Perforator Branch–based Dissection for Ultrathin Anterolateral Thigh Free Flap for Tongue Reconstruction: A Preliminary Report

Abstract

Background:

This study compared tongue reconstructions in hemiglossectomy patients using ultrathin free flaps with perforator branch–based dissection (PBD) versus conventional anterolateral thigh (ALT) subfascial free flaps. We aimed to evaluate the success rates and speech function outcomes of these techniques, focusing on managing flap thickness.

Methods:

A retrospective review of hemiglossectomy patients (2017–2023) was conducted, focusing on ultrathin subdermal perforator free flaps versus conventional ALT free flaps. Speech function, surgical details, and complications were assessed to compare outcomes. Speech intelligibility and articulation were analyzed using standardized tests.

Results:

Sixteen patients (mean age 49 [range 22–81] y) underwent tongue reconstruction with conventional or PBD ALT flaps. The PBD flap group had no debulking needs, whereas 3 conventional flap patients required it. Speech function analysis showed higher articulation (89.5% versus 80.5%) and intelligibility (100% versus 84.3%) in the PBD flap group.

Conclusions:

PBD for ultrathin ALT flaps in hemiglossectomy patients offers comparable functional outcomes to conventional ALT flaps, making PBD a viable alternative, despite the learning curve.

Takeaways

Question: Does perforator branch dissection (PBD) for ultrathin anterolateral thigh (ALT) free flaps improve functional outcomes in tongue reconstruction compared with conventional ALT flaps?

Findings: In this retrospective study of 16 hemiglossectomy patients, PBD ultrathin ALT flaps achieved comparable speech intelligibility and articulation to conventional ALT flaps, with no need for secondary debulking procedures in the PBD group. One flap failure occurred in the PBD group due to short pedicle length.

Meaning: PBD ultrathin ALT flaps provide effective tongue reconstruction with good speech outcomes and reduced secondary procedures, offering a viable alternative to conventional methods.

INTRODUCTION

Head and neck reconstructions are among the most challenging specialties in reconstructive surgery due to the complexity of restoring both shape and function.¹ Despite the success of various flap techniques, achieving optimal outcomes remains difficult. Historically, various local and distant flaps were used, but since 2000, free flap options have become the gold standard for these procedures.¹ More recently, perforator free flaps have emerged as the preferred choice for microsurgical head and neck reconstructions, particularly since 2010.^1–3

We are currently in an era dominated by the use of perforator free flaps.^2–4 However, the variability in skin thickness and texture among different donor sites and patients poses significant challenges. The bulkiness and thickness of perforator flaps are critical concerns because these reconstructions require precise 3-dimensional (3D) contouring for both facial resurfacing and intraoral mucosal lining.⁵ Surgeons often struggle to recreate intricate 3D anatomic structures with bulky flaps, and even perforator flaps can be problematic if they are too thick. This is particularly challenging in tongue reconstructions, where the shape significantly influences function. Thin flaps, which have been reported since the 1980s, provide better aesthetic outcomes and lower donor site morbidity.^6–8 Microdissection, which involves skeletonizing flap perforators, has been further refined by allowing for uniformly thin flaps through precise techniques under a microscope.⁹ However, the pursuit of thin, thickness-controlled perforator flaps introduces concerns regarding overall flap success.^5,10 Our approach to tongue reconstruction with perforator flaps focuses on managing thickness and bulk through 4 strategies: selecting the ideal donor site, performing intraoperative defatting procedures; using secondary debulking procedures, and modifying the flap elevation plane.

This study aims to compare the outcomes of tongue reconstructions in hemiglossectomy patients using ultrathin free flaps with microdissection versus conventional anterolateral thigh (ALT) subfascial free flaps. These 2 techniques were evaluated in terms of success rates and speech function outcomes.

MATERIALS AND METHODS

We conducted a retrospective review of patients who underwent head and neck reconstruction at a single center from 2017 to 2023. The focus was on ultrathin subdermal perforator free flaps, where the perforators were dissected above the superficial fascia to the subdermal layer. This study received institutional review board approval (no. 2023-0823).

Inclusion criteria comprised patients who underwent hemiglossectomy reconstruction with ALT free flaps and completed speech tests during a follow-up of 6 months or longer. Exclusion criteria were patients with facial reconstruction (for cancer, trauma, or vascular malformation), scalp reconstruction, oral reconstruction not involving the tongue, and patients without a follow-up of 6 months or longer, or speech function evaluations.

Data collected included diagnosis, flap size, type of reconstruction (perforator branch–based dissection [PBD] or conventional ALT), and demographics. Surgical details such as pedicle length, flap size, and the number of perforators were evaluated. Additionally, surgical complications, secondary procedures, and donor site complications were assessed. Speech function analyses focused on intelligibility and articulation. This study aimed to compare the outcomes of ultrathin subdermal perforator free flaps with conventional ALT free flaps regarding surgical success and speech function (Fig. 1).

