Cortical Adaptation following Partial Glossectomy with Primary Closure: Implications for Reconstruction of the Oral Tongue

Adaptive brain activity changes during tongue movement with palatal coverage from fMRI data

Successful adaptation to wearing dentures with palatal coverage may be associated with cortical activity changes related to tongue motor control. The purpose was to investigate the brain activity changes during tongue movement in response to a new oral environment. Twenty-eight fully dentate subjects (mean age: 28.6-years-old) who had no experience with removable dentures wore experimental palatal plates for 7 days. We measured tongue motor dexterity, difficulty with tongue movement, and brain activity using functional magnetic resonance imaging during tongue movement at pre-insertion (Day 0), as well as immediately (Day 1), 3 days (Day 3), and 7 days (Day 7) post-insertion. Difficulty with tongue movement was significantly higher on Day 1 than on Days 0, 3, and 7. In the subtraction analysis of brain activity across each day, activations in the angular gyrus and right precuneus on Day 1 were significantly higher than on Day 7. Tongue motor impairment induced activation of the angular gyrus, which was associated with monitoring of the tongue's spatial information, as well as the activation of the precuneus, which was associated with constructing the tongue motor imagery. As the tongue regained the smoothness in its motor functions, the activation of the angular gyrus and precuneus decreased.

Modification of the anterior-posterior tongue rotation flap for oral tongue reconstruction

The aim of this study is to evaluate the efficacy and long-term outcome of a modification of the anterior-posterior tongue rotation flap used for reconstruction of tongue following cancer ablation. From April 2016 to September 2017, 21 consecutive patients with tumor classification (T2), lymph node classification (N0) tongue cancer on the anterior and middle one-third portion were selected for this study. A modification of the anterior-posterior tongue rotation flap was selected for tongue reconstruction after the cancer resection. Patient's scorings of swallowing, chewing, speech and taste were recorded. Patient after tongue flap reconstruction acquired satisfied tongue movement that allows normal functional outcomes for swallowing, chewing, speech and taste. Local tumor recurrence was not observed during the follow-up examination (range, 12-24 months). The modification of the anterior-posterior tongue rotation flap was a safe and reliable treatment for medium-size tongue cancer (T2N0), especially suitable to patients who cannot endure prolonged surgery.

Patient-Reported Quality of Life After Resection With Primary Closure for Oral Tongue Carcinoma

OBJECTIVES/HYPOTHESIS

For early-stage oral tongue carcinoma and carcinoma in situ (ESOTCCIS), we evaluated patient-reported quality-of-life (QOL) outcomes following resection with primary closure (R-PC).

STUDY DESIGN

Retrospective review at an academic cancer center.

METHODS

Thirty-nine ESOTCCIS patients (Tis, T1, T2) who underwent R-PC without radiation completed the University of Washington Quality of Life Questionnaire Version 4 (UW-QOL) at least 6 months since R-PC (mean = 2.39 years; range = 0.5-6.7 years). We compared UW-QOL scores for pain, swallowing, chewing, speech, and taste to established normative population scores. Multivariable regression analysis evaluated factors associated with QOL impairment.

RESULTS

ESOTCCIS patients who underwent R-PC in comparison to the normative population reported significantly worse mean speech (87.7 vs. 98, P < .001) and taste (85.6 vs. 95, P = .002) scores and no significant differences in mean pain (91.7 vs. 86, P = .96), swallowing (100 vs. 98, P = .98), chewing (97.4 vs. 94, P = .98) scores. For speech and taste, 59% (23/39) reported no postoperative change from baseline, whereas 41% (16/39) and 35.9% (14/39) reported mild impairment, respectively. Overall, postoperative QOL was reported as good, very good, or outstanding by 87.2% (34/39). Higher American Society of Anesthesiologists class, cT1 compared to CIS, and ventral tongue involvement were independently associated with worse speech. Age < 60 years was independently associated with worse taste.

CONCLUSIONS

ESOTCCIS patients who undergo R-PC without radiation can expect long-term swallowing, chewing, and pain to be in the normative range. Although a majority of patients can expect to achieve normative speech and taste outcomes, R-PC carries the risks of mild speech and/or taste impairments.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:312-318, 2021.

