Minimally Invasive Modalities of Salivary Calculus Removal

Symposia to the fact that when compared with parenteral drug administration, the oral route does not offer the same efficacy and safety due to multiple issues relating to drug uptake, duration, and the inability to titrate to effect. Drugs administered per oral (PO) are subject to hepatic metabolism before entering the systemic circulation. A drug’s first-pass metabolism combined with gastric degradation and varied rate of absorption often makes for unpredictable drug bioavailability. Oral agents that may be used to provide anesthesia are often complemented by the use of local anesthesia to provide anesthesia at the surgical site. Additionally, nitrous oxide and oxygen may be helpful in providing additional sedation and analgesia via the inhalation route. Early oral administration techniques involved the use of alcohol in the form of ethanol or chloral hydrate. The introduction of barbiturates as sedative hypnotics led practitioners to use oral secobarbital. Unfortunately with these early attempts at oral anesthesia, the agents’ long clinical duration of action did not permit rapid recovery and efficacy was not predictable. Practitioners have been tempted to consider PO benzodiazepines as anesthetics. Benzodiazepines are effective in producing sedation and a degree of amnesia, but they generally are used in combination with local anesthesia when a painful stimulus is involved. Early use of PO diazepam and alprazolam has been supplanted by the use of midazolam and triazolam. PO midazolam in the pediatric setting has been useful for shorter procedures where the typical onset time of twenty minutes combined with an operative time of twenty minutes is useful. PO triazolam combined with local anesthesia in the adult setting has been useful for longer procedures such as dental operative rehabilitation. With the introduction of ketamine, LSD, and phencyclidine in the sixties, health professionals began using intramuscular (IM) and intravenous (IV) ketamine to rapidly produce an anesthetic state. Ketamine was found to provide profound analgesia, normal pharyngeal-laryngeal reflexes, normal or slightly enhanced skeletal mus-

cle tone, cardiovascular and respiratory stimulation, and occasionally transient, mild respiratory depression. Ketamine was a major advance in the treatment of combative, special needs patients where inhalation and/or intravenous induction of anesthesia was not a reasonable option. Prior to ketamine, these patients were often managed with ‘brutane’ and/or succinylcholine IM. However, it took several decades for practitioners to appreciate that PO ketamine used off label was the only true anesthetic commercially available. Due to the potential for emergence phenomena with the use of ketamine, it is often combined with a benzodiazepine to mediate this response, but ketamine continues to be the sole oral agent that functions as a true general anesthetic. The future of PO anesthetic evolution is interesting from the perspective of what is seen in animal medicine and other countries. The benzodiazepine, flunitrazepam, has infiltrated the United States as the ‘date rape’ drug Rohypnol, which is often combined with ethanol. Carfentanyl, an analogue of fentanyl and 10,000 times more potent than morphine, can incapacitate a lion when just a few drops are given orally. Unfortunately, the Russian government’s use of carfentanyl in a Moscow theater in 2002 to stop terrorists holding hostages had a twenty-one percent casualty rate. Thus, these new oral agents demand careful scientific evaluation to validate their fast onset, efficacy, rapid recovery, and patient safety. References Qureshi FA, Mellis PT, McFadden MA: Efficacy of oral ketamine for providing sedation and analgesia to children requiring laceration repair. Pediatr Emerg Care 11:93, 1995 Auden SM, Sobczyk WL, Solinger RE, et al: Oral ketamine/midazolam is superior to intramuscular meperidine, promethazine, and chlorpromazine for pediatric cardiac catheterization. Anesth Analg 90:299, 2000 Stanley T: Human immobilization: Is the experience in Moscow just the beginning? Eur J Anaesthesiol 20:427, 2003

SYMPOSIUM ON SALIVARY GLAND PATHOLOGY AND OUTCOMES STUDIES Presented on Thursday, September 22, 2005, 10:30 am—12:30 pm Moderator: R. Peter Ward Booth, FDS, FRCS, East Grinstead, England

Minimally Invasive Modalities of Salivary Calculus Removal Mark McGurk, BDS, MD, FDS, FRCS, DLO, London, England Symptomatic salivary gland obstruction has an incidence of 60 cases per million population in the United Kingdom annually. This incidence probably pertains to AAOMS • 2005

the American population which suggests 24,000 new cases each year in the USA. The traditional management of proximal salivary stones is salivary gland removal. In the last decade it has proved possible to miniaturize the instruments successfully used for elimination of renal calculi. This includes extra-corporeal lithotripters, a variety of Dormia baskets and microendoscopes with working channels that will 3

