The diagnostic value of ultrasonography in evaluation of the intraneural vascular anomalies of peripheral nerves

BACKGROUND

The imaging diagnosis of intraneural vascular anomalies of peripheral nerves mostly depended on magnetic resonance imaging (MRI), whereas high-frequency ultrasonography evaluation of intraneural vascular anomalies has been seldom done.

PURPOSE

To evaluate the diagnostic value of ultrasonography in the diagnosis of intraneural vascular anomalies of peripheral nerves.

MATERIAL AND METHODS

A total of 69 consecutive patients seen at Shandong Provincial Hospital Affiliated to Shandong First Medical University between February 2013 and June 2022, each with a clinical suspicion of intraneural vascular anomaly, were included. The ultrasonographic images of intraneural vascular anomalies of peripheral nerves were analyzed and the ultrasonographic features were summarized. These data were compared with MRI, which served as the gold standard for the diagnosis of intraneural vascular anomalies. The kappa statistic was adopted to determine the level of agreement. The sensitivity, specificity, positive and negative predictive values, accuracy, and Youden index of high-frequency ultrasonography as a diagnostic tool were assessed.

RESULTS

Ultrasonography findings were positive in 20 of 69 patients with a clinical suspicion of intraneural vascular anomaly. The diagnosis was confirmed by MRI in 21 patients. There was one false-positive result and two false-negative results by ultrasonography. The κ value was 0.896. The sensitivity, specificity, positive and negative predictive values, accuracy, and Youden index of ultrasonography were 90.5%, 97.9%, 95%, 95.9%, 95.7%, and 0.884, respectively.

CONCLUSION

Ultrasonography could be an accurate, reliable, and convenient imaging tool for the diagnosis of intraneural vascular anomalies of peripheral nerves.

Comparison of speed of onset and analgesic effect of 2% mepivacaine hydrochloride deposited within or outside the neurovascular bundle at the level of the proximal sesamoid bones in horses with naturally occurring forefoot-related lameness

OBJECTIVE

To compare the speed of onset and analgesic effect of mepivacaine deposited within or immediately outside the neurovascular bundle at the base of the proximal sesamoid bones in horses.

ANIMALS

6 horses with naturally occurring forefoot-related lameness.

PROCEDURES

In a crossover study design, horses were randomly assigned to receive 1 of 2 treatments first, with the second treatment administered 3 to 7 days later. Trotting gait was analyzed with an inertial sensor-based motion analysis system immediately before treatment to determine degree of lameness. Afterward, ultrasound guidance was used to inject 2% mepivacaine hydrochloride around the palmar digital nerves of the affected forelimb at the level of the base of the proximal sesamoid bones either within the subcircumneural space or outside the circumneural sheath. After injection, gait was reevaluated at 5-minute intervals for 45 minutes.

RESULTS

Mepivacaine deposition outside the circumneural sheath did not resolve lameness in any horse; for 3 horses, the mean time to 70% reduction of initial vertical head movement was 13.3 minutes, and the remaining 3 horses had no such reduction at any point. Mepivacaine deposition within the subcircumneural space resulted in a mean time to 70% reduction of initial vertical head movement of 6.7 minutes and mean time to resolution of lameness of 21.7 minutes.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that when peripheral nerves of horses lie within a sheath, local anesthetic solution should be deposited within the sheath for an effective nerve block. If local anesthetic solution is deposited outside the sheath, the nerve block may yield erroneous results.

Understanding the Pathognomonic Tumefactive Appearance of Neurolymphomatosis: A Unifying Theory of Neurolymphoma

BACKGROUND

The diagnosis of peripheral neurolymphomatosis (NL) is difficult and often delayed, because patients can have isolated, nonspecific nerve symptoms. Magnetic resonance imaging will usually show nonspecific findings of enlarged, contrast-enhancing nerves. We aimed to elucidate the mechanism behind an imaging finding we believe is pathognomonic of NL and likely of other hematologic diseases with peripheral nerve involvement.

METHODS

We reviewed the imaging studies of a previously reported cohort of patients, in addition to those from more recent patients, all with tumefactive NL, in which enlarged nerve bundles were surrounded by tumor. We reviewed the demographic data, clinical data (e.g., primary or secondary disease, biopsy-proven diagnosis), and imaging findings (e.g., tumefactive appearance, primary involved nerve, location of epicenter of tumefactive appearance, vascular involvement).

