Peroneal intraneural ganglia: the importance of the articular branch. Clinical series

Intraneural Ganglion Cysts Arising from the Hip Joint as Rare Causes of Sciatic Neuropathy: A Case Series of 13 Patients Treated with Hip Arthroscopy

BACKGROUND

Sciatic neuropathy can result from pressure, injury, or inflammation around the sciatic nerve. In rare instances, sciatic neuropathy is caused by an intraneural ganglion cyst (IGC) originating from the hip joint. However, an effective treatment modality for this condition has not yet been established. The purpose of the present study was to evaluate the clinical and radiographic outcomes of hip arthroscopy for the treatment of IGCs involving the sciatic nerve.

METHODS

We reviewed the records on a consecutive series of hip arthroscopy procedures that had been performed by a single surgeon for the treatment of sciatic IGCs between July 2016 and February 2022. Thirteen Asian patients (13 hips) with symptomatic sciatic neuropathy were included. During arthroscopic surgery, IGCs were decompressed by enlarging their periarticular connection. Magnetic resonance imaging (MRI) and electrodiagnostic evaluation were routinely performed. The visual analog scale (VAS) for pain and modified Harris hip score (mHHS) were used for clinical evaluations. The mean age at the time of surgery was 57 years (range, 23 to 72 years), and the mean duration of follow-up was 41 months (range, 24 to 87 months).

RESULTS

The mean VAS score decreased from 8.3 preoperatively to 1.9 at the latest evaluation (p < 0.001). Satisfactory pain relief was reported by 12 patients (92%), including 9 patients (69%) who had complete remission. Four of the 6 patients with sensory impairment and 3 of the 4 patients with motor weakness reported complete recovery. The mean mHHS improved from 51.5 to 94.1 (p < 0.001). In MRI comparisons, the mean largest diameter and length of IGCs decreased from 2.6 to 0.5 cm (p < 0.001) and from 6.8 to 0.6 cm (p < 0.001), respectively. IGCs completely disappeared on MRI in 9 patients (69%). The latest electrodiagnostic studies confirmed improvement in all 12 patients with preoperative abnormalities. One patient (8%) with symptomatic recurrence was successfully treated with revision arthroscopic decompression.

CONCLUSIONS

In patients with sciatic neuropathy, the possibility of IGCs arising from the hip should be considered. Our findings suggest that arthroscopic hip surgery is a less-invasive and more-effective treatment for relieving neuropathic pain and neurological deficits associated with sciatic IGCs.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Complete foot drop due to atypical peroneal ganglion in a 13 ½ year old boy

INTRODUCTION

Peroneal nerve palsy due to compression by an intraneural ganglion is an uncommon entity in the pediatric setting with a need for surgical treatment. Uniquely in this case, the ganglion presented as an elongated instead of a typical round cyst, delaying diagnosis and treatment.

CASE PRESENTATION

We present the case of a 13 ½ year old boy with increasing peroneal nerve palsy due to an atypically shaped intraneural ganglion. An MRI of the knee revealed an elongated peroneal ganglion compressing the nerve between the lateral insertion of the gastrocnemius muscle and fibular head over a length of 10 cm. After surgical decompression and physiotherapy the peroneal nerve recovered well, achieving M 4-5 one year after surgery.

CONCLUSION

The atypical shape of the present peroneal ganglion delayed diagnosis and correct treatment. Though rare in the pediatric setting, this entity must be specifically looked for during the diagnostic workup of peroneal palsy, for time to surgery determines neurological outcome.

Cubital Tunnel Syndrome Due to Intraneural Ganglion Cysts of the Ulnar Nerve With Joint-Cyst Connection at the Elbow

BACKGROUND AND OBJECTIVES

The unifying articular theory suggests that intraneural ganglion cysts in the cubital tunnel arise from the elbow joint and are connected to the ulnar nerve through an articular branch. This study aimed to report our clinical experience with these cysts and our surgical findings and outcomes.

METHODS

We retrospectively analyzed 13 patients who underwent surgery for cubital tunnel syndrome caused by an intraneural ganglion cyst of the ulnar nerve. Clinical symptoms, physical examination findings, nerve conduction testing electromyography, plain radiography, and ultrasonography were evaluated before and after surgery. MRI was performed in 2 patients. Cyst decompression, disconnection of the articular branch, and ulnar nerve transposition were performed in all.

RESULTS

The mean follow-up was 29 months. After surgery, local elbow pain and Tinel sign disappeared in all patients, and the average Numerical Rating Scale dropped from 3.7 (2-5) to 0 (0-0). Two-point discrimination testing was normal (<5.0 mm) in 12 patients. Wartenberg sign and "claw hand" deformity became negative, and muscle function and motor nerve conduction velocity were improved in 12 patients. The Medical Research Council muscle strength grade was M4 or M5 in the flexor carpi ulnaris, flexor digitorum profundus of the 4th and 5th digits, and first dorsal interosseous muscle in 12 patients. Postoperative spontaneous potentials including fibrillation and sharp waves, and motor unit recruitment in the first dorsal interosseous muscle were obviously improved. A cystic articular branch was confirmed during surgery in all patients. No cyst recurred clinically or on follow-up ultrasonography.

CONCLUSION

The unifying articular theory of intraneural ganglion cysts applies to those located in the ulnar nerve at the elbow. Surgical disconnection of the articular nerve branch from the ulnar nerve eliminated the pathway for cyst recurrence and achieved good long-term outcomes.

7T for clinical imaging of benign peripheral nerve tumors: preliminary results

PURPOSE

MRI has become an essential diagnostic imaging modality for peripheral nerve pathology. Early MR imaging for peripheral nerve depended on inferred nerve involvement by visualizing downstream effects such as denervation muscular atrophy; improvements in MRI technology have made possible direct visualization of the nerves. In this paper, we share our early clinical experience with 7T for benign neurogenic tumors.

MATERIALS

Patients with benign neurogenic tumors and 7T MRI examinations available were reviewed. Cases of individual benign peripheral nerve tumors were included to demonstrate 7T MRI imaging characteristics. All exams were performed on a 7T MRI MAGNETOM Terra using a 28-channel receive, single-channel transmit knee coil.

