Repair of Facial Nerve Paralysis After Tumor Surgery



Fig. 11.1
Facial nerve anatomy



Above these are three small branches. The trunk of the facial nerve runs forward from the deep surface of the mastoid process and enters into the gland essence from the deep lobe of the parotid gland; in most cases, it is divided into two branches such as upper and lower branches and then are woven into a single bundle within the parotid gland, which runs between the deep and superficial lobes of the parotid gland and then gives off the following branches radially at the anterior margin of the parotid gland:


  1. 1.


    Temporal branch: It controls the frontal muscle and orbicularis oculi muscle.

     

  2. 2.


    Zygomatic branch: It controls the orbicularis oculi muscle and zygomatic muscle.

     

  3. 3.


    Buccal branch: It controls the cheek muscle, orbicularis oris muscle, and other muscles around the mouth.

     

  4. 4.


    Marginal mandibular branch: It runs downward along the lower margin of the mandible and controls the quadrate muscle and deltoid muscle of the lower lip.

     

  5. 5.


    Cervical branch: It controls the platysma muscle.

     

Since the anatomies of the terminal branches of the facial nerve are highly variable, this brings many difficulties to the surgical exploration of the facial nerve. However, as long as the possible variation is fully considered during surgery, and each patient is regarded as a new variant case, serious and careful operations are performed to safely and quickly expose the facial nerve anatomy and prevent the occurrence of accidental injury of the facial nerve due to surgical operation. The local anatomies of the facial nerve branches and the surgical considerations will be described in detail in the relevant chapters.




1.3 Clinical Classification


The facial paralysis can be classified according to the course of the disease, location, scope, extent, and etiology. According to the etiology alone, it can be classified into congenital, traumatic, neurogenic, infectious, metabolic, neoplastic, toxic, iatrogenic, and spontaneous classes, but given the range of topics in this chapter, only the facial paralyses related to tumor and caused by tumor surgery are discussed herein.

The common tumor-associated facial paralysis includes the following categories:


  1. 1.


    The facial paralysis which is caused by direct tumor invasion of the facial nerve, such as facial nerve neuromas.

     

  2. 2.


    The facial paralysis which is caused by the tumor growth compression on the adjacent facial nerve, such as acoustic neuroma of the brain, the squamous cell carcinoma of the middle ear, meningioma, schwannoma, or other malignant tumors [3, 4].

     

  3. 3.


    The facial paralysis which is caused by removal of the facial nerve and facial muscles during tumor resection, such as facial malignant tumor resection, external ear tumor resection, radical mastoidectomy, acoustic neuroma resection, parotid gland tumor resection, facial hemangioma resection, and neurofibroma resection.

     

  4. 4.


    The facial paralysis which is caused by the injury of the facial nerve, it is commonly seen in the buccal surgery, parotid surgery, and mastoid surgery.

     

However, no matter the facial paralysis is caused by what kind of tumor surgery, what problems faced in the clinical work are actually the repair of injury of the facial nerve and/or facial expression muscle which has occurred, as well as the repair of partial loss or complete loss of facial muscle function.


1.4 Classification of Functional Statuses of Facial Nerves and Muscles


The functional statuses of the facial muscles are directly related to the presentation of facial expressions, and the contraction of the facial muscle is controlled by the facial nerve. Therefore, the treatment of facial paralysis is repair of functions of facial nerves and muscles. The functional statuses of facial nerves and muscles are classified to directly reflect the functional statuses of the facial nerves and muscles. Therefore, the classification is performed according to the anatomy of the expression muscle (Fig. 11.2), anatomy of the facial nerve (see Fig. 11.1), and their functional statuses, which has significant clinical implications for guiding the treatment and repair of facial paralysis. Summarizing the experiences in repair of facial paralysis in the clinic, the authors have proposed the following classification:

A435194_1_En_11_Fig2_HTML.jpg


Fig. 11.2
The anatomies of the facial expression muscle


1.4.1 Classification of Facial Nerve Functional Statuses





  1. 1.


    Complete transection of the facial nerve: It is the complete injury of the facial nerve which is caused by the surgery or trauma.

     

  2. 2.


    Incomplete transection of the facial nerve: It is the partial injury of the facial nerve which is caused by the surgery or trauma.

     

  3. 3.


    Complete degeneration of the facial nerve: It is injury and degeneration of the facial nerve after resection of the intracranial tumors (the acoustic neuroma is more common).

     

  4. 4.


