nerve conduction studies and needle electromyography in peroneal neuropathy were reviewed in detail; 11 articles met the predetermined literature inclusion criteria for the adequacy of EDX techniques employed. Six articles provided Class III evidence in support of a role for nerve conduction studies in making the diagnosis of peroneal neuropathy; five articles provided Class IV evidence. Implicit in making the diagnosis were normal EDX findings outside the distribution of the peroneal nerve. The current literature supports the use of EDX in patients with suspected peroneal neuropathy (Level C recommendation).

Compound nerve action potential of common peroneal nerve recorded at fibular neck: its clinical usefulness

OBJECTIVE

To determine the clinical usefulness of the compound nerve action potential of the common peroneal nerve recorded immediately distal to or at the fibular neck, at the same time stimulating the common peroneal nerve laterally at the posterior knee.

DESIGN

For recording the compound nerve action potential of the common peroneal nerve, the active recording electrode was secured just distal to or at the fibular neck area, whereas the stimulating electrode was placed on the medial border of the lateral hamstring tendon at the level of the popliteal crease. To reduce shock artifacts, a biphasic stimulation was used.

RESULTS

In 35 adults (n = 19 men), 70 nerves were tested. The compound nerve action potential from each individual was recorded. The compound nerve action potential amplitude of a baseline-to-negative peak and conduction velocity were measured on both sides. For comparisons of the side-to-side amplitude and conduction velocity, Wilcoxon's signed-rank test was applied.

CONCLUSION

This approach of recording the compound nerve action potential of the common peroneal nerve, in addition to conventional methods, may enhance the process of determining the precise localization of peroneal nerve lesion in the knee.