Spondylolysis. A skeletal investigation of two population groups

Prevalence and Characteristics of Lumbar Spondylolysis in White and Black Patients

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To the best of our knowledge, the prevalence of lumbar spondylolysis in white and black populations has never been studied using computed tomography (CT). The purpose of this study was to examine and compare the prevalence and characteristics of lumbar spondylolysis in white and black patients.

METHODS

This study is a cross sectional study. Patients aged 20-79 who underwent abdominal and pelvic CT for trauma screening in the New York City area and whose race was classified as "white" and "black" on the questionnaire were recruited to the study. A total of 1200 white patients (600 women, 600 men) and 1200 black patients (600 women, 600 men) were included for the analysis. The presence of lumbar spondylolysis, level, unilateral/bilateral, and the presence of spondylolisthesis at lumbar spondylolysis level were evaluated using CT.

RESULTS

The prevalence of lumbar spondylolysis was 3.0% (n = 36) for white patients and .8% (n = 10) for black patients, with 3.3% (n = 20) and 1.0% (n = 6) for white and black females, respectively; and 2.7% (n = 16) and .7% (n = 4) for white and black males, respectively. The prevalence of lumbar spondylolysis was significantly higher in white patients compared with that in black patients (P < .0001). Lumbar spondylolysis was at L5 in 44/46 patients (95.7%) and bilateral in 41/46 patients (89.1%). Spondylolisthesis at lumbar spondylolysis level was found in 40/46 patients (87.0%).

CONCLUSIONS

The prevalence of lumbar spondylolysis was 3.0% for white patients and .8% for black patients. The prevalence of lumbar spondylolysis was significantly higher in white patients compared with that in black patients.

Is Increased Kicking Leg Iliopsoas Muscle Tightness a Predictive Factor for Developing Spondylolysis in Adolescent Male Soccer Players?

OBJECTIVE

To identify predictive risk factors of lumbar stress (LS) fracture developing from an asymptomatic stress reaction of the pedicle among adolescent male soccer players.

DESIGN

Prospective cohort study.

SETTING

Amateur Japanese adolescent male soccer team.

PARTICIPANTS

Japanese adolescent male soccer players (n = 195) aged 12 to 13 years.

ASSESSMENT OF RISK FACTORS INDEPENDENT VARIABLES

Height, body weight, body mass index, muscle tightness of both lower extremities (iliopsoas, hamstrings, and quadriceps), lumbar bone mineral content, developmental age, and lumbar lordosis angle were measured as baseline measurements.

MAIN OUTCOME MEASURES DEPENDENT VARIABLE

Players who were diagnosed with an asymptomatic stress reaction of the lumbar spine pedicle at baseline were followed; extension-based lumbar pain was defined 1 year after the baseline. The players were assigned to the LS fracture or control (CON) group at follow-up.

RESULTS

At baseline, 40 boys were diagnosed with an asymptomatic stress reaction of the lumbar spine pedicle. The difference in muscle tightness between the kicking leg and supporting leg was significantly different (P = 0.012) between the LS (n = 16) and CON (n = 22) groups. Increase in iliopsoas muscle tightness in the kicking leg was a predictive risk factor of developing extension-based lumbar pain after adjusting for developmental age and body mass index (odds ratio, 1.54; 95% confidence interval, 1.05-2.27).

CONCLUSIONS

Development of extension-based lumbar pain from an asymptomatic stress reaction of the pedicle among adolescent male soccer players was associated with increased iliopsoas muscle tightness of the kicking leg relative to that of the supporting leg.

Upper Lumbar Bone Stress Injuries in Elite Cricketers

OBJECTIVE

Describe the proportion of upper lumbar bone stress injuries (LBSI; T12-L3) relative to all LBSI, and the clinical presentation and diagnosis of upper LBSI in elite cricketers.

DESIGN

Case series.

SETTING

Professional domestic and international cricket teams over a 9-year period.

PARTICIPANTS

Elite Australian cricketers.

INDEPENDENT VARIABLES

Symptomatic upper LBSI diagnosed based on clinical findings and medical imaging.

MAIN OUTCOME MEASURES

Prevalence, injury history, and clinical management.

RESULTS

Twenty-four pace bowlers (22 male and 2 female) sustained 39 cases of upper LBSI (T12:2, L1:3, L2:20, L3:14). Upper lumbar vertebrae were involved in 41% (95% CI 31-51) of all LBSI in this cohort. Twenty-seven (69%, 54-81) cases had an injury that occurred only on the side contralateral to the bowling arm. Ipsilateral injuries tended to occur secondary to a contralateral nonunited defect. In all 7 cases with known radiology follow-up that had a contralateral then ipsilateral LBSI, the contralateral injury did not achieve bony union before the onset of the ipsilateral LBSI. For stress fractures with imaging follow-up, those who achieved bony union took longer to return to bowling training [median 152 days (IQR 117-188)], compared to those who achieved partial or no union [median 68 days (IQR 46-115)].

