Management of Aneurysmal Degeneration of Persistent Sciatic Artery: A Hybrid Approach

By Omer Ehsan¹, Jamshaid Anwar², Umair Ahmad Khan¹, Talha Kareem¹, Hassan Wyne³

Affiliations

1. Department of Vascular Surgery, Shifa International Hospital, Islamabad, Pakistan
2. Department of Interventional Radiology, Shifa International Hospital, Islamabad, Pakistan
3. Department of Urology, Multan Institute of Kidney Diseases, Multan, Pakistan

ABSTRACT
Sciatic artery aneurysms (SAAs) are incidentally found vascular anomalies. Here, the authors presented a case of a 74-year-old woman with a pulsating lump in her right buttock. CT scan revealed an aneurysm in her right persistent sciatic artery that was also the sole blood supply to the right lower limb. A successful hybrid approach, involving femoropopliteal bypass and aneurysm plugging, was implemented. This case highlights the diagnostic challenges and stresses the importance of personalised interventions. The rarity of SAAs underscores the need for enhanced awareness among clinicians and radiologists for early detection and effective management of this rare vascular condition.

Key Words: Sciatic artery aneurysm, Vascular anomalies, Embryological arterial remnant, Endovascular repair, Persistent sciatic artery.

INTRODUCTION

Sciatic artery aneurysms (SAAs) are exceptionally rare vascular anomalies occurring in ∼0.05% of the population, often discovered by chance due to their lack of symptoms.¹ These arise from the persistent sciatic artery (PSA), a developmental anomaly in which the internal iliac artery continues to supply the lower limb through PSA and is the only supply of the lower limb.² Clinically, around 48% of PSAs result in aneurysmal degeneration, causing symptoms of intermittent claudication, a pulsatile buttock mass, compressive neuropathy, and rupture.³ Diagnosis involves imaging techniques such as ultrasound or CT angiography. Previously, the mainstay of management of PSA aneurysm and/or limb ischaemia has been surgical bypass in conjunction with PSA aneurysm (PSAA) excision or ligation.⁴ Recently, hybrid treatments involving endovascular approaches have emerged as important therapeutic alternatives, owing to developments in endovascular techniques and advancements in equipment.⁵ Early diagnosis and proper intervention are essential to prevent complications and ensure the best outcomes for patients.

The authors report a case of a 74-year-old woman who presented with the complaint of pulsatile swelling in the right gluteal region, diagnosed as a PSAA.

CASE  REPORT

A 74-year-old woman visited the vascular outpatient department with a three-month complaint of a pulsatile lump in her right gluteal region. She had a history of diabetes, hypertension, and lumbar discectomy. Examination revealed a 3 × 4 cm pulsatile lump in the right gluteal region with palpable distal pulses.

The CT angiogram showed an atherosclerotic aorta, with an aneurysm in the right sciatic artery emerging from the internal iliac artery. This sciatic artery was the primary blood supply to the right lower limb. Additionally, there was tapering and diminishment of the right external iliac and common iliac arteries. However, the superficial femoral artery was patent.

The plan was to perform a Fem-Pop bypass and plugging of the aneurysm using coils and a vascular plug.

The procedure began with a right groin incision, exploring the right common femoral artery. An angiographic image of the PSAA was obtained (Figure 1). Another incision was given over the medial side of the thigh to explore the above-knee popliteal artery. After gaining control of the common femoral artery, an arteriotomy was done, and a proximal anastomosis was completed using a 6 mm ringed graft.

Another arteriotomy was performed over the popliteal artery. The interventional radiologist carried out back-door right PSA coil embolisation in the upper thigh, leaving a patent persistent artery in the thigh to allow retrograde thigh muscle arterial flow via the femoral-popliteal route (Figure 2). Following this, a front door Amplatz plug embolisation was performed to the persistent right sciatic artery just inside the pelvis, distal to pelvic branches.

Post-plugging, the graft was tunnelled subcutaneously, and a distal anastomosis with the popliteal artery above the knee was performed, while ensuring minimised limb ischaemia time. After the anastomosis, distal pulses were palpable and were confirmed with a handheld Doppler. Closure was conducted in layers. A smooth postoperative recovery ensued, leading to the patient being discharged on the third day without any complications.

