Ulnar nerve penetration by a volar ganglion in the Guyon canal

An intraneural ganglion cyst of the ulnar nerve at the wrist: a case report and literature review

Background

Intraneural ganglion cysts of the ulnar nerve at the wrist are rare and poorly understood. We report a case of an intraneural ganglion cyst at the level of the wrist.

Case presentation: A 48-year-old man presented with the complaints of weakness for 6 months and serious aggravation for 1 month in his right hand. After examinations, including ultrasound, the patient was diagnosed with an intraneural ganglion cyst. Intraoperatively, with exposure of the ulnar nerve, we found that the intraneural ganglion cyst was at the level of Guyon’s canal and extended approximately 6 cm proximally. Postoperatively, sensation of the fingers was normal, but atrophy of his muscles and limited straightening of his ring and little fingers were similar to those preoperatively.

Conclusions

Diagnosis of an intraneural cyst before surgery is mostly based on ultrasound and magnetic resonance imaging. Transection of the articular branch is an important measure to prevent recurrence of this cyst. If the ulnar nerve is compressed and causes symptoms, nerve decompression, including removal/aspiration of the cyst, and sometimes external neurolysis of the nerve, are necessary to relieve the symptoms and allow regeneration of the nerve. However, these should be performed without damaging the nerve fascicles.

Ultrasound-Guided Perineural Injection at Guyon's Tunnel: An Anatomic Feasibility Study

Compression of the ulnar nerve (UN) at the wrist causes neuropathy in the ulnar tunnel (UT), or Guyon's tunnel. In the absence of trauma and motor syndromes, primarily conservative treatment is considered. As in carpal tunnel syndrome, a perineural injection of corticosteroids may be beneficial. The aim of this study was to investigate the feasibility of ultrasound-guided injections at the UT. We performed ultrasound-guided injections of ink at the UN within the UT in 21 limbs from 11 non-embalmed cadavers. In all cases, we stained the perineural sheath of the superficial branch of the ulnar nerve within the UT. No ink was found inside the nerve or in adjacent structures such as blood vessels and tendons. In conclusion, perineural injection of the UN in the UT seems to be a technically feasible procedure. On the basis of these anatomic data, clinical trials are needed to prove the concept for routine use.

Deep ulnar intraneural ganglia in the palm

BACKGROUND

While extraneural ganglion cysts are common and well known, intraneural ganglia are rare and misunderstood.

MATERIALS

We describe a patient with an intraneural ganglion in an unusual location, the deep branch of the ulnar nerve in the palm. We confirmed a connection to the triquetral-hamate joint on preoperative high-resolution MRI and intraoperatively, and observed distal extension of the cyst, a variant pattern of propagation. We wondered if these intraneural cysts followed the principles of the unifying articular (synovial) theory rather than the de novo (degenerative) theory suggested by others. We reviewed patients with ulnar intraneural ganglia at the wrist for joint connections and the pattern of propagation.

RESULTS

A total of 35 cases of ulnar intraneural ganglia at the wrist were identified, of which only 10 were joint connected. In 14 cases involving the deep ulnar branch, only 4 had joint connections. We hypothesized and proved that an unrecognized joint connection would be identified in the most recently reported case of a deep ulnar intraneural cyst in which a joint connection had not been identified. Propagation patterns supported descent in all cases involving the deep branch and proximal ascent in those of the main ulnar nerve (n = 18) or the dorsal cutaneous branch (n = 3). We believe that the orientation of the articular branches may play an important role in directionality in these intraneural cysts.

CONCLUSION

Contrary to popular opinion, our analysis of the literature would suggest that intraneural ganglia at this rare site obey the common principles of the articular theory described at more common sites for intraneural ganglia.

Atypical venous glomangioma causing chronic compression of the radial sensory nerve in the forearm. A case report and review of the literature

Extrinsic chronic nerve compression induced by nonendothelium derived vascular tumors is a rare occurrence at the forearm level. We present a case of severe chronic compression of the radial sensory nerve (RSN) caused by an undiagnosed venous glomangioma. The tumor was excised with complete symptoms relief. In the presence of severe nerve compression syndromes in young age, without predisposing comorbidities, atypical extrinsic compression due to vascular tumors should be considered.