RESULTS

Five cases of four pathologies were selected from 38 patients to depict characteristic imaging features in different benign nerve tumors and lesions using 7T MRI.

CONCLUSION

The primary advantage of 7T over 3T is an increase in signal-to-noise ratio which allows higher in plane resolution so that the smallest neural structures can be seen and characterized. This improvement in MR imaging provides the opportunity for more accurate diagnosis and surgical planning in selected cases. As this technology continues to evolve for clinical purposes, we anticipate increasing applications and improved patient care using 7T MRI for the diagnosis of peripheral nerve masses.

The current trend of proximal tibiofibular ganglion cyst: A summary of 7 case series and 61 case reports

Purpose

To review the different types of ganglion cysts surrounding the proximal tibio-fibular joint, their management options, outcomes, and recurrence.

Design

Descriptive analytical review.

Results

7 case series consisting of a total of 159 patients and 61 case reports consisting of 80 patients (with three patients having bilateral pathology) were included in this review. (Total cysts 159 + 83 = 242). The mean age was 41 years, and 71 % of the patients were males. 96.5 % of the cases were managed operatively, out of which 98 % of patients felt improvement in local symptoms and 71.5 % had improvement in neurological symptoms. Complete excision of the cyst is the primary mode of operative management. Many added procedures with complete excision are to mitigate the risk of recurrence. The recurrence rate of aspiration, simple excision alone, simple excision with recurrent articular branch neurectomy, and simple excision with PTFJ procedures were 77 %, 56 %, 11.5 %, and 0 %, respectively. Outcomes beyond recurrence were poorly reported.

Conclusion

There is not enough literature regarding the topic from which any formal systematic review can be done. Our summary suggests that aspiration alone or with steroid injection is associated with the highest recurrence rates among all the procedures. Complete excision with recurrent articular branch neurectomy should be the primary management. Revision cyst excision in isolation is an inadequate treatment option, therefore should be done in conjunction with PTFJ arthrodesis, which reduces the recurrence rates. Better quality studies are needed that report patient-centered outcomes and morbidities following PTFJ procedures.

Recurrent Peroneal Intraneural Ganglion Cyst: Management and Review of the Literature

Intraneural ganglion cysts have been reported to affect the common peroneal nerve. Peroneal intraneural ganglion cysts are managed through surgical intervention. Despite surgical intervention, intraneural ganglion cysts can recur. Common intraneural ganglion cyst recurrence patterns have been proposed based on the initial surgical management of the cyst. These patterns all emphasize the importance of treatment of the proximal tibiofibular (TF) joint to reduce the risk of cyst recurrence. Although joint resection is the favored intervention in the literature, joint arthrodesis is an option for certain patients. Here, we present a case of a peroneal intraneural ganglion cyst and its recurrence in a 36-year-old male who had previously undergone surgical removal of the cyst three months prior, as well as a review of the current literature that aims to add to our current understanding of intraneural cysts.

Imaging of Anatomical Variants of the Lower Limb Nerves: Clinical and Preoperative Relevance

Anatomical variants of peripheral nerves of the lower limb are relatively frequent and vulnerable to injury if not considered by the surgeon. Surgical procedures or percutaneous injections are often performed without knowing the anatomical situation. In a patient with normal anatomy, these procedures are mostly performed smoothly without major nerve complications. But in the case of anatomical variants, surgery may be challenging as "new" anatomical prerequisites complicate the procedure. In this context, high-resolution ultrasonography as the first-line imaging modality to depict peripheral nerves, has become a helpful adjunct in the preoperative setting. It is crucial, on the one hand, to gain knowledge of anatomical nerve variants and, on the other hand, to depict the anatomical situation preoperatively, to minimize the risk of surgical trauma to a nerve and make surgeries safer.

Intraneural or extraneural ganglion cysts as a cause of cubital tunnel syndrome: A retrospective observational study

Purpose

Cubital tunnel syndrome caused by ganglion cysts has rarely been reported. The purpose of this study was to evaluate the surgical treatment outcomes of a patient diagnosed with cubital tunnel syndrome caused by intraneural or extraneural cysts and to summarize our experience.

Method

In total, 34 patients were evaluated retrospectively from January 2011 to January 2020 with a follow-up of more than 24 months. Preoperative data, such as demographic data, clinical symptoms, physical examination findings, and laboratory tests, were all recorded and pre-operative and post-operative data were compared. The function was evaluated by the modified Bishop scoring system and the McGowan grade at the last follow-up.

Results

Improvement of interosseous muscle strength, the Visual Analog Scale (VAS), 2-point discrimination (2-PD), electromyogram (EMG) result, Wartenberg sign, claw hand, and weakness could be clearly observed in all patients. Extraneural cysts were completely removed and the pedicles of the cysts were ligated. Intraneural cysts were incised and drained, and part of their cyst walls were removed using a microsurgical technique. All patients underwent anterior subcutaneous transposition (AST). At the last follow-up, McGowan's (0-IIa) grade increased from seven patients (20.6%) preoperatively to 27 patients (79.4%); the excellent and good rate according to the modified Bishop scoring system was 82.4% (28 patients), and all patients had no symptoms of recurrence after surgery.

Conclusion

The treatment of cubital tunnel syndrome caused by intraneural or extraneural cysts achieved good long-term results through extraneural cyst resection or intraneural cyst incision and drainage combined with subcutaneous transposition. Early diagnosis and surgical treatment are essential for the patient's postoperative recovery.

Imaging of Entrapment Neuropathies in the Ankle

Entrapment neuropathies of the ankle and foot pose a major diagnostic challenge and thus remain underdiagnosed. Recent advancements in imaging modalities, including magnetic resonance neurography (MRN), have resulted in considerable improvement in the anatomical localization and identification of pathologies leading to nerve entrapment. MRN supplements clinical examination and electrophysiologic studies in the diagnosis of neuropathies, aids in assessing disease severity, and helps formulate management strategies. A comprehensive understanding of the anatomy and imaging features of the ankle is essential to diagnose and manage entrapment neuropathies accurately. Advancements in imaging and their appropriate utilization will ultimately lead to better diagnoses and improved patient outcomes.