CONCLUSIONS

Upper LBSI in elite cricketers occurs in approximately 2 out of 5 cases of LBSI. Clinicians should allow sufficient time for upper LBSI to resolve and unite (if a fracture) because cases that returned to bowling training earlier were less likely to achieve bony union, and those that failed to unite commonly went on to have a recurrent LBSI.

LEVEL OF EVIDENCE

Therapy/prognosis/diagnosis level 2b.

Lumbar spondylolysis - Current concepts review

Lumbar pars interarticularis (PI) injury or spondylolysis occurs only in humans. This represents a stress fracture of the PI. Excessive loading in repetitive hyperextension is a significant risk factor and occurs most commonly at L5 followed by L4. It is bilateral in 80% of symptomatic cases but can be unilateral defect as well which runs a more benign course. Symptoms of low back pain relating to this lesion are more common in young athletes involved in trunk twisting sports. Like other stress fractures, the pain may come on abruptly or more insidiously over time and only related to certain activities. The pathologic progression starts with a stress reaction in the pars, progressing to an incomplete stress fracture, and then a complete pars fracture. Diagnosis is dependent on clinical examination and radiological imaging studies (plain radiography, computed tomography (CT) scans and magnetic resonance imaging (MRI) scans). Treatment is dependent on symptoms as well as radiographic stage of the lesion. Conservative management is the mainstay of treating early lesions. A comprehensive rehabilitation program incorporates core spinal stabilization exercises. Athletes should not return to sports until pain free. Professional sporting individuals are at increased risk of failure of resolution of symptoms that may require early surgical repair of the PI defect. Modified Buck's technique & pedicle screw-hook constructs for direct repair has a high success rate in patients who have persistent low back pain. Minimally invasive lumbar pars defect repair has given similar successful outcome with added advantage of minimizing muscle injury, preserving the adjacent joint and reduced hospital stay. Functional outcome is evaluated using the Visual Analogue Scale (VAS) for back pain, Oswestry Disability Index (ODI) and 36-Item Short-Form Health Survey (SF-36). Preoperative ODI and SF-36 physical component scores (PCS) are significant predictor of a good functional outcome.

Spondylolysis in the past: A case study of hunter-gatherers from Southern Patagonia

Spondylolysis is a fracture of the pars interarticularis, the portion of the neural arch that lies between the superior articular facets and the inferior articular facets. Clinical evidence has suggested repetitive trauma to be the most probable cause, even though morphological weakness of the vertebra is probably also involved. Prevalence is between 3% and 8% in modern populations, while in archaeological samples it varies from 0% to 71.4%. Considering that very little data about this condition is available in past populations from the southern extreme of South America, the aim of this paper is to analyze the spondylolysis in a human skeletal sample from Southern Patagonia and, at the same time, to explore the prevalence of spondylolysis in archaeological contexts around the world to gain a better understanding of the results presented here. The Southern Patagonian skeletal series analyzed here showed a prevalence of 20%, with lower prevalence in the pre contact sample (11.1%) than in the contact period (23.1%). Skeletons from the Salesian Mission "Nuestra Señora de La Candelaria" showed a higher prevalence (25%) than the sample of skeletal remains recovered from outside the mission (20%), suggesting that changes in lifestyle of hunter-gatherers during contact could be implicated in the development of spondylolysis in this sample. A worldwide survey displays a wide range of prevalence figures in American and Asian samples and low diversity between African and European populations. Hunter-gatherers from Southern Patagonia showed similar values to those observed in other American samples.

Surgical Management of 3-Level Lumbar Spondylolyses

Three-level lumbar spondylolyses are extremely rare. So far, only 11 cases were reported in the literature. Treatment of multilevel spondylolyses has not been consistent. Conservative treatment is commonly considered first in most patients, but those who remain symptomatic may benefit from operative treatment. We report here 3 cases of 3-level lumbar spondylolyses that were treated successfully with direct isthmic repair in 2 cases and a combined surgery of isthmic repair and interbody fusion in 1 case. Our clinical results indicated that direct defect repair using the screw-hook technique is a simple and safe procedure for the motion segment with normal disc. If the involved disc shows degenerative change, fusion surgery should be consideredSurgical treatment of multilevel spondylolyses varies between fusion, direct isthmic repair, and combined management associating 2 procedures at different levels. The success of management of the 3 patients with 3-level spondylolyses depends on the choice of appropriate treatment for every patient.

Chiropractic management of mechanical low back pain secondary to multiple-level lumbar spondylolysis with spondylolisthesis in a United States Marine Corps veteran: a case report

OBJECTIVE

This case report describes the evaluation and conservative management of mechanical low back pain secondary to multiple-level lumbar spondylolysis with spondylolisthesis in a United States Marine Corps veteran within a Veterans Affairs Medical Center chiropractic clinic.

CLINICAL FEATURES

The 43-year-old patient had a 20-year history of mechanical back pain secondary to an injury sustained during active military duty. He had intermittent radiation of numbness and tingling involving the right lower extremity distal to the knee. Radiographs of the lumbosacral region demonstrated a grade I spondylolisthesis of L3 in relation to L4 and a grade II spondylolisthesis of L4 in relation to L5 secondary to bilateral pars interarticularis defects. There was marked narrowing of the L4-5 disk space with associated subchondral sclerosis.

