Severe Hemodynamic Collapse During Humerus Stabilization with Photodynamic Implant: A Report of Two Cases

Abstract

Case:

We present two cases of severe hemodynamic collapse during prophylactic stabilization of impending pathologic humerus fractures using a photodynamic bone stabilization device. Both events occurred when the monomer was infused under pressure into a balloon catheter.

Conclusion:

We suspect that an increase in intramedullary pressure during balloon expansion may cause adverse systemic effects similar to fat embolism or bone cement implantation syndrome. Appropriate communication with the anesthesia team, invasive hemodynamic monitoring, and prophylactic vent hole creation may help mitigate or manage these adverse systemic effects.

Introduction

Surgical management of humeral metastatic disease can be accomplished by plate osteosynthesis (with or without intralesional curettage and cement augmentation), intramedullary nail fixation, or—the most recent option—stabilization with a photodynamic implant^1–3. The IlluminOss Photodynamic Bone Stabilization System (IlluminOss Medical, Inc., East Providence, RI, USA) involves the insertion of a Dacron balloon catheter into the medullary canal, which is then infused with a liquid, photosensitive monomer under pressure. This expands the balloon to fill the canal and thus provides stability via interference fit against the intact cortices⁴. Fiber-optic blue light is then introduced, which induces polymerization and solidification of the monomer. Initial reports of humerus stabilization using photodynamic implants have not described significant intraoperative or early postoperative complications, apart from those related to wound healing or implant failure⁴.

Adverse cardiopulmonary effects during intramedullary instrumentation, most often of the femur, have been well described in the form of fat embolism syndrome (FES) during fracture stabilization and bone cement implantation syndrome (BCIS) during arthroplasty^5–8. An increase in intramedullary pressure, prompting extravasation of medullary contents into the circulation via the endosteal vasculature, has been implicated in both processes^{7, 9–12}. It follows that expansion of a photodynamic intramedullary balloon may produce an analogous effect in some patients. However, no such reports exist in the current literature.

Herein, we present two cases in which the IlluminOss Photodynamic Bone Stabilization System was used to prophylactically stabilize impending pathological fractures of the humerus. Both cases were complicated by severe intraoperative cardiopulmonary compromise at the time of the monomer infusion into the balloon catheter. Patients provided verbal consent for their cases to be submitted for publication.

Case Reports

Case 1

A 44-year-old male patient with a recently diagnosed biopsy-proven malignant solitary plasmacytoma presented with an impending pathological fracture of the right humerus (Figure 1). He was otherwise in good health and had no significant medical history or preexisting medical comorbidities. Preoperatively, his hemoglobin level was 15.6 g/dL and his platelet count was 326,000/mcL, both of which were within normal limits. Due to the patient’s severe functional right arm pain and the large lytic nature of the lesion, prophylactic stabilization was indicated.

Figure 1:

Preoperative radiograph of right humerus with large, lytic lesion evident (Patient 1).

During surgery, the medullary canal was accessed from the proximal humerus with a curved awl, and the balloon catheter was successfully and uneventfully introduced (Figure 2) and advanced. The balloon was then infused with liquid monomer. Near the conclusion of the infusion, the patient’s systolic blood pressure decreased from 115 mmHg to 65 mmHg, and the fraction of inspired oxygen he required increased from 62% to 97%. His blood pressure responded to a 10-mg bolus of ephedrine. After the patient’s hemodynamic status stabilized, the procedure was successfully completed (Figure 3). Postoperatively, the patient remained intubated and required vasopressor support until the following day. His postoperative chest radiograph did not demonstrate significant interval change from before surgery. The critical care team diagnosed acute postoperative hypoxic respiratory failure without an alternative cardiopulmonary etiology. The patient’s pulmonary function returned to baseline, and he was safely discharged on the fourth postoperative day. He underwent adjuvant radiation postoperatively (45 Gy) and was started on systemic lenalidomide. With his pain significantly diminished, he was able to resume activities of daily living.

Figure 2:

Intraoperative fluoroscopic image depicting insertion of photodynamic implant into right humerus (Patient 1).

Figure 3:

Postoperative radiograph of right humerus after intramedullary stabilization with photodynamic implant (Patient 1).

