Spondylolisthesis, Sacro-Pelvic Morphology, and Orientation in Young Gymnasts.

STUDY DESIGN: Cross-sectional evaluation of sacro-pelvic morphology and orientation as well as spondylolisthesis prevalence in a cohort of young gymnasts. OBJECTIVE: To evaluate the prevalence of spondylolisthesis in a cohort of gymnasts, as well as the associated demographic characteristics and sacro-pelvic morphology and orientation. SUMMARY OF BACKGROUND DATA: Numerous studies have shown that sagittal sacro-pelvic morphology and orientation is abnormal in spondylolisthesis. Sacro-pelvic morphology and orientation in gymnasts and their relationship with spondylolisthesis have never been analyzed. METHODS: Radiologic evaluation of 92 gymnasts was performed to identify spondylolisthesis, and to measure pelvic incidence, pelvic tilt, sacral slope, and sacral table angle. In the presence of spondylolisthesis, the slip percentage was measured. Different demographic and training characteristics were evaluated. Radiographic parameters were compared with reference values published for asymptomatic children and adolescents, and for subjects with spondylolisthesis. RESULTS: A 6.5% prevalence of spondylolisthesis was found in our cohort. The weekly training schedule was the only statistically significant different demographic characteristic between the 2 groups, at 20.6±5.4 versus 14.4±5.6 h/wk for subjects with and without spondylolisthesis, respectively. Pelvic incidence, pelvic tilt, sacral slope, and sacral table angle were 69±20, 15±13, 54±11, and 88±7 degrees in gymnasts with spondylolisthesis, and 53±11, 10±6, 43±9, and 94±6 degrees in gymnasts without spondylolisthesis, respectively. When compared with asymptomatic individuals, pelvic incidence and pelvic tilt were slightly superior in gymnasts without spondylolisthesis. Pelvic incidence, sacral slope, and sacral table angle were significantly different between gymnasts with and without spondylolisthesis. CONCLUSIONS: The prevalence of spondylolisthesis in young gymnasts was similar to that observed in the general population. Sagittal sacro-pelvic morphology and orientation was abnormal in gymnasts with spondylolisthesis. Sagittal sacro-pelvic morphology and orientation was also slightly different in gymnasts without spondylolisthesis when compared with the normal population. The present study supports an association between spondylolisthesis and abnormal sacro-pelvic orientation and morphology.

Lymphoedema in tuberous sclerosis: case report and review of the literature.

BACKGROUND: Tuberous sclerosis has been associated with lower extremity lymphoedema in rare cases, only in females. Our objective was to increase present knowledge about this condition by describing this association of lower limb lymphoedema and tuberous sclerosis, however, in a male patient. METHODS: We report the case of a 5-year-old boy who presented with left lower limb congenital lymphoedema and was diagnosed with tuberous sclerosis 9 days after birth based on adequate clinical criteria. This patient's lymphoedema was severe and caused compartment syndrome requiring fasciotomies at 2 days after birth, numerous surgical interventions for chronic wounds and eventually necessitating several toe amputations. A biopsy confirmed benign vascular lymphatic malformation and genetic analysis confirmed the TSC2 mutation. A thorough literature review using the Medline database from 1948 to August 2013 was conducted to investigate the possible association between lower extremity lymphoedema and tuberous sclerosis. RESULTS: Our literature review confirms that the 5 reported cases of the association between lower extremity lymphoedema and tuberous sclerosis were all in female patients. Our case is the first, to our knowledge, to identify that the cause of lymphoedema is biopsy-proven benign vascular lymphatic malformation and to confirm that this association may occur in male patients as well. CONCLUSIONS: Although the true incidence is unknown, there exists a rare association between tuberous sclerosis and lower extremity lymphoedema, both in female and male patients, which may be severe and lead to compartment syndrome as well as other complications throughout development, including chronic wounds, eventually requiring amputations. A multidisciplinary team approach should be strongly considered. LEVEL OF EVIDENCE: Level V (case report).

Neurological outcome and management of pedicle screws misplaced totally within the spinal canal.