RESULTS

All cases showed a maximum tumefactive appearance at branch or junction points, with a gradual decrease of this appearance moving proximally and distally from the epicenter in a "crescendo-decrescendo" pattern. We have described this as a phasic mechanism with 3 phases: malignant cells fill the intraneural space; extrude at a weak spot of the nerve, which often occurs at a branch or junction point; and then expand and fill the subparaneurial space, creating the grossly tumefactive appearance with proximal and distal spread.

CONCLUSIONS

We have presented a novel, unifying theory explaining the pathognomonic tumefactive appearance of NL. Our theory offers the first rational explanation for the radiological appearance of NL with peripheral nerve involvement. We believe that with earlier recognition of NL on imaging studies, patients will be able to receive an earlier diagnosis and undergo earlier treatment.

Circumferential Adipose Lesion of the Sciatic Nerve

BACKGROUND

Adipose lesions of nerve are generally distinguished as either extraneural or intraneural lipomas or, alternatively, lipomatosis of nerve. We present a patient with an unusual circumferential lipoma that completely encircles the right sciatic nerve and discuss a possible pathogenesis.

CASE DESCRIPTION

A 44-year-old woman presented with progressive symptoms and signs of sciatic neuropathy for 1 year. Magnetic resonance imaging revealed a large lipomatous mass extending from the level of the lesser trochanter to the distal third of the femur. The sciatic nerve was completely enveloped by the lipoma in the proximal segment, partially enveloped in the mid-segment and was separate from the nerve in the distal segment. The lipoma was not covered by the epineurium. The tumor was completely resected and the patient's neurologic symptoms improved.

CONCLUSIONS

The pathogenetic mechanism of the reported circumferential lipoma of the sciatic nerve is not known. Two possible mechanisms considered included 1) envelopment by an extraneural lipoma over time and 2) occurrence of a lipoma in the paraneurial compartment (and in this case, extension into an extraneural one). Based on the available literature, lipomas that circumferentially envelop the entire nerve seem to be underrecognized and poorly understood. Analogous cases of lipomas enveloping nerves or other structures than nerves have been reported in the literature. Our reported case highlights the complexity of adipose lesions affecting nerves.

A new pattern of lipomatosis of nerve: case report

Lipomatosis of nerve (LN) is a rare disorder of peripheral nerves that produces proliferation of interfascicular adipose tissue. It may be associated with soft-tissue and bony overgrowth within the affected nerve territory. LN has been almost exclusively reported in appendicular peripheral nerves; the median nerve at the wrist and palm is among the most common locations. The authors present a new pattern of LN that shows circumferential proliferation of fat around the epineurium of the nerve. They believe that this case and the two other documented examples in the literature (also affecting cervical and thoracic spinal nerves) share the same new pattern of LN. Defining the full spectrum of adipose lesions of the nerve and establishing a cause-effect relationship with nerve-territory overgrowth disorders may offer options for future management through targeted nerve lesioning.

A radiological classification system for intraneural vascular anomalies: assessment of potential for resection with high-resolution MRI

BACKGROUND

Intraneural hemangiomas and vascular malformations are rare, with approximately 50 cases reported in the literature. They present a therapeutic challenge; surgical resection can result in damage to the nerve and lesion recurrence is common. We introduce a new framework to classify intraneural vascular anomalies in relation to the anatomic compartments of the nerve and assess amenability to surgical resection.

METHODS

We retrospectively reviewed cases of intraneural hemangiomas and vascular malformations treated at our institution between 2003 and 2013 that had high-resolution 3-T magnetic resonance imaging (MRI). A review of the literature was also performed. Our cases and reports in the literature with available MRI data were sub-categorized according to their relationship to the paraneurium and epineurium of the nerve.

RESULTS

Nine patients were identified with intraneural (subparaneurial or subepineurial) vascular lesions. Two patients had a predominantly subparaneurial involvement of the nerve, six patients had predominantly subepineurial involvement, and one patient exhibited extensive involvement in both compartments. Four patients were managed surgically and the rest conservatively. Targeted resection of two subparaneurial hemangiomas provided complete relief of symptoms and freedom from recurrence at 18 month and 24 months respectively. One patient with extensive subepineurial and extraneural vascular malformations did not appear to benefit from sub-total resection with interfascicular dissection. No surgical morbidity was noted in any of the cases.

CONCLUSIONS

We believe that the subparaneurial compartment-a potential space between the epineurium and paraneurium-provides a tissue plane within which benign vascular lesions can occur. Hemangiomas and vascular malformations are complex and can occupy different intraneural and extraneural compartments. The anatomic framework aids surgical decision-making and ensures that all components of the lesion are considered. We advocate a multimodal approach in the treatment of these rare lesions.