V.C - L - Gross Pathologies of the Vertebral Column - Spinal Tuberculosis, Scheurmann's disease, Ankylosing Spndylitis

Question 1

When was spinal tubercolosis first discovered? What is it also known as? What was the relationship between for the discovery of spinal TB?

Answer 1

Spinal TB - aka as Pott’s disease after being discovered by Sir Percival Pott - was discovered in 1779 He first discovered the relationship between tubercolosis spondylitis, kyphosis and paraplegia

Question 2

What bacteria is spinal tuberculosis caused by?

Answer 2

Spinal tubercolosis (STB) is the extrapulmonary manifestation of tuberculosis caused by mycobacterium tuberculosis - initially asymptomatic

Question 3

What percentage of cases of tuberculosis does STB account for?

Answer 3

STB accounts for 2% of all tubercolosis cases 15% of tuberculosis cases are extrapulmonary TB

Question 4

What types of inflammation is spinal TB said to be a combination of?

Answer 4

A combination of osteomyeltitis and arthritis involving multiple vertebrae

Question 5

What is the most commonly affected area of the spine by spinal tuberculosis? (try and rank the vertebral column in order of prevalence) What age groups is spinal TB more common in?

Answer 5

The lower thoracic spine is the most common area of involvement * Thoracic spine - 65% * Lumbar - 20% * Cervical - 10% * Thoracolumbar - 5% Spinal TB is more common in children and young adults

Question 6

What is the estimated increase in risk of developing spinal TB in patients with HIV?

Answer 6

Estimated 20-37 times greater risk of developing spinal TB in patients with HIV

Question 7

TB is estimated to affect 1.7 billion worldwide Despite this number, what percentage of the population contain the latent bacterium?

Answer 7

90-95% of the population contain the latent bacterium for tuberculosis - a debilitated immune system eg HIV, makes the occurrence of TB more likely

Question 8

What is the transmission of tuberculosis?

Answer 8

TB is spread through aerosol (airborne) transmission into the lungs

Question 9

Usually, any pathogen is stopped by the mucus membrane surrounding the airway. TB avoids this mucus lining. What cells then engulf the TB?

Answer 9

TB is engulfed by alveolar macrophages due to TB expressing foreign proteins on their surface and it is therefore phagocytosed

Question 10

What does the TB release which is necessary for to inhibit phagolysosomal formation? What does this allow for?

Answer 10

TB releases SapM (secreted acid phosphatase of M.Tubercolosis) and PknG (protein kinase G) which inhibits phagolysosomal formation which would normally break down the foreign bacteria and this allows MTB to survive and proliferate forming a localised infection

Question 11

What symptoms occur once a localised infection forms?

Answer 11

Once a localised infection forms, mainly asystemic and flu like symptoms appear

Question 12

What happens to the localised infection after 3 weeks? talk up until a ghon focus is formed

Answer 12

After 3 weeks, cell mediated immunity initiates immune cell coverage of the mycobacterium with lymphocytes which forms a granuloma to prevent spread The tissue within the immune cells then dies via aprocess called caseous necrosis (caseation) and now a ghon focus is formed

Question 13

TB can spread to nearby lymph nodes via immune cells from the Ghon focus or from direct extensions, resulting in the same process occurring. When the the immune cells from the ghon focus cause spread of the TB, what is this now known as? Where does it usually occur?

Answer 13

The Ghon focus + spreading immune cells to nearby lymph nodes is known as a Ghon complex and it usually forms in the subpleural area. Ghon’s complex is a lesion seen in the lung that is caused by tuberculosis. The lesions consist of a calcified focus of infection and an associated lymph node.

Question 14

What is the evolution of the ghon complex known as?

Answer 14

The ghon complex often undergoes fibrosis followed by calcification leading to what is known as a Ranke complex - which will form scars in the lung

Question 15

At this point in certain cases, where the ranke complex is formed, the immune system rids of the tb infection. However, in other cases, the tb remains latent in the “immune cell capsule”. With a compromised immune system, the reactivation can cause spread into the upper part of the lungs where it is believed that oxygenation is greater. What will now happen when the TB moves to the upper part of the lung?

Answer 15

With fibrous necrosis this time, cavities will form in the lung allowing the bacteria to disseminate, either through airways, haemategnously or lymphatically - leading to systemic military TB

Question 16

DESCRIBE THE PATHOGENESIS OF SYSTEMIC MILITARY TB?

