Anatomic surgery for salivary calculi

Oral SURGERY VOLUME

Oral MEDICINE

NUMBER AND&d

JULY,

PATHOLOGY

26 1 1968

Operative oral surgery

Anatomic surgery for salivary calculi Part VI.

Calculi

in the intraglandular

G. R. Seward, M.D.S., F.D.X.R.C.X., THE

LONDON

HOSPITAL

MEDICAL

part

of the parotid

duct

M.B., B.S., London, England

COLLEGE

I

f a calculus is not found on a periapical film applied to the inside of the cheek or on a posterior oblique occlusal radiograph, then it is either radiolucent or lies behind the accessory parotid gland. Should the accessory parotid remain unaffected when the rest of the gland is swollen, then the obstruction is either within the gland or in that part of the duct which lies between the main gland and the accessory parotid. If, during an attack of swelling, only the lower pole becomes enlarged (Fig. 40,A), then the obstruction is definitely in the intraglandular course of the duct. Where an inflammatory swelling appears to affect part of the parotid gland, however, it must be borne in mind that the swelling might be due either to the preauricular lymph nodes or to the upper members of the deep cervical lymph nodes which lie in the lower pole of the parotid. It can be quite difficult to differentiate clinically between an inflammatory swelling of part of the gland and Marned lymph nodes. A differentiation also has to be made between parotid calculi and other calcified objects in the same region. Phleboliths in a cavernous hemangioma of the cheek are quite like salivary calculi in that they appear concentrically laminated in radiographs. They are usually multiple, however, and can be shown both by 1

O.S., O.M. & 02.

2 Seward

July, 1968

their position and by sialographic studies to be outside the parotid. In q&icercosis, calcified parasites are occasionally seen in the soft tissues of the face, but, again, the small oval calcifications are multiple. Calcified tuberculous lymph nodes are more common in the submandibular region, but they can OCCUR near the parotid region where they could be confused with parotid calculi. The differentiation usually is not difficult, as the calcified node is much larger than most parotid calculi, and the calcified mass is composed of an aggregate of calcified spicules and has a different appearance from a salivary calculus. Rarely, tonsoliths are seen in an oblique lateral projection, but here differentiation is easy, as in the posteroanterior view they can be seen to be medial to the jaw. Plain radiography for calculi within the intraglandular part of the parotid duct can be difficult. In oblique lateral views the calculus is likely to be obscured by the ramus of the mandible. In the off-centered anteroposterior or posteroanterior film, the type of exposure that will record the image of a calculus will produce such marked images of the soft tissues that these, again, may mask a calculus (Fig. 34). The special tangential view with the cheek blown out, which Stafnel devised, has some advantages; nevertheless, like the posteroanterior and off-center posteroanterior views, it casts a heavy soft-tissue shadow. Thus, many intraglandular calculi which are, in fact, calcified are not found by plain radiography. Therefore, a sialogram is often necessary to demonstrate the presence of a calculus as well as to show its position in the gland (Fig. 35).

A

Fig. 34. A, Plain Sh8 sped shadow. B, A Pa’ :otid duct, probably

posteroanterior radiograph showing a sizable parotid calcub x3 as a ringsialogram of the same atient confirms that the calculus is in the mam within the boundaries o% the gland.

Anatomic Operative

surgery

for

salivary

calculi

3

procedure

The hair in front of the ear is shaved up to the level of the top of the pinna, and the skin is prepared in the usual manner. In order to reduce capillary bleeding, the subcutaneous tissues over the gland are infiltrated with a solution of one part Adrenalin in 240,000 parts of normal saline solution. The external auditory meatus is lightly plugged with sterile cotton wool. The incision starts within the hairline and passes obliquely downward and backward to the pinna. It skirts the attachment of the upper part of the pinna, passes across the free edge of the tragus, follows the attachment of the lobe of the ear, and then curves round beneath the lobe to join a neck crease, finally passing downward and forward across the posterior part of the sub-

Fk’. 85. a, An example of a 30 degree occipitomental radiograph of a right parotid sialogram showing a cakulus. B, A lateral view of a sialogram of a right parotid gland showing the outline of a large radiolucent calculus in the main duct. The calculus is intraglandular i,u position, opposite the posterior border of the ramus of the mandible.

4

Seward

F ‘is.

36

F‘is.

38

O.K.

O.M. & 0.1’. .Tuly, 1968

E

Fig. 36. Photograph showing the incision used for removal of intraglandular parotid calculi. The flap has been dissected from the surface of the parotid sheath and sutured forward onto the cheek. Fig. 37. The deep fascia has been incised in line with the duct at a point anterior to the gland. The edges of the fascia have been retracted with silk stay sutures, exposing the duct. Note the branch of the facial nerve which lies on the surface of the duct. A silk thread has been passed under the duct. Fig. 33. The duct has been traced backward through the gland as far as the calculus. It has been incised, and the calculus is being removed. Towels have been sewed to the wound edge to isolate it from the surrounding regions. Fig. 39. Closure of the incision. The photograph shows how it has been placed to conform to local skin creases. A vacuum drain emerges through the skin behind the ear.

