The Lumbar Spine in Sports Frederick A. Davis M.D. Southern California Permanente Group PM&R/Pain Management Symposium August 1, 2009
Outline • Overview • Anatomy and Biomechanics • Clinical Evaluation • History • Physical Examination • Specific Injuries • Sport Specific • Football • Gymnastics • Running • Golf • Baseball • Tennis • Bowling • Basketball
Lumbar Spine • Most injuries are relatively minor • Most injuries occur during practice • Most athletes are reluctant to document minor injuries • Most injuries are self limiting and resolve on their own…even without treatment! • So why do they need us????
The Problem • For the recreational athlete (weekend warrior to advanced amateur) • Their livelihood is usually obtained through means other than in the athletic arena • They may have this as such an integral part of their life, cessation or even reduction in activity may be extremely difficult to accept. • For those who have athletic ties that are intimately connected to their means of making a living.
The Problem • For the elite athlete • Their livelihood IS dependent on unencumbered physical performance • Lumbar spine injury is a frightening prospect. • Excellent functional outcome from treatment to be able to continue at the same level of performance is essential. • In either operative or non-operative treatment it is important to understand that the athlete will continue to face the same physical stresses and dangers that were injurious in the first place.
Epidemiology • Cumulative lifetime prevalence of low back pain is almost 80% with almost 30% of athletes having acute back pain as it relates to sports (Dreisinger TE, 1996. Kelsey JL, 1980). • The type of injury varies with age; nearly 70% of lumbar spine injuries in adolescent athletes in whom forces are exerted on skeletally immature spines • Injury often occurs in the posterior elements and muscles • The majority of low-back injuries in adult athletes are related to muscle strain and discogenic disease (Micheli LJ, 1995).
Epidemiology • 4790 athletes medical records studied over a 10 year period and 17 intercollegiate varsity sports with injury rate of 7 per 100 participants (Keene, JS. 1989). • Injury rates were higher in both gymnastics and football. • Only 6% of these injuries occurred during competition. • 80% occurred during practice • 14 % during pre-season conditioning • Injuries divided into 3 categories • Acute (most common) • Overuse • Pre-existing conditions
Epidemiology • U.S. Air Force Academy injury statistics, collected during a 1-year period, indicate that 9% of all athletic injuries are related to the spine. • Another study looked at 1000 injuries from one professional football team and found that 6% were related to the spine (Ryan, AJ. 1965). • Musculoskeletal injuries sustained by collegiate wrestlers and female gymnasts and found a 2% and 13% injury rate of the thoracolumbar spine.
Epidemiology • Athletes who have long trunks and particularly inflexible lower extremities are more prone to lumbar spine injury (Fairbank JC, 1984). • Sports involving repetitive hyperextension, axial loading (and jumping), twisting, or direct contact carry higher risks of low-back injuries. • In Keene’s 1989 study, a little more than 50% of these injuries were acute in nature (Keene JS, 1989).
Epidemiology • Catastrophic spine injuries account for less than 1% of all sports injuries and usually involves the cervical spine.
Anatomy • Specific Anatomic Points • Vertebral bodies are particularly large and heavy compared to rest of spine • The pedicles of the lumbar spine are short and heavy, arising from the upper part of the vertebral body
Anatomy • Specific Anatomic Points • The lamina are shorter vertically than the bodies and causes a gap between the lamina at each level, which is bridged only by ligaments • The spinous processes are broader and stronger than those in the thoracic spine; they project in a dorsal direction with little caudadangulation
Anatomy • Specific Anatomic Points • The articulations in the lumbar spine are the same three-joint complex. • The joints are oriented in a more sagittal plane. This orientation allows the lumbar spine to have relatively more flexion and extension than its thoracic counterpart but significantly less rotation. • This joint alignment also allows for lateral flexion in the lumbar spine.
Anatomy • Specific Anatomic Points • The anterior longitudinal ligament is relatively thicker in the lumbar spine. • The ligamentumflavum is much stronger than its thoracic counterpart. This increased strength is in part due to the fact that it serves as a bridge between adjacent laminae where there is no bony overlapping.
Anatomy • Specific Anatomic Points • The facet joint capsules of the lumbar spine are thicker and stronger in the lumbar spine, as are the supraspinous and infraspinous ligaments. • The stability of the lumbar spine is related much more directly to the ligamentous structures than the thoracic spine because of the loss of stability added by the rib articulations and rib cage.
Anatomy • Specific Anatomic Points • The musculature of the lumbar spine is organized in the same pattern as that of the thoracic spine. • As one moves more caudally into the lumbar area, the muscles of the superficial groups tend to become larger and stronger. • The enveloping fascia in the lumbar spine is thicker and stronger than its thoracic counterpart.
Anatomy • Specific Anatomic Points • Intervertebral Disc • Two components • The Annulus (the outer, laminar fibrous container) • Nucleouspulposus (the inner, semifluid portion) • The disks make up approximately one fourth of the height of the entire spinal column. • Moving from cephalad to caudad, the disks become thicker when measured from one vertebral end plate to the next. • The thoracic disks are heart-shaped compared with the more oval form seen in the lumbar spine.
