Donor-site morbidity after fibula free flap transfer: a comparison of subjective evaluation using a visual analogue scale and point evaluation system

Abstract

The aims of this study were: (1) to compare the visual analogue scale (VAS) with the point evaluation system (PES) in the subjective evaluation of donor-site morbidity after fibula free flap transfer; (2) to compare the functional outcomes of fibula free flap surgery between patients with a normal body mass index (BMI) and patients with a high BMI, and between skin paddle and non-skin paddle harvesting; and (3) to determine the correlation between functional outcomes and related factors. This study included 15 patients who underwent a vascularized fibula free flap transfer for oral and maxillofacial reconstruction. Demographic data, preoperative, intraoperative, and postoperative data were collected. Subjective self-evaluation of functional outcomes was done using a VAS followed by a PES. Comparison of the VAS and PES scores was assessed with Pearson’s correlation coefficient. The statistical significance was set at P < 0.05. The VAS score was significantly correlated with the PES score ( r = 0.63, P = 0.01). The tourniquet times for the skin paddle group were longer than for the non-skin paddle group ( P = 0.02), while the satisfaction score of the non-skin paddle group was higher than that of the skin paddle group ( P = 0.03). The VAS is a potential option for the subjective evaluation of donor-site morbidity after fibula free flap transfer.

Vascularized bone grafts are widely used in oral and maxillofacial reconstruction due to less bone resorption, the ability to reconstruct large maxillofacial defects, allowing independence from the tissue bed, and offering the chance to do one-stage soft tissue and bone reconstruction. There are several donor sites available for vascularized bone grafts. The fibula bone is the most commonly used in oral and maxillofacial reconstruction following benign or malignant jaw tumour ablation. It has several advantages over other bones, including being the longest bone with lengths up to 25 cm, having bicortical structures that can support osseointegrated dental implants, having a large calibre and long vascular pedicles which promote easier anastomosis, and having thin and pliable skin paddles as well as available muscular cuffs around the fibula which can be used for reconstructing the various soft tissue defects. The morbidity at the donor site is also low and the operation time is reduced because of a two-team approach.

Taylor et al., in 1975, were the first to report successful transfers of the vascularized fibular bone graft for reconstructing fractures of the lower extremities. Hidalgo, in 1989, reported the first mandibular reconstruction using a vascularized fibula free flap. The complications of fibular bone harvesting have been reported and include great-toe contracture, motor weakness, sensory deficit, ankle pain, ankle instability, and compartment syndrome.

Although several studies regarding donor-site morbidity after fibula free flap transfer have been published, of which the majority have reported low donor-site morbidity, the evaluation methods have varied. Evaluation of donor-site morbidity after harvesting of fibular bone consists of subjective and objective evaluation. As the subjective evaluation depends on the patient, it can be performed using questionnaires on donor-site symptoms. The point evaluation system (PES) developed by Enneking et al. and modified by Bodde et al. has been used widely for subjective evaluation after fibulectomy. However, the scoring system uses the ordinal scale and qualitative data. The visual analogue scale (VAS) has been used most widely for the assessment of pain, but it is also used for other health-related symptoms such as psychometric evaluation, anxiety, mood, and quality of life. VAS uses the ratio scale and quantitative data, which can be used for the analysis of correlation coefficients with other continuous variables. Objective evaluations depend on examiners or equipment and include range of motion (ROM), strength of muscle, Kitaoka’s ankle–hind foot score, gait analysis, a balance test, and radiographic analysis. Previous studies found that the type of fibula flap harvesting (osseous or osteocutaneous) and morbid obesity could be risk factors that influence donor-site morbidity after free fibula transfer.

The aims of this study were: (1) to compare the VAS with the PES in the subjective evaluation of donor-site morbidity after fibula free flap transfer for oral and maxillofacial reconstruction; (2) to compare the functional outcomes and related factors of fibula free flap donor-site morbidity between patients with a normal body mass index (BMI) and those with a high BMI, and between skin paddle harvesting and no skin paddle harvesting; and (3) to determine the correlation between parameters of functional outcomes and other related factors.

Materials and methods

This cross-sectional analytical study included 17 consecutive patients who underwent a unilateral vascularized fibula free flap transfer for oral and maxillofacial reconstruction during the years 2009–2012. The study was approved by the research ethics committee. All patients gave informed consent to participate in the study. Inclusion criteria were patients who underwent fibular harvesting by a single surgeon between 4 and 24 months prior to being interviewed and who could return to the oral surgery clinic after invitation. Patients with a history of stroke, psychological disease, peripheral vascular disease, hip replacement, leg trauma, and diabetes were excluded from the study.

