Surgical Atlas of pediatric otolaryngology - part 3 pps

Facial Nerve Exploration and Repair 159 • If placement of a sural nerve graft is anticipated, the lower leg, ankle, and foot are similarly prepared. A surgical glove is placed over the toes, and the foot and leg are draped with a sterile stockinette and placed on a sterile sheet. An extremity drape is used to cover the leg. • A thyroid or a split sheet is used to cover the patient and to drape the entire surgical field. • The scrub nurse stands next to the surgeon and in front of the back scrub table. Surgical loupes and the microscope should be available to help the surgeon locate and dissect along the nerve. Procedure Figure 7–18 overviews extratemporal exploration and repair for lesions. Figure 7–18 Extratemporal exploration and repair for parotid and nonparotid lesions. 160 Surgical Atlas of Pediatric Otolaryngology No 1. Incision and exposure • The proposed preauricular incision (Figure 7–19) is marked with a surgical marker. ♦ In older children and adolescents, the incision will be less noticeable if curved posteriorly to conform to the anatomic indentation just superior to the tragus, inferior to the tragus, or both. The incision continues just inferior to the earlobe and posteriorly onto the mas- toid process and is then curved inferiorly and anteriorly about 2 cm inferior to the mandible rim, preferably within a skin crease (see Figure 7–19 A). Alternatively, the postauricular portion of the incision can be continued into the hairline or directly posteriorly into the hair as in a facelift incision. ♦ In infants (in whom the mastoid tip has not yet developed) and in patients in whom the course of the nerve is considered anomalous, an upper neck incision is made 2 cm inferior to the rim of the mandible and curving onto the postauricular area. After the skin incision is made, the skin flap is elevated superiorly with sharp and blunt dissection until the facial nerve is located. The incision can then be extended superiorly, if necessary (see Figure 7–19 B). 4 Figure 7–19 A, Incision line for parotidectomy. Incision may be extended ( arrows) as necessary to the neck, hairline, or into the hair. B, Incision line for parotidectomy in infant with undeveloped mastoid tip. After the facial nerve is identified, the incision can be extended along the dotted line as necessary. (Reproduced and adapted [ A only], with permission from Farrior JB, Santini H. Facial nerve identification in children. Otolaryngol Head Neck Surg 1985;93:174–6.) A B Facial Nerve Exploration and Repair 161 • The skin flap is elevated using sharp and blunt dissection to a point about 1 cm superior, anterior, inferior, and posterior to the parotid gland. Elevation usually is continued until the zygomatic arch, the buccal fat pad, the upper one-third of the neck, and the mastoid tip are exposed (Figure 7–20). • The anterior border of the sternocleidomastoid muscle is identified. The great auricular nerve is located at the posterior border of the upper midportion of the sternocleidomastoid muscle and is exposed superiorly until it branches just inferior to the auricle. The nerve is kept in position as long as possible. In smaller infants, transecting the great auricular nerve may be unnecessary because the parotid gland is more anterior than it is in older children and adults. 4 Figure 7–20 Elevation of parotidectomy skin flaps to expose zygoma, buccal fat pad, masseter muscle, and sternocleidomastoid muscle. 162 Surgical Atlas of Pediatric Otolaryngology • The anterior border of the sternocleidomastoid muscle is dissected medially until the posterior belly of the digastric muscle is located (Figure 7–21). The inferior border of the parotid gland is retracted superiorly, and the digastric muscle is followed to its origin, medial to the mastoid tip (the digastric muscle originates at the level of and inferior to the stylomastoid foramen, through which the facial nerve exits). This dissection in infants may suffice to locate the main trunk of the facial nerve, because the parotid gland in infants is more ante- rior (Figure 7–22). 4 • The preauricular area is dissected medially along the external canal perichondrium. The parotid gland is retracted anteriorly. Sharp and blunt dissection is continued medially until the cartilaginous “point- er” is identified at the bony cartilaginous junction of the external auditory canal (Figure 7–23). • This dissection plane is continued superiorly to the level of the zygo- matic arch. The preauricular dissection is continued medially, both superior and inferior to the expected location of the facial nerve. This technique facilitates eventual visualization of the nerve by widening the surgical field. Figure 7–21 Retraction of inferior parotid gland and stern- ocleidomastoid muscle to locate posterior belly of digastric muscle. 