Fig. 1.

Illustrations of the 2 surgical techniques used in this study.

Preoperatively, we check the locations of perforators with high-frequency ultrasound. In our practice, there are 2 methods to elevate ultrathin subdermal perforator free flaps. The first method involves elevating the traditional sub–deep fascia plane of the perforator flaps and then following the branches of the perforators between the deep fascia and subdermal plexus. The second method starts by first dissecting the perforator branches between the deep fascia and subdermal plexus, and then dissecting the main pedicles. (See Video [online], which displays the operative techniques of PBD with ultrathin free flap.)

Video 1. Operative techniques of perforator branch-based dissection with ultrathin free flap.

Download video file ^{(59.9MB, mp4)}

In both approaches, viewing the perforator flaps from the side allows surgeons to better identify multiple small branches of the perforators. We dissected these branches using microscissors and microforceps, along with bipolar coagulators from the side view. After dissection of the small branches, the remaining parts of the flaps were elevated using a monopolar Bovie while preserving the subdermal plexus.

Articulation and Intelligibility

All evaluations were documented by a speech therapist using video or audio recordings. The speech therapist assessed intelligibility using a 5-point rating scale: 0 (never understandable), 25 (difficult to understand), 50 (usually understandable), 75 (mostly understandable), and 100 (always understandable). To calculate consonant accuracy, the number of incorrectly pronounced phonemes was subtracted from 43, and the result was divided by 43 and then multiplied by 100. The percentage of consonants correct (PCC) was calculated from the following formula: PCC = (43 – number of errors)/43 × 100.

RESULTS

A total of 16 patients with a mean age of 49 (range 22–81) years were included in this study; the mean follow-up duration was 12.3 (range 6–30) months. TNM (tumor, node, metastasis) staging and other demographic details are summarized in Table 1. No preoperative radiotherapy was performed; however, postoperatively, 4 patients in the conventional group and 3 in the microdissection group received radiotherapy. There were no significant differences in age, sex distribution, smoking history, or postoperative radiation therapy between the conventional and PBD groups. The mean flap size was 64.53 (range 32–175) cm², and the mean pedicle length was 9.2 (range 5–14) cm. Eleven flaps were elevated based on the descending branch of the lateral circumflex femoral artery, and 5 flaps were based on the transverse branch of the lateral circumflex femoral artery. For recipient vessels, the superior thyroid artery was used in 12 flaps, and the branch of the internal jugular vein was used in 8 cases.

Table 1.

Demographics of the Study: Demographic and Clinical Characteristics of Patients in the Conventional and Microdissection (PBD) Groups

	Conventional	PBD
Number	8	8
Age, y	50.1 (range, 22–64)	51.3 (range, 27–81)
Sex	M 6; W 2	M 5; W 3
Smoking	1	5
Radiation therapy	4	3
pTNM staging
T
pT0
pT1
pT2	4	6
pT3	2	2
pT4a	2
N
pN0	4	6
pN1		1
pN2	3
pN3	1	1
M
pM0	8	8
pM1
Follow-up	12.8 (range, 6–24)	11.6 (range, 7–18)

Among the patients, 8 underwent conventional ALT flap elevation, and the other 8 had ultrathin ALT flaps with PBD. In the conventional group, 3 patients required debulking procedures during follow-up, whereas none in the ultrathin flap group needed such procedures. There was 1 case of distal marginal necrosis in the conventional group. In the PBD group, 1 flap failed due to thrombotic issues attributed to the short pedicle length of 5 cm. Additional surgical details are provided in Table 2.

Table 2.

