kết quả nghiên cứu một số đặc điểm sinh thái và tình hình gây trồng loài lò bo (brownlowia tabularis pierre), xoan mộc (toona surenii (blume) merr) và dầu cát (dipterocarpus condorensis ashton)

1
INTRODUCTION
Discectomiesinlumbosacral disc herniation was first described byMixter and Barr in 1934 as a
combination of laminotomy,disc removal, and neural decompression.AfterLove (1939) andCasper (1977),
spinal surgery was considered minimally invasive whena new procedure which reduced tissue injury to the
minimum was discovered. In 1997, Foley proposed a new method usingdilators with increasing diameters to
approach via paraspinal muscles with support of endoscope and special systems. This method made the
posterior approach in discectomies genuinely ‘minimally invasive’.
In Vietnam, spinal surgery, especially minimally invasive spinal surgery, has only been paid attention to
develop in recent years. According to VISTA network from the National Agency for Science and
Technology Information, to the end of 2012, there have been 137 articles about spinal issues; among these,
40 articles are about spinal surgery and one is related to minimally invasive surgery using dilators. Of
493,413 PhD theses in the National Library, 29 theses are related to treatment of spinal conditions; however,
there are no theses mentioning minimally invasive surgery using dilators.
This is a new approach in Vietnam, and the data about its safety and efficiency are limited. Hence, we
conduct a study on “Application of tubular retractordiscectomy for single-level lumbosacral disc
herniation in Viet Duc University Hospital” with two aims:
2
1. To describe the clinical and paraclinical characteristics of single-level lumbosacral disc
herniation,and
2. To evaluate the surgical outcome, indication and surgical protocol of the surgery of lumbosacral
disc herniation using dilators.
Contribution:
- A study with adequacy of diagnostic criteria and indication for surgery using dilators.
- Formulate the diagnostic approach and treatment indication of single-level lumbosacral disc
herniation.
Content: 128 pages in 4 chapters:
Introduction 3 pages
Chapter 1: Overview 33 pages
Chapter 2: Method 25 pages
Chapter 3: Results 26 pages

Chapter 4: Discussion 39 pages
Conclusion 2 pages
3
The thesis includes 25tables, 10charts, 55figures, 141references (18in Vietnamese, 122in English, 1 in
German).
4
Chapter 1
OVERVIEW
1.1. HISTORY OF MINIMALLY INVASIVE DISCECTOMIES
1.1.1. International
In 1975, Hijikata described the first case of percutaneous discectomy. Recent studies focused on laser
and radiofrequency (RF) in minimally invasive treatment of disc conditions. Minimally invasive spinal
surgery, especially minimally invasive discectomy,has been evolving rapidly in recent years.
Minimally invasive discectomies using the Minimal Exposure Tubular Retractor (METRx) system
was developed in 1994 and was first applied in 1997 by Medtronic Sofamor Danek Inc. (USA). In 2003,
the company was awarded the patent for the minimally invasive intervertebral fixation and proposed the
TLIF surgery using the METRx system. To 2004, there have been over 6000 patients treated with the
METRx system in about 500 surgical centers.
METRx is a method using the dilators with increasing length and diameters to approach via the
paraspinal muscles. Its strength is to preserve muscular and tendon structures at midline. The METRx with
Quadrant system have more strengths: adequate space, sufficient lighting, and applicable for migrated
5
herniation. Other applications are minimally invasive laminotomy, minimally invasive foraminotomy,
bilateral spinal canal opening by minimally invasive unilateral approach
1.1.2. In Vietnam
Lumbosacral discectomies have been implemented in recent years. Of the minimally invasive
operations, some approaches have been applied in clinical practice, such as percutaneous disc decompression
with laser or RF, or lumbosacral endscopic discectomy. Son DN et al performed lumbosacral endscopic
discectomy in 70 patients. Thach NV et al applied RF in treatment of cervical and lumbosacral disc
herniation. Duyet TC et al performed percutaneous disc decompression with laser in 10 years (1999-2009) in

