INTRODUCTION:

Spinal
infections are mainly categorized depending on their anatomical site of
occurrence viz. the vertebral column, the intervertebral disk, the spinal canal
along with the tissues. The causes of spinal infections range from bacterial
organisms to fungal organisms and could be cause pre or post any surgical
intervention. Most of the acquired post-surgical infections occur within three
days to three months after the surgical procedure.

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The
most common form of vertebral infection is
vertebral osteomyelitis, characterized by severe back pain along with
fever, chills, prominent weight loss, difficulty in passing urine associated
with pain and neurological deficits. It could be caused due to direct open
trauma to the spine as well as acquired infection from the adjacent area and
soft tissues.

Intervertebral disk space
infections are categorized into – Adult
hematogenous i.e. spontaneous, childhood (discitis) and postoperative. It
involves the intervertebral area between the adjacent vertebral bodies. The
main symptoms include, sever back pain, restriction or apprehension to flex the
spine in children and fever. In post-surgical cases, pain reduces with bed rest
and immobilization but increases with any movement. If the condition is not
diagnosed at the right time and progresses, the pain cannot be managed by
medications.

Spinal canal infections include
spinal epidural abscess that is
characterized by infection in the space around the dura. Subdural abscess occurs in the space between the dura and the
arachnoid. Intramedullary abscesses are
the ones that occur within the spinal cord parenchyma. The infection is characterized
by the following phases: Severe back pain with fever and tenderness that is
localized at the spinal cord, this is followed by radiating pain from the nerve
root of the infected area. The next phase is characterized by weakness of
voluntary muscles as well as bowel or bladder dysfunction. The final phase is
characterized by paralysis.

Soft tissue infections around
the spine include cervical and thoracic paraspinal lesions and lumbar psoas muscle abscesses. These are
often nonspecific in nature. In case of a paraspinal abscess the patient may
experience flank, abdominal pain or a limp. A psoas muscle abscess is
characterized by radiating pain to the hip or the thigh area.1

Pyogenic spinal infections may
present as pyogenic spondylodiscitis, vertebral osteomyelitis and epidural
abscess. Pyogenic
spondylitis typically involves two adjacent vertebrae and the intervening disk.
In the cervical spine, the pre-vertebral pharyngeal venous plexus and, in the
lumbar spine, the Batson’s paravertebral venous plexus may act as a potential
route of infection.2

Specific laboratory tests can be
useful in helping to diagnose a spinal infection. It may be beneficial to get
blood tests for acute-phase proteins, erythrocyte sedimentation rate (ESR) and
C-reactive protein (CRP) levels. Both ESR and CRP tests are often good
indicators as to whether any inflammation is present in the body (the higher
the level, the more likely it is that inflammation is present). These tests
alone however, are limited, and other diagnostic tools are usually required.
Identification of the organism is essential, and this can be accomplished through
computed tomography-guided biopsy sampling of the vertebra or disc space. Blood
cultures, preferably taken during a fever spike, can also help identify the
pathogen involved in the spinal infection.1

The imaging tools used for
diagnosis mainly include CT scans, X-Rays and MRI, MRI with Gd enhancement is a
useful tool.1

This study mainly focuses on understanding
spinal infections in relation to the respective spinal regions, the
neurological deficits caused and the various management strategies.

 

 

 

 

 

 

CLINICAL MATERIALS AND METHODS:

An
observational, cross-sectional study was conducted at Sancheti Institute for
Orthopaedics and Rehabilitation, Pune whereby all patients diagnosed with
Spinal Infections were included. Records of these patients attending the OPD
were obtained regularly and the relevant information was studied. Medical
records and diagnostic reports were reviewed to gather clinical information and
data. Patients who were diagnosed clinically as well as on the basis of radiographs
with spinal infections along with positive culture on pathology examination were
included. Data was collected over a period of 10 months (January, 2017 – October,
2017) from 30 male patients and 23 female patients diagnosed with spinal
infection including – Infective spondylodiscitis (pyogenic-klebsiella peumoniae,
tubercular, perivertebral, paraspinal, posas soft tissue abscess), pott’s spine
and post-operative spondylodiscitis. The average age of women was 50 years and
the average age of men was 52 years. Inclusion
criteria for the review were illness compatible with vertebral infection and
evidence of spinal involvement on MRIs. The MRI findings to define the
infection were bone marrow oedema, reduction in disc height, spinal cord
changes and/or paravertebral collections. Patients with tuberculosis were also
included.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RESULTS:

 

 

1)
Sites of Involvement (Spinal regions) –

 

The segment involved in patients diagnosed with spinal
infections was the cervical spine in 4 patients, the thoracic spine in 23
patients and the lumbar spine in 34 patients. In 7 patients multiple discs were
involved and all the levels were considered.