Answer 16

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Question 17

What is the common spread of TB from the lungs to the vertebral column and how?

Answer 17

Haematogenous spread of MBTB commonly occurs through Batson’s venous plexus - valveless network connecting the deep pelvic veins and the thoracic veins to the internal vertebral venous plexuses However, lymphatic drainage to the para-aortic lymph nodes or arterial routes through arterial arcade, in the subchondral region of each vertebra can occur.

Question 18

Where does STB initially affect?

Answer 18

STB initially affects anterior structures of the vertebral column - anterior longitudinal ligament and the antero-inferior part of the vertebral body

Question 19

How does STB first appear in the vertebral column?

Answer 19

STB first appears antero-inferiorly then spreads to the centre of the vertebral body or disc It usually affects the (lower) thoracic region of the vertebral column

Question 20

What is the clinical presentation of STB?

Answer 20

* Weight loss * Local pain with stiff movement, swelling & effusion * Fever * Fatige * Night sweats * Paraparesis * Gibbus * Cold abscesses are present

Question 21

What can the reduction in body weight lead to? What is a cold abscess?

Answer 21

• Reduction in body weight can lead to muscle wasting A cold abscess refers to an absence that lacks intense inflammation usually associated with infection - found in deep tissue of the infection site

Question 22

Antero-inferior destruction reduces the intervertebral disk space and adjacent vertebral bodies, leading to collapse of the spinal elements. What does the anterior wedging of the vertebrae form?

Answer 22

The anterior wedging of the vertebrae can form a gibbus (localised kyphotic deformity >20 degrees saggital index) which has a characteristic angulation

Question 23

What does the inadequate size of the IV disc due to the antero-inferior destruction of the body/disc?

Answer 23

This can result in an increased risk of compression fractures due to the absence of the disc

Question 24

How is suspected STB diagnosed? (state how the two tests are carried out)

Answer 24

Mantoux test - tuberculin injection into the skin intradermally - previous exposure to TB allows the immune system to create a small localised reaction around 48-72 hours after creating a large induration and redness Interferon gamma (Ifn-y) release assay (IGRA) - usues blood samples to identify the bacterium - more specific to MBTB than other types of mycobacterium (mycobacterium bovis and leprae)

Question 25

Visual identification would include either Xray, MRI or CT When is each used?

Answer 25

Xray - mainly performed initially to patients with suspected TB - bone mineral density must be >70% for any lesions to be visible MRI - predominant test used in diagnosis - helps identify numerous presentations CT - more effective in identifying the shape and calcification of soft tissue abscesses

Question 26

What is looked for in an MRI and CT in someone with STB? (mnemonic - SADDER)

Answer 26

• Sclerosis - mainly visible using a CT
• Abscess - refers to cold abscesses or calcifications
• Disc space reduction - usually visible using a CT
• Destruction of the vertebral body
• Erosion of the vertebral body or osteoporosis
• Rarefaction - reduction of bone density (also reduction of nervous tissue)

Question 27

The treatment plan of STB depends on the presence of neurological complications If no neurological complications, what is the treatment?

Answer 27

If no neurological complications, a course of Anti-TB drugs consisting of rifampicin, isioniazid, pyraziname, ethambutol for 2 months, and then rifampicin and isioniazid for 6-18 months Different sites agree on 2 months of initial cocktail and then vary depending on how long for the final two drugs - between 6 and 12 months is most common

Question 28

If there are neurological complications, what is the treatment?

Answer 28

4 options * Posterior decompression and fusion with bone autografts * Anterior debridement/decompression and fusion with autografts * Anterior debridement/decompression and fusion, followed by simultaneous or sequential posterior fusion with instrumentation * Posterior fusion with instrumentation, followed by simultaneous or sequential anterior debridement/decompression and fusion

Question 29

What is the most common of the 4 methods of treating STB with neurological complications? * Posterior decompression and fusion with bone autografts * Anterior debridement/decompression and fusion with autografts * Anterior debridement/decompression and fusion, followed by simultaneous or sequential posterior fusion with instrumentation * Posterior fusion with instrumentation, followed by simultaneous or sequential anterior debridement/decompression and fusion

Answer 29

Anterior debridement/decompression and fusion with autografts

Question 30

A classification system was introduced in 2008 to allow choosing the option for treating STB to become easier What was this classifciation system?