Intraneural Ganglion of the Peroneal Nerve-A Rare Cause of Pediatric Peroneal Nerve Palsy: A Case Report

Intraneural ganglia are benign mucinous cysts located within the epineurium of a peripheral nerve. The pathogenesis and formation of intraneural ganglia are controversial. The main theories described in the literature are of degenerative, synovial or de novo occurrence. We present the case of a 14-year-old boy who presented in our outpatient clinic with a complaint of interdigital neuralgia between hallux and second toe, as well as left foot drop. MRI examination showed a hyperintense cystic distension of the common peroneal nerve measuring 130 mm × 5 mm extending from the poplitea to the anterior compartment of the leg. We performed microscopic decompression and neurolysis surgery. The cyst showed a sac-like distension at its distal end with connection to the tibiofibular joint and was resected. After 8 weeks, postoperatively, the boy claimed to be pain-free and slight recovery of the superficial peroneal nerve was noticed. At 6 months postoperative, the patient showed a continuous improvement of motor function, demonstrating foot eversion with 3/5 muscle strength and foot extension with 2/5 muscle strength. Intraneural ganglia reported for pediatric patients represent a very rare entity. To the best of our knowledge, less than 15 cases have been described within the English-speaking literature.

Intraneural ganglion cyst of the common peroneal nerve causing foot drop in a 12-year old child

OBJECTIVES

Intraneural ganglia are benign fluid-filled cysts contained within the subepineurial space of peripheral nerves. The common peroneal nerve at the fibular neck is by far the most frequently involved, although other nerves can be affected as well. Although the differential diagnosis of foot drop in adults and children show some differences, clinical presentation, diagnostic workup, treatment and follow-up of intraneural ganglia are quite similar in both groups. The primary objective was to create an overview of intraneural ganglia in children, with an emphasis on diagnostic workup and potential pitfalls during neurosurgical intervention, based on all available literature concerning this topic and own center experiences. As a secondary objective, we tried to raise the awareness concerning this unique cause of foot drop in childhood.

PATIENTS AND METHODS

We performed a review of the literature, in which children who developed foot drop secondary to an intraneural ganglion cyst of the common peroneal nerve were examined. A total of eleven articles obtained from MEDLINE were included. Search terms included: "pediatric", "children", "child", "intraneural ganglia", "intraneural ganglion cysts", "foot drop", "peroneal nerve" and "fibular nerve". Additional studies were identified by checking reference lists. Furthermore, we present the case of a 12-year old girl with foot drop caused by an intraneural ganglion cyst. She underwent cyst decompression with evacuation of intraneural cyst fluid and articular branch disconnection. PRISMA and CARE statement guidelines were followed.

RESULTS

We hypothesize that minor injury caused a breach in the joint capsule, resulting in synovial fluid egression along the articular nerve branch, corroborating the unifying articular theory and emphasizing the need for ligation of said branch. Foot drop is a predominant characteristic, explained by the proximity of the anterior tibial muscle motor branch near the articular branch nerve. In children, satisfactory motor recovery after surgical decompression is to be expected.

CONCLUSION

Sudden or progressive foot drop in children warrants an exhaustive neurophysiological and radiological workup. The management of intraneural ganglia is specific, consisting of nerve decompression, articular branch ligation and joint disarticulation, if deemed necessary. Our surgical results support the unifying articular theory and emphasize the importance of ligation and transection of the articular branch nerve, distally from the anterior tibial muscle branch, in order to prevent intraneural ganglia recurrence. This well-documented case adds depth to the current literature on this sparsely reported entity.

A novel mechanism for the formation and propagation of neural tumors and lesions through neural highways

By recognizing anatomic and radiologic patterns of rare and often misdiagnosed peripheral nerve tumors/lesions, we have defined mechanisms for the propagation of neural diseases. The novel concept of the nervous system serving as a complex system of "highways" driving the neural and perineural spread of these lesions is described in three examples: Intraneural dissection of joint fluid in intraneural ganglion cysts, perineural spread of cancer cells, and dissemination of unknown concentrations of neurotrophic/inhibitory factors for growth in hamartomas/choristomas of nerve. Further mapping of these pathways to identify the natural history of diseases, the spectrum of disease evolution, the role of genetic mutations, and how these neural pathways interface with the lymphatic, vascular, and cerebrospinal systems may lead to advances in targeted treatments.

The Addition of a Nerve Transfer to the Treatment of Peroneal Neuropathy Secondary to Intraneural Ganglion: Case Series

ABSTRACT

Peroneal intraneural ganglia are rare, and their management is controversial. Presently, the accepted treatment of intraneural ganglia is decompression and ligation of the articular nerve branch. Although this treatment prevents recurrence of the ganglia, the resultant motor deficit of foot drop in the case of intraneural peroneal ganglia is unsatisfying. Foot drop is classically treated with splinting or tendon transfers to the foot. We have recently published a case report of a peroneal intraneural ganglion treated by transferring a motor nerve branch of flexor hallucis longus into a nerve branch of tibialis anterior muscle in addition to articular nerve branch ligation and decompression of the intraneural ganglion to restore the patient's ability to dorsiflex. We have since performed this procedure on 4 additional patients with appropriate follow-up. Depending on the initial onset of foot drop and time to surgery, nerve transfer from flexor hallucis longus to anterior tibialis nerve branch may be considered as an adjunct to decompression and articular nerve branch ligation for the treatment of symptomatic peroneal intraneural ganglion.

High-resolution MRI of a peroneal intraneural ganglion cyst arising from the knee joint: illustrative case

BACKGROUND

The advancement of high-resolution imaging and increased clinical experience have led to an increased understanding of the formation and treatment of intraneural ganglion cysts. Nearly all intraneural ganglion cysts in the common peroneal nerve have been reported to arise from a joint connection to the superior tibiofibular joint. The authors have identified four cases of intraneural ganglion cysts arising from the knee joint itself; however, none of these reported cases were well described, documented, or illustrated with high-resolution imaging.