STUDY DESIGN: This study reports 9 cases referred to our institution after surgical correction of adolescent idiopathic scoliosis and pedicle screws misplaced totally within the spinal canal. OBJECTIVE: To assess the neurological outcome associated with pedicle screws misplaced totally within the spinal canal. SUMMARY OF BACKGROUND DATA: The prevalence of neurological complications from misplaced pedicle screws might be under-reported, and optimal management of pedicle screws misplaced totally within the spinal canal remains unclear. METHODS: Nine cases with pedicle screws misplaced totally within the spinal canal during posterior surgery for adolescent idiopathic scoliosis were reviewed. All cases presented at least 1 medially misplaced pedicle screw, with spinal canal intrusion greater than pedicle screw diameter, that is, completely within the spinal canal. Percentage of spinal canal intrusion was measured from computed tomographic scans. RESULTS: Spinal canal intrusion varied from 21% to 61%. In 2 patients, misplacement of pedicle screws was recognized intraoperatively and all implants were removed. They both had motor deficits from which 1 patient recovered completely. Two patients had early postoperative postural headache that disappeared after removal of the misplaced screw. Five patients had uneventful early postoperative course. One of these developed a Brown-Sequard syndrome 2 years after surgery and underwent complete implant removal. Another patient developed left thoracic paresthesia 3 years after surgery, and complete implant removal was performed. Two neurologically intact patients had uneventful implant removal after infection. The last patient refused implant removal and remained asymptomatic 5 years after surgery. CONCLUSION: Improper pedicle screw placement can lead to neurological complications appearing early or late (after 2 yr). Late neurological complications were associated with screw loosening in 2 cases. The authors strongly recommend removal of any pedicle screw misplaced totally within the spinal canal due to the risk of early or late neurological complications, regardless of the severity of spinal canal intrusion.

Prevalence of spondylolisthesis in a population of gymnasts.

Spondylolysis occurs in 6 % of the general population. Of these, approximately 75% will develop spondylolisthesis. According to multiple studies, an increased prevalence of spondylolysis and spondylolisthesis exists in groups of athletes practicing certain sports such as gymnastics. In the literature, prevalence of spondylolisthesis in gymnasts can reach up to 40 to 50 %. However, the specific risk factors associated with the development of spondylolisthesis in gymnasts are not known. The main purpose of this study was to evaluate the prevalence of spondylolysis and spondylolisthesis in a population of gymnasts, as well as the associated epidemiological characteristics. In order to achieve this goal, we presented our project to the two most renowned gymnastics centers in the city of Montreal, which allowed us to recruit a total of 93 gymnasts (19 males and 74 females). A radiological evaluation, with the low emission radiographic system, EOS, allowed us to identify the subjects that were affected by spondylolysis and spondylolisthesis. Additionally, standardized questionnaires allowed us to evaluate and compare different epidemiologic parameters such as age, height, weight, number of years of practice, number of hours of training per week. Of the 93 gymnasts evaluated clinically and radiographically, we identified 6 (1 male, 5 females) gymnasts presenting a spondylolysis and/or spondylolisthesis. This 6.5% prevalence found in our population is similar to the one reported in the general population. Gender did not seem to be a determinant factor. Also, gymnasts with and without spondylolysis and/or spondylolisthesis seemed to be similar in terms of height. However, gymnasts with spondylolysis and/or spondylolisthesis seemed to be heavier than gymnasts without one of these two affections, older and training with greater intensity. These results suggest that the real prevalence rate of spondylolysis and spondylolisthesis in gymnasts may have been overestimated in previous studies. A selection bias, due to the high competitive level in the two gymnastics centers where our recruitment took place, could be involved. Our findings could also be the result of new or different training methods compared to those used in past studies. This might suggest that with intense training schedules, heavier individuals could potentially be prone to increased loads at the lumbosacral junction, thus favoring the development of spondylolysis and spondylolisthesis. These hypotheses should be explored in further details in the near future, especially with investigation of radiological parameters of the spine and pelvis.

Cell-based screening test for idiopathic scoliosis using cellular dielectric spectroscopy.

