Application of three-dimensional rendering in joint-related ganglion cysts

The value of high-resolution imaging in an occult peroneal intraneural ganglion cyst: illustrative case

BACKGROUND

Foot drop is a common complaint with a broad differential diagnosis making imaging a key part of the diagnostic workup. The authors present a patient with an occult peroneal intraneural ganglion cyst who underwent imaging with high-frequency ultrasound (US) and high-resolution magnetic resonance imaging (MRI) to highlight the role of such techniques in cases of peroneal neuropathy.

OBSERVATIONS

Intraneural ganglion cysts are emerging as a common cause of common peroneal neuropathy. Imaging with US and MRI is a valuable tool used to illustrate the pertinent anatomy and identify the articular branch joint connection and cyst as part of the surgical planning and definitive management.

LESSONS

Intraneural ganglion cysts can be small or nearly invisible and failure to appreciate the intraneural cyst can lead to symptom or cyst persistence or recurrence. High-resolution modalities can be useful in the diagnosis and surgical planning of difficult cases.

Prevalence of Ganglion Cyst Formation After Wrist Arthroscopy: A Retrospective Longitudinal Analysis of 2420 Patients

BACKGROUND

Dorsal wrist ganglion cysts arise from the leakage of synovial fluid through tears in the scapholunate ligament and/or dorsal wrist capsule. An analogous disruption of the dorsal capsule is created with routine portal placement during wrist arthroscopy. We hypothesized that wrist arthroscopy would predispose to wrist ganglions.

METHODS

Using the Truven MarketScan Outpatient Services Database from 2015 to 2016, patients who underwent wrist arthroscopy and developed an ipsilateral wrist ganglion were identified. Exclusion criteria included ganglion diagnosis preceding arthroscopy and bilateral pathology. Postoperative ganglion diagnosis was modeled with logistic regression. Predictor variables included age, gender, comorbidities, and arthroscopic procedure.

RESULTS

In all, 2420 patients underwent wrist arthroscopy. Thirty (1.24%) were diagnosed with an ipsilateral wrist ganglion at a mean time of 4.0 months (standard deviation: 2.4, range: 0.2-9.0). Significant predictors of ganglion diagnosis included female gender (odds ratio [OR]: 4.0, P < .01) and triangular fibrocartilage complex and/or joint debridement (OR: 0.13, P < .01). By comparison, among all 24,718,751 outpatients who had not undergone wrist arthroscopy, 39,832 patients had a diagnosis of a wrist ganglion cyst (0.16%).

CONCLUSIONS

Wrist arthroscopy is associated with a postoperative rate of ganglion cyst formation that is nearly 8 times the rate in the general population. Additional studies are needed to investigate techniques that minimize the risk of this complication.

Adventitial cystic disease of the common femoral vein: an unusual cause of lower extremity swelling and review of the literature

We report the case of a 61-year-old man who had presented with acute unilateral limb swelling. Computed tomography venography and duplex ultrasound demonstrated compression of the right common femoral vein by a common femoral vein adventitial cyst. Before intervention, the patient had developed an acute deep vein thrombosis of the right common femoral vein and great saphenous vein. Preoperative magnetic resonance imaging demonstrated concern for synovial connection. After 6 months of anticoagulation therapy, the patient underwent adventitial cyst excision with ligation of the hip joint articular connection. At 4 months postoperatively, the patient was symptom free without cyst recurrence. The findings from the present case support the synovial theory for adventitial cystic disease.

Giant intraosseous ganglion of the fibula: multimodality imaging

Intraosseous ganglia around the knee are most commonly located in the proximal tibia and limited to the epiphyseal-metaphyseal region. We report the case of a giant intraosseous ganglion of the fibula. MRI demonstrated the fluid avascular content of the lesion. CT arthrography of the knee demonstrated partial opacification of the lesion through a cortical bone defect. The lesion was treated with curettage and bone grafting. Anatomopathological examination confirmed the medical imaging diagnosis of intraosseous ganglion. This case highlights the value of joint opacification with CT arthrography to demonstrate the communication between the articular cavity and the ganglion.