OBSERVATIONS

Here the authors present the case of an intraneural ganglion cyst arising from the knee joint and causing intermittent weakness and pain. The articular branch to the knee joint was clearly demonstrated on high-resolution magnetic resonance imaging and confirmed at surgical exploration. The patient was treated with articular branch ligation and has had complete resolution of his symptoms without recurrence of the cyst on follow-up imaging.

LESSONS

This case adds to the mounting evidence that intraneural cyst pathology is dependent on a connection to a synovial joint as stated in the unifying theory of intraneural cyst development.

The articular branch of the peroneal nerve to the proximal tibiofibular joint descends at a mean height of approximately 18 mm distal to the postero-lateral tip of the fibular head

PURPOSE

The aim of the study was to evaluate the anatomical details of the articular branch of the peroneal nerve to the proximal tibiofibular joint and to project the height of its descent in relation to the fibular length.

METHODS

Twenty-five lower extremities were included in the study. Following identification of the common peroneal nerve, its course was traced to its division into the deep and superficial peroneal nerve. The articular branch was identified. The postero-lateral tip of the fibular head was marked and the interval from this landmark to the diversion of the articular branch was measured. The length of the fibula, as the interval between the postero-lateral tip of the fibular head and the tip of the lateral malleolus, was evaluated. The quotient of descending point of the articular branch in relation to the individual fibular length was calculated.

RESULTS

The articular branch descended either from the common peroneal nerve or the deep peroneal nerve. The descending point was located at a mean height of 18.1 mm distal to the postero-lateral tip of the fibular head. Concerning the relation to the fibular length, this was at a mean of 5.1%, starting from the same reference point.

CONCLUSION

The articular branch of the common peroneal nerve was located at a mean height of 18.1 mm distal to the the postero-lateral tip of the fibular head, respectively, at a mean of 5.1% of the whole fibular length starting from the same reference point. These details represent a convenient orientation during surgical treatment of intraneural ganglia of the common peroneal nerve, which may result directly from knee trauma and indirectly from ankle sprain.

Intraneural ganglion cysts of the peroneal nerve

BACKGROUND

Intraneural ganglion cysts of the peroneal nerve are rare, and there is lack of evidence for the surgical management of this entity. We performed this study to evaluate the imaging, diagnosis, treatment and outcome of seven patients with intraneural ganglion cysts of the peroneal nerve.

MATERIALS AND METHODS

We retrospectively studied the files of seven patients with intraneural ganglion cysts of the peroneal nerve, diagnosed and treated from 2016 to 2019. Diagnostic approach included clinical examination of the leg and foot, magnetic resonance imaging, nerve conduction studies, surgical excision of the cyst and histological examination. The mean follow-up was 2 years (range 1-3.5 years). We evaluated the time and methods for surgical treatment, and the clinical outcomes of the patients.

RESULTS

All patients presented symptoms of peripheral compression neuropathy; three patients presented with foot drop. The intraneural ganglion cysts were excised in all cases in addition to knee articular nerve branch transection to avoid cysts recurrence. Postoperatively, all patients experienced complete neurological recovery without clinical evidence of intraneural ganglion cysts recurrences.

CONCLUSION

The treating physicians should be aware of intraneural ganglion cysts of the peroneal nerve in patients presenting with limb weakness, sensory deficits at the lateral and anterior side of the leg and foot, paresis or paralysis of the foot and ankle. MR imaging is the imaging modality of choice for a clear and accurate preoperative diagnosis to avoid misdiagnosis and wrong treatment. In case of doubt, these patients should be managed in an orthopedic oncology setting with microsurgery facilities available for complete excision of the intraneural ganglion cyst.

Detailed Case Reports of Surgical Treatment for Intraneural Ganglion Cysts

Intraneural ganglion cysts are nonneoplastic mucinous cysts that form by the accumulation of thick mucinous fluid in the epineurium of peripheral nerves. Symptoms arise from mechanical compression of adjacent nerve fascicles from the intraneural ganglion cyst, and include local or radiating pain, paresthesias, weakness, and muscle atrophy.

Drop Foot Secondary to a Peroneal Intraneural Ganglion Connected to the Superior Tibiofibular Joint: A Case Report

Peroneal neuropathy is the most frequent mononeuropathy of the lower extremity. Intraneural ganglion cysts (INGCs) are among rare causes of peroneal nerve palsy. According to the articular (synovial) theory, the articular branch plays the key role in the pathogenesis. Patients present with pain around the fibular head and neck, motor weakness resulting in foot drop and paresthesia in the anterolateral calf and foot. Ultrasonography (US) and MRI are both useful in the diagnosis, but MRI is the best imaging modality in the demonstration of the articular connection and the relation of the cyst with adjacent structures, even without special neurography sequences. We present a 32-year-old male patient referred to our neurosurgery clinic with suspicion of lumbar radiculopathy. He presented with right foot drop which began 3 weeks prior. On examination, there was 90% loss in the ankle dorsiflexion and finger extension. Ankle eversion was also weakened. There was no low back or posterolateral thigh pain to suggest L5 radiculopathy and sciatic neuropathy. Following negative lumbar spine MRI, peripheral neuropathy was concerned. Electrodiagnostic evaluations findings were consistent with acute/subacute common peroneal nerve (CPN) axonal neuropathy. Subsequent MRI of knee showed a homogeneous, thin-walled tubular cystic lesion, extending along the course of the CPN and its articular branch. Full recovery of the neuropathy was achieved with early diagnosis and decompression via microsurgical epineurotomy. The diagnosis of INGC was confirmed by histopathologic examination. INGCs, although rare, should also be considered in the differential diagnosis of peripheral mononeuropathies.