 

                        

        

 

 

Fig. 1 – INVOLVEMENT OF SPINAL REGIONS

 

 

                 

 

 

 

           

 

Fig. 1 A – REPRESENTATION
OF TUBERCULOUS SPINAL INFECTION AT THE CERVICAL SPINAL REGION

 

 

 

 

    

    

 Fig. 1 B – REPRESENTATION OF SPINAL INFECTION
AT THE THORACIC SPINAL REGION

 

 

 

 

 

 

 

 

Fig. 1 C –
REPRESENTATION OF SPINAL INFECTION AT THE LUMBAR SPINAL REGION

2) Vertebral levels affected

The location of the lesions (Spinal infections) were widely
distributed throughout the vertebral column, with greater incidences of
occurrence at the lower end of thoracic spine (T8 – T9) and
the highest incidence of occurrence at the L3 – L4 level.

 

 

 

 

Fig. 2 – VERTEBRAL LEVELS AFFECTED

 

 

 

 

 

 

 

 

 

 

 

3) Classification
of patients according to the causative organism –

In the sample population
diagnosed with spinal infections, considered for the study, 23 cases were
observed as tuberculous, 15 as pyogenic and 14 as inconclusive i.e. biopsy did
not reveal any organism. The x-axis represents the type of spinal infection
based on the causative organism and the y-axis represents the number of cases
respectively.

 

  

 

Fig. 3 – CLASSIFICATION
OF PATIENTS ACCORDING TO THE CAUSATIVE ORGANISM

 

 

 

 

 

4) Incidence of
spinal infections according to the gender –

The sample population diagnosed
with spinal infections included 30 males i.e. 57 % of the total sample
population and 23 females i.e. 43% over a period of 10 months visiting the OPD of
the institute

           

Fig. 4 – DISTRIBUTION OF SPINAL
INFECTIONS ACCORDING TO THE GENDER

 

 

 

 

 

 

 

 

 

 

5) Classification of
patients according to age –

The
sample size comprised of patients from the age of 16 years to 93 years old. In
the graph below, age of the patients is categorized and plotted on the X-axis
and the no. of patients in that age category is plotted on the Y-axis. The
graph shows that maximum number of patients i.e. 9, diagnosed with spinal
infections fall in the age category of 65 – 69 years.

 

 

Fig.
5 – CATEGORIZATION OF PATIENTS ACCORDING TO AGE

 

 

 

 

 

 

 

6) Vertebral levels corresponding
to soft tissue abscess –

Out
of the 53 patients, 5 patients also presented with associated paraspinal soft
tissues abscess at different spinal levels. The x-axis represents the number of
patients and the y-axis represents the corresponding levels of spinal abscess
in these patients.

 

          

 

Fig.
6 – VERTEBRAL LEVELS OF SOFT TISSUE ABSCESS

 

 

 

 

 

 

 

7)
Neurological involvement in patients with spinal infections –

Out
of the 53 patients diagnosed with spinal infections, 11 patients, that comprise
of 20% of the patients presented with neurological involvement such as
myelopathy, lower limb radiculopathy bowel and bladder involvement, neurological
deficit, paraplegia, spasticity and weakness.

 

         

 

Fig.
7 – NEUROLOGICAL INVOLVEMENT IN PATIENTS WITH SPINAL INFECTIONS

 

 

 

 

 

 

8)
Interventions used in the management of spinal infections –

Interventions
used in the management of spinal infections included immediate and prompt
surgery (36 cases), required and scheduled surgery at a later date (9 cases) as
well as antimicrobial therapy (8 cases), based on the level and complexity of
the cases respectively. The x-axis represents the interventions used in the
management of the spinal infections in patients and the y-axis represents the
number of patients in whom those interventions were used.

 

      

 

Fig.
8 – INTERVENTIONS USED IN THE MANAGEMENT OF SPINAL INFECTIONS

 

 

 

 

DISCUSSION:

Spinal
infections have a high rate of prevalence in patients. The age group most
affected by spinal infections in the sample population was 65 – 69 years.  Pyogenic spondylodiscitis represent 2-4% of
all cases of osteomyelitis.3 Spondylodiscitis is one the major consequence
of hematogenous osteomyelitis in patients over the age of 50 years. 4, 5
In the sample population considered in this study, 56 % of patients were over
the age of 50 years (Fig. 4) and the mean age of males was 52 and that of
females was 50. Literature suggested that, the most effective diagnostic test
for early detection of spondylodiscitis is MRI with a 93-96% of sensitivity and
92.5 -97% of specificity respectively. 6,7,8

Fig. 9 – MRI of
the spine demonstrating a classic appearance of a thoracic non tuberculous
spinal infection.

