Keywords maxilloalveolar resections - chimeric flaps - free anterolateral thigh flap - head
and neck cancer - head and neck reconstruction
Introduction
Head and neck malignancy is the most common site for cancer in India, constituting
25 to 30% of the cancer burden. Due to prevailing socioeconomic, educational, and
cultural conditions, patients often present to tertiary care centers with advanced
cancers.[1 ] The surgical resections of such advanced tumors often leave us with complex defects
that need to be addressed, considering their three-dimensional nature to provide the
best possible reconstruction.
In the case of maxilloalveolar resections, the integrity of the maxillary sinus is
often lost. Free flaps have been considered ideal for the reconstruction of such defects.
Care must be taken to ensure the sinus cavity is effectively obliterated while reconstructing
such defects. Otherwise, the constant outpouring of the maxillary secretions will
lead to poor wound healing, fistula formation, wound gape, and may even cause flap
loss. This would further result in an increased hospital stay, delay in adjuvant therapy,
and an unwarranted burden on the healthcare system.
Several methods, like using non-vascularized fat, the de-epithelialized paddle of
the flap, and musculocutaneous flaps, have been tried to achieve an adequate obliteration
of the maxillary sinus cavity and to avoid the complications associated, each with
its own limitations. Chimeric flaps have the advantage of providing the benefit of
two vascularized tissue subunits with independent freedom of movement, with the ease
of a single set of vascular anastomoses.[2 ]
In our tertiary care cancer center, we used to obliterate the maxillary sinus cavity
with either fat from the flap or its de-epithelialized end, till December 2021. We
observed a high complication rate in the form of excessive maxillary discharge from
the neck, wound infection and wound gape. These complications resulted in flap failures
too. Many patients had delay in wound healing, and needed secondary procedures like
debridements, resuturing, etc. either under local anesthesia (LA) or general anesthesia.
This whole scenario eventually resulted in an increased hospital stay. To ameliorate
this, we started routinely harvesting a chimeric vastus lateralis (VL) along with
the anterolateral thigh (ALT) flap to plug the maxillary sinus. In this study, we
present our experience, comparing the efficacy of using chimeric ALT flap with the
VL compared with only ALT in reconstructing cases of oral malignancy who underwent
a bialveolar resection, leaving the maxillary sinus open.
Materials and Methods
During the study period of March 2021 to July 2022, we performed 275 ALT flaps for
head and neck reconstruction for oral cancer. Of these, we selected all cases fitting
our inclusion criteria:
Age above 18 years
Patients undergoing surgery for the first time and as the first modality of treatment
Brown class IIb maxillectomy with or without mandibular defect.[3 ] If the mandibular defect was present, those with posterior segmental mandibulectomy
(Brown class Ic and class IIc mandibulectomy)[4 ] or marginal mandibulectomy, undergoing only soft tissue reconstruction, were included.
Exclusion criteria :
Recurrent cases, previously irradiated patients, patients who have undergone neoadjuvant
chemotherapy and previously operated patients for head and neck pathology.
Defects that required either two free flaps or a large free flap that required skin
grafting at the donor site were excluded.
The patients were divided into the ALT-only group and the chimeric group based on
the type of flap used for reconstruction. We started doing chimeric ALT as a routine
after December 2021. That's why we used control arm of ALT only group from March 2021
to December 2021 and case arm, that is, chimeric ALT group from December 2021 to July
2022. The 39 patients in the ALT-only group and 26 patients in the chimeric group
were matched based on age, comorbidities, size, and type of defect, and after matching
20 patients could be included in each arm.
A predesigned proforma was used to collect data from patient examinations and interviews,
hospital electronic medical records, and department case record forms. Data were tabulated
and analyzed with respect to the following:
-Intraoperative ease and adequacy of maxillary fill
-Postoperative secretions from the neck and suture lines
-Length of hospital stay
-Duration of adjuvant therapy
-Postoperative complications, which were tabulated using the modified Clavien-Dindo
Classification for free flaps in head and neck reconstruction.[5 ]
Surgical Technique
Preoperatively, the thigh perforators were marked, using an 8 MHz handheld Doppler
device, at the standard site, using a circle of 3 cm radius, centered on the mid-point
of the line joining the anterior superior iliac spine to the superolateral border
of the patella.