Figure 1: Angiographic image of the persistent sciatic artery aneurysm.

Figure 2: Coils placed in the persistent sciatic artery aneurysm.

A follow-up CT scan performed two weeks postoperatively showed a vascular plug at the origin of the sciatic artery. The right sciatic artery appeared tortuous, with a partially thrombosed and coiled aneurysm in the right gluteal region. Minimal contrast remained within the aneurysm's lumen, mostly thrombosed. Distally, the right sciatic artery was contrast-filled during the venous phase, possibly due to retrograde filling. Mild fat stranding and reactionary changes were observed at the surgical wound site.

CT angiography performed three months post-surgery showed complete thrombosis and exclusion of the PSAA in the right gluteal region with no retrograde or antegrade flow of contrast into the aneurysm sac; the sac size had reduced from 42 mm to 38 mm preoperatively.

The patient reported resolution of all her symptoms, which were present prior to the surgery.

DISCUSSION

The PSA is the continuation of the internal iliac artery and can act as the sole dominant vessel of the lower limb. Without proper revascularisation, ligation of the PSA or plugging of the aneurysm can compromise the blood flow to the lower limb. In asymptomatic PSA, intervention might not be necessary. However, a close follow-up is mandatory.⁶ Symptomatic PSAAs need treatment to prevent potential life-threatening complications, such as rupture and thromboembolism. As PSAAs are very rare, there is, no existing literature to the authors’ knowledge that specifies the size at which repair becomes necessary. However, since the PSA is a developmental leftover of the iliac artery, repair should be carried out following the same guidelines as set for iliac artery aneurysms, i.e., when the aneurysm reaches a size of 3.5 cm. This, however, needs more research and long-term monitoring. In this case, the size of the aneurysm was around 4 cm.

Open repair of the PSAA has been described in the literature. This approach, although successful, is associated with a high degree of morbidity and injury to the sciatic nerve due to its close proximity to the PSAA, resulting in foot drop.⁷

Charisis et al.’s review focused on endovascular treatment of PSAAs using primary stenting. The study included 15 cases with patients’ median age of 66 years. Post-treatment, all were symptom-free. The results suggested that this treatment is safe and effective in selected cases.⁸

In the present case, after a thorough discussion with the multi-disciplinary team, the hybrid approach similar to the one described by de Boer et al. in 2022 was opted, and the open approach was dropped.⁹ A femoropopliteal bypass and plug occlusion of the PSAA was planned. No plan to excise the aneurysm was made to prevent any sort of nerve injury. The endovascular approach successfully plugged the aneurysm, and an immediate open femoral-popliteal bypass graft was placed successfully. The ischaemia time was kept as short as possible. Blood supply to the limb was successfully restored.

This surgical approach was safe and effective, leading to sac regression with symptom relief, preventing limb ischaemia and decreasing the morbidity associated with the natural disease progression of SAA.

This case report demonstrated that the hybrid surgical method of incorporating both open femoropopliteal bypass and endovascular plugging of the SAA minimised patient morbidity and achieved a favourable outcome.

PATIENT’S  CONSENT:
Patient consented to using the data before the procedure without disclosing the patient's identity. Another verbal consent was obtained over the telephone before submitting the paper.

COMPETING  INTEREST:
The  authors  declared  no  conflict  of  interest.

AUTHORS’  CONTRIBUTION:
OE: Conception and design of the study, critical revision of the manuscript for important intellectual content, and agreement to be accountable for all aspects of the work.
JA: Data acquisition and interpretation, critical revision of the manuscript for important intellectual content, and agreement to be accountable for the integrity and accuracy of the work.
UAK: Study design and methodology, data analysis, manuscript drafting, and responsible for the content of the work.
TK: Formulating the research question and study design, data analysis and interpretation, critical revision, and editing of the manuscript.
HW: Supervision of the research process, study design and manuscript revision, expert reviewing for accuracy and integrity, approval of the final version, and agreement to be accountable for all aspects of the study.
All authors approved the final version of the manuscript to be published.
 

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