Fig. 6.1
Above: 25 gauge needle, 9 cm long, connected Luer-lock to a 20 cc syringe, for the infiltration of anesthetic and vasoconstrictor solution (20 cc of lidocaine 2 %, 0.5 cc of adrenaline 1/1000, 3 cc of one molar watery baking soda, 70 cc of saline solution). Below: 14 gauge Chiba needle, 7 cm long, connected Luer-lock to a 10 cc syringe, for the lipoaspiration
In addition to the absence of incisions in the skin, this makes it possible to obtain a more fluid adipose tissue that slides more easily inside the long flexible needle.
The centrifugation of the lipoaspirate for 3 min at 3000 rpm (according to Coleman’s technique) permits adipocyte concentration, separating it from the serum and the anesthetic and vasoconstrictor solution, which are eliminated. It also concentrates the stromal stem cells contained in the adipose tissue that guarantee the regeneration of the infiltrated laryngeal tissue as well as increasing its volume [13]. In connection with this, we recently also started using PRP (platelet-rich plasma), injected together with the autologous fat into the vocalis muscle and/or alone into the superficial layer of the lamina propria of hypotrophic and/or scarred vocal folds, a technique that is giving promising results [24, 27].
At the end of the autologous fat harvesting (or from the start when using other materials such as hyaluronic acid or calcium hydroxylapatite), the patient is put in a semi-seated position, with his/her head tilted slightly backwards, to facilitate the view of the glottis. The video column is placed by the patient’s head, and the two operators position themselves to the right of the patient (first surgeon) and to the left of the patient (second surgeon or instrument nurse).
6.2.1 Preparing the Instrument Trolley
In addition to the syringes containing the material to inject, the following are positioned on the trolley:
A flexible operating fiberendoscope, which must be short (to facilitate maneuverability), with a working channel of about 2 mm (to allow the introduction of flexible endoscopic needles) and a maximum external diameter of 5 mm (to allow it to pass through the nasal cavity) (Fig. 6.2). The fiberscope must be able to be turned through 180°, without altering the position of the camera, in order to have the working channel always on the side of the vocal cord to be injected. If using a flexible digital endoscope, it must be possible to rotate the image provided by the distal chip camera.
Fig. 6.2
Storz 11001UD1 flexible operative fiberendoscope, operating length 23 cm, external diameter 5 mm, working channel 2.3 mm
A flexible endoscopic needle. We use disposable needles obtained from esophageal varix sclerosis needles manufactured by BTC Medical Europe to our design; they are constituted by a plastic catheter fitted with a metal needle in its distal extremity with 3 different calibers: 19 gauge, 23 gauge, and 25 gauge. The endoscopy needle is housed in a second plastic catheter inside which it slides; consequently, the needle can be locked with the tip protected when the flexible needle is introduced into the operating fiberscope and then locked in an extruded position to perform the laryngeal injection. It is also possible to use an Olympus endoscopic needle, which can have a 19 or 21 gauge caliber and it is contained inside a protective metal catheter. It is important to make sure the needle is retracted into the protective catheter when it is extracted through the fiberscope’s working channel, to avoid damaging it. The flexible endoscopic needle can have three lengths: 60, 80, and 100 cm (Fig. 6.3); the Olympus needles are 105 cm long; it is important to choose the shortest flexible needle compatible with the length of the fiberscope, to avoid wasting the material to be injected (which remains inside the needle at the end of the injection) which, in addition to being precious, can also be expensive.
Fig. 6.3
23 gauge flexible endoscopic needle (De Rossi, Ricci-Maccarini, Borragan, by BTC Medical Europe), left, with the tip retracted into the protective catheter; right, with the tip protruding from the catheter
Laryngeal anesthesia is obtained with lidocaine 2 % followed by 10 % (to reduce the irritating impact on the pharyngeal-laryngeal mucosa), either instilled or administered using the same flexible endoscopic needle (with the needle retracted inside the protective catheter) or with a 1.6 mm diameter resterilizable flexible catheter (BTC).
A high-pressure injection pistol. This is a fundamental tool for fiberendoscopic injection laryngoplasty; after experiments for many years with the various commercial or newly built models, we finally succeeded in devising a pistol that obtains gradual material progression, even in the case of high densities, without the material flowing back into the syringe, and that can be adapted to the position of the needle (which is particularly useful when performing microlaryngoscopic injections) [20]. The capacity of the syringe (3 cc) makes it particularly well suited for intracordal injections of centrifuged autologous fat, given both the quantity and the gradual progression of the material. In this case, we modified the uroplasty pistol usually used to inject polydimethylsiloxane (Vox Implants®), by replacing the pistol tip with a steel adaptor shaped like the tip of the piston on a 3 cc syringe. Instead of a syringe containing 1 ml of polydimethylsiloxane, we introduce a 3 cc polycarbonate disposable syringe whose plastic piston has been removed, keeping the rubber cap, which is applied to the new metal tip of the pistol piston (Fig. 6.4).
Fig. 6.4
Uroplasty pistol for high-pressure laryngeal injection as modified by Ricci Maccarini and De Rossi, with adapter for 3 cc polycarbonate syringe [20]
The material to be injected is poured into the syringe contained in the pistol through a disposable plastic 3-way Luer-lock connector (Fig. 6.5); this prevents the adipose tissue from coming into contact with the air, causing it to oxidize, which promotes a higher absorption of the material injected, therefore making it less stable over time.
Fig. 6.5
Transfer of centrifuged autologous fat into the syringe inside the high-pressure injection pistol (Ricci Maccarini and De Rossi), through a three-way Luer-lock connector
Once the instrument trolley has been prepared, 10 % lidocaine is sprayed into the nasal cavities and oropharynx. The application of nose plugs soaked in anesthetic and vasoconstrictor solution and kept in place for a few minutes before starting the surgical procedure improves anesthetic efficacy and nasal cavity patency, reducing the risk of nasal mucosal tears with consequent bleeding.
