Abnormal eyes and spine development in zebrafish (Danio rerio) embryos and larvae induced by triphenyltin

Triphenyltin (TPT) is widely used in crop pest control and ship antifouling coatings, which leads to its entry into aquatic environment and poses a threat to aquatic organisms. However, the effects of TPT on the early life stages of wild fish in natural water environments remains unclear. The aim of this study was to assess the toxic effects of TPT on the early life stages of fish under two different environments: field investigation and laboratory experiment. The occurrence of deformities in wild fish embryos and larvae in the Three Gorges Reservoir (TGR) and the developmental toxicity of TPT at different concentrations (0, 0.15, 1.5 and 15 μg Sn/L) to zebrafish embryos and larvae were observed. The results showed that TPT content was higher in wild larvae, reaching 27.21 ng Sn/g w, and the malformation of wild fish larvae mainly occurred in the eyes and spine under natural water environment. Controlled experiment exposure of zebrafish larvae to TPT also resulted in eye and spinal deformities. Gene expression analysis showed that compared with the control group, the expression levels of genes related to eye development (sox2, otx2, stra6 and rx1) and spine development (sox9a and bmp2b) were significantly up-regulated in the 15 μg Sn/L exposure group, which may be the main cause of eye and spine deformity in the early development stage of fish. In addition, the molecular docking results further elucidate that the strong hydrophobic and electrostatic interactions between TPT and protein residues are the main mechanism of TPT induced abnormal gene expression. Based on these results, it can be inferred that TPT is one of the teratogenic factors of abnormal eye and spine development in the early life stage of fish in the TGR. These findings have important implications for understanding the toxicity of TPT on fish.

Correlation analysis of the PI-LL mismatch according to the pelvic incidence from a database of 468 asymptomatic volunteers

PURPOSE

Previous studies on adults with degenerative scoliosis (ADS) have been fixed the threshold of PI-LL mismatch less than 10° for achieving good clinical outcomes. Recent studies discussed that PI-LL mismatch should consider individual pelvic incidence (PI) and should be set first in a normal population. The purpose of this study is to assess the variability of PI-LL mismatch according to PI in an asymptomatic population.

METHODS

Full-body low dose stereoradiographic evaluation was done in a multi-ethnic cohort of 468 asymptomatic adult volunteers. Patients were clustered in three groups depending on individual PI values: PI < 45°, 45° < PI < 60° and PI > 60°. 3D measurements were performed using a commercially available 2D/3D modeling software to establish a correlation of PI with other spinopelvic parameters. ANOVA and Tukey's HSD for post-hoc analysis were used to determine the differences between the three groups.

RESULTS

In our asymptomatic population, the mean value of PI-LL mismatch is - 5.4° ± 10.7°. Clusterization of the population reveals significant differences in the distribution of L1S1 lordosis, pelvic tilt and PI-LL with positive linear correlation according to PI values. As an interestingly result, PI-LL mismatch is equal to 0° when PI is around 64°.

CONCLUSIONS

The present study demonstrated that PI-LL mismatch is negative in an asymptomatic population (- 5.4° ± 10.7°) and the value should be customized to each patient to be able to restore the appropriate lordosis in ADS. The PI-LL mismatch is given by the formula PI-LL = - 28.5 + 0.44 × PI.

Pulmonary Implications of Pediatric Spinal Deformities

"Pediatric spinal deformities may be associated with pulmonary complications in a patient's lifetime. A review of the diagnosis of spinal abnormalities includes classifications of scoliosis and kyphosis, correlating physical examination findings and radiographic interpretation. The natural history of untreated spine deformities is reviewed along with the associated altered pulmonary compromise. Treatment options for children affected by spinal deformities are discussed, including the relative indications, the efficacy, pros and cons of different treatment options, along with the evidence to support these. This overview of spine deformities includes research outcomes to support the care of these pediatric patients."

短期头盆环牵引配合手术治疗重度脊柱畸形的临床疗效

OBJECTIVE

To evaluate the clinical efficacy of short-term halo-pelvic traction (HPT) combined with surgery in the treatment of severe spinal deformities.

METHODS

In the study, 24 patients diagnosed as severe spinal deformity accepted the treatment of one-stage short-term HPT and two-stage surgery from January 2015 to May 2018 in our orthopedics department. 24 cases (9 males and 15 females) were retrospectively reviewed. The average age of the cohort was (28.8±10.0) years (12－48 years). The height, scoliosis angle, kyphosis angle, the height difference of shoulders, the height difference of crista iliaca, C7PL-CSVL and the perpendicular distance of S1 and the convex point of the patients were assessed at pre-traction, post-traction and post-surgery. The paired t test was used to analyze the difference among pre-traction, post-traction and post-surgery.