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 neuropathy caused by joint-related cysts: a review of 17 cases

BACKGROUND

Clinical compression neuropathy caused by para-articular cysts is rare. Only recently, the unifying articular theory was proposed to clarify its true etiologic nature. The authors attribute 17 cases to this theory in order to illustrate the shift in the diagnostic and treatment protocol, and the possible impact on patient outcome.

METHODS

Eight intraneural and nine extraneural cysts were included. The proposed diagnostic protocol includes electromyography and ultrasound, followed by magnetic resonance imaging to characterize the cyst. The proposed treatment protocol consists of (1) ligation of the pedicle connecting the cyst with the afflicted joint, (2) decompression of the nerve and, when needed and (3) disarticulation of the superior tibiofibular joint (in case of peroneal nerve involvement).

RESULTS

Outcome was good to excellent in all patients, with recovery of sensory and motor function. Cyst recurrence was observed in three intraneural cases (18 %). Analysis of our own diagnostic protocol showed that atypical compression neuropathies should follow a strict diagnostic protocol to exclude missing the presence of a cyst. Ultrasound needs to play a crucial role, with MRI for cyst characterization and pedicle identification.

CONCLUSIONS

Retrospective proof in favor of the articular theory was found in all cases. An explanation for the cyst recurrences was formed based on the articular theory. In addition, a diagnostic and therapeutic protocol is proposed for all atypical peripheral compression neuropathies with the ultimate goal to achieve optimal patient outcome.

Operative treatment for ganglion cysts of the foot and ankle

The authors analyzed the clinical results of surgical excision for symptomatic or recurrent ganglion cysts of the foot and ankle, and tried to elucidate the prognostic factors. Fifty-three cases of ganglions in the foot and ankle were followed for more than 24 months after excision. The mean duration of follow-up was 3.7 years. As a preceding treatment, 17 cases received a mean of 1.3 aspirations, and 16 cases recurred after a mean of 1.7 operations. The cyst was most common in the dorsum of the foot and ankle, where 35 cases were found. Thirty cases originated from the tendon sheath, 19 cases from the joint, and 4 cases from others. Preoperative mean AOFAS foot scores were low in the cysts associated with the tarsal tunnel syndrome, and in the cysts of the plantar aspect of the first toe. Postoperative mean AOFAS foot scores were significantly increased in the preceding 2 groups. There were 3 (5.7%) cases of recurrence, all of which originated from the tendon sheath. In the case of ganglion cysts originating from the tendon sheath, careful attention should be paid to locate satellite masses to avoid recurrence.

Value of computed tomography arthrography with delayed acquisitions in the work-up of ganglion cysts of the tarsal tunnel: report of three cases

Ganglion cysts are a common cause of tarsal tunnel syndrome. As in other locations, these cysts are believed to communicate with neighboring joints. The positive diagnosis and preoperative work-up of these cysts require identification and location of the cyst pedicles so that they may be excised and the risk of recurrence decreased. This can be challenging with ultrasonography and magnetic resonance (MR) imaging. We present three cases of symptomatic ganglion cysts of the tarsal tunnel, diagnosed by MR imaging, where computed tomography (CT) arthrography with delayed acquisitions helped to confirm the diagnosis and identify precisely the topography of the communication with the subtalar joint. These cases provide new evidence of the articular origin of ganglion cysts developing in the tarsal tunnel.

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.

The clock face guide to peroneal intraneural ganglia: critical "times" and sites for accurate diagnosis

OBJECTIVE

The aim of this study is to exploit the normal nature of peroneal nerve anatomy to identify constant magnetic resonance imaging (MRI) patterns in peroneal intraneural ganglia.

DESIGN

This study is designed as a retrospective clinical study.