Surgical Details

No.	Technique	Flap Length	Flap Width	Pedicle Length	Pedicle	Recipient Artery	Recipient Vein	Complication of Flap	Chief Complaint After Reconstruction	Secondary Procedure	Follow-up
1	Conventional	11	6	8	Desc. LCFA	STA	IJV	—	—	—	6
2	Conventional	12	6	7	Desc. LCFA	STA	IJV	—	—	—	30
3	Conventional	6	9	7	Desc. LCFA	STA	FV	—	Discomfort due to scar band	Debulking	7
4	Conventional	6	9	8	Trans. LCFA	FA	IJV, EJV	—	—	—	11
5	Conventional	10	5	8	Trans. LCFA	STA	FV	—	Discomfort due to flap bulge and redundancy	Debulking	7
6	Conventional	4	8	9	Desc. LCFA	STA	IJV	—	Discomfort due to flap size	—	24
7	Conventional	14	4	8	Trans. LCFA	STA	EJV	—	Discomfort due to scar band	Debulking	10
8	Conventional	25	7	8	Trans. LCFA	FA	FV	Distal necrosis	—	—	8
9	PBD	8.5	4	10	Desc. LCFA	STA	IJV	—	—	—	12
10	PBD	10	6	5	Desc. LCFA	STA	STV	Failed	—	—	18
11	PBD	12.5	5	14	Desc. LCFA	STA	EJV	—	—	—	10
12	PBD	10	5	12	Desc. LCFA	FA	IJV	—	—	—	11
13	PBD	12	5	14	Desc. LCFA	STA	IJV	—	—	—	10
14	PBD	13	6	12	Desc. LCFA	STA	IJV	—	—	—	12
15	PBD	14	6	8	Desc. LCFA	STA	IJV	—	—	—	7
16	PBD	11	5	15	Desc. LCFA	STA	IJV	—	—	—	13

Desc., descending; EJV, external jugular vein; FA, facial artery; FV, facial vein; IJV, internal jugular vein; LCFA, lateral circumflex femoral artery; STA, superior thyroid artery; STV, superior thyroid vein; Trans.: transverse.

For the speech function analysis, 14 patients were evaluated. Overall, articulation was recorded at 84.3%, with 10 patients always understandable, 2 mostly understandable, and 2 usually understandable. Total follow-up duration for speech analysis was 12 (range 6–30) months; the mean follow-up duration was 12.8 (range 6–30) months in the conventional group and 10.8 (range 7–13) months in the PBD group. Two patients in the PBD group did not participate in the speech function analysis. Among the PBD group participants, 6 patients were always understandable in terms of intelligibility, with an articulation score of 89.5% (range 86%–97%). In the conventional elevation group, 1 patient was mostly understandable and 2 were usually understandable, with an articulation score of 80.5% (range 46%–100%) (Fig. 2).

Fig. 2.

Diagram of the outcome of speech analysis comparing the 2 surgical techniques.

DISCUSSION

Reconstruction of the head and neck is complex and includes various options. Depending on the purpose of the reconstruction, different perforator flaps might be selected. However, even when the same donor site is used for harvesting perforator free flaps, the thickness and bulk can vary significantly among patients.¹⁰ Thus, microsurgeons must consider many aspects in each case. Additionally, to reconstruct facial surface defects or intraoral mucosal defects such as the tongue, buccal mucosa, and pharynx, it is necessary to obtain much thinner perforator free flaps compared with other parts of the body.^1,5

Achieving consistent and ideal thin perforator free flaps, regardless of patient conditions, can be challenging. One effective approach is to change the flap elevation planes.⁴ There are 4 main strategies for controlling the thickness and bulk of perforator flaps: (1) selecting the ideal donor site; (2) performing intraoperative defatting procedures; (3) conducting secondary debulking procedures; and (4) altering the flap elevation plane. Thin flaps were first discussed in the 1990s, particularly with abdominal, groin, and ALT flaps.^6–8 Kimura⁹ introduced the microdissection technique around the perforator area under a microscope, which helped extend the pedicle length and create uniformly thin flaps.⁹ The microdissection described in this study involves multiple perforator branch–based elevation for an ultrathin flap.

We previously suggested 4 options for changes in the flap elevation plane: (1) sub–deep facial elevation; (2) supra–deep facial elevation; (3) sub–superficial fascial elevation; and (4) subdermal elevation. Ultrathin subdermal perforator free flaps are defined as those where the perforators are dissected above the deep fascial level up to the subdermal layer. The ultrathin flaps used in this study necessitate microdissection and provide an ideal thickness for tongue reconstruction.

Thin flaps have garnered interest since the 1990s, with a focus on abdominal, groin, and ALT flaps.^5–8 The microdissection concept, introduced in the early 2000s, allows for pedicle elongation and uniform thin flaps.⁹ By anticipating the perforator locations preoperatively, thickness-controlled flap elevation has become more precise and reliable with tools such as computed tomography angiography and high-frequency ultrasound.^4,11 Understanding flap planes is crucial for creating thin flaps, which also helps reduce donor site morbidity.^12–14 Ultrathin ALT flaps with PBD could potentially replace traditional radial forearm free flaps for tongue reconstruction, offering better thickness control.¹⁴ This study demonstrated that despite the thinness of ultrathin flaps, there is no significant difference in functional outcomes related to articulation and intelligibility.

