Spondylolysis and spondylolisthesis
in swimmers

 

A.F. MAVROGENIS [1], C.K. KYRIAKOPOULOS [1],
E.A. MITSIOKAPA [2], G.S. SAPKAS [1], P.J. PAPAGELOPOULOS [1]
[1]First Department of Orthopaedics, Athens University Medical School, Athens, Greece,
[2]Department of Physical Medicine and Rehabilitation, Thriassion Hospital, Elefsis, Greece

 

ABSTRACT
Swimming has a positive effect on the musculoskeletal and the cardiovascular system. However, highly intensive training and competitive swimming may lead to overuse injuries, the most common being low back pain. Spondylolysis is mainly reported in sports such as football, weightlifting, wrestling, diving, throwing, rowing, ballet dancing, rhythmic and artistic gymnastics, and swimming. The prevalence of low back pain and spondylolysis is greater in "front style" breaststroke swimmers, that involves repeating hyperextension and flexion movements of the lumbar spine. Computed tomography is the more accurate diagnostic imaging examination with high specificity in the identification of pars defects, and very useful in staging the lesion. Treatment options include close observation of the athlete, bracing (rigid or non-rigid) and, less commonly, surgical intervention. Treatment goals in the athletes should include minimizing time out from sports and minimizing bed rest, since atrophy may rapidly occur. In the majority of cases, clinical improvement is expected in 4-6 weeks and return to sport can be anticipated in 4 to 7 months, as soon as the athlete is sufficiently rehabilitated and can fully participate without symptoms.

Key words: spondylolysis, spondylolisthesis, swimming, rehabilitation.

INTRODUCTION
Swimming is an often recommended physical therapy for orthopedic patients, with a positive effect on the musculoskeletal and the cardiovascular system. It is a popular sport among athletic and non-athletic population. Experimental studies on rats have shown that swimming has a positive effect on bone growth and development, and an increase in subepiphyseal cancellous bone[1,2]. However, there are many pathologic conditions associated with swimming, presented particularly in highly intensive training and competitive swimmers. These are asthma, conjunctivitis, folliculitis, otitis externa, and overuse injuries of the spine, shoulder, knee, elbow and ankle[3,4]. Swimmers often start their careers during childhood, with intense training and participations at many meetings throughout the season. Highly intensive training and competitive swimming may lead to overuse injuries, the most common being low back pain[5].
The incidence of spondylolysis in the general population is reported between 2-7%[6,7]. Spondylolysis and spondylolisthesis are common causes of back pain in athletes, most often diagnosed in children between 5 and 10 years old. At this age, the immature spine is placed at repeated axial loading in hyperextension and hyperflexion from intense training and competitive athletic activities, many times resulting in overuse injuries, or a stress fracture of the pars interarticularis (figure 1)[5,8-14]. In some athletic activities, the incidence of spondylolysis is reported to be rising up to 50%[15], and, although there are studies reporting spondylolysis to be frequent in swimmers[9,16], detailed work-up is not yet confined. Spondylolysis is mainly reported in sports such as football, weightlifting, wrestling, diving, throwing, rowing, ballet dancing, and rhythmic and artistic gymnastics[5,7,12]. The isthmic grade I lesions at the L5-S1 segment are the more common and important in athletes[9].
The prevalence of spondylolysis and spondylolisthesis is greater in men athletes. In adolescence, no male prevalence is noticed, and girls appear to have the same injury rate as boys in the same sports, but with different mechanisms of injury[17].

 

