Spinal disorders and the pain
associated with them account for a significant portion of disability at
work, with most complaints occurring in the lumbar region. Men are more
frequently affected. It is essentially a disease of the middle aged,
unless precipitated by trauma. L4/5 and L5/S1 disc account for 90% of the
cases, with each level affected about equally. L3/4 disc accounts for the
majority of the remaining herniations.
In the acute
presentation, symptoms often follow trauma or an injury to the disc
produced by a sudden spinal strain, such as lifting heavy weights. There
is acute low back pain, and, in the event of nerve root compression,
radiating pain, paresthesias, and motor weakness. Severe bilateral root
dysfunction may produce bowel and bladder incontinence and sexual
dysfunction. If the leg pain is not immediately experienced, it usually
appears over ensuing hours with associated paresthesias.
The leg pain is usually
worse and in dermatomal fashion. The back pain is thought to be secondary
to activation of the sinu-vertebral nerves to the annulus, which share a
central pathway with the nerve roots.
Chronic form is
characterized by chronic intermittent exacerbations of back ache, usually
without leg pain initially. The backache usually subsides with rest and
conservative measures, only to reoccur. The leg pain may be as well
localized as in the acute form.
The pain , unlike the pain
due to tumors, is usually subsides to some extent and with recumbency; the
pain is aggravated by increased activities, bending forwards, coughing,
sneezing, and straining at stools. Prolonged sitting increases the
intradiscal pressure and the pain.
On examination, the
patient presents with findings of axial pain and radiculopathy.
a) The paraspinal muscles
are often in spasm, particularly on the side opposite the leg pain,
and are tender to palpation. The patient leans away from the side of leg
pain with the hip and knee flexed in an effort to reduce the leg pain.
Spinal movements are
restricted due to pain.
Lateral bending towards
the side of leg pain closes the intervertebral foramen, compressing the
nerve root, and worsens the pain.
The straight leg raising
test and the crossed straight leg ( contra lateral leg) raising
stretches the sciatic nerve and L5 and S1 root pain get worse.
The reverse straight leg
(femoral stretch test) raising stretches the femoral nerve and reproduce
the leg pain in the distribution of the affected nerve root contributing
to the femoral nerve(L2,3 or 4).
examination may detect the motor, sensory, and reflex impairment (LMN
In the lumbar region, the
nerve roots exit through the intervertebral foramen caudal to their
corresponding vertebral pedicle (eg: the L5 root exits at L5/S1
intervertebral foramen); the majority of disc herniations, being
posterolateral, compress the root that exits at the intervertebral foramen
below the level of the involved disc (L5 root in L4/5/ posterolateral disc
herniation). In the less commoner lateral herniation, the root, that exits
the foramen at the level of the involved disc, is affected (L5 root in
L5/S1 lateral disc herniation).
L5 radiculopathy may
present with pain, and paresthesia/numbness along the posterolateral
aspect of the leg down to the great toe; weakness of extensor hallusis
longus and dorsiflexion may be noted.
S1 radiculopathy may
present with pain, and paresthesia/numbness along the posterior aspect of
the leg down to the lateral aspect of the heel and foot; weakness of ankle
plantar flexion may be detected. Ankle jerk may be absent.
L4 radiculopathy (as in
the posterolateral disc herniation at L3/4) may present with pain and
paresthesia/numbness along the anterolateral thigh and below the knee to
the medial aspect the leg and foot; weakness of quadriceps and knee
extension may be noted.
L3 radiculopathy the pain
and paresthesia may be localized over the anteromedial thigh and in L2 the
distribution is over the groin. Both L2 and L3 radiculopathies may cause
Large central discs may
cause bilateral symptoms or cauda equina syndrome. characterized by
asymmetric pain and paresthesias in the perineum and down the back or
front of the thighs and legs. Sensory disturbances may be limited to the
backs of the thighs, buttocks, anus, and perineum, so called saddle
anesthesia. paralysis of the bladder and rectum with associated
incontinence may occur if the compression is low and affects the sacral
MRI is the test of
choice for evaluation of disc disease. its multiplanar capabilities
make it suitable for visualizing far lateral disc herniations as well
as the paravertebral structures.
CT myelography still
is useful in patients with equivocal MRI studies and in those who are
unable to undergo MRI scanning.
initial management is nonoperative, unless the patient presents with
significant neurological deficit.
L5/S1 disc prolapse-
L3/4 disc prolapse-
The medical management
traditionally involves bed rest and analgesics and anti-inflammatory
drugs. Muscle relaxants help in some. TENS helps in about 20% of patients.
Indications for surgery
include failure of acceptable pain control by nonoperative measures,
progressive neurological deficit, and cauda equina syndrome.
The traditional approach
to lumbar discectomy is through posterior hemilaminotomy and foraminotomy,
either in prone position or 'knee-elbow' position, usually under general
anesthesia. Use of a microscope helps and has become a routine these days.
discectomy - wherein no bone is removed and the disc is approached by
excising the ligamentum flavum at the required level) is increasingly
employed with good results. The advantages in addition to minimal
disturbance to spines, are less post operative discomfort and less stay in
Whichever approach is
used, at least 10gms of disc material has to be removed for adequate pain
The 'so-called' minimally
invasive procedures, such as percutaneous chymopapain injection, automated
percutaneous discectomy, percutaneous laser discectomy, and endoscopic
discectomy are being advocated by some with varying results. Among these,
endoscopic discectomy has the potential to become the choice of treatment
Complications of surgery:
Bacterial discitis is a
most often considered complication, especially when there is recurrence of
pain and tender spines. It may warrant a corpectomy and fusion.
Dural injury must be
avoided; valsalva manoeuvre and primary closure of the dural rent at the
end of discectomy is preferable. Failure to close the rent will produce
pseudomeningocele and recurrence of symptoms. CSF fistula may result and
needs to be repaired.
scarring may present with recurrence and 'failed-back' syndrome. Treatment
Life threatening injury to
the major vessels, such as aorta, vena cava, and iliac vessels have been
reported. Bowel perforation may also occur.
Incidence of recurrent
disc herniation is thought to be about 10% and about 1/3rd of them in the
first year. They are treated the same way as at the original episode.
Fusion may be required in some patients, and recommended as a routine by
Approximately, 2/3 of the
patients with acute sciatica recover within 4 weeks; about 1/3 of them
report with recurrence.
The main advantage of
surgery is to accelerate the time to recovery. In most studies, there is a
definite advantage to surgery in the first postoperative year. In general,
patient selection is important. A motivated patient, with history,
physical findings, and diagnostic studies confirming nerve root
compression, can be expected to do well. 90% of the operated patients do
Patients with chronic
pain, and on prolonged use of narcotic analgesics, and patients with
psychological dysfunction orpending litigation for compensation should
alert the surgeon of possible poor outcome.