Local compression of the sciatic nerve by a vascular malformation as a rare cause of sciatica: A case report and review of literature

Background

Sciatica is typically caused by disc herniations or spinal stenosis. Extraspinal compression of the sciatic nerve is less frequent.

Case Description

We report a rare case of sciatica with compression of the sciatic nerve by a low-flow vascular malformation in a 24-year-old female patient. The special feature of this case was sciatica along the S1 dermatome, which only occurred in the sitting position and inclination because of compression of the sciatic nerve between the vascular malformation and the lesser trochanter. Spinal imaging showed no abnormal findings. Surgery was performed interdisciplinary and included neurosurgery, vascular surgery, and trauma surgery. After surgery, the patient became symptom-free.

Conclusion

Rare and extraspinal causes of local compression of the sciatic nerve should be considered, especially in cases of lacking spinal imaging correlation and untypical clinical presentation. Interdisciplinary surgical cooperation is of special value in cases of rare entities and uncommon locations.

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.

Structured magnetic resonance imaging-based characterization of the marginal vein reveals limits of the Weber-classification

Background: The marginal vein (MV) is a persisting embryonic vein located at the lateral aspect of the lower limb. The Weber-classification, which was developed on the basis of phlebography in the 1990s, is the only existing classification system for this rare disease. Aim of this study was the structured characterization of the lateral marginal vein (MV) using magnetic resonance imaging (MRI) and evaluation of the applicability of the Weber-classification. Patients and methods: Institutional Review Board approval was obtained for this retrospective, single-center study. All patients who underwent contrast-enhanced MRI (using a prospectively determined protocol) of the untreated MV were included. MV anatomy and associated findings were characterized in a structured way taking into account the criteria of the Weber-classification for MV: inflow, outflow and extension. If three criteria of the Weber-classification were fulfilled the MV was categorized as "classifiable according to Weber". The MV was categorized as "partially classifiable according to Weber", if two criteria were met and as "not classifiable according to Weber" if less than two criteria were applicable. Results: 56 imaging studies of 58 MV (7 thoracoabdominal, 51 lower extremities) were reviewed. 18/51 MV of the lower extremities were "classifiable" according to the Weber-classification. 33/51 lower extremity MV were not definitely categorized according to the Weber-classification: 19/51 MV were "partially classifiable" and 14/51 MV were "not classifiable". 30/51 MV presented with hypoplastic, 1/51 with aplastic deep venous system. 34/51 lower extremity and 6/7 thoracoabdominal MV were associated with an additional vascular malformation (VM). Conclusions: MRI is suitable for detailed anatomic characterization of the MV and reveals additional therapy relevant findings like associated VM. The Weber-classification was not applicable in most cases, reflecting its limits and the heterogeneity of this rare disease. Structured reports rather than an obsolete classification system should be preferred for MRI of the MV.

Chronic sciatic nerve compression secondary to arteriovenous malformation: case discussion and literature review

Sciatic nerve symptomatology may arise from both intra- and extra-neural pathology, at any point along descent from the sacral plexus to its bifurcation. The potential aetiology is broad, ranging from degenerative spinal disease to muscle, bony and vascular pathology. We present an extremely unusual case of position and exercise-induced nerve compression secondary to arteriovenous malformation and review the potential extraspinal causes, many of which may be ameliorated by surgical excision or decompression. We further discuss the usefulness of diagnostic imaging, specific clinical tests and histopathological tools that may aid in management.

Extra-spinal sciatica and sciatica mimics: a scoping review

Not all sciatica-like manifestations are of lumbar spine origin. Some of them are caused at points along the extra-spinal course of the sciatic nerve, making diagnosis difficult for the treating physician and delaying adequate treatment. While evaluating a patient with sciatica, straightforward diagnostic conclusions are impossible without first excluding sciatica mimics. Examples of benign extra-spinal sciatica are: piriformis syndrome, walletosis, quadratus lumborum myofascial pain syndrome, cluneal nerve disorder, and osteitis condensans ilii. In some cases, extra-spinal sciatica may have a catastrophic course when the sciatic nerve is involved in cyclical sciatica, or the piriformis muscle in piriformis pyomyositis. In addition to cases of sciatica with clear spinal or extra-spinal origin, some cases can be a product of both origins; the same could be true for pseudo-sciatica or sciatica mimics, we simply don’t know how prevalent extra-spinal sciatica is among total sciatica cases. As treatment regimens differ for spinal, extra-spinal sciatica, and sciatica-mimics, their precise diagnosis will help physicians to make a targeted treatment plan. As published works regarding extra-spinal sciatica and sciatica mimics include only a few case reports and case series, and systematic reviews addressing them are hardly feasible at this stage, a scoping review in the field can be an eye-opener for the scientific community to do larger-scale prospective research.

