Article Figures & Data
Figures
- Fig 1.
Illustrative schematic demonstrating the key steps in the SMG transfer operation, including mobilization or ligation of the facial artery and vein proximal to the SMG, anterior and inferior translation of the gland into the submental space, and bisection of the mylohyoid muscle to allow repositioning of the submandibular duct and ganglion.3,7
- Fig 2.
Contrast-enhanced CT images demonstrating the typical asymmetric appearance of the submental and submandibular spaces after SMG transfer. The left transferred SMG (arrows) is elongated and displaced inferiorly and anteriorly into the submental space superficial to the anterior belly of the digastric muscle (arrowheads), resulting in an asymmetric soft-tissue density in the submental space and diminished soft-tissue volume in the submandibular space relative to the contralateral gland (asterisks). Note also edema of surrounding tissues in this patient who was 3 months postchemoradiation with cisplatin and NRG-HN002 (NCT02254278; ClinicalTrials.gov) de-escalation protocol at time of imaging.
- Fig 3.
Appearance of SMG (arrows) transferred deep to the anterior belly of the digastric muscle (arrowheads) on axial T2-weighted, fat-suppressed imaging and coronal T1-weighted imaging. The patient was 2 months postchemoradiation with cisplatin and intensity-modulated radiation therapy at imaging.
- Fig 4.
Axial and coronal fat-suppressed postcontrast T1-weighted imaging performed 28 days postoperatively for staging purposes demonstrated platysma enhancement (arrows) adjacent to the transferred SMG. The patient had not yet undergone chemoradiation at imaging.
- Fig 5.
Postoperative asymmetry within the submandibular space results in misinterpretation of the superior aspect of the normal contralateral SMG (arrows) as a parapharyngeal mass (axial T2 fat-suppressed and postcontrast imaging). The patient was 2 months postchemoradiation with cisplatin and intensity-modulated radiation therapy at imaging.
- Fig 6.
PET/CT images demonstrating mildly increased FDG uptake in the left transferred SMG (arrows) compared with the contralateral gland (asterisk) 5 months after SMG transfer surgery and 3 months following conclusion of chemoradiation. These findings are congruent with previously published PET findings in a SMG transfer operation and may reflect relatively preserved function in the transferred gland.8
Tables
Morphologic Measurement Definition Direction of Measurement AP length As measured between anteriormost border of gland and posteriormost border of SMG On axial images, perpendicular to axis connecting the mandibular condyles AP length difference Difference between the AP lengths of the SMGs by subtraction of the AP length of the contralateral gland from the transferred gland On axial images, perpendicular to axis connecting the mandibular condyles Posterior margin difference Distance between the posteriormost border of the gland and that of the contralateral gland On axial images, perpendicular to axis formed by connecting the mandibular condyles Superior margin difference Distance between the superiormost border of the gland and that of the contralateral gland On coronal images, perpendicular to axis formed by connecting the mandibular condyles Anteroinferior margin difference Distance between the anteroinferior-most border of the gland and that of the contralateral gland On axial images, perpendicular to axis formed by connecting the mandibular condyles Note:—AP indicates anteroposterior.
Patient No. Primary Tumor Site Prescribed Dose to Primary Tumor (Gy) Prescribed Dose to Involved Neck (Gy) Mean Dose to SMG on Involved Side (Gy) Prescribed Dose to Uninvolved Neck (Gy) Mean Dose to Transferred SMG (Gy) 1 R BOT 60 54 58.64 48 20.45 2 R tonsil 69.96 59.4 61.33 54.12 28.99 3 R tonsil 69.96 59.4 68.8 54.12 43.97 4 R BOT 69.96 59.4 66.01 59.4 41.44 5 R BOT 60 54 60.01 48 44.95 6 L tonsil 66 59.4 66.7 54.12 16.59 7 R tonsil 66 59.4 59.4 54.12 38.8 8 R tonsil 69.96 59.4 72.7 54.12 27.17 9 Nasopharynx 69.96 59.4 61.02 59.4 60.77 Average dose (Gy) 66.87 58.20 63.85 53.93 35.90 SD 4.24 2.38 4.89 4.04 13.88 Note:—R indicates right; BOT, base of tongue; L, left.
↵a Postsurgical radiation dosages for the 9 out of 11 patients who received radiation therapy at our institution following the SMG transfer procedure. Per the Student t test, the transferred SMG received a significantly lower radiation dose than the contralateral SMG (P < .001).
Preoperative (mm) P Value Postoperative (mm) P Value Anteroposterior length difference 2.5 (−4–5) .28 10.5 (−1–17) <.001 Anteroinferior margin difference 0 (0–0) 13.5 (10–16) <.001 Posterior margin difference −1.8 (−9–3) .10 7.2 (0–16) <.001 Superior margin difference 0.2 (−3–6) .79 −7.5 (−15–0) <.001 ↵a Preoperative and postoperative morphologic features of the transferred SMGs, presented as averaged length and location differences between the SMGs in each patient (transferred gland–contralateral gland) followed by ranges of the differences. Positive values indicate anterior and superior directions, respectively. P values for significance of length differences are derived from paired pre- and post-t tests with a reference value of 0 mm (no difference).
