According to various research studies, about 80 percent of the population will suffer from at least one episode of acute back pain once in their lifetimes. Unfortunately, the statistics accumulate to great financial burdens among the medical system and the workforce in lost employee hours and decreased productivity.
Among the numerous types of issues which may cause symptoms known as extension related low
back pain, some of the most common include: spinal disc herniation and bulges;
degeneration of the spine; annular tears; ligament sprains; muscle strains,
particularly in the quadratus lumborum; osteoarthritis; rheumatoid and
ankylosing spondylitis; facet joint sprains; and stress fractures, pars defects
and spondylolisthesis.
However, those injuries which cause extension related low back pain can be due to an array of progressive disorders or pathologies along the lumbar spine, caused
by the tremendous amount of uncontrolled lumbar spine extensions among many
athletes from their specific sports or physical activity. These could essentially occur due to a postural, gradual onset of
repetitive trauma, most frequently associated with sports, for instance,
gymnastics.
Two particular demographic groups experience the most extension related
low back pain among the general population: the first group involves individuals who stand for extended periods of time, such as retailers,
military, security guards, etc. Standing for prolonged periods of time naturally forces the pelvis to begin changing into an anterior tilt angle, placing
compressive forces against the facet joints of the lumbar spine as these will
also begin to change towards a position of extension following the pelvic tilt;
and the second group involves athletes who participate in extension sports,
such as gymnastics, tennis, swimming, diving, football, volleyball, basketball,
track and field, and cricket fast bowlers, who've experienced sports injuries. This may be more apparent in sports
which include extension/rotation.
Pathomechanics
With normal extensions of the lower back, also referred to as backwards
bending, the facet joints come close to each other and compress, a natural
biomechanical movement. However, if the extension ranges are excessive, the
movements will forcefully compress the structures, damaging the cartilage
surfaces within the facet joints. Sports like gymnastics, tennis or football,
may all involve excessive and uncontrolled extensions of the body.
While unlikely, a bone stress response or a stress fracture could cause
an isolated extension injury. Instead, sudden, forced extension injuries
commonly damage pre-existing bone stress responses. In the same manner, if an
individual stands for extended periods of time and the pelvis migrates into an
anterior tilt, the facet joints are then placed under low load compression but
for prolonged periods of time.
With continued, uncontrolled loading, stress is then shifted from the
facet joint to the bone beneath it. This will initially manifest as a stress
reaction on the bone. The stress on the bone may then develop into a stress
fracture if not properly corrected. This type of fracture is also referred to
as a pars defect, or spondylolysis.
Researchers
believed that stress fractures were due to a congenital defect which occurred
during an athlete’s teenage years. However, studies have now concluded that
this type of issue most likely develops through years of overuse into extension
positions, particularly among young athletes involved in the mentioned
extension sports. Furthermore, one-sided pars defects tend to occur more
commonly in sports that also involved a fundamental of rotation, such as tennis
serving or fast bowling in cricket.
Stress
fractures generally also affect its opposite side, leading to bilateral stress
fractures, where the stress is then transferred to the spinal disc in between
the affected levels. The shift of one vertebrae over another is most commonly
known as spondylolisthesis, ranging from mild to severe.
Spondylolisthesis
presents bilateral pars defects which may be the result of constant stress
against the bilateral pars in extension sports. This is believed to be an
independent pathology which develops in the early growth stages of an
individual as this pathology is frequently diagnosed among the ages of 9 to 14
years of age. If they experience symptoms in later years as a result of
participation in extension sports, the defects may have been present within the
individual from a young age but manifested asymptomatically. As a result of
quick growth spurts in teenagers and due to the increased amounts of training teenage
athletes are involved in, there’s a possibility that a dormant variety of
spondylolisthesis may present itself as an acute onset of extension related low
back pain in the athlete’s later teenage years.