INTERVENTION AND OUTCOME

A course of conservative management consisting of 10 treatments including lumbar flexion/distraction and activity modification was provided over an 8-week period. Despite the long-standing nature of the complaint and underlying multiple-level lumbar spondylolysis with spondylolisthesis, there was a 25% reduction in low back pain severity on the numeric rating scale and a 22% reduction in perceived disability related to low back pain on the Revised Oswestry Disability Questionnaire.

CONCLUSIONS

Conservative management is considered to be the standard of care for spondylolysis and should be explored in its various forms for symptomatic low back pain patients who present without neurologic deficits and with spondylolisthesis below grade III. The response to treatment for the veteran patient in this case suggests that lumbar flexion/distraction may serve as a safe and effective component of conservative management of mechanical low back pain for some patients with spondylolysis and spondylolisthesis.

Prevalence of spondylolysis and its relationship with low back pain in selected population

Background

To determine the prevalence of spondylolysis in a selected population and evaluate the association of spondylolysis with low back pain (LBP). Spondylolysis is widespread in the general population but the prevalence of spondylolysis and its relationship with LBP in the Korean population is controversial.

Methods

A sample of 855 participants (age, 20 to 86 years) from our medical center who underwent multidetector computed tomography (CT) imaging to assess abdominal and urological lesions were enrolled in this study. The occurrence of LBP requiring medication in the preceding 12 months was evaluated using a self-report questionnaire (a modified Nordic Low Back Pain Questionnaire). The presence of spondylolysis was characterized by CT imaging. Multiple logistic regression models were used to examine the association between spondylolysis and LBP, while adjusting for gender and age.

Results

Seventy-eight study subjects (9%) demonstrated spondylolysis on CT imaging. There was no significant difference between the age groups (p = 0.177). The p-value of gender was 0.033 but this was not significant due to the selected population bias. Three hundred eleven study subjects (36%) had back pain. There was a significant difference between gender (p = 0.001). No significant association was identified between spondylolysis and the occurrence of LBP.

Conclusions

The prevalence of LBP was 36.37% and the prevalence of lumbar spondylolysis in a selected population, who visited hospital for abdominal or urological lesions except LBP, was 9.12% based on CT imaging. Males demonstrated a similar presence of LBP to females but a significantly higher incidence of spondylolysis (p = 0.033). The prevalence of spondylolysis was not associated with the presence of LBP and age in adulthood.

Spina bifida: a diagnostic dilemma in paleopathology

This article provides information regarding the etiology, pathogenesis, and skeletal manifestation of spina bifida or spinal dysraphisms. On the basis of a review of the medical literature, it addresses discrepancies in documentation and interpretation of spina bifida in paleopathology. Furthermore, it offers suggestions for use of universal terminology and highlights the difficulties in the specific diagnosis of dysraphisms in skeletal remains. In addition, the necessity of examining the entire skeleton for abnormalities to distinguish simple delay/failure of fusion of the posterior neural arches from other occult spinal dysraphisms is emphasized, as it is the need for stratification of the sample by age and sex when reporting frequencies of sacral spina bifida occulta.

Incidence and etiology of lumbar spondylolysis: review of the literature

BACKGROUND

Lumbar spondylolysis is a defect of the pars interarticularis known to occur as a stress fracture. Its incidence varies considerably depending on ethnicity, sex, and sports activity. However, there are few literature reviews describing its incidence in different ethnic groups or in people who engage in different sports.

METHODS

We reviewed the most relevant articles on spondylolysis published in scientific journals. First, we focused on its incidence in various ethnic groups distributed by sex, the familial occurrence, and in patients with relevant diseases. Second, we focused on the incidence of spondylolysis in relation to the sports practiced by the patients. Although placing special emphasis on the incidence of lumbar spondylolysis in the general population in Japan, we also reviewed the Japanese and English literature to investigate its incidence among those who engage in different sports.

RESULTS

The incidence of lumbar spondylolysis in the general Japanese population was 5.9%. Most studies report that the incidence in higher in male subjects than in female subjects. We found that Japanese rugby and judo players were prone to suffer lumbar spondylolysis, at an incidence of about 20%. However, the incidence for Japanese professional soccer and baseball players was much higher, at 30%, which was more than five times the incidence in the general Japanese population.

CONCLUSIONS

The incidence of lumbar spondylolysis varies depending on ethnicity, sex, family history, relevant disease, and sports activity.

Sacral orientation and spondylolysis

STUDY DESIGN

A descriptive study (based on skeletal material) was designed to measure sacral anatomic orientation (SAO) in individuals with and without spondylolysis.

OBJECTIVE

To test whether a relationship between SAO and spondylolysis exists.

SUMMARY OF BACKGROUND DATA

Spondylolysis is a stress fracture in the pars interarticularis (mainly of L5). The natural history of the phenomenon has been debated for years with opinions divided, i.e., is it a developmental condition or a stress fracture phenomenon. There is some evidence to suggest that sacral orientation can be a "key player" in revealing the etiology of spondylolysis.