39

Volume Number

26 1

Anatomic

surgery for salivary

calculi

5

mandibular region (Figs, 36 and 39). The flap is raised over the surface of the upward extension of the investing layer of deep cervical fascia, which in this region forms the capsule of the parotid gland (Fig. 36). Inferiorly the knife is carried over the surface of the platysma, and anteriorly the dissection passes onto the surface of the deep fascia which covers the buccal space, the fascia here being continuous with both the edge of the platysma aad the capsule of the parotid gland. As the upper and anterior borders of the parotid gland are approached, the operator should watch carefully for the branches of the facia.1 nerve which supply the frontal part of the oceipitofrontalis and the upper part of the orbicularis oculi. These particular branches lie more superficially in the tissues than the other branches, passing between the layers of the deep fascia in this region rather than beneath it. Once the reflection has been carried to just beyond the anterior border of the parotid, the flap is folded forward and tacked onto the cheek with two loosely tied sutures (Fig. 36). Tetra towels can be sutured to the margins of the wound at this stage, It is best to identify the duct at the point where it emerges from the anterior border of the gland. The fascia is incised in line with the duct, and a gentle search is made. A useful guide is the surface marking for the duct, which is the middle third of a line which runs from the tragus of the ear to the midpoint on a line which joins the ala of the nose to the angle of the mouth. The normal duct is pinkish gray in color and has fine blood vessels branching over its surface. In this region a branch of the facial nerve which supplies the upper lip is frequently found lying on the surface of the duct (Fig. 37). In the uninflamed state there is a layer of loose connective tissue about the duct, but if there have been several attacks of acute infection it may be adherent and more difficult to find. Should the transverse facial vessels be seen, it should be remembered that they lie about 1 cm. above the parotid duct. In plump subjects, lobes of fat can accumulate in this region, apparently in relationship to branches of the facial nerve and small blood vessels. They can have a cylindrical shape and, with a thin covering of loose connective tissue, can appear remarkably like the parotid duct, particularly since, in such patients, the connective tissue covering the duct itself may be filled with fat. In cases of doubt the structure can be incised longitudinally and explored to see whether it has a central lumen. For cases in which difficulty in identification of the duct is anticipated, the insertion of a sterile, flexible, gum-elastic, filiform bougie into the duct before the operation has been tried. The bougie can be palpated through the wall of the duct, and this makes the identification easier. There would seem to be two possible objections, however, to using this technique routinely. First, the bougie acts as a possible pathway by which infection from the mouth can ascend to the gland at a time when salivation is suppressed by the premeditation. Second, the bougie could easily displace the calculus backward into a less accessible part of the duct. The first’ objection can be overcome by careful preparation of the mouth

6

Xewaro?

O.P., O.M. & 0.X’. July, 1968

A

B

photograph of a patient Fig. 40. A, Preoperative lower pole of the parotid only. B, Postoperative view of the swelling. Note inconspicuous scar.

with a calculus causing swelling of the of the same patient, showing resolution

before the operation. Two Hibitane pastils (brand of chlorbenidine lozenges) are sucked, one 2 hours and the other 1 hour before the operation. Finally, just before the patient goes to the operating room, a Hibitane mouthwash is used to remove any possible fragments of the pastils which might still be in the mouth. In addition, if the end of the bougie is taped to an easily accessible part of the face, under the towelling, the anesthetist can withdraw it as soon as the duct is identified. The second objection can be overcome by insertion of a measured length of bougie, just sufficient to reach the anterior border of the gland. Once the duct has been identified, it can be traced backward into the gland (Fig. 38). Patient separation of the gland lobules by division with fine pointed scissors of the delicate connective tissue which joins them together is the best way to proceed. Special care should be taken to avoid damage to branches of the facial nerve which, if they cross the duct, do so in contact with its outer aspect. Care should also be taken with tributaries of the posterior faeial vein. If possible, they should be picked up with artery forceps before they are divided, since once the tissues have suffused with blood, it is more diEcult to see certain structures. Silk sutures passed through the edge of the wound in the gland form the best retractors. Once the calculus-bearing part of the duct has been uncovered, the usual longitudinal slit is made in the wall to release the caculus (Fig.38). The duct

Volume Number

Anatomic

26 1

surgery

for salivary

calcdi

7

is gently irrigated with saline solution and sucked out, so as to ensure as far as possible that no additional small calculi are present. The gland proximal to the opening should also be massaged to express some saliva into the duct. This, again, should help to remove any other additional calculi. Should this last maneuver produce purulent saliva, the irrigation a.nd massage should be continued until no more pus is seen. Finally, all the retraction sutures are removed. The incision in the duct is not repaired, but the capsule of the parotid is closed with a 5-O continuous catgut suture. A few interrupted catgut sutures are placed in the subcutaneous tissue, and the skin is closed with interrupted silk sutures (Fig. 39). A drain is needed for 24 hours to prevent hematoma formation, and this may be either a piece of corrugated rubber inserted through the incision where it passes behind the lobe of the ear or, if the wound can be made airtight, a vacuum drain passed through the lower flap (Fig. 39). A firm pressure should also be applied. Because the gland proximal to the stone is usually clinically infected, systemic antibiotics should be administered for 5 days postoperatively. For the same reason, the affected part of the gland may remain swollen for a month or two afterward, if it was swollen before the operation, but obviously there should- be no additional swelling at mealtimes. There should be no facial weakness, but there will be anesthesia of the skin which has been undermined in raising the flap. This usually disappears in 2 to 4 months, the return of sensation creeping in from the periphery of the area. The operation just described may seem a sizable procedure for a small calculus, but the scar is inconspicuous (Fig. 40) and if, by removing the aalculus, chronic infection of a gland is avoided, it is very worth while. REFERENCE

1. Stafne, E. C.: Oral Company, p. 132.

Roentgenographic

Diagnosis,

ed. 2, Philadelphia,

1963,

W. B. Saunders