Feasibility of Endoscopic Sentinel Node Biopsy in the Porcine Neck

Ultrasound-guided contrast-enhanced sentinel node biopsy of the head and neck in a porcine model

Objective

To test the feasibility of contrast-enhanced ultrasound (CEUS)–guided sentinel lymph node biopsy (SNB) of the head and neck in a porcine model.

Study Design and Setting

In this prospective, non-randomized study, methylene blue and Sonazoid were injected into the lateral tongue or floor of mouth (FOM) of four swine. Real-time CEUS was used to identify contrast in the lymphatic channels flowing to the sentinel lymph node (SLN). Endoscopic or open SNB was performed. Neck dissection was then performed, and the residual nodal packet was examined for remaining contrast-enhancing or blue dye–stained nodes.

Results

In all eight procedures, the SLN was visualized with ultrasound and blue dye. Seven procedures identified a single SLN, and one identified two SLNs. Subsequent neck dissections revealed no other nodes containing methylene blue or contrast in the nodal specimen or operative bed.

Conclusion/Significance

CEUS-guided SNB of the head and neck in swine is feasible, with success comparable to blue dye–guided SNB. This technique may offer several advantages over traditional techniques, and warrants further study.

Feasibility of ICG fluorescence-guided sentinel node biopsy in animal models using the HyperEye Medical System

BACKGROUND

The sentinel lymph node (SLN) concept is accepted for several types of cancers. Current methods for sentinel node detection involve radioisotopes and blue dye. They have shown good results, but some drawbacks remain. Indocyanine green (ICG) fluorescence using the HyperEye Medical System (HEMS) was evaluated as a new method.

METHODS

This was a prospective, nonrandomized, experimental study in four Japanese white rabbits and six Yorkshire pigs. ICG and indigo carmine were injected into the tongue, larynx, or hypopharynx, and ICG fluorescence detection was evaluated using both transcutaneous visualization of lymphatic vessels and intraoperative identification of SLNs.

RESULTS

The SLNs appeared as shining fluorescent spots with HEMS transcutaneously in rabbits, but no SLNs were detected transcutaneously in pigs. Eleven procedures identified SLNs, but one did not due to a technical problem.

CONCLUSIONS

HEMS could become useful for predicting lymph node metastasis during surgery for head and neck cancer.

Extracervical approaches to endoscopic thyroid surgery

There is increasing demand for surgical procedures which avoid visible scars while maintaining optimal functional and ideal cosmetic results, without compromising the safety or effectiveness of the procedure. Endoscopic techniques have been adapted to abdominal and pelvic surgery and increasingly employed over the past three decades. Although hampered by the absence of a natural cavity, endoscopic techniques have been adapted to surgery in the neck for the past 15 years, particularly for the thyroid gland. While earlier attempts at endoscopic thyroid surgery were performed through incisions in or near the midline of the neck, recent techniques have been developed to place the incisions and endoscopic ports extracervically, or at least away from the midline region of the neck, rendering the cosmetic result more acceptable. Most of these approaches are through the axilla, breast, chest wall or a combination of approaches. Visualization of the thyroid and rate of complications with these approaches are equal to those attained with older endoscopic approaches. Careful patient selection is important for endoscopic surgery. Complications unique to the endoscopic approach are mostly related to insufflation of cervical tissues with pressurized CO(2).

Thyroid lymphosonography: a novel method for evaluating lymphatic drainage

OBJECTIVES

We evaluated lymphosonography, or contrast-enhanced, ultrasonography (US)-guided sentinel lymph node (SLN) detection, as a technique for demonstrating the lymphatic drainage of the thyroid gland.

METHODS

In this prospective animal study, four 50-kg Yorkshire swine underwent transcutaneous injection of a US contrast agent and methylene blue dye into the thyroid gland. Contrast-enhanced US was used to identify draining lymphatic channels and SLNs. Sentinel node biopsy was conducted. Subsequently, bilateral neck and upper mediastinal dissection was carried out.