For all patients, the fibula was harvested via the lateral approach, in accordance with Gilbert, with the use of a tourniquet. After careful soft tissue dissection, the fibula was harvested with a small cuff of tibialis posterior and flexor hallucis longus. The skin paddle attached to its perforator was couple harvested with the fibula for soft tissue reconstruction or fibula flap monitoring in 12 cases. An 8-cm stump of distal fibula and a 6-cm stump of proximal fibula were preserved. A vacuum drain was inserted before wound closure. The skin of the fibular donor-site was closed primarily, except for one patient who required a split thickness skin graft. A slightly firm elastic bandage was wrapped around the donor leg.

In the first 3 days postoperatively, the patients were controlled in a neutral head position and were allowed to start early rehabilitation by movement of the knee, ankle, and toes on the bed, especially after the first 24 h. The total volume of liquid in the drainage bottle at the donor-site was measured by a single nurse. All patients were allowed to start non-weight-bearing exercises on postoperative days 5–7, or as early as they could tolerate. Demographic data such as gender, age, race, religion, and subjective self-assessments of functional outcomes were collected using a structured questionnaire. Preoperative data (BMI, underlying diseases, heavy smoking), intraoperative data (tourniquet time and pressure, area of skin paddle, length of harvested fibula bone), and postoperative data (total volume of liquid from the vacuum drain at the donor site, onset of walking start day, donor-site complications) were collected from the medical records. BMI was classified using the World Health Organization (WHO) BMI classification of overweight and obesity. The patients were classified into two groups: normal BMI (<23 kg/m 2 ) and high BMI (≥23 kg/m 2 ). Additionally, the patients who underwent fibular harvesting with a skin paddle were classified as the skin paddle group, and the remaining patients were the non-skin paddle group.

Before doing the VAS evaluation, all patients were standardized regarding the collection of VAS data. The subjective evaluation of functional outcomes was done using a VAS 10 cm in length for the following items: pain, paresthesia, walking ability, ability to perform daily activities, gait alteration, and cosmetic appearance. A reverse VAS (10 to 0) was used for the evaluation of pain, paresthesia, and gait alteration. At 20 min after completing the VAS, patients were asked to give a verbal categorical rating of the PES described by Bodde et al. The average VAS score for each patient was calculated and classified into four levels of severity for donor-site morbidity ( Table 1 ), which was modified from the pain-intensity categorization, and compared with the PES score. Overall satisfaction with the donor-site surgery was also assessed by VAS but not included in the total VAS score.

Table 1
Level of donor-site morbidity after fibula free flap transfer by VAS and PES.
Donor-site morbidity VAS score PES score
None 10 20
Low 7–9.9 13–19
Intermediate 4–6.9 6–12
Major 0–3.9 0–5

VAS, visual analogue scale; PES, point evaluation system.

Data were analyzed with descriptive statistics. Fisher’s exact test was used to compare categorical variables; the Student’s t -test was used to compare continuous variables. Comparison of VAS and PES scores, as well as the correlation between other continuous variables, was tested with Pearson’s coefficient of correlation. Statistical significance was set at P < 0.05.

Results

From a total of 17 consecutive patients, 15 patients met the inclusion criteria. Of these, nine were female and six were male, with an average age of 39.7 ± 17.0 years (range 17–65 years). All patients were of Thai nationality and the majority were Buddhists. The average time since the operation was 11.8 ± 6.4 months (range 5–23 months). One patient had controlled hyperthyroidism and another had controlled hypertension. One patient was a heavy smoker. The average BMI was 24.3 ± 5.3 kg/m 2 (range 18.2–39.4 kg/m 2 ). There were six patients who were classified as overweight, two who were classified as obese, and one who was classified as underweight. The average harvested fibular length was 15.0 ± 3.7 cm (range 7–21 cm). Other intraoperative and postoperative data are shown in Table 2 .