Spinal
infections were found to occur at all the spinal regions viz. cervical,
thoracic and lumbar regions with a major predilection for the lumbar region (34
cases) as compared to the cervical (4 cases) and thoracic (23 cases) among the
sample studied. While within the lumbar region, the most affected vertebral
level was L3-L4.

It
was observed that, 20% of the sample population had neurological involvement including
myelopathy, lower limb radiculopathy bowel and bladder involvement,
neurological deficit, paraplegia, spasticity and weakness.  

Infections
spread to the spine via three routes i.e. arterial, by direct external
inoculation and through other infected tissues. The haematogenous route is the
most common pathway for the spread of infection, by directly coming in contact
with the spinal column.6

It
was observed that most of the patients had spontaneous spondylodiscitis as
against post-operative discitis. The causative organisms of spondylodiscitis include
bacterial, fungal, mycobacterial and parasitic. Staphylococcus aureus is found to be the most common causative
factor of spondylodiscitis.9, 10, 11

Spondylodiscitis
was also associated with corresponding paraspinal soft tissue abscess in patients
within the sample population. Literature suggests that, spondylodiscitis is
associated with corresponding epidural abscesses at all three spinal levels
i.e. cervical region (90%), dorsal region (33.3%) and the lumbar region (23.6%).12

It
was observed that, of the sample population, 44% were tuberculous, 30% were
pyogenic and 26% were inconclusive in nature i.e. biopsy did not reveal any
particular organism. Tuberculous spinal infection account for about 2% of all
cases of tuberculosis and is caused by Mycobacterium
tuberculosis in the bone tissue of the vertebral column through the
haematogenous route.13 Pyogenic spinal infections comprise of a wide
range of individual representations. They have a prevalence rate of 0.2 – 2
cases per 100,000 per year.14 Pyogenic spinal infections are
classified based on the pattern of extension which are identified on an MRI and
DWI as – i) epidural / paraspinal abscess with spondylodiscitis ii) epidural /
paraspinal abscess with facet joint infection iii) epidural / paraspinal
abscess without concomitant spondylodiscitis or facet joint infection and iv) intradural
abscess (subdural abscess, purulent meningitis and spinal cord abscess).15

Management
of spinal infections is a crucial aspect in determining the prognosis of the
condition and the quality of life of the patient after the diagnosis. 68% of
patients from the sample population received surgical intervention, 17%
required surgery at a later point in time and 15% received antimicrobial
therapy. “The key principles of effective management of spinal infections are
antibiotic therapy, fixation of the respective spinal segment to preserve or
restore the spinal structure and stability; and debridement and decompression
of the spinal canal in the presence of neurological deficits or epidural
abscesses.” 16 In case of tuberculous spinal infection, specific
tuberculostatic therapy must be administered. In patients with no indication of
surgery, or requirement of surgery at a later point in time by opting for
conservative treatment, immobilization plays an important role to avoid the
risk of instability. The cervical spine is immobilized using a collar or a
halo-fixator while the thoracic or lumbar spine is stabilized using a
thoracolumbar brace.16 CT guided percutaneous drainage has proven to
be effective in patients with pyogenic spondylodiscitis and psoas abscess.16
The choice of surgical management of spinal infections is made based on the
degree of severity of the neurological involvement. “Indications for surgical
management include spinal instability due to extensive bone destruction, sever
kyphosis, intracanal spinal lesion, active tumors and in case of failure of the
conservative treatment.” 17, 18 In cervical spinal infections, an
anterior approach is recommended with appropriate debridement, decompression
(eventual corpectomy), and fusion with bone graft, associated with anterior
plate stabilization.  In the
thoracic spine, in the presence of epidural involvement without anterior disc
or bony destruction, a posterior approach with decompression and
instrumentation is usually the first option.16

 

CONCLUSION:

Spinal
infections is critical condition that requires prompt diagnosis and effective
management in order to improve long-term outcomes and avoid the risk of neurological
deficits. Diagnosis involves the use of MRI and management of spinal infections
includes effective conservative interventions at the earliest and timely
surgical management for an ideal outcome.

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