[A case of tibial nerve palsy due to intraneural ganglion cysts]

A 39-year-old man presented with an 8-month history of pain and paresthesia of the right foot sole and difficulty in the right toe dorsiflexion. A neurological examination revealed weakness in performing both the ankle and right foot toe dorsiflexion, reduced right planta pedis sensation, and absent right Achilles tendon reflex. Tinel's sign was present on the right popliteal fossa and medial part of the right ankle. MRI of the right knee showed multiple cystic lesions in his right tibial nerve. The cystic lesions extended from the popliteal fossa and were thought to be intraneural ganglion cysts. On MRI performed 4 months later, most of the cystic lesions spontaneously vanished. Therefore, intraneural ganglia should be considered when atypical mononeuropathy, such as tibial nerve palsy, is present.

Mimickers of Carpal Tunnel Syndrome

Carpal tunnel syndrome is the most common compression neuropathy. Despite the prevalence of carpal tunnel syndrome, many other conditions present with similar symptoms (numbness, tingling, thenar atrophy, and weakness). Carpal tunnel syndrome is differentiated from other etiologies through a detailed history and physical examination, aided by electrodiagnostic and adjunctive imaging studies. Misdiagnosis can lead to unnecessary operative procedures and persistent symptoms.

The medial safe zone for treating intraneural ganglion cysts in the tarsal tunnel: a technical note

INTRODUCTION

Intraneural ganglion cysts in the tarsal tunnel are rare but are being increasingly reported. The cysts involve the tibial or plantar nerves and are most commonly derived from a neighboring (degenerative) joint, (i.e., the tibiotalar or subtalar) via an articular branch arising from the medial aspect of the nerve. We describe a safe zone for approaching these cysts in the tarsal tunnel that allows for identification of the joint connection without injury to important distal branches.

METHODS

We present a case of an intraneural ganglion cyst within the tarsal tunnel in a patient with symptoms consistent with tarsal tunnel syndrome. Using intraoperative photographs and artist rendering, we describe a technique to safely disconnect the abnormal joint connection while preserving the important distal branches of the tibial nerve.

CONCLUSION

The safe zone for the tibial nerve in the tarsal tunnel can be exposed by mobilization and gentle retraction of the vascular bundle. In cases of intraneural ganglion cysts, all apparent connections between the nerve and degenerative joints within this safe zone can be resected without injury to important distal nerve branches.

Intraneural ganglion cyst: a case report and a review of the literature

Background

An intraneural ganglion cyst is a non-neoplastic gelatinous cyst, which can be found within the epineurium of a peripheral nerve and lead to signs and symptoms of peripheral neuropathy. Early diagnosis and appropriate surgical treatment of this condition is a key to a successful outcome.

Materials and methods

We describe a case of a patient with peroneal nerve neuropathy caused by an intraneural ganglion cyst. Postsurgically, only partial relieve of the symptoms was achieved because of delayed diagnosis.

Results

The aetiology of intraneural ganglia is controversial and historically different pathogeneses of this condition have been described. Diagnosis of these cysts is based on MRI. Multiple surgical treatment strategies have been developed based on different pathogenesis of the formation of these cysts, but neuropathy is reversible only, if this condition is diagnosed and treated early.

Intraneural Synovial Cyst of the Common Peroneal Nerve: An Unusual Cause of Foot Drop with Four-Year Follow-Up

In our case report, we describe a 55-year-old male patient with isolated foot drop due to an intraneural synovial ganglion. We successfully treated the lesion with decompression via epineurotomy combined with primary division of the recurrent articular branch of the common peroneal nerve (CPN). Compression neuropathies of the common peroneal nerve arise from a variety of causes. Intrinsic compression due to intraneural ganglion cysts of the CPN is rare. Previous reports of simple decompression of the cystic fluid have resulted in recurrence. The unified articular theory describes a pathway for fluid to fill from the proximal tibiofibular joint into the CPN via a recurrent articular branch. In our case, we divide this articular branch which we feel prevents recurrence.

Surgical Treatment of Intraneural Ganglion Cysts of the Ulnar Nerve at the Elbow: Long-Term Follow-up of 9 Cases

BACKGROUND

Intraneural ganglion (IG) cysts have been considered curiosities and their pathogenesis remains controversial.

OBJECTIVE

To clarify ulnar nerve at the elbow (UNE) pathogenesis and long-term surgical outcomes by presenting 9 rare cases of IG of the UNE.

METHODS

Surgical treatment of IG was performed. Clinical symptoms, physical examinations, and electromyogram were evaluated pre- and postoperatively. At least 4 yr of follow-up was performed.

RESULTS

The Tinel's sign became negative and local elbow pain disappeared in all 9 patients after surgery, and the average visual analog scale/score dropped from 4.9 (3-8) to 0 (0-0) after 6.2 d (2-10) on average. Two patients retained positive Froment test, “claw hand” and paresthesias with the 2-point discrimination much different from the contralateral little finger. Postoperative the UK Medical Research Council muscle strength score (MRC) grades of the flexor carpi ulnaris and the flexor digitorum profundus muscle of the fourth and fifth digits recovered to M4-M5 from M0-M2 in all 9 patients. The postoperative MRC grades of the third to fourth lumbrical muscles, the interossei, and the hypothenar recovered to M3-M5 from M0-M2 in 7 patients. Cystic articular branch (CAB) was found in all 9 patients intraoperatively. No symptomatic recurrence of IG was seen. The mean motor nerve conduction velocity of ulnar nerve across the elbow recovered from 5.3 to 41.2 m/s.

CONCLUSION

A unifying articular theory is responsible for the pathogenesis of IG of UNE and disconnection of the CAB would prevent recurrence. The long-term outcome is good after surgical treatment of IG of UNE.

Intraneural Ganglion Cyst of the Sciatic Nerve Treated Using Arthroscopic Hip Surgery: A Case Report

This is a rare case of sciatic neuropathy in a 46-year-old man secondary to an intraneural ganglion cyst from the hip joint extending upward to the lumbar plexus and the L5 nerve root. Magnetic resonance neurography showed that the joint fluid passed through a labral tear and extended rostrally along the articular branch and the peroneal portion of the sciatic nerve to near the L5 nerve root. The condition was treated by arthroscopic disruption of the joint connection to the nerve with resolution of the intraneural cyst and partial neurological recovery.

