Abstract

Wendy De Vos¹, Ludwig Van den Berghe¹, Leen Paelinck¹, Sabrina Vansteenkiste¹, Brenda Depaepe¹, Sandra Lauwers¹, Julie Mortier¹, Emma De Rijcke¹, Axel Van Damme¹, Katrien Vandecasteele¹

¹UZ Ghent, Radiotherapy, Ghent, Belgium

Despite international guidelines advise the use of frog-leg position in vulvar irradiation, many centers still use supine position. The frog-leg position is often uncomfortable and difficult to reproduce. Online imaging and the decision of Radiotherapists (RTTs) whether or not to reposition is time-consuming. We aim to find out which positioning-accessories enable us to realize the fastest, highest reproducible and most comfortable frog-leg positioning technique for the (mostly elderly) vulvar cancer patients and compare this with the currently used supine positioning technique.

We performed an observational study using fieldwork and a structured observation.

The used positioning techniques are illustrated in figure 1. For frog-leg positioning a blue knee cushion, a vacuum mattress and an immobilization mask (all ORFIT industries) were used. For supine position, we used a red knee cushion (CIVCO industries).

Five voluntary RTTs (mean age: 35y) underwent all 4 positioning techniques. Five patients (mean age: 72y) being treated for vulvar cancer were positioned using the blue knee cushion or the vacuum mattress. Per individual positioning device, reproducibility, time (T) (rapid positioning is indicative for the reproducibility and important for patient comfort) and comfort was scored.

Reproducibility was scored by the investigators using a score from 1 (very difficult) to 5 (very easy)

T: was measured using 3 time-frames:

-T1: from the moment that the patient/volunteer lies on the table until the moment of correct positioning.

-T2: on-line imaging and treatment.

-T3: time to get the patient/volunteer from the treatment table.

Comfort was scored by the volunteers/patients with numbers from 1 (no comfort) to 5 (very comfortable).

Reproducibility

The blue knee cushion scored best in the patients while for the volunteers the immobilization mask was best. Given the unavailability of the immobilization masks in clinical routine, this has not (yet) been tested in patients. The reproducibility of the blue knee cushion and the vacuum mattress is comparable but not optimal in both groups.

Time registration

Both patient and volunteer positioning (T1) were fastest using the blue knee cushion. It took on average twice as long to get the patients off the treatment table compared to the volunteers when using the vacuum mattress. This is probably due to the age difference. When we include the scores of the red knee cushion, it has the best scores at any time.

Comfort

The vacuum mattress was experienced the least comfortable for both groups. The volunteers reported pain in the shoulders using all devices, including the immobilization mask where the arms are placed high on the chest instead of above the head. 

We have found that the immobilization mask has advantages in reproducibility and comfort. We think to extend the use of this device even further to all treatments where the use of a frog-leg position is recommended.