Discectomiesinlumbosacral disc herniation was first described byMixter and Barr in 1934 as acombination of laminotomy,disc removal, and neural decompression.AfterLove 1939 andCasper 1977
Trang 1Discectomiesinlumbosacral disc herniation was first described byMixter and Barr in 1934 as acombination 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 theminimum was discovered In 1997, Foley proposed a new method usingdilators with increasing diameters toapproach via paraspinal muscles with support of endoscope and special systems This method made theposterior approach in discectomies genuinely ‘minimally invasive’
In Vietnam, spinal surgery, especially minimally invasive spinal surgery, has only been paid attention todevelop in recent years According to VISTA network from the National Agency for Science andTechnology 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 Of493,413 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:
Trang 21 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 discherniation
Content: 128 pages in 4 chapters:
Trang 3The thesis includes 25tables, 10charts, 55figures, 141references (18in Vietnamese, 122in English, 1 inGerman).
Trang 4Chapter 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 laserand radiofrequency (RF) in minimally invasive treatment of disc conditions Minimally invasive spinalsurgery, especially minimally invasive discectomy,has been evolving rapidly in recent years
Minimally invasive discectomies using the Minimal Exposure Tubular Retractor (METRx) systemwas 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 theTLIF surgery using the METRx system To 2004, there have been over 6000 patients treated with theMETRx system in about 500 surgical centers
METRx is a method using the dilators with increasing length and diameters to approach via theparaspinal muscles Its strength is to preserve muscular and tendon structures at midline The METRx withQuadrant system have more strengths: adequate space, sufficient lighting, and applicable for migrated
Trang 5herniation 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 invasiveoperations, some approaches have been applied in clinical practice, such as percutaneous disc decompressionwith laser or RF, or lumbosacral endscopic discectomy Son DN et al performed lumbosacral endscopicdiscectomy in 70 patients Thach NV et al applied RF in treatment of cervical and lumbosacral discherniation Duyet TC et al performed percutaneous disc decompression with laser in 10 years (1999-2009) in3,173 patients (age 14-91) with total intervened discs of 5,909 It can been seen that surgical centersspecialized in spinal surgery have been implementing minimally invasive techniques, but studies on surgeryusing 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 – threesuperior components including 2 superior articular processes, 2 transverse processes, and 2 pedicles; andthree inferior components including 2 laminae, 2 inferior articular processes, and 1 spinal process The onlycomponents that lie at the same level of the inferior border are the junctions between the lamina and thepedicle
Trang 6From inferior to superior, there are three floors as described: floor 1 (disc), floor 2 (intervertebralforamen), and floor 3 (pedicle).
Depending on the position of the migrated disc, we will direct the dilators to the area under the support
1.3.1 Clinical signs and symptoms:
Two major syndromes: Lumbar syndrome (low back pain, paraspinal localized pain, limited range ofmotion of the lumbar spine) and Nerve-root syndrome (pain radiating to the area supplied by the nerve,rootstimulating 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
Trang 7border 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 openlaminectomy, exposureand transdural discectomy.Love (1939) performed posterior discectomy withoutlaminectomy
1.4.2.Minimally invasive discectomy with METRx and Quadrant