164 Surgical Atlas of Pediatric Otolaryngology No 2. Identifying the facial nerve • The facial nerve is located about 1 cm medial to the tympanomastoid suture line and the cartilaginous pointer at the external auditory canal–bony cartilaginous junction, just anterior to the stylomastoid foramen (Figure 7–24). ♦ This area is separated with blunt dissection parallel to the expect- ed course of the nerve. ♦ Bleeding is controlled with clamps, 3-0 absorbable suture ties, bipolar cautery, a Shaw scalpel, or light pressure using small or large moist dissecting sponges. Figure 7–24 Exposure of main trunk of facial nerve and its tem- porofacial and cervicofacial divi- sions. Facial Nerve Exploration and Repair 165 • Proper surgical technique is essential when working near the facial nerve: ♦ The surgeon should minimize any contact with the facial nerve and its branches. ♦ Visualization obscured by blood can be improved by lightly touch- ing the facial nerve with small and large moist dissecting sponges. Minimal pressure should be applied, and the nerve should not be rubbed or suctioned. ♦ In most cases, knowledge of the anatomy of the facial nerve should obviate the need for a facial nerve stimulator, which can further traumatize the nerve. ♦ In revision surgery, post-traumatic exploration, and certain patients with extensive neoplastic disease and infection, however, the nerve may be identified through judicious use of a facial nerve stimulator at its lowest setting. • If the main trunk cannot be identified or if it is incorporated in scar tissue or tumor, peripheral branches must be located and dissected in retrograde fashion to the main trunk in the following areas: the mandibular branch, temporal branch, buccal branches, and zygomat- ic branch. • The mandibular branch, or ramus mandibulae, is located in the neck lateral to the facial vessels and just superior to the submandibular gland. ♦ In many infants this branch is located more superiorly, lateral to the mandible. ♦ In older children, if the mandibular branch is not located easily, the fascia of the submandibular gland can be incised and elevated superiorly along the posterior facial vein until the cervical or mandibular branch is identified. • The temporal branch is usually found overlying or just superior to the zygomatic arch deep to the superficial fascia, about halfway between the anterior border of the auricle and the lateral bony orbital rim. • A buccal branch can be found coursing near and parallel to the parotid duct about 1 to 1.5 cm inferior to the zygomatic arch. • The zygomatic branch can often be identified between the anterosu- perior border of the parotid gland and the lateral inferior orbital rim. • Rarely, for large neoplasms or when severe scarring has resulted from prior surgery or trauma, mastoidectomy is indicated. In that circum- stance the facial nerve is explored to locate the nerve and follow it through the stylomastoid foramen. • Once the main trunk has been identified, blunt dissection is contin- ued anteriorly along the trunk until its bifurcation is located; the facial nerve is then identified conclusively, and the parotid tissue lat- eral to the nerve can be incised with a Shaw scalpel or with a No 11, 12, or 15 blade. 166 Surgical Atlas of Pediatric Otolaryngology • Dissection along the nerve can be facilitated initially with a fine hemostat such as a McCabe facial nerve dissector. Once the proper plane has been established, curved mosquito-type forceps and small Kelly clamps suffice. Each branch is dissected to a point distal to the parotid gland (Figure 7–25). No 3. Superficial and deep parotidectomy • If possible, the parotid gland between the branches is removed with the pathologic specimen. As large a margin of normal parotid tissue as is possible is included around any tumor or cyst. • If, after the superficial portion of the parotidectomy has been com- pleted, the disease process is medial to the facial nerve, the nerve is elevated gently with sharp and blunt dissection. The main trunk and each of the cervicofacial branches are retracted with vascular loops to expose the underlying parotid tissue (Figure 7–26). • The masseter muscle is identified anteriorly and medially to expose and remove the tissue medial to the facial nerve. Dissection is begun in a plane lateral to the