Nicholas M. Desy

Sequential tibial and peroneal intraneural ganglia arising from the superior tibiofibular joint.

We present a patient who developed a peroneal intraneural ganglion and an adventitial cyst following the incomplete treatment of a tibial intraneural ganglion. These separate cysts all originated from the superior tibiofibular joint and dissected along their respective articular branches. A logical mechanistic explanation for these coexisting cysts is provided, which highlights the shared pathogenesis—its joint-related nature—rather than a multifocal de novo process. These observations would not only be consistent with, but would extend previous evidence in support of, the unifying articular (synovial) theory.

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

ObjectiveTo introduce the clinical entity of an intraneural ganglion cyst coexisting with a vascular adventitial cyst arising from the same joint.DesignRetrospective review.PatientsTwo 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.ResultsRetrospective 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.ConclusionsThe 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.

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 worlds 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 worlds literature and the MR images further supports the articular (synovial) theory and provides baseline data for future investigators.

Evaluation of ganglion cysts using vastly undersampled isotropic projection reconstruction (VIPR)

For some atypical para‐articular ganglia, the presence of a joint connection is highly controversial. The proper preoperative diagnosis and identification of this joint connection for ganglion cysts is important for patient treatment and outcome. MRI is the imaging modality of choice when evaluating such lesions, but the detection of subtle joint connections remains difficult with conventional MR protocols. We investigated the utility of a steady‐state free‐precession acquisition with isotropic high resolution using the vastly undersampled isotropic projection reconstruction (VIPR) pulse sequence to determine if joint connections for ganglion cysts could be seen more effectively, using the knee region as a model. We evaluated four patients: two with peroneal intraneural ganglion cysts, one with adventitial cystic disease of the popliteal artery, and one patient with a more typical extraneural (intramuscular) cyst. Both conventional MR and VIPR techniques were used. In our clinical experience, we found VIPR to be superior to conventional MR techniques in detecting and depicting joint connections in typical and atypical ganglion cysts around the knee. J. Magn. Reson. Imaging 2007.

The Unifying Articular (Synovial) Origin for Intraneural Ganglion Cysts: Moving Beyond a Theory

To the Editor: We read with interest the recent paper of Dr. Naam and colleagues describing their series of patients with intraneural ganglia in the hand and wrist region. We graciously acknowledge their strong endorsement of the articular theory that our group introduced for intraneural ganglia. Several years ago, we learned of Dr. Naam’s large experience with these cysts (Naam NH, presented at the 69th Annual Meeting of the American Society for Surgery of the Hand, 2014) and asked to review any apparent outlier that he had seen since he had become aware of our theory. He provided us with the full set of magnetic resonance imaging (MRI) studies from 2013 of the only case that he had treated when a joint connection was not identified on the preoperative imaging or by him at surgery and that had MRI studies available. The case was a 65-year-old woman with an intraneural cyst of the dorsal branch of the digital nerve to the radial aspect of the ring finger. This was confirmed as the patient included in the cohort of patients treated by Dr. Naam and illustrated in Figure 3 in The Journal of

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. Clin. Anat. 28:1058–1069, 2015.

