Isolated sural neuropathy presenting as lateral ankle pain

Ultrasound assessment of the sural nerve in patients with neuropathic pain after ankle surgery

INTRODUCTION

The sural nerve may be damaged after ankle injury. The aim of our study was to determine the diagnostic utility of high-resolution sonography in patients with ankle fractures treated by open reduction and internal fixation in whom there was a clinical suspicion of sural neuropathy.

METHODS

We examined the ultrasound (US) characteristics of patients with and without postsurgical sural neuropathic pain and healthy volunteers. Cross-sectional area (CSA), echogenicity, and vascularization of the sural nerves were recorded.

RESULTS

Fourteen participants and all sural nerves were identified. CSA (P < 0.001) and vascularization (P = 0.002) were increased in symptomatic patients when compared with asymptomatic patients and healthy volunteers. There were no significant differences in nerve echogenicity (P = 0.983).

DISCUSSION

US may be a valuable tool for evaluating clinically suspected sural nerve damage after ankle stabilization surgery. Sural nerve abnormalities are seen in patients with postsurgical neuropathic pain. Muscle Nerve 57: 407-413, 2018.

Diagnosis and management of the painful ankle/foot part 1: clinical anatomy and pathomechanics

Distinctive anatomical features can be witnessed in the ankle/foot complex, affording specific pathological conditions. Disorders of the ankle/foot complex are multifactoral and features in both the clinical anatomy and biomechanics contribute to the development of ankle/foot pain. The superior tibiofibular, distal tibiofibular, talocrural, subtalar, and midtarsal joint systems must all participate in function of the ankle/foot complex, as each biomechanically contributes to functional movements and clinical disorders witnessed in the lower extremity. A clinician's ability to effectively evaluate, diagnose, and treat the distal lower extremity is largely reliant upon a foundational understanding of the clinical anatomy and biomechanics of this complex complex. Thus, clinicians are encouraged to consider these distinctions when examining and diagnosing disorders of the ankle/foot.

Neuropathies of the foot

Compared with the common neuropathies affecting the hands (carpal tunnel syndrome and ulnar neuropathy), neuropathies of the feet have received less attention in the past. This is partly because of the rarity of these disorders as well as the lack of reliable electrophysiological tests for them. Over the years, nerve conduction tests for various nerves of the feet have been reported, and at this time techniques for all the nerves of the feet are available to the electromyographer. This review will provide up-to-date information on the current status of the research and issues relating to the neuropathies of the foot, with an emphasis on the most useful tests and the caveats for clinical neurophysiologists.

Sural neuropathy: Etiologies and predisposing factors

Isolated sural neuropathy is an uncommon diagnosis. We identified 36 patients with isolated sural neuropathy. Sixteen had various forms of ankle trauma, in three of whom the associated sural neuropathies developed following medical intervention. Three patients developed sural neuropathy associated with vasculitis, and there were single patients with schwannoma and ganglionic cyst. In patients without a history of trauma, structural causes, such as schwannoma or ganglionic cysts and vasculitis, should be considered and managed as appropriate.

The anatomic features of the sural nerve with an emphasis on its clinical importance

BACKGROUND

The sural nerve is formed by the union of the medial and lateral cutaneous nerves of the leg that originate from the tibial and common peroneal nerves. Operative procedures and traumatic injuries to the popliteal fossa, leg, ankle and foot place the sural nerve and its branches at risk. The aim of this study was to describe the course, variations and some clinically significant relations of the sural nerve.

METHODS

The sural nerve was dissected in 30 lower limbs (leg-ankle-foot) of 15 cadavers. The specimens were measured, drawn and photographed.

RESULTS

In 18 specimens (60%) the sural nerve originated from the union of the medial and lateral cutaneous nerves of the leg in the upper two-thirds of the leg (classic type). The union of the medial and lateral cutaneous branches was in the distal third of the leg in three specimens (10%). The lateral cutaneous nerve was absent in five (16.7%), and the medial cutaneous nerve was absent in 2 (6.7%) specimens. In two specimens (6.7%) the nerves had separate courses. The mean distance between the most prominent part of the lateral malleolus and the sural nerve was 12.76 +/- 8.79 mm. The mean distance between the tip of the lateral malleolus and sural nerve was 13.15 +/- 6.88 mm. The most common distribution of the sural nerve in the foot was to the lateral side of the fifth toe (60%), followed by the lateral two and a half toes (26.7%).

CONCLUSIONS

These described variations and measurements should be helpful for planning operative approaches that minimize the risk of sural nerve injury.

Occupational and Sport Related Traumatic Neuropathy

BACKGROUND

Sport and occupation related traumatic nerve injury is a common problem in the United States. While the physical requirements of each pursuit place participants at risk for injury to certain peripheral nervous system structures, the vast numbers of professional and recreational pursuits limits the ability to become familiar with nerve injuries specific to each. A more pragmatic approach is to apply knowledge of mechanisms of injury, physiology of nerve injury, regional anatomy, and at-risk peripheral nervous system structures to the routine neurologic history and physical assessment to arrive at a localizing and etiologic diagnosis.

REVIEW SUMMARY

The authors discuss potential mechanisms of nerve injury, the role of electrodiagnostic testing, regional peripheral nervous system anatomic considerations and lesion localization.

CONCLUSIONS

Despite the wide variety of professionally and recreationally induced peripheral nerve injuries, application of anatomic, physiologic and mechanistic considerations allow the neurologist to make an etiologic and localizing diagnosis.

Diagnosis and Management of the Painful Ankle/Foot. Part 2: Examination, Interpretation, and Management

Diagnosis, interpretation, and subsequent management of ankle/foot pathology can be challenging to clinicians. A sensitive and specific physical examination is the strategy of choice for diagnosing selected ankle/foot injuries and additional diagnostic procedures, at considerable cost, may not provide additional information for clinical diagnosis and management. Because of a distal location in the sclerotome and the reduced convergence of afferent signals from this region to the dorsal horn of the spinal cord, pain reference patterns are low and the localization of symptoms is trustworthy. Effective management of the painful ankle/foot is closely linked to a tissue-specific clinical examination. The examination of the ankle/foot should include passive and resistive tests that provide information regarding movement limitations and pain provocation. Special tests can augment the findings from the examination, suggesting compromises in the structural and functional integrity of the ankle/foot complex. The weight bearing function of the ankle/foot compounds the clinician's diagnostic picture, as limits and pain provocation are frequently produced only when the patient attempts to function in weight bearing. As a consequence, clinicians should consider this feature by implementing numerous weightbearing components in the diagnosis and management of ankle/foot afflictions. Limits in passive motion can be classified as either capsular or non-capsular patterns. Conversely, patients can present with ankle/foot pain that demonstrates no limitation of motion. Bursitis, tendopathy, compression neuropathy, and instability can produce ankle/foot pain that is challenging to diagnose, especially when they are the consequence of functional weight bearing. Numerous non-surgical measures can be implemented in treating the painful ankle/foot, reserving surgical interventions for those patients who are resistant to conservative care.