    Absence of the facial nerve: It is congenital and trauma-induced complete or partial facial nerve defect.

     

  5. 5.


    The getting lost of the nerve axons: After the nerve is broken, the surgical suture causes the dislocation anastomosis of the nerve bundle branch or the regenerated nerve axons get lost. Due to the dislocation growth of the neural axons, the error will occur in the transmission of action potentials, which causes the corresponding facial muscle movement disorders or the occurrence of the synkinetic movement, false movement of different facial muscles, and abnormal facial expressions.

     


1.4.2 Classification of Functional Statuses of the Facial Muscles





  1. 1.


    Absence of facial muscles: Congenital complete absence or partial absence of facial muscles and partial absence of facial muscles caused by surgery and trauma. The facial muscles after denervation gradually degenerate and thus result in fibrosis and loss of contractile function.

     

  2. 2.


    Complete paralysis of facial muscles: At the early stage of the facial nerve injury, the facial muscles have no muscle strength, but the facial muscles are not yet completely denatured. After regeneration of the nerve, the paralyzed facial muscles can be innervated again to restore contractile function.

     

  3. 3.


    Partial paralysis of facial muscles: Parts of the facial muscles are denervated.

     

  4. 4.


    Insufficient muscle strength of facial muscles: Part of facial muscles has muscle strength, and the muscle strength of bilateral facial muscles is out of balance, which causes the asymmetric facial expressions.

     

  5. 5.


    Facial muscle spasm: The facial muscles show involuntary spasm-like contraction.

     

  6. 6.


    Synkinetic movement and false movement of facial muscles: The facial muscles can contract, but the movements are out of control; there is no coordinated movement or there is only platelike synkinetic movement and false movement. The synkinetic movement of the affected orbicularis oculi muscle, zygomatic muscle, and risorius muscle is most commonly seen; when the patient closes his eyes, the contractions of the affected zygomatic muscle and risorius muscle will be triggered, which makes the mouth skewed to the affected side; and when the patient smiles, the affected corner of the mouth cannot contract, which makes the mouth skewed to the healthy side.

     

  7. 7.


    Abnormal attachment points of the facial muscles: In congenital or trauma-induced abnormal attachment points of the facial muscles, because the attachment points on bilateral facial muscles are asymmetric, which leads to distortion of commissure and grotesque expression.

     

It can be seen from the clinical classification of facial paralysis that the facial muscles and facial nerves in various parts are likely to be injured, respectively, and different combinations of injuries will exhibit a variety of forms of facial paralysis. Therefore, it is required to understand the medical history as detailed as possible and perform scrupulous physical examinations before treatment, including the determination of the cause, onset time, injured location, and assessment of injured degree, and then the appropriate method is selected according to the rehabilitation requirements and physical conditions of the patient, characteristics of the original disease, recurrence rate, and the prognosis of the disease.


1.5 Treatment Protocols


There are various surgical methods for the repair of facial paralysis, but they are basically divided into two types, namely, static and dynamic repairs. The static repair can only maintain bilateral symmetry of the face at the static state; once the facial activities appear, for example, when the patient talks, smiles, and shows expression on the corner of the mouth, the facial deformity will still occur. Therefore, currently, the static repair is only used as supplementary means for dynamic repair in clinics and is not used alone. The dynamic repair can also be divided into two types such as physiological dynamic repair and nonphysiological dynamic repair [5, 6].


1.5.1 Physiological Dynamic Repair





  1. 1.


    The broken ends of the injured facial nerve are sutured directly, or the broken ends are sutured after nerve transplantation. The original innervation of the facial nerve may be restored at the affected side, and the original facial muscle function may be recovered. The method is suitable for patients in the early stages with good proximal and distal ends of the facial nerve.

     

  2. 2.


    The cross-face nerve transplantation: According to the principle that most facial movements are bilateral synchronous movements, the nervous impulses at the healthy side are transferred to the affected side through nerve transplantation to control the affected facial muscles to move synchronously with that at the healthy side. Such repair method is only suitable for patients with early facial paralysis, that is, no atrophy or degeneration has been detected in facial nerve branches and facial muscles.

     

  3. 3.


