A Literature Review surrounding the diagnosis and management of Spondylolysis and Spondylolisthesis in athletes.

Spondylolysis is a lesion caused by stress fractures at the pars interarticularis, while a spondylolisthesis is the anterior translation of a spondylolytic section, usually in the lumbar spine. Progressive in nature, both conditions can lead to short and long term problems if untreated. Affected individuals often ignore the warning signs until the condition has progressed to an advanced stage, making management and resolution challenging and time consuming. I will discuss the epidemiology and progression of pars lesions, how they specifically affect an athletic population and how the conditions are diagnosed and managed focusing on current and future concepts.

 

Lower back pain is a common complaint and affects 85-90% of the general population at some point during their lives and between 2-5% of people per year (Trainor & Wiesel, 2002). Although limited evidence exists, some age matched studies suggest a higher prevalence of back pain among athletes (Kujala, Taimela, Erkintalo, Salminen, & Kaprio, 1996). Beaty, (1999, cited by Trainor & Wiesel, 2002) suggests that 6-13% of all back injuries are sport related while d'Hemecourt, Gerbino & Micheli, (2000) reports 10-15% of adolescent athletes experience lower back pain during sport, indicating that sports related lower back pain is relatively common.

 

Spondylolysis affects approximately 6% of the general population (Fredrickson, Baker, McHolick, Yuan & Lubicky, 1984). This figure has been formulated through plain radiographic evidence however with better imaging techniques; a high incidence of spondylolysis has been suggested (Kalichman, Kim, Li, Guermazi, Berkin & Hunter, 2009 and Teplick, Laffey, Berman & Haskin, 1986). The majority of spondylolytic defects are reported to be asymptomatic with about 25% of the symptomatic cases presenting with an associated spondylolisthesis (Fredrickson et al, 1984).

 

Rossi & Dragoni, (2001), report a higher radiographic prevalence of spondylolysis (13.9%) and spondylolisthesis (6.5%) in an athletic population with lower back pain (4243), in contrary to Soler & Calderón, (2000), who report, through similar methods, a marginally higher spondylolysis (8.1%) and spondylolisthesis (2.5%) prevalence in a comparable athletic population without back pain (3152). The conclusions which can be drawn from both studies confirm that certain sport, artistic gymnastics (17%), throwing field events (17-26%) and wrestling (25%), have a significantly higher percentage of spondylolytic and spondylolisthetic lesions than other sports events. Symptomatic back pain seems to be an indicator of increased likelihood of a pars defect, with a higher prevalence in some sports being attributed to a hyperextension movement with axial loading. Both studies compared the prevalence of pars defects in male and female subjects. Rossi & Dragoni (2001) found a significantly greater ratio of men (4.5:1) with a spondylolysis compared to Soler & Calderón, (2000), who found a 1:1 ratio between men and women. The latter study had a significantly higher percentage of females with spondylolisthetic lesions which according to the literature is expected (Seitsalo, Osterman & Hyvarinen, 1991, cited by Soler & Calderón, 2000). Future research may further investigate the effects of specific female overtraining syndromes, like the female triad and how these relate spinal stress fractures. 

 

Rossi & Dragoni (2001) and Soler & Calderón, (2000), found L₅ the most commonly affected level (81% and 84% respectively). The incidence decreases through each of the levels, with almost no involvement at L₁ and S₁. Similarly most of the pars defects were reported to involve only one segment (95% and 96%) with the remaining lesions affecting two or more different segments. The majority of radiographically diagnosed spondylolytic defects have been reported to be bilateral (86% and 78%), indicating a stress fracture at the right and left pars interarticularis on a single segment (Rossi & Dragoni, 2001 and Soler & Calderón, 2000). This value may have a significant meaning when determining best treatment practice, as unilateral stress fractures tend to have a much higher union rate especially when early diagnosis and better imaging techniques are used.

 

Adolescent athletes with back pain have a significantly higher percentage of spondylolytic lesions (47%) when compared to an adult population (5%) (Micheli & Wood, 1995). This suggests that lower back pain could be due to a pars defect especially in adolescent athletes who participate in repetitive loading sports. There may also be a connection between spondylolytic lesions and the adolescent growth phase. Some literature suggests that children who participate in sport are at a higher risk of spondylolisthetic progression (Muschik, Hahnel, Robinson, Perka & Muschik, 1996). There seems to be no good evidence limiting sports participation in an adolescent population due to pars defects.