MR imaging of venous malformations: sciatic nerve infiltration patterns and involved muscle groups

The aim of this retrospective cross-sectional study was to provide an MRI-based examination framework of venous malformations (VMs) infiltrating the sciatic nerve and determine the frequency of nerve infiltration patterns and muscle involvement in correlation to the patients’ quality of life. Pelvic and lower limb MR images of 378 patients with vascular malformations were examined retrospectively. Pain levels and restriction of motion were evaluated with a questionnaire. Cross-sectional areas of affected nerves were compared at standardized anatomical landmarks. Intraneural infiltration patterns and involvement of muscles surrounding the sciatic nerve were documented. Sciatic nerve infiltration occurred in 23/299 patients (7.7%) with VM. In all cases (23/23; 100%), gluteal or hamstring muscles surrounding the nerve were affected by the VM. Infiltrated nerves were enlarged and showed signal alterations (T2-hyperintensity) compared to the unaffected side. Enlarged nerve cross-sectional areas were associated with elevated pain levels. Three nerve infiltration patterns were observed: subepineurial (12/23; 52.2%), subparaneurial (6/23; 26.1%) and combined (5/23; 21.7%) infiltration. This study provides a clinically relevant assessment for sciatic nerve infiltration patterns and muscle involvement of VMs, while suggesting that VMs in gluteal and hamstring muscles require closer investigation of the sciatic nerve by the radiologist.

Sciatic neuropathy caused by a pressure ulcer: A case report

RATIONALE

Sciatic neuropathy has various causes; however, cases in which a pressure ulcer led to sciatic neuropathy have not been reported to date.

PATIENT CONCERNS

A 33-year-old woman with no pre-existing mobility problems visited our department with the chief complaint of an extensive pressure ulcer and necrosis in her right buttock. She had a medical history of being bedridden for 2 days while in a coma due to a drug overdose 2 months previously. Physical examination revealed loss of sensation and foot drop in the right foot.

DIAGNOSIS

Physical examination, magnetic resonance imaging, and nerve conduction studies were conducted; the patient was diagnosed with a common peroneal branch injury of the right sciatic nerve.

INTERVENTIONS

The necrotic tissue was debrided and sciatic nerve decompression was performed, followed by frequent dressing changes. In addition, psychiatric treatment and physical therapy were performed simultaneously.

OUTCOMES

The pressure ulcer decreased in size and healed to some extent with granulation tissue. However, gait disorders, accompanied by symptoms of sciatic neuropathy, continued. The patient was transferred to the department of gastroenterology for the treatment of toxic hepatitis, which occurred during her inpatient treatment.

LESSONS

Physicians should be aware that sciatic neuropathy may occur during the treatment of patients with a pressure ulcer who exhibit no symptoms of paraplegia or quadriplegia. To prevent neuropathy, aggressive treatment of the pressure ulcer is necessary.

MR imaging features of presumed retroclavicular and periscapular intermuscular vascular plexi - An observational, anatomic study

OBJECTIVE

To describe MR imaging features of presumed vascular plexi in the periscapular (PSC) and retroclavicular (RC) locations.

MATERIALS/METHODS

443 consecutive MR studies performed as "brachial plexus" protocol (axialT1-W and sagittal STIR) were reviewed for presence, size and characteristics of PSC and RC plexi.

RESULTS

Presumed PSC and RC vascular plexi were present in 10%. Both plexi more commonly occurred on the left side. Percutaneous biopsy (n = 1) yielded no vascular neoplasm.

CONCLUSION

RC and PSC vascular plexi are commonly encountered on routine brachial plexus MR imaging and may represent variant vascular networks, as they are frequently found on the contralateral asymptomatic side.

Siatic nerve: beyond the sacral foramen

Sciatica may result from pathologies affecting the nerve both in its intraspinal and extraspinal course. In daily routine, the vast majority of cases are caused by herniation of the lumbar discs compressing the neural roots. Extraspinal causes of sciatic pain are usually underestimated and the imaging study may be completed after reporting the lumbar MRIs. However, early diagnosis of the exact etiology of sciatica is paramount for both relieving the symptoms and preventing any additional neurologic injury. In this pictorial assay, some relatively rare causes of sciatic neuralgia along the route of the sciatic nerve after leaving the sacral foramen will be displayed.