Answer 30

Gulhane Askeri Tip Akademisi (GATA) classification

Question 31

This classification was introduced in 2008 as a practical guide for STB treatment based on clinical and radiological criteria; What is the clinicial and radiological criteria via which it is based on? What is the classification system known as again?

Answer 31

Kyphosis Saggital index Instability Neurological problems Abscess formation Disc degeneration Vertebral collapse Gulhane Askeri Tip Akademisi - GATA classification

Question 32

* Which vertebral level is more commonly associated with STB? * What do the SapM and PknG proteins released by MBTB inhibit? * MBTB spread to the vertebral column is mainly hematogenous. - True or false * Where is vertebral destruction commonly first identified?

Answer 32

* Which vertebral level is more commonly associated with STB? - THORACIC REGION * What do the SapM and PknG proteins released by MBTB inhibit? - PAHGOLYSOSOMAL FORMATION * MBTB spread to the vertebral column is mainly hematogenous. - True or false = TRUE via Batson’s * Where is vertebral destruction commonly first identified? - ANTERO-INFERIOR VERTEBRAL BODY

Question 33

Which drug is NOT associated with non-surgical treatment of STB? 1. Streptomycin 2. Pyrazinamide 3. Metformin 4. Rifampicin

Answer 33

1. Metformin

2 months rifampicin, isoniazid, pyrazinamide, ethambutol (or streptomycin)

6-18 months rifampicin and isoniazid

Question 34

Lets now discuss Scheurmann’s disease What is scheurmann’s disease? What is its inheritance? What age group does it most commonly develop in?

Answer 34

Scheurmann’s disease is an abnormality that arises during development of the spine resulting in a dorsal kyphosis It is an autosomal dominant inheritance and most commonly develops in 13-16 year olds

Question 35

SD affects males and females equally Its aetiology is unkown but thought to be multifactorial What are some of the proposed causes?

Answer 35

Inadequate absorption of nutrients from foods Infection Shortening of the sternum Excess axial load on the spine due to heavy lifting

Question 36

What appearance does the dorsal kyphosis give the patient? What other condition must be assessed due to its high association with SD?

Answer 36

The dorsal kyphosis gives the patient a humback appearances Scoliosis must also be assessed in the patient due to its high association with SD

Question 37

What region of the vertebral column is mainly affected in SD? What is the spinal abnormality that occurs in SD?

Answer 37

The thoracic region is mainly affected The posterior aspect of the vertebrae grows normally whilst the anterior aspect grows abnormally resulting in a wedge-shaped vertebrae with irregular epiphyseal centres Red arrows showing the anterior abnormalities

Question 38

Apart from the anterior abnormalities occurring in the vertebral body resulting in the wedge shaped vertebrae and irregular epiphyseal plates, what other abnormalities occur?

Answer 38

There are also endplate abnormalities as nucleus pulposus extrudes through the endplate & into vertebral body and this appear as incongruous depressions of endplate - these are Schmorl’s nodes Red arrows show the anterior abnormalities White arrows shows herniating IV disc

Question 39

When is Scheurmann’s disease more painful? When does the progression of SD stop?

Answer 39

Scheurmann’s disease is more painful when in the lumbar region and stops when the axial skeleton is fully mature

Question 40

What is the clinical presentation of Scheurmann’s disease?

Answer 40

Pain in the thoracic region and surrounding area Patients appear hunched due to the thoracic kyphosis Difficulty exercising Restricted movements - particularly extension of the back

Question 41

What do es the MRI and Xray show? Same patient

Answer 41

Top image – MRI shows the hunched patient due to excessive thoracic kyphosis as well as lower thoracic Schmorl’s nodes and anterior wedging of thoracic vertebrae Bottom image (same patient) – Xray shows the associated slight scoliosis with Scheuermann’s with the mid and lower thoracic vertebrae

Question 42

What is used to diagnose Scheurmann’s disease? What is the diagnostic criteria? (three criterion)

Answer 42

Xray, MRI and CT scans sued to aid diagnosis Diagnostic criteria * Hyperkyphosis greater than 45 degrees * Irregular vertebral end plates with loss of disc space height * Wedging of 5 degrees in three or more sequential vertebrae Schmorl’s nodes may be present but are not required as part of the diagnostic criteria

Question 43

Treatment for is dependent on the symptoms and severity the patient presents with What is the treatment options for pain and mobility?

