Đặc điểm lâm sàng, chẩn đoán hình ảnh và kết quả phẫu thuật tạo hình cung sau sử dụng nẹp vít điều trị bệnh hẹp ống sống cổ do thoái hóa tt tiếng anh

QUESTION
Cervical spinal stenosis due to degeneration is a common spinal pathology in middle-aged people.
Cervical spine stenosis can present many clinical symptoms with different levels: from cervical spine pain,
shoulder pain or radiculopathy. The treatment cervical stenosis restores cervical spine function, relieves pain,
restore movement, brings patients back to normal life.
In surgical treatment, for one or two levels cervical stenosis, the authors often have used anterior
procedures. Japanese authors have used laminoplasty to expand the cervical spine canal in order to limit the
disadvantages of laminectomy.
In Vietnam, the treatment of multilevels cervical stenosis by laminoplasty has also achieved much
more improvement. Since 2009, at 108 Military Central Hospital, we have used titanium mini-plates in
maxillofacial surgery to do laminoplasty. Until now, through medical literature reference in our country, we
found that, there has not been a domestic research project that has fully and detailed research on diagnosis,
surgical treatment as well as the result of laminoplasty with titanium mini-plate. Therefore, we carried out the
project "Clinical characteristics, image diagnosis and operative results of open door laminoplasty using
maxillo-facial mini plate to treatment cervical stenosis due to degeneration" with two objectives:
1. Describe clinical features and images of cervical stenosis in patients with multilevels stenosis due to
degeneration, had laminoplasty indication.
2. Evaluation of surgical results, some factors related to surgical results and applicability of
laminopasty surgery procedure.
New contributions of the thesis:
1.

Describe the clinical characteristics and images of patients group with multi-levels cervical stenosis
due to degeneration who had cervical laminoplasty indication.

2.

The dynamic magnetic resonance imaging method of cervical spine allows an accurate assessment spinal
cord compression condition in 3 positions. However, it has not been mentioned in domestic medicine
literature. This is a new finding of the thesis. It helps clinicians having a comprehensive view and
diagnostic orientation for patients who do not have suitalbe between clinical signs and and magnetic

resonance images.

3.

Laminoplasty brings many benefits: range of motion preserved, good neurological recovery, safety, less
complications.

4.

Laminoplasty using maxillofacial tinanium mini-plate save treatment costs while ensuring safety and
treatment effectiveness.

The layout of the thesis:

The content of the thesis is presented in 110 pages, including 4 chapters. Question: 02 pages; Chapter
1 – Overview document: 37 pages; Chapter 2 – Patients and research methods: 18 pages; Chapter 3 - Research
results: 23 pages; Chapter 4 - Discussion: 28 pages; Conclusion: 2 pages. The thesis includes: 36 tables, 43
figures. Reference: 150 documents.


Chapter 1
OVERVIEW DOCUMENT
1.1 History of laminoplasty research in the treatment myelopathy due to cervical stenosis
1.1.1 In the world
In 1968, Kirita et al used air drill to do cervical laminectomy, showed a significant improvement in the
clinical situation as well as a reduction complications rate compared to using kerrison.
Many laminoplasty techniques were developed based on the using air drill machines such as the Z
laminoplasty of Oyama and Hattori (1973). Hirabayashi's technique was expansive open door laminoplasty of
unilateral hinge type (1977). In 1980, Kurokawa et al developed double-door laminoplasty technique (spinous
process splitting laminoplasty).