masseter fascia and is continued to the poste- rior border of the masseter muscle at the ascending ramus of the mandible. • A second dissection plane is begun on the mastoid tip inferior to the stylomastoid foramen and the main trunk of the facial nerve. This plane is continued medially and is connected with a plane beginning on the bony canal superior to the facial nerve trunk. • The remaining parotid tissue, which may be in the parapharyngeal space, can be removed by advancing along the dissection planes. ♦ If necessary to protect the facial nerve, this portion of the excision can be done in segments from between the branches of the nerve or superior or inferior to the main trunk and to the superior or inferior branches of the nerve. ♦ When dissecting superior to the trunk and posterior to the frontal branch, care should be taken to avoid injuring the auriculotempo- ral branch of the third division of the trigeminal nerve. This branch lies near the superficial temporal artery between the auricle and the mandible. • In patients with large tumors of the parapharyngeal space, anterior traction on the mandible may provide adequate additional operating space. Otherwise, mandibular osteotomy and mandibular swing may be necessary to adequately visualize and access the site so as to suffi- ciently facilitate removal of tumor or parotid tissue. 168 Surgical Atlas of Pediatric Otolaryngology • Once the pathology specimen has been removed, the nerve is inspect- ed to ensure that it is intact: ♦ If transected at the trunk or at the temporalis, zygomatic, or mandibular branches, the nerve is reapproximated using the fewest 9-0 or 10-0 monofilament nylon sutures needed to achieve coap- tation (Figure 7–27). ♦ Anastomosis of severed buccal branches is usually unnecessary because of the rich interanastomosis of buccal branch nerve fibers. ♦ The cervical branch is routinely sacrificed during parotidectomy, and it does not require repair because loss of function is minimal. • If a segment of the nerve has been removed, an immediate interposi- tion nerve graft can be sutured in place (Figure 7–28). ♦ If delay of grafting is elected, the severed proximal and distal ends should be marked with nonabsorbable (nylon) sutures to facilitate localization at subsequent repair. ♦ Instead of using an interposition graft, less important branches may be severed and anastomosed to more valuable branches—for example, the buccal to the temporal or zygomatic branch, or the buccal or cervical to the mandibular branch (Figure 7–29). 18 Figure 7–27 Sutured laceration of main trunk of facial nerve. 170 Surgical Atlas of Pediatric Otolaryngology • The wound is irrigated with saline solution, and the facial nerve is re- examined for continuity. • A Penrose or vacuum drain is placed inferior to the trunk, posterior to the branches, and through either the inferior neck incision or a separate incision. • The preauricular skin can be approximated with 3-0 to 4-0 catgut and 4-0 to 5-0 nylon sutures. The neck incision can be approximat- ed with staples. • Antibiotic ointment is applied to the incision. Fluffed gauze sponges and 10 cm × 10 cm dressing gauze sponges are used for a pressure dress- ing. A Barton or nylon tubular net dressing can be applied for pressure. Postoperative Care • Facial function is checked when the patient is awakened from anesthesia. ♦ If paresis or paralysis is present and the nerve was left intact, the patient is observed. ♦ If paralysis is present immediately after surgery and was not present preoperatively, and if the status of the nerve was not checked, the nerve should be explored to establish continuity, and any lacerations should be repaired. • The patient is observed for hematoma, seroma, salivary fistula, corneal irritation, or new facial paralysis. Gustatory sweating may be a late com- plication. • Artificial tears are used, and if the eye is affected by facial paresis or paralysis, the eyelid is closed before sleep. • The dressing is re-inforced overnight to absorb bloody drainage. The drain is removed on the first or second postoperative day or when drainage is minimal or nonexistent. • The pressure dressing is applied for 4 to 7 days, and the sutures or sta- ples are removed on the seventh postoperative day. • If the nerve was intact at the end of surgery, any postoperative paresis should resolve in 4 to 6 weeks. If paralysis is present, recovery should begin within 3 months and should continue for 12 months. [...]