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Anatomic surgery for salivary calculi
Anatomic surgery for salivary calculi Part IV. Calculi
in the intraglandular
G. R. Seward, M.D.S., P.D.X.R.C.X., THE
W
LONDON
HOSPITAL
MEDICAL
part
of the submandibular
duct
M.B., B.S., London, England
COLLEGE
ithin the submandibular gland the main duct takes a sharp turn downward and receives the first of the secondary ducts. This one commonly drains the upper pole of the gland and slopes downward and forward to enter the back of the main duct. The duct which drains the deep part of the gland passes backward parallel to and below the main duct to enter the front of the main duct just below the sharp turn. Calculi which lie in the region of the sharp curve in the duct are intraglandular. Where the calculus completely blocks the duct, it may be difficult to estimate its position, even from the sialogram, as not enough of the curve may be outlined for the relationship of the calculus to this landmark to be judged. Under these circumstances, if one or both of the two secondary ducts mentioned above are filled with contrast medium, the intraglandular position of the calculus is confirmed. The manner of presentation of patients with intraglandular calculi is similar to that of patients with stones posteriorly in the extraglandular part of the main duct, and the investigations used are the same. The sialogram is obviously of particular importance, not only to demonstrate the intraglandular position of the stone but also to give an indication of the degree of damage suffered by the gland. When the plain films are reviewed, one must not overlook the possibility that several calculi may be present, particularly a small anterior calculus. While it may be possible on occasion to remove large intraglandular calculi through an incision in the floor of the mouth, this is, in general, a difficult procedure and one which cannot be undertaken with complete confidence of success. The chances of retrieving a small calculus are even smaller. One type of case in which such an attempt is indicated is that of a young woman with a particularly creasefree neck. The method is essentially the same as that used for the removal of calculi which lie posteriorly in the extraglandular part of the duct, but if this procedure is adopted it is as well to warn the patient that there is a chance that it might not succeed. In general, where it is established that a calculus lies in the intraglandular
part of the duct, the entire gland should be removed. Should the calculus be a chance finding, however, if it is not causing symptoms and is small and if the gland is sialographically normal, then it may be left for a while and kept under observation to see if the calculus will move forward into a more accessible position. An occasional sialogram should be performed to check that the gland is remaining comparatively healthy. Obviously, if the first sialogram shows gross damage to the gland, this in itself requires excision of the gland. INTRAORAL
OPERATIVE
PROCEDURES
If removal of the calculus via the mouth is attempted, one or two anatomic fcaturcs should be borne in mind. The facial artery emerges from under cover of the stylohyoid muscle and passes upward and forward on the deep surface of the gland. The general direction is around the upper and posterior aspects of the gland, the artery finally turning downward on the superficial surface of the gland in order to reach the lower border of the mandible. It commonly passes either in a deep groove in the gland or through the substance of the gland to reach the superficial surface. In some cases the artery merely curves around the gland in a shallow depression and is in jeopardy from a generous incision in the upper pole. It is therefore preferable to raise the duct and incise the front of the gland immediately below the point of exit of the duct. In any case, such an incision is also more likely to open the duct where it starts its downward curve than one made into the top of the gland. A second point t,o remember is that the veins from the gland which drain into the anterior facial vein emerge from the substance of the gland in the region of the lower horder of the mandible and are relatively short. To avoid tearing these veins, vigorous att.empts to mobilize the gland should not be made through the mouth. Were the veins to be torn, a. considerable hematoma would result. Indeed, if one of these tributary veins were to be avulsed from the anterior facial vein, the bleeding could be difficult to control. Although normally t,he subma,ndibular salivary gland is removed through an incision in the submandibular skin, Downton and Qvistl have described a method of removing the gland through an int,raoral incision. They observed that, during their operation for removal of the mylohyoid ridge in edentulous patients, a good view of the gland was obtained. The.refore, they have removed the gland ihrongh a similar incision. There would appear to be a number of difficulties in this i cchniqllc. The origin of the mplohpoid muscle is ISS easy to tletnch in :he yonng subject with teeth still present 111~~1 in the cdentuhus p~~xon, and. !I, t.11 II1
iil,lCl'
~wrYc~l!s.
titP
Pllt
lllyi(~ily(~i~‘/
P?d$P t?J?dS
to
tK!zC.
