Introduction

In the era of organ preservation surgery, transoral robotic surgery (TORS) is used by an increasing number of head and neck surgeons for the treatment of pharyngo-laryngeal tumors [1–4]. The Da Vinci surgical system (Intuitive Surgical Inc, Sunnyvale, CA, USA) is mostly used in the oropharynx, supraglottis and piriform sinus for the treatment of malignant and sometimes benign tumors [5–9].

Classically, the Da Vinci system uses an electrocautery monopolar or bipolar that is manipulated by one of the robotic arms.

One drawback of the TORS is the high thermal effect of the electrocautery inducing edema and crusting. We proposed to use the new CO2 laser wave guide (CO2 LWG) (Lumenis, Santa Clara, CA, USA) in TORS to minimize this thermal effect.

In this prospective study, we present our early experience with the use of the CO2 LWG associated to the Da Vinci surgical system for the treatment of malignant tumors of the pharynx and supraglottis.

Methods

From August 2010 to September 2010, four patients were enrolled in this prospective trial on TORS using the Da Vinci surgical robot with the CO2 LWG, in our University Hospital.

Inclusion criteria were: patients older than 18 years with early stage tumors (T1, T2) involving the oral cavity, base of tongue, pharynx, or supraglottic larynx, who signed an informed consent. Exclusion criteria were: medical conditions contraindicating general anaesthesia; patients with tumors not accessible to TORS after prior evaluation under general anaesthesia and attempts to place various available retractors.

The approval of the ethical committee of the Louvain University Hospital at Mont-Godinne was obtained to perform this study. Procedures were documented with still and video photography.

Patients assessment

The preoperative work-up of patients included clinical examination, PET/CT, or CT with contrast of the neck, chest X-ray, liver function tests, direct laryngoscopy and biopsy. During the general anaesthesia for direct laryngoscopy, we tried to position the appropriate retractor to verify if the patient is eligible for TORS.

Anaesthesia technique

Ventilation was performed through the smallest laser-safe endotracheal tube possible (inner diameter: 6 mm; Hi/Lo, Mallinckrodt Medical, Athlone, Ireland). To allow appropriate positioning of the mouth gag and cheek retractor, the tube was not fixed with adhesives but carefully handled by the surgeon.

Surgical setting

All the procedures were performed in the same operating room by the same surgical and nursing team. The surgical setting was described in more details in a previous article [10].

The surgical robotic cart was positioned 30° from the surgical bed on the left side of the patient. It is equipped with a robotic manipulator and four mounted arms. However, we only used three of the robotic arms: one arm held a 0° endoscope, one arm held a 5-mm EndoWrist® (Intuitive Surgical Inc.) Maryland atraumatic forceps and one arm held the CO2 LWG introduced via the robotic arm introducer. The wave guide (WG) is a hollow glass waveguide with an internal core of 500 μM and outer diameter of 1,040 μM. The inner surface is coated with a metallic silver layer and an innermost silver iodide layer acting as a reflective mirror. The glass tube has an external biocompatible coating. The WG has a length of 2 m providing easy adaptation to TORS.

The effective spot size at the tip of the WG is 320 μM and the WG is characterized by minimal beam divergence allowing working in non-contact mode at a distance of up to 15 mm.

The instruments were introduced 30° laterally from the arm supporting the 0° endoscope and were placed in the right or left arm of the robot, respectively, depending on tumor localization and/or surgeon decision (Fig. 1). Places could be switched intraoperatively depending on the surgeons’ preference. The laser unit was placed at the right side of the patient. The laser parameters were: superpulse or continuous mode, 7–15 W, continuous delivery.

Fig. 1
figure 1

Introperative transoral view showing the CO2 LWG handled by the robotic arm

Full size image

The surgeon’s console was positioned away from the patient, on his left side. At the console, the surgeon controls the instrument arms and camera by maneuvering the master robotic manipulators. A second surgeon was seated at the head of the patient. The video tower was on the right side of the patient. One cautery unit was used, and it was connected to a coagulating suction tube handled by the second surgeon at the head of the patient.

A double cheek retractor (Hager and Werken, Duisburg, Germany) was used to protect the patient’s lips. Eye shields were also used (EMS Medical Ltd, Gloucester, UK). The patient’s face was covered with moist gauzes. The LARS retractor (Fentex, Tuttlingen, Germany) was used in all the surgeries. It was suspended anteriorly with a Fentex laryngoscope holder (Fentex, Tuttlingen, Germany).

For smoke aspiration, a flexible aspiration tube, with continuous aspiration, was introduced into the nasopharynx through the right or left nostril and held in place with an adhesive tape.

Tumor resection followed the principles of the European Laryngological society for supraglottic tumors [11]. For tonsil tumors the technique used was similar to that described by Weinstein et al. [8], for base of tongue tumors the technique was similar to that described by Moore et al. [9]. Hemostasis was achieved using the CO2 LWG and the suction–coagulation when necessary.

The surgical specimen was oriented on a cork plate for histological examination after formalin fixation. Additional margins from the surgical bed were taken in regions close to the tumor to investigate the adequacy of tumor removal and sent for frozen section analysis. After tumor resection, the surgical field was covered with a thin film of fibrin glue (Tissucol® Baxter, Vienna, Austria). Hematoxylin and eosin (H&E)-stained representative tissue sections were examined for histopathological analysis, in measuring the extent of coagulation depth.

Management of the neck

Patients with negative necks on clinical and radiological examination were enrolled in the sentinel node study ongoing in our institution [12]. If the sentinel node was positive for tumor invasion, neck dissection was performed in the next 3 weeks. For patients with positive clinical and/or radiological necks, unilateral/bilateral modified radical neck dissection was performed in the same surgical time.