Case 2

A 79-year-old female patient with widely metastatic non-small cell lung carcinoma presented with an impending pathological fracture of the left humerus (Figure 4). She had discrete lytic lesions in both the diaphyseal and distal metaphyseal humerus. Of note, she had impaired pulmonary function due to recurrent malignancy in the lung as well as emphysema in the context of a 64-pack-year smoking history (Figure 5). Her emphysema was well-controlled with a fluticasone-umeclidinium-vilanterol nebulizer (once daily) and albuterol sulfate (as needed), and she did not require supplemental oxygen. She had a two-month history of progressive left elbow pain, which was severe and limited her activities of daily living. Thus, prophylactic stabilization was indicated. Due to the extent of the patient’s osseous involvement, we stabilized the diaphysis with a photodynamic nail, which overlapped with the reconstruction of the metaphyseal lesion involving cement and orthogonal plates.

Figure 4:

Preoperative radiograph of left humerus with osteolytic diaphyseal and distal metaphyseal changes (Patient 2).

Figure 5:

Preoperative radiograph of chest (Patient 2).

During the surgery, with the patient in lateral decubitus, a paratricipetal approach was made to the distal humerus. The metaphyseal lesion was curetted, the medullary canal was accessed posteriorly, and the balloon catheter was introduced uneventfully in a retrograde fashion. Approximately 2 minutes after completion of monomer infusion, the patient’s systolic blood pressure decreased from 110 mmHg to an undetectable level. She required an increased fraction of inspired oxygen (from 54% to 90%) and a 10-mg bolus of ephedrine, followed by sequential 40-, 80-, and 120-mcg boluses of phenylephrine. As the monomer had not yet been cured, the balloon was rapidly deflated, and the surgery was paused as hemodynamic stability was restored. A second inflation of the balloon was then attempted at a much slower rate than the standard rate. Despite the gradual injection, the patient’s blood pressure again declined 2 minutes after completion of the injection. As the blood pressure remained above the critical level, the balloon was left inflated; however, polymerization was delayed while the blood pressure gradually normalized over a period of approximately 10 minutes. Polymerization then proceeded and the surgery was completed safely (Figure 6 and Figure 7). The patient was extubated at the conclusion of surgery but required high-flow supplemental oxygen, from which she was unable to be weaned until the sixth postoperative day. Her postoperative chest radiograph (Figure 8) demonstrated interval development of bilateral patchy airspace opacities and small pleural effusions. The critical care team diagnosed acute postoperative hypoxic respiratory failure without an alternative cardiopulmonary etiology. The patient was safely discharged on the eighth postoperative day.

Figures 6 and 7:

Postoperative radiographs of left humerus after curettage and cementation, intramedullary stabilization with photodynamic implant, and bicolumnar plate fixation (Patient 2).

Figure 8:

Postoperative radiograph of chest (Patient 2).

Discussion

We described two patients who experienced significant intraoperative hemodynamic instability and acute postoperative hypoxic respiratory failure following stabilization of humeral metastatic disease with an intramedullary photodynamic implant. Both instances of hemodynamic collapse occurred at the conclusion of the monomer infusion, suggesting that elevated intramedullary pressure was the causative mechanism. One purported advantage of the IlluminOss system is that the implant expands and conforms to the contour of the medullary canal, allowing improved stability⁴. However, drawing on lessons learned from FES and BCIS, we hypothesize that the increase in intramedullary pressure that accompanies balloon expansion may lead to extravasation of medullary contents into circulation, which in turn may cause adverse systemic effects^{9, 11–13}.

Both of our patients were treated for impending rather than completed pathologic fractures. We posit that, in this setting, the intact medullary canal creates a closed system that leads to greater pressurization during balloon inflation. Without a route of egress through a completed fracture site, medullary contents are directed towards endosteal vessels and systemic circulation.

Several practical changes may improve the safety profile of skeletal stabilization with photodynamic implants. Evacuating the canal of marrow and tumor with suction prior to device insertion can minimize the potential embolic load. The surgeon should directly communicate with the anesthesia team prior to monomer infusion to allow for optimization of hemodynamic status, and should maintain communication throughout balloon inflation. Invasive monitoring using the arterial line, advocated for patients with a high risk of BCIS, should be strongly considered, especially in patients with impaired cardiovascular or pulmonary function at baseline¹⁴. Prophylactic creation of a distal vent hole, as has been described in both nail stabilization and cemented arthroplasty, may also reduce intramedullary pressurization, thus mitigating the risk of adverse systemic effects^{15, 16}. Slow, incremental infusion of the monomer may help avoid a sudden efflux of medullary contents into systemic circulation. Even when these precautions are taken, surgeons should keep the risk of severe cardiopulmonary compromise in mind.