Outcome measures
All participants had their scar assessed after three weeks, six months
and twelve months after removal of the CVC. The assessment was conducted
by a study nurse and a dermatologist. The dermatologist had fewer
observations than the study nurse. The study nurse assessed the scar by
using the Vancouver Scar Scale (VSS) [8] and the Patient and
Observer Scar Assessment Scale (POSAS) version 1 [9] at each
clinical check every three weeks, six months and twelve months, after
removal of the CVC. The parents and patients assessed the POSAS three
weeks, six months and twelve months at the clinical check. Digital
clinical images of the scar were taken after three weeks, six months and
twelve months after removal of the CVC by a professional clinical
photographer affiliated with Aarhus University Hospital. In all
pictures, a ruler was applied to the skin, allowing the scar width to be
standardized. The clinical images were provided blinded to the
dermatologist for assessment of VSS and scar width. In the present
study, the dermatologist categorized the interventions groups´ skin type
according to Fitzpatrick skin type classification scale [10].
Patients with a Fitzpatrick 3 or higher skin type are more likely to
develop keloid scar formation [11]. However, this is not clear for
hypertrophy [12].
The VSS assesses four variables: Pigmentation, pliability, height and
vascularity. It has a total score of 14, where 0 is equivalent to the
patients´ normal skin [9]. The POSAS consists of two scales: One
completed by the patient and one by the observer. The patients’ scale
contains six questions with regards to relief, pain, color, pliability,
thickness and itching. The observer scale involves five questions
regarding to pliability, thickness, relief, pigmentation and
vascularity. Each parameter uses a 10-point scoring system, with 1
representing normal skin and 10 corresponding to the worst imaginable
scar. The total score of the patient scale consists of adding the scores
of each of the six items from 6 to 60. The observer scale consists of
five items and therefore, the total score ranges from 5 to 50. At total
score of 6 and 5, respectively, reflects normal skin [9]. The main
outcome was the Vancouver Scar score. Secondary outcomes were scar width
and scar quality measured using the POSAS.