Answer 43

Ice NSAIDs Avoid heavy lifting Posture brace Physiotherapy exercises - * Improve range of motion - as much extension as possible * Focus on muscles used for movement and posture of back * Exercise must be specifically suited for the individual’s needs

Question 44

Use of posture brace (to encourage muscle activity & keep the back in as much extension as possible) What may happen after stopping using the brace? Why is it important to undertake physiotherapy exercises which are specific to the individuals needs right away?

Answer 44

Recurrence of pain and immobility may occur after stopping using the brace Period of rest may lead to muscle weakness/lack of fitness so it is important to recieive guidance on activities to regain muscle strength straight away

Question 45

What is used for the treatment of severe cases of Scheurmann’s disease? (dont incude surgery)

Answer 45

Use of * Casting * Spinal brace * Recumbency on a rigid bed

Question 46

Surgery is rarely required for SD but sometimes may be advised When is this and what is the surgery?

Answer 46

Surgery rarely required unless - Significant kyphosis - greater than 75 degrees Persistent spinal pain (despite other Tx options) Unacceptable cosmetic appearance Neurological deficit Spinal fusion is the most common surgery of choice when surgery is required *

Question 47

What is the image showing? When is surgery used in Scheurmann’s disease?

Answer 47

Image shows two thoracic vertebrae have been fused together with nails - preventing back pain and movement between the two bones Surgery is used when * Significant kyphosis - greater than 75 degrees * Persistent spinal pain despite other treatment options * Unacceptable cosmetic appearance * neruological deficit

Question 48

* What is the mode of inheritance in Scheuermann’s? * What is the diagnostic criteria for Scheuermann’s disease on imaging? * Scheuermann’s disease mostly affects the thoracic spine? True or false * What aspect of the vertebrae grows abnormally?

Answer 48

* What is the mode of inheritance in Scheuermann’s? - AUTOSOMAL DOMINANT * What is the diagnostic criteria for Scheuermann’s disease on imaging? Hyperkyphosis greater than 45 degrees Irregular vertebral endplates with loss of disc space height Wedging of 5 degrees or more in three sequential vertebrae * Scheuermann’s disease mostly affects the thoracic spine? True or false = TRUE * What aspect of the vertebrae grows abnormally? - ANTERIOR ASPECT

Question 49

Which treatment for pain is NOT associated with Scheuermann’s disease? 1. Soft tissue massage 2. Non-steroid anti-inflammatory drugs 3. Vertebral resection 4. Ice

Answer 49

3. Vertebral resection is not associated with treatment for pain

Question 50

What is ankylosing spondylitis?

Answer 50

This is a chronic inflammatory disease primarily attacking the axial skeleton and its adjacent structures

Question 51

AS belongs to a group of inflammatory rheumatic disorders known as spondylarthropathies What are spondylarthopathies?

Answer 51

Spondylarthopathes are related to other inflammatory disorders of the joints however as they test negative for the immunoglobulin rheumatodi factor there are known as seronegative inflammatory disorders - aka spondylarthropathies

Question 52

What is rheumatoid factor?

Answer 52

Rheumatoid factor is an antibody which reacts with circulating gamma globulins in the blood to form immune complexes that contribute to the disease process in inflammatory disorders

Question 53

AS is of unknown aetiology, however has a strong genetic component. What is the particular gene present in 90% of cases of AS?

Answer 53

This would be human leucocyte antigen-B27 HLA-B27

Question 54

Although most HLAs protect your body from harm, HLA-B27 is a specific type of protein that contributes to immune system dysfunction What are HLAs?

Answer 54

HLAs are proteins found on the surface of white blood cells which help the immune system identify the differences between healthy body tissue and foreign substances that may cause infection

Question 55

What is the prevalence of AS? What age group is affected?

Answer 55

It affects between 1in100 and 1in200 people Age of onset is mid 20s with males being more commonly affected Those who tested positive for the HLA-B27 antigen have a lower average age of onset than those who test negative.

Question 56

Where does fusion of the spine begin in ankylosing spondylitis?