Since then, the laminoplasty of cervical spine falls into two categories according to the design of the
osteotomy: the unilateral hing-type method such as Hirabayashi's and bilateral hinge-type method such as
Kurokawa’s.
1.1.2 The situation of cervical laminoplasty researches in Viet Nam.
In Vietnam, the cervical myelopathypathy has been diagnosed and treated in the 90s of the 20 century.
Diagnosis of cervical stenosis with cervical myelography and then by magnetic resonance imaging. Since 1995,
at the Department of Spinal A, Ho Chi Minh City Orthopedic Trauma Center, Vo Van Thanh et al have begun to
treat cervical stenosis by surgery. Nguyen Trong Yen and Pham Hoa Binh (2009) reported the initial results of
cervical stenosis surgery by laminoplasty using maxill-facial titanium mini-plate for satisfactory results.
Phan Quang Son (2015) published the topic of treatment of cervical stenosis by laminoplasty
combined with using coral graft, recovery rate was 58.5 ± 12.8%, good and excellent results was 81.2%.
The researches on surgical treatment of the medullary pathology due to the above mentioned stenosis
stenosis mainly intervene in the front, only a few studies interfering with the posterior way by the method of
creating the back bow as the author Vo Van Thanh, Phan Quang Son, ... These studies use the method of creating
the rear arc with hinge on either side or hinged on one side fixed the back bow with steel thread while the
method of creating the rear arc is hinged on one side. The modification with the use of facial jaw titanium braces
only had one report by Nguyen Trong Yen and Pham Hoa Binh with 7 patients, as well as no long-term followup studies on the treatment results of this method. Our research was designed to answer these requirements.

Chapter 2
SUBJECTS AND METHODS OF RESEARCH


2.1 Research subjects
Consisting of 31 patients with diagnosis of multilevel cervical stenosis due to degeneration had
operatived by cervical laminoplasty using titanium miniplate and screws at 108 Central Military Hospital from
February 2011 to October 2015.
2.1.1 Standard selection of patients
- Clinical examination of patients with cervical myelopathy.
- Imaging diagnosis: There was no cervical kyphosis (lordosis angle > 0 0), no ossification of posterior
longitudnal ligament. On the magnetic resonance imaging: Multilevels spinal cord compression ( 3 levels or

more) due to degeneration (hypertrophy of the ligaments, swelling of the disc, bone mine, loss of cerebrospinal
fluid around the spinal cord ...)
- Surgical treatment by post-arterioplasty using facial jaw screw splint.
- Followed and treated after surgery according to the uniform process.
2.1.2 Exclusion criteria
- Patients with cervical stenosis due to degeneration was operatived by cervical laminoplasty using maxillofacial plate combined with another surgery on the cervical spine.
- Patients with cervical stenosis due to degeneration had other previous surgeries on the vertebrae.
- Patients did not agree to participate in the study, or patients with cervical stenosis due to degeneration were
treated laminoplasty but inadequate monitoring, not enough research data.
2.2 Research methods
2.2.1 Research design
Describe the series of cases, prospective, no control.
2.2.2 Sample selection and sample size
Sample size is calculated according to the formula:
*p*(1-p)]/d2

N=[

Z: numerical value from normal distribution, with error type 1 = 0.05, Z(1-/2) = 1,96
p: expected value of ratio = 0.92.
d: accuracy = 0.1.
Calculated: N = 28.3.
2.2.3 Research content
2.2.3.1 Clinical research
- Clinical symptoms of multistage spinal stenosis due to degeneration were noted
2.2.3.2 Research on image diagnosis
- Image characteristics on X-ray film, computerized tomography and magnetic resonance imaging were recorded
and analyzed.
2.2.3.3 Research on surgical treatment
- Anesthesia: endotracheal anesthesia

- Patients position: prone with a cervical spine bent or in an intermediate position.
- Surgical tools:
+ Set of specialized tools for spinal surgery.
+ Titanium mini palte and screws of Biomet Microfixation Company


+ Surgical microscope.
+ High speed drilling machine.
+ X-ray machine (C-arm) during surgery.
- Surgical technique:
Step 1: Expose spinal processes, laminla and lateral masses.
Step 2: Create hinges and open doors along both sides of the laminas.
Step 3: Spinal cord decompression.
Step 4: Put the plate and screw to fix laminas at the door opening position.
Step 5: Close the incision.
- Evaluation in surgery:
+ Which is the hinge side.
+ Number of laminas were laminoplasty did.
+ Time amount of surgery.
+ Blood transfusion during surgery.
- Accidents and complications:
+ Accident in surgery: tearing of the dural sac, spinal cord and nerve roots injury, fracture of lamina.
+ Postoperative complications: incision infection, cerebrospinal fluid leakage, meningitis, epidural
hemorrhage, paralysis C5 after surgery, cevical kyphosis post operation.
2.2.3.4 Evaluation of surgical results
- Evaluation time:
+ The close results were assessed when the patient was discharged.
+ The far results were recorded after surgery 12 months.
- Evaluation of clinical results:
+ The rate of recovery Hirabayashi.

