Nghiên cứu đặc điểm lâm sàng, chẩn đoán hình ảnh và kết quả phẫu thuật trượt đốt sống thắt lưng đơn tầng do khe hở eo TT TIENG ANH

AND TRAINING MILITARY MEDICAL UNIVERSITY TRAN HONG VINH RESEARCH ON CLINICAL FEATURES, DIAGNOSTIC IMAGING AND RESULTS OF SINGLE-STAGE LUMBAR SPONDYLOLISTHESIS SURGERY DUE TO SPONDYLOLYSI

AND TRAINING

MILITARY MEDICAL UNIVERSITY

TRAN HONG VINH

RESEARCH ON CLINICAL FEATURES, DIAGNOSTIC IMAGING AND RESULTS OF SINGLE-STAGE LUMBAR SPONDYLOLISTHESIS

SURGERY DUE TO SPONDYLOLYSIS

Specialty: Surgery

ABSTRACT OF THE DOCTORAL THESIS IN MEDICINE

HA NOI - 2021

THE MILITARY MEDICAL UNIVERSITY

Science instructor: A.Prof PhD NGUYEN VAN THACH

Reviewer 1: A.Prof PhD Nguyen Le Bao Tien

Reviewer 2: A.Prof PhD Tran Cong Hoan

Reviewer 3: A.Prof PhD Nguyen The Hao

The thesis is defensed in front of the University Thesis Council at Military Medical University

At: on the (date) of (month), 2021

The thesis may be found at:

- Vietnam National Library

- Library of Military Medical Academy

Spondylolisthesis (SPL) is a phenomenon of displacement of the uppervertebra compared to the adjacent lower vertebra accompanied by complexpathological changes such as fracture of the pars, degenerative disc jointmass, and proliferation causing narrowing of the spinal canal and thesynovial hole leading to spinal instability and nerves compression Lumbarspondylolisthesis due to many reasons, including spondylolysis accounts for4-8% of the population and often unstable Diagnostic imaging plays animportant role in the early diagnosis of this type of pathology In Vietnam,the majority of cases of SPL due to spondylolysis when being hospitalizedfor treatment have symptoms of nerve compression, lumbar spine pain due

to instability after a long time, affecting the ability to work and quality oflife However, currently in Vietnam are mainly researches on diagnosis andtreatment of spondylolisthesis in general

On the other hand, in the surgery of treating SPL due to spondylolysis,two compulsory criteria are optimal anatomical manipulation, firm fixationand effective nerve decompression Considering these two criteria, recentlypublished studies in the world have demonstrated the superiority inmanipulation, good bone fusion, firm fixation and effective nervedecompression of the PLIF method

Therefore, we conduct the topic: "Research on clinical features,

diagnostic imaging and results of single-stage lumbar spondylolisthesis surgery due to spondylolysis" with two goals:

1 Describing the clinical and visual characteristics of unilateralspondylolisthesis caused by spondylolysis

2 Evaluate the results of single-stage spondylolisthesis surgery due tospondylolysis by using the method of rods and screws fixation combinedwith disc decompression, intervertebral fusion

MEANING OF THESIS

The thesis deals with research on single-level isthmic spondylolisthesisdue to pars fracture, this is a problem of high practical significance in thecurrent period Therefore, the thesis has made new contributions in spinesurgery as follows:

+ Affirming the superiority and irreplaceable practical value of PLIFsurgery in isthmic spondylolisthesis when new spinal surgery methods aredeployed and applied in the specialty

+ Contributing to providing a deeper understanding of techniques ofmanipulation, decompression, and fusion in surgery for isthmicspondylolisthesis cases in general and cases with slippage in particular

THESIS STRUCTURES

The thesis has 109 pages, Chapter I Introduction (33 pages), Chapter II Subject and Method (23 pages), Chapter III - Results (22pages), Chapter IV -Discussion (26 pages), Conclusions (1 pages) The thesis has 43 tables, 43pictures, and 12 charts The thesis has 136 references, include 8 Vietnamesereferences and 126 English references

