MINISTRY OF EDUCATION AND TRAINING MINISTRY OF DEFENCE 108 INSTITUTE OF CLINICAL MEDICAL AND PHARMACEUTICAL SCIENCES --- BUI MAI ANH ANATOMICAL RESEARCH AND CLINICAL APPLICATIONS OF
Trang 1MINISTRY OF EDUCATION AND TRAINING MINISTRY OF DEFENCE
108 INSTITUTE OF CLINICAL MEDICAL AND
PHARMACEUTICAL SCIENCES
-
BUI MAI ANH
ANATOMICAL RESEARCH AND CLINICAL
APPLICATIONS OF MASSETER NERVE IN INTERMEDIATE
DURATION FACIAL PARALYSIS TREATMENT
Speciality: Odonto-Stomatology
Code: 62720601
ABSTRACT OF MEDICAL PHD THESIS
Hanoi – 2019
Trang 2Thesis is completed at:
108 INSTITUTE OF CLINICAL MEDICAL AND
The thesis can be found at:
1 National Library of Vietnam
2 Library of 108 Institute of Clinical Medical and Pharmaceutical Sciences
Trang 3INTRODUCTION
The injury of the nerve VII due to various causes makes paralysis of facial muscles The functions of facial muscles play an important role in communication The injury of the nerve VII also causes some functional effects such as eye protection function There are many studies offering different methods of surgey to reduce facial deformity, but each method of surgery is effective only on each patient and donor nerve that was intervened
by surgery
Facial nerve injury at an early stage of less than 2 years has the ability
to be restored by direct surgical intervention However, the use of adjacent nerves only resolves the problem of active facial vibrations and is not identical
to the healthy half-face
Facial nerve graft has been studied by many authors for a long time However, this method is still limited Masseteric nerve surgery is used to replace the old method with positive results
In Vietnam, surgery for facial paralysis treatment has been carried out for a long time However, there has not been any study on surgery and applications
of masseteric nerve in a systematic way, so we conduct research on the topic
”Anatomical research and clinical applications of masseter nerve in intermediate duration facial paralysis treatment” for the following purposes:
1 Course of masseteric nerve anatomy
2 Evaluate results of the applications of masseteric nerve in surgical treatment of intermediate durationfacial paralysis
Trang 4Chapter 1 OVERVIEW
- Location: According to Kun Hwang, MN is located at 33 ± 5.6 mm
from the lower limit of masseter muscleon the longitudinal line 1/3 before the masseter muscle and 47 ± 5.5 mm from the lower limit on the vertical line 1/3 after
- Microscopic anatomy: Through microscopic anatomical results, it can be seen that the number of MN axons is much larger than other nerves, which is one of the good conditions for recovering nerve transmission when it
is used as a source
1.2 Surgical methods to restore facial muscles by the time of paralysis 1.2.1 Acute facial paralysis (paralysis time <3 weeks)
- Purpose: release pressure for the nerve VII or nervous joint, transplantation
to restore function of facial muscles
- Methods:
+ Direct neuronal joint: apply to all cases of the nerve broken for injury, surgery with condition of 2 nerve endings after the excision with organization defect under 1cm
+ One-sidedness facial nerve segmentation graft: apply when injured nerve deficiency is 1cm or more
Trang 51.2.2 Intermediate durationfacial paralysis (from 3 weeks to 2 years)
- Methods: Surgery for one-sidedness facial nerve graftor nervous graft
through the circuit
- Facial nerve transition: The nerve often used is: nerve XII, masseteric nerve
Transfer of nerves XII-VII: usually joined at the end - on the side and joined
to the main body of the nerve VII Transfer of masseteric nerve – branch of the nerve VII mouth on the side of the paralysis: usually linked to the end of microsurgery of the MN branch and the nerve VII mouth branche
1.2.3 Chronic facial paralysis(> 2 years)
- Methods:
+ Local muscle transfer surgery: the muscle often used is a temporal muscle with the condition that the trigeminal nerve is not injured
+ Micro-surgical transfer surgery: in cases where the transfer of local muscles
is difficult or has not the desired results, the free muscle transfer is a good choice Free muscles are commonly used: slim muscles, large back muscles, small chest muscles, and muscles in form of big toe
1.3 Situation of applications of masseteric nerve in facial paralysis treatment
1.3.1 Masseteric nerve transfer in intermediate durationfacial paralysis treatment (<2 years)
Intermediate durationfacial paralysishas the ability to restore the nerve VII transmission to recover the movement of the muscles clinging to face skin,
it is very positive because at this time the muscles clinging to face skin is not degenerated, not atrophied
With studies using nervous sources to recover the nerve VII transmission from MN, many reports show very positive results even up to 24
Trang 64month paralysis