Answer 56

Fusion begins with the inflammation of the insertion points of the ligaments - the enthesis The enthesis is the connective tissue between ligament/tendon/joint capsule to bone. where the ligaments, tendons, or joint capsules attach to bone

Question 57

Enthesitis helps distinguish AS from seropositive inflammatory disorders Enthesis involvement where is a hallmark feature of AS? What leads to ossification at the enthesis?

Answer 57

Enthesis involvement at the spine and sacroiliac joints is a hallmark feature of ankylosing spondylitis Healing and repairing off the inflamed ligaments eventually leads to scarring which can potentially lead to ossification

Question 58

What are the bony growths developing from the scarred ligaments known as? Are these bony growths pathognomonic of ankylosing spondylitis? What will eventually happen to these bony growths?

Answer 58

The bony growths developing from the scarred ligaments are known as syndesmophytes The bony growths are not pathognomonic of AS These bony growths can eventually fuse together leading to fusion of the joint - ankylosis

Question 59

Lateral radiograph of lumbar spine showing marginal syndesmophytes (arrows). – paper actually is discussing hypoparathyroidism but nicely shows what syndesmophytes look like What is the main presenting symptoms of AS?

Answer 59

The main symptoms is inflammatory back pain (IBP)

Question 60

What features help to differentiate IBP from MBP?

Answer 60

IBP * Morning stiffness >30 minutes * Improvement of back pain with exercise * Awakening in the night due to back pain but only in the second half of the night * Alternating buttock pain

Question 61

Apart from the IBP, what are the other clinical presentation features of AS?

Answer 61

Reduced movements of the cervical and lumbar spine - specifically the lumbar and sacroiliac joints Arthritis - commonly in the hips, shoulders & knees Loss of chest expansion as the disease progresses - inflammation of cartilage of rib insertion to sternum - costochondritis Fatigue

Question 62

What are some extra-articular manifestation of ankylosing spondylitis?

Answer 62

* Acute anterior uveitis - sudden onset of pain, redness, blurriness, photophobia * Psoriasis * Inflammatory bowel disease * Associated cardiovascular features * AS is often associated with osteoporosis

Question 63

When is IBD associated with AS? What are some of the asosciated cardiovascular features of AS? Why is there an increased risk of vertebral fractures in patients with AS?

Answer 63

IBD is associated with more severe cases of AS Associated cardiovascular features - aortic valve incompetence, conduction abnormalities, increased risk of MI Increased risk of vertebral fractures - due to osteoporosis, spinal rigidity, kyphosis of the spine

Question 64

Lets discuss what happens if AS is left untreated Describe how a patient develops the ‘question mark’ posture

Answer 64

Pain and inflammation will first reuslt in loss of lumbar lordosis followed by a thoracic kyphosis followed by hyperextension of the neck in an attempt to look forwards - the question mark posture

Question 65

Lets discuss what happens if AS is left untreated What is the radiographic feature seen which occurs due to the fusion of the vertebral bodies due to extending sydesmophytes? What happens to movements? What may acute anterior uveitis lead to?

Answer 65

The radiographic feature seen is called Bamboo spine There is a progressive loss of spinal movements in all directions due to Bamboo spine Acute anterior uveitis may lead to permanent blindness

Question 66

The relationship between arthritis and underlying inflammation is not always clear Most patients remain fully functional and able to work. Severe long-standing disease can often lead to early retirement due to an inability to work and increased mortality due to cardiovascular complications. When is there a worse prognosis in AS? (4 points)

Answer 66

Worse prognosis if * Eryhrocyte sedimentation rate >30 * Age of onset

Question 67

What is the ESR? (erythrocyte sedimentation rate)

Answer 67

It is a non specific measure of inflammation Measures the rate at which red bloood cells settle out of plasma in one hour - more cells/hour means greater inflammation Inflammation causes the cells to clump together and settle faster

Question 68

No radiological findings are diagnostic of anklyosing spondylitis and therefore two main diagnostic criteria are used What are these criteria?

Answer 68

The 1984 Modified New York Criteria Assessment of Sponylo-Arthritis international Society (ASAS) - classification criteria for Axial Spa

Question 69

What is axial SpA? What does ASAS stand for again? What does this criteria help combat?

