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J Neurosurg Case Lessons
J Neurosurg Case Lessons
J Neurosurg Case Lessons
Journal of Neurosurgery: Case Lessons
2694-1902
American Association of Neurological Surgeons

39186820
10.3171/CASE23652
CASE23652
AnatomyAnatomyPainPainPeripheral-NervePeripheral NerveSpineSpineLumbarLumbarTechniqueTechniqueDiagnostic-TechniqueDiagnostic TechniqueCase Lesson
Sciatica secondary to deep venous thrombosis of the persistent sciatic vein: the first case in the literature. Illustrative case
Orlando Vittorio MD 1*
Benenati Massimo MD 2*
Galieri Gianluca MD 1
Della Pepa Giuseppe M PhD 13
La Rocca Giuseppe PhD 13
1 Department of Neuroscience, Catholic University of the Sacred Heart, Rome, Italy
2 Department of Radiology and Neuroradiology, IRCCS A. Gemelli University Polyclinic Foundation, Rome, Italy
3 Department of Neurosurgery, IRCCS A. Gemelli University Polyclinic Foundation, Rome, Italy
Correspondence Vittorio Orlando: Catholic University of the Sacred Heart, Rome, Italy. orlandovittorio.md@gmail.com.
INCLUDE WHEN CITING Published August 26, 2024; DOI: 10.3171/CASE23652.

Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

* V.O. and M.B. contributed equally to this work.

26 8 2024
26 8 2024
8 9 CASE2365210 11 2023
05 1 2024
© 2024 the authors
2024
the authors
https://creativecommons.org/licenses/by-nc-nd/4.0/ CC BY-NC-ND 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

BACKGROUND

Sciatica usually results from lumbar nerve compression due to factors like disc herniations or lumbar canal stenosis. Despite its common causes, sciatic pain in a 52-year-old man following a coronavirus disease 2019 infection highlighted the importance of considering less common factors. Initially, minor disc protrusions were suspected as the cause of the symptoms, leading to the offer of surgery at another facility. The patient sought a second opinion, and our evaluation revealed a unique finding.

OBSERVATIONS

Pelvic magnetic resonance imaging uncovered varicose structures displacing the left sciatic nerve. Subsequent pelvic computed tomography angiography identified a remarkable finding—the lack of opacification in a left persistent sciatic vein ascending toward a left internal iliac vein, originating from a common internal iliac venous trunk—confirming a suspicion for deep venous thrombosis. These findings represented not 1, but 2, extremely rare and distinct variants in the venous anatomy. The authors promptly initiated anticoagulant therapy and tailored pain management strategies, observing progressive thrombosis resolution on follow-up imaging.

LESSONS

This report highlights the need for comprehensive diagnostics when symptoms and imaging differ. Misdiagnosis could lead to unnecessary surgeries and potential risks for the patient.

https://thejns.org/doi/10.3171/CASE23652

sciatica
deep venous thrombosis
disc herniation
DVT
ABBREVIATIONS

COVID-19 = coronavirus disease 2019
CTA = computed tomography angiography
DVT = deep venous thrombosis
EMG = electromyography
MRA = magnetic resonance angiography
MRI = magnetic resonance imaging
PSV = persistent sciatic vein.
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pmcThis report describes the unexpected findings in a 52-year-old patient who developed sciatic pain shortly after a coronavirus disease 2019 (COVID-19) infection. Initial diagnostic efforts pointed toward some minor disc protrusions as a possible cause of the symptoms, potentially warranting surgical intervention. However, an in-depth evaluation uncovered a different cause of the sciatic pain: deep venous thrombosis (DVT) within the left common iliac vein and a left persistent sciatic vein (PSV) with compression of the left sciatic nerve. This case emphasizes the importance of comprehensive diagnostics in complex scenarios, even in common conditions like sciatic pain when common causes are not fully convincing, and provides insights for healthcare providers encountering similar challenges.