Recovery rate (%) = (post-op JOA score – pre-op JOA score)
(17 – pre-op JOA score)

x 100

+ Split into 4 groups:


Excellent (recovery rate ≥ 75%)



Good (50 ≤ recovery rate <75%)



Fair (25 ≤ recovery rate <50%)



Poor (recovery rate from <25%).

- Evaluate treatment results according to the study image:
+ Routine X-ray: Measure the lordosis angle of the cevical spine, range of motion, thereby calculating
the preservation range of motion of cervical spine.
+ Computerized Tomography Scanner: Measure the diameter of cevical cannal after operative, the
image of bone healing on the hinge side.

2.2.3.5 Identify relationships

Assessment of factors related to treatment outcomes: Age, gender, duration of disease, patient's condition
before surgery, Torg –pavlov index pre-operative, diameter of spinal canal pre-operative, number of laminas
which were done laminoplasty.
2.2.4. Data collection and analysis.
Data analysis was done by medical statistical methods using SPSS 20.0 software. Using t-test pairing
algorithm and Pearson correlation coefficient test to find the relationship between variables, p <0.05 is
considered statistically significant.

Chapter 3


RESEARCH RESULTS
3.1 Age and gender
3.1.1 Gender
In 31 patients, there were 21 males (67.7%) and 10 females (32.3%). The ratio of male/female is
approximately 2/1.
3.1.2 Age
The average age of the study group was 56.84 ± 8.23 years (the youngest was 38 and the oldest was 73).
3.2 Clinical characteristics
3.2.4 Clinical symptoms
Table 3.4. Clinical symptoms at admission
Clinical symptoms

Number of pts

Ratio (%)

Cervical pain only

16

51,6

Cervical pain, arm pain

4

12,9

Upper extremity

1

3,2

Lower extremity

4

12,9

A half of body

2

6,5

Extremities

23

74,2

Belong nerver roots

7

22,6

Regional

22

71

A half of body

1

3,2

Under the spinal cord lesion

8

25,8

Sphincteric dysfuntion

21

67,7

Hoffman’s sign: Positive

26

83,9

Babinski’s sign positive

10

32,3

Lhermitte’s sign positive

4

12,9

Autonomic Nervous Dysfunction

2

6,5

Cervical pain
Movement disorder

Sensory disorder

- Symptoms of myelopathy and radiculopathy
Table 3.5. Symptoms of myelopathy and radiculopathy
Symptoms

Number of pts

Percentage (%)

Myelopathy

26

83,9

Myelo-radiculopathy

5

16,1

Total
31
100
- The average pre-operative JOA score was 7.65 ± 2.48 (the lowest was 3 points, the highest was 13 points).

3.3 Imaging diagnosis

3.3.1 Imaging on routine X-ray
Table 3.9. Measure lordosis angle and range of motion of cervical spine on dynamic X-ray
Kind of angle

Average value

Min

Max

Lordosis angle

22,35 ± 9,03

1

35

Flexion angle

14,61 ± 9,15

0

33

Extension angle

31,16 ± 9,20

15

45

Rang of motion angle

45,26 ± 10,25

24

63

3.3.2 Magnetic resonance imaging
Table 3.11. Number of cervical stenosis level on magnetic resonance imaging
Number of stenosis level

Number of pts

Percentage (%)

Three levels

9

29

Four levels

10

32,3

Five levels

12

38,7

Total

31

100

3.3.2.2 Morphology lesions on magnetic resonce imaging
Table 3.12. Morphology lesions on magnetic resonce imaging.
Morphology lesions