STUDY DESIGN: A cell-based assay was developed to identify asymptomatic children at risk of developing idiopathic scoliosis (IS) and to stratify IS patients at an earlier stage in order to better predict their clinical outcome. Clinical validation of this assay was performed by testing IS patients at different stages, healthy control subjects, and asymptomatic offspring, born from at least one scoliotic parent, who are considered at risk of developing this disorder. OBJECTIVE: Our goal was to develop and validate a clinical test for IS using cellular dielectric spectroscopy (CDS) and peripheral blood mononuclear cells (PBMCs). SUMMARY OF BACKGROUND DATA: We have previously demonstrated the occurrence of a melatonin signaling dysfunction in osteoblasts obtained from severely affected IS patients using a cAMP assay. This led us to stratify IS patients into 3 functional subgroups. METHODS: A group of 44 patients with IS was compared with 42 healthy control subjects and 31 asymptomatic at-risk children. PBMCs were obtained after centrifugation on a Ficoll-gradient. Melatonin signal transduction was measured by CDS in the presence of varying concentrations of melatonin or iodomelatonin. RESULTS: Osteoblasts from distinct functional subgroups were retested using CDS, allowing their classification into the same functional subgroups with both ligands as initially demonstrated using a cAMP assay. Clinical data obtained with CDS and PBMCs showed 100% specificity and 100% sensitivity because melatonin signaling impairment was observed only in IS patients and not in healthy controls. Assessment of the risk of developing a scoliosis in asymptomatic children was determined by CDS in 33% of asymptomatic children at risk, which was confirmed clinically within 24 months. CONCLUSION: This cell-based assay can serve as a presymptomatic screening test to identify asymptomatic children at risk of developing IS and may be used to improve stratification of patients, which in turn allow clinicians to predict their clinical outcome. Moreover, this functional blood test is advantageous because it can be performed without prior knowledge of specifically mutated genes causing IS.

[Etiopathogenesis of adolescent idiopathic scoliosis and new molecular concepts]. / Récents progrès dans l'étiopathogénie de la scoliose idiopathique de l'adolescent et nouveaux concepts moléculaires.

Adolescent idiopathic scoliosis (AIS) is the most common form of scoliosis that affects a significant number of young teenagers, mainly females (0.2-6 % of the population). Historically, several hypothesis were postulated to explain the aetiology of AIS, including genetic factors, biochemical factors, mechanics, neurological, muscular factors and hormonal factors. The neuroendocrine hypothesis involving a melatonin deficiency as the source for AIS has generated great interest. This hypothesis stems from the fact that experimental pinealectomy in chicken, and more recently in rats maintained in a bipedal mode, produces a scoliosis. The biological relevance of melatonin in idiopathic scoliosis is controversial since no significant decrease in circulating melatonin level has been observed in a majority of studies. Analysis of melatonin signal transduction in musculoskeletal tissues of AIS patients demonstrated for the first time a defect occurring in a cell autonomous manner in different cell types isolated from AIS patients suffering of the most severe form of that disease. These results have led to a classification of AIS patients in three different functional groups depending on their response to melatonin, suggesting that the cause of AIS involves several genes. Molecular analysis showed that melatonin signaling dysfunction is triggered by an increased phosphorylation of Gi proteins inactivating their function. This discovery has led to development of a first scoliosis screening assay. This test, using blood sample, is currently in clinical validation process in Canada and could be used for screening children at high risk of developing AIS.

Assessment of sacral doming in lumbosacral spondylolisthesis.

STUDY DESIGN: Quantitative versus subjective evaluation of sacral doming in lumbosacral spondylolisthesis. OBJECTIVES: To evaluate the relevance of the Spinal Deformity Study Group (SDSG) index in the assessment of sacral doming and to propose a quantitative criterion to differentiate between significant and nonsignificant doming. SUMMARY OF BACKGROUND DATA: There is no consensus on the optimal technique to assess sacral doming, although it is an important feature in spondylolisthesis. METHODS: Five spinal surgeons subjectively assessed the sacral endplate of 100 subjects (34 high-grade spondylolisthesis, 50 low-grade spondylolisthesis, 16 controls) from lateral radiographs. Subjects were classified by each surgeon as having significant or nonsignificant sacral doming. An independent observer quantitatively evaluated sacral doming for all subjects using the SDSG index. A criterion to differentiate significant from nonsignificant sacral doming was sought, based on the comparison between the subjective assessment of surgeons and the quantitative evaluation by the independent observer. Intrarater and interrater reliability of the SDSG index was evaluated using intraclass correlation coefficient (ICC). RESULTS: Intrarater and interrater ICCs for the SDSG index were excellent at 0.91 and 0.88, respectively. Sacral doming evaluated with the SDSG index was 11.6% +/- 5.0% (range, 1.5%-18.9%), 16.4% +/- 6.3% (range, 3.7%-35.6%), and 27.9% +/- 10.9% (range, 5.7%-56.9%) for controls, low-grade, and high-grade cases, respectively. Overall intersurgeon agreement on the significance of sacral doming was substantial at 88% (kappa = 0.72). With a threshold value of 25% for the SDSG index, 93% of concordance was found between the quantitative evaluation using the SDSG index and the multisurgeons subjective assessment. CONCLUSION: This study confirms the relevance of the SDSG index to assess sacral doming in lumbosacral spondylolisthesis. The authors propose a criterion of 25% to differentiate significant from nonsignificant sacral doming using the SDSG index. Such a criterion will allow more accurate assessment of sacral remodeling, especially for borderline cases, and facilitate comparisons between studies.