The authors suppose that due to distance of MN to the nerve VII branches is quite close and the number of axons of MN is two to three times higher than the number of axons of the wire VII branches, so the ability to recover is higher than other nerves
The synergy issue is also mentioned by the authors, but the reports show that this is not too big issue for patients nor affect surgical results
1.3.2 Using MN source in chronicfacial paralysis (> 2 years)
Like the direct transfer of MN, the use of MN for muscle transplantation has many advantages such as ease of surgery, short recovery time, the used nerve does not affect the function
However, the authors also said that the use has disadvantages such as when lifting the edge, it is necessary to bite with the bitting and the time to create a natural smile must be 2-4 years after surgery To overcome this problem, some authors have used dual nervous joint with two places: MN and facial nerves with the movement nerves of the grafted muscle to create spontaneous and natural laughs In 2012, Biglioli reported a series of free muscle grafts, with two nervous sources (MN, facial nerves) and very positive results
In the future, functional magnetic resonance imaging may be used to study this process in facial paralysis and to explore the cortex areas that are activated while smiling with the patients who use MN as source of free muscle transplantation To achieve in spontaneous way, symmetrical smiles, an important part is due to post-operative recovery of smile function when standing in front of the mirror with exercises and biofeedback
1.3.3 In Viet Nam
Trang 7In Vietnam, peripheral neuropathy joint techniques are also performed
by many surgeons in orthopedic, neurosurgical and jaw surgery From the 1990s, N.B Hung (1998), N.H.Phan (1999) used micro vascular-neuro-microsurgical techniques to more accurately suture and join, Dr Son (2000) reported on the technique of suturing and covering the bundle of fibers in the nervous joint and transplant The use of facial nerves in the nerve VII recovery has also been reported by author N.T.Son since 2003, with positive results and one of the options in the facial paralysis treatment Studies on anatomy and
MN applications have also been reported, but there have been no further studies on anatomy and application on Vietnamese people
Trang 8Chapter 2 RESEARCH SUBJECTS AND METHODS
2.1 Research subjects
- Research on fresh cadaver: 22 specimens /11 fresh cadaver (including 6 men
and 5 women) from 35-73 years old, 9 fresh cadaver were studied in Ho Chi Minh City University of Medicine and Pharmacy, 02 fresh cadaver at Viet Duc Hospital, unknown age (unidentified cadaver)
- Clinical research: Patients with facial paralysisdue to various causes
in the period from 3 weeks to 24 months had surgery to transfer one-sidedness
MN at the Department of Maxillofacial Surgery-Plastic Surgery-Aesthetics,
Viet Duc Hospital from 11 / 2009-12 / 2017
2.1.1 Selection criteria and exclusion of patients
- Criteria for selection on cadaver: The specimens on the fresh cadaver are intact in the face area, have not been surgically or previously injured Exclude specimens that are not properly preserved, face areas are injured
- Criteria for patients selection: Patients with facial paralysisaccording
to FNGS 2.0 classification from grade 4 to grade 6 for not more than 24 months paralysis; The patients were diagnosed with intermediate durationfacial paralysis; For facial paralysis patients with unidentified paralysis causes (Bell paralysis), the time for surgery indication is more than 6 months if there is no sign of clinical recovery; There are no systemic diseases that endanger the surgery; had surgical treatment in plastic surgery and maxillofacial surgery; Follow up patients after periodic treatment of 1 month,
3 months until the end of the studies
2.2 RESEARCH METHODS
Trang 92.2.1 Research design:
- Research on fresh cadaver: Observation and description research
- Clinical research: Retrospective, prospective, clinical intervention, controlled
non-2.2.2 Research facilities and equipment
- Research on fresh cadaver:
+ Use surgical instruments, measurer, loupe
+ Carry out the surgery on each side of fresh corpse, with supine position of the head tilted to the opposite side
+ Skin incision along Blair incision line from the temple through the tragus to the jaw corner about 1/3 of the length of mandibularbone
+ Operate of the facial muscle layer, operate to the front bank, the bank on the salivary glands
+ From the anterior border of the parotid glands, operate to find branches of the nerve VII: the mouth branch, the cheek branch Then retrograde surgery into the parotid salivary glands
+ Remove the shallow lobe of glands that preserve nerve VII branches