Spondylolisthesis
is commonly found as L5 slips on the S1 vertebra of the spine and the condition
can be graded according to its degree of slippage: grade 1, up to 25 percent;
grade 2, from 25 to 50 percent; grade 3, from 50 to 75 percent; and grade 4; up
to 75 percent and over.
The progression of bone stress reactions tends to follow the following
continuum: first, facet joint irritation occurs; second, a pars
interarticularis stress response develops; third, stress fractures manifest to
the pars; fourth, a pars defect, or spondylolysis develops; and last,
congenital spondylolisthesis or as a result of activity, occurs due to
participation in extension sports.
A landmark publication related to spondylolysis and spondylolisthesis
was presented by Researchers and they classified these injuries as follows: type I: dysplastic, where congenitalabnormalities of the L5 vertebra or the upper sacrum allow anterior displacement
of L5 on the sacrum; type II: isthmic,
a lesion which occurs in the pars interarticularis. This can be sub-classified
as lytic, representing a fatigue fracture of the pars, with elongated but
intact pars, or as acute fractures; type
III: degenerative, secondary to long-standing intersegmental
instability with associated remodeling of the articular processes; type IV: traumatic, where acute
fractures occur in the vertebral arch other than the pars; and type V: pathological, due to generalized
or focal bone disease affecting the vertebral arch.
The vast majority of spondylolysis and spondylolisthesis injuries are of
the type II, isthmic variety. The above stages can be referred to as posterior
arch bone stress injuries, or PABSI.
Epidemiology
Spondylolysis develops along the pars interarticularis of the lumbar
spine. It’s most common at the level of the L5 vertebra, approximately occurring
in 85 to 90 percent of cases. It has a high asymptomatic prevalence in the
general population. However, particularly in young athletes but also in other
athletes, it is a common cause of chronic extension related low back pain. In young
athletes, the condition is often known as active spondylolysis.
Active spondylolysis is common in almost every sport. Sports like
gymnastics, diving and cricket, present a much higher risk of developing the
condition due to the extension and rotation nature of these sports. From an
active spondylolysis to a non-union type of spondylolisthesis, these have been
linked to a higher incidence of lumbar disc degeneration.
Through screening and imaging, early detection can help highlight the
development of these conditions during the bone stress phase and, if it is
detected and managed in time, the further complications can be avoided due to
the healing capacity of the pars interarticularis in its early stages.
Teenagers and young adults are more frequently diagnosed with PABSI, or
posterior arch bone stress injuries as a result of the rapid growth of the
spine through growth spurts, characterized by a delay in the motor control of
the muscle system during this time. Furthermore, it is believed that the neural
arch becomes stronger over time, explaining the low incidence of bone stress
reactions in middle aged athletes.
Spondylolysis is considered to occur the most among the young athletic
population than in the general population. Studies in gymnasts, tennis players,
weightlifting athletes, divers and wrestlers, all demonstrate a higher
incidence of spondylolysis compared with the general population of similar ages
Common Sports Causing PABSI
Tennis
The well-known tennis serve actually creates excessive extension and
rotation forces which may be a contributing factor for injury. Also, a forehand
shot may produce high levels of rotation/extension. The more traditional
forehand shot involves increased amounts of weight or load which then shifts
through the legs into the torso and arms. A more favored forehand shot now
involves facing the ball and generating the force of the shot using hip
rotation and lumbar spine extension. This action does increase the speed of the
ball but it places more extension and compressive loads on the spine, which can
potentially lead to an increased degree of stress against the bones and other
structures of the body.
Golf
A golfing tee shot is believed to be one of the most probable component
behind the development of injuries, as the follow-through of the shot involves
a considerable amount of spine rotation with some degree of spine extension.