An interactive surgical simulation tool to assess the consequences of a partial glossectomy on a biomechanical model of the tongue

Oral cancer surgery has a negative influence on the quality of life (QOL). As a result of the complex physiology involved in oral functions, estimation of surgical effects on functionality remains difficult. We present a user-friendly biomechanical simulation of tongue surgery, including closure with suturing and scar formation, followed by an automated adaptation of a finite element (FE) model to the shape of the tongue. Different configurations of our FE model were evaluated and compared to a well-established FE model. We showed that the post-operative impairment as predicted by our model was qualitatively comparable to a patient case for five different tongue maneuvers.

Functional magnetic resonance and swallowing: critical literature review

Introduction

Aspects of the neuroanatomical representation of swallowing have been investigated in humans through brain mapping techniques, such as functional magnetic resonance imaging (fMRI).

Objective

This critical qualitative review of the literature analyzed international scientific publications in the PubMed database that investigated the activation of the central nervous system in humans during the act of swallowing.

Methods

This investigation was limited to articles that investigated adults older than 18 years, published in English or Portuguese, between January 2002 and December 2013. Publications that did not have access to the full text, that were repeated by overlapping keywords, case studies, literature reviews, letters to the editor, and those not directly related to the topic of the investigation were excluded.

Results

A total of 649 articles were identified, of which 21 matched the inclusion criteria.

Conclusion

The main purpose of the manuscripts that investigate the swallowing process through fMRI were: to characterize swallowing in different pathologies; to compare swallowing in different age groups; to describe brain activation in different stimulation conditions. These studies indicate multiple cortical regions involved in swallowing control. Overall, the studies indicate that fMRI is a non-invasive and quantitative method that allows the investigation of characteristics that are quite often not clinically visible.

Effect of articulatory rehabilitation after oral cancer surgery on higher brain activation

The present study aimed to verify the importance of postoperative articulatory rehabilitation in patients with oral cancer and to clarify the neurological changes underlying articulatory functional recovery. A longitudinal assessment of oral function and accompanying brain activity was performed using non-invasive functional magnetic resonance imaging (fMRI). We assessed 13 patients with cancers of the tongue and oral floor before and after ablative surgery. Articulatory function was assessed preoperatively and postoperatively using a conversation intelligibility test and the Assessment of Motor Speech for Dysarthria test. Patients also performed a verbal task during fMRI scans. The assessments were then repeated after the patients had undergone 4-6 months of articulatory rehabilitation therapy. Compared to pretreatment levels, articulatory rehabilitation resulted in a significant increase in activation in the supplementary motor cortex, thalamus, and cingulate cortex. The present study offers a quantitative assessment of the effects of speech rehabilitation by investigating changes in brain activation sites.

Quality of life outcome measures using UW-QOL questionnaire v4 in early oral cancer/squamous cell cancer resections of the tongue and floor of mouth with reconstruction solely using local methods

Cancer treatment either by surgery alone or in a combination of surgery, radiotherapy±chemotherapy has significant consequences on the physical, mental, emotional and psychosocial wellbeing of the patient. Measurement of quality of life (QOL) is necessary to understand the patient's perception of their own treatment, as clinicians' views can be biased. Reconstruction of a cancerous defect with a free vascular flap is ideal in large, often composite defects, provided it is appropriate to the advanced stage and prognosis of the disease, medical condition of the patient, availability of surgical and financial resources and allows the prosthetic rehabilitation of the anatomic area. Using University of Washington Quality of life 4 questionnaire (UW-QOL4), we assessed the QOL of 38 patients, who underwent local surgical reconstructions after resection of T1/T2 tongue/floor of mouth squamous cell carcinoma defects. Objective assessment of speech and swallow function was also carried out using therapy outcome measure (TOM) scores by the speech and language therapy team (SALT) aiming to see the differences in the scores obtained in patients who underwent post-operative radiotherapy. Our study, conducted 6months after completion of all oncologic treatment for the primary disease, showed satisfactory levels of quality of life parameters with good function showing that local reconstructive methods are successful and may have benefits in the management of early oral cancers involving the tongue and floor of mouth. They are beneficial by providing a good quality in terms of function, by reducing the operating time, the surgical morbidity, simplifying post-operative care and thereby becoming an efficient, effective and a cost effective method.