Number of pts

Ratio (%)

Bulging disc

31

100

Yellow ligament hypertrophy

29

93,5

Hypertensive on T2W

30

96,8

Hyportensive on T1W

4

12,9

3.3.3 Computer Tomography Scanner Imaging
Table 3.14. Antero-posterior cervical canal diameter on CT scanner
Veterbrae (n=23)

Anterior-posterior diameter (mm)

C3

10,52 ± 1,13

C4

9,78 ± 1,40

C5

9,57 ± 2,05

C6

9,95 ± 1,56

C7

11,63 ± 1,48

3.4 Operative


3.4.1 Postion and number of laminoplasty laminas
Table 3.16. Postion and number of laminoplasty laminas
Number of

Postion

pts

Number of laminoplasty laminas

Rate (%)

C3C4C5

2

6

6,5

C4C5C6

6

18

19,4

C5C6C7

1

3

3,2

C3C4C5C6

7

28

22,6

C4C5C6C7

3

12

9,7

C3C4C5C6C7

12

60

38,7

Total

31

127

100%

3.4.4 Complications and death
The rate of epidural tear met in 1 patient (3.2%). No cases of C5 paralysis, cerebrospinal fluid leakage
and local infection, nor death.
3.5 Evaluation of surgical results
3.5.1 Close results
- The JOA score was estimated to be 12.10 ± 1.92 on discharge from the hospital.

- Recovery rate was 44.45 ± 23.15%.
Table 3.17. Compare the JOA score between pre-operative and discharge
Time of follow up

JOA score

Pre-op

7,65 ± 2,48

Discharge

12,10 ± 1,92
p < 0,01

3.5.2 Far results
The average postoperative follow up time was 37.68 ± 15.85 months (the shortest is 12 months and
the longest is 70 months).
- JOA scores average 14.42 ± 1.97 points. Recovery rate is 69.43 ± 26.22%. Excellent and good
results accounted for 83.9% while the poor rate was 6.5%.

- Imaging diagnosis:


Table 3.22. Angles of cervical movements
Value (0)

Angle
Lordosis angle

14,15 ± 9,69

Flexion angle

12,70 ± 8,43

Extension angle

26,19 ± 10,79

Rang of motion

36,44 ± 13,71

+ Percentage of preservation range of motion of cervical spine: 84,37 ± 3,34%. (n=27)
+ Percentage of bone dealing on the computerized tomography scanner on the hinge was 100%
(n=26).

Chapter 4


DISCUSSION
4.2 Clinical characteristics
4.2.4 Clinical symptoms
According to Hochman and Tuli, the cervical myelopathy degeneration was usually progressed
silently with short intervals of progression, followed by a long period of time that symptoms were stable.
However, symptoms might also appear suddenly in the case of an acute disc herniation or after a neck injury.
Cervical myeloptahy due to degeneration manifests itself with very diverse clinical symptoms. From
cervical spine pain, shoulder arm pain to sensory disorders, movement disorders and sphincteric dysfuntions. In
the study of 31 patients, all 31 cases had sensory disorders at different levels and 30 cases had movement

