Fibular (Peroneal) Neuropathy

Evidence for small fiber neuropathy in early Parkinson's disease

INTRODUCTION

Parkinson's disease (PD) is neurodegenerative movement disorder affecting primarily the central nervous system with several recognized non-motor symptoms that can occur at various stages of the disease. Recently it has been shown that patients with PD may be prone to peripheral nervous system pathology in the form of a peripheral neuropathy (PN). It is unclear if PN is an inherent feature of PD or if it is an iatrogenic effect of the mainstay PD treatment Levodopa.

METHODS

To determine if peripheral neuropathy occurs in early untreated PD we employed a case-control study design using gold standard tests for PN, including neurological examination according to the Utah Early Neuropathy Scale (UENS) and nerve conduction studies, as well as new, more sensitive and informative tests for PN including the skin biopsy and corneal confocal microscopy (CCM).

RESULTS

We studied 26 patients with PD and 22 controls using the neurological examination and nerve conduction studies (NCS) and found no significant difference between groups except for some reduced vibration sense in the PD group. Epidermal nerve densities in the skin biopsies were similar between our cohorts. However, using CCM - a more sensitive test and a surrogate marker of small fiber damage in PN, we found that patients with PD had significantly reduced corneal nerve fiber densities and lengths as compared to controls.

CONCLUSIONS

We conclude that our positive CCM results provide evidence of preclinical PN in newly diagnosed PD patients.

Peroneal Nerve Palsy: Evaluation and Management

Peroneal nerve palsy is the most common entrapment neuropathy of the lower extremity. Numerous etiologies have been identified; however, compression remains the most common cause. Although injury to the nerve may occur anywhere along its course from the sciatic origin to the terminal branches in the foot and ankle, the most common site of compressive pathology is at the level of the fibular head. The most common presentation is acute complete or partial foot drop. Associated numbness in the foot or leg may be present, as well. Neurodiagnostic studies may be helpful for identifying the site of a lesion and determining the appropriate treatment and prognosis. Management varies based on the etiology or site of compression. Many patients benefit from nonsurgical measures, including activity modification, bracing, physical therapy, and medication. Surgical decompression should be considered for refractory cases and those with compressive masses, acute lacerations, or severe conduction changes. Results of surgical decompression are typically favorable. Tendon and nerve transfers can be used in the setting of failed decompression or for patients with a poor prognosis for nerve recovery.

A Unique Case of Common Peroneal Nerve Entrapment

The authors present a case of a previously healthy 36-year-old man with a 3-day history of spontaneous complete right lower extremity foot drop. He noticed the symptoms immediately when he attempted to stand after waking from sleep. The patient had no history of similar symptoms, recent trauma, or peripheral nerve disease. Physical examination showed a slap foot gait, complete numbness of the lateral leg and dorsal foot, and 0/5 strength with ankle and great toe dorsiflexion and ankle eversion. Serum laboratory studies showed normal values. Nerve conduction studies confirmed increased latency and decreased amplitude of the right peroneal nerve at the knee, whereas electromyography showed denervation of the tibialis anterior and extensor digitorum brevis. Anteroposterior and lateral radiographs showed a normal right knee with the exception of a posterior fibular neck exostosis. Physical therapy, an ankle-foot orthosis, and a 5-day course of oral prednisone burst (50 mg) were prescribed. After 1 month of therapy without resolution, the patient underwent surgical release of the common peroneal nerve and excision of the bony prominence. Twelve days postoperatively, the patient had no sensory improvements but had improved findings on motor examination. Three months postoperatively, the patient had near-normal sensation to light touch in the superficial and deep peroneal nerves, with 5/5 strength and a normal gait. The patient returned to all activity without limitations. The authors present this unique case describing a fibro-osseous source of common peroneal compressive neuropathy and review the literature for spontaneous peroneal entrapment, highlighting the importance of prompt diagnosis and treatment.

A rare cause of 'drop foot' in the pediatric age group: Proximal fibular osteochondroma a report of 5 cases

INTRODUCTION

The fibular nerve is the most frequent site of neural entrapment in the lower extremity and the third most common site in the body, following the median and ulnar nerves. The peroneal nerve is commonly injured upon trauma. Additionally, a dropped foot might be a symptom related to the central nervous system or spinal pathologies in pediatric patients. Entrapment of the peripheral nerve as an etiologic cause should be kept in mind and further analyzed in orthopedic surgery clinics.

PRESENTATION OF CASE

In this study, the evaluation and treatment results of five patients with no history of trauma, who underwent diagnostic procedures and treatment in various clinics (physical therapy and rehabilitation and neurosurgery), are reported. The patients underwent several treatments without diagnosis of the primary etiology. Upon initial consultation at our department, osteochondroma at the proximal fibula was detected after physical examination and radiologic assessment. During surgery, the peroneal nerve was dissected, starting from a level above the knee joint. Following nerve release, the osteochondroma was removed, including its cartilage cap. Consequently, recovery was observed in all five cases after surgery.

DISCUSSION

Many factors may cause non-traumatic neuropathies. However, due to their rare occurrence, lesions such as osteochondromas may be overlooked at non-orthopedic clinics. Nerve entrapment due to proximal fibular osteochondroma is rare. Surgical treatment planning plays a critical role in nerve entrapment cases.

CONCLUSION

Despite its frequent occurrence, a drop foot associated with peroneal nerve entrapment by an osteochondroma is not easily remembered and diagnosed. Especially in pediatric cases, inadequate clinical consultation and a lack of appropriate radiologic studies may result in a delay in diagnosing peroneal nerve lesions.