    Replacement of the paralyzed facial muscle through transplantation of the muscle flap carrying blood vessels and nerves to the affected side. The control nerve of the muscle flap crossing the face is anastomosed with the branches of the facial nerve at the healthy side, and the facial nerves at the healthy side are used to control the contraction of the transplanted muscle. Consequently, the corner of the mouth is pulled, and the affected side can move synchronously with the healthy side to restore a symmetrical smile and thus achieve the purpose of being similar to the normal physiological activities of the facial expressions. The surgical method is suitable for patients with late facial paralysis, that is, atrophy or degeneration has been detected in facial nerve branches and the facial muscles [7–10].

     

  4. 4.


    The existing surgical method still cannot obtain a natural and casual smile for the reasons below:


    1. (1)


      There are as many as ten facial muscles controlling the fine activities of the corner of the mouth at one side, and thus it is not possible to recover all delicate facial expressions only through transplanting a muscle.

       

    2. (2)


      In the facial muscles, the ratio of the nerve axons to the muscle fibers dominated by them is 1:25, and the ratio of the nerve axons to the transplanted bone and muscle is 1:200 to 1:150. The fewer muscle fibers each muscle fiber controls, the more sophisticated the controlled activity is; therefore, the delicate expressions exhibited by the facial expression muscles cannot be manifested by the contraction of the skeletal muscles. Nonetheless, it is still possible to recover a particular facial expression (e.g., smile) through single muscle transplantation to meet the need of the patient for social activities.

       

    3. (3)


      If the nerve at the healthy side is used to control the muscle activity at the affected side, it is necessary to carry out the nerve transplantation. Since the transplanted nerve during surgery is longer and the passing rate of nerve regeneration is low (only 20–50% of axons pass through), the effect of the transplanted nerve would be difficult to predict. At present, the regulatory mechanism of nerve regeneration has not been fully deciphered. It is not guaranteed that the nerve regeneration can be achieved and the harvested nerve can control the transplanted muscle accurately, so the surgical effect is still unstable.

       

    4. (4)


      The existing surgical method has high technical requirements, and it needs to be completed together by two to three groups of surgeons with skilled microscopically techniques. Thus, although the physiological dynamic repair is the direction of the repair of facial paralysis, due to great surgical trauma, slow postoperative recovery, uncertain effect, and high technical requirements, the drawbacks such as the synkinetic movement and false movement of facial muscles may occur. The doubts of the surgeons and patients on the surgical effect affect the popularization and application.

       

     


1.5.2 Nonphysiological Dynamic Repair





  1. 1.


    Local muscle flap transposition: The facial muscle flap at the affected side is translocated and is sutured and fixed with the corner of the mouth at the same side. When the muscle flap contracts, the corner of the mouth is pulled to restore smiling facial expression at the affected side. At present, the temporal muscle and masseter muscle are mostly taken as the dynamic muscles. After this kind of prosthetics is completed, the contraction of the dynamic muscle is not synchronized with the facial muscle activity at the healthy side, and thus it must be practiced to coordinate with the healthy side. The nonphysiological dynamic repair takes the temporal muscle and masseter muscle as the dynamic muscles. Because its muscle flap is transferred with pedicle and the nerve regeneration process is avoided, the postoperative recovery is quick and the effect is stable. But the patient should go through certain practicing for this kind of smile, and that this kind of smile can only be made when gritting one’s teeth and mastication, while this will make the patient’s smile looks like grinding his or her teeth. When the patient eats and chews, there will be involuntary strange spasm in the corner of the mouth, and this is difficult to be accepted by the patient. Therefore, it is now rarely used. Nevertheless, the nonphysiological dynamic repair has characteristics such as quick recovery, stable effect, easy operation, and low risk; thus, there is an urgent need to further improve the existing surgical method in the clinic.

     

  2. 2.


    Transposition of sternocleidomastoid: In 1999, the author designed the use of the sternocleidomastoid as a power source to repair the late facial paralysis, avoiding the disadvantage of the original surgical method, which has achieved a very good clinical effect.

     


1.5.3 Personalized Repair Methods


Since there are numerous and diverse surgical methods for repair of facial paralysis, how to select the appropriate surgical methods for repair of various facial paralyses is the primary issue every clinician must address. According to the classification of the functional statuses of facial muscles and facial nerves, the appropriate individualized repair surgery programs can be designed based on the damage situation. Based on years of clinical experience, the authors summarize the designing scheme for repair of facial paralysis to provide some reference for the performers, in order to obtain good repair effect.


  1. 1.