Illustrative Case

A 52-year-old patient with no significant medical history presented with the subacute onset of low-back pain and left S1 dermatomal radiating sciatica, approximately 2 weeks after contracting a COVID-19 infection. The symptoms persisted and were only minimally responsive to pharmacological therapy, prompting the patient to undergo lumbosacral magnetic resonance imaging (MRI) a month later, which revealed multiple minor disc protrusions, most notably at the L3–4 level, resulting in initial bilateral foraminal stenosis predominantly on the left side, although inconsistent with the S1 symptomatology (Fig. 1). Electromyography (EMG) showed signs of peripheral neurogenic distress at the S1 level (Fig. 2). Subsequently, the low-back pain regressed, but the sciatic S1 symptoms acutely worsened, mainly in the gluteal region. The patient developed functional impairment with minimal response to steroid and anti-inflammatory therapy. Neurological examination showed a positive Lasègue sign and S1 dysesthesia on the left leg. FIG. 1. Sagittal T2-weighted MRI (A) showing mild L3–4 disc bulging. Axial T2-weighted MRI at the L4–5 (B) and L5–S1 (C) levels, confirming the absence of significant radicular compression.

FIG. 2. EMG tracings of the left gastrocnemius show reduced recruitment of motor units.

Upon evaluation at another center, surgical treatment with an L3–4 discectomy and fusion of the same level was recommended. Seeking a second opinion, a month later, the patient underwent new lumbosacral MRI, which was essentially consistent with the previous study. Given the clinical picture and inconclusive radiological findings regarding the etiology of the symptoms, comprehensive MRI of the entire spine and pelvis was performed. It revealed varicose structures along the posterior aspect of the left sciatic nerve, extending from the sacrospinous ligament downstream, with signs of anterior displacement of the nerve (Fig. 3A and B). These findings were confirmed by magnetic resonance angiography (MRA) and computed tomography angiography (CTA), which showed a lack of contrast opacification in the venous lumen of the left internal iliac vein, originating from a left common internal iliac venous trunk and extending downward to a PSV (Fig. 3C–F). This radiological picture was compatible with a recent DVT. FIG. 3. A: Axial T2-weighted short tau inversion recovery (STIR) image showing abnormal signal in the left sciatic area, suggestive of venous ectasia. B: Coronal STIR image shows an abnormal signal in the left sciatic region. C: Coronal maximum intensity projection (MIP) CTA shows venous ectasia with a filling defect in the internal iliac vein common trunk and left internal iliac vein. D: Axial CTA shows venous ectasia with a filling defect in the internal iliac vein common trunk. E: Axial CTA shows venous ectasia with a filling defect in the left internal iliac vein. F: Axial CTA shows venous ectasia with a filling defect in the left sciatic region. Green outlines indicate ectasia.

The patient was then sent to the emergency department, where blood tests revealed elevated D-dimer levels; a contrast-enhanced chest computed tomography scan was negative for pulmonary embolism. Anticoagulant therapy with enoxaparin was initiated and was later replaced with fondaparinux. The painful symptoms temporarily regressed only to reappear about a week later, along with the development of distal left lower-limb edema. The patient was admitted to our department for diagnostic assessments; blood tests for thrombophilia screening were negative, and venous Doppler ultrasonography of the lower limbs showed no signs of DVT in the examined areas. Painful symptoms were effectively managed with pregabalin and tapentadol, and edema was treated with physical therapy. Subsequent MRA and CTA scanning of the pelvic girdle showed partial recanalization of the vascular lumen. Therefore, the patient was discharged with continued anticoagulant therapy.

The patient fully recovered from the sciatic symptoms a few days after home discharge. Follow-up MRI (Fig. 4A and B) and CTA (Fig. 4C–F), conducted 3 and 6 months later, demonstrated complete resolution of the DVT and a reduction in the caliber of the venous vessels, despite the persistence of some residual dilation in the left PSV. FIG. 4. Follow-up coronal (A) and axial (B) STIR images show normal signal intensity in the left sciatic area due to resolution of the thrombus. Follow-up coronal MIP CTA (C) shows resolution of the thrombus in the internal iliac vein common trunk and left internal iliac vein. Axial CTA (D) shows resolution of the thrombus in the internal iliac vein common trunk. Axial CTA (E) shows resolution of the left internal iliac vein thrombus. Axial CTA (F) shows resolution of the left thrombus with persistent venous vessels of a larger caliber than the right ones.

Patient Informed Consent

The necessary patient informed consent was obtained in this study.