 

Early diagnosis is vital in effective management of spondylolytic and spondylolisthetic disorders. Contributing factors include increased lumbar lordosis and associated factors like, abdominal weakness and shortening in the iliopsoas, hamstrings and thoracolumbar fascia (d'Hemecourt et al., 2000). Participation in sports activities which involve hyperextension of the lumbar spine, repetitive spinal movements, a variety of high velocity spinal movements and axial loading (Gregory, Batt & Kerslake, 2005) are the main causes of pars defects. Pain is normally confined to the lumbar spine with occasional pain in the gluteal region and posterior thigh, often associated with muscle shortening as opposed to radiculopathy (McCleary & Congeni, 2007). Some individuals demonstrate an increased lumbar lordosis due to a larger sacro-horizontal angle which may predispose them to spondylolytic defects especially if involved in specific loading sports (Sward, Hellstrom, Jacobsson, & Peterson, 1989). In a higher grade spondylolisthetic defect, a step-off may be palpated and can be associated with point tenderness over the effected spinous process which is also evident in some cases of spondylolysis (Bono, 2004). Jackson, Wiltse & Cirincoine, (1976 cited by Bono, 2004) described the single leg hyperextension test which involves the individual standing on one leg and hyperextending the lumbar spine. The test is positive for a pars lesion if pain is reproduced on the standing leg side. No literature has reported on the reliability or validity of this test.

 

Plain radiographs are traditionally requested for individuals presenting with lower back pain that are involved in certain higher risk sports and a spondylolysis is suspected. The normal views consist of antero-posterior, lateral and oblique views; however a cone-down lateral radiograph produces a clearer image of the posterior bone structure at L₅/S₁ than a normal lateral view (Pennell, Maurer & Bonakdarpour, 1985). The oblique radiographs can be beneficial in detecting a defect in that plane but left and right images should be taken. According to the Meyerding (1932) scale, spondylolisthesis is graded on a lateral radiograph, with grade I indicating a slip <25%; grade II, 25-50%; grade III, 50-75%; and grade IV, 75-100% however grade IV spondylolisthesis rarely occur. Some controversy exists regarding the usefulness of plain radiographs. Kalichman, et al., (2009) found a significantly higher proportion (11.5%) of spondylolytic defects in an adult population with lower back pain, detected with computed tomography (CT) compared to plain radiographs. Similarly (Saifuddin, White, Tucker & Taylor, 1997) compared CT to oblique radiographs in 34 patients with 69 defects. Only 32% of the defects were detected on the radiographs, suggesting poor sensitivity especially in early stage spondylolysis compared to CT. Radiographic imaging may still be useful in identifying advanced defects. They are significantly cheaper than other imaging techniques and accessible, however radiographs should not be considered as a definitive diagnosis of spondylolysis.  

 

When plain radiographs reveal negative findings in patients with persistent symptoms a bone scan, CT, single-photon-emission computed tomography (SPECT) or magnetic resonance imaging (MRI) can be used to achieve a more reliable diagnosis. A bone scan or scintigraphy is an investigation method which detects areas of bone turnover or stress reaction, which can represent an impending stress fracture. Jackson, Wiltse, Dingeman & Hayes, (1981) investigated 37 young athletes using plain radiographs and bone scans. The results indicated that 19% of the young athletes showed signs of a stress reaction with no visible pars defect. Interestingly all seven stress reactions were unilateral involving only one segment. This may indicate that if a stress reaction is identified and managed early, progression to the more common bilateral spondylolytic lesion may be prevented.

 

Current literature suggests that SPECT is the most sensitive test to detect lesions at the pars interarticularis (Harvey, Richenberg, Saifuddin & Wolman, 1998). Like bone scans, SPECT has been shown to reveal pars lesions before the development of radiographic changes but has also been shown to be a more sensitive investigation than bone scans. Bellah, Summerville, Treves & Micheli, (1991) found radiotracer uptake using SPECT in 44% of an adolescent athletic population. Only 32 of those 71 subjects showed radiotracer uptake when using a bone scan. This allows for an earlier diagnosis of bone stress reaction. A useful consequence of SPECT is that it shows up active and inactive spondylolysis. An active spondylolysis indicates higher rates of bone turn over which Sys, Michielsen, Bracke, Martens & Verstreken, (2001) suggest has a much better healing capacity but could also explain painful symptoms associated with the healing process. Limitations with SPECT are high exposure to radiation and it is time consuming. Harvey et al., (1998) also remark on SPECT’s lack of sensitivity to differentiate between pathology.

 

Where SPECT and bone scans can pick up early stress reactions, CT may be the most sensitive tool in diagnosis of spondylolytic lesions. Congeni, McCulloch & Swanson, (1997), used CT to investigate the type of lesion and the injury course. 40 athletes with diagnosed spondylolysis lesions by SPECT then had a CT scan. 45% showed a chronic lesion which was managed symptomatically while 40% had an acute lesion with identified healing which was managed with a brace. The authors also question the use of SPECT as a fracture diagnosis tool as a 15% false positive was also found in the fracture diagnosis. SPECT and CT should be complementary to each other to fully understand the extent of the lesion.

