Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 94 pot

Spectrum of osteoporotic vertebral fractures aSimple compression fracture with ongoing pain 2 months after onset.bNon-union 6 months after fracture of T11.. Risk factors for VBCF Age pr

Figure 2 Bone mineral density

Distribution of bone mineral density (BMD) in

healthy women aged 30 – 40 years [46].

ence population This so-called T-score is the number of SDs that the bone

den-sity is above or below the average value for the reference population Four general

diagnostic categories have been distinguished:

BMD can be differentiated into four categories

) normal: BMD equal to or more than –1 SD (T-score –1)

) osteopenia: BMD between –1 SD and –2.5 SD (T-score <–1)

) osteoporosis: BMD less than –2.5 SD (T-score <–2.5)

) severe osteoporosis: BMD less than –2.5 SD in the presence of one or more

fragility fractures.

For diagnosis, measurements of BMD at the hip and the lumbar spine are the gold

standard

Besides the diagnostic use of bone densitometry, these measurements have an

additional prognostic value with respect to fracture probability: the age-adjusted

relative increase in risk (e.g., of vertebral fracture) is 2.3 for every one SD

decrease in lumbar BMD [61]

Classification of Vertebral Body Compression Fractures

Unlike traumatic fractures, osteoporotic vertebral body fractures can be difficult

to diagnose on conventional radiographs The fracture patterns often do not fit

into fracture classifications known from spinal trauma [60] For this purpose

morphometric criteria were established for diagnosing incident fractures (Fig 3)

[28, 68] From the spine surgeon’s perspective, the assessment of an osteoporotic

fracture includes consideration of the following criteria ( Fig 4):

From a surgical perspective, the differentiation of acute and old fractures is most important

) acute and subacute single level fractures

) fractures with persistent instability

) (multiple) fractures with progressive/creeping vertebral collapse and loss of

sagittal balance and posture

) vertebral fractures with subsequent spinal stenosis/neural compression

Figure 3 Morphometric criteria

Typical morphometric criteria for diagnosing incident fractures: Melton

[68] defines a vertebral fracture as present if any of the ratios AH/PH, MH/

PH, PH/PH1, PH/Ph-1 of a vertebra are less than 85 % of the mean ratio in

normal women for that vertebral level Semiquantitative evaluation

describes a mild grade 1 deformity as a 20 – 25 % reduction in anterior,

middle and/or posterior height and a 10 – 20 % reduction in area A

mod-erate grade 2 deformity is defined as a 25 – 40 % reduction in any height

and a 20 – 40 % reduction in area, and a severe grade 3 deformity is

defined as a 40 % reduction in any height and area [28].

Figure 4 Spectrum of osteoporotic vertebral fractures

aSimple compression fracture with ongoing pain 2 months after onset.bNon-union 6 months after fracture of T11 The persisting instability causes pain during change of position.cFractures of multiple vertebrae are responsible for loss of posture and neck pain in order to compensate for the deformed thoracic spine.dFracture of T7 with concomitant spinal canal encroachment and compression of the spinal cord.

Clinical Presentation History

The medical history appears crucial for the clinical appraisal However, the symptoms are often misinterpreted Overall, only about one-third of all vertebral

Less than 10 % of VBCFs

necessitate in-hospital

treatment

fractures come to clinical attention and less than 10 % necessitate admission to hospital The incidence of vertebral fractures is underreported The low rate of

clinical vertebral fracture diagnosis may be related in part to the lack of a trau-matic precipitating event (only 25 % of vertebral fractures result from falls), and

Figure 5 The scale of

vertebral fractures

Data according to Cooper et

al [16].

therefore the symptoms are often misinterpreted as muscle strain instead Most

clinically diagnosed fractures (84 %) are detected during investigation for back

pain; the remaining 16 % without pain may be old fractures that are detected

incidentally during a radiological work-up (Fig 5) [92]

Most VBCFs cause acute sharp localized pain

The cardinal symptoms of acute osteoporotic vertebral fractures are:

) acute onset, often initially breathtaking

) sharp localized, girdle like pain

) sensation of a crack in the back

Pain persistence indicates further collapse risk

Fractures are most often associated with physical activity (lifting of weights)

