A coil in the hair—a case report of percutaneous coil migration
Coil migration following cerebral aneurysm treatment has been described and may result in stroke, recurrent aneurysm, or local mass effect. Cerebral coil embolization is also applied in arteriovenous malformations and arteriovenous fistulas, but these pathologies are relatively rare and coil migration is not as well described. Furthermore, these cases are more commonly treated with combinations of multiple modalities to achieve cure. Embolization, surgery, and radiation each have risks and benefits and combinations may have synergistic risks and benefits not seen in monotherapy. We report a case of extravascular and extra-corporeal coil migration after embolization and craniectomy to treat a patient with hemorrhage from an arteriovenous fistula.
KeywordsForeign body migration Therapeutic embolization Craniotomy Intracranial arteriovenous malformations Cerebral hemorrhage
Background and importance
Even though hybrid open cerebrovascular and neuroendovascular approaches have been performed for many years, recently, they are increasingly applied to treat challenging pathology as more medical centers install hybrid operating-angiography suites. In a positive feedback loop, increasing experience with the hybrid environment has allowed more aggressive treatment of complex cerebrovascular disease which previously may have been considered incurable [1, 2]. However, the complications of hybrid approaches are not as well understood and may be distinct from the complications of each technique in isolation. Intracranial coil embolization via a femoral arterial approach is not known to have a risk of trans-cutaneous migration. This case introduces the concept of unforeseen complications due to new hybrid approaches.
Clinical presentation/case report
The patient received flucloxacillin, a standard first-line antibiotic agent at UMC, and taken to the operating room for resection and washout. Dissection exposed the subgaleal-epidural space. Intradural exploration was not pursued, but the coil was transected at the dural surface (Fig. 1d). An acrylic cranioplasty flap was applied. The patient recovered well from this procedure and had no further complications. Follow-up of the arteriovenous fistula demonstrated no further arteriovenous shunting or venous congestion.
Migration is a known complication of coil embolization. In particular, intravascular migration into an unintended vessel is frequently observed intraprocedurally and may result in incomplete embolization or off target embolization, occurring in approximately 3% of cases . The subarachnoid space is a second location for coil migration and may be the underlying cause of long-term recanalization in as many as 55% of embolized aneurysms . Extravascular coil migration may lead to recurrent risk of aneurysm rupture and local mass effect on cranial nerves . However, extra-corporeal migration of coils is not a known complication of intracranial coil embolization. This case represents a novel complication unique to the evolving field of hybrid open-endovascular treatments.
Coil embolization is also applied in the systemic endovascular therapy for pseudoaneurysms. In the superficial coil embolization with thin overlying soft tissue, such as at the posterior tibial artery, coil migration may develop a cutaneous wound . However, due to the calvarium, neuroendovascular coil embolization in general is not susceptible to this complication. In the presented case, the combination of a superficial convexity embolization target and the craniectomy minimized the barriers to cutaneous migration. In the setting of craniectomy, cerebral pulsations and cerebral spinal fluid flow are also altered, which may have increased a propensity for coil migration.
Some find the trans-venous approaches safer than trans-arterial approaches in the treatment of this type of AVF. However, specific to the trans-cranial trans-venous approach sometimes, in the final stages of embolization, when the sinus is largely occupied by the coils, the angiocatheter, that is short and unstable, can be displaced out of the sinus with partial protrusion of the extremity of the last coil through the dural breach. In this case, the healing of the fistula is not compromised, but in the absence of bony coverage then over time the metallic material may progressively pass through the overlying soft tissue and expose the patient to the risk of infection.
Hybrid operating and angiography suites are increasingly common. As hybrid practitioners refine novel techniques, previously unforeseen challenges and complications are expected to arise . Combined endovascular and surgical treatments for arteriovenous fistulas and malformations are indicated only when the combined risk-benefit profile is better than that of monotherapy. This complication is a unique result of combinatorial therapy. After embolization, during the open surgery, resection of embolic product such as coils or liquid embolic agents may eliminate this possibility. Early cranioplasty may also prevent this complication.
The patient presented with a non-infected cutaneous wound from extravascular coil migration 6 weeks after hybrid open-endovascular approach to coil embolization of an AVF. Extradural coil mass was resected and a synthetic cranioplasty flap was applied. This case demonstrates a potential synergy of risks in hybrid open and endovascular therapies, resulting in new unforeseen complications.
Compliance with ethical standards
The patient has consented to the submission of the case report for submission to the journal.
Conflict of interest
The authors declare that they have no conflict of interest.
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