The Dangle Study

Within the field of plastic surgery free tissue transfer is common practice. In
knee and lower leg defects due to trauma, oncological resection or chronic
infection adequate soft tissue coverage of bony structures is imminent. In case
of insufficient bony coverage a muscle or fasciocutaneous (skin and fat) free
tissue transplantation is performed. This is a microsurgical operation in which
a part of the body is transplanted to the defect. However, there is a great
diversity in the postoperative care for patients with a lower leg
reconstructions. The frequency and way of post-operative monitoring, wrapping
of the lower leg, total hospital stay, and the gradual increase of
gravitational forces on the free flap (dangling) are all critical protocols in
the postoperative care. Although, there is internationally no evidence based
consensus supporting the use of some of these protocols. With this randomized
controlled trial we would like to further investigate the need for dangling
protocols in these patients.
Worldwide there are multiple variations of dangling protocols. The starting
point, frequency, and duration of dependency vary widely; where some start the
dangling protocol as early as on the second postoperative day, others wait
until the fourth postoperative week (1-3). The remainders report to not use
dangling as a standard procedure at all (1), or only in selected cases (2).
When applied, the dangling sessions are prescribed once up to six or more times
a day, with a duration ranging from one up to 21 minutes per session. In
general the dangling protocol is performed in a hospital setting. Consequently,
patient discharge plans are highly variable ranging from discharge at
postoperative day four (when no dangling protocol is applied) to discharge in
postoperative week three (3), with higher medical costs and patient discomfort
as a result.
The best available evidence concerning an early start of the dangling procedure
comes from the articles of Jokuszies et al. (2013) (4) and Neubert et al.
(2015) (5). These are the only two known randomized controlled trials
available. They show that the combined wrapping and dangling procedure can
safely be started at postoperative day three, in patients treated with a
variety of free flaps. However it must be noted that the patients included in
this study are for the most part the same group of patients. Furthermore, the
number of patients in these studies were small: 31 and 49, for Jokuszies and
Neubert respectively (4-5), resulting in an underpowered study. A larger
randomized controlled trial is necessary to be able to amend the post-operative
care in clinical settings.
Kolbenschlag et al. conducted a prospective cohort study and used the same
dangling schedule (6). However, they did not start their dangling procedure
until postoperative day 6 and furthermore, they differentiated between the
different types of free flaps and medical conditions of patients.
Since there is limited evidence available in the literature supporting a
dangling protocol further research is required.

Primary objective parameter: to assess whether a no dangling protocol is
non-inferior to a dangling protocol in terms of proportion of patients who
experienced partial flaps loss which did not require another free lap procedure
at six months after surgery. We defined complete flap necrosis, partial flap
necrosis (if a revision surgery with a second free flap is necessary) and lung
embolia as major complications. Screening for lung embolia will only be
performed if there is a clinical suspection for a lung embolia. Partial flap
loss is defined as minor if no secondary free flap is needed or major if a
secondary free flap was needed. Wound dehiscence, wound infection, failure of
skin graft take on the free flap, and hematoma for which a surgical exploration
was needed were defined as the minor complications.

Secondary objective parameters:
- We hypothesize that there will be no difference in major complications at 6
months.
- We would like to objectify the gaseous changes within the free flap during
the dangling protocol in a selective group of patients.
- We will measure the physical functions at 3 and 6 months, 1 year, 1,5 years
and 2 years with the PROMIS, EQ-5D and VAS-score questionnaires.
- We hypothesize that there is no difference in the number of patients
experiencing one or more minor complications at three and six months post
operative.
- Investigate if there is a difference in the length of hospital stay between
the two groups.
- Investigate infection rates and osseous union rates with a follow up of two
years based on the patients* medical files.

The design of this study is a randomized controlled multicenter trial. The
study will take place in three Dutch hospitals: UMC Utrecht, Erasmus MC
Rotterdam and UMC Groningen. The study will end when 130 patients are included
with a maximum of three years. Within this study there will be two patient
groups. The patients will be randomized by a computer system to group A or B.
Patients in group A will start at postoperative day 7 with the dangling
protocol. Patients in group B are allowed to dangle for an unlimited time
starting at postoperative day 7. Blood tests will be performed in all patients
randomized in group A at the UMC Utrecht. All patients will be invited for two
short (PROMIS, EQ-5D and VAS) online questionnaires at 3 and 6 months, 1 year,
1,5 years and 2 years post operative.




*

- No dangling protocol
- Patients randomized in group A at the UMC Utrecht will undergo blood tests
with the use of a Point Of Care Testing (POCT) device. Point of Care Testing is
a technique that only needs a drop of blood and subsequently analyze this drop
of blood for pO2, pCo2 and PH levels. This test will not influence the overall
result of the study. The test is performed to monitor the gaseous changes
within the free flap during dangling. Within the UMC Utrecht this a commonly
performed test to monitor patients during anesthesia.

Based on the current literature there are no known increased risks involved
with the participation in this study. The hypostasised beneficial effect is
that patients in group B might have a shorter hospital stay. Patients
randomised to group A in the UMC Utrecht will undergo blood tests during the
dangling protocol. All patients will be invited to fill out two short online
questionnaires at 3 and 6 months, 1 year, 1,5 years and 2 years postoperative.
The estimated total time needed for filling out these questionnaires is 25
minutes.