~+2iJl,
ligittioJ3
Of
:.CSsels supplying fllc ~lillld clcptndn on thc41* elasticity arid the rlcgiW' lo which they can be dlclivered int,o the wound. If thep arc not adequatrly c’ontrolled, a. considerable hematoma can result. This is untiol&t,c~tIly an opcrat,ion to be performed by those with special experience. 1hc bloid
EXCISION
OF THE SUBMANDIBULAR
SALIVARY
GLAND
The operation for remora1 of the submandibular salivary gland is well known and has been described, for example, by Pat,ey.4 The skin is prepared in the
O.S., O.M. & O.P. May, 1968
usual way, and an incision is mapped out over the submandibular gland. The line of the incision should be in or parallcl to the skin creases and approximately 1.5 cm. below the lower border of the mandible. That is about one third of the way up from the lower pole of the gland to the lower border of the mandible. An incision about 2 inches long is sufficient.. It is helpful to inject a solution containing 1 part Adrenalin in 240,000 parts normal saline into the subcutaneous tissues and beneath the platysma over the arca of operation. If such an injection is made, then the outlining of the incision is particularly useful, as the solution distends the tissues and masks the anatomic landmarks. Provided an Adrenalin solution is injected and the table is tilted, head upward, enough to reduce the pressure in the superficial veins, then an almost bloodless field will be obtained, facilitating a precise dissection. The incision is made down to the platysma (Fig. 19). Pressure with a swab, first on the fat of the upper wound margin and then on that of the lower, will strip the subcutaneous layer off the platysma for a short dista,nce. This maneuver aids closure of the wound in layvers. If a pair of large straight scissors is opened in the sa,me plane at each end of the wound, then the extremities of the wound
Fig.
19
Fig.
20
Fig. 19. The skin incision showing how the subcutaneous tissues can be separated from the surface of the platysma to facilitate the repair of the wound in layers. Fig. $0. The platysma muscle has been incised, exposing the deep fascia which, in this subject, was composed of a single, thick sheet.
are similarly undermined and the incision in the fat can be completed with the same scissors to the full extent of the skin incision. The platysma is divided next and, if an adhesive drape has not been applied, tetra towels are sewed to the wound margins wit,h horizontal mattress sutures (Fig. 20). The investing layer of deep fascia in this part of the neck may be of two types. Tn many persons? particularly women, it is composed of a number of closely applied lamina.e, each of which is quite delicate. In others it is a single, tough, gray-white sheet (Fig. 20). The fascia is best opened by lifting it in the center of the wound with forceps and snipping it with scissors. The scissors can be inserted through the open-
Fig.
i
21
.-“,.Lli
urn, the &eep f&a &as 61% incised and reflected; one part fascia is gripped by the left hand artery forceps, and t,he 1 of I latysma are seen at B. The mandibular branch of the facial -in cW31 ning on its surface, is seen at C; the submandibular saliva1 a n la; If loose connective tissue, is revealed at the anterior end of the wou sh tat l>Ftph node of the submandibular group lying on the ant
O.S., O.M. & O.P. May, 1968
ing and slid laterally to define the individual layers before the opening is extended to the extremities of the wound. The angular tract of fascia is a thickening in the investing layer of deep fascia which spreads downward from the stylomandibular ligament and the angle of the mandible, and it may be encountered as the deep fascia is opened toward the posterior end of the incision. From the deep surface of the investing layer in the region of the angular tract, a sheet of fascia turns medially behind the submandibular gland a,s part of the wall of its fascial compartment. This fascia also passes medially and posteriorly toward the external carotid artery and the internal jugular vein. As the posterior part of the fascial incision is extended, therefore, it is important to separate a layer parallel to the surface, lest the scissors be deflected toward the deeper parts of the neck. The branches of the facial nerve are distributed deep to the platysma. Sometimes they are encountered between the platysma and the deep fascia,, but more often at the level of this incision they are found deep to the deep fascia and loosely applied to its deep surface; hence, the care which should be taken over the division of the deep fascia. Slender branches can be spotted by the tiny blood vessels which run along their length (Fig. 21). The course of the mandibular branch of the facial nerve is variable, and it may pass in a loop quite a distance into the neck.2 Although normally said to recross the lower border of the mandible at the facial vessels, in fact, it can be found below the mandible as far forward as the premolar region. Should a branch of the nerve pass obliquely across the wound, it is best managed by freeing the nerve from the deep surface of the margins of the wound to a point either anterior or posterior to the incision. The nerve can then be held back by means of a retractor applied to one of the wound edges. At this stage, if the edges of the incision are retracted, the anterior facial vein will be seen embedded in the loose connective tissue which surrounds the submandibular gland (Fig. 21). The vein is isolated and divided between ligatures. The upper flap is raised by dividing the connective tissue close to the surface of the gland with scissors, the plane of dissection passing deep to the anterior facial vein. This will ensure that any branches of the facial nerve in the upper flap are raised with the flap, particularly as the mandibular branch of the nerve may pass back above the lower border of the mandible superficial to the vein and at the point where the vein leaves the mandible.3 If the arterial supply to the gland is secured next, the venous engorgement of the gland and the oozing which follow ligation of the anterior facial vein are reduced. To find the facial artery, the lower pole of the gland is dissected up with scissors and then mobilized by finger dissection. A pair of Allis forceps is applied to the posterior border of the lower pole and the gland is turned upward and forward (Fig. 22). The posterior belly of the digastric muscle, with the stylohyoid muscle on its anterior surface, is identified, and a retractor is placed to draw them downward and backward. By separating the loose connective tissue in the interval between the gland and the muscles, the facial artery is exposed. It emerges from behind the stylohyoid muscle and passes upward and forward to