METHODS

The pelvis was anatomically reconstructed and SAO was measured as the angle created between the intersection of a line running parallel to the superior surface of the sacrum and a line running between the anterior superior iliac spine (ASIS) and the anterior-superior edge of the symphysis pubis (PUBIS).SAO was measured in 99 adult males with spondylolysis and 125 adult males without spondylolysis. The difference between the groups was tested using an unpaired t test.

RESULTS

Spondylolysis prevalence is significantly higher in African-Americans compared to European-Americans: 5.4% versus 2.04% in males (P < 0.001) and 2.31% versus 0.4%, P < 0.001 in females. SAO was significantly lower in the spondylolytic group (44.07 degrees +/- 11.46 degrees) compared to the control group (51.07 degrees +/- 8.46 degrees, P < 0.001).

CONCLUSION

A more horizontally oriented sacrum leads to direct impingement on L5 pars interarticularis by both L4 inferior articular facet superiorly and S1 superior articular facet inferiorly. Repetitive stress due to standing (daily activities) or sitting increases the "pincer effect" on this area, and eventually may lead to incomplete synostosis of the neural arch.

Incidence of lumbar spondylolysis in the general population in Japan based on multidetector computed tomography scans from two thousand subjects

STUDY DESIGN

Epidemiological analysis using CTs.

OBJECTIVE

To investigate the true incidence of lumbar spondylolysis in the general population in Japan.

SUMMARY OF BACKGROUND DATA

Although there have been several reports on the incidence of lumbar spondylolysis, they had some weakness. One of them concerns the subjects investigated, because the incidence of lumbar spondylolysis varies considerably, and some patients are asymptomatic. In addition, most of the past studies used plain radiograph films or skeletal investigation. Therefore, the past reported incidence may not correspond to that of the general population.

METHODS

We reviewed the computed tomography (CT) scans of 2000 subjects (age: 20-92 years) who had undergone abdominal and pelvic CT on a single multidetector CT scanner for reasons unrelated to low back pain. We reviewed them for spondylolysis, spondylolytic spondylolisthesis, and spina bifida occulta (SBO) in the lumbosacral region. The grade (I-IV) of spondylolisthesis was measured using midsagittal reconstructions.

RESULTS

Lumbar spondylolysis was found in 117 subjects (5.9%). Their male-female ratio was 2:1. Multiple-level spondylolysis was found in 5 subjects (0.3%). Among these 117 subjects, there were 124 vertebrae with spondylolysis. Of them, 112 (90.3%) corresponded to L5, and 26 (21.0%) had unilateral spondylolysis.SBO was found in 154 subjects. Of them, 25 had spondylolysis (16.2%), whereas, in 1846 subjects without SBO, 92 had spondylolysis (5.0%). The incidence of spondylolysis among the patients with SBO was significantly higher than that in subjects without SBO (Odd ratio was 3.7-fold).Of 124 vertebrae with spondylolysis, 75 (60.5%) showed low-grade (Meyerding grade I or II) spondylolisthesis, and no subject presented high-grade spondylolisthesis. Spondylolisthesis was found in 74.5% of the subjects with bilateral spondylolysis, and in 7.7% of those with unilateral spondylolysis.

CONCLUSION

The incidence of lumbar spondylolysis in the Japanese general population was 5.9% (males: 7.9%, females: 3.9%).

Multiple levels of lumbar spondylolysis - a case report -

We report here on an unusual case of multiple levels of asymmetric lumbar spondylolysis in a 19-year-old woman. The patient had severe low back pain of increasing intensity with lumbar instability, which was evident on the dynamic radiographs. MRI demonstrated the presence of abnormalities and the three dimensional CT scan revealed asymmetric complete spondylolysis at the left L2, L3 and L4 levels and the right L1, L2 and L3 levels. This case was treated surgically by posterior and posterolateral fusion at L2-3-4 with intersegmental fixation using pedicle screws and an auto iliac bone graft. The patient was relieved of her low back pain after the surgery.

Segmental wire fixation for lumbar spondylolysis associated with spina bifida occulta

INTRODUCTION

The effectiveness of segmental wire fixation technique in repairing lumbar spondylolysis has already been reported. However, whether the technique can be indicated for spondylolysis associated with spina bifida, which is occasionally found with spondylolysis, is not well known. In this study, the authors report the mid-term clinical outcome of the procedure performed in patients with symptomatic lumbar spondylolysis associated with spina bifida occulta.

MATERIALS AND METHODS

Among 20 patients with symptomatic lumbar spondylolysis who underwent segmental wire fixation between 1996 and 2001, four patients associated with spina bifida occulta were evaluated with an average of 32 months follow-up. Bony union at spondylolysis sites and spina bifida was evaluated using plain X-rays and computed tomography (CT) scans. Clinical symptoms were assessed using Japanese Orthopedic Association scores for back pain (JOA scores) and Henderson's evaluation of functional capacity.

RESULTS

The radiographic examinations of the latest follow-ups revealed the following results. Pars defect; in three cases with bilateral defect, one case healed bilaterally and two healed only unilaterally. One case with unilateral defect healed. Spina bifida; two cases showed bony union and two showed no union. Of the four patients operated, two were rated excellent with the remaining two good according to Henderson's evaluation. The recovery rate of JOA score was averaged at 69.7 +/- 23.5%. No serious complications were noted.