disorders.
There were 26 patients with transverse lesion syndrome, 5 patients with brachialgia and cord
syndrome, no patients with central cord syndrome, motor system syndrome and Brown-Sequard syndrome. This
result was consistent with literature. Central cord syndrome and Brown-Sequard syndrome only accounts for
about 5%, and will progress to transverse lesion syndrome in a short time.
4.2.5 The patient's condition at admission on a scale of JOA.
The average JOA score when hospitalized was 7.65 ± 4.28 (the lowest was 3 points, the highest was
13 points). Most patients in the study group had JOA score ≤ 12 points (96.8%.) The average preoperative JOA
score was 7.65, which was suitable for surgery indication. A JOA score of less than or equal to 7 indicates a
severe myelopathy, 8 to 12 was moderate myelopathy, and 13 or more was a mild myelopathy. The condition of
mild myelopathy is often treated internally, surgical indication when the JOA score was less than or equal to 12.
In Chenget al's study, the preoperative JOA score was 7.9 ± 2.8. Duetzmann et al reported a series of
studies on cervical laminoplasty (n = 4949), the average score of JOA before surgery was 9.91 ± 1.65 points. Our
study had no difference when compared to Cheng et al's study (p > 0.05) but there was a difference compared to
Duetzmann (p <0.01) but still consistent on the indication of surgery for patients with cervical cord compression
had JOA score lower 13 points
4.3 Image diagnosis
4.3.1 Imaging on routine X-ray
In our study, there were 31 cases with lordosis cervical spine (100%) before surgery, no patients had
kyphosis (the exclusion criteria of the study) because of contraindication to the method. The rang of motion of
cervical spine in our study before surgery was 45.26 ± 10,250, after surgery was 36.44 ± 13.710.
According to Chiba et al., 27% of patients with cervical myelopathy due to degeneration and 38% of
patients who had ossification of longitudinal ligaments were did laminoplasty complained about the restriction of
cervical spine activity. They had difficulty in turning their heads to look at the shoulder or look down at the toes.
Most patients had certain limitations in their daily activities.
According to Ratliff and Cooper, the significance of preserving range of motion of cervical spinal in
neurological recovery in laminoplasty remains a controversial issue in literature. For the purpose of preserving
the range of motion of cervical spinal, the laminoplasty procedure was between two options: either fixation of
the spine or laminectomy alone. Some authors claimed that limiting cervical spine movement had a positive
effect on neurological recovery in posterior decompression surgery. Kimura et al found that a 60% reduction in

cervical spine movement in laminoplasty patients reduced the dynamic factors that could cause damage spinal
cord such as spur and ligaments. Yoshida et al confirmed, limiting the range of motion of cervical spine might
prevent late neurodeterioration due to the calcification progression of posterior longitudinal ligament. Morio et
al, in another study also showed that limiting segment movement was also closely related to neurological
recovery. On the other side, Shaffrey et al confirmed the importance of preserving the movement of cervical of
laminoplasty surgery compared to anterior surgery or posterior surgery with fixation. Preserving cervical
movement for prevention of progressive degeneration in adjacent segments. Morimoto et al also confirmed the
importance of preserving the cervical spine movement. In their study, the rate of presever rang of motion of
cervical spine was 83%, equivalent to our study (p > 0.05).
In an overview of cervical laminoplasty developments and trends 2003-2013, Duetzmann et al also
found that there was still a debate about whether preserving the cervical spine movement was better compared to
fixation. It had not changed significantly compared to 10 years ago. The author argued that the assessment of
cervical movement required standard radiography to be difficult and inaccurate, especially in retrospective
studies. The quality of life of a patient might not be affected by a decrease in the cervical spine movement , so
one of the purposes of the laminoplasty surgery was preserving rang of motion of the cervical spine sometimes
without meaning. In our opinion, it is necessary to preserve the range of motion of cervical spine because it is
physiological and reduces the degeneration of the adjacent segments.
4.3.2 Magnetic resonance imaging
4.3.2.1 Number of stenosis level
In the study, there were 127 stenosis levels in 31 patients, an average of 4.09 levels for a patient.
Compared with Phan Quang Son, an average of 4.12 levels for a patient showed no difference (p> 0.05). When
there were 3 lvevels stenosis, some surgeons could still use the anterior procedure such as corpectomy, fixation,
bone graft. But when the cervical stenosis had from 4 levels or more, most surgeons used posterior surgery
procedure. The rate of patients with ≥ 4 levels in our study was 71%. In Cheng et al's study, the author selected
thelaminoplasty surgery for patients with 3 or more stenosis levels, with an average levels stenosis was 3.4 for
one patient.
4.3.2.2 Morphology lesion on magnetic resonance imaging
With 31 patients surveyed with magnetic resonance imaging (5 cases with dynamic magnetic

