The Photodynamic Bone Stabilization System: a minimally invasive, percutaneous intramedullary polymeric osteosynthesis for simple and complex long bone fractures

Abstract

The treatment of osteoporotic long bone fractures is difficult due to diminished bone density and compromised biomechanical integrity. The majority of osteoporotic long bone fractures occur in the metaphyseal region, which poses additional problems for surgical repair due to increased intramedullary volume. Treatment with internal fixation using intramedullary nails or plating is associated with poor clinical outcomes in this patient population. Subsequent fractures and complications such as screw pull-out necessitate additional interventions, prolonging recovery and increasing health care costs. The Photodynamic Bone Stabilization System (PBSS) is a minimally invasive surgical technique that allows clinicians to repair bone fractures using a light-curable polymer contained within an inflatable balloon catheter, offering a new treatment option for osteoporotic long bone fractures. The unique polymer compound and catheter application provides a customizable solution for long bone fractures that produces internal stability while maintaining bone length, rotational alignment, and postsurgical mobility. The PBSS has been utilized in a case series of 41 fractures in 33 patients suffering osteoporotic long bone fractures. The initial results indicate that the use of the light-cured polymeric rod for this patient population provides excellent fixation and stability in compromised bone, with a superior complication profile. This paper describes the clinical uses, procedural details, indications for use, and the initial clinical findings of the PBSS.

Keywords: bone density; long bone fracture; orthopaedics; osteoporosis; polymeric rod; surgery.

Figure 1

The PBSS utilized in a distal ulna fracture. Notes: (A) Preoperative radiographs demonstrating distal ulna fracture. (B) Perioperative radiograph illustrating the PBSS in situ with radiopaque markers visible. Postoperative range of motion in flexion (C), and extension (D). Abbreviation: PBSS, Photodynamic Bone Stabilization System.

Figure 2

Schematic representation of the Photodynamic Bone Stabilization System. Notes: The balloon catheter is inserted into the medullary cavity of the fractured bone and the fracture stabilized. The monomer is injected through a standard syringe into the catheter. Polymerization is accomplished via a fiber optic light pipe inserted into the central lumen of the catheter. Abbreviation: PET, polyethylene terephthalate.

Figure 3

The Photodynamic Bone Stabilization System implant in combination with standard compression plate hardware. Notes: The PBSS implant fills the entirety of the medullary cavity, contacting the cortical margins of the fractured bone (yellow arrow). Abbreviations: PBSS, Photodynamic Bone Stabilization System; L, left.

Figure 4

Histologic images showing the Photodynamic Bone Stabilization System in situ. Notes: The balloon and polymer fill the entire medullary space, with the balloon remaining in close contact with the cancellous bone following hardening (A & B, black arrow). The central lumen allowing light pipe access during the polymerization process is visualized in cross-section (B, yellow arrow).

Figure 5

A comparison of the thermal excursion and curing time of the PBSS monomer (blue) and PMMA (red). Notes: PBSS demonstrates a lower maximum temperature and a shorter curing time when compared with PMMA, which exhibits a long-term response at elevated temperatures above normal body temperature. Abbreviations: Illum, IlluminOss PBSS monomer; PMMA, polymethylmethacrylate.