Anatomy • The nucleus pulposus • Occupies a concentric position within the confines of the anulus. Its major function is that of a shock absorber. • The nucleus pulposus exhibits viscoelastic properties under applied pressure, responding with elastic rebound. • There is no definite structural interface between the nucleus and the anulus. The two tissues blend imperceptibly.
Anatomy • Specific Anatomic Points • The blood supply and nutrition of the intervertebral disk is achieved primarily by diffusion from the adjacent vertebral end plates. • The annulus is penetrated by capillaries for only a few millimeters. • The normal disk tissue has a high rate of metabolic turnover. • The disk itself has no direct inervation. Sensory fibers are abundant, however, in the adjacent longitudinal ligaments.
Biomechanics • Flexion • Requires an anterior compression of the intervertebral disk, along with a gliding separation of the articular facets . • Limited by the posterior ligament complex and the dorsal musculature. • Extension • More limited motion, producing posterior compression of the disk along with gliding motion of the zygo-apophysealjoint. • Limited by the anterior longitudinal ligament as well as the ventral musculature. The lamina and spinous processes limit extension by direct opposition.
Biomechanics • Lateral flexion • Lateral compression of the intervertebral disk, along with a sliding separation of the facet joint on the convex side, whereas an overriding of this joint occurs on the concave side. • Limited by the intertransverse ligament as well as the extension of the ribs.
Biomechanics • Rotation • Related most directly to the thickness of the intervertebral disk. • Compression of the annulus fibrosus fibers. • Limited directly by the geometry of the facet joints. • Limits rotation by resistance to compression in the annulus.
Biomechanics • The center of gravity is anterior to the lumbar spinal column which places much of the resistive force on: • The erector spinae muscles • Lumbodorsalfascia • Gluteus maximus. • The instantaneous axis of rotation or the effective pivot point, is near the center of the disc in normal lordosis and moves posterolaterally in extension (Pearcy MJ, 1988) • When combined together the annulus, disc, and posterior elements bear significant combinations of tensile stress and compressive and shear force, respectively whereas the posterior soft tissues bear considerable resistive stress.
Biomechanics • During flexion • The most strain is on the interspinous ligaments > capsular ligaments > ligamentumflavum. • During extension • The most strain is on the anterior longitudinal ligament • During lateral flexion • The most strain is on the contralateral transfers ligament > ligamentumflavum and capuslar ligaments • During rotation • The most strain is on the capsular ligaments of the facet joints (Panjabi, MM, 1982)
Biomechanics • Range of motion is due to a combination of the motion segments throughout the spine. • Flexion • 4 degrees in each of the upper thoracic motion segments • 6 degrees in the mid-thoracic region • 12 degrees in the lower thoracic region • Increases in the lumbar motion segments with a maximum of 20 degrees at the lumbosacral junction (White, AA and Panjabi, MM 1978)
Biomechanics • Lateral flexion • 6 degrees in the upper thoracic segments • 8-9 degrees in each of the lower thoracic segments. • 6 degrees in each of the lumbar segments • Exception is the lumbosacral segment which shows only 3 degrees. • Rotation • 9 degrees in the upper thoracic segments • 2 degrees in the lower lumbar segments • 5 degrees in the lumbosacral junction
Biomechanics • Range of motion is age dependent (McGill, SM 1999) • Decreases by 30% from youth to old age • Loss of range of motion occurs in flexion and lateral bending while axial rotation is maintained with increased coupled motion. • Range of motion has gender differences (Biering-Sorensen, F., 1984 and Moll JMH, et al, 1971) • Men have greater mobility in flexion and extension • Women have more mobility in lateral flexion
Biomechanics • Muscles • Flexors • Rectus abdominus, internal and external obliques, transverse abdominus and psoas • Extensors • Erector spinae, multifidus, and intertransversarii • Rotation and lateral bending • When right and left side flexor and extensor muscles contract asymmetrically lateral bending or twisting of the spine is produced (Andersson, GBJ, 1997).
Biomechanics • During the first 50-60 degrees of unloaded flexion range of motion occurs mainly in the lower lumbar motion segments (Carlsoo, 1961 and Farfan 1975) • Tilting the pelvis forward allows for more flexion. • When lifting and lowering a load this rhythm occurs simultaneously (Nelson, 1995). • Flexion is initiated by the abdominal muscles and the vertebral portion of the psoas muscle (Andersson, GBJ, 1997) • The posterior hip muscles control the forward tilting of the pelvis while flexion of the spine occurs (Carlsoo, 1961)
Biomechanics • The weight of the upper body is then controlled by the erector spinae muscles. • The quadratuslumborum superficial erector spinae muscles and deep are silent when upright. • As flexion increases the superficial > deep erector spinae become active. • At 90 degrees of flexion the quadratuslumborum and deep erector spinae are very active with less activity in the superficial erector spinae. • With full flexion (ie touching ones toes) the quadratuslumborum and deep erector spinae muscles are maximally active and the superficial erector spinae are silent (flexion-relaxation phenomenon).