3,173 patients (age 14-91) with total intervened discs of 5,909 It can been seen that surgical centers
specialized in spinal surgery have been implementing minimally invasive techniques, but studies on surgery
using dilators are limited.
1.2. ANATOMY RELATED TO MINIMALLY INVASIVE SURGERY
From the inferior border of the pedicle, the vertebrae can be divided into six components – three
superior components including 2 superior articular processes, 2 transverse processes, and 2 pedicles; and
three inferior components including 2 laminae, 2 inferior articular processes, and 1 spinal process. The only
components that lie at the same level of the inferior border are the junctions between the lamina and the
pedicle.
6
From inferior to superior, there are three floors as described: floor 1 (disc), floor 2 (intervertebral
foramen), and floor 3 (pedicle).
Depending on the position of the migrated disc, we will direct the dilators to the area under the support
of C-arm.
Some anatomic abnormalities of the lumbosacral spine are congenital bone deformities and lumbosacral
root abnormalities.
1.3.CLINICAL AND PARACLINICAL CHARACTERISTICS OF LUMBOSACRAL DISC
HERNIATION:
1.3.1. Clinical signs and symptoms:
Two major syndromes: Lumbar syndrome (low back pain, paraspinal localized pain, limited range of
motion of the lumbar spine) and Nerve-root syndrome (pain radiating to the area supplied by the nerve,root
stimulating signs, Lasègue sign, sensory disorder, motor disorder, deep tendon reflex disorder).
1.3.2. Imaging:
Plain spine X-raycan evaluate spine instability and the condition of the posterior arch.Lumbosacral CT
scancan provide better assessment of the bony structure and detect some abnormalities.Lumbosacral MRIcan
detect different types of disc herniation:disc protrusion (protrusion of the nucleus pulposus outside of the
7
border of the adjacent vertebrae); disc extrusion (extrusion of the nucleus pulposus outside of the fibrous
ring); anddisc migration (the nucleus pulposus is sequestrated and separated from the disc).
1.4.SURGICAL TREATMENT OF LUMBOSACRAL DISC HERNIATION

1.4.1. Open discectomy
Oppenheim and Krause (1909) andWilliam J.Mixterand Joseph Barr (1934) proposed open
laminectomy, exposureand transdural discectomy.Love (1939) performed posterior discectomy without
laminectomy.
1.4.2.Minimally invasive discectomy with METRx and Quadrant
In 2003, the METRx system (Medtronic Inc.) was introduced. Together with video andmicrosurgical
microscope,the system has spread the technique widely all over the world. The lateral approach is direct to
the location of the decompression. The increasing-in-diameter dilators put inside one another help dilate the
paraspinal muscles, and the last dilator is connected to the flexible arm fixed to the operating table. The last
dilator can be an 18-mm or 22-mm rounded tube, a 4-piece X-tube, or QUADRANT – made from two
semicircular pieces that can be dilated along the spine and are connected to the cold lighting source by the
optical fiber cable.
8
Chapter 2
METHOD
2.1. SUBJECTS:
151 patients, treated withminimally invasive discectomy using METRx and Quadrant in the Department
of Spinal Surgery –Viet Duc University Hospital, fromOctober 2008 toOctober 2011.
2.2. METHOD:
Study design: cross-sectional.
Sample size:convenient sampling, including all the eligible patients during the study time.
2.3. PLANNING:
2.3.1. Data collection:
Using a pre-designed study medical report.
2.3.2. Information collected before study:
Preoperative information:
+ General informatino: age; gender; occupation; past history.
+ Clinical characteristic:
9
*Lumbar syndrome: the Numerical Rating Scale to assess low back pain and leg pain;the Owestry

Disability Index.
* Nerve-root compression syndrome:sensory disorder, Lasègue sign, deep tendon reflex disorder.
* Muscle strength and sensory assessment: ASIA (2006).
+ Imaging:
Plain X-ray andbendingX-ray,lumbosacral MRI.
Treatment indication:
+ Surgical indication: disc hernation with cauda equina syndrome(emergency); disc herniation with
paralysis (due to compression).
+ Surgical indication with dilators:criteria are (1) single-levelherination; (2) herniation without
instability; (3) herniation without spinal stenosis; và (4) herniation with pain radiation to unilateral leg,
consistent wih the side of compression.
+ Exclusive criteria:Absolute contraindication- (1) Lumbar spine instability; (2) Spinal stenosis,
multiple-level disc herniation (≥3 level); and (3) Systemic diseases that are contraindicated to surgery.
Relative contraindication–previous surgery at the side of compression (recurrent herniation); coagulopathy;
>2-level herniation; and surgical center out of capabilities.
10
Minimally invasive discectomy with METRx and Quadrant:
Technical requirements:IntraoperativeC–arms (SIEMENS Pb r8 N40 fo90), METRx and Quadrant
system (Medtronic Inc), specialized surgical instruments.
Discectomy with dilators.
Early rehabilitation (48 hour postoperative). Wear lumbosacral back brace in 2 weeks.
Postoperative information:
Using the study medical report, after 6 and 12 months.
• Clinical:NRS, ODI, general outcome
• Imaging:MRI, bending X-ray.
• Time to back-to-work
• Ouctcome assessment based onmodified Macnab criteria.
2.4.DIAGNOSTIC AND TREATMENT APPROACH OF LUMBOSACRAL DISC HERNIATION
2.4.1. Preoperative assessment
Clinical: History taking and physical examination.