 

MRI is another possible method of investigation. Diagnosis often relies on radiographs and CT, both of which are not reliable in early detection and bone scans or SPECT which although sensitive in early diagnosis have high exposure to radiation and are time consuming. Yamane, Yoshida & Mimatsu, (1993), have used MRI to shown a hypointense area on T₁ weighted images before the appearance of a spondylolytic lesion. However Kujala, Kinnunen, Helenius, Orava, Taavitsainen & Karaharju, (1999) found that bone scan was more sensitive than MRI at identifying pars interarticularis stress reaction. The future of imaging especially with regard to pars stress lesions seems to indicate that MRI is becoming more popular. It currently has a high negative prediction value (Saifuddin & Burnett, 1997) and as the cuts get thinner the positive prediction value will rise. It also has the added advantage of less radiation exposure and is currently quite accessible.

 

Imaging protocol seems to follow a similar format. Initially patients receive anteroposterior, lateral and oblique radiographs followed by SPECT.  If SPECT shows diffuse uptake, they are normally treated as a stress reaction. Those showing focal uptake receive a CT scan to further define the anatomy however MRI may be considered over SPECT where patients have had pain for more than six weeks.

 

Young athletes involved in sports and activities which predispose them to pars interarticularis stress injuries need to be carefully observed. Athletes and young athletes especially, may ignore painful symptoms in the pursuit of athletic success. Early diagnosis of pars interarticularis stress reactions is especially important in achieving optimal recovery and prevention of disability later in life. Sairyo, Katoh, Sasa, Yasui, Goel, Vadapalli, Masuda, Biyani & Ebraheim, (2005) found that in 13 athletes with unilateral spondylolysis; diagnosed by CT, 6 had early stage spondylolysis with no contralateral complications while the 7 athletes who has progressive or terminal stage unilateral spondylolysis showed signs of contralateral involvement. This indicates that if unmanaged, a unilateral lesion will likely progress to a bilateral lesion. Unilateral stress reactions are fairly common (Jackson, et al, 1981); however unilateral spondylolysis only occur in about 10% of spondylolysis lesions, the majority being bilateral (Rossi & Dragoni, 2001). This suggests that once a unilateral stress reaction becomes a stress fracture, it progresses quickly to a bilateral stress fracture in the majority of cases.  Gregory et al., (2005) speculate that unilateral stress reactions progress to incomplete fracture before becoming complete fractures. Once a unilateral stress fracture has become complete, the contralateral side almost always becomes involved creating a bilateral spondylolysis. This is possibility due to the instability in the vertebral ring which stresses the contralateral pars interarticularis. Future research may investigate the effects pars lesions have on the surrounding structures and how this translates if the integrity of the vertebral ring is affected.

 

The progression of spondylolisthesis was investigated by Muschik et al., (1996). They found a mean displacement of approximately 10% over a period of 4.8 years. 86 athletes were investigated where 38% showed an increased displacement, 42% showed no progression and 9% showed a decreased in displacement. All the athletes continued to participate in competitive sport over the entire period without any symptoms suggesting asymptomatic adolescents with spondylolysis or spondylolisthesis should not be limited from participating in sport. Ikata, Miyake, Katoh, Morita & Murase, (1996) considered the progression from spondylolysis to spondylolisthesis and concludes that younger athletes are more likely to have a slip. This poses the question whether end plate disruption is a result or the cause of spondylolisthetic changes but could also indicate the possibility to predict future further progression. 

 

Common forms of non-operative management for spondylolysis normally consist of a period of rest or restricted activity and can also include physiotherapy modalities, immobilisation and electrotherapy. The main aim of the treatment is to relieve lower back pain by off loading the area with the stress reaction or stabilizing a fracture with or without fibrous union. Whether a stress reaction or spondylolysis almost all authors suggest a period of rest from the aggravating activity. Jackson et al, (1981) found that adolescent athletes with unilateral pars stress reaction diagnosed by bone scan made a full recovery and return to sport in an average of 7.3 months by limiting the aggravating activities and rest. All the follow-up investigations appeared normal indicating excellent recovery can be achieved with early intervention.

