Study design and data collection
A quasi-randomized comparative study including 30 unilateral postmastectomy lymphedema (UPML) patients was performed. The study was conducted in the Physical Therapy Department at the National Cairo Institute in Egypt from June 2018 to August 2019. The research ethics committee of the Faculty of Physical Therapy at Cairo University approved this study. All included patients signed informed consent forms before the start of data collection.
The aim of this study was to compare the therapeutic efficiency of VR and PNF in treating lymphedema and improving function in UPML patients. The study design was parallel, and the patients were subdivided into two equal groups, with 15 patients in each. The quasi-sampling method was performed by the alternative allocation of patients in both groups. This was not a blinded study (Fig. 1).
Only female patients were included. Their age range was from 40 to 65 years. The patients had UPML. All patients had undergone modified radical mastectomy with axillary lymph node dissection. The postsurgical duration was at least 6 months. The inter-limb volume difference was at least 5%, which was calculated by the truncated cone formula. The patients were categorized as having stage I or stage II lymphedema, according to the International Society of Lymphology classification system. Stage I represents an early accumulation of fluid relatively high in protein content (e.g., in comparison with “venous” edema), which subsides with limb elevation. The pitting phenomenon may occur. An increase in various types of proliferating cells may also be observed. Stage II shows that limb elevation alone rarely reduces tissue swelling, and the pitting phenomenon is obvious. Later, in stage II, the limb may not pit as excess subcutaneous fat, and fibrosis may develop. At each stage, the severity can be determined by the difference in the limb volume between the affected and unaffected limb as follows: minimal (a 5 to 10% increase in the volume), mild (a 10 to 20% increase in the volume), moderate (a 20 to 40% increase in the volume), or severe (a 40% or higher increase in the volume) [18]. Patients with musculoskeletal or neurological disorders that can impair performance during training and testing, visual disorders that can affect video game-based exercise performance, uncontrolled cardiovascular or pulmonary diseases, psychiatric illness, bilateral lymphedema, elephantiasis, current metastases, continuing radiotherapy, or venous thrombosis were excluded. The included patients did not undergo physical therapy before the current treatment, or the last time they participated in therapy sessions was at least 3 months ago.
The patients in the VR group were asked to freely move the shoulder joint. After this warm-up, the patients practiced a 30-min exercise program using a Nintendo Wii® video game. During the sessions, the patients stopped for 1 min between games [19]. Tennis, triceps extension, and rhythmic boxing were the games used. The patients participated in 2 sessions per week for 4 weeks.
For the PNF group, the starting position for the exercise was in the supine position, with the shoulder joint extended, adducted, and internally rotated; the elbow extended; the forearm pronated; the wrist flexed; and the fingers flexed. The patients slowly stretched their shoulders by flexing, abducting, and externally rotating them; extending their elbows; and supinating their forearm. They slowly stretched their wrist and fingers by extending them and pointing their thumbs towards the floor. This stretch was combined with inspiration followed by holding the breath at the end position for 5 s. Afterwards, while expiring, the patients slowly returned their arms to the starting position. This exercise was performed 10 times, followed by 1 min of rest, and repeated for 30 min [15]. The patients participated in 2 sessions per week for 4 weeks.
Both groups underwent 20 min of pneumatic compression at a pressure of 60 mmHg twice a week for 4 weeks. A multi-sleeve device was used [20]. In addition to 30 min of MLD twice a week for 4 weeks, a home program including elevation, positioning, exercises, and skincare advice was performed. Multi-layer bandaging was not applied due to patient incompliance. Educational instructions were given to the patients in printed handouts. These instructions regarded the lymphatic system and its function, precautions (e.g., avoiding subjecting the affected limb to heat), and figures showing the home program exercises.
In the assessment, the circumferential method and the truncated cone formula were used to calculate the volumes, and the Arabic version of the QuickDASH-9 scale was used to assess upper limb function.
Circumferential measurements
Circumferential measurements depend on specified distances along the length of the limb, but the hand volume cannot be calculated. This method provides information on the localization of the swelling [16].
In the current study, the circumference of the upper limb was measured every 4 cm from the wrist and to the axilla, and the volume was calculated with the truncated cone formula (as the limb is viewed as a series of truncated cones or frustum-shaped segments). The volume of each segment = L/12π (C12 + C1 C2 + C22), where C1 and C2 are the circumferences of the ends of a segment length (L). The total limb volume was defined as the sum of the segment volumes [21]. The excessive volume of the UPML was calculated by subtracting the volume of the non-affected upper limb from that of the lymphedematous upper limb. The excess arm volume (EAV) = VL − VH, where VL refers to the lymphedematous limb’s volume, and VH refers to the healthy extremity’s volume. The EAV was measured before and after treatment. These measurements were taken before treatment and after 4 weeks of treatment for both groups. Then, the percent improvement in the EAV was calculated by the equation [(pre EAV − post EAV) × 100/pre EAV] to compare the magnitude of improvement between the two groups [22].
QuickDASH-9 scale
The affected upper limb function was assessed using the validated Arabic version of the QuickDASH-9 scale before the treatment and after 4 weeks of treatment for both groups. It includes 9 items, and each item in the QuickDASH-9 is scored on a 4-point Likert scale (0–4); a higher value corresponds to greater disability/severity of symptoms and reduced function. A scaled score can be derived even if one item is missed. The total scores are converted into a scaled score (0–100) using a formula. The Arabic QuickDASH-9 score = [(sum) × 1.1] × 5/2, and a missing response is replaced by the average of the remaining scores [23]. Then, the percent improvement in the QuickDASH-9 score was calculated by the following equation: [(pre-treatment score − post-treatment score) × 100/pre-treatment score].
Statistical methods
The data were processed and analyzed using the statistical package for the Social Sciences (SPSS), version 25 (IBM Corp., Armonk, NY, USA). The data are summarized as follows:
- 1.
Means ± standard deviations (SD) for data with normal distribution {the age, weight, height, and body mass index (BMI)}.
- 2.
Median (interquartile range [IQR]) for data with non-normal distribution {number of dissected lymph nodes, QuickDASH-9 scores, and EAV}.
- 3.
Frequencies (number of cases) and relative frequencies (percentages) for nominal variables {handedness, menopause status, and stage of lymphedema}.
The non-parametric Mann-Whitney U test and non-parametric Wilcoxon signed-rank test were used to compare the EAV and the QuickDASH-9 scores between groups and between the pre- and post-intervention time points within each group, respectively. The Shapiro–Wilk test was used to assess normality [24]. The correlations between quantitative variables were assessed using the Spearman correlation coefficient [25]. The statistical significance level was set to be 0.05.