However, they can also occur spontaneously In the majority of patients, the pain

subsides spontaneously within a couple of weeks Persisting pain is a hallmark of

ongoing instability with progressive loss of vertebral body height

Severe positional pain indicates putative non-union

Therefore, patients should be monitored carefully with repeated X-ray

examina-tions Severe mechanical back pain for weeks or even months during positional

changes (e.g., getting up from the supine position) leads one to suspect a non-union

with persisting instability This can be verified by comparing the standing X-ray

with an investigation taken with the patient in the supine position such as an MRI

scan (Fig 6) However, a hyperextension cross table view depicts the difference

between the standing and supine positions more accurately Diffuse mechanical

back pain of the whole thoracic or lumbar spine can be found in severe osteoporosis

More and more frequently, we observe patients complaining about

claudica-tion like symptoms or sciatica after a VBCF Usually, the symptoms subside while

lying down and are accentuated in the upright position If a narrowing of the

spi-nal caspi-nal occurs, the patient can present with:

) radiculopathy

) claudication symptoms

) myelopathic symptoms with gait abnormalities and/or ataxia (thoracic

frac-tures)

a b

Figure 6 Positional differences

Patient with persisting pain 6 months after a T11 fracture The pain is severe during the change from supine to sitting position.aThe radiograph shows a nearly complete collapse of T11 with a severe kyphotic deformity.bIn the MRI scan there is some degree of spontaneous correction of the kyphosis in comparison to the standing X-ray, which demon-strates the segmental instability.

The history should also include a search for risks of a new osteoporotic fracture

Table 2 Risk factors for VBCF

Age

) previous fragility fracture

) low bone mineral density (BMD, T-score)

) glucocorticoid therapy

) high bone turnover

) family history of hip fracture

) poor visual acuity

) low body weight

) neuromuscular disorders

) cigarette smoking

) excessive alcohol consumption

) long-term immobilization

) low dietary calcium intake

) vitamin D deficiency According to Kanis [45]

height of patients This can be used as a reference in further follow-up controls.

The sagittal balance of the spine should be assessed because a sagittal

decompen-sation indicates an increased risk of progressive kyphosis Furthermore, a

thor-ough general medical assessment is required to rule out secondary causes of the

fracture and to establish a differential diagnosis

Diagnostic Work-up

Imaging Studies

Standard Radiographs

Standard radiographs remain essential for diagnosis

The investigation of choice remains a standing X-ray of the region of interest in

two planes If there is a concordance of the clinical and imaging investigations, no

further examinations are needed The comparison with older X-rays can be

help-ful (patients may have had previous chest X-rays) If the fracture pattern or the

patient’s history (red flags, see Chapter 6) is not clear, further imaging studies

are necessary “Instability” can be identified by comparing a standing X-ray with

the MRI or CT scan taken with the patient in a supine position Alternatively, a

hyperextension cross table view can provide the same information (Fig 6) This

provides further information about the potential for achieving some reduction

when the patient is positioned prone during surgery [66]

Computed Tomography

CT best depicts the bony anatomy

A CT scan can be useful for assessment of the bony anatomy If the exact fracture

pattern is difficult to appraise, a CT scan with reformatted pictures in the sagittal

and coronal planes should be performed The evaluation of tumors with a CT

scan shows the exact bony destruction and is recommended before cement

rein-forcement is considered

Magnetic Resonance Imaging

MRI differentiates acute and old fractures

An MRI investigation is recommended if the findings on standard X-rays

are not obvious, especially if there are preexisting fractures of which the age is

not known The MRI though allows fresh osteoporotic fractures to be

iden-tified

MRI differentiates tumor and osteoporosis

Also a metastatic lesion can be ruled out on the MRI scan The T2-weighted

(T2W) image can depict a bone marrow edema which can be verified further

with a fluid sensitive sequence [e.g., short tau inversion recovery sequence

(STIR),Fig 7,Table 3] An osteoporotic fracture is differentiated from another

pathologic fracture if the pattern of signal change in the T1W and especially in

the T2W image is not as homogeneous A high signal intensity in T1W images

(resembling fat) argues for an osteoporotic fracture Sometimes imaging is not

Figure 7 Differential diagnosis

Comparison of MR findings of a metastatic lesion (rhabdomyosarcoma) and an osteoporotic fracture with T1- and T2-weighted images as well as with STIR sequences (seeTable 2).

