Licensee OA Publishing London 2013. Creative Commons Attribution License (CC-BY) Bredell M, Grätz K. Sublingual gland flap for reconstruction of anterior and antero-lateral floor of mouth defects. Head Neck Oncol. 2013 Apr 01;5(4):38. Competing interests: none declared. Conflict of interests: none declared. All authors contributed to conception and design, manuscript preparation, read and approved the final manuscript. All authors abide by the Association for Medical Ethics (AME) ethical rules of disclosure.
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Licensee OA Publishing London 2013. Creative Commons Attribution License (CC-BY)
Bredell M, Grätz K. Sublingual gland flap for reconstruction of anterior and antero-lateral floor of mouth defects. Head Neck Oncol. 2013 Apr 01;5(4):38.
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Sublingual gland flap for reconstruction of anterior and antero-lateral floor of mouth defects
M Bredell; K Grätz
Department of Craniomaxillofacial and Oral Surgery, University Hospital of Zürich, Zürich, Switzerland
Manuscript type: Research All authors contributed to conception and design, manuscript preparation, read and approved the final manuscript. All authors abide by the Association for Medical Ethics (AME) ethical rules of disclosure. Competing interests: none declared Conflict of interests: none declared
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Abstract:
Background:
Functional closure of floor of mouth defects remain a challenge. A new method of
reconstruction of the anterior and antero-lateral floor of mouth and mandibular
defects after ablative surgery is described.
Methods:
Six consecutive patients with suitable T1 and T2 floor of mouth and mandibular
alveolar carcinomas were investigated regarding the use of the sublingual gland as a
flap for the coverage of the resection defects.
Results:
In all patients it was possible to mobilize the remaining part of the sublingual gland or
contra lateral sub lingual gland to such an extent that full coverage of the defect was
possible. Vascular perfusion could be maintained in all cases and further healing
was uneventful apart from a mucocele development in one patient.
Conclusions:
The sublingual flap should be considered as a reliable reconstructive option for most
T1 and smaller T2 lesions for the anterior and antero-lateral floor of mouth or
mandible.
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Introduction:
Floor of mouth defects; especially when combined with anterior mandibular defects
may be challenging to reconstruct. Often the defects are closed primarily, left to
granulate or covered by local or regional or even distant flaps.
Most commonly, floor of mouth malignancies such as squamous cell carcinomas lead
to wide resection of the floor of mouth mucosa and submucosal structures (1). Same
can be said for the anterior or antero-lateral mandibular region where the lingual or
buccal mucosa may be involved leading to resection of the mandibular alveolar bone
as well as part of the floor of mouth. For smaller lesions direct closure may be
possible with the aid of local or regional tissue flaps or left to heal by secondary
intention, however larger defects are most commonly covered by split thickness skin
Lesions may be unilateral; however the resultant defects may then extend over the
midline to the contra lateral side. Anatomical structures that may be involved are
multiple and include the mucosa, submandibular and sublingual ducts and orifices(6),
peripheral lingual as well as hypoglossal nerve branches, lingual and deep lingual
arteries, the lingual and sublingual veins, sublingual gland (SLG), genioglossus
muscle as well as the anterior mandibular alveolar bone and mucosa.
Nearly all reconstructive efforts that do not involve the transfer of vascularised tissue
have the potential of scarring with resultant limited mobility of the tongue and
potential speech or chewing impairments. When the labial mucosa is mobilized the
lower lip may be retracted lingually. Ideal reconstructive efforts will utilize local and or
regional tissues with minimal donor site morbidity.
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The purpose of this paper is to describe the use of the sublingual gland, mobilized
sufficiently to be utilized as a vascularised flap with an axial blood supply for
coverage of anterior or antero-lateral floor of mouth and mandibular defects. To the
authors knowledge it is the first description of the use of the sublingual gland flap for
reconstructive purposes.
Anatomical basis:
The sublingual gland is paired and located in the anterior most position of the floor of
mouth. It is wedged between the mandible and genioglossus muscle medially and
lies on the mylohyoid muscle, covered by a thin layer of mobile mucosa. It is
separated from the genioglossus muscle by the lingual nerve as well as the
submandibular duct. Vascular supply comes from the sublingual artery, a branch of
the lingual artery that also supplies the mylohoid muscle and surrounding mucosa
with a midline arterial anastamosis between the left and rights arterial systems.