-CHAPTER 1: OVERVIEW 1.1 Research history

1.1.1 In the world

Lumbar spondylolisthesis was mentioned by Herbinaux in 1782 ThenKilian came up with a definition and the term spondylolisthesis (SPL) In 1950,MacNab was the first to introduce a classification system of SPL Then, Wiltse

in 1957 and Newman in 1963 gave a classification of SPL including 5 types.However, these classifications are different and inconsistent Therefore, theseauthors agreed with each other and made a new classification which wasreported in 1976 at the international conference on spine named Wiltse -Newman - MacNab divided SPL into six different categories Some studies haveshown a significant relationship between SPL and BMI, age and lordosis of thespine According to research by Avanzi O., and colleagues, the rate of SPL mostcommonly encountered in L4L5 level, accounts for 47.6%; then to the L5S1level with the rate of 23.8%; the other is a combination of both L4L5 and L5S1levels

In terms of diagnosis, SPL due to many different causes has diverseclinical manifestations, no specific symptoms, so it is often confused withdisc herniation and spinal stenosis Therefore, diagnostic imaging plays aparticularly important role and has made great breakthroughs in the accuratediagnosis of SPL

In terms of treatment, in 1933 Burns first described surgical treatmentusing bone fusion with anterior intervertebral fusion combined with graftingtechnique to treat SPL at the L5-S1 level Then, a number of authors suchas: Lane and More, Briggs and Milligan, Cloward, Watkins, Gill, Harringtonand Tullos reported that the treatment of SPL by different surgical methodsobtained positive results and positively worked on the basis for later surgicalmethods In particular, good manipulation, firm fixation is the foundation forstrong bone fusion and nerve decompression, thereby allowing to achieveoptimal efficiency in surgery for SPL Bone grafting has many techniquesapplied such as: spondylolysis cleft bone grafting, posterolateral bonegrafting, combined posterolateral grafting and intervertebral bone graft,anterior and posterior intervertebral bone graft West et al reported 90% ofbone healing results in bone grafting patients using an internal immobilizerbecause the spine is fixed immediately after surgery, so the process of bone

resection is favorable, increasing the rate of rate of bone healing In general,all direct bone fusion methods are considered to be relatively safe andeffective.

1.1.2 Vietnam

In Vietnam, the diseases of the spine in general and the SPL in particularhave been mentioned and discussed from the 50s of last century However, itwas not until the second half of the 20th century that the surgical methods ofMSG really developed thanks to the technology and the means of fixing thespine through pedicles to be applied, opening up the research and treatmentdirection for this type of pathology Since then, the researches on surgicaltreatment of SPL began to be mentioned and deployed Currently, SPL has beencarried out routinely in major departments of nerve - spine across the country

1.2 Applied anatomy of the lumbar spine

1.2.1 Lumbar vertebrae surgery

Each vertebra consists of the main components of the vertebrae, thebody, the vertebrae arch and the foramen The pedicle attaches to theposterior 2/3 at L1 - L5 with wedge angle from L1 - L5 (5° - 15°) Thetransverse diameter of the pedicle is smaller, more important than thelongitudinal diameter, and increases gradually from L1 to L5 This is animportant anatomic feature in determining the point and entry of the archedscrew fixing method to create stability for all 3 columns The pedicle isstronger and more stable than the body and is the strongest part of thevertebra that can withstand the force of rotation, stretching and tilting to theside of the spine Therefore, most of the means of fixing the spine in theworld are used for screwdriving through the pedicles The parsinterarticularis is the intersection of the transverse process, lamina and twofacet joints of a vertebral body, which can form a cleft, causing a loss ofposterior arch continuity, which is the main cause of spondylolysis Thereare two forms of pars damage: cleft and pars damage The majority ofpatients have only one level of pars damaged, but can also be found atseveral levels of the spine

1.2.2 Neurologic anatomy of the lumbar region and related structures

Nerve roots go from the spinal canal below the pedicle out through theintervertebral foramina and near the top of the vertebral pedicle just below

In which, the correlation of position between the nerve roots passingthrough the intervertebral foramina and the disc is divided into four differentpositions: the shoulder, the anterior, the axillary, the unrelated type

The Kambin triangle - "safety triangle" is limited by: the outer edge infront is the exit root, the lower edge is the upper edge of the lower vertebra,behind by the upper joint of the lower vertebra and the inner edge is the rootpass This is a safe area to interfere with the disc when using surgical

instruments in the spine The understanding of the safe zone is necessary sothat when we intervene in this area when root decompression, bone graftingwill minimize complications such as root damage, tear of dura matter.

