Keywords
trapezius flap - cervical spine - thoracic spine
Introduction
Wound complications following spinal and cranial surgeries are uncommon.[1] However, factors such as surgical site infection, skin infiltration with tumor,
and radiotherapy may lead to the destruction of local tissue and wound gaping. Though
many of the cases can be managed with local wound care and skin grafting/local flaps,
in some cases, soft tissue loss is significant. Local flap tissue is often inadequate
to fill the three-dimensional soft tissue defects. The situation is more complicated
when an implant is exposed in the wound bed.
Free flaps are generally preferred in the reconstructive ladder due to their versatility
and reliability.[2] Large soft tissues can be resurfaced with relatively less donor-site morbidity.
However, it requires an extended duration of surgery, microsurgical expertise, and
risk of total flap loss. Trapezius myocutaneous or muscle-only flap is an excellent
regional option for resurfacing soft tissue defects over the cervico-occipital and
complex posterior scalp regions.
Our study aims to share our experience with trapezius flap for the reconstruction
of complex cervico-occipital and thoracic soft tissue defects.
Materials and Methods
A retrospective analysis of six patients aged over 10 years who underwent trapezius
flap from January 2016 to May 2019 was performed. Patient’s demographic data, the
indication of surgery, complications, and outcomes were analyzed and tabulated ([Table 1]).
Table 1
Details of the patients and flaps performed
|
Case
|
Diagnosis
|
Location of defect
|
Structure exposed
|
Flap size (cm)
|
Flap
|
Outcome
|
|
Abbreviation: LTMIF, Lower trapezius myocutaneous island flap.
|
|
1
|
Cervical implant exposure following resection of the craniovertebral junction anomaly
|
Occipitocervical region
|
Cervical spine
|
10 × 6
|
Right LTMIF
|
100% flap survival
|
|
2
|
Cervical implant exposure following resection of a C3–C4 spinal intradural extramedullary
meningioma
|
Occipitocervical region
|
Cervical vertebra
|
12 × 9
|
Right LTMIF
|
100% flap survival
|
|
3
|
Implant exposure following correction of kyphoscoliosis
|
Upper thoracic region
|
Thoracic spinal implant
|
8 × 4
|
Right trapezius turnover flap
|
100% flap survival
|
|
4
|
Full-thickness scalp and parieto-occipital calvarial defect following excision of
a tumor involving the scalp and calvarium
|
Parieto-occipital region
|
PMMA prosthesis for calvarial defects
|
17 × 10
|
Right LTMIF
|
Minor wound dehiscence leading to implant exposure
|
|
5
|
Rhabdomyosarcoma over the nape of the neck
|
Lower neck and upper thorax
|
Lower cervical and upper thoracic spinous processes
|
8 × 5
|
Right trapezius turnover flap and skin graft
|
Partial skin graft loss
|
|
6
|
Surgical site infection and wound dehiscence leading to thoracic spinal implant exposure
|
Thoracic spine
|
Thoracic spinal implant
|
15 × 8
30 x 8
|
Left trapezius myocutaneous V-Y advancement, right trapezius myocutaneous bipedicled
flap in addition to latissimus dorsi flap
|
100% flap survival
|
Surgical Technique
The anatomy of the trapezius muscle is well described.[3] We prefer the prone position for the ease of dissection and inset. The outline of
the trapezius muscle is marked between the external occipital protuberance superiorly,
the spinous process of the 12th thoracic vertebra inferiorly, the middorsal line medially,
and a line connecting the acromion to the spinous process of the 12th thoracic vertebra
laterally, as shown in [Fig. 1]. The medial border and the tip of the scapula are also marked.
Fig. 1 (A) Image showing important landmarks for trapezius myocutaneous flap: external occipital
protuberance, C7 and T12 spinous process. (B) Structures beneath the trapezius muscle. D, deltoid muscle; DSA, dorsal scapular
artery; LD, latissimus dorsi muscle; LS, levator scapulae; RM, rhomboid minor; RMa,
rhomboid major; S, scapula; T, trapezius muscle; TCA, transverse cervical artery (it
is embedded in the ventral surface of the trapezius muscle).