Since the introduction of perforator microdissection in the 1990s, the literature on the effectiveness and safety of this procedure has been limited. Most studies have used microdissected flaps from the ALT, tensor fasciae latae, deep inferior epigastric perforator, and thoracodorsal perforator flaps, primarily for upper and lower limb reconstructions.^6,9,15–17 Few cases have reported the use of microdissected flaps for head and neck reconstructions, mostly in the neck area^9,18 (Table 3). However, this study focused on tongue reconstruction with microdissected ALT flaps, analyzing functional outcomes and flap progress. The ultrathin flaps in this study were a convenient tool for manipulating tongue reconstruction, with the ease of flexibility and reduced chances of secondary procedures. With the use of microdissection, we were able to skeletonize vessels adjacent to the flaps and lengthen the pedicle more than the conventional dissection group (approximately 8–11 cm). This difference in pedicle length in the microdissected group corresponds to a previous study about intra-adiposal vessel anatomy reporting lengths of about 20.3–28.4 mm in the ALT group.¹⁹ However, we had 1 flap failure in the microdissection group due to a short pedicle length, which necessitated using a radial forearm free flap for salvage. This case underscored the importance of harvesting a sufficiently long pedicle for tongue reconstruction. Besides this exception, the flaps progressed well, with no issues affecting speech evaluation due to wound problems.

Table 3.

Comparison of Literature on Microdissected Flap Reconstruction

Author	Year	Case Number	Flap Choice	Area	Average Flap Size, cm2 (Range)
Kimura and Satoh6	1996	5	ALT	Lower extremity 2, upper extremity 1, head neck 1, hand 1	176.6 (126–252)
Kimura9	2002	11	TFL	Lower extremity 3, upper extremity 3, head neck 2, hand 3	68.1 (12–180)
Tas16	2016	2	Prefabricated DIEP	Scrotum 1, head neck 1	98, 450
Liang et al17	2018	5	ALT	Lower extremity 3, upper extremity 1, hand 2 (1 patient)	114.8 (90–150)
Hattori et al15	2020	1	TDAP	Hand 1	54
Current study	2024	8	ALT	Head neck 8	60.4 (50–84)

DIEP, deep inferior epigastic artery perforator flaps; TDAP, thoracodorsal artery perforator flaps.

Although perforator flap techniques have advanced significantly, the routine use of microdissection for head and neck reconstruction is not widespread due to the need to preserve the perforator “hot zone” for flap safety. However, with imaging tools, we successfully elevated ultrathin flaps with microdissection, reducing the need for secondary procedures.

Advantages of ultrathin perforator free flaps include easy stretching, low contracture rates, low donor site morbidity, and indirect linking vessels. Microdissection allows for achieving the thinnest possible flaps safely. However, there is a learning curve to identifying the superficial fascial plane, dissecting and isolating perforators, and managing the risk of short pedicles. Once comfortable with this technique, surgeons can effectively incorporate small vessels branching from the perforator into the flap under magnification. Meticulous hemostasis is essential to prevent venous obstruction due to hematoma or pressure in the microdissected area. With microsurgical experience, flap elevation can be completed in about 30 minutes to 1 hour. Although harvest times were not systematically recorded, our intraoperative experience indicates that, after an initial learning period, the PBD technique can be completed within a similar time frame as conventional ALT flap elevation. Vessel spasm may be problematic, but we have used papaverine irrigation to help prevent such spasm during microdissection.

This study has limitations due to the small patient cohort, but it is the only study focusing on perforator branch–based ultrathin ALT flaps used in tongue reconstruction and their functional outcomes. The review identified 11 microdissection cases performed in 2022 and 2023, with 8 patients reconstructed after hemiglossectomy (Fig. 3). Although statistical power is lacking, the study presented detailed surgical and demographic data for the cohort.

Fig. 3.

Intraoperative photographs of tongue reconstruction with multiple perforator branches based on ultrathin ALT flaps. A, Ultrathin ALT flap. B, Insetting of the flap after tongue resection, showing a thin fat layer and a perforator branch–based dissected pedicle. C, Hemiglossectomy followed by tongue reconstruction with a perforator branch–based ultrathin ALT flap. *Deep fascial perforation site.

The study findings highlight the need for ultrathin ALT flaps, which are easily manipulated for 3D tongue reconstruction and which could replace radial forearm free flaps that leave significant scarring on patients’ forearms. Ultrathin ALT flaps also provided articulation relative to the conventional group and good intelligibility. Further prospective studies are needed to better understand the surgical advantages of ultrathin ALT flaps, including flap elevation time and pedicle length differences.

CONCLUSIONS

PBD for ultrathin ALT flaps performed in hemiglossectomy patients demonstrates functional outcomes comparable to those of the conventional ALT flap. Despite the required learning curve, ultrathin flaps in tongue reconstruction achieve similar success, highlighting their viability as an effective alternative to traditional methods.

DISCLOSURE

The authors have no financial interest to declare in relation to the content of this article.