Volume 25 Number 5
Ana,tomic
surgery
for salivary
calczcli
675
Fig I. $4
Fi ig. 63. The gland has been separated from facial artery is exposed where it emerges onto again at this pail 1t. B?ig. 34. The : anterior border of the gland which is she,W?Il at A. The groove between the lvlearl. y seen Inow that it has been separated from facial artery runi 3 forward just above the muscle.
the lower border of the man diblr, and the the outside of the mand ible. It is divided has been freed from the mylc jhyoid muscle, superficial and deep part .s of the gland is the muscle. The submandit branc h of the
enter the deep surface of the gland, and it is frequently accompanied by venae comitantes at this site (Fig. 22). The facial artery may be ligated with the aid of an aneurysmal needle, or it may be clamped kth artcry forceps, divided: and ligated. If the latter course is adopted, it, is advisable to apply t.hree pairs of forceps, dividing the artery ~JdWc1i fhc histal two pairs. Then: if tht: ligatnrc applied below the first of the t~roximal pairs of forceps should break or slip, the artery will he controlled by the second pair. The reason for this cautious treatment of the artery is that mobilization of the gland draws it out from behind the muscles, and as soon as the proximal end is released it retracts out of sight. Thus, should the artery be released before it has been properly liga.ted, the bleeding point could be difficult t.0 find. The course of the facial artery varies between patients. It may emerge from behind t,he stylohyoid muscle at a low level and penetrate deeply into the gland
OS., O.M. & OP. May, 1968 in order to re:tch the upper pole, or it may emerge high up and merelg groove the gland. In the second instance, the artery hardly ascends at all on t,he deep surface of the gland but passes a,lmost horizontally forward before turning downward so as to emerge between the gland and the lower border of the mandible. Low a.rtcries arc easy t,o ligate behind the lower pole of the gland, but high a.rtcrics can be difficult to reach from this aspect. Fortunately, it is the low arteries which are the most likely to be deeply embedded in the gland, since it is under these c,ircumstanccs that the vessel is best dealt with by ligation and division both above and below the gland. High arteries should bc left until the dissection has proceeded sufficiently to allow the gland to be drawn down and the artery to be separated from ibs groove with division of the short glandular branches. The upper flap with the anterior facial vein is retracted and the interval between the lower border of the mandible and the gland is defined. As the lower border of the mandible is approached, a number of venous tributaries will be encountered passing from the gland to the anterior facial vein; also, a number of small glandular vessels from the submandibular artery and vein will be found. Once these have been divided, the gland can be separated from the mandible and the facial artcry will be seen once more, hooking around the mandible to join the anterior facial vein. If the artery has been divided below the gland, then it should be divided again at this point (Fig. 23). The operator should now turn to the anterior border of the superficial part of the gland and transfer the Allis forceps to the ant,erior aspect of the lower pole. Reflecting the anterior border upward and backward exposes the groove in the gland in which the posterior border of the mylohyoid muscle fits (Fig. 24). The muscle is quite firmly and closely applied to the groove in the gland. As the scissors divide the connective tissue which binds the two together, a few small blood vessels which enter the gland from t,he muscle will be divided as well. A finger can now be passed up under the gland so as to lift it from its bed. Finger dissection is augmented where necessary by scissor dissection, with the tips of the scissors kept close against the surface of the gland. By keeping close to the gland, a covering of loose connective tissue is left over the hypoglossal nerve, which lies in a curve diagonally across the underlying hyoglossus muscle (Fig. 26, A and B). It is worth while, as the middle of the medial aspect of the gland is freed, to look out for a vein which is sometimes present (Fig. 26, B). It runs from the gland into the lingual veins which are deep to the hyoglossus. Should the vein be divided before the distal end has been secured, it will retract through the hyoglossus and produce a troublesome hematoma. By using the finger once more as a blunt dissector, the upper part of the posterior border can be freed, whereupon the gland can be drawn downward. Sometimes a particularly tough strand of fascia is attached to the posterior end of the upper pole. If it is present, great care should be exercised in dividing it lest the lingual nerve should be damaged. As the gland is pulled downward, a V-shaped fold of connective tissue comes into view, attached to the upper pole of the gland. It contains both the lingual nerve and the submandibular duct (Fig. 25, A). If they are dissected out with
T’olume 25 Sumher 5
Fig.
