Peroneal and tibial intraneural ganglia: correlation between intraepineurial compartments observed on magnetic resonance images and the potential importance of these compartments

A Rare Case of Tibial Intraneural Ganglion Cyst Arising From the Tibiofibular Joint

Intraneural ganglion cysts are a rare occurrence. They are most commonly found originating from the common peroneal nerve but are also frequently reported on the radial, ulnar, median, sciatic, tibial, and posterior interosseous nerves. A typical clinical presentation is posterior knee and calf pain resulting from tibial neuropathy with preferential degeneration of the popliteus muscle. Symptoms include pain, paresthesias, and decreased strength that originates in the knee and commonly extends to the plantar surface of the foot. These findings can be mistaken for lumbar neuropathies and compression of the sacral nerve roots. Differential diagnosis includes peripheral nerve sheath tumors, Baker’s cysts, extraneural ganglion cysts, and atypical vascular or lymphatic malformations. In this case report, the patient was a 61-year-old male, previously in good health, who presented with progressive pain in his medial left hamstring as well as weakness in left foot plantar flexion and paresthesias in the plantar aspect of his left foot. He first noticed impairments with his ability to push off with his left foot when running. His electromyogram (EMG) was abnormal and subsequent MRI of the left leg showed a complex intraneural ganglion cyst arising from the tibiofibular joint and ascending into the tibial nerve. He underwent indirect decompression through joint resection. Unfortunately, he did not have clinical improvement on one-year follow-up. Overall, symptomatic treatment of intraneural ganglion cyst includes decompression, surgical excision, or minimally invasive decompression by percutaneous aspiration of the ganglion under ultrasound guidance.

Clinical outcome after decompression of intraneural peroneal ganglion cyst and its morphologic correlation to postoperative nerve ultrasound

OBJECTIVE

Intraneural ganglion cysts are rare and benign mucinous lesions that affect peripheral nerves, most frequently the common peroneal nerve (CPN). The precise pathophysiological mechanisms of intraneural ganglion cyst development remain unclear. A well-established theory suggests the spread of mucinous fluid along the articular branch of the peroneal nerve as the underlying mechanism. Clinical outcome following decompression of intraneural ganglion cysts has been demonstrated to be excellent. The aim of this study was to evaluate the correlation between clinical outcome and ultrasound-detected morphological nerve features following decompression of intraneural ganglion cysts of the CPN.

METHODS

Data were retrospectively analyzed from 20 patients who underwent common peroneal nerve ganglion cyst decompression surgery at the Universität Ulm/Günzburg Neurosurgery Department between October 2003 and October 2017. Postoperative clinical outcome was evaluated by assessment of the muscular strength of the anterior tibial muscle, the extensor hallucis longus muscle, and the peroneus muscle according to the Medical Research Council grading system. Hypesthesia was measured by sensation testing. In all patients, postoperative morphological assessment of the peroneal nerve was conducted between October 2016 and October 2017 using the iU22 Philips Medical ultrasound system at the last routine follow-up appointment. Finally, the correlations between morphological changes in nerve ultrasound and postoperative clinical outcomes were evaluated.

RESULTS

During the postoperative ultrasound scan an intraneural hypoechogenic ring structure located at the medial side of the peroneal nerve was detected in 15 (75%) of 20 patients, 14 of whom demonstrated an improvement in motor function. A regular intraneural fasicular structure was identified in 3 patients (15%), who also reported recovery. In 1 patient, a recurrent cyst was detected, and 1 patient showed intraneural fibrosis for which recovery did not occur in the year following the procedure. Two patients (10%) developed neuropathic pain that could not be explained by nerve ultrasound findings.

CONCLUSIONS

The results of this study demonstrate significant recovery from preoperative weakness after decompression of intraneural ganglion cysts of the CPN. A favorable clinical outcome was highly correlated with an intraneural hypoechogenic ring-shaped structure on the medial side of the CPN identified during a follow-up postoperative ultrasound scan. These study results indicate the potential benefit of ultrasound scanning as a prognostic tool following decompression procedures for intraneural ganglion cysts of the CPN.

Long-Term Functional Outcome After Surgical Treatment of Peroneal Intraneural Ganglion Cyst

BACKGROUND

Intraneural ganglia are benign mucinous cystic formations that originate within the epineurium of peripheral nerves. Different treatments have been recommended, with an overall satisfactory outcome. In this paper, we aim to evaluate the long-term outcomes of surgical treatment of peroneal intraneural ganglia by reviewing our local institutional experience.

METHODS

We performed a case series review of peroneal intraneural ganglia surgical treatment performed by the senior author. Demographic and surgical details were abstracted from the medical record for each patient. Electrodiagnostic studies and magnetic resonance imaging (MRI) were performed in all patients pre- and postoperatively.

RESULTS

Eight men were enrolled, with an average age at time of surgery of 47.5 years (range 28-68 years). Motor testing revealed a preoperative deficit of dorsiflexion, eversion, and toe extension in 7 patients, with a median preoperative Medical Research Council (MRC) score of 0/5. Sensory loss in the distribution of the common peroneal nerve was present in 7 patients. Mean clinical follow-up time was 113 months (range 32-189 months). Significant pain relief was achieved in all patients. Overall neurologic function was improved, more so for motor function. The median postoperative dorsiflexion, eversion, and toe extension at last follow-up were MRC score of 5/5. No complications occurred postoperatively. There was no clinical evidence of intraneural recurrence, as confirmed in postoperative MRI. In 2 patients, an extraneural cystic formation was visible in the anterior muscular compartment.