Imaging:Lumbosacral X-ray and MRI.
Surgery indicated when: (1) Herniation with cauda equina syndrome (emergency); (2) Disc herniation
11
with paralysis (due to compression); or (3) Failure of conservative treatment.
Operation timing:Emergent surgery forpatients with herniation with cauda equina syndrome; and
scheduled surgery forother patients.
2.4.2. Surgery
2.4.3. Postoperative assessment: early movement since the 1st postoperative day.
2.4.4.Monitoring after discharge: assessment after surgery, 6 months, and 12 months: NRS, ODI, general
outcome using the modified MacNab criteria, and time to back-to-work.
2.5. DATA ANALYSIS:SPSS 18.0
2.6. MEDICAL ETHICS
Patient’s information is protected in a confidential medical report and used only for scientific research.
Chapter 3
RESULTS
3.1. GENERAL INFORMATION
Mean age 41.8, mode at 32, highest rate at the age group 30 -49 (57,8%). Overweight and obese
12
(classified by BMI) 33,8%.
3.2. CLINICAL AND PARACLINICALCHARACTERISTICS
Timing of leg pain: >12 months – 65 patients; 6-12 months – 36 patients; 3-6 months – 14 patients; 1-3
months – 22 patients;and <1 month – 11 patients.
Preoperative NRS: Back: 4,3 ± 1.5 (max NRS: 7 points, 20 patients).Leg: 4 ± 1,2 (max NRS: 8 points,
36 patients).
Preoperative ODI: Mildly reduced function (<30%) – 0 patients; moderately reduced (30%-50%) – 59
patients (39%); severely reduced (50%-70%)– 78 patients (51,7%); and completely reduced (>70%) – 14
patients (9,3%).
Disc degenerative grade: Grade II – 14,6%;grade III – 78,1%; and grade IV – 7,3%.
Herniation type: protrusion – 13,9%; extrusion – 71,5%; and migration 14,6%.
Table 1: Relationship between degenerative grade

and herniation type
Degenerative
grade
Herniation type Total
Protrusion Extrusion Migration
II 3
(2 %)
18
(11,9 %)
1
(0,7 %)
22
(14,6 %)
III 17 84 17 118
13
(11,3 %) (55,6 %) (11,3 %) (78,1 %)
IV 1
(0,7 %)
6
(4 %)
4
(2,6 %)
11
(7,3 %)
Total 21
(13,9 %)
108
(71,5 %)
22
(14,6 %)

151
(100 %)
Location of herniation:L4-L5 and L5-S1 – 140 patients (92,7%); andL3-L4 – 11 patients. Disc floor –
59%; pedicle floor – 32%; and foramen floor – 9%.
Area of herniation (HOS): Central – 52% patients, duong ra– 26%, and intervertebral foramen – 22%.
3.2.3. Association between clinical signs and symptoms and imaging
Table 2: Relationship between herniation typeand ODI
Herniation type Reduced function Total
Moderate Severe Complete
Protrusion 11
(7,3 %)
8
(5,3 %)
2
(1,3 %)
21
(13,9 %)
Extrusion 41
(27,2 %)
62
(41,1 %)
5
(3,3 %)
108
(71,5 %)
Migration 7
(4,6 %)
8
(5,3 %)
7