The reconstruction team began raising the flap, while the resection team resected
the primary tumor and dissected the neck nodes.
A linear exploratory primary incision was taken approximately 2.5cm medial to the
perforator marking, as this allows for proximal or distal extension, if needed, depending
on the perforator availability.
The perforators were identified and dissected in the standard manner until the pedicle
was dissected sufficiently. Care was taken to preserve the nerves to VL and rectus
femoris. When chimeric flap was harvested, the distal runoff to the VL muscle was
preserved, and the required chimeric muscle was harvested based on it.
The maxillary sinus mucosa was scooped out thoroughly in all cases. In the ALT-only
group, the fat from the flap or the de-epithelialized edge of the flap was used to
obliterate the maxillary sinus. In the chimeric group, the VL muscle was used as filler
for dead space obliteration in the maxillary sinus. The amount of muscle harvested
was according to need of the filler as per defect size measurements. The muscle was
hitched in the maxillary sinus with Vicryl 2/0 after drilling holes in maxillary wall
and to the surrounding tissue.
The microvascular anastomosis was done after the inset. We use 14 French suction drain
with single tube for all the cases. We placed the drain tube under the sternocleidomastoid
muscle.
Postoperative Protocol and Follow-Up
The flap was monitored clinically by pinprick every 2 hours for the first day and
every 6 hours for the next 5 days. We did not routinely prescribe anticoagulants or
blood thinners to the patients except as a part of deep venous thrombosis prophylaxis.
We try to express the neck secretions on daily basis and measure the amount of collection
as per the number of gauzes or gamjee pad soakage. If the discharge is serous and
reducing in quantity, we included it under minor discharge and a part of the normal
postoperative sequence. If the discharge is not reducing or is increasing trend or
there is change in character (like salivary/ mucoid/ purulent), we considered it as
a complication and dealt with accordingly.
As a routine, the patients were mobilized on the first postoperative day, oral liquids
were started on the fifth postoperative day, and discharge from in-hospital care was
given on the seventh postoperative day for all patients without any complications,
precluding the same. We remove drains, when drain output is less than 20 mL in 24 hours
for consecutive 2 days.
The patients were followed up in the plastic surgery outpatient department twice a
week for 2 weeks after discharge, once a fortnight for a month after and once in 3
months. As indicated, they were also followed up in the surgical, medical, and radiation
outpatient departments.
Results
Patient characteristics : 31 out of 40 patients were males (80% in the ALT-only arm and 75% in the chimeric
arm.) The mean age of the study population was 65 years, with the ALT-only group having
a mean of 64 years and the chimeric arm having a mean of 66 years. There was no significant
difference between the groups' patient characteristics or comorbidity profiles ([Table 1 ]).
Table 1
Patient characteristics
Characteristic
ALT only group
n = 20
No. of patients (%)
Chimeric group
n = 20
No. of patients (%)
Sex
Male
16 (80)
15 (75)
Age (years)
Median (range)
64 (32–76)
66 (30–73)
Medical comorbidities
Diabetes mellitus
5 (25)
4(20)
Hypertension
9(45)
6(30)
Cardiac disease
–
1(5)
Pulmonary disease
–
–
Morbid obesity
1(5)
2(10)
Underweight
1(5)
–
Tobacco use
18(80)
16(80)
Alcohol use
12(60)
10(50)
Abbreviation: ALT, anterolateral thigh.
While the resecting team was operating at the head end, simultaneous harvest was done
in all our patients. No significant difficulty was faced in the harvest of a chimeric
flap over the harvest of an ALT in any of our patients. The mean time to harvest completion
was comparable in both groups (75.5 minutes in the ALT group and 78 minutes in the
chimeric group).