CONCLUSIONS

In four cases associated with lumbar spondylolysis and spina bifida, segmental wire fixation provided satisfactory clinical outcomes.

Isthmic spondylolisthesis in a nonambulatory patient: a case report

STUDY DESIGN

Case report.

OBJECTIVE

We present a case of a nonambulatory patient with an isthmic spondylolisthesis.

SUMMARY OF BACKGROUND DATA

Pars defects are thought to be due to repeated mechanical stress on the spine in individuals with bipedal posture. Epidemiologic and mechanical studies have supported the idea that repeated lumbar flexion and extension can lead to stress fractures of the pars interarticularis and subsequent spondylolisthesis. There are no documented cases of isolated pars defects in nonambulatory patients. We present a case report of an isolated isthmic spondylolisthesis in a patient who has never ambulated.

METHODS

Discussion of the patient's clinical and radiologic history with a brief review of the relevant background literature.

RESULTS

A pars interarticularis lesion was identified on plain radiographs in a 17-year-old girl with mixed spastic-athetoid cerebral palsy who never ambulated.

CONCLUSION

Although ambulatory individuals who engage in activities with repeated lumbar flexion have an increased risk of isthmic spondylolisthesis, this condition can occur in those who do not walk as well. This case illustrated that, although repetitive stress on an upright spine can increase an individual's propensity to develop a pars interarticularis defect, bipedal posture is not an absolute requirement for the development of this lesion.

The role of quadratus lumborum asymmetry in the occurrence of lesions in the lumbar vertebrae of cricket fast bowlers

In cricket fast bowlers an increased incidence of stress fractures or lesions in the L4 pars interarticularis is observed, which shows a strong statistical correlation with the presence of hypertrophy in the contralateral Quadratus Lumborum (QL) muscle. This study aims to find a physical explanation for this correlation. A mathematical model was used to estimate the forces and moments on the L3 and L4 vertebrae in six postures attained during fast bowling. These forces and moments were used in finite element models to estimate the stresses in the pars interarticularis. Two scenarios were examined per posture: symmetric QL muscles, and right QL muscle volume 30% enlarged. Influence of muscle activation was also investigated. QL asymmetry only correlates with significant stress increases when stress levels are relatively low. When stress levels are high, due to extreme posture or muscle activation, asymmetry only causes small stress changes, suggesting that asymmetry is not the cause of stress fractures in the pars. There are even indications that asymmetry might help to reduce stresses, but more detailed knowledge of the size and activation of the lumbar muscles is needed to confirm this.

Clinical outcome of symptomatic unilateral stress injuries of the lumbar pars interarticularis

STUDY DESIGN

A prospective case-series study.

OBJECTIVE

To evaluate the results of nonoperative and operative treatment of symptomatic unilateral lumbar pars stress injuries or spondylolysis.

SUMMARY OF BACKGROUND DATA

Most patients become asymptomatic following nonoperative treatment for unilateral lumbar pars stress injuries or spondylolysis. Surgery, however, is indicated when symptoms persist beyond a reasonable time affecting the quality of life in young patients, particularly the athletic population.

METHODS

We treated 42 patients (31 male, 11 female) with unilateral lumbar pars stress injuries or spondylolysis. Thirty-two patients were actively involved in sports at various levels. Patients with a positive stress reaction on single photon emission computerized tomography imaging underwent a strict protocol of activity restriction, bracing, and physical therapy for 6 months. At the end of 6 months, patients who remained symptomatic underwent a computed tomography (CT) scan to confirm the persistence of a spondylolysis. Eight patients subsequently underwent a direct repair of the defect using the modified Buck's Technique. Baseline Oswestry Disability Index (ODI) and Short-Form-36 (SF-36) scores were compared with 2-year ODI and SF-36 scores for all patients.

RESULTS

Eight of nine fast bowlers in cricket were right-handed. The spondylolytic defect appeared on the left side of their lumbar spine. In the nonoperated group, the mean pretreatment ODI was 36 (SD = 10.5), improving to 6.2 (SD = 8.2) at 2 years. In SF-36 scores, the mean score for physical component of health (PCS) improved from 30.7 (SD = 3.2) to 53.5 (SD = 6.5) (P < 0.001), and the mean score for the mental component of health (MCS) improved from 39 (SD = 4.1) and 56.5 (SD = 3.9) (P < 0.001) at 2 years. Twenty of 32 patients resumed their sporting career within 6 months of onset of treatment, and a further 4 of 32 patients returned to sports within 1 year. The 8 patients who remained symptomatic at 6 months underwent a unilateral modified Buck's repair. The most common level of repair was L5 (n = 5). One patient with spina bifida and a right-sided L5 pars defect remained symptomatic following direct repair. The mean preoperative ODI was 39.4 (SD = 3.6), improving to 6.4 (SD = 5.2) at the latest follow-up. The mean score of PCS (SF-36) improved from 29.6 (SD = 4.4) to 49.2 (SD = 6.2) (P < 0.001), and the mean score of MCS (SF-36) improved from 38.7 (SD = 1.9) to 54.5 (SD = 6.4) (P < 0.001).