    The repair method for the facial paralysis due to facial nerve trunk injury:


    1. (1)


      The main reasons of facial nerve trunk injury: The most common facial nerve trunk injury occurs mostly within the range from the facial canal within the petrous portion of the temporal bone to the portion of the parotid gland, and it is caused mostly by tumor resection or accidentally injured due to surgical operation. Once the facial nerve trunk injury is observed, the immediate completion of connection between nerve stumps is the simplest method among all repair surgeries, and it can also be expected to get the best recovery effect. The direct apposition suture cannot be performed often due to scar formation and contracture in the nerve stumps during the delayed nerve stump surgery, and it is often required to carry out nerve transplantation in the space between nerve stamps. The cross sections for the nerve to pass by are increased (about 30% of regenerated nerve axon bundles will be reduced for each additional cross section passed through by the nerve). As a result, the number of regenerated nerve axon bundles that are allowed to pass is reduced, which directly affects the surgical effect.

       

    2. (2)


      Common surgical methods and their effects:


      1. 1)


        Apposition suture of nerves: It is suitable for patients with neurotmesis and intact proximal and distal nerve ends. The effect is most ideal due to direct apposition suture of nerves.

         

      2. 2)


        Nerve transplantation: The nerve transplantation can be performed for patients with defects in neural stumps. Due to increase of cross sections for the nerve to pass by, the effect is greatly affected.

         

      3. 3)


        Cross-face nerve transplantation: If the proximal nerve is damaged, and the distal nerve and the facial muscle are intact, the nervous impulses of the proximal end of the branch of the facial nerve at the healthy side are transmitted to the distal end of the branch of the facial nerve at the affected side to restore the muscular tension and expression activities of the affected facial muscles through cross-face nerve transplantation. For the success of cross-face nerve transplantation, the transplantation should be carried out in the early stage of the facial paralysis. To confirm that the distal end of the nerve and the facial muscles at the affected side are intact, the transplanting cultivation of the nerves is performed before the regenerated nerve axons reach to ensure that the facial muscles will not shrink. In this way, the regenerated nerves can be connected with the motor end plates. The hypoglossal nerve can be transposed to the facial nerve for parasitic culture; after the cross-face transplanted nerves grow long enough, the distal facial nerve will be separated with the hypoglossal nerve. Since the regenerated axons of the nerve need to pass through two cross sections, and the nerve regeneration still needs to pass through a distance of more than 15 cm, the recovery time is longer, which will take about more than 1 year. Once the operation is successful, the affected facial muscles can move synchronously with the facial muscles at the healthy side, but the effect is not ideal in most cases.

         

      4. 4)


        Neuronal replacement with accessory nerve and hypoglossal nerve transpositions: The proximal end of the hypoglossal nerve or accessory nerve is used to replace the facial nerve and is connected with the distal end of the facial nerve, which is also suitable for the patients with intact distal facial nerve. The surgical method has been widely used for these reasons: the operation is easy and the nerve regeneration passes through only one cross section, and therefore it takes about 4–6 months to restore the activities of the affected side; the disadvantage is that due to damage to the donor site of the hypoglossal nerve or accessory nerve, most of the facial movements at the affected side are the plate-shaped synkinetic movements; in the early postoperative period, when the patient shrugs (accessory nerve transposition) or moves the tongue when chewing (hypoglossal nerve transposition), the affected face will be distorted. The ultimate effect will be determined by the result of long-term training of the patient.

         

       

    3. (3)


      Case I: The patient, female, had facial paralysis after parotid gland tumor resection and underwent the facial nerve repair surgery (Fig. 11.3).

      A435194_1_En_11_Fig3_HTML.jpg


      Fig. 11.3
      Case I. (a) The facial nerve trunk and branches were separated off after parotid gland tumor resection. (b) Before facial nerve repair for left facial paralysis. (c) The left facial paralysis had been repaired 4 months after facial nerve repair

       

     

  2. 2.


    Repair method for facial paralysis due to facial nerve branch injury:


    1. (1)


      The common causes of facial nerve branch injury: In clinical practice, the facial nerve branches are wrapped within the tumor body mostly due to the growth of the parotid gland tumor and cheek tumor; the facial nerve branches can only be removed together when the tumor resection is performed. In addition, if the tumor body is too close to the facial nerve within the surgical field, there are more bleedings in the surgical field, and the surgical field is unclear; all these factors can also easily lead to accidental injury of the facial nerve branches.

       

    2. (2)


      Common surgical methods and their effects:


      1. 1)


        Neural anastomosis: The immediate direct apposition suture of the broken ends of the nerve branch is the repair method with best effect.