Defects included Brown class IIb maxillectomy with or without mandibular defect, as
described in [Table 2 ]. Eight patients in the ALT-only group and seven in the chimeric group had skin defects
([Fig. 1B ]).
Table 2
Mandibular defect characteristics
Mandibular defect
ALT only group
n = 20
Chimeric group
n = 20
None
6
5
Marginal mandibulectomy
3
4
Brown class Ic
8
8
Brown class IIc
3
3
Abbreviation: ALT, anterolateral thigh.
Fig. 1 (A ) Preoperative photograph. Patient carcinoma of the right buccal mucosa involving
both jaws, with involvement of skin. (B ) Intraoperative picture of the defect postsurgical extirpation. The defect involves
both jaws, Brown class IIb maxillectomy with Brown class Ic mandibular defect, right
buccal mucosa, and skin. (C ) Harvested chimeric free anterolateral thigh skin paddle (white arrow) with vastus
lateralis muscle (black arrow) on a single vascular pedicle. (D ) Postoperative picture of the patient.
Primary closure of the donor site was achieved in all patients.
We compiled the complications in both groups and tabulated them using the modified
Clavien-Dindo classification for free flaps in head and neck reconstruction. The patients
in the chimeric group were found to have lesser complications causing deviation from
the routine postoperative course (p < 0.05, chi-squared test). The chimeric group also required fewer secondary procedures
with or without general anesthesia ([Table 3 ]).
Table 3
Modified Clavien-Dindo classification for complications
Grade
Definition
No. in ALT-only group
n = 20
No. in chimeric group
n = 20
I
Any deviation from the normal postoperative course WITHOUT the need for pharmacological
or surgical, endoscopic, or radiological treatment
3
2
II
Requiring pharmacological treatment (blood transfusions/TPN)
3
1
IIIa
Requiring surgical, endoscopic, or radiological intervention NOT under GA
1
2
IIIb
Requiring surgical, endoscopic, or radiological intervention under GA
3
–
IIIc
Partial/ total flap failure
2
–
IVa
Life-threatening complication—single organ failure
–
–
IVb
Life-threatening complication—multiorgan failure
–
–
Abbreviations: ALT, anterolateral thigh; GA, general anesthesia; TPN, total parenteral
nutrition.
Excessive secretions leading to neck collections and delay in discharge occurred in
three patients in the ALT-only group and in two patients in the chimeric group (grade
I).
Culture-positive neck wound infection occurred in three patients in the ALT-only group
and one patient in the chimeric group, requiring higher antibiotics (grade II).
One patient in the ALT-only group had to undergo resuturing of the neck wound under
LA due to the breaking down of the wound, while in the chimeric group, one patient
underwent wound wash and resuturing of the neck suture line under LA and one patient
underwent resuturing of the facial suture line (grade IIIa).
Three patients in the ALT-only group had grade IIIb complications, requiring general
anesthesia administration for management. Two of these patients underwent closure
of the orocutaneous fistula and neck wound wash, and one underwent neck wound wash
with secondary suturing.
One total flap failure due to venous thrombosis, requiring a second flap for reconstruction
on postoperative day 4 and one partial flap loss requiring debridement and reinset,
was found in the ALT-only group (grade IIIc).
On comparing the mean duration of hospital stay of patients in both the groups, the
mean was found to be 15.52 days, with the ALT-only group having a mean of 18.75 days,
while patients in the chimeric flap group had a mean duration of hospital stay to
be 12.3 days. There was a significant difference in the duration of hospital stay
between the two groups (p < 0.05, unpaired t -test). Further, we found that one patient from the ALT-only group had to be readmitted
for in-patient care due to a neck wound infection.
Following the histopathology report, adjuvant radiation was indicated in all the patients
in the study. In the chimeric group, all 20 patients received adjuvant radiation within
the optimum time window. In comparison, two patients in the ALT-only group did not,
as the wounds were not adequately healed and ready for radiation therapy within the
optimum time window. One of them defaulted from care (p > 0.05, Fisher's exact t -test) ([Table 4 ]).