CONCLUSIONS

The increased incidence of the unilateral lumbar pars stress injuries or frank defect on the contralateral side in a throwing sports, e.g., cricket (fast bowling), may be related to the hand dominance of the individual. Nonoperative treatment for patients with a unilateral lumbar pars stress injuries or spondylolysis resulted in a high rate of success, with 81% (34/42) of patients avoiding surgery. If symptoms persist beyond a reasonable period, i.e., 6 months, and reverse gantry CT scan confirms a nonhealing defect of the pars interarticularis, one may consider a unilateral direct repair of the defect with good functional outcome. Direct repair in patients with spina bifida at the same lumbar level as the unilateral defect may be complicated by nonunion.

Low-Grade Spondylolisthesis

Spondylolisthesis is an often painful condition affecting millions of people in North America with some ethnic variability. It is characterized by the displacement, usually anterior, of on vertebral body upon another. There are familial predispositions to having the lesion, and a family history of spondylolisthesis may raise one's clinical suspicion. Although the diagnosis is easily made on radiographic evaluation, the pathoetiology and appropriate treatment modality are not always as clear. In the absence of severe neurological symptoms or an unsafe component of instability, a trial of conservative management is reasonable and prudent. Nevertheless, surgical management is more efficacious for enduring symptomatic relief and restoration of physical function. Whereas assessment of postoperative radiographic results lends insight to surgical technique, the true barometer of treatment success is improvement in patient quality of life.

Lumbar facet anatomy changes in spondylolysis: a comparative skeletal study

Opinions differ as to the exact mechanism responsible for spondylolysis (SP) and whether individuals with specific morphological characteristics of the lumbar vertebral neural arch are predisposed to SP. The aim of our study was to reveal the association between SP and the architecture of lumbar articular facets and the inter-facet region.

METHODS

Using a Microscribe three-dimensional apparatus (Immersion Co., San Jose, CA, USA), length, width and depth of all articular facets and all inter-facet distances in the lumbar spine (L1-L5) were measured. From the Hamann-Todd Human Osteological Collection (Cleveland Museum of Natural History, OH, USA) 120 normal male skeletons with lumbar spines in the control group and 115 with bilateral SP at L5 were selected. Analysis of variance was employed to examine the differences between spondylolytic and normal spines.

RESULTS

Three profound differences between SP and the norm appeared: (1) in individuals with SP, the size and shape of L4's neural arch had significantly greater inter-facet widths, significantly shorter inter-facet heights and significantly shorter and narrower articular facets; (2) only in the L4 vertebra in individuals with SP was the inferior inter-facet width greater in size than the superior inter-facet width of the vertebra below (L5) (38.7 mm versus 40 mm); (3) in all lumbar vertebrae, the right inferior articular facets in individuals with SP were flatter compared to the control group.

CONCLUSIONS

Individuals with L4 "SP" characteristics are at a greater risk of developing fatigue fractures in the form of spondylolysis at L5.

Spondylolysis, spondylolisthesis, and lumbo-sacral morphology in a medieval English skeletal population

The prevalence of spondylolysis and spondylolisthesis was studied in an adult skeletal series from a rural English medieval archaeological site. Attempts were made to evaluate the association of three aspects of lumbo-sacral skeletal morphology (pelvic incidence (a measure of the anterior inclination of the sacral table), lumbar transverse process width, and the presence of lumbo-sacral spina bifida occulta) with spondylolysis and spondylolisthesis. Results indicated a high prevalence of spondylolysis compared with a modern reference population, but few cases of spondylolisthesis were identified. Analysis of prevalence with respect to age suggests that in the study population, pars interarticularis defects generally formed late in the growth period or early in adult life. The study group showed a high mean pelvic incidence compared with modern Western Europeans, indicating a more steeply inclined sacral table, which may have elevated the risk of developing pars interarticularis defects. However, no statistically valid association could be demonstrated between the presence/absence of spondylolysis and pelvic incidence in the study material. There was no evidence for a link between lumbar transverse process index or lumbo-sacral spina bifida occulta and spondylolysis/spondylolisthesis. It is concluded that the potential role of lumbo-sacral morphology, as well as of activity regimes, should be considered when interpreting spondylolysis in paleopathological studies. If the frequency of spondylolysis is to some extent an indicator of past activity regimes, it may reflect lifestyle in younger individuals rather than in mature adults. Further work investigating the link between spondylolysis and lumbo-sacral morphological variables in premodern populations would be of value.

Preoperative evaluation of adult isthmic spondylolisthesis with diskography

Fourteen consecutive patients with a diagnosis of isthmic spondylolisthesis (grade I and II) underwent provocative lumbar diskography (L2-S1) to evaluate the disk adjacent to the spondylolisthesis. Seven (50%) of 14 patients had concordant pain at the disk above the slip and 2 patients had no pain at the slip level. Surgical treatment included anteroposterior fusion of the slip level and any adjacent concordant levels. Clinical results included 3 excellent, 7 good, 2 fair, and 1 poor outcome. This data supports the hypothesis that the disk adjacent to an isthmic slip is predisposed to symptomatic degeneration in the adult patient with axial pain. It does not prove that a fusion is indicated or that clinical outcomes would be improved with this approach.