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.

Spinal epidural venous angioma: a case report and review of the literature

BACKGROUND

As a vascular malformation, venous angioma in the spinal cord is extremely rare. To our knowledge, there are only five case reports in the literature, and it has not been previously reported in the pediatric age group.

CASE REPORT

In this paper, we report on a 3-year-old patient who presented with progressive weakness in his left upper limb. Spinal magnetic resonance imaging (MRI) revealed an epidural cystic mass at the C6-T2 level. The lesion was diagnosed as venous angioma after total removal with laminectomy. Postoperatively, the patient remained symptom free, and no tumor recurrence was confirmed based on MRI at the time of the 18-month follow-up. The clinical, radiological, surgical, and pathological features of this abnormality are discussed, and all six reported cases were reviewed.

CONCLUSION

Venous angiomas should be included in the differential diagnosis of spinal cystic lesions in children. A definitive diagnosis is difficult based on MRI alone. This rare lesion is amenable to surgery, and gross total removal (GTR) is usually achievable due to a well-demarcated dissection plane. A good clinical outcome after GTR can be expected.

Clinical and electrodiagnostic features of sciatic neuropathies

Sciatic neuropathy is the second most common neuropathy of the lower extremity and a common cause of foot drop. This article reviews the anatomy, clinical features, pathophysiology, and electrodiagnostic assessment of sciatic neuropathies. There are multiple potential sites of pathology, determined in part by the mechanism of insult, including trauma, compression, masses, inflammation, and vascular lesions. Diagnosis is augmented by careful electrodiagnostic studies and imaging to help distinguish sciatic neuropathy from other sources of pathology. Electrodiagnostic studies may also help in assessing for early recovery and in determining prognosis.

Klippel-Trenaunay syndrome: a rare cause of disabling pain after a femoral fracture

Klippel-Trenaunay syndrome (KTS) is characterized by a cutaneous vascular nevus of the involved extremity, as well as bone and soft tissue hypertrophy of the extremity and venous malformations. We present the case of a 52-year-old man with a femoral fracture and a history of haemangiomas, limb bone hypertrophy and varicosity. The patient was finally diagnosed with KTS and treated in mini-invasive surgery by endomedullary fracture nailing in general anaesthesia. Clinical management was particularly demanding, not only because of the need to monitor the risk of haemorrhage and thrombosis but also because of the onset of a rare picture of neuropathic pain with hyperalgesia and allodynia, never previously reported in patients affected by KTS, that required the administration of major opioid drugs. According to our knowledge, this is the second case of KTS managed for femoral fracture. Unlike the previous report in literature, in this case a severe disabling neuropathic pain complicated the clinical management.

3-T high-resolution MR neurography of sciatic neuropathy

OBJECTIVE

The sciatic nerve may normally exhibit mild T2 hyperintensity in MR neurography (MRN) images, rendering assessment of sciatic neuropathy difficult. The purpose of this case-control study was to evaluate whether a quantitative and qualitative analysis of the sciatic nerves and regional skeletal muscles increases the accuracy of MRN in detecting sciatic neuropathy.

MATERIALS AND METHODS

We retrospectively reviewed the MRN studies of the pelvis and thighs of 34 subjects (12 men and 22 women; mean [± SD] age, 50 ± 15 years), of which 17 had a final diagnosis of sciatic neuropathy according to electrodiagnostic or surgical confirmation, and 17 had no evidence of sciatic neuropathy and served as control subjects. On each side, the sciatic nerves were evaluated for signal intensity (SI), size, course, and fascicular shape, whereas the regional skeletal muscles were evaluated for edema, fatty replacement, and atrophy. In addition, the nerve-to-vessel SI ratio was registered for each side at the same time and 8 months later.

RESULTS

The sciatic nerves of the abnormal sides exhibited higher nerve-to-vessel SI ratios and higher incidences of T2 hyperintensity, enlargement, and abnormal fascicular shape compared to the nerves of the normal sides. The regional muscles of the abnormal sides demonstrated a higher grade of fatty infiltration and higher frequencies of edema and atrophy. A cutoff value of nerve-to-vessel SI ratio of 0.89 exhibited high sensitivity and specificity in predicting sciatic neuropathy. Calculation of the nerve-to-vessel SI ratio demonstrated excellent inter- and intraobserver reliability.

CONCLUSION

Both qualitative and quantitative criteria should be used to suggest the MRN diagnosis of sciatic neuropathy.