Cricket
Fast bowlers in cricket are the most susceptible to injury. Complications
generally occur on the opposite side to the individual’s bowling arm. As the
front foot engages on the plant phase, the pelvis suddenly stops moving while
the spine and torso continue to move forward. When the particular bowling
action rotation is combined with extension, this may place large forces on the
posterior arch of the vertebrae. Over 50 percent of fast bowlers will
experience a pars stress fracture, with young players being the most
vulnerable. Cricket authorities have implemented training and competition
guidelines to prevent these injuries by limiting the number of bowls in training
or games.
Gymnastics/Dancers
Because gymnastics and dancing involves a considerable amount of
repetitive spine extension, especially backflips and arabesques, athletes who
participate in these may be highly prone to suffer from injury as well. It has
been suggested that almost all Olympic level gymnasts have experienced a pars
defect. Certain limits have been developed, regarding how many hours young
gymnasts can train to avoid the repetitive and constant loading of the spine.
Diving
Through diving, spine extension injuries occur among athletes, primarily
off the spring board and on water entry.
Contact Sports
As with contact sports such as the NFL, rugby and AFL, specific
fundamental skill sets are required to execute spine extensions under load,
resulting in injury.
Field Events
The more common field events to cause injury during field event include
the high jump followed by the javelin throw. Both of these sports create
enormous ranges of spine extension and under considerable load, these may
commonly lead to injury.
Clinical diagnosis of PABSI in athletes
Posterior arch bone stress complications may manifest as asymptomatic
injuries. Research indicates that these have been displayed among the general
population without experiencing symptoms of back pain. However, many
individuals usually report deep and usually unilateral, or one sided, symptoms
of back pain. Additionally, the pain may radiate into the region of the
buttocks. Extension movements or backward bending movements have demonstrated
to aggravate symptoms of back pain due to posterior arch bone stress injuries,
or PABSI. This is generally described as a gradual progression of pain or may
be initiated by one acute episode of back pain from an extension movement.
Upon clinical examination, individuals or athletes with PABSI report
pain which may be obtained with a one-leg extension/rotation test, known as the
Stork Test, which is conducted by standing on the leg of the affected side. In
addition, the patient will experience tenderness over the site of the fracture
as well as postural faults, such as excessive anterior tilt and/or pelvic
asymmetry.
The one-legged hyperextension test, best known as the Stork Test, has
been suggested to be pathognomonic, or specifically characteristic, for active
spondylolysis. A negative test was described to effectively exclude the
diagnosis of a bone stress type injury, thus making radiological investigations
unnecessary.
However, researchers examined the connection between the one-legged
hyperextension test and gold standard bone scintigraphy and MRI. They found
that the Stork Test was neither sensitive nor specific for active
spondylolysis. Moreover, it poorly predicted the presence of injury. Therefore,
a negative test cannot exclude active spondylolysis as a possible cause and a
high degree of suspicion for PABSI must be suspected in young athletes involved
in extension sports which describe symptoms of extension related low back pain
but are asymptomatic on the Stork test.
Researchers suggest that the poor relationship between imaging and the
one-legged test may be due to a variety of factors. The extension test would be
expected to transfer a considerable amount of extension force onto the lower
lumbar spine as well as placing significant pressure on the pars
interarticularis, stressing other areas of the lumbar spine, such as the facet
joints and the posterior lumbar discs. This may subsequently cause pain and the
development of other disorders, such as facet joint arthropathy and lumbar disc
disease.
According to studies, grade 1 spondylolisthesis tends to be asymptomatic
while grade 2 and other lesions tend to manifest alongside leg pain or without
leg pain. On examination, a palpable slip may be apparent.
Imaging
Not all individuals or athletes suffering from PABSI will show positive
characteristics or positive signs on testing. As a result, radiological visualization
is essential as a part of a proper diagnosis. The imaging modalities available
in the diagnosis of bone stress injuries include:
Conventional radiology, a type of test which
is not very sensitive but it is
highly specific. Its restrictions are partially due to the direction of the
pars defect. Spondylolisthesis can be viewed on a lateral film X-ray. If the
plain film appears normal for spondylolysis, then a bone scan, or SPECT, may be
required.