1.
Figure 1. Schematic presentation of isthmic spondylolysis and spondylolisthesis grade Ι of the fifth lumbar vertebra.

BIOMECHANICS - RISK FACTORS
Many authors have stated the importance of biomechanical factors in the causative relationship between sports and spondylolysis-spondylolisthesis[18]. Biomechanical analyses and clinical studies in sports with great prevalence of spondylolysis[5,7,10-14] have attributed this condition to repeated stress loading of the lumbar spine in hyperextension, hyperflexion, rotation and torsion, resulting in spinal overuse injury, or fracture of the pars interarticularis. These studies are supporting the fact that physical forces and movements are major factors in the production of low back pain, spondylolysis and spondylolisthesis.
Risk factors predisposing the swimming athlete to lumbar spine injury include the abrupt and sudden increases in swimming volume and training frequency and intensity, the incorrectly and unsupervised performed weight training and dry land exercises, the swimming style, the use of special swimming training devices, the improper technique and unsuitable equipment, and the inappropriate athletes' physical fitness. Inflexibility of the lumbar spine and laxity of the back and abdominal, the hamstrings and the hip flexors muscles may be the causes of chronic low back pain and spondylolysis[19].
Currently swimmers start practising at a very young age, with increasing swimming volume. Abrupt increases in work and training load may be one of the major factors causing stress fractures of the pars interarticularis[12].
Axial loading of the spine results in shear forces transmitted to the pars interarticularis[12]. The prevalence of low back pain and spondylolysis is greater in "front style" breaststroke swimmers[16,19]. There are two "front style" strokes with greater incidence of spondylolysis. The "butterfly" and the "wave style" breaststroke (figure 2)[16]. Both swimming strokes involve repeating hyperextension and flexion movements of the lumbar spine.
Special swimming training devices such as kicking boards, fins, pull-buoys, hand paddles and zoomers are currently used by swimmers. Although more body work-out is achieved, these devices are exposing the back into increased and repeated extension forces.
As well as in other sports, the swimmer's physical fitness has a great role in the overall performance of the athlete. In addition, athletes in a bad musculoskeletal fitness are more susceptible to injuries. Competitive swimming requires muscle stretching and back and abdominal muscle strengthening exercises to prevent overuse injuries of the lumbar spine.

2.
Figure 2. The prevalence of low back pain and spondylolysis is greater in "front style" breaststroke swimmers. Front style swimming involves repeating hyperextension and flexion movements of the lumbar spine.

CLINICAL PRESENTATION
Pain is the commonest presenting feature in adolescents and adults[20]. It is located in the lower back, occasionally radiating to the sacroiliac area and the buttocks unilaterally or bilaterally. In most cases, pain is related with activity and relieved by rest, and exacerbated by hyperextension and side flexion of the lumbar spine. In children, loss of back mobility and tight hamstrings, an unusual posture or abnormal gait noticed by the parents, may be the only symptoms[1].
A drop in the athlete's performance attributed to low back pain may also be the presenting feature requiring investigation and orthopedic evaluation[4,21].

3.
Figure 3. Typical radiographic findings of spondylolysis. Oblique radiographs show the typical "scottie dog" appearance and the radiolucency in the pars interarticularis defect areas with or without associated reactive sclerosis.

DIAGNOSTIC IMAGING
The diagnosis of pars interarticularis defects can be established by different imaging modalities that include plain radiographs (anteroposterior, lateral and 45° oblique), computed tomography, magnetic resonance imaging, bone scans and single photon emission computed tomography (SPECT).
Traditionally the evaluation of the orthopedic patient is initiated, and the diagnosis of lysis is made by standard radiographs. Although recent guidelines of the Royal College of Radiologist and World Health Organization are not routinely indicating plain X-rays in the clinical management of acute or chronic low back pain[22], these should be the first imaging studies performed in every athlete with spinal sports injury, especially in the young and adolescents where the prevalence of structural problems such as spondylolysis and spondylolisthesis is higher[23]. The typical plain radiographic findings are the "scottie dog" appearance and the radiolucency in the pars interarticularis defect areas with or without associated reactive sclerosis (figure 3)[9]. However, many authors have reported a high rate of inaccuracy and less sensitivity and specificity of standard radiographs compared to other imaging methods[20,24-28].
Computed tomography has been reported to be the more accurate diagnostic imaging examination[24,29], with high specificity in the identification of pars defects, and very useful in staging the lesion[30]. Osseous imagination is far better with computed tomography than with magnetic resonance imaging, especially in acute spine injury with low back pain[26]. Acute fractures in various stages of healing, chronic, non-healed fractures, or no obvious fractures of the pars interarticularis are best seen with CT.
Magnetic resonance imaging is a useful imaging modality in the evaluation of the spinal cord, the intervertebral disc spaces, the nerve roots and the neural foramina. It should be interpreted when computed tomography is non-diagnostic[23,28,31]. However, in the identification of spondylolysis with magnetic resonance imaging, a high associated false positive rate has been reported[32].
Bone scan is a useful imaging modality showing increase radionuclide uptake in stress reaction pars interarticularis defect areas. It allows earlier diagnosis because of its high sensitivity to alterations of bone metabolic activity, thus permitting early treating and early healing of the disease without progressing to roentgenographically detectable defects[9,33].
Bone scan is reported to have a 15% false positive rate when compared to SPECT[26]. This may represent early stages of spondylolysis not detected with plain radiographs or computed tomography scans[28]. SPECT has been found to be more accurate and much more sensitive in the depiction of alterations in bone metabolism and in the identification of pars lesions compared to planar bone scan[9,26,27,33]. It can also differentiate between acute and chronic lesions, and between spondylolysis and spondylolisthesis[33]. It is reported however that, as pars defects become chronic, SPECT views tend to appear normal even though healing has not yet occurred[33].