Cortical activation during swallowing rehabilitation maneuvers: a functional MRI study of healthy controls

OBJECTIVE/HYPOTHESIS

We hypothesize that the central response during swallowing rehabilitation is critical and may be exploited to maximize the therapeutic benefit. We seek to provide preliminary data regarding the neural networks associated with commonly employed rehabilitation strategies to increase our understanding of the neural bases underlying these maneuvers.

STUDY DESIGN

Case series.

METHODS

Ten healthy adults (five males, five females), ranging in age from 20 to 30 years (mean age = 25 years, SD = 2.5 years) with no previous history of neurologic illness or swallowing complaint were subjected to a single-trial functional magnetic resonance imaging (fMRI) paradigm. The experimental tasks consisted of three swallow maneuvers, dry swallow, Effortful swallow, and the Mendelsohn maneuver.

RESULTS

Multiple regions including the cingulate gyrus, inferior frontal gyrus, insula, pre- and postcentral gyrus, inferior parietal lobe, superior frontal gyrus, supramarginal gyrus thalamus, were detected. The Effortful swallow, when compared to the dry swallow, elicited significant differential activation in the left superior temporal gyrus, left insula, left inferior parietal lobe, bilateral medial frontal gyrus, and right anterior cingulate. The Mendelsohn maneuver, when compared to the dry swallow, elicited significant activation in the bilateral postcentral gyrus, bilateral precentral gyrus, bilateral cingulate gyrus, bilateral medial frontal gyrus, left inferior parietal lobe, left supramarginal gyrus, and right insula.

CONCLUSIONS

Our findings suggest that a single-trial design is sensitive to delineate a widespread neural network of activation in both hemispheres associated with rehabilitation tasks. Both the Effortful swallow and Mendelsohn maneuvers elicited significantly higher responses in regions related to swallowing, suggestive of enhanced cortical activation during these tasks.

Functional MRI of tongue motor tasks in patients with tongue cancer: observations before and after partial glossectomy

INTRODUCTION

The current study seeks to provide preliminary data regarding this central, adaptive response during tongue motor tasks utilizing functional magnetic resonance imaging (fMRI) before and after glossectomy.

METHODS

Six patients, with confirmed histological diagnoses of oral tongue cancer, underwent fMRI before and 6 months after partial glossectomy. These data were compared to nine healthy controls. All subjects performed three tongue motor tasks during fMRI: tongue tapping (TT), dry swallow (Dry), and wet swallow (Wet).

RESULTS

Following surgery, increased activation was subjectively observed in the superior parietal lobule, supplementary motor area, and anterior cingulate. Region of interest (ROI) analysis of the precentral gyrus confirmed increased cortical activity following surgery. In addition, comparisons between pre-surgical scans and controls suggested the dry swallow task was sensitive to elicit tongue-related activation in the precentral gyrus (p ≤ 0.05).

CONCLUSIONS

The adaptive changes in the cortex following partial glossectomy reflect recruitment of the parietal, frontal, and cingulate cortex during tongue motor tasks. In addition, post-operative activation patterns more closely approximated control levels than the pre-operative scans. Furthermore, the dry swallow task appears most specific to elicit tongue-related cortical activity.

Cortical compensation associated with dysphagia caused by selective degeneration of bulbar motor neurons

According to recent neuroimaging studies, swallowing is processed within multiple regions of the human brain. In contrast to this, little is known about the cortical contribution and compensatory mechanisms produced by impaired swallowing. In the present study, we therefore investigated the cortical topography of volitional swallowing in patients with X-linked bulbospinal neuronopathy (Kennedy disease, KD). Eight dysphagic patients with genetically proven KD and an age-matched healthy control group were studied by means of whole-head magnetoencephalography using a previously established swallowing paradigm. Analysis of data was carried out with synthetic aperture magnetometry (SAM). The group analysis of individual SAM results was performed using a permutation test. KD patients showed significantly larger swallow-related activation of the bilateral primary sensorimotor cortex than healthy controls. In contrast to the control group, in KD patients the maximum activity was located in the right sensorimotor cortex. Furthermore, while in nondysphagic subjects a previously described time-dependent shift from the left to the right hemisphere was found during the one second of most pronounced swallow-related muscle activity, KD patients showed a strong right hemispheric activation in each time segment analyzed. Since the right hemisphere has an established role in the coordination of the pharyngeal phase of swallowing, the stronger right hemispheric activation observed in KD patients indicates cortical compensation of pharyngeal phase dysphagia.