         

      2. 2)


        Nerve transplantation: When the space between the broken ends of the nerve branch is too large to perform direct suture, the free autologous nerve transplantation can be performed. The great auricular nerve, the cutaneous branch of the cervical plexus, the cutaneous branch of the radial nerve, and the sural nerve are selectively used as the donors for nerve transplantation. Compared with the direct neural anastomosis, the effect is a bit poor.

         

      3. 3)


        Cross-face nerve transplantation: The nervous impulses at the healthy side are transmitted to the affected side through nerve transplantation to restore the synchronous movements of bilateral facial muscles; of course, the affected facial muscles must be intact, if the facial muscles have been injured, and it is needed to select other surgical method.

         

       

     

  3. 3.


    The repair method for the facial paralysis due to the facial muscle injury:


    1. (1)


      Common causes of facial muscle injury: Mostly due to the tumor growth, the facial muscles will be wrapped within the tumor body; when the tumor resection is performed, the facial muscles can only be removed at the same time. In addition, the denervated facial muscles are degenerated into the fibrous tissue and lose their contractile functions in the later period of injury in the proximal end or the branch of the facial nerve.

       

    2. (2)


      Common surgical methods and their effects:


      1. 1)


        Free muscle transplantation during neurovascular anastomosis: It belongs to the physiological dynamic repairs. The donors of muscles for the first-stage transplantation with relatively positive effects include the latissimus dorsi muscle, gracilis muscle, and rectus femoris muscle, of which, it is more commonly seen that the latissimus dorsi muscle is transplanted to repair the facial paralysis. The surgical method has the advantages that the nerve has only one anastomotic stoma, and the facial recovery is quicker compared to the second-stage muscle transplantation; the disadvantages are that the surgical trauma is big, and the requirements for surgical techniques are demanding; when the nerve localization result is inaccurate, the transplanted muscles may produce false movements. If the nerve branches of the transplanted muscle are dissected mistakenly or the blood vessels are improperly sutured during the operation, the surgical failure will easily occur [11].

         

      2. 2)


        Pedicled sternocleidomastoid muscle transposition: It belongs to the nonphysiological dynamic repair. The pedicled sternocleidomastoid muscle at the affected side is transposed to the corner of the mouth at the affected side, and the movements of the corner of the mouth at the affected side are reconstructed. The surgical method has the advantages of positive effect and less trauma and quicker recovery; the disadvantages are that there is a cervical incision scar after surgery, and the smiling face can be recovered only after simple training [12, 13].

         

      3. 3)


        Pedicled temporalis muscle transposition: It belongs to the nonphysiological dynamic repair. The temporal muscle attachment points at the affected side are stripped off from the temporoparietal area, and this muscle is turned over downward together with the aponeurosis and periosteum at the top and then passes through the subcutaneous tunnel to be sutured with the corner of the mouth, and the activities of the corner of the mouth are mobilized when the temporal muscles contract. The advantages include positive effect and rapid recovery; the disadvantages are that the temporal depression is obvious, and the smile can only be presented when the patient grinds his or her teeth to mobilize the activities of the corner of the mouth, and the smile is less natural.

         

      4. 4)


        Direct suture of facial muscles: For the patients with ruptured facial muscles, the direct suture of facial muscles can receive good results. Especially the ruptured facial muscles at the medial side of the connecting line from the outer canthus to the corner of the mouth may be accompanied by ruptured facial nerve branch. The local nerve branch has been very small, and its exposure is quite difficult, while the suture of the muscle is conducive to the regeneration of nerve branches in the near side of the broken ends of the muscle, and thereby the denervated distal muscle can be innervated to restore the function of the facial muscles.

         

       

     

  4. 4.


    The repair method for facial paralysis with facial soft tissue defects: The facial soft tissue defects mostly refer to skin defects in the parotid area. The facial soft tissue defects are more commonly seen in patients with hemangioma, neurofibroma, and malignant tumor in the face and cheek which have invaded the skins; at the same time, for tumor resection, the skin tissues which have been invaded must be resected. The local skin defect may be repaired with local skin flap transfer, pedicled local myocutaneous flap, or free myocutaneous flap with vascular anastomosis. Commonly used surgical methods are as follows:


    1. (1)


      Cervical local skin flap transfer: It is suitable for patients only with skin defects in the parotid area but without defects in the facial muscles and the facial nerve. The retroauricular and cervical skin flap is harvested by surgery and is rotated forward to cover the wound; if the cervical donor site cannot be sutured directly, it can be repaired with transplantation of skin grafts.