Biomechanics • In forced flexion the superficial erector spinae muscles are activated. • As one goes from full flexion to being upright the muscle activity sequence reverses. • Gluteus maximus and the hamstrings activate early to rotate the pelvis to initiate the movement and then the erector spinae are activated until the motion is complete. • Compressive load of the spine caused by the muscle forces produced when lowering the trunk with a load or resistance can approach the spinal tolerance limits (Davis, KG, 1998)
Biomechanics • From neutral to hyperextension the extensor muscles initiate the motion and the abdominal muscles take over. • Forced extension (or extremes of extension) requires extensor activity. • During axial rotation the back and abdominal muscles are active on both sides of the spine to produce controlled movements. • The SI joints act mainly as shock absorbers to protect the intervertebral joints.
Biomechanics • During compression testing the fracture point of the vertebral body was reached before the intervertebral disc was damaged (Eie,N ,1966 and Ranu, HS 1990) • Forces ranged between 5000 and 8000 N. • The force of Earth's gravity on a human being with a mass of 70 kg is approximately 687 N. • A “yield point” was also reached prior to bony damage when the force was removed but it made the bond more susceptible to damage when reloaded. • Extrinsic support of the trunk muscles helps to stabilize and modify the loads.
Biomechanics • Sacral angle of inclincation • Normally the base of sacrum is pointing 30 degrees forward downward. • Tilting the pelvis backwards decreases the sacral angle and lumbar lordosis flattens. • Reduces the muscle energy exertion • Tilting the pelvis forward increases the sacral angle and lumbar lordosis increases and a compensatory increase in kyphosis occurs
Biomechanics • Walking at 4 different speeds (Cappozzo, 1984) • Compressive loads at the L3-4 motion segment ranged from 0.2 to 2.5 times body weight. • Loads maximized at toe-off • Loads increased linearly with increased walking speed. • Muscle action was focused in trunk extensors. • Forward flexion also increased the loads • Limiting arm swing increased joint loading
Biomechanics • Erector spinae muscles are intensely activated with lumbar hyperextension while prone and lessens with elbow support. • Pillow under the abdomen provides better spinal alignment to resist the forces. • Bent knee and straight knee sit ups produce comparable levels of psoas and abdominal activity and increase spinal loading. • Curl-ups or “crunches” minimize compressive loading in the lumbar spine (Axler, CT, 1997) • Unanchored feet, leg elevation or torso twisting do not significantly increase abdominal muscle acticity. • Isometric reverse curls with the buttocks off the table activate the internal and external obliques and the rectus abdominus and have less lumbar stress than a sit up.
Biomechanics • Intra-abdominal pressure (IAP) • The pressure created by coordinated contraction of the diaphram and abdominal and pelvic floor muscles. • Converts the abdomen into a rigid cylinder that greatly increases stability • Reduction in extensor moment varies from 10-40 percent. • Fine wire EMG shows that the transversusabdominus is the primary muscle for IAP generation. • Unexpected loading can increase extensor muscle activity by 70% (Marras WS, 1987). The shorter the warning the higher the increase in extensor muscle force (Lavender SA, 1989).
Biomechanics • External stabilization • Inconclusive evidence exists as to whether or not IAP is increased, if restriction of a motion segment helps reduce forces in the extensor muscles.
Clinical Evaluation • Goals • Resolution of problem • Return to play at the pre-injury level • Prevention of future injury
History • On the field/at the event • Mechanism of injury • Any loss or increase in neurologic function • What is a Stinger or burner? • Character of the pain • Sharp, stabbing, burning, tingling, throbbing • Location of the pain • Midline vs lateral • Does the pain radiate?
Physical Examination • On the field/at the event • If there is any question of a spinal column injury with neurologic symptoms, it is important to immobilize the athlete in the position in which he or she was found and not attempt to move the athlete. • No attempt should be made to remove equipment, such as a football helmet or part of the uniform. • The athlete and the provider are better served by over-immobilizing the injured athlete than by attempting to move him or her in a hurry to allow completion of the athletic event.
Physical Examination • On the field • ABC’s • Brief neurologic evaluation • Movement of fingers or toes where appropriate • Testing of sensation
Stinger or Burner • 2.2 brachial plexus injuries per 100 players per year • at the collegiate level approximately 50% of football players have sustained a stinger • estimated that 30% suffered their first injury while playing high school football
Stinger or Burner • Unilateral symptoms • Does NOT involve the legs • Look for associated problems (fractures, etc) • Check proper fit of equipment • Return to play when strength returns, tingling resolves and ROM normal.
History • Obtain a complete history (in the office) • Onset of the pain • Mechanism of injury • Any loss or increase in neurologic function • Character of the pain • Location of the pain • Duration frequency of the pain • Previous spine injuries • Factors that exacerbate or reduce pain