1.3 Pathogenesis and classification of lumbar SPL.

+ Injury to the spine can cause pedicle fracture, fracture of joints,fracture pars, damage the posterior column, leading to unstable spinecausing SPL

+ Theory of Genetics: Epidemiological studies show that the rate ofspondylolysis is stable in a lineage, an ethnic group

1.3.2 Classification of spondylolisthesis

Based on the classification of Newman, Macnab, in 1976 Wiltse synthesized andcategorized SPL into six different types: congenital numbness, spondylolysis SPL,degenerative SPL, traumatic SPL, pathological SPL, post-operative SPL In which, theSPL due to spondylolysis includes:

+ Sub-group 2 A: Type of pars defect identified as due to fatigue fracture

+ Sub-group 2 B: This type of sliding pars is longer than normal Thiselongation is explained by the phenomenon of fractures and bone healingthat occurs continuously in the pars area

+ Sub-group 2 C: Injury that causes pars fractures leading to slippage

1.4 Clinical and diagnostic imaging in spondylolisthesis

1.4.1 Clinical lumbar spondylolisthesis

There are valuable clinical signs in assessing the state of spinalinstability, the majority of patients with SPL have clinical symptomsmanifested by two syndromes:

+ Spine syndrome: characteristics of movement-related pain and positiveladder sign

+ Nerve root compression syndrome: with regional manifestations of thepinched nerve root

1.4.2 Methods of diagnostic imaging

1.4.2.1 Standard X-ray

It is a simple and effective diagnostic method in detecting SPL Usuallyapply frontal, oblique, 3/4-lateral and dynamic X-rays to help assess the

unstable state of the spine, the degree of slippage of the vertebra and detectother spinal deformations In specific:

* Oblique position

Films at a tilted position are an effective method for assessing the degree

of SPL Meyerding based on a oblique-X-ray film divided SPL into fourdegrees:

+ Grade I: the upper vertebral column deviates within 1/4 of theanteroposterior diameter of the lower vertebral body

+ Grade II: the upper vertebrae slide from 1/4 to 1/2 of theanteroposterior diameter of the lower vertebral body

+ Grade III: the upper vertebrae slide from 1/2 to 3/4 of theanteroposterior diameter of the lower vertebral body

+ Grade IV: the upper vertebrae has displacement greater than 3/4 of theanteroposterior diameter of the lower vertebral body

On oblique X-ray of the spine, many angles have been determined to describe

in detail the anatomical lesions of the sacrolumbar spine of the patient that affectthe process of SPL Specifically, the most important indicators are:% of theslippage forwards according to Taillard, the sliding angle according to Boxall,% ofthe curvature of the sacral apex These three measurable indices allow anestimation of the risk of the sliding process High sliding angles with roundedsacral arches increase the risk of progressive slip especially in children

Oblique dynamic X-ray

Dynamic lumbar x-ray is a valuable method in determining theinstability of the spine segment Two main criteria for evaluating the bio-mechanics of the lumbar spine are slippage and angular folding

According to White A.A and Panijabi M.M to determine vertebralinstability based on the following indicators:

Front and posterior displacement: A is the sliding distance of the uppervertebra from the lower vertebra B is anteroposterior diameter of the uppervertebrae If A> 4.5mm or A / B x 100%> 15%, then the spine is unstable.Angle of rotation: the determination is based on the angle of folding andmaximum stretch, where A is the intervertebral angle at maximum flexion(positive angle), B is the extension angle (negative angle) If A-B> 150, then lost ofstability at L1L2, L2L3, L3L4 levels, if> 200 then the L4L5 layer unstable, if> 250

then L5S1 will be stability lost

* Lateral position

Most cases are easily detected with spondylolysis An x-ray image of thediscontinuity is a scotty dog Most patients have only one pars fissure at onevertebral level, but may also several levels of vertebrae According toHerkowitz H.N, lateral films can detect 19% of pars defects, while lateralfilm with reasonable angle can detect up to 84% of the spondylolysis

1.4.2.2 Computer tomography of the lumbar spine

Computerized tomography (CT) has a high sensitivity to detect bonedefects In which, it is possible to accurately detect the very narrow fractureline in the pars area, especially new pars fractures due to trauma, parsdefects as well as joint enlargement and anatomy of the pedicle (size,direction, curvature).

