Magnetically Driven Intramedullary Limb Lengthening in Patients with Pre-existing Implanted Programmable Devices: A Case Series

Abstract

Aim: The aim of the study is to demonstrate the safety and efficacy of the use of magnetically controlled intramedullary nails in patient with programmable implantable devices.

Background: Magnetically driven intramedullary limb lengthening devices have revolutionised the field of limb reconstruction. Because the system is powered by strong magnets, there are warnings to avoid the use of the device in patients with implanted programmable devices, such as cardiac pacemakers.

Materials and methods: Four patients with three different types of programmable implanted devices presented to two centres for limb lengthening and limb reconstruction. Each patient had a limb length discrepancy and desired correction using an intramedullary lengthening device. After thorough counselling about the potential risks and benefits of the procedure as well as discussions with each patient's medical team, the decision to proceed with surgery was made.

Results: All four patients underwent osteoplasty with insertion of a magnetically driven intramedullary lengthening nail. Goal length was achieved with successful consolidation and subsequent nail removal in all patients. There were no malfunctions of the implantable devices during the distraction phase in any of the patients.

Conclusion: With proper precautions, intramedullary lengthening can be performed safely and successfully using a magnetically driven nail in patients with previously implanted programmable devices.

Clinical significance: This initial experience suggests use of magnetically controlled intramedullary nails in patient with programmable implantable devices can be undertaken safely within constraints of precautions.

How to cite this article: Iobst CA, Hatfield DN, Forro SD, et al. Magnetically Driven Intramedullary Limb Lengthening in Patients with Pre-existing Implanted Programmable Devices: A Case Series. Strategies Trauma Limb Reconstr 2023;18(2):111-116.

Keywords: Intramedullary limb lengthening; Limb length discrepancy; Pacemaker.

Figs 1A to E

(A) Pre-operative standing radiograph demonstrating varus deformity of the right lower extremity and leg length discrepancy of approximately 2.5 cm; (B) Radiograph demonstrating location of cardiac pacemaker at about the level of the third lumbar vertebra on the right side of the abdomen; (C) Photograph in the pre-operative holding area demonstrating the cardiology team assessing the function of the pacemaker while the ERC was being used at the anticipated magnet location in the right distal femur; (D) Post-operative radiograph demonstrating consolidation of the regenerate bone after lengthening and deformity correction with the magnetically driven intramedullary lengthening nail; (E) Post-operative image after nail removal demonstrating full consolidation of regenerate bone

Figs 2A to E

(A and B) Pre-operative weight-bearing anteroposterior (AP) and lateral radiographs of patient's non-united ankle fusion demonstrating collapse and shortening; (C) Postoperative lateral radiograph showing compressed arthrodesis site with PRECICE nail with anterior plate spanning the junction with the head of the talus and anterior calcaneus in addition to the osteotomy with lengthening; (D) Postoperative AP radiograph after lengthening of 5.6 cm, demonstrating excellent regenerate formation as well as healing fusion site; (E) Postoperative standing bone length radiographs demonstrating equal leg lengths

Figs 3A to D

(A) Pre-operative standing radiograph demonstrating approximately 7 cm leg length discrepancy; (B) Abdominal radiograph demonstrating the location of the gastric pacer on the right side at about the level of thoracic vertebra eleven; (C) Post-operative radiograph demonstrating consolidation of the regenerate bone after 5 cm lengthening; (D) Post-operative radiograph after nail removal demonstrating full consolidation of the regenerate bone

Figs 4A to D

(A) Pre-operative standing radiograph demonstrating a leg length discrepancy of approximately 2.5 cm on the left; (B) Lateral head and neck radiograph demonstrating the location of the programmable valve attached to the ventriculoperitoneal shunt; (C) Post-operative radiograph demonstrating consolidation of the regenerate bone after lengthening; (D) Post-operative radiograph after nail removal demonstrating full consolidation of the regenerate bone