Venous drainage is through the sublingual and lingual venous system and lymphatic
drainage is to the submental lymph nodes. Parasympathetic innervation exists
through the submandibular ganglion and sympathetic innervations through the
superior cervical ganglion(7). Extension through the mylohyoid muscle may exist with
contact and in some cases apparent fusion with the submandibular gland (SMG) as
the SLG is not bordered by a capsule. Most commonly the sublingual gland is
described to have 8-20 secretory ducts (ducts of Rivinus) while the smaller ducts fuse
into a major duct (Bartholin’s duct). Three variants of ductal anatomy can be
identified with the most common variant where the SLG as well as SMG have major
ducts that merge. Second commonest appears to be multiple small diameter ducts
without a major duct. Least common is where both the SLG and SMG have major
ducts that do not appear to fuse.(6)
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Size of the SLG varies greatly with hypertrophy being described frequently, possibly
more in edentulous patients (8, 9). Age related changes do occur with progressive
increase in ductal structures, acinar atrophy and an increase in adipose tissue that is
often not related to an increase in alcohol intake(10). Herniation of the SLG through
the mylohyoid muscle often occurs and should be considered when performing
mobilization of the SLG (11, 12).
Patients and methods:
Patients with T1 or T2 floor of mouth or anterior alveolar tumors where resection
would lead to a significant defect requiring reconstruction were identified. All patients
routinely received detailed informed consent for tumor resection as well as
reconstruction with either local or regional flaps as well as a possible free flap
reconstruction, mostly a radial forearm free flap if the defect size was greater than
expected. After tumor resection with frozen sections, confirming clear and safe
margins of 5mm or more the defects were accessed for possible reconstructive
options. As the submandibular duct orifices were frequently involved in the resection,
transection of the ducts and more posterior displacement was performed when
indicated. Resections may have involved none or in larger tumors a lesser or larger
component of the component of the SLG.
Careful mobilization of one or both of the whole or remaining part of the SLG from the
overlying mucosa, submandibular duct, the lingual nerve and mylohyoid muscle as
well as from the mandible was then performed, with careful preservation of the
feeding and draining vasculature that can be seen entering the SLG from the side of
the lingual artery. No attempt was made to identify the ducts of the SLG. In most
cases significant mobilization of the SLG could be achieved, even past the anterior
border of the mandible that allowed passive positioning of the SLG flap without
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significant tongue displacement (Fig 2a). Where herniation of the SLG through the
mylohyoid muscle was present the dissection was extended to this level and
separation from the SMG was performed. Fixation was achieved with resorbable
sutures, either to surrounding soft tissues or to the mandibular bone through bur
holes. Surgery was completed by ensuring adequate haemostasis and covering the
defect with a layer of fibrin glue and iodine gauze packing sutured in place and
removed after 7-10 days, further healing took place by secondary intent. Where a
marginal mandibular resection was performed a partial denture was placed as soon
as possible to act as a soft tissue expander. Three patients had concurrent
supraomohyoidal neck dissection and one patient received a sentinel lymph node
biopsy.
Results:
Five patients with defects in the anterior or lateral floor of mouth with concurrent bony
defect and one patient without marginal mandibular resection were treated by this
method. Four patients had T2 and two patients had T1 lesions. In three patients the
resented area was within the canine to canine region and two had more posterior
defects. (Fig 1a) All patients recovered well, one patient presented with a retention
cyst six weeks after surgery that was treated by de-roofing of the retention cyst under
local anesthesia. (Fig 2 b) All patients were partially or fully dentate. Even where an
extensive surface of uncovered bone was involved this could be covered without a
problem.
Table I:
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Where the flap was used to cover a mandibular defect a substantial thickness of
tissue was achieved, but in all cases the placement of a partial denture would be
possible after the removal of the iodine gauze packing. A vestibuloplasty may be
indicated to lower the floor of mouth at time of implant placement or exposure.
Tongue mobility was not inhibited significantly and no secondary revisions were
necessary. No oro-cutaneous fistulas developed and no patients complained of
xerostomia. Slight elevation of the floor of mouth could be observed, but was of little
clinical significance.