65
Fig.
dfi
bringing the s LO& The gland has bringi>. aabbeen mobilided sui?kiently to draw it do&&d, ,W W,U view. YIW. The LW arrow points to the sublingual gang:‘~~u. Right, nq~tts, The .tna lingual n~rvc 10 into ganglion. unner pole wle of the gland and has been displaced disolaced upward unwz en separated from the upper so le the duct of the th’ submandibu1a.r me gland (B), the duet contains two calculi, vvhich I shining through its llru wall. tYyall. The root of the sublingual ganglion is seen Illlz posterior y”uwL’“’ l”“L “L Lilt! auuutL#um,l g”Jqp”u 1: nerve where it crosses the duct, but the ganglion itself is now hidden by the deep gland, which is passing upward anterolateral to, and parallel with, the duct. seen, with the muscles covered by a thin IayFig. %6. Left, The gland bed as it is normally muscle. Right, The counective tissue er 0 f tonne etive tissue: fC) is the tendon of the digastric has been re moved from part of the gland bed so that, a small vein which passed from the deep It is seen clamped by the surf !ace of the gland through the hyoglossus could be controlled. nerve (A) has been uncovered where it passes upward and ah? ‘ry fnrc eps. The hypoglossal tendon (B) divides at this point to embrace the for1 vard *t-l cr the hpoglossus. The stylohyoid digi mtrie.
O.S., O.M. & O.P. May, 1968
care, t,he sublingual ganglion may be seen, applied to the upper pole of the gland, just behind the point at which the duct emerges (Fig. 25, A). Once the nerve has been separated from the gland and the duct, it can be pushed upward quite easily, thus exposing the duct well beyond the point at which the nerve normally passes under the duct to reach the tongue (Fig. 25, B) . Only the duct and the deep part of the gland now attach the gland. A retractor is hooked over the posterior border of the mylohyoid so as to expose the deep part; before the delicate connective tissue which attaches it is divided, however, a pair of artery forceps should be applied just beyond its anterior end. A small artery, which probably originates from the sublingual artery, frequently enters the deep part of the gland at this site. Further traction on the gland will now enable the operator to clamp, divide, and ligate the duct so that only a short stump is left, just enough to drain the major sublingual gland and any posterior sublingual gland which empties into the submandibular duct. The wound is carefully inspected, and any further bleeding points are ligated. A vacuum drain is passed from the gland bed out through the lower flap, and the wound is carefully closed in layers. REFERENCES
1. Downton, D., and Qvist, G.: Intra-Oral Excision of the Submandibular Gland, Proe. Roy. Sot. Med. 53: 543-544, 1960. 2. Faber, M., Van Vooren, P., and Libersa,, C.: Disposition anatomique des branches sousmandrbulaires du nerf facial, Rev. stomato-odont. N. Fr. 16: 143-147, 1961. 3. Last, R. J.: Anatomy-Regional and Applied, ed. 2, London, 1959, J. & A, Churchill, Ltd., p. 491. 4. Patey, D. H.: In Rob, C., and Smith, R. (editors) : Operative Surgery, Vol. 4, Part IV, London, 1957, Butterworth & Co., pp. 149-151.
