Ganglionic cyst of the deep peroneal nerve: description of a case

Deep peroneal nerve palsy due to osteochondroma arising from fibular head and proximal lateral tibia

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Osteochondroma are the most common benign tumors.

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Disease affecting knee joint in 94% of all cases.

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Clinicians should be aware of the possible tumoral lesions in drop foot etiology.

Following median and ulnar nerves, peroneal nerve entrapment is the most frequent nerve involvement in the body Katirji and Wilbourn (1998) [1].

Osteochondromas are the most common benign bone tumors comprising 9% of all bone tumors and 35% of benign bone tumors Porter (2000) [2].

Hereditary exostoses (HME) is an autosomal dominant disorder with variable penetrance characterized by multiple osteochondromas near joints. It is one of the most commonskeletal dysplasias with a frequency of about 1.18%.

In this study, we aimed to present a case with a drop foot resulting from osteochondromas of proximal tibia and fibula and help to guide the clinicians in differential diagnosis according to SCARE criteria Agha (2016) [3].

A rare cause of deep peroneal nerve palsy due to compression of synovial cyst - Case report

INTRODUCTION

Synovial cyst is a rare cause of compression neuropathy and its differential diagnosis can be misleading.

PRESENTATION OF CASE

This article presents clinical, radiological, and histological findings of deep peroneal nerve palsy due to compression of a synovial cyst in a 30-year-old patient admitted with sudden drop foot.

DISCUSSION

Focal nerve entrapment in lower extremity due to synovial cystis a rare entity. Differential diagnosis is important. Surgical excision is the main treatment method with high success rate.

CONCLUSION

Synovial cyst compression which can be treated easily with surgical excision should be considered in rapidly progressed drop foot.

Patterns of intraneural ganglion cyst descent

On the basis of the principles of the unifying articular theory, predictable patterns of proximal ascent have been described for fibular (peroneal) and tibial intraneural ganglion cysts in the knee region. The mechanism underlying distal descent into the terminal branches of the fibular and tibial nerves has not been previously elucidated. The purpose of this study was to demonstrate if and when cyst descent distal to the articular branch-joint connection occurs in intraneural ganglion cysts to understand directionality of intraneural cyst propagation. In Part I, the clinical records and MRIs of 20 consecutive patients treated at our institution for intraneural ganglion cysts (18 fibular and two tibial) arising from the superior tibiofibular joint were retrospectively analyzed. These patients underwent cyst decompression and disconnection of the articular branch. Five of these patients developed symptomatic cyst recurrence after cyst decompression without articular branch disconnection which was done elsewhere prior to our intervention. In Part II, five additional patients with intraneural ganglion cysts (three fibular and two tibial) treated at other institutions without disconnection of the articular branch were compared. These patients in Parts I and II demonstrated ascent of intraneural cyst to differing degrees (12 had evidence of sciatic nerve cross-over). In addition, all of these patients demonstrated previously unrecognized MRI evidence of intraneural cyst extending distally below the level of the articular branch to the joint of origin: cyst within the proximal most portions of the deep fibular and superficial fibular branches in fibular intraneural ganglion cysts and descending tibial branches in tibial intraneural ganglion cysts. The patients in Part I had complete resolution of their cysts at follow-up MRI examination 1 year postoperatively. The patients in Part II had intraneural recurrences postoperatively within the articular branch, the parent nerve, and the terminal branches, although in three cases they were subclinical. The authors demonstrate that cyst descent distal to the take-off of the articular branch to the joint of origin occurs regularly in patients with fibular and tibial intraneural ganglion cysts. The authors believe that parent terminal branch descent follows ascent up the articular branch from an affected joint of origin. This mechanism for bidirectional flow explains cyst within terminal branches of the fibular and tibial nerves and is dependent on pressure fluxes and resistances. This new pattern is consistent with principles previously described in a unified (articular) theory, is generalizable to other intraneural ganglion cysts arising from joints, and has important implications for pathogenesis and treatment of these intraneural cysts.

Acute onset of deep peroneal neuropathy during a golf game resulting from a ganglion cyst

We report a case of sudden onset of deep peroneal neuropathy resulting from a ganglion cyst. Electrophysiology demonstrated a severe deep peroneal neuropathy with axonal loss and probably proximal conduction block. Magnetic resonance imaging demonstrated a mass arising from the proximal tibiofibular joint extending along the peroneal nerve. Surgical resection of the ganglion resulted in gradual improvement of strength. Peroneal nerve ganglia should be considered in the evaluation of patients with sudden painless foot drop.

Peroneal intraneural ganglia: the importance of the articular branch. A unifying theory

OBJECT

Based on a large multicenter experience and a review of the literature, the authors propose a unifying theory to explain an articular origin of peroneal intraneural ganglia. They believe that this unifying theory explains certain intriguing, but poorly understood findings in the literature, including the proximity of the cyst to the joint, the unusual preferential deep peroneal nerve (DPN) deficit, the absence of a pure superficial peroneal nerve (SPN) involvement, the finding of a pedicle in 40% of cases, and the high (10-20%) recurrence rate.

METHODS

The authors believe that peroneal intraneural lesions are derived from the superior tibiofibular joint and communicate from it via a one-way valve. Given access to the articular branch, the cyst typically dissects proximally by the path of least resistance within the epineurium and up the DPN and the DPN component of the common peroneal nerve (CPN) before compressing nearby SPN fascicles. The authors present objective evidence based on anatomical, clinical, imaging, operative, and histological data that support this unifying theory.

CONCLUSIONS

The predictable clinical presentation, electrical studies, imaging characteristics, operative observations, and histological findings regarding peroneal intraneural ganglia can be understood in terms of their origin from the superior tibiofibular joint, the anatomy of the articular branch, and the internal topography of the peroneal nerve that the cyst invades. Understanding the controversial pathogenesis of these cysts will enable surgeons to perform operations based on the pathoanatomy of the articular branch of the CPN and the superior tibiofibular joint, which will ultimately improve clinical results.