Figure 1a
Figure 1b
Figure 2a
Figure 2b
Discussion:
Anterior floor of mouth and anterior mandibular resection defects may pose
significant challenges to the surgeon. Smaller defects can be left to heal by
secondary intention or covered by a split thickness skin graft that fairly consequently
leads to scar contraction. Increasing depth of tumor invasion leads to a deeper
resection and the likelihood of a partial or full resection of the one or both sublingual
glands increases. Microscopic infiltration of the SLG is significantly more common
when the tumor infiltration depth exceeds 5mm (13). Generally reported infiltration
rates of the SLG are as low as 27% (13) or may be as high as high as 48%(1). Intra
operative clinical judgment of the invasion of the SLG may be correct in up to 88% of
cases (13) which can possibly be increased by pre-operative MRI examination. Due
to the various infiltration rates the recommendation to routinely excise the sublingual
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gland as well as the genioglossus muscle (1) cannot be universally accepted. An
individualized approach probably is a wiser way of approaching the different
scenarios regarding infiltration of deeper structures. In most of the smaller tumors
involving the floor of mouth as well as the lingual mucosa of the mandible a
significant portion of the sublingual gland can be preserved. Uncovered mandibular
bone after a marginal resection remains a challenge and has to be covered by local
or regional flaps(14). In smaller defects mobilization of the labial mucosa is an option,
however retraction of the lower lip may be problematic. Regarding regional flaps, the
nasolabial and facial artery musculo-mucosal (FAMM) flaps are the most useful,
however may be problematic in dentate patients. A possible solution to this may be
the island variation of the FAMM flap (3, 4) where the vascular pedicle may be
tunneled through a space of an absent tooth.
Further options are the various tongue flaps (15)or the mere mobilization of the floor
of mouth tissues anteriorly (16). All these options have the risk of impaired tongue
mobility. Another regional flap that allows adequate reconstruction of larger defects of
the floor of mouth is the submental island flap (17) that may be comparative to the
radial forearm free flap. Potential problems with the submental island flap are the
potential excess of adipose tissue and limitations when performing a simultaneous
neck dissection. In our experience the radial forearm free flap stays the flap of
choice for larger defect coverage (18) due to the thin pliable skin that undergoes
minimal scarring and allows for maximal tongue mobility. All of the mentioned
options for defect closure have some component of donor site morbidity or has to be
performed as a two stage procedure.
As the sublingual gland or remnants thereof are freely available and can be utilized
with minimal morbidity, the sublingual salivary gland flap has been demonstrated as
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an option for the closure of defects in the anterior or even the lateral floor of mouth
and anterior or lateral part of the mandible. Significant defects of the mandible as well
as unilateral or contra lateral defects may be covered with adequate mobilization of
this available glandular tissue. Depending on the size of the SLG(8, 9), sizable
defects can be closed in this manner with minimal morbidity and scarring. In this
series no significant complications were noted and the one mucus retention cyst was
treated with minimal effort. As the SLG lends itself to adequate mobilization it has
been demonstrated to be a flap option in the reconstruction after extirpation of T1
and T2 lesions.
In conclusion, many options exist for the reconstruction of anterior and antero-lateral
floor of mouth and mandibular defects and all have their specific advantages and
disadvantages. The sublingual flap should be considered as a reliable reconstructive
option for all T1 and smaller T2 lesions for the anterior and antero-lateral floor of
mouth or mandible.
