Introduction
The introduction of sialendoscopy into clinical medicine and its combination with other treatment modalities has led to a pronounced change of treatment during the last 25 years. Development of new sialendoscopes and various microinstruments has been significant for the introduction and establishment of new minimally invasive operative techniques for the treatment of sialolithiasis. While small, mobile stones with a size of 3–5 mm can be retrieved primarily by various instruments with success rates of >85% , these make up only 15–20% of all stones. In over 80% of stones, prior fragmentation by intracorporeal shock wave lithotripsy (ISWL), extracorporeal shock wave lithotripsy (ESWL) is necessary or transoral duct surgery, or combined approaches has to be performed due to stone size, impaction, and location. ISWL is indicated for stones accessible with the sialendoscope with various methods of intraductal fragmentation available. If properly selected, these modalities can be applied with high success rates of more than 90%. The size of the stone is associated with impaction, the location may determine the accessibility of the stone with the sialendoscope, and the consistency pertains to method of fragmentation. Mechanical fragmentation can be achieved by microdrills or forceps of different sizes (0.38–0.78 mm). The stone is fragmented by shear, rotational, and pressure movements. It is generally suited only for stones with maximal size of 7–8 mm with a softer consistency. In laser lithotripsy (LT), the energy of the laser light is transmitted by a glass fiber directly onto the surface of stones in near contact and/or contact modus. The emitted energy causes vaporization and/or fragmentation. Stones, which are hard, hyaline stones with a high ratio of mineralization, are more suited for this kind of lithotripsy. Results after application of different laser types have been published for over 15 years. Acceptable results with constant success rates of >80% were reported with the use of the Ho:YAG laser. Different modifications of kinetic or ballistic lithotripsy are electrohydraulic lithotripsy (EHL), electrokinetic lithotripsy (EKL), and pneumatic lithotripsy (PL). In all applications, the energy is transmitted to a probe resulting in kinetic energy, which is transmitted onto the surface of a stone causing fragmentation. All of these are associated with the potential disadvantage of mechanical trauma to the tissue (e.g., duct perforation) and propulsion of stones into the proximal/intraparenchymal duct system or into the periductal tissue. Although effective, risks and costs of EHL and EKL are not favored currently.
Pneumatic Lithotripsy
Alongside intraductal LT (see Chapter 22 ), intraductal pneumatic lithotripsy (IPL) represents the most effective method of ISWL. In IPL, gas, mostly CO 2 gas, is the source of energy. The pneumatic energy is transmitted to a probe resulting in kinetic energy, which is transmitted onto the surface of a stone. Direct contact to the stone is necessary to cause fragmentation. The gas can be released out of a central connecting system or out of a cartridge. Several devices are used to perform IPL. Arzoz et al. treated 18 patients with sialolithiasis, nine of these with IPL (Lithoclast; EMS Swiss, Nyon, Switzerland). The overall success rate was 80%. The gland preservation rate was 89%. Serbetci and Sengor reported on the treatment of two patients with IPL (Calcusplit; Storz, Tuttlingen, Germany). In one of two cases, complete fragmentation and a stone-free state was achieved.
At the beginning of 2015, a new device for the performance of IPL was introduced to fragment salivary stones (StoneBreaker; Cook Medical, Bloomington, IL, USA). It is a small and lightweight handheld device ( Fig. 23.1 ). Due to the integrated gas cartridge, the device is independent from immobile gas resources. The pneumatic energy is released by a trigger mechanism and can be transmitted by an exchangeable nitinol probe (diameter 0.56 mm) under direct endoscopic control onto the surface of a stone. The application is, like all other methods of intraductal fragmentation, dependent on the accessibility of the stone with an adequate sialendoscope. In a recent publication, 44 patients with 49 stones were treated with this device (19 submandibular and 23 parotid glands; Figs. 23.2–23.4 ). In 40 patients, one stone was present; in three patients two stones; and in one case, three stones were treated. In 98%, complete fragmentation (96% of submandibular and 100% of parotid stones) was achieved. Some 98% of the patients became stone-free (100% of submandibular and 95% of parotid glands). All patients became complaint-free. Complete success was achieved in 98% (100% submandibular and 95% parotid glands). In 100% of patients, gland preservation was achieved. In five patients (11.4%), additional treatment methods were necessary to reach this success rate (in two patients, transoral duct surgery – all in submandibular glands; in three patients, ESWL was required – one submandibular and two parotid gland). The efficacy, duration, and number of procedures necessary to achieve successful treatment by this method appears similar to all other modalities of intraductal lithotripsy. It is dependent on the size and location of the stone, but also on the anatomic relationships of the salivary duct system.