       

    2. (2)


      Transplantation of free latissimus dorsi myocutaneous flap: It is suitable for patients who have facial paralysis and larger buccal skin defects after tumor resection:


      1. 1)


        Surgical design and skin flap harvesting: A skin flap slightly larger than the size and shape of cheek skin defect is harvested, and the latissimus dorsi myocutaneous flap attached under the flap is harvested according to repair needs, and then it is sutured and fixed between the temporal fascia and corner of the mouth for repair of the facial paralysis. The thoracodorsal artery and vein of the skin flap can be anastomosed with the facial artery and vein, and the control nerve can be anastomosed with the ipsilateral facial nerve to restore some activities of the affected face.

         

      2. 2)


        The repairing principle and surgical method for the huge facial defect after tumor resection: For patients with huge facial soft tissue defects, the repair of facial paralysis is not the key point, while the latissimus dorsi myocutaneous flap can be used to cover the wound. The huge facial tumors often involve the frontoparietal area to the ipsilateral mandible, and the wound left after debridement can reach up to 25 cm × 15 cm. For such a huge wound, the primary problem is to use the tissue with good blood supply to cover the wound. Because there are exposures of bones and cavities in the wound, the vascularized free myocutaneous flap transplantation is the only option. At present, the myocutaneous flaps in the human body available for selection only include the latissimus dorsi myocutaneous flap. The latissimus dorsi myocutaneous flap has large area, rich blood supply, strong resistance to infection, easy operation, and hidden position, and thus it is most commonly used in the clinic. It is not necessary to consider the repair of the facial paralysis during surgery, and it is feasible to mainly perform the simple covering. Because the myocutaneous flap has a considerable thickness, it is required to properly enlarge the sections around the area covered by the skin flap when the area of the skin flap is designed. The blood vessels of the donor site can use the facial artery and vein and can also use the superior thyroid artery and the lateral superficial cervical vein. The thoracodorsal nerve can be anastomosed with the facial nerve. Since the latissimus dorsi myocutaneous flap is too thick and heavy, the postoperative skin flap is prone to sagging deformation, which requires multiple repair and construction to improve the appearance as far as possible.

         

      3. 3)


        Case II: The patient, female, had left facial hemangioma, and the wound had been festering. The left facial defects occurred after extensive resection of the tumor. The latissimus dorsi myocutaneous flap was used to repair the left face, and the wound healed well after surgery (Fig. 11.4). However, because the latissimus dorsi myocutaneous flap is too hypertrophic and heavy, the skin flap is prone to sagging deformation after surgery, which requires multiple repair and construction to improve the appearance.

        A435194_1_En_11_Fig4_HTML.jpg


        Fig. 11.4
        Case II. (a) Preoperative appearance of left facial hemangioma. (b) Left facial tissue defect after tumor resection. (c) After repair of left facial defect with latissimus dorsi myocutaneous flap

         

       

    3. (3)


      The first-stage repair with pedicled sternocleidomastoid muscle flap: It is suitable for patients with defects in the facial nerve trunk, and it branches after tumor resection which cannot be repaired with nerve transplantation:


      1. 1)


        Surgical design: According to the need to repair the facial paralysis, the sternocleidomastoid muscle flap of appropriate length is prepared and was rotated to the face, and the ends of the muscle flap are fixed to the sites such as the orbicularis oculi muscle and orbicularis oris muscle, respectively, to correct facial paralysis. The innervation depends on the isolated sternocleidomastoid muscle branch of the accessory nerve, or the remaining facial nerve trunk is anastomosed with the sternocleidomastoid muscle branch of the accessory nerve. When the facial skin defects exist, the pedicled sternocleidomastoid muscle flap is used for the first-stage repair of the facial paralysis and facial skin defects.

         

      2. 2)


        Case III: The patient, female, had recurrence after resection of parotid carcinoma with right facial paralysis. It was observed during surgery that the facial nerve was invaded and destructed, the tumor was extensively resected, the sternocleidomastoid muscle flap with an appropriate length was prepared according to the repair need and was rotated to the face, and the ends of the muscle flap were fixed to the sites such as the orbicularis oculi muscle and orbicularis oris muscle, respectively. The remaining facial nerve trunk was anastomosed with the sternocleidomastoid muscle branch of the accessory nerve. After completion of radical surgery of parotid carcinoma, the sternocleidomastoid muscle flap with the sternocleidomastoid muscle branch of the accessory nerve was used for the first-stage repair of the facial paralysis (Fig. 11.5).