resonance imaging survey) before surgery, we found 100% of patients with bulging disc, 93.5% of patients with
yellow ligament hypertrophy. These are typical characteristics of degenerative disease.
There were 30 patients, accounting for 96.8% had high-signal intensity in magnetic resonance film on
T2-weighted, in which 4 patients had high-signal intensity on T1-weighted. According to some studies, lowsignal intensity on T2-weighted images was a predictor of neurological recovery. The group with high-signal
intensity on T2-weighted images had a higher recovery rate than the group without low-signal intensity on T2weighted images. In the Secer et al’s study (2017), the high-signal intensity T2-weighted group had a
significantly higher recovery rate of 73.5 ± 25.2% compared to the non high-signal intensity group on T2W of
37.1 ± 1.68%. Our study, the rate of high-signal intensity on T2-weighted was 96.8%, so the rate of neurological
recovery increased, also consistent with the literature. However, low-signal intensity on T1W and high-signal
intensity on T2-weighted images were associated with more severe clinical conditions as well as less


neurological recovery post-operative. These changes included myelomalacia, edema, glial cell proliferation, and
or demyelination. Earlier surgical interventions may be indicated for patients with these changes to halt or
restore spinal cord lesions.
For patients with clearly clinical symptoms of cervical myelopathy, but on the magnetic resonance
film from the basic posture did not clearly show the cause, the compression position, the dynamic magnetic
resonance was a good choice to clarify the diagnosis. So far there have been many studies in the world, showing
the diagnostic effectiveness of the method. According to Zeitoun et al, retrospective study of 51 patients with
cervical myolopathy were taken magnetic resonance imaging with 3 postures (flexion, neutral and extension).
The results showed that 22.5% of patients increased the number of lesions from 1 level in neutral position to 3
levels in maximum extension position. According to Zhang et al, took magnetic resonance imaging for 50
patients with cervical myelopathy concluded that the cervical myelopathy due to degeneration was the
combination of two factor, static and dynamic compression, in which dynamic compression factor played an
important role. In some patients, the image of a high-signal intensity on T2-weighted was only seen on the
flexion posture. Dynamic magnetic resonance imaging gave an accurate view the number of compression and a
better assessment of the degree of spinal canal stenosis, images of lesions in the spinal cord. With new
information that resonates from dynamic magnetic resonance imaging, it could change the treatment strategy for
patients. However, this issue is rarely mentioned in Vietnam.
In our study, 5 patients were given dynamic magnetic resonance imaging. Table 3.13 showed the
actual change in the number of stenosis on dynamic magnetic resonance imaging (increase from 1.4 to 3.8

levels). If there was no dynamic magnetic resonance, it was possible to choose anterior approach surgery in these
patients instead of choosing the posterior approach. This is a new point in our study, which helps to provide a
more comprehensive view of the diagnosis and from there to provide appropriate treatment options.
4.3.3 Computerized tomography images
Computerized tomography scanner could measure the diameter of the anterior-posterior cervical canal
correctly also clarified the diagnosis of ligament calcification. In our research, we only selected patients with
cervical stenosis due to degeneration, not choosing the ossification of longitudinal ligament so computerized
tomography was not really necessary in diagnosis. However, before surgery, we surveyed the computerized
tomography for 23 patients, measured the cervical canal diameter at each vertebra.
According to Kokubun and Sato [40], the an-posterior cervical canal diameter ≤ 12 mm was called
the spinal stenosis. In general, patients with cervical myelopathy due to degeneration, the diameter of the
cervical spine was usually lower than 12 mm. This was also consistent with domestic and foreign literature. In
our study, the proportion of patients with an-posterior diameters of cervical canal ≤ 12 mm met the rate of 100%
in C4, C6, 95.7% in C3 and C5. The average an-posterior cervical diameter at C4: 9.56 mm, C5: 9.57 mm and
C6: 9.94 mm. Compared theses indexs to Tran Ngoc Anh’s study, there was no difference.
According to Jiang et al, 61 patients underwent single door laminoplasty, 38 of them were used
titanium miniplate, 31 patients used suture only to fix the laminas. The group using titanium miniplate, the spinal
canal was expanded an average of 10.8 mm ± 1.7 mm pre-operative to 15.9 ± 1.6 mm (up 5.1 ± 0.5 mm) in at the
time of 12 months post-operative, more expander than the group using suture only 11.7 ± 1.1 mm ppre-operative
to 16.2 ± 1.4 mm after surgery (up 4.5 ± 0.6 mm). The difference was statistically significant with p <0.01.