in the intraglandular
G. R. Seward, M.D.S., P.D.X.R.C.X., THE
W
LONDON
HOSPITAL
MEDICAL
part
of the submandibular
duct
M.B., B.S., London, England
COLLEGE
ithin the submandibular gland the main duct takes a sharp turn downward and receives the first of the secondary ducts. This one commonly drains the upper pole of the gland and slopes downward and forward to enter the back of the main duct. The duct which drains the deep part of the gland passes backward parallel to and below the main duct to enter the front of the main duct just below the sharp turn. Calculi which lie in the region of the sharp curve in the duct are intraglandular. Where the calculus completely blocks the duct, it may be difficult to estimate its position, even from the sialogram, as not enough of the curve may be outlined for the relationship of the calculus to this landmark to be judged. Under these circumstances, if one or both of the two secondary ducts mentioned above are filled with contrast medium, the intraglandular position of the calculus is confirmed. The manner of presentation of patients with intraglandular calculi is similar to that of patients with stones posteriorly in the extraglandular part of the main duct, and the investigations used are the same. The sialogram is obviously of particular importance, not only to demonstrate the intraglandular position of the stone but also to give an indication of the degree of damage suffered by the gland. When the plain films are reviewed, one must not overlook the possibility that several calculi may be present, particularly a small anterior calculus. While it may be possible on occasion to remove large intraglandular calculi through an incision in the floor of the mouth, this is, in general, a difficult procedure and one which cannot be undertaken with complete confidence of success. The chances of retrieving a small calculus are even smaller. One type of case in which such an attempt is indicated is that of a young woman with a particularly creasefree neck. The method is essentially the same as that used for the removal of calculi which lie posteriorly in the extraglandular part of the duct, but if this procedure is adopted it is as well to warn the patient that there is a chance that it might not succeed. In general, where it is established that a calculus lies in the intraglandular
part of the duct, the entire gland should be removed. Should the calculus be a chance finding, however, if it is not causing symptoms and is small and if the gland is sialographically normal, then it may be left for a while and kept under observation to see if the calculus will move forward into a more accessible position. An occasional sialogram should be performed to check that the gland is remaining comparatively healthy. Obviously, if the first sialogram shows gross damage to the gland, this in itself requires excision of the gland. INTRAORAL
OPERATIVE
PROCEDURES
If removal of the calculus via the mouth is attempted, one or two anatomic fcaturcs should be borne in mind. The facial artery emerges from under cover of the stylohyoid muscle and passes upward and forward on the deep surface of the gland. The general direction is around the upper and posterior aspects of the gland, the artery finally turning downward on the superficial surface of the gland in order to reach the lower border of the mandible. It commonly passes either in a deep groove in the gland or through the substance of the gland to reach the superficial surface. In some cases the artery merely curves around the gland in a shallow depression and is in jeopardy from a generous incision in the upper pole. It is therefore preferable to raise the duct and incise the front of the gland immediately below the point of exit of the duct. In any case, such an incision is also more likely to open the duct where it starts its downward curve than one made into the top of the gland. A second point t,o remember is that the veins from the gland which drain into the anterior facial vein emerge from the substance of the gland in the region of the lower horder of the mandible and are relatively short. To avoid tearing these veins, vigorous att.empts to mobilize the gland should not be made through the mouth. Were the veins to be torn, a. considerable hematoma would result. Indeed, if one of these tributary veins were to be avulsed from the anterior facial vein, the bleeding could be difficult to control. Although normally t,he subma,ndibular salivary gland is removed through an incision in the submandibular skin, Downton and Qvistl have described a method of removing the gland through an int,raoral incision. They observed that, during their operation for removal of the mylohyoid ridge in edentulous patients, a good view of the gland was obtained. The.refore, they have removed the gland ihrongh a similar incision. There would appear to be a number of difficulties in this i cchniqllc. The origin of the mplohpoid muscle is ISS easy to tletnch in :he yonng subject with teeth still present 111~~1 in the cdentuhus p~~xon, and. !I, t.11 II1
iil,lCl'
~wrYc~l!s.
titP
Pllt
lllyi(~ily(~i~‘/
P?d$P t?J?dS
to
tK!zC.