Table 3 MR findings

Osteoporotic fracture Dark signal Clear signal, located close to

the fractured endplate

Clear signal involving the whole vertebra

Metastatic lesion Different patterns depending

on the underlying tumor

Signal change includes the major part of the vertebra

Clear signal of the whole vertebra

able to give a definitive answer In these cases, a CT-guided biopsy should be obtained prior to cement reinforcement

Radionuclide Studies

Radionuclide studies are

helpful in differentiating

tumors and generalized

bone disease

When a tumorous lesion or another generalized bone disease is suspected, a bone scan is indicated Furthermore, if a patient is not suitable for an MRI scan (e.g., pacemaker, claustrophobia), a bone scan can be performed to detect a fresh frac-ture Of note, a bone scan shows a high sensitivity but is not specific

Densitometry

If a patient presents with an osteoporotic spine, the BMD should be determined There are two methods for the assessment of the BMD

High-Resolution Quantitative Peripheral Computed Tomography

High-resolution quantitative peripheral computed tomography (hrpQCT) is a

more sophisticated method for the assessment of the BMD It allows a volumetric

measure of the bone density (mg/cm3) and can differentiate between cancellous

and cortical bone Despite the higher sensitivity of this method compared to

DEXA, which allows small changes of bone density and structure also to be

detected, it did not gain widespread use in clinical practice and is of more

impor-tance in the scientific field [19]

Bone Biopsy

A bone biopsy is required

in equivocal cases of a tumorous lesion

A biopsy is indicated if the preexisting cause of a fracture cannot be determined

in order to rule out a tumorous lesion It is not performed routinely although the

incidence of unexpected cases of plasma cell dyscrasia in a series of 142 patients

undergoing a kyphoplasty procedure was 3 % [96] In rare instances, assessment

of bone metabolism necessitates a biopsy

Laboratory Investigations

The laboratory work aims to rule out secondary osteoporosis and to investigate

the bone metabolism:

) alkaline phosphatase: Raised serum levels are found in the presence of an

increased bone turnover or mineralization disorders In osteoporosis, the

values are usually within the normal range or slightly raised

) osteocalcin: plays a role in the mineralization of the osteoid Increased

levels are found in renal failure and during treatment with calcitriol

) desoxypyridinoline: This substance is released during bone resorption and

secreted by the kidneys and can be traced in the urine

evalu-ation of different aspects of bone metabolism disorders

Table 4 Laboratory assessment

Level 1 (exclusion of secondary osteoporosis):

Ca, P, alkaline phosphatase, osteocalcin, creatinine, bilirubin, SGOT, SGPT, BSR, serum and

urine immunoelectrophoresis, blood cell count, urine status

Level 2 (clinical suspicion of secondary osteoporosis):

25(OH)D3(malabsorption), parathyroid hormone, T4, TSH, testosterone, 1,25(OH)2D3(renal

osteodystrophy)

Level 3 (dynamics of bone metabolism):

Osteocalcin (bone formation parameter), desoxypyridinoline/creatinine ratio (bone

resorp-tion parameter)

Non-operative Treatment Conservative Fracture Management

Carefully monitor patients

to avoid progressive

kyphotic collapse and sagittal imbalance

Treatment of VBCF is empirical Only about one-third of all fractures come to

clin-ical attention and less than 10 % necessitate hospital admission (Fig 5) [16] In the latter group, however, a high percentage become chronically painful due to non-union or spinal deformity [16, 92] Bed rest for a few days and pain medication are the first measures of treatment Bracing may be applied, but this is often not suit-able in the older age group and the effect is questionsuit-able [51] The first aim of con-servative treatment is to monitor the patient and avoid a collapse of a vertebral body with consecutive kyphosis and loss of sagittal balance Pain is the crucial parameter If there is any doubt, serial radiographic controls should be performed

Medical Treatment

Every patient with VBCF

should be evaluated

by an osteologist

Patients with fractures after inadequate trauma are likely to be osteoporotic Besides the treatment of the fracture, patients should be evaluated by an osteolo-gist with regard to a formal assessment of bone metabolism and adequate medi-cal treatment

Osteoporosis requires

appropriate systemic

medical treatment

Treatment of osteoporosis focuses on agents that:

) prevent bone loss ) increase bone mass The main goal of conservative treatment is to reduce the number of fragility frac-tures Osteoporosis, however, is a multifactorial disease, and skeletal fragility results from various factors Thus, achievement of optimal bone metabolism should be the aim throughout life, by age-specific non-pharmacological inter-vention first and adequate medication where needed

In the past 10 years, large double-blind placebo-controlled trials have been performed to assess the efficacy of medical treatment in postmenopausal women with incident vertebral and non-vertebral fractures as a primary endpoint

) restoration/maintenance of calcium and vitamin D metabolism ) inhibition of bone resorption by biphosphonates

The relative fracture risk is reduced 30 – 60 % by these drugs The absolute risk reduction is between 5 % and 10 % Out of 1 000 women with osteoporosis, about

Table 5 Pharmacological treatment for fracture prevention

+++ strong evidence, ++ good evidence, + some evidence for the efficacy of treatment to pre-vent fractures (in addition to the effects of calcium and/or vitamin D based on RCT [20]),

± equivocal, 0 no effects, – negative effects.

a Evidence derived mainly from observational studies.

b Effect on hip fractures not documented.