Symposia take miniaturized baskets and forceps for retrieval of stones under direct vision. To complement these developments new surgical techniques have been developed to retrieve stones by leaving a functioning gland intact. Used in combination these techniques can reliably relieve obstruction of salivary glands by stone or stricture and provide an alternative to gland excision for obstructive disease. Experience with gland preserving techniques in a series of 455 patients indicates that in at least 76% of cases stones and obstructions can be eradicated and only 2% of patients required gland removal. This is a radical deviation from current practice. A further advantage is that many of the techniques used in this series can be performed under local anesthetic or on an outpatient basis with low morbidity. The intra-oral removal of submandibular stones can also be undertaken under local anesthetic for appropriate patients but most stones are retrieved on a day case basis under general anesthetic. The scintigraphy results suggest that although gland function improves following treatment it does not return to normal values. However there is accumulating data to show significant gland regeneration following obstruction and with a medium follow-up of 4 years there is no evidence that patients are developing chronic sialoadenitis. Our results as well as others suggest that the optimum management of salivary obstruction should focus on gland preserving techniques. References McGurk M, Escudier MP, Brown JE: Modern management of salivary calculi. Br J Surg 92:107, 2004 Makdissi J, Escudier MP, Brown JE, et al: Glandular function after intraoral removal of salivary calculi from the hilum of the submandibular gland. Br J Oral Maxillofac Surg 42:538, 2004 Zenk J, Iro H: Die sialolithiasis und deren Behandlung. LaryngoRhino-Otol 80:115, 2001

Ultrasound Identification of Salivary Disease Michael P. Escudier, BDS, MBBS, FDSRCS, London, England Extra-oral ultrasonography of the major salivary glands has been widely practiced since the 1970s. Image quality has been greatly improved by recent developments of high resolution scanners designed specifically to image superficial structures. These operate in the range 7.5-20 MHz and have been developed in a variety of shapes and sizes to meet operational requirements. Transcutaneous probes show the normal sonographic appearance of both the parotid and submandibular glands to be similar– homogenous appearance and hyperechoic in comparison with surrounding muscle and fat. 4

The main role of extra-oral ultrasound is in the diagnosis of intrinsic and extrinsic tumors/masses, glandular inflammatory changes, and calculi. The advantages of the technique include its lack of discomfort for the patient, applicability in the acutely inflamed, ease of tumor diagnosis, and avoidance of contrast or ionizing radiation. Color Doppler ultrasound imaging has added a new dimension to the characterization of salivary masses. The main drawback to extra-oral salivary ultrasound imaging is the poor visualization of certain anatomical regions. The deep pole of the parotid suffers from acoustic shadowing from the mandible and mastoid process, making imaging of this area unreliable. Wharton’s duct and the most anterior portion of Stenson’s duct are difficult to detect, thus making these areas relatively blind to transcutaneous ultrasound. These limitations may be reduced by the appropriate adjuvant use of intra-oral ultrasound. This approach requires a smaller size transducer head than would normally be used transcutaneously and higher frequency ranges accompanied by a shorter focal depth to provide improved resolution of superficial structures. References McGurk M: Controversies in the Management of Salivary Gland Disease. Oxford University Press, 2001 Rinast E: Eur J Radiol 9:224, 1989 Howlett D: Br J Radiol 76:271, 2003

Reconstruction of the Palate Following Removal of Palatal Salivary Gland Tumors Andrew E. Brown, FDSRCS, FRCS, East Grinstead, England The majority of palatal salivary gland tumors arise from minor glands towards the posterior aspect of the mouth at the region of the junction of the hard and soft palate. Surgery is the mainstay of treatment for all benign tumors and the majority of malignant tumors. Accurate histology of the lesion is essential in determining the treatment required. Key factors to be considered are the need for palatal bone removal and the degree of distortion, or loss, of the soft palate expected following removal of the tumor. There has been debate in the literature concerning the role of palatal fenestration in the management of palatal pleomorphic adenomas but this is generally contra-indicated except in larger tumors, or where there is definite evidence on sectional imaging of a breach in the bony integrity. Malignant tumors will almost certainly require palatal fenestration to obtain clearance and intermediate tumors have to be judged on their individual features. If the palate is fenestrated a decision has to be taken between prosthetic obturation and reconstruction. The risks and benefits of both modalities will be briefly conAAOMS • 2005