~+2iJl,
ligittioJ3
Of
:.CSsels supplying fllc ~lillld clcptndn on thc41* elasticity arid the rlcgiW' lo which they can be dlclivered int,o the wound. If thep arc not adequatrly c’ontrolled, a. considerable hematoma can result. This is untiol&t,c~tIly an opcrat,ion to be performed by those with special experience. 1hc bloid
EXCISION
OF THE SUBMANDIBULAR
SALIVARY
GLAND
The operation for remora1 of the submandibular salivary gland is well known and has been described, for example, by Pat,ey.4 The skin is prepared in the
O.S., O.M. & O.P. May, 1968
usual way, and an incision is mapped out over the submandibular gland. The line of the incision should be in or parallcl to the skin creases and approximately 1.5 cm. below the lower border of the mandible. That is about one third of the way up from the lower pole of the gland to the lower border of the mandible. An incision about 2 inches long is sufficient.. It is helpful to inject a solution containing 1 part Adrenalin in 240,000 parts normal saline into the subcutaneous tissues and beneath the platysma over the arca of operation. If such an injection is made, then the outlining of the incision is particularly useful, as the solution distends the tissues and masks the anatomic landmarks. Provided an Adrenalin solution is injected and the table is tilted, head upward, enough to reduce the pressure in the superficial veins, then an almost bloodless field will be obtained, facilitating a precise dissection. The incision is made down to the platysma (Fig. 19). Pressure with a swab, first on the fat of the upper wound margin and then on that of the lower, will strip the subcutaneous layer off the platysma for a short dista,nce. This maneuver aids closure of the wound in layvers. If a pair of large straight scissors is opened in the sa,me plane at each end of the wound, then the extremities of the wound
Fig.
19
Fig.
20
Fig. 19. The skin incision showing how the subcutaneous tissues can be separated from the surface of the platysma to facilitate the repair of the wound in layers. Fig. $0. The platysma muscle has been incised, exposing the deep fascia which, in this subject, was composed of a single, thick sheet.
are similarly undermined and the incision in the fat can be completed with the same scissors to the full extent of the skin incision. The platysma is divided next and, if an adhesive drape has not been applied, tetra towels are sewed to the wound margins wit,h horizontal mattress sutures (Fig. 20). The investing layer of deep fascia in this part of the neck may be of two types. Tn many persons? particularly women, it is composed of a number of closely applied lamina.e, each of which is quite delicate. In others it is a single, tough, gray-white sheet (Fig. 20). The fascia is best opened by lifting it in the center of the wound with forceps and snipping it with scissors. The scissors can be inserted through the open-
Fig.
i
21
.-“,.Lli
urn, the &eep f&a &as 61% incised and reflected; one part fascia is gripped by the left hand artery forceps, and t,he 1 of I latysma are seen at B. The mandibular branch of the facial -in cW31 ning on its surface, is seen at C; the submandibular saliva1 a n la; If loose connective tissue, is revealed at the anterior end of the wou sh tat l>Ftph node of the submandibular group lying on the ant
O.S., O.M. & O.P. May, 1968
ing and slid laterally to define the individual layers before the opening is extended to the extremities of the wound. The angular tract of fascia is a thickening in the investing layer of deep fascia which spreads downward from the stylomandibular ligament and the angle of the mandible, and it may be encountered as the deep fascia is opened toward the posterior end of the incision. From the deep surface of the investing layer in the region of the angular tract, a sheet of fascia turns medially behind the submandibular gland a,s part of the wall of its fascial compartment. This fascia also passes medially and posteriorly toward the external carotid artery and the internal jugular vein. As the posterior part of the fascial incision is extended, therefore, it is important to separate a layer parallel to the surface, lest the scissors be deflected toward the deeper parts of the neck. The branches of the facial nerve are distributed deep to the platysma. Sometimes they are encountered between the platysma and the deep fascia,, but more often at the level of this incision they are found deep to the deep fascia and loosely applied to its deep surface; hence, the care which should be taken over the division of the deep fascia. Slender branches can be spotted by the tiny blood vessels which run along their length (Fig. 21). The course of the mandibular branch of the facial nerve is variable, and it may pass in a loop quite a distance into the neck.2 Although normally said to recross the lower border of the mandible at the facial vessels, in fact, it can be found below the mandible as far forward as the premolar region. Should a branch of the nerve pass obliquely across the wound, it is best managed by freeing the nerve from the deep surface of the margins of the wound to a point either anterior or posterior to the incision. The nerve can then be held back by means of a retractor applied to one of the wound edges. At this stage, if the edges of the incision are retracted, the anterior facial vein will be seen embedded in the loose connective tissue which surrounds the submandibular gland (Fig. 21). The vein is isolated and divided between ligatures. The upper flap is raised by dividing the connective tissue close to the surface of the gland with scissors, the plane of dissection passing deep to the anterior facial vein. This will ensure that any branches of the facial nerve in the upper flap are raised with the flap, particularly as the mandibular branch of the nerve may pass back above the lower border of the mandible superficial to the vein and at the point where the vein leaves the mandible.3 If the arterial supply to the gland is secured next, the venous engorgement of the gland and the oozing which follow ligation of the anterior facial vein are reduced. To find the facial artery, the lower pole of the gland is dissected up with scissors and then mobilized by finger dissection. A pair of Allis forceps is applied to the posterior border of the lower pole and the gland is turned upward and forward (Fig. 22). The posterior belly of the digastric muscle, with the stylohyoid muscle on its anterior surface, is identified, and a retractor is placed to draw them downward and backward. By separating the loose connective tissue in the interval between the gland and the muscles, the facial artery is exposed. It emerges from behind the stylohyoid muscle and passes upward and forward to