1.4.2.3 Magnetic resonance imaging of the lumbar spine

According to Clayton NK, and Rudiger K., typical images of SPL onMRI film include: images of the above SPL, spurious disc herniation,degenerative disc at the position of slipping and adjacent vertebrae, modic,tearing fibrosis cushion, narrowing of intervertebral foramina; osteoarthritis

on the upper facet joint, hypertrophy of the joints, stenosis of the spinal cordcompressing the cauda equina, low clinging spinal cord (rare) In patientswith spondylolyisis SPL, the distance from the posterior edge of thevertebral body sliding to the anterior margin of the posterior arch increases

on the slice through the midline, which is called a broad spinal sign This is

an important sign to distinguish between spondylolysis SPL anddegenerative SPL due to the accompanying spinal stenosis

According to Pfirrmann et al (2001) evaluated disc degeneration onMRI based on T2W film and divided into 5 degrees:

Grade I: disc is homogeneous, white signal intensity and normal disc height

Grade II: disc is inhomogeneous, white signal intensity, normal disc height

Grade III: disc is inhomogeneous, gray signal intensity, little decreaseddisc height

Grade IV: disc is inhomogeneous, gray to black signal intensity, discheight is greatly reduced

Grade V: disc is inhomogeneous, black signal intensity, loss of disc height

All structures from the simple to the complex of the spine can beassessed in detail on high resolution magnetic resonance film Furthermore,MRI is a non-intervention, uncomplicated diagnostic method Therefore,this is the most commonly used diagnostic imaging method to diagnose SPLalong with conventional X-rays

1.5 Some basic problems in lumbar spondylolisthesis surgery

Surgery of SPL with the aim of decompressing, manipulating, and firmlyfixing the sliding spine in order to restore maximum nerve function andstructure of the damaged spinal segment Research by Möller H andHedlund R has shown that the surgery of SPL in adults gives better resultsthan physical therapy

1.5.1 Indicated for surgery

- Indications for absolute surgery: nerve compression causes manifestations ofincreased nerve damage, progressive slide in children (elevation slide in children,hunchback and lumbar distortion)

- Indications for relative surgery: there are manifestations of nervecompression but adequate, systematically medical treatment in 6 weeks;Factors that cause spinal instability: pars defect; Neurological functiondecreases and does not improve with conservative therapy.

1.5.2 Pedicle screw

+ The position of the entry point of the lumbar vertebral pedicleaccording to Molinari R.W : is the intersection between a vertical linetangent to the outer edge of the upper joint with a horizontal line passing inthe center of the transverse process or 1mm below this point Clinically, thepedicle entry point is determined at the junction between the surface of theupper joint, the transverse process and the interarticular junctioncorresponding to the nipple process

+ Direction of screws on the horizontal plane at an angle of about 5º 10º at L1, 10º at L2 and 15º at L3 - L5

-+ The diagram of screwdriving includes straight diagram (consideringthe vertical plane of the pedicle screw direction parallel to the top surface ofthe body, ie the angle of down to 0º) and anatomical diagram (the screwdirection along the pedicle is about 20º - 25º down) In it, according toKuklo T.R Straight diagrams provide a superior biological mechanismcompared to screwdriving according to anatomical diagrams

1.5.3 The degree of manipulation of spinal deformities

The current view of correction of spinal deformities is relatively unified.The manipulation of spinal deformities in patients with low slippage grades

is less commonly reported For SPL with great slippage, the view to partiallyrectify the deformations of the spine contributes to increase the rate of bonehealing, reduce the rate of prosthetic joints and the secondary deviation isrelatively uniform In general, the authors have the view that they do not try

to rectify the maximum slip Complete manipulation of the deviations isdifficult to perform and comes with a higher risk of nerve damage Thegeneral principle of this technique is to stretch the spine to rectify theangular displacement and pull the vertebrae to slide out after themanipulation of slip deviation, then the manipulation technique is donemore easily and safely

1.5.4 Nerve decompression and bone fusion

In SPL, nerve compression can be caused by many reasons: herniateddisc, bony spine, upper posterior margin of the vertebral body, the fibrousorganization of the pars compresses nerve roots in the lateral region ordegenerative enlargement of the joints However, the site of nervecompression is more common in the lateral margins and intervertebralforamina regions According to Edelson J.G and surgical associates, need toperform concurrent bone grafting and decompression of pinched nerve

roots The degree of suppression is also a controversial topic Sincedecompression of a pinched nerve root often increases spinal instability, theextent of decompression depends on the type of technique used Authorswho do not have bone grafts or do not use bone fusion media generally donot release a root compression or only minimal release of compression JohnD.M and colleagues suggest that loose posterior arch removal is not enough

to release pinched nerve roots Decompression should include release ofpinched nerve roots in the intervertebral foramina, especially in patientswith neural root pain However, it should be noted that after the roots areidentified, all proliferating prosthetic joint tissue must be removed