In 2003, the METRx system (Medtronic Inc.) was introduced Together with video andmicrosurgicalmicroscope,the system has spread the technique widely all over the world The lateral approach is direct tothe location of the decompression The increasing-in-diameter dilators put inside one another help dilate theparaspinal muscles, and the last dilator is connected to the flexible arm fixed to the operating table The lastdilator can be an 18-mm or 22-mm rounded tube, a 4-piece X-tube, or QUADRANT – made from twosemicircular pieces that can be dilated along the spine and are connected to the cold lighting source by theoptical fiber cable
Trang 8Chapter 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:
Trang 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
Trang 10Minimally 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
Trang 11with 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
Mean age 41.8, mode at 32, highest rate at the age group 30 -49 (57,8%) Overweight and obese
Trang 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%) – 14patients (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
(2 %)
18(11,9 %)
1(0,7 %)
22(14,6 %)
Trang 13(11,3 %) (55,6 %) (11,3 %) (78,1 %)
(0,7 %)
6(4 %)
4(2,6 %)
11(7,3 %)
(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
(7,3 %)
8(5,3 %)
2(1,3 %)
21(13,9 %)
(27,2 %)
62(41,1 %)
5(3,3 %)
108(71,5 %)
(4,6 %)
8(5,3 %)
7(4,6 %)
22(14,6 %)
Trang 14(39,1 %) (51,7 %) (9,3 %) (100 %)
Table 3: Relationship between herniation type and
preoperative leg NRS
(10,6 %)
71(47 %)
10(6,6 %)
97(64,2 %)
(3,3 %)
37(24,5 %)
12(7,9 %)
54(35,8 %)
(13,9 %)
108(71,5 %)
22(14,6 %)
151(100%)
Table 3: Relationship between herniation type and
preoperative back NRS
(9,3 %)
69(45,7 %)
7(4,6 %)
90(59,6 %)
(4,6 %)
39(25,8 %)
15(9,9 %)
61(40,4 %)
Trang 15Total 21
(13,9 %)
108(71,5 %)
22(14,6 %)
151(100 %)
Table 5: Relationship between legNRSanddegenerative grade
(7,9 %)
81(53,6 %)
4(2,6 %)
97(64,2 %)
(6,6 %)
37(24,5 %)
7(4,6 %)
54(35,8 %)
(14,6 %)
118(78,1 %)
11(7,3 %)
151(100 %)
Table 5: Relationship between back NRS and degenerative grade
(8,6 %)
70(46,4 %)
7(4,6 %)
90(59,6 %)
Trang 16(6 %) (31,8 %) (2,6 %) (40,4 %)
(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 ofthe 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
Trang 181-month postop ODI 6-month postop ODI
(11,9 %)
3(2 %)
0(0 %)
21(13,9 %)
0(0 %)
0(0 %)
(57 %)
22(14,6 %)
0(0 %)
104(68,9 %)
4(2,6 %)
0(0 %)
(6,6 %)
12(7,9 %)
0(0 %)
14(9,3 %)
7(4,6 %)
1(0,7 %)
Table 11: Age-weighted improvement using ODI
p < 0.05
Trang 19Chart 1: Changes of back pain severity with time
Table 12: Improvement of back NRS and herniation type
Trang 20(9,3 %) (45,7 %) (4,6 %)
(4,6 %)
39(25,8 %)
15(9,9 %)Postop
(13,9 %)
108(71,5 %)
22(14,6 %)
(0 %)
0(0 %)
0
0 %
Table13:Improvement of back NRS and degenerative grade
7(4,6 %)
(6 %)
48(31,8 %)
4(2,6 %)Postop
(14,6 %)
118(78,1 %)
11(7,3 %)
(0 %)
0(0 %)
0(0 %)
Trang 21Chart2:Changes of leg pain severity with time
Trang 22Table 12: Improvement of leg NRS and herniation type
Preop
(10,6 %)
71(47 %)
10(6,6 %)
(3,3 %)
37(24,5 %)
12(7,9 %)Postop
(13,9 %)
108(71,5 %)
21(13,9 %)
(0 %)
0(0 %)
1(0,7 %)
Table 15: Complications
Trang 23Cerebrospinal fluid leakage 0 0
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%)
Trang 2493 of 151 (61,6 %) patients have moderately and severely reduced function 2 patients’ functioniscompletely reduced.
Preoperative leg pain:
Every patient has leg pain before surgery 65 patients (43%) developed leg pain in a period of>12months, only 11patients (9,3%) developed leg pain in a period of<1 month
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
Trang 2559%, while the intervertebral foramen floor is only 9%.The most common site isfloor I, central area (42patients, 27,8%) Floor III, central areahas 26 patients (17,2%) The highest rate is seen in the central areaandlateral 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 reducedfunction – 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 Backpain >5 points is mostly seen in patients with disc extrusion or disc migration (32,4%).In the group of discextrusion and disc migration, the rate of patients with leg pain <5 points is much higher than those with legpain>5 points
Pain severity and degenerative grade
78,1% patients with disc degeneration grade III have leg pain Among these, 81 patients (53,6%) haveleg 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