Volume 25 Number 5
Ana,tomic
surgery
for salivary
calczcli
675
Fig I. $4
Fi ig. 63. The gland has been separated from facial artery is exposed where it emerges onto again at this pail 1t. B?ig. 34. The : anterior border of the gland which is she,W?Il at A. The groove between the lvlearl. y seen Inow that it has been separated from facial artery runi 3 forward just above the muscle.
the lower border of the man diblr, and the the outside of the mand ible. It is divided has been freed from the mylc jhyoid muscle, superficial and deep part .s of the gland is the muscle. The submandit branc h of the
enter the deep surface of the gland, and it is frequently accompanied by venae comitantes at this site (Fig. 22). The facial artery may be ligated with the aid of an aneurysmal needle, or it may be clamped kth artcry forceps, divided: and ligated. If the latter course is adopted, it, is advisable to apply t.hree pairs of forceps, dividing the artery ~JdWc1i fhc histal two pairs. Then: if tht: ligatnrc applied below the first of the t~roximal pairs of forceps should break or slip, the artery will he controlled by the second pair. The reason for this cautious treatment of the artery is that mobilization of the gland draws it out from behind the muscles, and as soon as the proximal end is released it retracts out of sight. Thus, should the artery be released before it has been properly liga.ted, the bleeding point could be difficult t.0 find. The course of the facial artery varies between patients. It may emerge from behind t,he stylohyoid muscle at a low level and penetrate deeply into the gland
OS., O.M. & OP. May, 1968 in order to re:tch the upper pole, or it may emerge high up and merelg groove the gland. In the second instance, the artery hardly ascends at all on t,he deep surface of the gland but passes a,lmost horizontally forward before turning downward so as to emerge between the gland and the lower border of the mandible. Low a.rtcries arc easy t,o ligate behind the lower pole of the gland, but high a.rtcrics can be difficult to reach from this aspect. Fortunately, it is the low arteries which are the most likely to be deeply embedded in the gland, since it is under these c,ircumstanccs that the vessel is best dealt with by ligation and division both above and below the gland. High arteries should bc left until the dissection has proceeded sufficiently to allow the gland to be drawn down and the artery to be separated from ibs groove with division of the short glandular branches. The upper flap with the anterior facial vein is retracted and the interval between the lower border of the mandible and the gland is defined. As the lower border of the mandible is approached, a number of venous tributaries will be encountered passing from the gland to the anterior facial vein; also, a number of small glandular vessels from the submandibular artery and vein will be found. Once these have been divided, the gland can be separated from the mandible and the facial artcry will be seen once more, hooking around the mandible to join the anterior facial vein. If the artery has been divided below the gland, then it should be divided again at this point (Fig. 23). The operator should now turn to the anterior border of the superficial part of the gland and transfer the Allis forceps to the ant,erior aspect of the lower pole. Reflecting the anterior border upward and backward exposes the groove in the gland in which the posterior border of the mylohyoid muscle fits (Fig. 24). The muscle is quite firmly and closely applied to the groove in the gland. As the scissors divide the connective tissue which binds the two together, a few small blood vessels which enter the gland from t,he muscle will be divided as well. A finger can now be passed up under the gland so as to lift it from its bed. Finger dissection is augmented where necessary by scissor dissection, with the tips of the scissors kept close against the surface of the gland. By keeping close to the gland, a covering of loose connective tissue is left over the hypoglossal nerve, which lies in a curve diagonally across the underlying hyoglossus muscle (Fig. 26, A and B). It is worth while, as the middle of the medial aspect of the gland is freed, to look out for a vein which is sometimes present (Fig. 26, B). It runs from the gland into the lingual veins which are deep to the hyoglossus. Should the vein be divided before the distal end has been secured, it will retract through the hyoglossus and produce a troublesome hematoma. By using the finger once more as a blunt dissector, the upper part of the posterior border can be freed, whereupon the gland can be drawn downward. Sometimes a particularly tough strand of fascia is attached to the posterior end of the upper pole. If it is present, great care should be exercised in dividing it lest the lingual nerve should be damaged. As the gland is pulled downward, a V-shaped fold of connective tissue comes into view, attached to the upper pole of the gland. It contains both the lingual nerve and the submandibular duct (Fig. 25, A). If they are dissected out with
T’olume 25 Sumher 5
Fig.
