Intraoperative Doppler flowmetry evaluation of humeral head perfusion after proximal humerus fracture

Abstract

Background: Understanding vascularity and assessing the risk of post-traumatic avascular necrosis are crucial for predicting outcomes and identifying optimal treatment options in proximal humerus fractures (PHFs). Until now, Hertel et al have been the only researchers to evaluate the intraoperative perfusion of the humeral head after fracture using Doppler flowmetry in a central single drill hole within the head. This pilot study aims to standardize the evaluation of intraoperative perfusion measurements in different areas of the humeral head in patients with PHF.

Methods: In this prospective pilot study, intraoperative semiquantitative Doppler perfusion measurements were conducted during plate osteosynthesis for PHF treatment in our institution between July 2021 and May 2022. The fracture morphology was classified radiologically according to Resch's criteria. Quality of reduction was determined postoperatively to be either anatomical, minor malreduced, or major malreduced according to Peters et al in conventional and computed tomography examinations. Medial hinge integrity and medial metaphyseal extension were assessed radiographically according to Hertel et al. Intraoperatively, after drilling screw holes through the plate, a Doppler probe was inserted through all nine drill holes on the humeral head and at least one on the humeral shaft to successively measure the presence of a pulse to indicate if perfusion is present.

Results: A total of ten patients (mean age 59 years, range, 36-83) with a humeral head fracture (2 × 2GL, 3 × 3G, 2 × 4G, 2 × 4GL, 1 × 5aG according to Resch) were included. Nine of the ten patients showed a pulse signal on the humeral shaft. Overall, pulse-synchronous perfusion was detected using Doppler sonography in at least one hole in the humeral head of all patients. In patients with an intact medial hinge (N = 6), pulse-synchronous perfusion could be measured in almost twice as many humeral head holes on average (5.7 vs. 3.0 drill holes) compared to patients with a dislocated medial hinge (N = 4). In patients with metaphyseal extension (N = 3), pulse-synchronous perfusion was measured in an average of 6.7 humeral head holes compared to 3.7 holes in patients without metaphyseal extension (N = 7).

Conclusion: Semiquantitative, intraoperative Doppler flowmetry offers a noninvasive and rapid assessment of humeral perfusion which allows an understanding of humeral head perfusion, when used in a standardized fashion to measure flow in different areas of the humeral head.

Keywords: Avascular necrosis; Doppler flowmetry; Doppler sonography; Post-traumatic osteonecrosis; Proximal humerus fracture; Pulse-synchronous perfusion.

Figure 1

Intraoperative fluoroscopy view illustrating anteroposteriorly the Doppler probe inserted into the cancellous bone through the posterior E hole of the plate postdrilling.

Figure 2

Examples of perfusion measurements in drill holes of a female patient with an approximate heart rate of 100/min. (A) No significantly outlying amplitude height can be seen between 1.3 and 1.4 Hz, indicating no existing perfusion in the drill hole measured. (B) A significantly outlying amplitude height can be seen between 1.3 and 1.4 Hz, serving as proof of perfusion in the drill hole measured.