150 will show a VBCF within one year With medical treatment the number of

fractures will be about 80 (9 %) The absolute risk reduction is 6 %, and the relative

Approximately 15 %

of individuals continue

to experience pain despite osteoporosis treatment

risk reduction is 60 out of 150 (40 %) [20] (Table 6) However, as many as

one-third of patients continue to experience pain Approximately 15 % of individuals

continue to sustain fractures despite therapy Furthermore there is a

consider-able number of non-responders and non-compliant patients [20, 24, 58, 83]

Medical treatment includes ( Tables 4, 5):

) calcium

) vitamin D

) bisphosphonates

) raloxifene

) hormone replacement

) parathormone

A calcium intake of at least 1 g per day should be achieved and is supplemented

if dietary intake is not sufficient Vitamin D intake is about 200 – 400 IU per day

Operative Treatment

General Principles

The majority of VBCFs respond well to non-operative treatment However, about

one-third of vertebral fractures become chronically painful [16] and 10 % need

hospital admission [92] However, the number of patients who need surgical

treatment remains obscure The indications for and the goals of surgical

treat-ment are (Table 7):

Table 7 Indications and goals for surgical treatment

) Mechanical pain ) Stabilization of the spine/vertebra

) Claudication/sciatica ) Decompression of the spinal canal

) (Severe) deformity ) Restoration of anatomy

Surgical Principles

The surgical principles applicable for the treatment of VBCFs depend on:

) fracture location

) type of fracture

) number of involved vertebrae

) compromise of neural structures

The spectrum of surgical options includes:

) simple percutaneous cement reinforcement (vertebroplasty) ) restoration of vertebral body height by kyphoplasty or lordoplasty ) open surgical intervention with decompression and instrumentation ) combined procedures with internal fixation and cement reinforcement

Vertebroplasty

Over the last decade, the approach towards osteoporotic VBCF has changed The possibility of percutaneous cement injection into the vertebral body offers a new and extremely efficient treatment option The technique is rather simple from a spine surgeon’s perspective However, the critical aspect of the treatment repre-sents cement leakage Following the technical recommendations (Tables 8, 9), the procedure can be performed safely

Vertebroplasty is indicated

after failed non-operative

treatment

The indications and contraindications for vertebroplasty (VB) are listed in

to osteoporosis after non-operative treatment has failed

In this group of patients, percutaneous reinforcement provides a major pain improvement in more than 80 % of cases and prevents the further vertebral

col-Table 8 Key points of surgical technique

) high quality C-arm ) direct cement application with small syringes (1 cc, 2 cc)

) guidewire ) cement with high radiopacity

) large diameter cannulas (8G) ) Cement with high/adapted viscosity

Table 9 Steps of surgical technique

) positioning and monitoring of patient, i.v line

) image control previous to draping, marking of levels to be treated

) local anesthesia in line with the pedicle (unless general anesthesia is used)

) stab incision and preliminary placement of guidewire(s)

) readjustment and definitive placement of guidewire(s)

) placement of filling cannulas

) preparation of cement according to recommendations of producer, distribution into small syringes

) cement application with adequate viscosity, high viscous cement is inserted with the aid

of 1 cc syringes or the trocar

) cannula removal after curing of the cement

Table 10 Indications for vertebroplasty

) ongoing pain for more than 2 weeks after occurrence of a new fracture

) severe pain; patients remain bedridden for more than 4 days

) progressive compression fractures of one or multiple vertebrae with subsequent loss of posture

) non-union with persisting instability (Kummel-Verneuil disease)

) combined procedures with internal fixation in severe osteoporosis

Table 11 Contraindications for vertebroplasty

) pain unlikely to be related to a fracture

) infection

) blood clotting disorders

) neurological compromise

) impaired visibility during surgery

) poor general state of patient, unable to stand in prone position

) if an open procedure appears more appropriate