        A435194_1_En_11_Fig5_HTML.jpg


        Fig. 11.5
        Case III. (a) Preoperative appearance. (b) Surgical incision design. (c) The invaded and destructed facial nerve observed in the operation. (d) Result of radical surgery of parotid carcinoma. (e) The sternocleidomastoid muscle flap with the sternocleidomastoid muscle branch of the accessory nerve was used for the first-stage repair of the facial paralysis. (f) After surgery

         

       

    4. (4)


      Transfer of pedicled sternocleidomastoid muscle flap: It is suitable for patients with facial paralysis and smaller cheek skin defect after tumor resection:


      1. 1)


        Surgical design: An appropriate skin flap is designed and harvested according to the size and shape of cheek skin defect and the length of the muscle belly of the sternocleidomastoid muscle, so as to prevent that due to a too close distance of the skin flap from the mastoid process, the radius of the muscle flap after rotation is too small, so that the skin flap cannot cover the cheek wound.

         

      2. 2)


        Case IV: The patient, female, had right cheek tissue defects after tumor resection. The sternocleidomastoid myocutaneous flap was designed and harvested, and the sternocleidomastoid myocutaneous flap was used to repair the tissue defects, and the wound healed well after surgery (Fig. 11.6).

        A435194_1_En_11_Fig6_HTML.jpg


        Fig. 11.6
        Case IV. (a) Postoperative frontal view. (b) Postoperative lateral view. (c) Design of the sternocleidomastoid myocutaneous flap. (d) After repair with the sternocleidomastoid myocutaneous flap

         

       

     



2 Commonly Used Methods of Surgical Repair of Facial Nerve Paralysis


The repair of facial paralysis is a very challenging problem for plastic surgeons. In order to repair the complex disease, it is very necessary to be familiar with all kinds of surgeries which can improve the functions and repair the appearances. Through careful examination, comprehensive analysis, serious consideration, and carefully formulated repairing plan, each patient can undergo individualized repair, in order to achieve the desired restoration of the function and appearance [14].


2.1 Anastomosis and Repair of the Facial Nerves



2.1.1 Indications


The anastomosis and repair of the facial nerves are suitable for patients with the early facial nerve injury and rupture. The broken ends of the facial nerve after rupture should be sutured as soon as possible, but the patients often delay the best repairing time due to various circumstances and the fluke mind. The surgical suture is generally performed within 6–12 months after injury, which is still likely to get better results.


2.1.2 Surgical Methods





  1. 1.


    Facial nerve exposure: Since the anatomic variation of the facial nerves is greater, especially the various branches of the facial nerve constantly give off subbranches and then are fused into each other, it is difficult to find the cases with identical anatomies in the clinic. According to many years of clinical experiences of the authors, if the facial nerve needs to be exposed during surgery, it is recommended to perform the surgery with the following basic methods:


    1. (1)


      Exposure of the first-grade branch of the facial nerve: The first-grade branch of the facial nerve (trunk) penetrates out from the stylomastoid foramen at the deep surface in front of the mastoid process, runs forward and downward at the superficial surface of the posterior belly of digastric muscle, and enters into the deep surface of the parotid gland at the deep surface of the sternocleidomastoid muscle. In order to facilitate the exposure, some attachment points of the sternocleidomastoid muscle are stripped off from the mastoid process, and a 1.5 cm bone at the lower anterior end of the mastoid process is carefully resected, and then it can be exposed in its deep surface.

       

    2. (2)


      Exposure of the second-grade branches of the facial nerve: The second-grade branches of the facial nerve (temporal trunk and cervical trunk) present as a plexiform shape and pass through the parotid gland between the deep and superficial lobes of the parotid gland.

       

    3. (3)


      Exposure of the third-grade branches of the facial nerve: The third-grade branches of the facial nerve (temporal branch, zygomatic branch, buccal branch, mandibular marginal branch, and cervical branch) penetrate out slightly radially from the anterior margin of the parotid gland.

       

    4. (4)


      Exposure of the fourth-grade branch of the facial nerve: Of the fourth-grade branches of the facial nerve (terminal branches), in addition to that the branch controlling the cheek muscle enters into the muscle from the superficial surface, most branches enter into the muscle belly from the deep surface of facial expression muscles under their control. When the surgical exposure is performed, the proximal end of the facial nerve may be sought out among the normal tissues, and then the search is performed carefully toward the distal end.