TREATMENT
At the approach of the athlete with low back pain the physician must depend on the duration of symptoms, and the associated clinical (i.e. neurologic deficits) and radiographic findings. A thorough history, physical and imaging examinations are usually productive in determining the diagnosis. Treatment options may include close observation of the athlete, bracing (rigid or non-rigid) and, less commonly, surgical intervention[24,26,30,34,35]. Treatment goals in the athletes, in comparison to the non-athletic population should include minimizing time out from sports and minimizing bed rest, since atrophy may rapidly occur[34].
Treatment usually depends on the radiographic staging of the pars lesion. In early stage lesions (minimal or no separation, sclerosis without separation, or only stress reaction), patients are initially treated with rest, anti-inflammatory medication, bracing, amount of time out of the sport, and no activity participation except normal routine daily activities[24,30]. Bracing is used if symptoms persist after 2-3 weeks of rest[35-39]. Generally, rigid bracing limits spinal motion more than soft bracing[37], and the decision on the type of the brace depends on the severity of the lesion and the amount of motion restriction is required. In these stage lesions conservative treatment is continued for 2-3 months, which is the minimum of time required to achieve bone healing and the patient to become fully asymptomatic[28]. At this time training could be reinitiated with a graded rehabilitation and training program that include spinal stabilization muscle strengthening exercises (back and abdominal muscles, and hip extensors), and aerobic work-out with an emphasis on swimming-specific activities and techniques. Radiographic follow-up is usually not recommended in athletes responding to treatment, with asymptomatic spondylolysis without spondylolisthesis. Prolonged bed rest should be avoided. Early strengthening exercises should include the Williams flexion exercises and the McKenzie extension exercises. Athletes with spondylolysis and spondylolisthesis should initially be limited to flexion exercises[35,39].
In athletes with more advanced pars interarticularis lesions (significant separation, dense sclerotic margins, and high stage spondylolisthesis) treatment is similar, but bone healing is probably not to be expected[24,28,30,35,38,39]. Sport and vigorous daily activity restriction is the primary treatment plan, but only until the athlete is pain-free, at which time is referred to a gradually increasing dynamic rehabilitation program, with spinal muscle strengthening exercises dependent on specific swimming style and the athlete's individual characteristics[35,39]. Bracing is used as above[36,37]. Relapse of pain during treatment, or refractory to treatment patients should be reevaluated and further clinically and radiographically assessed for any alterations in the disease process. Radiographic follow-up is usually recommended in athletes with spondylolisthesis (especially young and adolescents), in athletes with progressive pars lesions, and in athletes in whom a rapid return to sport is desired[7,26,33].

RETURN TO SPORT
In the majority of cases clinical improvement is expected in 4-6 weeks and return to sport can be expected in 4 to 7 months, as soon as the athlete is sufficiently rehabilitated and can fully participate without symptoms[20,38]. Preventive rehabilitation measures should include proper training technique, gradual increase of training frequency and intensity (particularly in front style, butterfly stroke swimmers), and suitable dry land strengthening exercises of the back, abdominal and hips musculature[3,26,29,35,39,40-42].

CONCLUSION
Low back pain in young and adolescents swimming athletes is a clinical manifestation of many diseases that should not be ignored but fully evaluated. With an increasing number of skeletally immature athletes competing at increasingly more demanding sport levels, an associated increase in the number of structural problems such as spondylolysis and spondylolisthesis may be seen. Stress induced defects in the pars interarticularis in young and adolescents athletes may be the source of considerably long disability, particularly if undiagnosed and untreated. Knowledge of the sport-specific biomechanics, the risk factors, and the clinical features of the disease, provide early and precise diagnosis, and appropriate treatment.

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