The bone healing rate at the hinged side wass 100%, without pseudarthrosis, no spring back into the
spinal cord. According to Chen et al, 54 patients with cervical myelopathy underwent laminoplasty (29 patients
using titanium miniplate, 25 patients used suture to fixe laminas), the ratio of bone healing on the hinge side was
100% after 12 months follow up. Yang et al’s research used maxillo-facical titanium plate like our study, had
bone healing rate after 6 months was 98.67%. According to research by Jiang et al, patients underwent
laminoplasty using titanium miniplate showed the bone healing on the hinge side faster than the group of
patients underwent laminoplasty using suture.
4.4 Cevical stenosis due to degeneration: surgical treatment by laminoplasty

4.4.2 Cervical laminoplasty using maxillo-facial titanium miniplate
Laminoplasty was invented by Japanese authors in the 1970s. Basically, laminoplasty was divided into
two categories: single door and double door laminoplasty. The orginal single door laminoplasty was done by
Hirabayashi. Spinal canal was widen and fixed by unabsorbed sutures. However, the fixation by suture increased
the risk of spring back of laminas, pseudarthosis on the hinge.
Since 2009, at the 108 Central Military Hospital, we started single door laminoplasty method using
maxillo-facial titanium miniplate to treatment multilevels cervical stenosis. The advantages of this method were:
Reducing the risk of spinal cord injury when opening the laminas compared to using T-saw in double door
laminoplasty; Could be applied in patients with small processes, which could not be done by the method of
creating two hinges; Reducing surgery time because of reduced bone cutting and grafting or artificial materials;
Did not take iliac crest bone for bone grafting, so it did not cause pain at the post-surgical site; Application of
maxillo-facial titanium miniplate instead of specialized braces, easy to use, reduce surgical costs.
Maxillo-facial titanium miniplate, used for maxillary bone, cheekbone has 1 mm thick, 4.5 mm wide,
10 mm long, 2 mm diameter screw, 5 and 7 mm long self-drilling screws used in the study are products of
Biomet Microfixation - UK. The advantages of the plate is that it is easy to cut and ductile shape according to the
surface of the laminas and lateral mass. On the palte, there are many holes which are easy for choosing the fixed
position of the screw. Pointed and self-tapping screws are easy to screw into the laminas and lateral masses, no
need to drill holes before bolting, reducing the surgery time. The average surgery time in the study was 123.55 ±
33.84 minutes. Compare with the results of O'Brien et al (148.5 minutes) and Yang et al (145,07 minutes), using
the same method, our surgery time was shorter (p <0.01).
In our study, 31 cases underwent laminoplasty using titanium miniplate, no bone graft or artificial
materials graft to the open side of laminas. If bone graft itself is to take bone graft from posterior spine or pelvic
bone. In surgery, the bone must be cut to fit the grafting site, making the surgery time longer, increasing the risk
of complications. Some patients develop pain at the location of persistent pelvic bone crest, very uncomfortable
after surgery. Using alternative biological materials increases treatment costs. Other studies also showed no
difference in neurological recovery, bone healing rate and postoperative complications between the two groups
with bone grafting and no bone grafting on the open side.
Following the domestic studies, Vo Van Thanh was the first author who had done laminoplasty
techniques in Vietnam since 1995. He had improved Hirabayashi's technique. He used lateral mass screws, steel
suture to fix laminas, instead of using unabsorbed sutures as the original technique. This technique had led to a

new option suitable for social-economic and medical conditions in Vietnam. However, patients couldn’t take