Cystic Adventitial Disease of the Tibial Vein Arising From the Subtalar Joint: A Case Report

Soft tissue ganglion cysts are a well-known cause of tibial nerve compression in the tarsal tunnel. We describe a patient who presented with tibial nerve symptoms and was found to have an adventitial cyst of the tibial vein arising from the subtalar joint, with the joint connection confirmed both on imaging and at surgery. Surgical decompression of the cyst with transection of the vascular pedicle arising from the subtalar joint improved her symptoms at 6 months, and postoperative magnetic resonance imaging showed resolution of the cyst. Cystic adventitial disease is a rare, poorly understood condition in which a cyst is identified in the adventitia of a vessel, usually an artery. Only 3 cases of adventitial cysts have been reported in the foot and ankle region, 2 in the lesser and 1 in the greater saphenous vein. None of the previous cases have been recognized to be joint connected. This case provides additional evidence for an articular origin for adventitial cysts and helps guide management strategies for these joint-connected cysts.

Peripheral nerve injuries in the pediatric population: a review of the literature. Part III: peripheral nerve tumors in children

INTRODUCTION

Peripheral nerve tumors type, inciedence and treatment in the pediatric population should be analyzed.

METHODS

We have performed an extense literature review of this subject.

RESULTS

incidence and distribution are similar to those observed in adults. The most common peripheral nerve tumors in children are neurofibromas and schwannomas. Malignant peripheral nerve sheath tumors are also observed, specially associated with genetic syndromes, like neurofibromatosis and Carney complex.

CONCLUSION

In this review, peripheral nerve tumors have been divided into three categories to aid with understanding: reactive and hyperplastic lesions, benign tumors, and malignant tumors. The most frequent lesions have been described.

Retracing the observations and footsteps of Beauchêne fils: A blueprint for scientific research

Throughout the years, scientific and personal research has led us on a historical journey to learn about the life of Beauchêne fils (Edme François Chauvot de Beauchêne), a French clinical anatomist, prosector, and surgeon responsible for introducing the disarticulated skull technique and the first citation of an intraneural cyst. This letter describes our research, travels, and conversations intended to uncover the fascinating history of Beauchêne fils and his family and our journey full of unexpected twists and turns. During a trip to Paris, we learned of a possible inspiration for the disarticulated skull technique from skulls afflicted with la teigne (Tinea corporis, ring worm) at the Musée Dupuytren. We toured the estate of his family's summer home in Paron, France, where we discovered a portrait of Beauchêne fils' father that had been misidentified in our recent publication. We also discovered the date of death and elusive burial site of Beauchêne fils in Père Lachaise cemetery in Paris. We hope to bring to light the life and contributions of a nearly unknown figure who influenced not only research on intraneural ganglion cysts and the articular theory, but also the future of the field of anatomy. Clin. Anat. 31:1194-1198, 2018. © 2018 Wiley Periodicals, Inc.

Immediate Nerve Transfer for Treatment of Peroneal Nerve Palsy Secondary to an Intraneural Ganglion: Case Report and Review

Intraneural ganglion cysts, which occur within the common peroneal nerve, are a rare cause of foot drop. The current standard of treatment for intraneural ganglion cysts involving the common peroneal nerve involves (1) cyst decompression and (2) ligation of the articular nerve branch to prevent recurrence. Nerve transfers are a time-dependent strategy for recovering ankle dorsiflexion in cases of high peroneal nerve palsy; however, this modality has not been performed for intraneural ganglion cysts involving the common peroneal nerve. We present a case of common peroneal nerve palsy secondary to an intraneural ganglion cyst occurring in a 74-year-old female. The patient presented with a 5-month history of pain in the right common peroneal nerve distribution and foot drop. The patient underwent simultaneous cyst decompression, articular nerve branch ligation, and nerve transfer of the motor branch to flexor hallucis longus to a motor branch of anterior tibialis muscle. At final follow-up, the patient demonstrated complete (M4+) return of ankle dorsiflexion, no pain, no evidence of recurrence and was able to bear weight without the need for orthotic support. Given the minimal donor site morbidity and recovery of ankle dorsiflexion, this report underscores the importance of considering early nerve transfers in cases of high peroneal neuropathy due to an intraneural ganglion cyst.

Peroneal Nerve Palsy Due to Subparaneurial Ganglion Cyst, a Rare Variant of Intraneural Ganglion Cyst

Intraneural ganglion cysts are rare mucinous cysts originating within the epineurium of peripheral nerves. Although ganglion cysts are the most frequent tumors of the upper and lower extremities, ganglion cysts rarely result in peripheral nerve compression. We report a case of a 30-year-old patient who presented with foot drop due to subparaneurial ganglion cyst, a variant of an intraneural ganglion cyst. Characteristic magnetic resonance imaging findings were essential in the preoperative diagnosis of intraneural ganglion cyst. The common peroneal nerve and its branches were recognized and traced to its bifurcation during the operation. The articular branches were addressed. The mucious content of the ganglion was typically found to be located within the subparaneurial compartment. Incision of the subparaneurial ganglion cyst was performed, and mucinous content was evacuated. At 2 months after the surgery, paralyzed peroneal nerve was recovered completely. Therefore, early diagnosis of intraneural ganglion, precise identification of the pathology, and proper treatment of the articular branch with atraumatic dissection of ganglion cyst are essential in the successful management of this rare lesion.

Cubital tunnel syndrome caused by ganglion cysts: a review of 59 cases

BACKGROUND

Cubital tunnel syndrome caused by ganglion cysts is rare and reports are few. This study aimed to review a patient cohort with ganglion cysts in the cubital tunnel and identify prognostic factors.

METHODS

Fifty-seven patients (59 extremities; McGowan grade I, 4; IIa, 4; IIb, 3; III, 48) were evaluated retrospectively with a minimum follow-up of 2 years. Extraneural cysts were excised completely, while intraneural cysts were incised and drained. All cases underwent subcutaneous transposition. Spearman's rank correlation and the ordinal logistic regression model were used to assess the effect of independent variables on the postoperative McGowan grade.