(4,6 %)
22
(14,6 %)
Total 59 78 14 151
14
(39,1 %) (51,7 %) (9,3 %) (100 %)
Table 3: Relationship between herniation type and
preoperative leg NRS
Leg NRS Herniation type Total
Protrusion Extrusion Migration
<5 16
(10,6 %)
71
(47 %)
10
(6,6 %)
97
(64,2 %)
>5 5
(3,3 %)
37
(24,5 %)
12
(7,9 %)
54
(35,8 %)
Total 21
(13,9 %)
108
(71,5 %)

22
(14,6 %)
151
(100%)
Table 3: Relationship between herniation type and
preoperative back NRS
Back NRS Herniation type Total
Protrusion Extrusion Migration
<5 14
(9,3 %)
69
(45,7 %)
7
(4,6 %)
90
(59,6 %)
>5 7
(4,6 %)
39
(25,8 %)
15
(9,9 %)
61
(40,4 %)
15
Total 21
(13,9 %)
108
(71,5 %)
22

(14,6 %)
151
(100 %)
Table 5: Relationship between legNRSanddegenerative grade
Leg NRS Degenerative grade Total
II III IV
<5 12
(7,9 %)
81
(53,6 %)
4
(2,6 %)
97
(64,2 %)
>5 10
(6,6 %)
37
(24,5 %)
7
(4,6 %)
54
(35,8 %)
Total 22
(14,6 %)
118
(78,1 %)
11
(7,3 %)
151
(100 %)

Table 5: Relationship between back NRS and degenerative grade
Back NRS Degenerative grade Total
II III IV
<5 13
(8,6 %)
70
(46,4 %)
7
(4,6 %)
90
(59,6 %)
>5 9 48 4 61
16
(6 %) (31,8 %) (2,6 %) (40,4 %)
Total 22
(14,6 %)
118
(78,1 %)
11
(7,3 %)
151
(100 %)
3.3. SURGICAL OUTCOME
Average amount of intraoperative blood loss: 24± 8 (ml).
Operating time: 78 ± 23 (minutes); min 50 minutes, max 110 minutes.
Postoperative hospital stay: 3,9 ± 1,4 (days). >2 days: 86,1%.
General outcome using modified Macnab criteria: excellent and good – 86,1%; andbad – 3,3%.
BMI-weighted general outcome using modified McNab criteria: No significant differences between
patients with normal BMI and with overweight in the group ‘Excellent’. In the group ‘Good’, the outcome of
the patients with normal BMI is higher than those with overweight.

Table 7: Relationship between outcomeand timing of leg pain
Timing
Outcome
<3 months >3 months Total
Excellent 20 3 23
Good 94 13 107
Medium 4 12 16
Bad 1 4 5
17
Total 119 32 151
Table 8: Relationship between outcome and HOS
HOS
Outcome
Central Lateral recess Foramen Extra-
foramen
Total
Excellent 2 11 10 0 23
Good 63 22 20 0 105
Medium 13 5 0 0 18
Bad 3 1 1 0 5
Total 81 39 31 0 151
Table 8: Relationship between outcome and herniation floor
Floor
Outcome
I II III Total
Excellent 2 9 12 23
Good 70 4 35 109
Medium 12 1 1 14
Bad 4 0 1 5
Total 88 14 39 151

18
3.4. TREATMENT OUTCOME
Improvement using ODI:preoperative ODI and 12-month postoperative ODI are 52,9 and 22,7,
respectively (p<0.001).
Table 10: Improvement using ODI and herniation type
Herniation
type
1-month postop ODI 6-month postop ODI
Mod Sev Comp Mild Mod Sev
Protrusion
18
(11,9 %)
3
(2 %)
0
(0 %)
21
(13,9 %)
0
(0 %)
0
(0 %)
Extrusion
86
(57 %)
22
(14,6 %)
0
(0 %)
104

(68,9 %)
4
(2,6 %)
0
(0 %)
Migration
10
(6,6 %)
12
(7,9 %)
0
(0 %)
14
(9,3 %)
7
(4,6 %)
1
(0,7 %)
Table 11: Age-weighted improvement using ODI
Age ≤ 59 > 59
p < 0.05Preop ODI 54 ± 12,4 60 ± 19,8
Postop ODI 22 ± 5,1 24 ± 12,7
19
Chart 1: Changes of back pain severity with time
Table 12: Improvement of back NRS and herniation type
Back NRS Herniation type
Protrusion Extrusion Migration
Preop <5 14
(9,3 %)
69