RESULTS

The average traction time of 24 cases was (2.5±1.1) weeks (1－5 weeks). The height of pre-traction and post-traction were (141.7±11.2) cm (116-167 cm) and (154.1±9.5) cm (136－176 cm) respectively, showing significant difference (P < 0.05), and the increased height was (12.4±4.6) cm (4－20 cm). The average scoliosis angle before traction was 104.9°±35.0°(25°－158°), and it was significantly decreased in post-traction[64.8°±21.0°(19°－92°)] and post-surgery[39.3°±17.0° (10°-70°)] (P < 0.05). The traction's coronal correction rate was 37.2%±10.9% (11.9%－51.2%) and the total coronal correction rate was 61.9%±12.6%(26.9%-79.0%). The average kyphosis angle before traction was 106.9°±29.2°(54°－163°), and it was significantly decreased in post-traction [63.1°±17.1°(32°－92°)] and post-surgery [39.0°±16.8°(10°－68°)](P < 0.05). The traction's sagittal correction rate was 40.0%±10.7%(16.7%－55.5%) and the total sagittal correction rate was 64.3%±10.7%(49.0%－87.5%). The average C7PL-CSVL before traction was (3.2±2.8) cm, and it was significantly decreased in post-traction [(2.5±2.5) cm] (P < 0.05). The perpendicular distance of S1 and the convex point before traction was (10.5±4.8) cm, and it was significantly decreased in post-traction[(8.4±3.5) cm] (P < 0.05).

CONCLUSION

The one-stage short-term HPT combined with two-stage surgery is a safe and effective procedure for severe spinal deformities. The clinical efficacy is satisfactory and the complication is relatively less.

[Etiology and significance of growth disturbances of the spine]

BACKGROUND

The majority of growth disturbances of the spine are acquired and their etiology is still unknown. Both scolioses and sagittal profile disorders are most commonly of idiopathic origin.

ETIOLOGY

The etiology is multifactorial and besides genetic, hormonal and mechanical factors also metabolic components seem to be involved. The risk of progression of an existing deformity is particularly high during the pubertal growth spurt. Accordingly, regular clinical and radiological controls should be carried out in this vulnerable period. Recently, spinal deformities have been classified according to the time of diagnosis rather than according to their etiology, considering the increasing knowledge about the correlation between spinal and thoracic growth and the associated maturation of the lungs. Therefore, the term "early onset scoliosis" considers all deformities of the spine diagnosed before the age of 10 years.

TREATMENT

In the case of failure of conservative treatment options, which have to be applied for as long as possible, definitive spinal fusion surgery should be delayed by the use of growth-sparing surgical techniques, aiming to achieve as normal pulmonary function as possible.

Does spinal deformity correction of non-dystrophic scoliosis in neurofibromatosis type I with one-stage posterior pedicle screw technique produce outcomes similar to adolescent idiopathic scoliosis?

BACKGROUND CONTEXT

The efficacy of one-stage posterior pedicle screw instrument used in the treatment of non-dystrophic scoliosis in neurofibromatosis type I (NF-1) is unknown. Also, there is no study that has directly compared the results of spinal deformity correction between non-dystrophic scoliosis in NF-1 and adolescent idiopathic scoliosis (AIS).

PURPOSE

The objectives of this study were to study the efficacy of a one-stage posterior pedicle screw instrument used in the treatment of non-dystrophic scoliosis in NF-1 and to compare non-dystrophic scoliosis in NF-1 with matched AIS to illustrate the differences.

STUDY DESIGN

This is a retrospective case control study.

PATIENT SAMPLE

Fifteen patients with non-dystrophic scoliosis in NF-1 and 15 patients with AIS underwent a one-stage posterior surgery with the pedicle screw system.

OUTCOME MEASURES

Preoperative and postoperative whole-spine radiographs were used to determine coronal and sagittal Cobb angles. Also, the distance between the C7 plumb line and the center sacral vertical line and the sagittal vertebral axis was measured to assess spinal balance. The Scoliosis Research Society (SRS)-22 questionnaire was used to evaluate functional outcomes.

