February 2007 News letter of the National Neurosciences Centre, Calcutta
THE FOCUS IN THIS ISSUE:
BACK PAIN
LUMBAR DISC DISEASE
His was almost a perfect life.
At the age of 26 he was the
area manager of not so small
a pharmaceutical concern,
he was still single, with his entire life before
him. Other than his profession his singular
passion was physical fitness. He was
happy- that he was able to squeeze a
minimum of half an hour at the gym into
his extremely busy day. That week was
particularly hectic. Having to visit the
distributors, pharmacies and physicians
across the area, meet deadlines, file
reports, his bike appeared to be his only
friend. It was a Saturday and he was
looking forwards to a relaxed morning on
Sunday. At the gym he had finished his
workout on the treadmill and was getting
ready to do abdominal exercises when it
happened! A cracking sensation somewhere
in the low back, and a severe shooting
pain, which racked his entire lower half. He
almost collapsed onto the floor. Any small
movement of his back was immediately
followed by a wave of electric shock like
pains that ran down his right leg from his
back. Easing himself onto the floor he
curled up into a position of comparative
comfort, and lay still, scared that the pain
would recur, and then he called for help.
The instructor at the gym came running
immediately; his friends gathered around
him, confusion prevailed. A few friends
asked him to stop acting, some gave
friendly medical opinions and advice; the
instructor assessed the situation quietly
and sent everyone back to their workouts.
He told him to relax, take a few deep
breaths and gave him a pain
CAUSES OF BACK PAIN
1. Traumatic
Sprain/ Strain
Fractures
2. Mechanical/ Degenerative/
Discogenic
Herniated Disc
Spondylosis (Facet Arthropathy
etc.)
Spondylolisthesis
Destructive Lens like
Tuberculosis
Metastatic Cancers, Myelomas
etc.
3. Inflammatory
Myositis
Fibromyalgia
Ankylosing Spondylitis/
Rheumatoid Arthritis
Sacroilitis
4. Congenital/ development
Spondylolysis
Tethered Cord
Occult Spina Bifida
5. Metabolic
Osteoporosis
Osteosclerosis
6. Others
Psychogenic
Postural
Referred Pain
Risk Factors for low back ache
Strongly Associated:
Prior history of back injury
Age, Job satisfaction/ emotional distress
Heavy or repetitive lifting/ physical work
Prolonged sitting or standing
Moderately Associated:
Vibration, smoking, obesity, height physical
fitness
Weakly Associated:
Gender Anthropometry, Lumbar mobility,
Trunk Strength
Most radiographic structural abnormalities
February 2007 News letter of the National Neurosciences Centre, Calcutta
killer. He then took him to the hospital.
X-rays were ordered a specialist was
consulted and there was the diagnosis:
a disc prolapse in the Lumbar Spine.
Questions filled his pain filled brain
"How did I, a fit young man get this?
What's going to happen to me? Will I
be bedridden for life?"
THE SPINE
The
spinal
column, which is
a bony structure,
serves essentially
two
purposes:
protection of the
spinal cord and
transmission of the body weight to the
lower limbs. The bony spine envelopes
the delicate spinal cord through its
entire length, placing the latter in a
long bony canal, which runs from the
nape of the neck till the natal cleft. This
protection is essential as the spinal
cord is one of the most delicate of
nature's creations and also one of the
most unforgiving. It is easily injured,
and once injured or affected, does not
give in easily to early recovery. The
spinal cord transmits nerves from the
brain to the rest of the body. These
nerves are given out at intervals,
coming out in pairs, on both sides. The
bony spinal column also aids in the
transmission of the weight of a person's
body to the lower limbs. For this it has
to be strong and also stable. The
strength of the spine is dependent on
the normality of its architecture and a
good calcium content of the bone. The
stability of the spine is maintained by
the same principle as that of a flag
pole. The bony spine represents the
pole, while the muscles on either side
of the spine, in front and behind,
represent the ropes that hold the pole
in position.
None of these work in isolation, in both
normal and pathological conditions. The
spine however, differs from the flag
pole in that it is not a straight rigid
structure, but one which is curved, as
well as segmented at regular intervals
by soft, well hydrated, cushion-like
shock absorbers called 'intervertebral
discs'. The segmentation of the spine
allows for movements of the body in
different directions. This movement is
limited to the neck (or cervical spine)
and the back (or lumbar spine). The
spine at the chest (or thoracic spine)
and the low back (or sacrum and
coccyx) is relatively immobile, not
allowing for movement. This differential
mobility causes the neck and the back
to be more affected by the stresses and
strains of daily living and therefore
leads
to
an
increased
risk
of
malfunction. The differential mobility
also has relevance in the event of
violent activity or jerks, especially
relevant in the setting of an accident.
Here the strain is more where the spine
is maximal mobile ad also at the
junction and immobile segment.
