Neurosurgery of the peripheral nervous system: entrapment syndromes of the lower extremity

Persistent Symptoms of Ganglion Cysts in the Dorsal Foot

Background

A ganglion is a common benign cystic lesion, containing gelatinous material. Ganglia are most commonly asymptomatic, except for a lump, but symptoms depend on the location. A dorsal foot ganglion is typically painful. On the dorsal foot, the dorsalis pedis artery and the medial branch of the deep peroneal nerve are located under the fascia.

Objective

Five female patients of average age 45.8 ± 20 years (range, 12 to 60 years) with a painful ganglion in the dorsal foot were analyzed.

Results

Average lesion size was 2.94 ± 1.1 cm (range, 1.5 to 4.0 cm) and patients had experienced pain for a median of 2-3 years (range, 6 months to 3 years). Four patients had a single cystic lesion and 1 patient had developed multiple cystic lesions over the time that were associated with hypoesthesia. In 3 cases, symptomatic lesions were located deep beneath the fascia and were resected. In 2 cases, the depth of the non-resected lesions was shallow.

Conclusion

The cause of a painful dorsal foot ganglion can be attributed to its location in the thin subcutaneous tissue over the foot bone, in addition to its proximity to a nearby artery and nerve. Mild symptoms caused by a dorsal foot ganglion seem to be persistent, and the deeper the location, the more likely is the need for resection. To avoid nerve injury, anatomical knowledge is prerequisite to any puncturing procedure or operation performed.

What's new in the diagnosis and treatment of peripheral nerve entrapment neuropathies

Entrapment neuropathies can be common conditions with the potential to cause significant disability. Correct diagnosis is essential for proper management. This article is a review of recent developments related to diagnosis and treatment of various common and uncommon nerve entrapment disorders. When combined with classical peripheral nerve examination techniques, innovations in imaging modalities have led to more reliable diagnoses. Moreover, innovations in conservative and surgical techniques have been controversial as to their effects on patient outcome, but randomized controlled trials have provided important information regarding common operative techniques. Treatment strategies for painful peripheral neuropathies are also reviewed.

[The main tunnel syndromes]

Several tunnel syndromes are responsible for substantial functional impairment. The diagnosis has to be made and treatment is most often very simple--nerve decompression--with excellent results. Of these syndromes, the most common are median and ulnar tunnel syndromes of the wrist and ulnar tunnel syndrome of the elbow, but other syndromes must be identified at the risk of therapy failure due to poorly adapted treatment. Finally, good knowledge of this pathology must lead to prevention of the iatrogenic forms (sequelae of inguinal hernia treatment, ileac crest graft harvesting) by educating all surgeons interested in peripheral nerve surgery.

Anatomic site for proximal tibial nerve compression: a cadaver study

Primary compression of the tibial nerve beneath the fibromuscular sling of the origin of the soleus muscle is rarely discussed in the literature. To evaluate the location and characteristics of the soleal fibromuscular sling and its relationship to the tibial nerve, 36 cadaver limbs were dissected. The leg length, location of soleal fibromuscular sling, presence of a thickened fibrous band at the soleal sling, and narrowing in the tibial nerve were recorded. The average leg length was 47.8 cm (SD +/- 4.16). The fibromuscular soleal sling was 9.3 cm (SD +/- 1.44) distal to the medial tibial plateau. Although 56% (20/36) of specimens had a fibrous band, only 8% (3/36) demonstrated a focal narrowing directly under this fascial sling. This study demonstrates that the fibromuscular sling of the soleus muscle may act as a potential compression site of the tibial nerve. These findings offer insight and potential hope for those patients who have persistent plantar numbness after tarsal tunnel decompression and for those patients with plantar numbness who also have weakness of toe flexion.

Common Peroneal Nerve Palsy: An Unexpected Complication of Liver Surgery

BACKGROUND

Common peroneal nerve palsy is a well-recognized complication following surgery in lithotomy position, particularly colorectal and gynecologic surgery. But it is quite rare after liver surgery because patients are usually placed in supine position.

CASE REPORT

There were three cases of common peroneal nerve palsy after liver surgery in the past 2 years, including two cases of liver transplantation and one case of extended right hepatectomy. Two cases were bilateral and one case was unilateral. They were placed in supine position and the mean operative time was 8 hours. Patients complained symptom of foot drop within 1 week after operation. Electromyographic examinations showed evidence compatible with common peroneal nerve palsy. All of them improved with conservative treatment within 6 months.

CONCLUSION

Common peroneal nerve palsy may develop after liver surgery even in supine position. Injury to common peroneal nerve should be a concern before and during the operation. This complication could be managed conservatively with an uneventful result.

Compression neuropathies of the lower extremity

Compression neuropathies of the lower extremity can be just as disabling as compression neuropathies in the upper extremity. The most common compression neuropathies encountered in the lower extremity affect the lateral femoral cutaneous nerve, the peroneal nerve, the saphenous nerve, the sural nerve, and the tibial nerve (including their branches). These are discussed in terms of anatomy, etiologies, manifestations, and surgical treatment.

Nerve entrapments of the lower leg, ankle and foot in sport

Exercise-related leg pain is a common and yet difficult management problem in sports medicine. There are many common causes of such symptoms including stress fractures and muscle compartment syndromes. There are also a number of less common but important conditions including popliteal artery entrapment and nerve entrapment syndromes. Even for an astute clinician, distinction between the different medical causes may be difficult given that many of their presenting features overlap. This review highlights the common clinical presentations and raises a regional approach to the diagnosis of the neurogenic symptoms. In part, this overlapping presentation of different pathological conditions may be due to a common aetiological basis of many of these conditions namely, fascial dysfunction. The same fascial restriction that predisposes to muscle compartment syndromes may also envelop the neurovascular structures within the leg resulting in either ischaemic or neurogenic symptoms. For many athletes with chronic exercise-related leg pain, combinations of such problems often coexist suggesting a more widespread fascial pathology. In our clinical experience, we often label such patients as 'fasciopaths'; however, the precise pathophysiological basis of this fascial problem remains to be elucidated. This review discusses the various nerve entrapment syndromes in the lower limb that may result in exercise-related leg pain in the sporting context. The anatomy, clinical presentation, investigation, medical management and surgical treatment are discussed at length for each of the syndromes. It is clear from clinical experience that the outcome of surgical management of such syndromes fares much better where a clear dermatomal pain distribution is present or where focal weakness and/or sensory symptoms appropriate for the nerve are present. In many situations, however, nonspecific leg pain or vague nonlocalising sensory symptoms are present and in such situations, alternative diagnoses must be considered and investigated appropriately. As mentioned above, many different pathologies may coexist in the lower limb and may be a source of confusion for the clinician or alternatively may be the reason for poor treatment outcomes.