The fiberscope is introduced into one nasal cavity (the most patent), aspirating the secretions through the operating canal connected to an aspirator. By means of a resterilizable catheter or protected endoscopic needle, lidocaine is applied to the base of the tongue, in the piriform sinuses, in the laryngeal vestibule, and on the glottic plane; initially lidocaine 2 or 4 % is used, followed by lidocaine 10 %, in order to reduce the irritating effect on the laryngeal mucosa. To test the efficacy of the local anesthesia, the catheter is used to touch the vocal cord to be injected: if the patient does not react and, above all, does not swallow, he/she can be considered ready for the intracordal injection without the risk of him/her swallowing during the injection, which would compromise the result obtained.
At this point, 1 mg of midazolam i.v. is usually administered to prepare the patient for injection laryngoplasty; the dose of midazolam can be increased to 2–3 mg as required, but this dose may not be exceeded to avoid causing a slowdown in breathing with oxygen desaturation and/or dissociation problems that would compromise patient cooperation. Not infrequently, especially in elderly patients, it is sufficient to administer 1 mg of midazolam before harvesting the autologous fat, and it may be possible to avoid using midazolam at all. If the patient complains of nausea, before nausea appears, it is advisable to administer ondansetron hydrochloride i.v.. In some cases, on the other hand, especially in sequelae of partial laryngectomy in which neolaryngeal injection may be painful, it is necessary to be assisted by an anesthetist who will combine opioids with the hypnotic sedative drugs (remyfentanyl) administered by a continuous microdosing pump. This allows perfect analgesia and sedation, making it possible to perform any phonosurgery procedure with a practically immobile operating field, as in microlaryngoscopy under general anesthesia, but, at the same time, with a cooperative patient and therefore with the chance to observe the effects of augmentation and medialization of the injected vocal fold on the patient’s glottic closure and voice.
The operating fiberscope is not grasped at right angles, with the arm facing upwards, as in bronchoscopy, rather, according to the indications of Borragan [8], it is held in a comfortable position with the arm stretching downward, to avoid tiring the shoulder during lengthy procedures (Fig. 6.6). The first operator holds the fiberscope in his/her right hand and with the left controls the fiberscope’s progression inside the nasal cavity or holds it locked in place at the nostril while injecting the larynx. The second operator introduces the catheter for lidocaine instillation into the working channel, prepares the material to be injected by transferring it into the high-pressure pistol, fills the endoscopic needle with the material, inserts the needle into the working channel, and, when the tip of the fiberscope is close to the injection site, extrudes the catheter containing the needle from the working channel, extrudes the needle from the catheter, and introduces it into the injection point (Fig. 6.6).
Fig. 6.6
Position of the operators during fiberendoscopic injection laryngoplasty. The top right-hand box shows the endoscopic picture that appears on the screen when injecting the autologous fat into the right vocal fold fixed in an intermediate position
Otherwise, if the second operator is an instrument nurse (expert), the introduction of the needle is performed by the surgeon, who holds the fiberscope with the left hand and maneuvers the endoscopic needle with the right. This latter technique is particularly well suited for fiberendoscopic phonosurgery procedures involving the removal of vocal fold polyps and other small growths [10].
6.2.2 Technical Details in the Various Indications for Fiberendoscopic Injection Laryngoplasty
6.2.2.1 Unilateral Vocal Fold Paralysis
As described previously, the materials used are autologous fat, slow-resorption hyaluronic acid, and calcium hydroxylapatite.
For autologous fat, a 19 gauge, 21 gauge, or 23 gauge needle is used, as use of a 25 gauge needle causes excessive adipocyte destruction. The 19 gauge needle should only be used when the practitioner is sure that injection will be performed in a single point, as if a subsequent adjacent injection is made; in most cases, the majority of the fat will come out of the large first injection hole.
For slow-resorption hyaluronic acid, a 25 gauge needle is used.
For hydroxylapatite, a 23 gauge needle is used, as the material is very dense; moreover, the endoscopic needle first has to be lubricated by introducing hyaluronic acid (even of the non-cross-linked, fast-resorption type, which is less expensive) until it comes out of the tip of the needle. At the end of the injection, to avoid wasting the expensive material left in the needle (0.5 ml of material in a flexible needle 80 cm long), more hyaluronic acid is introduced, again using the pistol.
The main injection site is the back third of the fixed vocal fold, laterally to the vocal process of the arytenoid cartilage. In addition to get an increase in volume, this maneuver involves a medial rotation with vocal cord adduction. The maneuver to be performed is as follows: once it has been positioned in the back third of the glottis, with the working channel on the side of the fixed vocal fold, the catheter containing the endoscopic needle is protruded, and it is rested against the false vocal fold; the fiberscope is turned 90° toward the posterior commissure of the glottis, directing its tip toward the posterior paraglottic space with downward movements. The needle is protruded and laterally introduced into the vocal process; while the second operator injects the material, the first operator tries to displace the vocal process medially, by pressing on the tip of the fiberscope (and on the tip of the needle inserted into the vocal fold) with an upward movement (Fig. 6.5). The material is injected in excess because, as mentioned previously, fiberendoscopic injection laryngoplasty uses resorbable or partially resorbable materials, and it is therefore necessary to inject at least 1/3 more than the amount needed for normal correction. In actual fact, the injection should be interrupted when the injection site is no longer able to receive further material, to prevent the material leaking from the needle entry hole or from the previous injection hole or from moving toward other sites, such as the false vocal fold or subglottic area.
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