65
Fig.
dfi
bringing the s LO& The gland has bringi>. aabbeen mobilided sui?kiently to draw it do&&d, ,W W,U view. YIW. The LW arrow points to the sublingual gang:‘~~u. Right, nq~tts, The .tna lingual n~rvc 10 into ganglion. unner pole wle of the gland and has been displaced disolaced upward unwz en separated from the upper so le the duct of the th’ submandibu1a.r me gland (B), the duet contains two calculi, vvhich I shining through its llru wall. tYyall. The root of the sublingual ganglion is seen Illlz posterior y”uwL’“’ l”“L “L Lilt! auuutL#um,l g”Jqp”u 1: nerve where it crosses the duct, but the ganglion itself is now hidden by the deep gland, which is passing upward anterolateral to, and parallel with, the duct. seen, with the muscles covered by a thin IayFig. %6. Left, The gland bed as it is normally muscle. Right, The counective tissue er 0 f tonne etive tissue: fC) is the tendon of the digastric has been re moved from part of the gland bed so that, a small vein which passed from the deep It is seen clamped by the surf !ace of the gland through the hyoglossus could be controlled. nerve (A) has been uncovered where it passes upward and ah? ‘ry fnrc eps. The hypoglossal tendon (B) divides at this point to embrace the for1 vard *t-l cr the hpoglossus. The stylohyoid digi mtrie.
O.S., O.M. & O.P. May, 1968
care, t,he sublingual ganglion may be seen, applied to the upper pole of the gland, just behind the point at which the duct emerges (Fig. 25, A). Once the nerve has been separated from the gland and the duct, it can be pushed upward quite easily, thus exposing the duct well beyond the point at which the nerve normally passes under the duct to reach the tongue (Fig. 25, B) . Only the duct and the deep part of the gland now attach the gland. A retractor is hooked over the posterior border of the mylohyoid so as to expose the deep part; before the delicate connective tissue which attaches it is divided, however, a pair of artery forceps should be applied just beyond its anterior end. A small artery, which probably originates from the sublingual artery, frequently enters the deep part of the gland at this site. Further traction on the gland will now enable the operator to clamp, divide, and ligate the duct so that only a short stump is left, just enough to drain the major sublingual gland and any posterior sublingual gland which empties into the submandibular duct. The wound is carefully inspected, and any further bleeding points are ligated. A vacuum drain is passed from the gland bed out through the lower flap, and the wound is carefully closed in layers. REFERENCES
1. Downton, D., and Qvist, G.: Intra-Oral Excision of the Submandibular Gland, Proe. Roy. Sot. Med. 53: 543-544, 1960. 2. Faber, M., Van Vooren, P., and Libersa,, C.: Disposition anatomique des branches sousmandrbulaires du nerf facial, Rev. stomato-odont. N. Fr. 16: 143-147, 1961. 3. Last, R. J.: Anatomy-Regional and Applied, ed. 2, London, 1959, J. & A, Churchill, Ltd., p. 491. 4. Patey, D. H.: In Rob, C., and Smith, R. (editors) : Operative Surgery, Vol. 4, Part IV, London, 1957, Butterworth & Co., pp. 149-151.