Discussion

Sciatica is a debilitating and often excruciating condition that affects millions of individuals worldwide and is characterized by sharp, radiating pain along the territory innervated by the sciatic nerve. In most cases, this condition is caused by compressive phenomena on the lumbar nerve roots due to disc herniations or lumbar canal stenosis. However, given its high prevalence in the population, it is mandatory to rule out less common causes in the differential diagnosis when the etiology of symptoms is not clear.

To the best of our knowledge, this is the first reported case in which a pure left S1 sciatica was caused by DVT starting from a left PSV and extending to the internal and common iliac veins, with direct compression of the sciatic nerve in a patient without comorbidities. A similar case of sciatic neuropathy was described in a patient hospitalized in the intensive care unit with extensive DVT due to stasis caused by uroseptic shock. However, in that case report, the clinical manifestation was diffuse lower-limb weakness and paresthesia in the left leg.1

An indirect correlation between sciatica and DVT has been described in cases of thrombosis of epidural venous plexuses, some of which were associated with venous return defects due to anomalies or obstruction of the inferior vena cava or portal vein thrombosis, leading to direct compression of the lumbar nerve roots.2–6

Observations

The uniqueness of this case lies in the presence of 2 rare anatomical variants: 1) a left PSV and 2) 2 internal iliac veins originating from a single venous trunk converging into the left common iliac vein. We hypothesize that these unique anatomical variations of the venous anatomy may have contributed to the development of DVT in this region by inducing flow anomalies.

A PSV is a rare congenital vascular anomaly linked to varicose veins, skin hemangiomas, and tissue hypertrophy, often associated with Klippel-Trenaunay syndrome.7 It represents the primary embryologic vascular outflow of the lower extremity during fetal development, regressing around 10–12 weeks. It originates from posterior muscle tributaries, runs with the sciatic artery, receives posterior gluteal vessels, and enters the pelvis via the subpyramidal portion where it follows the sciatic nerve and drains into the internal iliac, inferior gluteal, and deep femoral veins. Anatomically, 3 variations exist: complete, upper, and lower (Fig. 5).8 Our patient's PSV matches the upper type, connecting to the internal iliac venous system.9, 10 FIG. 5. Complete (A), upper (B), and lower (C) PSV. Cherry et al., 1996.8

The internal iliac vein variant, already described in the literature and identified in cadaveric studies, could have played a role in the proximal extension of the DVT in the absence of other congenital thrombophilia risk factors.11

Last but not least, the recent COVID-19 infection could be considered another relevant factor because of its increased risk of DVT development.12

In the case under discussion, we hypothesize that the pain originated from the direct mechanical compression of the thrombosed PSV on the sciatic nerve. Given the suspected symptom etiology and the absence of structural nerve entrapment, the sole viable treatment option appeared to be medical therapy, precluding any potential role for surgical decompression of the nerve.

Lessons

The clinical importance of this case is the necessity of an appropriate differential diagnosis if there is discordance between symptoms and radiological findings. This report underscores the importance of considering all possible etiological hypotheses in situations where traditional radiological and instrumental investigations in patients with sciatica do not provide clear answers. Misdiagnosis can lead to unnecessary surgical interventions, posing substantial risks to patients.

When discordance exists, other uncommon causes of sciatica should be explored, including DVT, if laboratory examinations reveal a potential suspect. Moreover, hypothetical spinal surgery would have exposed the patient to a significantly elevated risk of thromboembolism. The multidisciplinary assessment, diagnostic challenges, pharmacological therapy, and outcomes of this unique case provide valuable insights for healthcare providers in the management of similar clinical scenarios.

Disclosures

The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

Author Contributions

Conception and design: Orlando, Benenati, Della Pepa, La Rocca. Acquisition of data: Orlando, Benenati, Galieri, La Rocca. Analysis and interpretation of data: Orlando, Benenati, Galieri. Drafting the article: Orlando. Critically revising the article: Orlando, Della Pepa, La Rocca. Reviewed submitted version of manuscript: Orlando, Della Pepa. Approved the final version of the manuscript on behalf of all authors: Orlando. Administrative/technical/material support: Benenati. Study supervision: Della Pepa, La Rocca.

Correspondence

Vittorio Orlando: Catholic University of the Sacred Heart, Rome, Italy. orlandovittorio.md@gmail.com.
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