CONCLUSIONS

The data from our series support excellent long-term postoperative motor outcomes with a low recurrence rate. To avoid extraneural recurrence, resection of the superior tibiofibular joint is necessary.

The nearly invisible intraneural cyst: a new and emerging part of the spectrum

OBJECTIVE

The authors have observed that a subset of patients referred for evaluation of peroneal neuropathy with “negative” findings on MRI of the knee have subtle evidence of a peroneal intraneural ganglion cyst on subsequent closer inspection. The objective of this study was to introduce the nearly invisible peroneal intraneural ganglion cyst and provide illustrative cases. The authors further wanted to identify clues to the presence of a nearly invisible cyst.

METHODS

Illustrative cases demonstrating nearly invisible peroneal intraneural ganglion cysts were retrospectively reviewed and are presented. Case history and physical examination, imaging, and intraoperative findings were reviewed for each case. The outcomes of interest were the size and configuration of peroneal intraneural ganglion cysts over time, relative to various interventions that were performed, and in relation to physical examination and electrodiagnostic findings.

RESULTS

The authors present a series of cases that highlight the dynamic nature of peroneal intraneural ganglion cysts and introduce the nearly invisible cyst as a new and emerging part of the spectrum. The cases demonstrate changes in size and morphology over time of both the intraneural and extraneural compartments of these cysts. Despite “negative” MR imaging findings, nearly invisible cysts can be identified in a subset of patients.

CONCLUSIONS

The authors demonstrate here that peroneal intraneural ganglion cysts ride a roller coaster of change in both size and morphology over time, and they describe the nearly invisible cyst as one end of the spectrum. They identified clues to the presence of a nearly invisible cyst, including deep peroneal predominant symptoms, fluctuating symptoms, denervation changes in the tibialis anterior muscle, and abnormalities of the superior tibiofibular joint, and they correlate the subtle imaging findings to the internal fascicular topography of the common peroneal nerve. The description of the nearly invisible cyst may allow for increased recognition of this pathological entity that occurs with a spectrum of findings.

Intraneural Ganglions of the Hand and Wrist

PURPOSE

To review 15 patients who were treated for intraneural ganglions of the hand and wrist.

METHODS

Between 1990 and 2012, 15 patients were treated for intraneural ganglions of the hand and wrist. There were 9 women and 6 men, averaged age 42 years. Ten patients presented with a mass and 5 with symptoms of entrapment neuropathy. The ganglions involved the ulnar nerve at the wrist in 5 patients, the dorsal branch of the ulnar nerve in 2, the superficial radial nerve in 2, a digital nerve in 4, and the dorsal branch of a digital nerve in 2. Eight patients had magnetic resonance imaging evaluations that showed cystic masses that did not confirm intraneural ganglions. In all patients diagnosis was made intraoperatively. Ganglions were treated by intraneural dissection and excision of the cyst in 10 patients, excision of the articular branch and decompression of the cyst in 4, and excision of the ganglion and the nerve in 1.

RESULTS

Postoperative follow-up averaged 57 months. There were no complications or recurrences. Five patients had transient paresthesias that improved after an average of 2 months. Preoperative symptoms improved in all patients. Patients returned to normal daily and work activities at an average of 10 days.

CONCLUSIONS

Intraneural ganglions should be considered in the differential diagnosis of a mass in the vicinity of a nerve. Surgical excision is usually curative but simple excision of the articular branch and decompression of the cyst seems simpler and equally effective.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

A ganglion within the ulnar nerve and communication with the distal radioulnar joint via an articular branch: case report

An intraneural ganglion is rare, and involvement of an articular nerve may suggest a possible pathogenesis. We report an intraneural ganglion of the ulnar nerve with a connection to the distal radioulnar joint via the articular branch. We excised the ganglion, the stalk, and the articular branch. To date, there has been no recurrence.

An ulnar intraneural ganglion arising from the pisotriquetral joint: case report

Intraneural ganglions of the hand are rare and remain poorly understood. We report a case of an intraneural ganglion arising from the pisotriquetral joint that penetrated the ulnar nerve at Guyon's canal. Although rare, these ganglions should be considered in the differential diagnosis of any neoplasms causing compression neuropathy.

THE UNIFYING ARTICULAR (SYNOVIAL) ORIGIN OF INTRANEURAL GANGLIA

THE PATHOGENESIS OF intraneural ganglia has been an issue of curiosity, controversy, and contention for 200 years. Three major theories have been proposed to explain their existence, namely, 1) degenerative, 2) synovial (articular), and 3) tumoral theories, each of which only partially explains the observations made by a number of investigators. As a result, differing operative strategies have been described; these generally meet with incomplete neurological recoveries and high rates of recurrence. Recent advances in magnetic resonance imaging and critical analysis of the literature have clarified the mechanisms underlying the formation and propagation of these cysts, thereby confirming the unifying articular (synovial) theory. By identifying the shared features of the typical cases and explaining atypical examples or clinical outliers, several fundamental principles have been described. These include: 1) a joint origin; 2) dissection of fluid from that joint along an articular nerve branch, extension occurring via a path of least resistance; and 3) cyst size, extent, and directionality being influenced by pressures and pressure fluxes. We believe that understanding the pathogenesis of these cysts will be reflected in optimal surgical approaches, improved outcomes, and decreased frequency, if not elimination, of recurrences. This article describes the ongoing process of critically analyzing and challenging previous observations and evidence in an effort to prove a concept and a theory.