Vertebrae is shown to be a method with a high rate of bone fused thanks

to its wide bone graft area and rich blood supply, in many studies it canreach 93% - 100 Vertebral body is the location near the axis of movement

of the spine, where about 80% of the pressure is applied to the spine.Therefore, this is the most physiological bone grafting technique, ensuringthe stability and conforming to the bio-mechanical properties of the spine.The result of bone healing eliminates movement between vertebrae, nerveroots are not stretched during movement, so it does not cause pain due tosticky scars There are two popular techniques: PLIF - Posterior LumbarInterbody Fusion and TLIF- Transforaminal Lumbar Intervertebral Fusion

In particular, the PLIF method has the advantage of thoroughlydecompressing and rectifying, especially for large SPL such as grade III,grade IV when TLIF method has no indication for intervention

Current bone grafting materials include two types that are commonly used andcombined in surgery: autologous bones and artificial materials such as bone cages,artificial implants, artificial bone powder

CHAPTER 2: SUBJECTS AND METHODS OF RESEARCH 2.1 Research subjects

The study was conducted on 51 patients diagnosed with single-storylumbar SPL and surgical treatment at the Department of Spinal Surgery, VietDuc Friendship Hospital from June 2015 to June 2019

2.1.1 Selection criteria

- Patients aged 18 years and over, have meticulously clinically examinedresults and have necessary paraclinical results qualified to diagnoseunilateral lumbar SPL due to spondylolysis, undergo surgery by the method:disc removal to decompress, inter-body bone grafting, spine fixation byscrews through the pedicle

The patients were evaluated and monitored at the time: whenhospitalized, immediately after discharge and the last visit (≥ 12 monthsafter surgery)

2.2.2 Sampling method and sample size calculation

The study applies the sample size formula for a ratio:

- d: Absolute accuracy, choose d = 15%

- p: The recovery rate of patients with lumbar SPL after surgeryaccording to research by Okuda S in 2014 was 73% [97]

Calculated with the formula, n = 34 In fact, 51 patients have beenselected to participate in this study

2.2.3 The method of data collection

Information collected according to the uniform medical record form includes:questioning, examination and assessment of patients before surgery; Participate insurgery and follow-up and treat patients after surgery; Directly examine andevaluate postoperative patients according to research records at the time: atdischarge and at the last visit for ≥ 12 months

2.2.4 Research content

Evaluate before surgery, after surgery at the time of discharge and thelast visit according to the criteria on the research diagram

2.2.5 Data processing and analysis

Data after being entered using Epidata 3.1 software was checked,cleaned, and analyzed using Stata 15.0 software

2.2.6 Ethics in research

The study was approved by the Board of Directors of Viet DucFriendship Hospital, Leadership Department of Spinal Surgery - Institute ofOrthopedic Trauma, with the consent of patients and their families Allpersonal information of the subjects participating in the study is confidentialand used only for research purposes

RESEARCH DIAGRAM

Lumbar spondylolysis SPL cases underwent PLIF

Gender Causes Symptoms VAS JOA ODI Xray During operation After operation

Slippage Pars defect Flexion angleExtension angle SlippageDisc degenerationFibrosis and defects of pars

Conventional X-ray Dynamic X-ray MRI Duration Blood infusion

Stenosis

Discharge (7-10 days) ≥ 12 months

JOA VAS ODI Fixation results Screws, grafts location Complications and sequelae

3.1 General characteristics of patients

3.1.6 Reasons for admission and location of lumbar spondylolisthesis

Figure 3.7 Reasons for admissionFigure 3.8 Location of lumbar spondylolisthesis

3.1.7 Medical treatment before surgery

Figure 3.9 Medical facilities selected for treatmet

3.1.8 Time of disease progression

Table 3.3 Time of disease progression

Table 3.4 Preoperative mechanical symptoms

Table 3.6 Preoperative examined symptoms

(%)