RESULTS

In 3 of 4 cases, a blue dye-positive and US contrast-positive SLN was identified. We identified SLNs in level IV in 2 cases. One case revealed 2 adjacent nodes in the superior mediastinum. In 1 case, a lymphatic channel was identified traveling into the mediastinum, but exposure of the SLN could not be obtained. No residual blue dye-positive or US contrast-positive nodes were identified on subsequent dissection.

CONCLUSIONS

Lymphosonography of the thyroid gland in a porcine model correlates well with blue dye-guided sentinel node biopsy and is technically feasible, although in some cases access to the SLN may be difficult. This technique could potentially enable a detailed analysis of thyroidal lymphatic drainage if applied to humans.

Minimally invasive neck surgery. Surgical feasibility and physiological effects of carbon dioxide insufflation in a unilateral subplatysmal approach

Endoscopically assisted, minimally invasive techniques to regions without a natural cavity require insufflation with carbon dioxide (CO2). In the neck region this may impair hemodynamics, blood gas homoeostasis, cerebral blood circulation and increase the intracranial pressure. An exclusively endoscopic unilateral subplatysmal approach to the submandibular region was investigated in nine mini-pigs randomized to three groups. On both neck sides, within a 14 day interval, the subplatysmal space was inflated with CO2 at 10 mmHg, 20 mmHg (1.33/2.66 x 10 (3)Pa) or 20 mmHg (2.66 x 10 (3)Pa) combined with mechanical suspension. Data for hemodynamic and blood gas parameters, gas volumes, and intracranial pressure were obtained preoperatively, 30 min after onset and 10 min postopeatively. In a pocket created by insufflation of 20 mmHg (2.66 x 10 (3)Pa), exposition and resection of the submandibular gland were accomplished easily. The elevation procedure had technical disadvantages. The mean operation time was 48.9 min. Unilateral subplatysmal carbon dioxide insufflation of the submandibular neck region up to 20 mmHg (2.66 x 10 (3)Pa) did not affect physiological parameters. As an exclusive endoscopical approach for unilateral surgery of the submandibular region, the use of inflation pressures of up to 20 mmHg (2.66 x 10 (3)Pa) might be considered.

Lymphosonographic sentinel node biopsy of the supraglottis in a swine model

OBJECTIVE

To test the feasibility of a novel contrast-enhanced ultrasound (CEUS) technique, or lymphosonography, for sentinel node biopsy (SNB) of the supraglottis in a porcine model.

STUDY DESIGN AND SETTING

In this prospective, nonrandomized animal study, blue dye and ultrasound contrast agent were injected into the supraglottis in seven 50-kg Yorkshire swine. Transcutaneous CEUS was used to identify real-time lymphatic flow of contrast through lymph channels (LC) to the sentinel lymph node (SLN). SNB was carried out, visually identifying a blue node, with the assistance of intraoperative CEUS. Bilateral modified radical neck dissections were performed to search for any residual contrast-positive or blue SLNs.

RESULTS

In each case, at least one SLN was identified by preoperative CEUS. A total of 12 nodes were identified on preoperative CEUS, and 11 of 12 nodes were stained with blue dye (91.7%). No residual blue or contrast-positive nodes were identified on neck dissection.

CONCLUSIONS

Lymphosonographic SNB of the supraglottis in a porcine model is technically feasible, and yields results comparable to traditional blue dye-guided techniques. No "shine-through" effect or nonsequential nodal enhancement occurred. This technique holds promise for sentinel node biopsy and allows a novel method for in vivo investigation of the lymphatic system.

Head and neck cancer: an evolving treatment paradigm

Since the inception of this journal in 1948, the understanding of etiologic factors that contribute to and the treatment of head and neck cancer has evolved dramatically. Advances in surgery, radiation therapy, and chemotherapy have improved locoregional control, survival, and quality of life. The outcomes of these treatment modalities have shifted the focus of curative efforts from radical ablation to preservation and restoration of function. This evolution has been documented in the pages of Cancer for the past 6 decades. This review focuses on the evolution of treatment approaches for head and neck cancer and future directions while recognizing the historic contributions recorded within this journal.