Table 4
Postoperative characteristics
Characteristic
ALT only group
Chimeric group
Duration of postoperative hospital stay
Mean (days)
18.7
12.3
Range (days)
10–35
7–20
Successful and adequate adjuvant RT
Number of patients (%)
17(85)
20(100)
Abbreviations: ALT, anterolateral thigh; RT, radiotherapy.
All the donor sites were closed primarily. None of our patients had significant donor
site complications, and all healed well. No functional disability in walking and daily
routine activities was found in any group.
Discussion
In a country like India, where the oral cancer burden is high, and the age of presentation
is relatively younger, it is of utmost importance that the patients get the best possible
treatment with the shortest duration of hospital stay possible, an uneventful transition
to adjuvant therapy and an early return to a productive life. We face challenges in
achieving these goals because many patients present to tertiary centers with locally
advanced malignancies. The surgical resection of such tumors results in large, complex,
three-dimensional defects that require the reconstructive surgeon to have a thorough
knowledge of the available armamentarium, meticulous planning, and surgical skill
([Fig. 1B ]).
Brown class IIb maxillectomy leaves the maxillary sinus opened[3 ] and very often, despite meticulous scooping-out of the residual sinus mucosa, there
is continuous discharge that can be detrimental to the flap health, causing the patients
to undergo additional procedures, have a prolonged hospital stay, have a delay in
undergoing adjuvant radiation therapy, and even cause loss of the flap itself. Obliteration
of the sinus dead space is effective in controlling this secretion. Various tissues
have been used for this purpose. Nonvascularized fat or muscle has a high failure
rate with eventual necrosis and extrusion, adding to the problem.
When used, the distal de-epithelialized paddle of ALT poses difficulties because the
thick ALT paddle forms a significant bulk when it is folded, and the inset becomes
more difficult. This makes the patient more prone to develop orocutaneous fistulae,
and their associated morbidity.[6 ]
[7 ]
A musculocutaneous ALT, when used for this purpose, does aim to provide a vascularized
muscle to plug the dead space. Still, due to the restricted mobility of the distally
placed muscle with respect to the skin paddle, it is often difficult to direct the
muscle to fill the cavity effectively.[8 ]
A chimeric flap provides a suitable solution to the challenge of filling the sinus
dead space adequately, along with the mucosal defect reconstruction.
Chimeric flaps based on the lateral circumflex femoral artery (LCFA) system have been
well elaborated in literature and must be in the armamentarium of a reconstructive
surgeon.[9 ] A chimeric flap refers to different tissue subunits on separate vascular leashes
that naturally converge to a single vascular pedicle ([Fig. 1C ]). This gives each tissue component independent freedom of mobility, all with a single
set of anastomoses, leading to ease of inset, lesser stretch on the paddle, and better
approximation of the edges to provide a watertight seal. This facilitates better healing
and less morbidity.[10 ] There have been multiple studies wherein the principle of chimerism based on the
LCFA axis has been used to successfully reconstruct complex mandibular and mid-face
defects without additional donor morbidity.[11 ]
[12 ]
In the case of reconstruction done for oral malignancy, the adjuvant therapy that
completes the patient's treatment must be kept in mind. A poorly healing wound is
unfavorable, and the patient might lose the optimum time window to receive radiation.
Every attempt must be made to avoid wound and flap-related morbidity so that the cancer
therapy is completed on time and the chance of a recurrence is lowered. Undue delay
to adjuvant treatment due to additional procedures and flap loss, owing to the continued
maxillary sinus secretions can be prevented by using the principle of chimerism to
plug the sinus with vascularized VL muscle without any added donor morbidity or surgical
difficulty ([Fig. 2 ]).
Conclusion
Chimeric ALT with VL muscle is a reliable option for reconstructing complex defects,
especially with dead space cavities like the maxillary sinus.
Effective plugging of the maxillary sinus during the primary surgery results in decreased
hospital stay and less number of secondary procedures.
Fig. 2 Late postoperative, photograph of the same patient (at 1-year follow-up).