Table 2
VAS score for each parameter, intraoperative and postoperative data, and comparisons of the skin paddle group versus the non-skin paddle group, and patients with a normal BMI versus patients with a high BMI.
Parameters All ( n = 15) Skin paddle group ( n = 10) Non-skin paddle group ( n = 5) P -value Normal BMI group ( n = 7) High BMI group ( n = 8) P -value
VAS
Pain 9.0 ± 0.7 9.0 ± 0.8 9.1 ± 0.6 0.86 9.2 ± 0.5 8.9 ± 0.8 0.44
Paresthesia 9.0 ± 0.9 9.0 ± 0.6 9.0 ± 1.4 0.96 9.4 ± 0.6 8.7 ± 1.0 0.27
Walking ability 8.6 ± 0.5 8.5 ± 0.5 8.9 ± 0.4 0.15 8.7 ± 0.3 8.5 ± 0.7 0.47
Daily activity 8.9 ± 0.7 9.0 ± 0.6 8.8 ± 0.8 0.55 8.8 ± 0.8 9.0 ± 0.6 0.59
Gait alteration 8.2 ± 0.9 8.2 ± 0.7 8.3 ± 1.3 0.98 8.6 ± 0.9 7.9 ± 0.8 0.14
Cosmetic appearance 7.3 ± 1.9 7.0 ± 2.0 8.0 ± 1.7 0.33 7.8 ± 1.7 6.9 ± 2.0 0.38
Average VAS score 8.5 ± 0.6 8.5 ± 0.6 8.7 ± 0.7 0.53 8.8 ± 0.4 8.3 ± 0.7 0.19
Satisfaction 9.1 ± 0.5 8.9 ± 0.4 9.4 ± 0.4 0.03 a 9.2 ± 0.5 9.0 ± 0.4 0.33
Average PES score 15.0 ± 2.3 14.4 ± 2.6 16.2 ± 0.8 0.15 15.7 ± 2.0 14.4 ± 2.5 0.27
Tourniquet time (min) 131.7 ± 18.7 139.5 ± 15.4 116.0 ± 15.2 0.02 a 129.3 ± 9.3 133.8 ± 24.8 0.66
Tourniquet pressure (mmHg) 275.3 ± 31.6 279.0 ± 36.0 268.0 ± 21.7 0.55 272.9 ± 20.6 277.5 ± 40.3 0.79
Drainage volume (ml) 52.3 ± 37.7 43.2 ± 31.6 70.4 ± 45.8 0.20 58.9 ± 31.3 46.5 ± 43.8 0.55
Onset of walking (day) 5.9 ± 0.9 6.0 ± 0.8 5.8 ± 1.1 0.70 5.9 ± 0.9 6.0 ± 0.9 0.77
VAS, visual analogue scale; BMI, body mass index; PES, point evaluation system.

a Significant difference at P < 0.05.

The average VAS score was 8.5 ± 0.6 (range 7.2–9.2) and the average satisfaction with surgery score was 9.1 ± 0.5. The average VAS scores for the functional outcomes are shown in Table 2 . Cosmetic appearance was rated the lowest.

Table 3 shows the distribution of patients by PES parameters. The average PES score was 15.0 ± 2.3 (range 9–18). Donor-site morbidity after fibula free flap transfer was low in all patients for ratings by VAS, while ratings by PES showed low morbidity in 14 cases, but intermediate donor-site morbidity in one case. In addition, this study showed a significant positive correlation between the average VAS and PES scores ( r = 0.63, P = 0.01) ( Fig. 1 ).

Table 3
Point evaluation system (PES) ( n = 15).
Parameters of PES No. (%)
Pain
4 None 5 (33.3)
3 Mild (occasional, not intense) 9 (60.0)
2 Intermediate (occasional, intense) 1 (6.7)
1 Moderate (frequent, intense) 0 (0)
0 Severe (continuous, intense) 0 (0)
Walking ability
4 Unlimited (same as preoperative) 5 (33.3)
3 Intermediate (restriction in running) 8 (53.3)
2 Minor limitation (restriction on uneven terrain/uphill/stairs) 2 (13.3)
1 Major limitation (limited walking distance) 0 (0)
0 Not independently (occasional use of supports) 0 (0)
Restriction in activities
4 No disability 11 (73.3)
2 Minor disability (recreational restriction) 4 (26.7)
0 Major disability (restriction in daily activities) 0 (0)
Gait alteration
4 None 2 (13.3)
2 Minor (cosmetic alteration only) 13 (86.7)
0 Major (cosmetic and functional deficits) 0 (0)
Cosmetic appearance
4 Excellent 3 (20.0)
3 Good 7 (46.7)
2 Moderate 4 (26.7)
1 Intermediate 1 (6.7)
0 Bad 0 (0)
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Jan 24, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Donor-site morbidity after fibula free flap transfer: a comparison of subjective evaluation using a visual analogue scale and point evaluation system
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