METHODS

We matched 15 patients with non-dystrophic scoliosis in NF-1 with patients with AIS (ratio, 1:1) for age, sex, and degree of major deformity. The overall mean age was 13.4±2.0 and 14.0±2.1 years, respectively. The NF-1 group consisted of 10 boys and 5 girls, and the AIS group consisted of 9 boys and 6 girls. The mean follow-up was 37.6±3.9 and 33.5±5.0 months, respectively. The AIS group underwent end vertebra (EV) or EV+1 fusion. The NF-1 group underwent EV+1, 2, or 3 fusion. Both coronal and sagittal Cobb angles, trunk balance, operative time, blood loss, fusion levels, length of stay, and scores on the SRS-22 questionnaire were compared between the two groups. The study was supported by the National Natural Science Foundation of China (Grant No. 81401760). There were no study-specific conflict of interest-associated biases.

RESULTS

The preoperative main curve magnitude was similar between the two groups; however, the flexibility of the NF-1 group tended to be less than that of the AIS group. The rate of correction of the main curve obtained surgically (79.8% compared with 81.1%) was similar in the NF-1 and AIS groups. There were no significant differences in the loss of correction between the two groups (p>.05). Also, there were no significant differences between the groups in operative time, blood loss, fusion levels, screw number, length of stay, trunk balance, and scores on the SRS-22. There were no serious complications related to surgery in both groups.

CONCLUSIONS

Despite the differences in preoperative flexibilities and fusion strategies, non-dystrophic scoliosis in NF-1 can be treated with a satisfied correction rate and progression rate similar to comparable AIS by using the one-stage posterior pedicle screw technique. Dural ectasia or thin pedicles in non-dystrophic scoliosis could make pedicle screw placement challenging.

Spinal cord tumors in children: A review of 21 cases treated at the same institution

INTRODUCTION

Spinal cord tumors in children (SCTC) are rare with a frequent diagnostic delay. Its management is multidisciplinary and challenging due to functional implications. The position of surgery is now better established but the role and timing of chemotherapy (CT) and radiotherapy (RT) still remains under debate. Adverse effects of treatments are important to be taken into account, in the follow-up of these children. The aim of this paper was to present a series of 21 cases of SCTC treated at the same institution, to briefly present clinical features, treatments and outcome, with a special focus on spinal deformities in children with this condition.

MATERIAL AND METHODS

Twenty-one consecutive SCTC were referred to our institution from 1990 to 2014. Data regarding age, sex, diagnostic delay, clinical examination, MRI, surgery, pathology, other treatment (CT and RT), orthopedic issues and follow-up of these children were retrospectively recorded.

RESULTS

Mean age was 8years (standard deviation: 5.2years) (range: 4 months-17years). Mean diagnosis delay was 5.5 months (standard deviation: 6.5 months) (range: 0 days-18 months). All children (10 girls, 11 boys) were operated on (10 partial removals, 7 subtotal and 4 gross total removals) as first-line treatment. Pathological results showed 12 juvenile pilocytic astrocytomas, 1 grade III astrocytoma, 1 grade IV astrocytoma, 3 oligodendrogliomas, 2 ependymomas, 1 glioblastoma and 1 rhabdoid tumor. Fourteen children (66.7%) received additional treatment: 12 CT and 7 RT. Ten children had postoperative spinal deformities. Mean follow-up (FU) was 71 months (5 months-180 months), with a median FU at 60 months, where 8 tumor progressions and 4 deaths were observed. Overall, survival (at 5years) was 81% and progression free survival (at 5years) was 67%.

CONCLUSION

Surgery is the goal standard for SCTC and the only appropriate treatment in cases of a low-grade lesion with stable disease on MR follow-up. Additional treatment must be reserved for high-grade lesions or tumor progression not attainable by a second look surgery. Spinal deformities are a frequent complication. Overall, survival and event free survival primarily depends on the pathology. Studies involving more centers are obligatory with the aim of collecting more cases and drawing more definitive conclusions regarding the management of these tumors.

ISYQOL: a Rasch-consistent questionnaire for measuring health-related quality of life in adolescents with spinal deformities

BACKGROUND CONTEXT

Spinal deformities are commonly associated with poor health-related quality of life (HRQOL). Several questionnaires (eg, Scoliosis Research Society-24 [SRS-24] and Scoliosis Research Society-22 [SRS-22]) have been developed to evaluate HRQOL in these conditions. In adults as well as during growth, the HRQOL is considered one of the most relevant outcomes of both conservative and surgical treatments. Rasch analysis is a powerful statistical technique for developing high-quality and valid questionnaires. The SRS-24 and SRS-22 have been evaluated using the Rasch analysis but showed poor measurement properties. Thus, a proper measure of HRQOL in people with a spine condition is still missing.