Answer 69

* Axial SpA includes patients wth axial disease both with and without radiographic findings * ASAS - Assessment of Spondylo-Arthritis international Society * A classification criteria for axial SpA This classification system does not rely on radiographic findings and therefore helps to combat the 7-10 year delay in AS diagnosis

Question 70

The modified new york criteria has radiological criteria as well as clinicial criteria What is the radiological criteria? State what each stage shows

Answer 70

Radiological criteria * Bilateral sacrolitis >/= grade II or * Unilateral sacrolitis grade III or IV Grading of sacroiliitis Grade 0: normal; Grade 1: suspicious changes; Grade 2: minimal abnormality – small localized areas with erosion or sclerosis, without alteration in the joint width; Grade 3: unequivocal abnormality – moderate or advanced sacroiliitis with one or more of: erosions, evidence of sclerosis, widening, narrowing or partial ankylosis; Grade 4: severe abnormality – total ankylosis.

Question 71

What is the clinical criteria in the modified new york criteria?

Answer 71

* Low back pain and stiffness for at least 3 months improved by exercise and not relieved by rest * Limitation of motion of the lumbar spine in both the saggital and frontal planes * Limitation of chest expansion for normal ranges of sex and age

Question 72

How is definite AS diagnosed with the 1984 modified new york criteria?

Answer 72

Patient must have radiological criterion + two of three clinical findings Probable diagnosis if all three criterion are present alone or Radiological findings but no clincial findings not satisfy criterion

Question 73

What is the radiological and clinical presentation criterion for the modified new york criterion again?

Answer 73

Radiological criterion * Bilateral sacrolitis =/> grade II or * Unilateral sacrolitis grade III or IV Clinical presentation criterion * Low back pain and stiffness for >3 months improved on exercise but not at rest * Limitation of motion of the lumbar spine in both the saggital and frontal planes * Limitation of chest expansion relative to normal values for age and sex

Question 74

ASAS Classification Criteria for Axial SpA What age must the patient be and duration of disease must the patient have? What is the difference between the imaging and clinical arm for diagnosis of ankylosing spondylitis?

Answer 74

Imaging arm - Sacrolitis on imaging (satisfying modified New York criteria or active inflammation highly suggestive of Axial SpA) + >/=1 SpA features Clinical arm - HLA B27 + >/= 2 SpA features Patients with back pain >/= 3 months and age at onset <45 years

Question 75

What is the sensitivity and specificity of the ASAS criteria for axial SpA?

Answer 75

Sensitivity - 82.9% Specificity - 84.4% The imaging arm (the patients who had evidence of sacroiliitis on either MRI or X-raus, plus at least one further SpA feature) showed specificity - 97.5%, but it has a low sensitivity - 66.2%. The clinical arm (presence of HLA-B27 plus at least two further SpA features) has ~80% for both sensitivity and specificity.

Question 76

Treatment for AS is not curative and aims to reduce symptoms and pain What is the triple attack most cases involve?

Answer 76

Exercise, physiotherapy and medication

Question 77

What is mainstay of the medication options? What happens if patients are non responsive to this?

Answer 77

Mainstay is NSAIDs - and opioids Biological agents are licensed for use in patients who are non responsive to NSAIDs * Tumour necrosis factor (TNF)-alpha inhibitors (Anti-TNFs) * Disease-modifying anti-rheumatic drugs (DMARDs)

Question 78

What is TNF? What is the downside of DMARDs in AS treatment?

Answer 78

TNF is a chemical produced by cells when tissue becomes inflamed - it Is an acute phase proteins which further promotes inflammation - anti-TNFs inhibit this Disease-modifying anti-rheumatic drugs (DMARDs) – only helps treat pain and inflammation in joints other than the spine

Question 79

When is surgery used in AS?

Answer 79

Joint replacement surgery if the joint is severely affected ie hip Spinal correction surgery (spinal osteotomy) if : * Significantly affecting patients quality of life * Severe or progressive despite optimal non-surgical management

Question 80

* Which HLA is commonly found in AS and what percentage of patients test positive? * Which criteria enables early diagnosis of AS? * Syndesmophytes are pathognomonic of AS * Worst prognosis for AS if… * Spinal correction surgery is considered when…

Answer 80

• HLA B27 found in 90% AS
• ASAS Criteria allows for early diagnosis of AS
• Syndesmophytes are not pathognomonic of AS
• Worst prognosis if - ESR >30, Age of onset
• Spinal correction surgery- Significantly affecting patient quality of life Severe or progressive AS despite optimal non-surgical Mx