Postoperative care

No tracheostomy was performed, but all patients were monitored for 24 h in the intensive care unit. All patients had systematic steroids for 72 h and inhaled steroids for 1 week. All patients had antibiotics for 1 week. Patients had a small nasogastric feeding tube inserted during the surgery and had intensive swallowing therapy starting on the following day of the surgery.

Results

Four patients (three men and one woman) were included in this study. The mean age was 56 years (range 53–62 years). Two patients had supraglottic tumors (one epiglottic tumor, one aryepiglottic fold tumors), two had pharyngeal tumors (one tonsil tumor, one tongue base tumor). Three patients had T1 tumors and one had a T2 tumor. The types or surgeries performed are: two transoral robotic supraglottic laryngectomies, one transoral robotic tonsillectomy, one transoral robotic partial pharyngectomy. In all cases, negative resection margins were achieved on frozen section analysis, and confirmed with routine histological examination. None of them received intraoperative reconstruction. Two patients had N0 clinical and radiological necks, one was staged N1 and one was staged N2b. Neck exploration with the sentinel node technique was performed in patients with N0 necks, unilateral functional neck dissection was performed in the patient with T1N1 of the tonsil and bilateral functional neck dissection was performed in the patient with T2N2b of the epiglottis. The pathological staging was concordant with the clinical staging.

None of the patients required tracheotomy and there were no intraoperative complications related to the use of the robot or the CO2 LWG. Only one laser fiber was used for each of the surgeries, there was no need to replace a fiber because it was defective or broken. The mean coagulation depth was 200 μm (range 100–300).

There were no postoperative complications (airway obstruction, bleeding…). The mean follow-up time is 9 months. This period is insufficient for adequate oncologic control data for comparison with other treatments. However, no recurrences were noted until the writing of the article.

Time-parameters assessed

The time required to complete two stages of the operation was carefully documented. These stages are: the installation of the mouth retractor to achieve adequate exposure and the operative procedure.

Exposure of the surgical field

The mean time required for installation of the mouth retractor to achieve adequate exposure of the surgical field was 30 min, with a range of 10–60 min.

Duration of the operative segment

The mean overall surgical time was 94 min with a range of 60–125 min.

The mean hospital stay was 6 days (4–9 days). Oral feeding was resumed at 3 days (1–5 days) under speech therapy control. The patients left the hospital with complete oral feeding.

Healing seemed faster than what was observed with the use of electrocautery.

Discussion

The role of TORS is increasing in the treatment of tumors of the larynx and pharynx. Its advantages are numerous, compared to traditional endoscopic surgery. Natural hand tremor is filtered out, large hand movements of the operator are adjusted to small movements of instruments in the airway enhancing dexterity and finally the surgeon is given a true depth perception by the three-dimensional visualization of the surgical field [1].

Until recently, TORS relied on monopolar electrocautery. It has been shown by Liboon et al. [13] that the acute width of injury for the incisions is greater with monopolar electrocautery than with CO2 laser. However, before hallow wave guides were introduced, CO2 could not be used in TORS because its beam had to be delivered to the tissue in a direct path from the laser tip that is located approximately 40 cm away from the target tissue. This limited the advantages of TORS especially the wide range of movement at the tips of the instruments.

Many attempts have been made to create reliable, safe and effective fiber optic delivery systems for CO2 laser starting with solid-core fibers made of infrared transparent materials to hollow-core fibers using dielectric-metallic film mirror coatings.

At that time a Thulium Laser Fiber was already available, with tissue interaction close to that of CO2, however, the fiber was fragile and was not used widely in the field of ENT [14, 15].

The advances in technology resulted in the development of flexible, mechanically robust, biocompatible, low optical-loss fibers for CO2 lasers that afford reliability and power handling capacity suitable for laser surgery applications. These fibers have been nicknamed omniguide fibers to reflect upon the radiation guiding mechanism by means of omnidirectional mirror structure around the fiber’s hollow core [16, 17]. The first guide was developed by OmniGuide (Boston, MA, USA). It has been used in endoscopic skull base and pituitary surgery, endoscopic sinus and nasal procedures, transoral laryngeal microsurgery, treatment of tracheal stenosis, surgery for glottic and subglottic respiratory papillomas, and office-based respiratory papilloma procedures performed transnasally with flexible endoscopy [18].

Solares and Storme introduced its use with the Da Vinci Surgical system in 2007. They successfully performed a supraglottic laryngectomy for a T4 supraglottic laryngeal tumor on a 74-year-old female. Adequate exposure was achieved with the FK Laryngo-Pharyngoscope, and the tumor was resected in its entirety. The laser setting of 10 W in a continuous wave mode provided the best tissue cutting properties [19].

Since then, the CO2 LWG has been used with TORS in prostatectomy with success [20].

Based on our experience with this series and despite slightly long operative times due to the learning curve needed for the use of a new instrument, we find that the Lumenis Fiberlase WG allows for a very precise cutting, with effective hemostasis of vessels 0.5 mm or less, and is strong enough to support the bending of the tip of the introducer. It does not need to be replaced during a procedure. Its tip can be renewed instantly, if required, using a cutting pencil. It also provides a clear aiming beam that is a significant safety feature.

Conclusion

The CO2 LWG is a reliable, robust tool for TORS. Adding the advantages of CO2 laser to those of TORS will allow easier resection of pharyngo-laryngeal tumors, limiting the thermal effect. Long time follow-up and comparative studies are needed to confirm the role of CO2 LWG in TORS.