PURPOSE

This study aimed to develop a new questionnaire that is totally Rasch consistent for measuring the HRQOL in young people with a spine condition.

STUDY DESIGN

This is a cross-sectional study for developing a new HRQOL measure.

PATIENT SAMPLE

A total of 402 participants with adolescent idiopathic scoliosis or Scheuermann juvenile kyphosis were included in the study.

OUTCOME MEASURE

The outcome measure used was the Italian Spine Youth Quality of Life (ISYQOL) questionnaire.

MATERIALS AND METHODS

The study consisted of different stages: a conventional approach content analysis, an opinion poll among clinicians trained in spine deformities, and the Rasch analysis (partial credit model).

RESULTS

The Rasch analysis showed that all items of the ISYQOL questionnaire had ordered thresholds and a good fit to the model. Differential item functioning was present for Item 1, with bracing only, and was solved with a conventional items splitting procedure. The ISYQOL item map spans an adequate range of HRQOL. The principal component analysis for Rasch residuals showed, in practical terms, the ISYQOL unidimensionality. The reliability of ISYQOL was high enough so that approximately three significantly different levels of HRQOL could be discerned. Two questionnaire versions were provided for patients with and without the brace, respectively.

CONCLUSIONS

ISYQOL is the first HRQOL questionnaire developed according to the Rasch analysis. It was developed in a conservative treatment setting for all types of spinal deformities, including also patients with surgical curves. Validation in many languages is already under way.

Risk factors for thoracic and spinal deformities following lung resection in neonates, infants, and children

Purpose

We aimed to identify the risk factors for thoracic and spinal deformities following lung resection during childhood and to elucidate whether thoracoscopic surgery reduces the risk of complications after lung resection.

Methods

We retrospectively examined the medical records of all pediatric patients who underwent lung resection for congenital lung disease at our institution between 1989 and 2014.

Results

Seventy-four patients underwent lung resection during the study period and were followed-up. The median age of the patients at the time of surgery was 5 months (range 1 day–13 years), and 22 were neonates. Thoracotomy and thoracoscopy were performed in 25 and 49 patients, respectively. Thoracic or spinal deformities occurred in 28 of the 74 patients (37%). Univariate analyses identified thoracotomy, being a neonate (age: <1 month) at the time of surgery, and being symptomatic at the time of surgery as risk factors for these deformities. However, a multivariate analysis indicated that only thoracotomy and being a neonate were risk factors for deformities.

Conclusions

Thoracoscopic surgery reduced the risk of thoracic and spinal deformities following lung resection in children. We suggest that, where possible, lung resection should be avoided until 2 or 3 months of age.

Modified iliac screw fixation: technique and clinical application

BACKGROUND

A conventional iliac bolt and the S2 alar iliac screw fixation technique (S2AI) are commonly used sacropelvic fixation techniques. However, conventional iliac bolt technique requires a lateral connector and commonly has prominent screw head problems. S2AI reportedly has a high instrument failure rate. We aim to introduce a modified iliac screw fixation technique and to investigate its clinical application in adult patients.

METHODS

The entrance site of the modified iliac screw fixation technique was 1 cm medial and 1 cm caudal from the posterosuperior iliac spine. From 2009 to 2015, ten adult patients underwent sacropelvic fixation with the modified iliac screw fixation technique in our spine clinic. A minimum 12-month clinical and radiographic follow-up was adopted. The mean follow-up period was 30.7 months (12-74 months). Mean number of fixation levels was 7.7 segments (5-10 segments).

RESULTS

Postoperatively, the C7 plumb line (SVA) was significantly decreased (P = 0.04). Upon the last X-ray, SVA did not differ between postoperative and the last X-ray (P = 0.1). There was no breakage during our follow-up period. There was no prominent screw head. There were no cases requiring implant removal.

CONCLUSIONS

The modified iliac screw fixation technique does not cause prominence in the sacral region, and does not require a lateral connector, both of which are necessary when using the classical iliac bolt technique. This technique also avoids the acute angle between the screw head and the shaft of the screw commonly seen in S2AI. The modified iliac screw fixation technique can be an effective alternative for sacropelvic fixation.