The Course of the Nerve Root in the Neural Foramen and Its Relationship with Foraminal Entrapment or Impingement in Adult Patients with Lumbar Isthmic Spondylolisthesis and Radicular Pain

The purpose of this study was to demonstrate the course of a nerve root in the neural foramen and its relationship with foraminal entrapment or impingement in 19 adult patients with isthmic spondylolisthesis and radicular pain. Myelo-computed tomography and magnetic resonance imaging showed that the course of the nerve root was normal (ie, medial and then inferior, along the pedicle) in 10 patients and was deviated posteriorly in 9 patients. The patients with a normal nerve root course (N-NRC) had either a bony callus projecting medially into the spinal canal (n = 6) or a low mean percentile of vertebral slip (n = 4; 13.9 +/- 1.3). Those nine patients with a posteriorly deviated nerve root course (PD-NRC) had no medially projecting bony callus in the spinal canal but had a higher mean percentile of vertebral slip (n = 9; 31.5 +/- 10.1; P = 0.005). In the neural foramen, nerve roots of the N-NRC patients were entrapped craniocaudally between the pedicle and superior part of the intervertebral disc. In contrast, nerve roots of the PD-NRC patients were impinged ventrodorsally between the posterosuperior part of the intervertebral disc and either bony callus projecting inferiorly toward the neural foramen or fibrocartilaginous mass arising around the isthmic defect. The foraminal craniocaudal entrapment and ventrodorsal impingement highly agreed with the side of radicular pain (kappa= 0.73, P < 0.001). Our results demonstrate that the medially projecting bony callus and the percentile of vertebral slip affect the course of the nerve root in the neural foramen, which in turn determines the foraminal craniocaudal entrapment or ventrodorsal impingement. These two mechanisms, based on the course of the nerve root, correlate well with the side of radicular pain.

Spondylolysis of L2 in identical twins

OBJECTIVE

To discuss the presence of spondylolysis at L2 in identical twins.

CLINICAL FEATURES

Twin 61-year-old brothers reported insidious low back pain (LBP) of relatively recent onset. Both engaged in running as their main form of exercise. One had spondylolisthesis and history of significant traumatic incident; the other had no spondylolisthesis but a much more strenuous running regimen.

INTERVENTION AND OUTCOME

Both patients underwent a course of chiropractic treatment for mechanical LBP and reported a 50% overall improvement in symptoms.

CONCLUSIONS

Spondylolysis at L2 is uncommon, and although a familial component regarding weakness of the pars interarticularis has been demonstrated in the literature, spondylolysis at L2 in twins is extremely rare. Questions remain regarding the cause of spondylolisthesis in patients.

Asymmetrical spondylolysis

The objective of this study was to examine examples of spondylolysis in which the pattern of separation was clearly asymmetrical, in order to learn more about the process of bone separation that produces this condition. Although the primary focus was on unilateral complete separation, examples of asymmetry represented by incomplete separation and by complete bilateral separation where the separation sites are in different locations on the two sides were included. Two collections were used, one consisting of Canadian Inuit skeletons curated at the Canadian Museum of Civilization, and the other of 48 individual examples of asymmetrical spondylolysis from sites in a variety of localities curated by several different institutions. The first collection was studied primarily to observe early manifestations of spondylolysis, particularly incomplete separation, while various patterns of asymmetrical complete separation were the focus of the second. The results indicate that asymmetry is part of the earliest osteological picture of spondylolysis, with right-sidedness predominating, a condition perhaps related in some way to handedness. The right-side predominance appears to decrease with age. The ratio of unilateral to bilateral separation ranges from 3-33% in different studies, and a significant number of the unilateral separations have spina bifida occurring in the same vertebra. Overall, the specimens examined here, considered along with clinical cases, nicely illustrate a progression of spondylolysis. A unilateral separation may heal, it may progress to bilateral separation, or it may remain as a permanent condition, producing a pattern of degenerative changes that can include spondylolisthesis. A unilateral healing of bilateral complete separation is likely a rare phenomenon, at least after the separations have reached a certain level of maturity.

The prevalence of spondylolysis in the Spanish elite athlete

The diagnosis of spondylolysis is a major cause of concern for patients and their families, especially when the patients are young athletes with promising futures in their sports. In this study, 3152 case histories of high-level athletes were evaluated to determine which sports had a higher prevalence of spondylolysis. The overall percentage of spondylolysis among athletes in this study (8.02%) was not very much higher than that among the general population, which varies between 3% and 7%. However, when each sport was considered separately we found much higher values for some sports, with the highest percentages occurring in throwing sports (26.67%), artistic gymnastics (16.96%), and rowing (16.88%). The analysis of the biomechanical movements involved in the sports with greater prevalence of spondylolysis has led us to include the element of torsion against resistance as another possible causative factor for spondylolysis that should be added to the already known causative mechanisms, lumbar hyperextension and rotation. We have divided the sports into three risk groups according to the prevalence of spondylolysis shown and the characteristics of the sample, and we recommend systematic radiological examination of the lumbar spine in athletes considered to be at greater risk of developing spondylolysis.