MATERIALS AND METHODS

MR images of 25 patients with peroneal intraneural ganglia were analyzed and were compared to those of 25 patients with extraneural ganglia and 25 individuals with normal knees. All specimens were interpreted as left-sided. Using conventional axial images, the position of the common peroneal nerve and either intraneural or extraneural cyst was determined relative to the proximal fibula and the superior tibiofibular joint using a symbolic clock face. In all patients, the common peroneal nerve could be seen between the 4 and 5 o'clock position at the mid-portion of the fibular head. In patients with intraneural ganglia, a single axial image could reproducibly and reliably demonstrate both cyst within the common peroneal nerve at the mid-portion of the fibular head (signet ring sign) between 4 and 5 o'clock and within the articular branch at the superior tibiofibular joint connection (tail sign) between 11 and 12 o'clock; in addition, cyst within the transverse limb of the articular branch (transverse limb sign) was seen at the mid-portion of the fibular neck between the 12 and 2 o'clock positions on serial images. Extraneural ganglia typically arose from more superior joint connections with the epicenter of the cyst varying around the entire clock face without a consistent pattern. There was no significant difference between the visual and template assessment of clock face position for all three groups (intraneural, extraneural, and controls). We believe that the normal anatomic and pathologic relationships of the common peroneal nerve in the vicinity of the fibular neck/head region can be established readily and reliably on single axial images. This technique can provide radiologists and surgeons with rapid and reproducible information for diagnosis and treatment planning.

CONCLUSIONS

By using conventional bony anatomy as reference points (namely fibular neck and mid-portion of fibular head), standard axial images can be used to interpret key features of peroneal intraneural ganglia and to establish their accurate diagnosis (rather than extraneural ganglia) and pathogenesis from an articular origin (rather than from de novo formation), a fact that has important therapeutic implications. Because of the relative rarity of peroneal intraneural cysts and physicians' (radiologists and surgeons) inexperience with them and the complexity of their findings, they are frequently misdiagnosed and joint communications are not appreciated preoperatively or intraoperatively. As a result, outcomes are suboptimal and recurrences are common.

Peroneal intraneural ganglia. Part I. Techniques for successful diagnosis and treatment

The common peroneal nerve is the peripheral nerve most often affected by intraneural ganglion cysts. Although the pathogenesis of these cysts has been the subject of controversy in the literature, it is becoming increasingly evident that they are of articular origin. Recent recognition of this fact has proven to be significant in reducing recurrences and improving treatment outcomes for patients. The authors present a stepwise method of assessing and treating peroneal intraneural ganglion cysts.

Coexisting secondary intraneural and vascular adventitial ganglion cysts of joint origin: a causal rather than a coincidental relationship supporting an articular theory

OBJECTIVE

To introduce the clinical entity of an intraneural ganglion cyst coexisting with a vascular adventitial cyst arising from the same joint.

DESIGN

Retrospective review.

PATIENTS

Two patients presented with predominantly deep peroneal neuropathy due to complex superior tibiofibular joint-related cysts. In addition to having peroneal intraneural ganglion cysts, these patients had vascular adventitial cysts: one involving a capsular arterial branch, the other a capsular vein [as well as a large, recurrent, intramuscular (extraneural) ganglion]. We then reviewed MRIs of 12 other consecutive cases of intraneural ganglia (10 peroneal and 2 tibial) arising from the superior tibiofibular joint that we treated, as well as other reported cases in the literature to determine if there were other (unrecognized) examples supporting the combination of clinical findings and radiographic patterns.

RESULTS

Retrospective analysis of MRIs in the two surgically proven cases of peroneal intraneural ganglia with vascular adventitial cyst extension showed a common imaging pattern that we have termed "the wishbone sign," consisting of the connection of the ascending limb of the peroneal intraneural ganglion and the longitudinal limb of the vascular adventitial cyst in the axial plane. Our review suggests that vascular adventitial cyst extension occurs in a large proportion of cases of peroneal intraneural ganglia. A similar growth pattern was noted in a case of a tibial intraneural ganglion.

CONCLUSIONS

The combination of intraneural and vascular adventitial cysts is understandable given our knowledge of normal and pathologic anatomy of para-articular cysts. The combination of intraneural ganglia and vascular adventitial cysts broadens the spectrum of clinical presentations of these cysts and suggests that cysts and their content can dissect from a joint along neurovascular bundles. These cases provide important evidence to support the articular theory for the pathogenesis of not only neural but vascular adventitial cysts as well.