(45,7 %)
7
(4,6 %)
20
>5 7
(4,6 %)
39
(25,8 %)
15
(9,9 %)
Postop
<5 21
(13,9 %)
108
(71,5 %)
22
(14,6 %)
>5 0
(0 %)
0
(0 %)
0
0 %
Table13:Improvement of back NRS and degenerative grade
Back NRS Degenerative grade
II III IV
Preop
<5 13
(8,6 %)
70

(46,4 %)
7
(4,6 %)
>5 9
(6 %)
48
(31,8 %)
4
(2,6 %)
Postop
<5 22
(14,6 %)
118
(78,1 %)
11
(7,3 %)
>5 0
(0 %)
0
(0 %)
0
(0 %)
21
Chart2:Changes of leg pain severity with time
22
Table 12: Improvement of leg NRS and herniation type
Back NRS Herniation type
Protrusion
Extrusion
Migration

Preop
<5
16
(10,6 %)
71
(47 %)
10
(6,6 %)
>5
5
(3,3 %)
37
(24,5 %)
12
(7,9 %)
Postop
<5
21
(13,9 %)
108
(71,5 %)
21
(13,9 %)
>5
0
(0 %)
0
(0 %)
1
(0,7 %)

Table 15: Complications
N %
Tearing of spinal cord membrane 3 1.9
Nerve root injury 2 1.3
Cauda equina syndrome 0 0
Incision infection 0 0
23
Cerebrospinal fluid leakage 0 0
No complications 146 96.8
Total 151 100
Chapter 4
DISCUSSION
4.1. GENERAL CHARACTERISTICS
4.2. CLINICAL AND PARACLINICAL CHARACTERISTICS
4.2.1. Clinical characteristics
Pain (usingNRS)
Back and leg mean NRS are 4,3 ± 1,5 and 4 ± 1,2, respectively, and have no significant differences.
Back and leg mode NRS are 6 and 5, respectively. 43% patients have a timing of onset of >12 months;
timing of <1 month only accounts for 9,3%.
Reduced function of the lumbar spine (using ODI)
Mean ODI is 52,9 ± 12,8 (%) (min 22%, max 72%).
24
93 of 151 (61,6 %) patients have moderately and severely reduced function. 2 patients’ functionis
completely reduced.
Preoperative leg pain:
Every patient has leg pain before surgery. 65 patients (43%) developed leg pain in a period of>12
months, only 11patients (9,3%) developed leg pain in a period of<1 month.
4.2.2. Imaging
Degenerative grade and age group:
Herniation type

Most common are the extrusion type (71,5%); the protrusion type accounts for 13,9% and the migration
accounts for 14,6%.
Disc protrusion is an early stage and surgery using METRx results in early recovery. Disc extrusion
requires surgery as soon as possible. Disc migration requires careful assessment of the location.
Relationship between degenerative grade and herniation type
Most common are grade III and extrusion.
Location of herniation
92,7% are at the level of L4-L5 and L5-S1. 7,2% are at the level of L3-L4. The disc floor accounts for
25
59%, while the intervertebral foramen floor is only 9%.The most common site isfloor I, central area (42
patients, 27,8%). Floor III, central areahas 26 patients (17,2%). The highest rate is seen in the central areaand
lateral recessare with 117 patients (77,4%) ; among these, the highest rates are floor I and III.
4.3. RELATIONSHIP BETWEEN CLINICAL AND PARA-CLINICAL CHARACTERISTICS
Herniation type and preoperative reduced function
None with mildly reduced function. Completely reduced – 9,2%; and moderately and severely reduced
function – 90,8%.
Herniation type and pain severity
35,8% with leg pain>5 points. 64,2% with leg pain <5 points. 59,6% with back pain <5 points. Back
pain >5 points is mostly seen in patients with disc extrusion or disc migration (32,4%).In the group of disc
extrusion and disc migration, the rate of patients with leg pain <5 points is much higher than those with leg
pain>5 points.
Pain severity and degenerative grade
78,1% patients with disc degeneration grade III have leg pain. Among these, 81 patients (53,6%) have
leg pain<5 points and 37 patients (24,5%) have leg pain>5 points.
Back pain is most seen in disc degeneration grade III; among these, back pain <5 points is seen in 70