Endovascular management of persistent sciatic artery occlusion

GG Gowda, S Kr, MP Tigga 
 Department of Cardiothoracic and Vascular Surgery, JSS Medical College and Hospital, Mysore, Karnataka, India

Correspondence Address:
M P Tigga
Department of Cardiothoracic and Vascular Surgery, JSS Medical College and Hospital, Mysore, Karnataka
India

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A 64 year old man who was diabetic for the past 11 years presented with a right foot recalcitrant ulcer. Three years prior, he had undergone a right femoropopliteal vein bypass followed by amputation of the second and third toes. On examination, his right lower leg pulses were absent except for femoral. His right distal foot ulcer was covered with necrotic slough. His right ankle brachial index (ABI) was 0.3 indicating severe peripheral artery disease. His right arterial duplex ultrasound showed chronic thrombotic occlusion of distal superficial femoral artery (SFA) and popliteal artery with monophasic flows in pedal vessel. The initial contrast computerized tomography (CT) angiography reported it as distal SFA occlusion. Later, when catheter angiogram was done, it was revealed to be a persistent sciatic artery (PSA) which was occluded starting from its exit from the pelvis at greater sciatic notch reforming in the mid-thigh and continuing as popliteal artery [Figure 1], [Figure 2] and [Figure 3]a. The superficial femoral artery was of low caliber and occluded at adductor hiatus. As the patient was an elderly diabetic with scarred groin and thigh, it was decided to perform right PSA angioplasty.{Figure 1}{Figure 2}{Figure 3}

Through left common femoral artery retrograde approach, a 6Fr Balkan crossover sheath was placed into the right internal iliac artery [Figure 3]b. The right PSA was cannulated and the occlusion crossed with 0.035 Terumo wire and end-on flush catheter [Figure 3]c. Distal angiography runs were taken to confirm the catheter position in true lumen [Figure 3]c. Then the Terumo wire was exchanged with stiff wire. Serial balloon dilatations were done followed by stent placement (6 mm × 150 mm self-expanding). Stent placement was preferred as plain balloon angioplasty is known to yield suboptimal result due to significant residual stenosis. Post stent deployment, there was good contrast runoff seen across the stent distally [Figure 3]d. Post procedure, the patient's popliteal pulse was palpable and ABI increased to 0.8 (normal being 0.90 to 1.30).

Later, the patient underwent foot debridement and was put on dual antiplatelets and statins along with regular wound dressing. At 4 months follow up, the stent was patent and the wound had healed.

Sciatic artery is the principle artery of the lower limb and a branch of umbilical artery during embryonic life.[1] It degenerates and incorporates into the inferior gluteal artery forming its proximal part in the third month of gestation.[1] When it persists as seen in around 0.05% individuals, which is extremely rare, it has a strong predilection for atherosclerosis leading to occlusion or aneurysmal changes.[2],[3],[4] When completely persistent, the sciatic artery becomes tortuous and enlarged, originating from the internal iliac artery and traversing through the greater sciatic foramen in close relation to the sciatic nerve.

Clinical presentation of PSA is usually ischemic or aneurysmal disease. In the present case the diagnosis of PSA was missed initially because of its extreme rarity. The patient had undergone toe amputation 3 years back and again presented with a nonhealing ulcer. Even in the current clinical work up, the initial contrast CT angiography had reported a distal SFA occlusion. It was only on catheter angiogram that PSA with its occlusion was detected. Radiological examinations remain the mainstay for clinching the diagnosis of PSA. It is important that a radiologist is aware of this anomaly to make the diagnosis. CT, magnetic resonance (MR), or catheter angiography can be performed to make the diagnosis, but CT and MR are the preferred modalities as they are noninvasive.

It is important to be aware of PSA while dealing with vascular diseases of the lower limb, as it can save unnecessary procrastination and help in early management. In the present case PSA had gone undetected 3 years ago and the patient had to undergo amputation of his second and third toes. Arteriography is a useful tool in management of PSA, and surgical and endovascular options are available that can be individualized for each case. In our case, endovascular stenting of PSA was done which restored the limb vascularity and abated his symptoms.

Declaration of patient consent

The authors certify that appropriate patient consent was obtained.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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