List of abbreviations:
SLG: Sublingual gland
SMG: Submandibular gland
FAMM: Facial artery musculo-mucosal
Competing interests:
None
Author’s contributions:
Marius Bredell initiated the surgical principle, surgery and drafted the paper
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Astrid Kruse Gujer contributed to the surgery and contributed to the paper
Klaus Grätz contributed to the drafting of the paper
References:
1. Steinhart H, Kleinsasser O. Growth and spread of squamous cell carcinoma of the floor of the mouth. European Archives of Oto-Rhino-Laryngology. [Research Support, Non-U.S. Gov't]. 1993;250(6):358-61. 2. Napolitano M, Mast BA. The nasolabial flap revisited as an adjunct to floor-of-mouth reconstruction. Annals of Plastic Surgery. 2001 Mar;46(3):265-8. 3. Rose EH. One-stage arterialized nasolabial island flap for floor of mouth reconstruction. Annals of Plastic Surgery. [Case Reports]. 1981 Jan;6(1):71-5. 4. Uglesic V, Virag M. Musculomucosal nasolabial island flaps for floor of mouth reconstruction. Br J Plast Surg. 1995 Jan;48(1):8-10. 5. Varghese BT, Sebastian P, Cherian T, Mohan PM, Ahmed I, Koshy CM, et al. Nasolabial flaps in oral reconstruction: an analysis of 224 cases. Br J Plast Surg. 2001 Sep;54(6):499-503. 6. Zhang L, Xu H, Cai Z-g, Mao C, Wang Y, Peng X, et al. Clinical and anatomic study on the ducts of the submandibular and sublingual glands. Journal of Oral & Maxillofacial Surgery. [Research Support, Non-U.S. Gov't]. 2010 Mar;68(3):606-10. 7. S S. Gray's Anatomy. The anatomical basis of clinical practice. 39th ed. London: Elsevier,Ltd.; 2005. 8. Campos LA. Hyperplasia of the sublingual glands in adult patients. Oral Surgery Oral Medicine Oral Pathology Oral Radiology & Endodontics. 1996 May;81(5):584-5. 9. Domaneschi C, Mauricio AR, Modolo F, Migliari DA. Idiopathic hyperplasia of the sublingual glands in totally or partially edentulous individuals. Oral Surgery Oral Medicine Oral Pathology Oral Radiology & Endodontics. 2007 Mar;103(3):374-7. 10. Azevedo LR, Damante JH, Lara VS, Lauris JRP. Age-related changes in human sublingual glands: a post mortem study. Archives of Oral Biology. 2005 Jun;50(6):565-74. 11. Kiesler K, Gugatschka M, Friedrich G. Incidence and clinical relevance of herniation of the mylohyoid muscle with penetration of the sublingual gland. European Archives of Oto-Rhino-Laryngology. 2007 Sep;264(9):1071-4. 12. Nathan H, Luchansky E. Sublingual gland herniation through the mylohyoid muscle. Oral Surgery, Oral Medicine, Oral Pathology. 1985 Jan;59(1):21-3. 13. Clark JR, Franklin JH, Naranjo N, Odell MJ, Gullane PJ. Sublingual gland resection in squamous cell carcinoma of the floor of mouth: is it necessary? Laryngoscope. [Comparative Study]. 2006 Mar;116(3):382-6.
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14. Flynn MB, Moore C. Marginal resection of the mandible in the management of squamous cancer of the floor of the mouth. American Journal of Surgery. 1974 Oct;128(4):490-3. 15. Harris JP, Fabian RL. Central island myomucosal tongue flap. Head & Neck Surgery. [Case Reports Research Support, U.S. Gov't, P.H.S.]. 1983 Jul-Aug;5(6):495-9.
16. Pai PS, Chaturvedi P, D'Cruz AK, Chaukar DA, Pathak KA, Deshpande MS, et al. Reconstruction of early lower gingivo buccal complex lesions using floor of mouth advancement augmented with hyoglossus release. Journal of Surgical Oncology. 2004 Apr 1;86(1):41-3.
17. Paydarfar JA, Patel UA. Submental island pedicled flap vs radial forearm free flap for oral reconstruction: comparison of outcomes. Archives of Otolaryngology -- Head & Neck Surgery. [Comparative Study Multicenter Study
Research Support, Non-U.S. Gov't]. 2011 Jan;137(1):82-7. 18. Matthews RN, Hodge RA, Eyre J, Davies DM, Walsh-Waring GP. Radial forearm flap for floor of mouth reconstruction. British Journal of Surgery. 1985 Jul;72(7):561-4.
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Legends:
Table 1: Overview of patients with floor of moth defects and reconstruction with
sublingual gland flaps
Figures:
Fig 1a: Lateral mandibular and floor of mouth defect with rotation of the SLG to cover
the premolar and molar area
Fig 1b: Healing 10 days after surgery
Fig 2a: Mobilized sublingual flap for coverage of large anterior mandibular defect
Fig 2b: Mucus retention cyst evident 6 weeks after initial surgery (mirror image)
Patient TNM Concurrent
Neckdissection
Depth of
infiltration
Age Area Functional
restriction
Complications
1 T1N0M0 No not reported 54y Mouth floor right No None