DISC PROLAPSE
The
most
common cause of
low back pain is a
disc prolapse or
what
is
colloquially called
a 'slipped disc’
Made up of a water saturated central
gel, called the 'nucleus pulposus', the
"disc" is contained within fibrous net
called the 'annulus fibrous'. The disc
absorbs the mechanical stresses and
strains of everyday life one bends,
stretches, jumps, turns etc. A disc
prolapse signifies the extrusion or
bulging of the gelatinous cent portion
of the disc material. As the disc bulges
February 2007 News letter of the National Neurosciences Centre, Calcutta
it
cause
inflammation
in
the
surrounding tissues including t nerves
that run adjacent. This is the stage I
back pain. When the disc prolapse
increases, there is a dirE contact
between the bulging and protruding
disc and t nerve that exits the spine
and goes to the leg. This stage II and
results in sciatic pain (or pain that runs
do one leg along the distribution of the
affected nerve).
When the disc fragment actually comes
out and enters the spinal canal (Stage
III), it compresses the nerve there
resulting in varying degrees of pain and
numbness in the foot or leg. When the
last happens suddenly, it can even
cause problems of passing urine or
weakness one foot. Chronic disc
disease leads to changes in the joints
of the involved spinal segments, as
they try adjust to the abnormal loads
and stress that occur with the different
phases of disc prolapse. Occasionally
the changes result in the joints
becoming loose, causing t segments to
move
relative
to
one
another.
Movement at the joints once again
causes pain as the pain sensitive joint
surfaces rub unnaturally against each
other.
Treatment for back pain and disc
disease should instituted at the
beginning of the problem. What many
us think is a muscle pull or strain is
actually the starting point of the disc
disease.
Correction
of
posture,
reduction of normal stress exercise help
in maintaining the status quo and
preventing progression of the problem.
Once static pain and chronic pain
starts, more rigorous and strict
changes in life style are necessary.
There should be no bending or lifting of
heavy weights, as these put the low
back under extreme vulnerability. The
back should be supported at all times
and should be given rest if there is
pain. Back strengthening exercise
should be performed on a regular basis.
The basic idea is to avoid progression
to the next stage when invasive
treatment options, including surgery
become essential. Surgical options,
minimal invasive or otherwise, give
excellent results when the procedure is
indicated. It should be performed only
when
there
is
continuation
of
symptoms in spite of conservative
measures, or when the patient starts
developing numbness or weakness, or
when pain is so severe that it is
incapaciting A word of caution here is
that
pain
is
very
subjective
phenomenon, the tolerance of pain is
varying fro one patient to another. Pain
is also influenced vastly by ones mental
make up and positive or negative
thinking.
These
individual
factors
should
necessarily be examined by the
treating physician when managing a
patient with back pain.
When deemed essential by both
patients and doctor, surgery for disc
disease is like magic as the pain just
disappears. Modern surgical procedures
are such that the patient can be made
to sit and stand within 2 days and can
get to work within 2 weeks.
Our friend the young man was given
conservative therapy including 48
hours of complete bed rest and pain
killers. He was then taught exercise for
his back, encouraged to swim, and
wear a Lumbosacral belt when riding
his bike. His smile is back on his face
and his back pain is a but a bad dream.
February 2007 News letter of the National Neurosciences Centre, Calcutta
ELECTRO DIAGNOSTIC (EDX)
STUDIES OF NERVES
NERVE CONDUCTION STUDIES (NCS)
Nerve conduction studies are carried
out by stimulating nerves electrically at
two or more sites and recording either
from muscles ( for motor nerves) or
nerve tract (for sensory nerves), the
conduction velocity, the latency and the
amplitude of the electrical response
(compound muscle active potential
CMAP). These are compared with
values defined in normal subjects. In
adults, the conduction velocity in the
upper limbs is normally between 50-70
m/sec and in the lower ' mbs 40-60
m/sec.
NCS
compliments
the
EMG
(Electromyography) examination and is
to be interpreted in conjunction with
clinical findings and with the results of
other laboratory studies. NCS studies
are very useful in determining the type
of neuropathy (demyelinating or axonal
type), and can distinguish between
mononeuropathy
multiplex
and
polyneuropathy.
NCS can also establish the diagnosis of
focal entrapment neuropathy like
Carpal Tunnel Syndrome or peroneal
neuropathy etc. The complimentary
roles of NCS and EMG are best
exemplified by a common clinical
problem: numbness and paresthesia of
the little finger with wasting of small
muscles of the hand may be due to an
intrinsic lesion of the spinal cord, C8/
T11 radiculopathy, brachial plexopathy
(lowertrunk or medial cord) or even an
ulnar nerve lesion. If sensory nerve
action potentials (SNAP) can be
recorded from the affected finger, the
pathology is most likely proximal to the
dorsal root ganglia i.e. A radiculopathy
or more central lesion. Absence of
SNAP suggests distal pathology. EMG
examination will help to differentiate
between plexus and individual nerve
lesions. Electro diagnostic studies thus
permit a definitive diagnosis and act as
a guide for specific management like
surgical decompression of nerve roots
in disc disease.
Dr Ashis Das
Cons. Neurophysician