+ Reveal the whole nerve VII
+ Continue to remove the deep lobe to expose the entire masseter muscle below
+ Measure the index of masseter muscle as below
+ Continue operating the layers of masseter muscle, peeling according to the layers
+ Find donor nerve and masseter muscle arteries in the deep layer of masseter muscle
+ Measure indicators
Trang 10- Clinical research:
+ Clinical examination of the patients: assessing injury status of the nerve VII according to House and Brackmann score (FNGS 2.0); measure commissure excursion amplitude; assessment of facial nerve injury; masseteric muscle function; classify causes of injury; body situation
+ Subclinical assessment: MRI, CT to search for causes of the nerve VII injury; EMG to determine vulnerability; do tests to exclude other diseases + Perform the surgery
2.2.3 Improved content in surgery to find MN
Through clinical and anatomical researches on the fresh cadaver, we map out the "MN zone” as follows:
+ Upper limit: zygomatic branch
+ Lower limit: buccal branch
+ Posterior limit: the parallel line and measure the distance from the tragus to the branching position of MN
+ Anterior limit: the line parallel to the posterior limit and about 1cm from the posterior limit
MN zone is limited when connected 04 lines above and in the deep layer of masseter muscle
2.2.4 Follow uppost operation
- The patient was monitored at the hospital during 5-07 days
- Follow up immediately after surgery about hematoma, bleeding, infection
- Periodic observation: 03 months, 06 months, 12 months to assess the time of axon regeneration by manifesting the movement of facial muscles clinically
- Evaluation of the time onset of vibration based on the patient perception when biting, it will result in muscle vibrations of the mouth in paralysis side
Trang 11- Evaluate the time when the patients can laugh spontaneously without bitting
- Evaluate postoperative masseter muscle function: measuring the maximum distance of the mouth opening, the patient's ability to chew
- Evaluate by observation, grading according to FNGS 2.0, measure commissure excursion calculated from the middle of the upper lip Compare before and after surgery by taking pictures, filming, electromyography
2.2.5 Rehabilitation post operation
- Immediately during the first week after surgery, the patient is instructed to eat by chewing on the surgery side to increase neurotransmitter ability
- The first month after surgery, the patient does not massage the surgical side Gentle massage will be performed after surgery from the second month
- The patient will practice regular chewing on the surgical side until the first signs of muscle self-perceived by the patient for 3-6 months
- After the first signs of muscle vibration, the patient will have to practice in front of the mirror: clenching the teeth with a smirk, and making symestry smile at least 02-03 times / day Every 15-20 minutes
- Rehabilitation with the mirror will help patients to separate movements by adjusting the bitting force Therefore, it limits the synkinesis
- Patients will always understand that biting will motivate and equilibrate mouth corners, which will help create a pathway from the adaptor cortical and patients can have a natural, spontaneous smile after the practice from 24-72 months
Trang 122.3 Data processing
- Analysis on software STATA 12.0
- Research classification is as follows:
Type 1: Very good
- FNGS 2.0: Grade I, Grade II
- Electromechanics: There are signs of the movement unit of the facial muscle (optional conditions)
- Spontaneaous smile
- Difference in amplitude from the healthy side is <3 mm
Type 2: Good
- FNGS 2.0: Grade I, Grade II
- Electromechanics: There are signs of the movement unit of the facial muscle(optional conditions)
- Movement needs bit with bitting
- Difference in amplitude from the healthy side is <5 mm
Type 3: Fairly
- FNGS 2.0: Grade III
- Electromechanics: There are signs of the movement unit of the facial muscle(optional conditions)
- Movement needs bit with bitting
- Difference in amplitude from the healthy side is ≥5 mm
Type 4: Average
- FNGS 2.0: Grade IV
- Movement needs bit with bitting
- Difference in amplitude from the healthy side is >5 mm
- Electromechanics: There are signs of the movement unit of the facial
Trang 1311muscle(optional conditions)
Type 5: Poor
- FNGS 2.0: Grade V, VI
- Movement needs bit with bitting
- Difference in amplitude of the mouth movement calculeted from the upper lip middle is small or quite zero
- Electromechanics: There is no electric potential difference when biting
2.4 Ethics in research
- Objectives and methods should be considered carefully so that the benefit of patients is priority 1
- Patients voluntarily participate in research
- Information security and use for research purposes