Survivorship of Metaphyseal Sleeves in Revision Total Knee Arthroplasty

BACKGROUND Metaphyseal fixation has promising early results in providing component stability and fixation in revision total knee arthroplasty (TKA). However, there are limited studies on midterm results of metaphyseal sleeves. We analyzed complications, rerevisions, and survivorship free of revision for aseptic loosening of metaphyseal sleeves in revision TKA. METHODS Two hundred eighty patients with 393 metaphyseal sleeves (144 femoral, 249 tibial) implanted during revision TKA from 2006-2014 were reviewed. Sleeves were most commonly cemented (55% femoral, 72% tibial). Mean follow-up was 3 years, mean age was 66 years, and mean body mass index was 34 kg/m2. Indications for revision TKA included 2-stage reimplantation for deep infection (37%), aseptic loosening of the tibia (14%), femur (12%), or both components (9%), and instability (14%). RESULTS There was a 12% rate of perioperative complications, most commonly intraoperative fracture (6.5%). Eight sleeves (2.5%) required removal: 6 (2%) during component resection for deep infection (all were well-fixed at removal) as well as 1 (0.8%) femoral sleeve and 1 (0.8%) tibial sleeve for aseptic loosening. Five-year survivorship free of revision for aseptic loosening was 96% and 99.5% for femoral and tibial sleeves, respectively. Level of constraint, bone loss, sleeve and/or stem fixation, and revision indication did not significantly affect outcomes. CONCLUSION Metaphyseal sleeve fixation to enhance component stability during revision TKA has a 5-year survivorship free of revision for aseptic loosening of 96% and 99.5% in femoral and tibial sleeves, respectively. Both cemented and cementless sleeve fixation provides reliable durability at intermediate follow-up.

The mechanism underlying combined medial and lateral plantar and tibial intraneural ganglia in the tarsal tunnel

Intraneural ganglion cysts in the tarsal tunnel are rare. We present a patient who had an intraneural ganglion cyst involving the medial and lateral plantar and distal tibial nerves. Magnetic resonance imaging revealed evidence to support the joint-related (i.e., subtalar) origin of the cyst. Careful reinterpretation of the imaging supported a phasic mechanism (i.e., cross-over) to explain the interrelated pathogenesis of the intraneural cyst within the three nerves. This mechanism is analogous to that described for the prototypes—the peroneal, tibial and sciatic nerves in the knee region—and can be generalized to other nerves in the foot and ankle region. We believe that understanding the pathogenesis sheds light on the effective treatment.

Ganglion cysts and nerves

Ganglion cysts are benign, contained collections of mucin, typically related to neighboring synovial joints that may affect nerve indirectly by extrinsic compression or directly by intrinsic compression. A unifying synovial (articular) theory explains extraneural and intraneural ganglia in terms of their dissection through capsular defects separate from or within articular branch connections. Depending on the site of the capsular defect, these cysts tend to form along paths of least resistance and take shape by pressure fluxes. Identification of the non-neural or neural joint connection (“pedicle”) and its surgical removal is important to decrease recurrence and to improve patient outcomes. New imaging techniques can help the radiologist and treating surgeon detect the pedicle, obtain a preoperative diagnosis and direct the nature of the intervention. This review summarizes recent advances in the pathogenesis, evaluation, and management of patients with ganglia affecting nerve.

Subparaneurial ganglion cysts of the fibular and tibial nerves: A new variant of intraneural ganglion cysts

Over the last decade, the mechanism of formation of intraneural ganglion cysts has been established through a meticulous review of clinical findings and correlation with patterns produced on magnetic resonance imaging (MRI). Pathognomonic imaging patterns distinguish these rare lesions from the more common extraneural variants in almost all cases. In this report, we present a new pattern of cyst occurrence in the subparaneurial compartment of the nerve and provide potential anatomic explanations for its pathogenesis. Using an anatomic framework of connective tissue compartments of the nerve, we reviewed 63 (56 fibular and seven tibial) intraneural ganglion cysts in the knee region evaluated at our institution and all reports with MRI in the worlds literature for evidence of cyst occurrence in the subparaneurial compartment. We identified six cases (five in the common fibular nerve and one in the tibial nerve) at our institution that had MR evidence of cyst in the subparaneurial compartment with a new complex lobulated pattern. All cases had articular branch connections to the superior tibiofibular joint, which at operation were resected along with the joints. Follow‐up revealed complete recovery in all instances and no clinical or radiological signs of recurrence. Three cases out of 80 in the literature exhibited the new complex lobulated MRI pattern. We present a new pattern of intraneural ganglion cyst occurrence in a potential space that surrounds peripheral nerves‐ the subparaneurial compartment. We believe that the unifying articular theory applies to the pathogenesis and management of these rare variants. Clin. Anat. 29:530–537, 2016.