... sponges and elastic tape ♦ • • • • Figure 7 33 The sural nerve, located adjacent to the saphenous vein in the lower part of leg 180 Surgical Atlas of Pediatric Otolaryngology • An appropriate number of 9-0 or 1 0-0 monofilament nylon sutures is used to approximate the perineurium of the graft to the epineurium of the nerve (Figure 7 35 ) Depending on the width of the proximal and distal nerve stump or... appropriate number of 9-0 or 1 0-0 monofilament nylon sutures (Figure 7 36 ) • Sacrifice of the hypoglossal nerve results in paralysis of the ipsilateral side of the tongue and ipsilateral facial contraction during deglutition Facial function can be relearned • The wound is irrigated with sterile saline, and the skin incision is approximated with 3- 0 or 4-0 chromic catgut sutures and with 4-0 or 5-0 nylon sutures... The Medical Editing Department of Kaiser Foundation Research Institute provided editorial assistance 184 Surgical Atlas of Pediatric Otolaryngology REFERENCES 1 Proctor B The anatomy of the facial nerve Otolaryngol Clin North Am 1991;24:479–504 2 Clemente CD, editor Gray’s anatomy of the human body 30 th ed Philadelphia: Lea & Febiger; 1985 3 Hollinshead WH Anatomy for surgeons 3rd ed I The head and... floor of the canal in the tympanomastoid sulcus area and is removed from the remaining anterior attachment (Reproduced with permission from Johnson JT, editor American Academy of Otolaryngology- Instruction Courses Vol 4 St Louis (MO): CV Mosby; 1991.) B, Space created from its removal (arrow) enables enlargement of the inferior portion of the cartilaginous canal 200 Surgical Atlas of Pediatric Otolaryngology. .. cavity is smaller (Figure 8–29B) Figure 8–29 The size of the diameter of the meatal opening affects the size of the mastoid recess A, A small diameter B, A large diameter (Reproduced with permission from Johnson JT, editor American Academy of Otolaryngology- Instruction Courses Vol 4 St Louis (MO): CV Mosby; 1991.) A B 206 Surgical Atlas of Pediatric Otolaryngology No 5 Canal wall–up procedure • The mastoid... Figure 7 31 A, Avulsed parotid tissue and facial nerve B, Superficial and underlying parotid tissue is removed to enable approximation of nerve branch ends after avulsion n = nerve; m = muscle (Adapted and reproduced with permission from Tucker HM The management of facial paralysis due to extracranial injuries Laryngoscope 1978;88 :34 8–54.) 174 Surgical Atlas of Pediatric Otolaryngology • In cases of delayed... the bony-cartilaginous junction 188 Surgical Atlas of Pediatric Otolaryngology Procedure The described approach is applicable to a wide variety of otologic procedures, including tympanoplasty, mastoidectomy (wall–up or wall–down), and repair of ear canal stenosis (acquired or congenital) The ear canal surgical methods described include endaural and postauricular approaches (Figures 8–2 and 8 3) Table... the spread of the solution being confined to the tightly adherent skin overlying the tympanic bone 190 Surgical Atlas of Pediatric Otolaryngology • Through an ear speculum, using a stapes knife, a horizontal incision is made in the ear canal 2 -3 mm lateral and parallel to the annulus (Figure 8–4) The incision extends from above the lateral process of the malleus (12 o’clock) to the floor of the external... (Reproduced with permission from Johnson JT, editor American Academy of Otolaryngology- Instruction Courses Vol 4 St Louis (MO): CV Mosby; 1991.) 194 Surgical Atlas of Pediatric Otolaryngology No 2 Postauricular approach • The skin is incised just posterior to the skin crease using an electrosurgical unit with a needlepoint tip (Figure 8– 13) The dissection separating the tissues that connect the auricle... fascicles of the sural nerve also can be grafted (see below) Use of the great auricular nerve as a graft leaves a cutaneous sensory deficit over the mastoid process and auricle No 2 Sural nerve graft • The sural nerve is formed by the junction of the communicating ramus of the lateral sural cutaneous nerve and the medial sural cutaneous nerve in the middle of the leg 178 Surgical Atlas of Pediatric Otolaryngology . tape. Figure 7 33 The sural nerve, located adjacent to the saphenous vein in the lower part of leg. 180 Surgical Atlas of Pediatric Otolaryngology • An appropriate number of 9-0 or 1 0-0 monofilament. by the junction of the communicating ramus of the lateral sural cutaneous nerve and the medial sural cuta- neous nerve in the middle of the leg. 178 Surgical Atlas of Pediatric Otolaryngology ♦ The. Tucker HM. The management of facial paralysis due to extracranial injuries. Laryngoscope 1978;88 :34 8–54.) 174 Surgical Atlas of Pediatric Otolaryngology • In cases of delayed repair, the nerve