RESULTS

VAS pain and weakness, 2-PD, key-pinch strength, grip strength, first dorsal interosseous muscle strength, Wartenberg sign, and claw hand all improved significantly. DASH scores improved from an average of 43.8 points preoperatively to 10.7 points postoperatively. According to the modified Bishop scoring system, 55 extremities (93.2%) were graded good or excellent. At the last follow-up, 29 hands (49.2%) returned to normal, and improvement by at least one McGowan grade was reached in 51 cases (86.4%). Older age, smoking, and shorter postoperative follow-up were associated with a higher postoperative McGowan grade.

CONCLUSIONS

Satisfactory surgical outcomes could be expected in these patients following subcutaneous transposition with excision of extraneural cysts and draining of intraneural cysts. Older age, smoking, and shorter postoperative follow-up were found to be independent risk factors for poor outcomes.

Cystic lesions of peripheral nerves: Are we missing the diagnosis of the intraneural ganglion cyst?

AIM

To highlight the salient magnetic resonance imaging (MRI) features of the intraneural ganglion cyst (INGC) of various peripheral nerves for their precise diagnosis and to differentiate them from other intra and extra-neural cystic lesions.

METHODS

A retrospective analysis of the magnetic resonance (MR) images of a cohort of 245 patients presenting with nerve palsy involving different peripheral nerves was done. MR images were analyzed for the presence of a nerve lesion, and if found, it was further characterized as solid or cystic. The serial axial, coronal and sagittal MR images of the lesions diagnosed as INGC were studied for their pattern and the anatomical extent along the course of the affected nerve and its branches. Its relation to identifiable anatomical landmarks, intra-articular communication and presence of denervation changes in the muscles supplied by involved nerve was also studied.

RESULTS

A total of 45 cystic lesions in the intra or extraneural locations of the nerves were identified from the 245 MR scans done for patients presenting with nerve palsy. Out of these 45 cystic lesions, 13 were diagnosed to have INGC of a peripheral nerve on MRI. The other cystic lesions included extraneural ganglion cyst, paralabral cyst impinging upon the suprascapular nerve, cystic schwannoma and nerve abscesses related to Hansen's disease involving various peripheral nerves. Thirteen lesions of INGC were identified in 12 patients. Seven of these affected the common peroneal nerve with one patient having a bilateral involvement. Two lesions each were noted in the tibial and suprascapular nerves, and one each in the obturator and proximal sciatic nerve. An intra-articular connection along the articular branch was demonstrated in 12 out of 13 lesions. Varying stages of denervation atrophy of the supplied muscles of the affected nerves were seen in 7 cases. Out of these 13 lesions in 12 patients, 6 underwent surgery.

CONCLUSION

INGC is an important cause of reversible mono-neuropathy if diagnosed early and surgically treated. Its classic MRI pattern differentiates it from other lesions of the peripheral nerve and aid in its therapeutic planning. In each case, the joint connection has to be identified preoperatively, and the same should be excised during surgery to prevent further cyst recurrence.

Immediate Nerve Transfer for the Treatment of Peroneal Nerve Palsy Secondary to an Intraneural Ganglion: Case Report and Review

Intraneural ganglion cysts that occur within the common peroneal nerve are a rare cause of foot drop. The current standard of treatment for intraneural ganglion cysts involving the common peroneal nerve involves (1) cyst decompression and (2) ligation of the articular nerve branch to prevent recurrence. Nerve transfers are a time-dependent strategy for recovering ankle dorsiflexion in cases of high peroneal nerve palsy; however, this modality has not been performed for intraneural ganglion cysts involving the common peroneal nerve. We present a case of common peroneal nerve palsy secondary to an intraneural ganglion cyst occurring in a 74-year-old female. The patient presents with a 5-month history of pain in the right common peroneal nerve distribution and foot drop. The patient underwent simultaneous cyst decompression, articular nerve branch ligation, and nerve transfer of the motor branch to the flexor hallucis longus to a motor branch of the anterior tibialis muscle. At final follow-up, the patient demonstrated complete (M4+) return of ankle dorsiflexion, no pain, and no evidence of recurrence and was able to weight bare without the need of orthotic support. Given the minimal donor site morbidity and recovery of ankle dorsiflexion, this report underscores the importance of considering early nerve transfers in cases of high peroneal neuropathy due to an intraneural ganglion cyst.

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.

An Unusual Cause of Foot Drop: Peroneal Extraneural Ganglion Cyst

Peripheral neuropathies caused by ganglion cysts are quite rare, especially in the lower extremities. The case of a 64-year-old male with a 2-day history of foot drop and tenderness in the region of the left fibular neck is presented. Physical examination and electromyogram findings verified peroneal nerve palsy. Ultrasonography showed cystic mass localized proximal of the peroneal muscle structures. Magnetic resonance imaging revealed a cystic-appearing mass around the fibular neck that compressed the common peroneal nerve. Surgical excision and ligation of the cyst pedicle were performed. The pathology reports confirmed the diagnosis of a ganglion cyst. The patient regained full function within two months of the surgery. Early sensory symptoms before foot drop should be considered as an indication of surgical excision to prevent delayed damage. Ligation or electrocoagulation of the cyst pedicle should be a part of surgical procedure to avoid recurrences.

Intraneural Ganglion Cyst of the Ulnar Nerve at the Elbow Masquerading as a Malignant Peripheral Nerve Sheath Tumor

BACKGROUND

Ulnar neuropathy at the elbow (UNE) is the second most common mononeuropathy of the upper extremity. One rare cause of UNE is nerve mass lesions, including intraneural ganglion cysts (IGCs). IGC imaging studies provide important information that may determine the nature of a peripheral nerve mass lesion.