       

     

  2. 2.


    Suture of the broken ends: The broken ends of the nerve can be exposed according to the anatomical layers of different positions of the facial nerves. After the defects in the broken ends of the nerve or the generated neuroma are removed, as long as there is no large section of defect between the broken ends of the nerve, and the suture tension is not too large, most broken ends of the nerves can be closed and sutured directly. When the suture is performed, it is recommended that the orientations of the neural axons should be correctly aligned under the surgical microscope and thus avoiding the twisting and malposed suture of the broken ends of the nerve. A 9-0 minimally invasive monofilament suture needle thread is used; when the suture is performed, only the nerve sheath should be sutured. If the diameter of the nerve is larger, it can be sutured through passing through the membrane between nerve axons to assure the accurate apposition suture. The facial nerve trunk can be sutured with four to six stitches, and the branch can be sutured with two to four stitches, and the thinner peripheral branch can be sutured with only one stitch. The main points of the operation include the thorough local hemostasis, the accurate apposition of the broken ends of the nerve, no excessive suture tension, and soft and delicate operation.

     

  3. 3.


    Postoperative treatment: The local drainage is performed to prevent hematocele and effusion, and the antibiotics are used to prevent infection. It is recommended that the neurotrophic drugs are used for more than 3 months.

     

  4. 4.


    Precautions: The facial nerve of the child is thinner, so the exposure of the nerve is very difficult. Once it is damaged, the difficulty of repair is doubled. In addition, the mastoid process in children has not yet been fully developed, thus the positioning during exposure of the facial nerve trunk is slightly different with that of the adult. Because the facial nerve is not covered by the mastoid process, it is easily damaged, which should be paid full attention during surgery.

     

The patients in whom the facial nerve is accidentally cut off during parotid gland tumor resection should undergo immediate neural anastomosis. Because the parotid gland has been removed, the broken ends of the nerve can be anastomosed without tension, and so the good recovery can often be obtained. If the suture cannot be performed immediately during surgery, the repair should be carried out as soon as possible within 2 weeks. If the repair is delayed too long, the local scar adhesion is obvious, which can lead to difficulty in nerve exposure, not only increasing the surgical difficulty, but also affecting the effect of repair. The nerve regeneration is rather slow; the postoperative effect to children is significantly better than that to adults, while the elderly have a weak regenerative capacity, and so the surgical effect is relatively poor. Therefore, the patients should be informed of the effect of related nerve surgery before surgery.


2.1.3 Typical Case



Case V

The patient, female, had facial paralysis due to facial nerve rupture after left parotid gland tumor resection. Because the parotid gland had been removed, the broken ends of the nerve could be anastomosed without tension, and the good recovery could often be obtained. At 6 months after surgery, the left paralyzed facial nerve was repaired, and the recovery condition was good (Fig. 11.7).

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Fig. 11.7
Case V. (a) Postoperative frontal view. (b) Intraoperative exploration of the facial nerve situation. (c) At the sixth month after facial nerve repair for the patient with left facial paralysis


2.2 The Repair with Facial Nerve Transplantation



2.2.1 Indications


The facial nerve is damaged and ruptured in the early stage, and the proximal and distal ends of the facial nerve are intact. But when a large segment of nerve defect between the broken ends cannot be closed and sutured directly, the repair with facial nerve transplantation can be performed. The repair of facial nerve defect after parotid gland tumor resection is the most commonly seen repair in the clinic.


2.2.2 Surgical Methods


The selection of the donor nerve should be determined according to the nerve length required for transplantation. The great auricular nerve can be used when the length of the transplanted nerve is less than 10 cm. It is suggested that the sural nerve is used when the length of the transplanted nerve is more than 10 cm:


  1. 1.


    The harvesting of the great auricular nerve: The great auricular nerve penetrates out from the Erb’s point at the mid-upper one third of the posterior margin of the sternocleidomastoid muscle and then runs toward the direction of the external auditory canal and parotid grand, which can be used as the marker for confirmation (Fig. 11.8).The local hypesthesia in the periauricular area may occur after the harvesting of the great auricular nerve.
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Mar 19, 2018 | Posted by in Reconstructive surgery | Comments Off on Repair of Facial Nerve Paralysis After Tumor Surgery

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