 

A stress reaction identified with a bone scan or SPECT but no radiographic evidence of a stress fracture should be treated with activity restriction to pain free limits and anti-lordotic bracing for 2-3 months to allow the stress reaction to heal fully (Bell, Ehrlich & Zaleske, 1988). A conditioning programme should be undertaken before returning to full sport. Optimal results would include bony union prior to return to sporting activity. Sairyo et al., (2005) examined 13 young athletes (14.8 years) for unilateral spondylolysis using CT and MRI. The individuals were divided into groups depending on the stage of unilateral spondylolysis detected. All individuals in the early stage spondylolysis group showed no signs of contralateral involvement while the subjects in the progressive and terminal stage spondylolysis group showed stress reactions at the contralateral pars interarticularis. All individuals underwent non-operative treatment and were investigated again between 3-6 months. All the early stage spondylolysis showed signs of healing while the later stage did not. Unilateral spondylolysis show a greater capacity to heal especially in the early stage however the evidence suggests that a unilateral lesion will quickly affect the contralateral side if left untreated. Early appropriate investigation and intervention is vital in achieving optimal healing.

 

Sys et al (2001) investigated the healing effect of active spondylolysis diagnosis in 34 competitive athletes with normal radiographs and positive bone scans using non-operative treatment. The conservative treatment used was an anti-lordotic brace for 23 hours a day for a period up to 6 months depending to the most recent bone scan. General mobility exercises were initiated when the individuals had no pain with activities of daily living. All unilateral lesions healed with excellent outcome. Over 50% of the bilateral spondylolysis achieved union while unilateral union was observed in the pseudo-bilateral group. The evidence seems to suggest that active stress fractures have the capacity to heal even in bilateral lesions, reiterating the importance of early diagnosis for optimal outcome; however non-bony union does not seem to affect the overall outcome with regarding to return to sport. Miller, Congeni & Swanson, (2004) did a follow up over 11 years on early detection spondylolysis in young athletes using positive bone scans and negative radiographs. They found that none of the 32 individuals who completed the survey required surgery and only required rare medical or manipulative treatment for their backs. The initial treatment consisted of relative rest, a non-rigid lumbar brace and flexion-only trunk strengthening exercises over 8-12 weeks. Initially return to sport was allowed when the individuals were pain free at rest, in hyperextension and during the sporting activity using the brace.

 

Iwamoto, Takeda & Wakano, (2004) reports that 40 athletes, identified by radiograph, who had to discontinue sport due to pain caused by a defect in the pars interarticularis, 35 (87%), could return to original sporting level despite bony non-union within an average of  5.4 months. The treatment consisted of rest and anti-lordotic bracing. El Rassi, Takemitsu, Woratanarat & Shah, (2005), investigated 57 adolescent soccer players with lumbar spondylolysis diagnosed with radiographs. They investigated results of individuals who stopped sport with or without bracing and those who continued playing with and without bracing. The groups who limited their sporting activity with and without bracing had a significantly better outcome than the latter two groups. Bracing alone did not seem to achieve optimal results unlike sport cessation alone which did have excellent results. This indicates that stopping sporting activities for period of time should allow the participant to return to previous sports level yet also questions the benefit of bracing.

 

O'Sullivan, Twomey & Allison, (1997) investigated the use of specific stabilizing exercise in managing pain associated with radiographically diagnosis spondylolysis and spondylolisthesis. 44 patients were divided into 2 groups, 1 which participated in specific contraction of the deep abdominal muscles and co-contraction with multifidus while the other group followed a protocol outlined by their doctor. The result suggest significant decrease in the study groups pain and increased functional level after 3 months up to 30 months compared to the control group whose treatment consisted of medication, massage and other pain relieving modalities. This study involves the general population but the results could be extrapolated to include an active population. Future research could investigate the results of early preventative strategies and how these compare to current studies.

 

Surgical treatment for spondylolysis normally occurs if non-operative management has been unsuccessful and the individual is still in a significant amount of pain which is limiting activities of daily living, which may or may not include sporting activities. If a spondylolisthesis is present, surgical intervention is undertaken if neurological symptoms are present, the slip is progressive or the individual has a grade III defined by the Meyerding scale. Discussion around the specific methods and controversies in the surgical management of this condition are outside the scope of this discussion. Surgical management can consist of a posterolateral fusion or a direct repair of the defect. Direct repair seems to be less popular than a fusion; however there is insufficient evidence of individual improvement compared to fusion (Bono, 2004). Debnath, Freeman, Gregory, de la Harpe, Kerslake & Webb, (2003) investigated the outcome of two different fusion techniques. Of the 22 athletes who underwent the surgical treatment 18 returned to previous sporting activities in an average of 7 months. There is a limited guideline for return to sport after a fusion but most surgeons seem to suggest full return is possible.

 

Spondylolysis and spondylolisthesis are conditions which if left untreated can cause athletes discomfort and potential disability. A clear understanding of the epidemiology and the disorder progression is vital in efficient and effective diagnosis and management. A clearly defined protocol will help to identify early disorders before they progress and better manage symptomatic individuals.

 

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