CASE DESCRIPTION

We present the case of a 73-year-old woman who presented with rapid deterioration of left hand function over 2 months with weakness of fine motor control, grip strength, and dysesthesia in the ulnar nerve distribution. Preoperative imaging studies, including magnetic resonance imaging (MRI) of the elbow, postcontrast studies, diffusion-weighted imaging, and apparent diffusion coefficient measurements, suggested a highly cellular tumor. Diffusion tensor tractography also revealed imaging features suggestive of a malignant peripheral nerve sheath tumor. During the operation, a sample of the lesion was sent for frozen section. There were no features of malignancy, and the pathologist could not determine a diagnosis based on the tissue sample sent. An intraoperative decision was made not to divide the ulnar nerve above and below the lesion. The IGC was successfully managed by identifying a suitable plane of dissection and cyst resection.

CONCLUSIONS

This case demonstrates that MRI studies indicating malignant peripheral nerve sheath tumor must be considered with some caution and corroborated with supportive features on operative inspection and biopsy before radical resection is undertaken. Furthermore, for any nerve mass lesion immediately adjacent to a joint, the differential diagnosis of an IGC should be considered.

Advances in the neurological and neurosurgical management of peripheral nerve trauma

Peripheral nerve trauma frequently affects younger people and may result in significant and long-lasting functional disability. Currently, diagnosis and monitoring of peripheral nerve injury relies on clinical and electrodiagnostic information, supplemented by intraoperative electrophysiological studies. However, in a significant proportion of nerve injuries, the likelihood of spontaneous regeneration resulting in good functional outcome remains uncertain and unnecessary delays to treatment may be faced while monitoring for recovery. Advances in non-invasive imaging techniques to diagnose and monitor nerve injury and regeneration are being developed, and have the potential to streamline the decision-making process. In addition, advances in operative and non-operative treatment strategies may provide more effective ways to maximise functional outcomes following severe peripheral nerve trauma. This review discusses these advances in light of the current state of the art of management of peripheral nerve trauma.

Intraneural ganglion cysts: a systematic review and reinterpretation of the world's literature

OBJECTIVE The etiology of intraneural ganglion cysts has been controversial. In recent years, substantial evidence has been presented to support the articular (synovial) theory for their pathogenesis. The authors sought to 1) perform a systematic review of the world's literature on intraneural cysts, and 2) reinterpret available published MR images in articles by other authors to identify unrecognized joint connections. METHODS In Part 1, all cases were analyzed for demographic data, duration of symptoms, the presence of a history of trauma, whether electromyography or nerve conduction studies were performed, the type of imaging, surgical treatment, presence of a joint connection, intraneural cyst recurrence, and postoperative imaging. Two univariate analyses were completed: 1) to compare the proportion of intraneural ganglion cyst publications per decade and 2) to assess the number of recurrences from 1914 to 2003 compared with the years 2004-2015. Three multivariate regression models were used to identify risk factors for intraneural cyst recurrence. In Part 2, the authors analyzed all available published MR images and obtained MR images from selected cases in which joint connections were not identified by the original authors, specifically looking for unrecognized joint connections. Two univariate analyses were done: 1) to determine a possible association between the identification of a joint connection and obtaining an MRI and 2) to assess the number of joint connections reported from 1914 to 2003 compared with 2004 to 2015. RESULTS In Part 1, 417 articles (645 patients) were selected for analysis. Joint connections were identified in 313 intraneural cysts (48%). Both intraneural ganglion cyst cases and cyst recurrences were more frequently reported since 2004 (statistically significant difference for both). There was a statistically significant association between cyst recurrence and percutaneous aspiration as well as failure to disconnect the articular branch or address the joint. In Part 2, the authors identified 43 examples of joint connections that initially went unrecognized: 27 based on their retrospective MR image reinterpretation of published cases and 16 of 16 cases from their sampling of original MR images from published cases. Overall, joint connections were more commonly found in patients who received an MRI examination and were more frequently reported during the years 2004 to 2015 (statistically significant difference for both). CONCLUSIONS This comprehensive review of the world's literature and the MR images further supports the articular (synovial) theory and provides baseline data for future investigators.

Peripheral nerve imaging

Disorders of peripheral nerve have been traditionally diagnosed and monitored using clinical and electrodiagnostic approaches. The last two decades have seen rapid development of both magnetic resonance imaging (MRI) and ultrasound imaging of peripheral nerve, such that these imaging modalities are increasingly invaluable to the diagnosis of patients with peripheral nerve disorders. Peripheral nerve imaging provides information which is supplementary to clinical and electrodiagnostic diagnosis. Both MRI and ultrasound have particular benefits in specific clinical circumstances and can be considered as complementary techniques. These technologic developments in peripheral nerve imaging will usher in an era of multimodality assessment of peripheral nerve disorders, with clinical evaluations supported by anatomic information from imaging, and functional information from electrodiagnostic studies. Such a multimodality approach will improve the accuracy and efficiency of patient care.

Recurrent intraneural ganglion cysts: Pathoanatomic patterns and treatment implications

The etiology of intraneural ganglion cysts has been poorly understood. This has resulted in the development of multiple surgical treatment strategies and a high recurrence rate. We sought to analyze these recurrences in order to provide a pathoanatomic explanation and staging classification for intraneural cyst recurrence. An expanded literature search was performed to identify frequencies and patterns in cases of intraneural ganglion cyst recurrences following primary surgery. Two univariate analyses were completed to identify associations between the type of revision surgery and repeat cyst recurrences. The expanded literature search found an 11% recurrence rate following primary surgery, including 64 recurrences following isolated cyst decompression (Group 1); six after articular branch resection (Group 2); and none following surgical procedures that addressed the joint (Group 3). Eight cases did not specify the type of primary surgery. In group 1, forty-eight of the recurrences (75%) were in the parent nerve, three involved only the articular branch, and one travelled along the articular branch in a different distal direction without involving the main parent nerve. In group 2, only one case (17%) recurred/persisted within the parent nerve, one recurred within a persistent articular branch, and one formed within a persistent articular branch and travelled in a different distal direction. Intraneural recurrences most commonly occur following surgical procedures that only target the main parent nerve. We provide proven or theoretical explanations for all identified cases of intraneural recurrences for an occult or persistent articular branch pathway.