Melatonin signaling dysfunction in adolescent idiopathic scoliosis.

STUDY DESIGN: In vitro assays were performed with bone-forming cells isolated from 41 patients with adolescent idiopathic scoliosis and 17 control patients exhibiting another type of scoliosis or none. OBJECTIVE: To determine whether a dysfunction of the melatonin-signaling pathway in tissues targeted by this hormone is involved in adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Pinealectomy in chicken has led to the formation of a scoliotic deformity, thereby suggesting that a melatonin deficiency may be at the source of adolescent idiopathic scoliosis. However, the relevance of melatonin in the etiopathogenesis of that condition is controversial because most studies have reported no significant change in circulating levels of melatonin in patients with adolescent idiopathic scoliosis. METHODS: Primary osteoblast cultures prepared from bone specimens obtained intraoperatively during spine surgeries were used to test the ability of melatonin and Gpp(NH)p, a GTP analogue, to block cAMP accumulation induced by forskolin. In parallel, melatonin receptor and Gi protein functions were evaluated by immunohistochemistry and by coimmunoprecipitation experiments. RESULTS: The cAMP assays demonstrated that melatonin signaling was impaired in osteoblasts isolated from adolescent idiopathic scoliosis patients to different degrees allowing their classification in 3 distinct groups based on their responsiveness to melatonin or Gpp(NH)p. CONCLUSION: Melatonin signaling is clearly impaired in osteoblasts of all patients with adolescent idiopathic scoliosis tested. Classification of patients with adolescent idiopathic scoliosis in 3 groups based on functional in vitro assays suggests the presence of distinct mutations interfering with the melatonin signal transduction. Posttranslational modifications affecting Gi protein function, such as serine residues phosphorylation, should be considered as one possible mechanism in the etiopathogenesis of AIS.

The effect of intraoperative traction during posterior spinal instrumentation and fusion for adolescent idiopathic scoliosis.

STUDY DESIGN: A retrospective study comparing patients having traction and a control group not having traction during posterior spinal instrumentation and fusion (PSIF) for adolescent idiopathic scoliosis (AIS). OBJECTIVE: To evaluate the effect of intraoperative traction on surgical correction of AIS. SUMMARY OF BACKGROUND DATA: When the Cotrel-Dubousset instrumentation system was introduced, the use of intraoperative traction was advocated. However, there is no specific report documenting the effect of intraoperative traction on the correction of AIS. METHODS: The medical and radiologic records of 140 AIS patients treated by PSIF were reviewed. Forty of these patients had intraoperative traction using a head halter associated with lower extremity skin traction. The radiologic outcome was compared between the two groups intraoperatively (before instrumentation with the first rod) and after surgery using Student t tests (level of significance = 0.05). RESULTS: The intraoperative and postoperative corrections of the coronal primary Cobb angle were similar for both groups, although the patients in the traction group had smaller preoperative Cobb angles and more flexible curves and were instrumented with more screws. The postoperative thoracic kyphosis was significantly increased in both groups. The lumbar lordosis at the 1-year follow-up was maintained in the control group, but it was significantly decreased in the traction group. CONCLUSION: The authors do not recommend the routine use of intraoperative traction using a head halter combined with skin traction for all AIS patients undergoing PSIF. However, it could be helpful in selected cases, such as in patients having pelvic obliquity and requiring instrumentation of the pelvis.