-
Lower trapezius myocutaneous island flap (LTMIF
): this flap was most often preferred for cervico-occipital defects. A template of
the defect was made and planned in reverse to design the skin territory over the trapezius
muscle. In a traditional LTMIF (based on the transverse cervical artery), a vertical
orientation of the skin paddle is preferred. The skin paddle was designed over the
muscle, and if the skin paddle crosses the muscle border, the crossed portion is considered
as a random pattern flap (length-to-breadth ratio of 1:1). The pivot point is between
the scapula and the midline at the level of the acromion process. However, when a
large flap is required, a significant portion of the flap is designed inferior to
T12. The incision is preferred at the lateral border of the skin paddle to ensure
appropriate identification and preservation of the trapezius muscle with the skin
paddle. The trapezius muscle is just beneath the fascia over the back and the muscle
fibers are longitudinal in orientation, whereas rhomboids are underneath the trapezius
muscle and horizontal in orientation. Once it was assured, the trapezius muscle was
dissected all around, and the skin incision was extended superiorly two fingerbreadths
lateral to the spinous processes. The trapezius muscle was dissected from the medial
to lateral direction as we approach superiorly to the neck to visualize and include
the transverse cervical vessels. As the dissection proceeds from the inferior to superior
direction, rhomboid major and minor have to be identified and preserved. There is
a difference of opinion regarding the inclusion of dorsal scapular vessels in large
trapezius flaps, which is described in detail in the Discussion section. We have not
included them in any of our patients. Inclusion of dorsal scapular vessels required
intramuscular dissection through the rhomboids. The reach of the flap can be increased
by islanding the myocutaneous flap and dissecting the transverse cervical vessels
until its origin in the posterior triangle of the neck. Once the flap inset was made,
the donor site was closed undercover a suction drain. Postoperatively patient is nursed
in the lateral/prone position for 2 weeks.
-
Turn over flap: this is a muscle-only flap. The flap is harvested by extending the preexisting cervicothoracic
wound. The inferior half of the muscle flap is exposed after skin, and subcutaneous
tissue is elevated. The muscle is dissected from the inferior to superior and the
lateral to medial direction, as described previously, to preserve the descending branch
of transverse cervical vessels. The spinal attachments of the trapezius muscle are
released and is transferred to the defect by turning the inferior portion into the
midline defect. This flap can also be based on the intercostal vessels after dividing
the transverse cervical vessels.
-
V-Y advancement flap: this flap is similar to the LTMIF. The skin paddle is designed over the trapezius
muscle and the trapezius divided from its attachments while preserving the transverse
cervical vessels. In this manner, this flap is useful to cover the soft tissue defects
over the upper thoracic region.
-
Bipedicled trapezius myocutaneous flap: this flap is similar to the LTMIF. The flap is based on transverse cervical vessels,
and the skin in undivided superiorly and inferiorly as in traditional bipedicled flap.
The flap is harvested in a bucket-handle fashion and can cover the entire thoracic
spine.
Results
Six patients (three males and three females) underwent seven reconstruction using
trapezius flaps (patient 6 underwent reconstruction using a bilateral trapezius flap).
The trapezius flap was used to resurface the parieto-occipital (n = 2), cervico-occipital (n = 2), cervicothoracic (n = 1), and thoracic (n = 1) regions. The details of the patients are tabulated in [Table 1]. One patient (patient 4) had developed postoperative wound dehiscence leading to
exposure of the calvarial bone graft. This patient had a fungating calvarial tumor
and poor general status and was planned for a flap advancement/implant revision subsequently.
Another patient (patient 5) had partial skin graft loss, which healed by secondary
intention. Rest of the patients had uncomplicated recovery and stable wound coverage.
The mean flap surface area was 110 cm2 (range: 32–240 cm2). In five of six patients, donor site was closed primarily, and one patient required
skin grafting and latissimus dorsi V-Y advancement flap to cover the flap donor site.
Two patients (patients 3 and 5) underwent muscle-only flap and skin graft covering.
None of the patients had donor-site seroma or wound dehiscence. Mild shoulder weakness
was noted in two patients, which gradually improved with physiotherapy.
Clinical Examples
Patient 2
A 20-year-old female patient underwent excision of a C3–C4 spinal intradural extrameningeal
meningioma and C2–C5 laminoplasty by the neurosurgeons. Postoperatively, she developed
wound dehiscence leading to a wound of 12 × 9 cm over the right cervical-occipital
region. The implant was exposed, and the cervical spine was exposed at the floor of
the ulcer. The patient underwent debridement of the wound followed by reconstruction
with right sided LTMIF. The Flap settled well and yielded a good outcome ([Fig. 2]).