Spondylolysis of the upper lumbar spine. Radiological features

To elucidate the radiological features of spondylolysis of the three upper lumbar vertebrae, review of radiology reports during an 8-year period was performed. Among 17 levels of defects in 14 patients, nine were unilateral. Among 25 defects, nine had an atypical course. In eight of nine atypical defects, the direction was vertical at the inferolateral aspect, and horizontal at the superomedial aspect. The spondylolysis of the upper lumbar spine is often unilateral and the course of the defect is frequently atypical.

Morphologic analysis of the facet joint in the immature lumbosacral spine with special reference to spondylolysis

STUDY DESIGN

Morphological analysis was performed of the facet joint of the normal and spondylolytic lumbosacral spine in children and adolescents.

OBJECTIVES

This study was performed to estimate the influence of spondylolysis on growth of the neural arch of the lumbosacral spine.

SUMMARY OF BACKGROUND DATA

The development of the facet joint and its relation to spondylolysis have not been documented in the literature.

METHODS

The dimension and orientation of the facet joint at L5/S were measured on radiographs and computed tomography scans from 144 boys without pars defects and 104 boys with pars defects. The latter group was further investigated according to the stage of pars defects. Patients in both groups were between 9 and 18 years of age.

RESULTS

Growth of the facet joint in the sagittal and transverse directions and the increase of the transverse angle were remarkable up to approximately 13 years of age. Concavity of the facet joints also progressed in children of the same age. The growth of the facet joint in patients with spondylolysis was significantly retarded as the pars defects advanced from the progressive to the terminal stage. The joint surface was more coronal in orientation and flatter in shape compared with controls.

CONCLUSIONS

The present results suggest that pars defects occurring in children disturb or retard the growth of the facet joint and that the morphological characteristics of the joint surfaces in patients with spondylolysis are the consequence of these defects.

Spondylolysis in fast bowlers: principles of prevention and a survey of awareness among cricket coaches

Back injury in general, and spondylolysis in particular, represents a serious threat to the fast bowler. Hereditary factors, poor technique, overuse, and poor preparation for fast bowling may combine to produce the 'at risk' bowler. Three first-class county coaches were interviewed to establish a level of awareness of the lesion, with an emphasis on preparation of fast bowlers and the roles of technique alteration and bowling prescription in reducing the risk of back injury.

Back injuries to fast bowlers in cricket: a prospective study

Eighty-two high performance young male fast bowlers (mean age 16.8 years) were tested immediately prior to the season for selected kinanthropometric and physiological data. Subjects were also filmed both laterally (200 Hz) and from above (100 Hz) while bowling so that their front foot impacted a force platform during the delivery stride. The players then completed a log book over the ensuing season that detailed their training and playing programmes. All cricket related injuries over this season were assessed by a sports physician who used computerized tomography to assist in the diagnosis of spinal injuries. At the completion of this season the players were grouped according to their injury status (Group 1--bony injury to a vertebra; Group 2--soft tissue injury to the back that caused the player to miss at least one game, and Group 3--no injuries). A one-way analysis of variance was used to identify if any variables were significantly (P less than 0.05) different between the three groups, and a Scheffe post hoc comparison was used to determine which groups were significantly different. Eleven per cent of the players sustained a stress fracture to a vertebra(e) (L4 to S1), while 27 per cent sustained a soft tissue injury to the back. Bowlers with a low longitudinal foot arch were more likely to develop a stress fracture than those with a high arch. Shoulder depression and horizontal flexion strength for the preferred limb and quadriceps power in the non-preferred limb were also significantly related to back injuries. Results suggest that bowlers with the above physical characteristics, who bowl with these biomechanical techniques for extended periods, are predisposed to back injuries.

Spondylolysis in Eskimo skeletons

Spondylolysis was found in 25 of 46 spines of Eskimos from Greenland, at L1 in one case, at L3 in five cases and at L4 and L5 in 14 cases each. Two spondylolytic vertebrae were seen in the same spine in nine cases. Among young individuals, spondylolysis was found in 2 out of 15 spines and in older in 23 out of 31. The prevalence of spondylolysis was higher, the fourth vertebra was more commonly affected, and spondylolysis occurred at an older age in Eskimos than in other ethnic groups.

Spondylarthrography: the demonstration of spondylolysis by apophyseal joint arthrography

Twenty selected patients with spondylolysis have been studied following apophyseal joint arthrography. In each instance a communication with the defect of the pars interarticularis was demonstrated by the extension of contrast medium from injection into the adjacent facet joint. The clinical and radiological features are described. The anatomical basis of the abnormality is presented using macroscopic and radiographic correlation from a dissected cadaveric specimen of spondylolysis. Sixty-five per cent of the patients experienced significant relief of pain symptoms when long-acting local anaesthetic was introduced into the facet joint.