Head Positioning Monitor: Device for Objective Quantification of Patient Compliance

Abstract

Abstract: : Purpose:The primary patient-determined variable in the successful outcome of macular hole surgery is the patient’s ability to maintain the proper head position to hold an intraocular gas bubble against the macular hole. Because proper positioning involves significant musculoskeletal discomfort to the patient, compliance is a problem. Quantifying the time that the patient maintains the proper position could provide effective feedback to the patient on his/her effort in meeting goals for compliance: Y% of proper head positioning leads to Z% success rate. This information may also have medicolegal ramifications in assigning the contributing factors for treatment failure. Methods: A simple device to measure the amount of time that a patient’s head has spent in the prescribed position has been constructed with two mercury tilt switches, a timer, and a power source. The circuit is miniaturized to fit comfortably around the head without any noticeable protrusion. Mercury tilt switches complete an electric circuit when in a predetermined tilt. Therefore, the circuit is constructed in such a way that it is complete only when the device is in the proper position. The timer is a continuous, cumulative timer that records the amount of time that the circuit is active without resetting. After placing the subject in a proper head position, the device is placed on the head. The tilt switches are activated with the head in the desired position. The circuit is complete only in this position and the timer is therefore running only in this position. If the patient’s head moves out of this position, the mercury switches tilt and deactivate the circuit. Results: This device has been tested in a pilot trial and was worn comfortably around the head. Further, the device was able to measure the amount of time that a subject was able to stay in a prescribed head position in a given time period. Conclusions: Objective measurement of the total time spent by a patient with his/her head in the proper position to maximize the tamponading effect of an intraocular gas bubble after macular hole surgery will provide beneficial information to the patient and the surgeon. In the next phase, we hope to gather a quantity of data sufficient to correlate the amount of time spent in the proper head position to the success rate of the surgery.

Keywords: vitreoretinal surgery • macular holes