Fig. 2 Image showing (A) soft tissue defect over the right occipitocervical region, (B) flap marking, (C) lateral spine X-ray to show the laminoplasty implants, (D) harvested lower trapezius myocutaneous flap (dashed lines indicate the muscle outline), (E) flap inset and donor-site wound closure, and (F) well-settled flap. RM, rhomboid minor; S, scapula; T, trapezius muscle.
Patient 4
A 30-year-old female presented with fungating calvarial tumor with intracranial extension.
The neurosurgeons performed a palliative resection of the tumor. This resulted in
a composite defect of scalp and calvarium in the parieto-occipital region. The calvarial
defect was reconstructed with a polymethyl methacrylate (PMMA) prosthesis. The scalp
defect was17 × 10 cm. The topmost point of the defect was the vertex. Right LTMIF
was used to cover the defect. The patient had wound dehiscence leading to the exposure
of the PMMA implant. She requires flap advancement or implant revision subsequently
([Fig. 3]).
Fig. 3 Image showing (A,B) fungating calvarial tumor, (C) MRI scan showing intracranial extension, (D) duraplasty covered with adrenaline soaked gauze, (E) the calvarium reconstructed with PMMA implant and in situ marking for the right
trapezius myocutaneous flap, (F) flap inset, and (G) well-settled flap with minor wound dehiscence. PMMA, polymethyl methacrylate.
Patient 5
A 15-year-old male patient underwent wide local excision of the rhabdomyosarcoma of
the lower cervical and upper thoracic regions, leading to exposure of the spinous
processes. He underwent reconstruction using turnover trapezius muscle flap from the
right side and skin grafting. The muscle flap was supplied by the intercostal vessels.
Postoperatively, there was minimal skin graft loss, which healed with local wound
care ([Fig. 4]).
Fig. 4 Image showing (A) rhabdomyosarcoma over the lower cervical and upper thoracic regions, (B) right trapezius muscle flap covering the spinous processes, (C) skin graft over the muscle flap and adjacent soft tissue defect, and (D) well-settled wound.
Patient 6
A 10-year-old child presented with surgical site infection and soft tissue loss following
kyphoscoliosis correction and spinal instrumentation. After debridement, the wound
size was 25 × 10 cm with exposed thoracic spine and spinal instrumentation. Paraspinal
muscles were sloughed off and unavailable for reuse. Though a free flap would be an
ideal choice, it was kept as a last resort. In [Fig. 5C], the skin markings show the outline of the trapezius muscle, and the dotted line
on the right side show the markings of the bipedicled flap. The trapezius muscle was
included in the bipedicled flap till T12, and beyond this, the flap was undermined
completely. We noticed that the flap could be advanced 8 cm medially at the center
point ([Fig. 5D]). On the left side, a trapezius myocutaneous flap was designed in a V-Y fashion,
and the muscle was dissected free on the lower, medial, and lateral sides, retaining
its blood supply from the upper aspect. The secondary defect that was created by bipedicled
flap was covered with a latissimus dorsi myocutaneous V-Y advancement flap. The donor-site
defect in the inferior aspect was covered with a skin graft ([Fig. 5G]). Patient’s wounds healed completely ([Fig. 5H]).
Fig. 5 Image showing (A) ulcer over the back with slough exposed thoracic spinal implant, (B) spinal implant and thoraco-lumbar spine, (C) markings of the trapezius flap on both sides, (D) left trapezius myocutaneous V-Y advancement flap and right bipedicled trapezius
myocutaneous flap, (E) advancement of left trapezius myocutaneous V-Y flap, (F) advancement of the right bipedicled trapezius myocutaneous flap, (G) final wound closure after closing the secondary defect with V-Y latissimus dorsi
flap on the right side, and (H) well-settled flaps and skin graft.
Discussion
Wound complications following complex cervico-occipital surgeries are rare and pose
a serious reconstructive challenge. This is often complicated by exposure of the underlying
bone, dura, and hardware. Compromised blood supply at the incision site is one of
the common causes for the wound breakdown.[1]
Secondary intention and split-thickness skin grafting for wound healing are good options
for small defects without an exposure of critical structures. In case of large three-dimensional
wounds, exposed implants used for the stabilization of craniovertebral junction/cervicothoracic
spine, and exposed bone and intracranial structures, flap cover is mandatory. Though
local scalp flap options are available, they are useful in small tissue defects only
due to their restricted tissue mobility and limited thickness.[4] Large three-dimensional defects usually require bulky distant flaps or free flaps
to provide adequately vascularized soft tissue. Free tissue transfer is a versatile
option for the coverage of these defects. However, morbidity might be increased.[5] Trapezius flap being a regional option is a simpler alternative.