The importance of preoperative swallowing therapy in subtotal laryngectomies

Objective: To examine the utility of swallowing therapy (ST) before and after surgery in patients undergoing subtotal laryngectomy.

Study Design and Setting: From 1990 to 2000, 43 patients underwent subtotal laryngectomy. Prior to 1997 patients received ST only after surgery, while from 1997 on, patients scheduled for subtotal laryngectomy also received some sessions of ST before surgery.

Results: The average time to swallowing resumption was 27.76 ± 5.206 days for the 25 patients who received ST only after surgery, and 16.38 ± 2.953 for those who underwent ST both before and after surgery.

Conclusion: The difference between the two groups was significant on Student's t test ( P < 0.001) and shows that preoperative rehabilitation is of significant help in the early resumption of normal deglutition.

Significance: The authors find that the duration of nasogastric tube feeding is reduced in subjects who underwent ST.

Increased midsagittal tongue velocity as indication of articulatory compensation in patients with lateral partial glossectomies

BACKGROUND

The purpose of this study was to describe the impact of partial lateral glossectomy on midsagittal tongue movement during speech.

METHODS

Using B-mode ultrasound, the midsagittal tongue movement of 10 patients with lateral partial glossectomy during a standardized reading passage was analyzed before and after surgery. Six normal adults served as control speakers. The main outcome measure was the tongue velocity during speech. The technique of defect reconstruction (local vs flap) was included as a covariate in the analysis.

RESULTS

Following the surgery, all patients significantly increased the velocity of the midsagittal tongue movements during the reading passage.

CONCLUSION

The results demonstrated that the patients with partial glossectomy compensated for the lateral tongue resections by increasing the velocity of the residual tongue during speech. The study provides first insights into the biomechanical aspects of spontaneous articulatory compensation following lateral tongue resections.

Tongue reconstruction: recent advances

PURPOSE OF REVIEW

To examine the recent literature concerning advances in tongue reconstruction after tumor resection.

RECENT FINDINGS

Reconstruction following resection of malignant tongue tumors remains one of the most difficult problems in head and neck oncology. Recent trends in tongue reconstruction have focused on optimizing speech and swallowing function and maximizing quality of life. In the recent literature, several new reconstructive strategies including omohyoid musculocutaneous and myofascial flaps overlayed with radial forearm free flaps have been described. In addition, several older reconstructive options, such as trapezius and pectoralis rotational flaps, have been revisited. There has also been a trend toward restoring innervation to these flaps rather than leaving them insensate.

SUMMARY

Tongue cancer resection and subsequent reconstruction pose interesting challenges to the surgeon to maximize postoperative function and quality of life. Attention to the principles of tongue reconstruction and knowledge of the range of available reconstructive options can result in more favorable functional outcomes.

Normal swallowing and functional magnetic resonance imaging: a systematic review

Unknowns about the neurophysiology of normal and disordered swallowing have stimulated exciting and important research questions. Previously, these questions were answered using clinical and animal studies. However, recent technologic advances have moved brain-imaging techniques such as functional magnetic resonance imaging (fMRI) to the forefront of swallowing neurophysiology research. This systematic review has summarized the methods and results of studies of swallowing neurophysiology of healthy adults using fMRI. A comprehensive electronic and hand search for original research was conducted, including few search limitations to yield the maximum possible number of relevant studies. The participants, study design, tasks, and brain image acquisition were reviewed and the results indicate that the primary motor and sensory areas were most consistently active in the healthy adult participants across the relevant studies. Other prevalent areas of activation included the anterior cingulate cortex and insular cortex. Review limitations and suggested future directions are also discussed.