Scotty Dog Appearance
Pars Defect
Spondylolisthesis
Planar bone scintigraphy, or PBS, is highly
sensitive but not very specific. Single photon emission computed tomography, or
SPECT, improves sensitivity as
well as specificity of PBS than simple radiographic studies. Correlating studies
between PBS and conventional radiology have demonstrated that scintigraphy is
more sensitive. Individuals with positive SPECT scans should follow up with a
reverse gantry CT scan to assess if the lesion is active or old.
Computed tomography, or CT, scans are considered to be more sensitive than
conventional radiology and are believed to have a greater specificity than
SPECT. Regardless of the type of cross-sectional image utilized, CT scans
provide information on the condition of the defect, such as an acute fracture,
unconsolidated defect with geodes and sclerosis, pars in process of
consolidation or repair. The reverse gantry view can evaluate this condition
better. Repeated CT scans can be utilized to monitor the progress and healing
of a pars defect.
Magnetic resonance imaging, or MRI, is a technique which demonstrates distinct
changes in the signal at the level of the pars. This is identified as stress
reaction and can be categorized into five different degrees of activity. MRI
can be useful for evaluating components that stabilize isthmic lesions, such as
intervertebral disc, common anterior ligament, and associated lesions. The MRI,
or magnetic resonance imaging, is not as specific or sensitive as SPECT and CT
combination.
For that reason, the present gold standards of analysis for athletes with extension
related low back pain are: bone scintigraphy with single photon emission
computed tomography, or SPECT, if positive; and limited reverse-gantry axial
computed tomography.
There are several regulations for utilizing the formerly mentioned modalities to diagnose injuries, including
the intravenous injection of radioactive tracer and the young athlete’s
exposure to ionizing radiation. MRI has many benefits above bone
scintigraphy, belonging to the non-invasive nature of the imaging and the
absence of ionizing radiation. MRI changes in active spondylolysis involve bone
marrow edema and fracture.
Although, it is much more difficult to detect the changes of active
spondylolysis with MRI. Detecting pathologies through MRI depends largely on the perception
of conflicting differences of signals when compared with normal tissue.
Moreover, for active spondylolysis, this understanding involves a small area of
bone along the pars interarticularis, which is surrounded by various other
structures. Apart from stress fractures in other regions of the body, the small
area of the pars interarticularis could make the detection of these alterations
more challenging.
Computed tomography has the ability to differentiate between acute and
chronic fractures and this distinction may be an important incentive to
heal fractures. Even though MRI may be equivalent to computed tomography in
detecting fractures, its inability to determine the age of a fracture reduces its
usefulness. Accordingly, in subjects with pars interarticularis fractures
detected by MRI, it may still be necessary to perform thin computed tomography
slices to determine whether a fracture is acute or chronic, an essential element
in fracture resolution.
Chiropractic for Athletes with Back Pain
After an athlete has determined the cause of an athlete's extension related
low back pain, there are several treatments available to help them find relief
from their symptoms. Chiropractic care is a popular, alternative
treatment option available to correct many spinal complications. After careful
diagnosis of the root cause of an individual’s symptoms, a chiropractor will typically utilize a series of spinal adjustments and manual manipulations to
correct any misalignments of the spine, or subluxations, helping to eliminate
the irritation or inflammation of the structures surrounding the affected
region of the spine, reducing or eliminating the individual’s
painful symptoms.
In addition, a chiropractor may recommend a sequence of stretches and
exercises according to the individual’s injury, increase the individual’s strength,
flexibility and mobility as well as speed up the rehabilitation process. Chiropractic care is an effective, alternative
treatment option for many types of injuries or conditions, primarily focusing
on those surrounding the spine, to help restore an athlete’s original health
after experiencing complications which manifest as extension related low back pain.
By Dr. Alex Jimenez