According to Haas and Weiglein,[6] trapezius flaps can be harvested in four different ways ([Table 2]).
Table 2
Various types of trapezius flaps
|
Type
|
Blood supply
|
Muscle
|
Skin paddle orientationa
|
Remarks
|
|
aOther skin paddle designs include a V-Y shape to cover the middle and upper thoracic
spine; a bipedicled design is useful for the coverage of long longitudinal narrow
defects in the thoracic spine. Both of them are based on the transverse cervical vessels.
Source: adapted from Haas and Weiglein6.
|
|
1
|
Occipital vessels
|
Superior descending muscle fibers
|
Transverse
|
Rarely used
|
|
2
|
Ascending and descending branches of transverse cervical vessels
|
Middle transverse fibers
|
Transverse or vertical
|
Most commonly used
|
|
3
|
Dorsal scapular vessels
|
Inferior ascending fibers
|
Vertical
|
The skin island should overlie the distal border of the trapezius muscle by at least
one-third of its diameter
|
|
4
|
Intercostal vessels
|
Ascending muscle fibers
|
Turn over muscle flap (no skin paddle)
|
Most commonly used for the middle and upper thoracic spine
|
In our series, all of the myocutaneous flaps were vertical skin paddle trapezius flaps
(LTMIF) when utilized for posterior scalp and cervico-occipital region (type 2) based
on the descending branch of the transverse cervical vessels. Dorsal scapular vessels
were not included in any of the patients. In all of the LTMIF patients, the lowermost
portion of the flap crossed the tip of the scapula by around <5 cm. It was ensured
that more than two-thirds of the skin paddle of the flap was overlying the trapezius
muscle. It is well known that the dorsal scapular vessels supply the lower portion
of the trapezius muscle and skin predominantly. Skin paddle as low as 10 to 13 cm
below the scapula tip has been described (extended vertical flap design).[7] Urken et al[8] opined that the lower extent of the flap should not be >5 cm below the tip of the
scapula when the flap is based exclusively on the transverse cervical vessels. Uğurlu
et al[7] described that the lower border of the skin paddle could be harvested as low as
24 cm below the tip of the scapula in spite of transecting the dorsal scapular vessels.
Can et al included both the transverse cervical vessels and dorsal scapular vessels
in the flap and achieved good results.[9] We also feel that the exclusion of dorsal scapular vessels in the flap design would
not affect the flap survival even in the lower vertical trapezius flap.
The mean flap surface area of the largest trapezius flap described was of 504 cm2.[10] Preservation of the superior fibers of the trapezius is essential to preserve the
function of the muscle. The reach of the flap can be increased by dividing the superior
fibers and dissecting the transverse cervical vessels until the origin. However, this
can be avoided by using an extended vertical trapezius flap described by Uğurlu et
al.[7] We did not need to cut the superior fibers of the trapezius muscle in any of our
patients.
Pedicled latissimus dorsi muscle flap is an option for the coverage of the occipital
region. However, it requires extensive dissection and division of the insertion from
the humerus and skeletonization of the pedicle.[11] Trapezius flap is a reliable option for the coverage of the upper thoracic spine,[12] whereas latissimus dorsi muscle flap is used for soft tissue defects over the thoracolumbar
and lumbar spine.
Flap survival rate was 100%, and wound gaping requiring resurgery was noted in one
(20%) patient. Can et al[9] reported that 16.3% of patients required resurgery due to flap-related complications.
Literature review shows that complications range from 0 to 57%.[9]
Trapezius flap was also described for the reconstruction of the oral cavity[13] and face.[8] The hairless skin suits better for these areas. A limitation of trapezius flap is
that it might be compromised in patients with prior neck dissection in which transverse
cervical vessels were ligated. Nonhair-bearing skin over the scalp could be a cosmetic
concern for some patients. Though uncommon, persistent pain and shoulder weakness
might be troublesome donor-site complications.
The limitations of the study are small sample size and shorter follow-up duration.
Conclusion
The trapezius flap is a reliable and good alternative option to free flaps for coverage
of complex cervical-occipital and upper thoracic soft tissue defects.