magnetic resonance because of using steel suturet. We have not seen any research that reports about laminoplasty
technique using maxillo-facial titanium miniplate except 7 cases with our research facility. .
In the world today, there are many authors, especially Chinese, Hong Kong, Taiwanese, Korean
authors, who also use maxillo-facial titanium minplate to do laminoplasty. It reduces treatment costs, achieves
high efficacy, without complications related to instrument.
4.6 Surgical results
4.6.1 Evaluation of surgical results
4.6.1.2 Far results (at least 12 months after surgery)
The recovery rate in our study was 69.43 ± 2.62%. Compared with the results of Tung et al (2015), the
study of 29 patients, the follow-up period of 48 months, the recovery rate was 64%. There was no difference
when compared to our study (p> 0.05). According to Chen et al (2012), 32 patients underwent laminoplasy using
titanium miniplate with the follow-up time was 23.3 ± 7.2 months, the recovery rate was 57.48 ± 16 , 51% (p
<0.05). However, when compared to the study of Lee et al with the recovery rate was 47.23%, the recovery rate
in our study was significantly higher (p <0.01).

CONCLUSION


Over 31 cases with multilevels cervical myelopathy due to degeneration underwent laminoplasty using
maxillo-facial titanium miniplate, the average follow-up time was 37.68 ± 15.85 months. We draw the following
conclusions:
1. Clinical characteristics and imaging diagnosis of researched patients:
- Clinical characteristics: The average age of the study group was 56.84 ± 8.23 years, of which male /
female ratio was 2.1 / 1. The average duration of disease was 16.19 ± 20.84 months, with the common symptoms
of onset disease were numbness, sensory disorders of limbs, accounting for 51.6%. The reason why patients
were admitted to hospital was movement disoder, accounting 64.5%. Clinical symptoms when hospitalized are
neck pain, spreaded to the arrm (64.5%), movement disorders (96.8%) and sensory disorders (100%). Hoffman

signs (+) wase 83.9%, L’hermitte sign (+) was 12.9%. Other symptoms such as sphincter disorders was 67.7%,
autonomic nervous dysfunction was 6.5%. Transverse lesion syndrome was the most common clinical syndrome
(83.9%). Preoperative JOA score was 7.65 ± 2.48 points.
- About image diagnosis characteristics:
+ X-ray image showing the average preoperative lordosis angle of cervical spine was 22,35 ± 9,03 0,
average preoperative range of motion angle of cervical spine was 45.26 ± 10,25 0, Torg-Pavlov index was the
smallest at C5: 0.65 ± 0.08.
+ On the magnetic resonance image, the average number of cervical stenosis for a patient was 4.09.
Hypertensity signal on T2-weighted when took magnetic resonance imaging: 96.8%. Dynamic magnetic
resonance imaging showed that the number of cervical stenosis levels increased from 1.4 to 3.8 level compared
to took in neutral position in all 5 cases.
+ Computerized tomography images: The preoperative average anterior - posterior diameter of cervical
canal on computerized tomography in 23 patients were C3: 10.52 mm, C4: 9.78 mm, C5: 9, 57 mm, C6: 9.94
mm, C7: 11.63 mm. Proportion of patients with cervical canal diameter ≤ 12 mm: 100% at C4, C6; 95.7% in
C3C5 and 73.9% in C7.
2. Surgical results
- Image results: The range of motion of the cervical spine was preserved 84.37%, 100% patients had
good bone healing on hinge side, no patient had restenosis or laminas spring back.
+ Clinical results: The average JOA score at the end point of following up was14.42 ± 1.97. The recovery
rate was 69.43 ± 26.22%, of which the good and excellent results were: 83.9%, fair 9.7% and poor 6.5%.
Surgical complication of surgical was epidural tear: 3.2%. Long-term follow-up, there was 1 cervical kyphosis
case post-operative: 3.7%.
- There was a correlation between disease duration and recovery rate: The duration of desease in 12
months gave a better recovery rate than the duration of the disease over 12 months.
- Cervical laminoplasty using maxillo-facil was a safe and effective procedure and could be applied at
facilities with Neurosurgery Department and basic equipments of the specialty.