Prevalence of thoracic scoliosis in adults 25 to 64 years of age detected during routine chest radiographs

PURPOSE

To investigate the prevalence of thoracic scoliosis and determine the effect of both age and gender on coronal curve magnitude among asymptomatic adults aged 25-64 years old, using standing posterior-anterior chest radiographs.

METHODS

This was a retrospective, cross-sectional study evaluating 500 randomly selected digital posterior-anterior chest radiographs taken at a single institution on an outpatient basis between January 2010 and December 2011. Males (n = 184) and females (n = 316) ranged in age from 25 to 64 years. Patients with symptoms of back pain; including a history of back pain, spinal instrumentation, or known pre-existing spinal disease were excluded. Radiographs were evaluated using Centricity PACS Web Diagnostic 2.1 system (General Electric Co. Fairfield, CT). Coronal Cobb angle measurements of the thoracic spine were quantified by the authors, with scoliosis defined as coronal curves greater than 10°. Curvatures were subdivided into groups: a control group with coronal curves less than 10°, curves measuring 10° to 19°, 20° to 29°, and greater than 30°. The effect of age and gender on curve magnitude was examined using Pearson correlation analysis and linear regression analysis.

RESULTS

There was a 13.4 % (67 patients) prevalence of thoracic scoliosis. The prevalence among asymptomatic males was 10.9 %, while the prevalence among asymptomatic females was 14.9 %. 11.6 % demonstrated a coronal curvature between 10° and 19° (58 patients), 1.6 % between 20° and 29° (8 patients), and 0.2 % greater than 30° (1 patient). Age and gender were not found to be significant independent predictors of curve severity.

CONCLUSIONS

We found a 13.4 % prevalence of thoracic scoliosis among asymptomatic adults aged 25-64 years on routine outpatient chest radiographs. 11.6 % of patients demonstrated a coronal curvature between 10° and 19°. Unlike prior studies evaluating asymptomatic thoracic curves in elderly patients, age and gender did not significantly affect curve magnitude in our younger cohort. These data may provide a reference point to help clinicians counsel asymptomatic patients diagnosed with thoracic scoliosis on routine chest radiographs.

Preliminary investigation of high-dose tranexamic acid for controlling intraoperative blood loss in patients undergoing spine correction surgery

BACKGROUND CONTEXT

With a significant increase in the number and complexity of spinal deformity corrective surgeries, blood loss, often requiring massive intraoperative transfusions, becomes a major limiting factor during surgery. This scenario is particularly during posterior vertebral column resection (PVCR), where extensive intraoperative blood loss may pose a major risk to the patient, preventing smooth execution of the procedure. Tranexamic Acid (TXA) has been used in cardiac and orthopedic surgeries, including major spinal surgeries, to reduce blood loss and transfusion requirements for decades.

PURPOSE

To assess the efficacy and safety of high doses of TXA in posterior spinal deformity corrective surgery, including PVCR procedures.

STUDY DESIGN

A retrospective study from a single institution.

PATIENT SAMPLE

Fifty-nine patients (age range 7 to 46 years old) with spinal deformities undergoing spinal corrective surgeries were included. The patients were divided into two groups: the TXA group (total of 26 patients, including 8 PVCR patients) and the control group (total of 33 patients, including 9 PVCR patients).

OUTCOME MEASURES

The analyzed outcome measures included estimated intraoperative blood loss, real blood loss (RBL; blood loss/blood volume×100%), blood transfusion requirements, coagulation parameters, complete blood count, liver function, and renal function. Lower limb vein thrombus, symptomatic pulmonary embolism, symptomatic myocardial infarction, seizures, and acute renal failure were also recorded.

METHODS

Before skin incision, the patients in the TXA group received an intravenous loading dose of 100 mg/Kg over a 20-minute period, followed by a maintenance infusion of 10 mg/Kg/h until skin closure was completed. The patients in the control group received saline infusion of a similar volume. Statistics included estimated intraoperative blood loss, RBL, blood transfusion requirements, coagulation parameters, complete blood count, liver function, and renal function. All patients in this study were also carefully monitored for consciousness level, breathing status, chest tightness or pain, and urine output after surgery. These were done to detect the presence or absence of pulmonary embolism, myocardial infarction, seizures, and acute renal failure. Patients treated with TXA were examined via vascular ultrasound before and after surgery.

RESULTS

There were no significant differences in the demographic or surgical traits between the two groups. The blood loss of the patients in the TXA group was 2,441±1,666 mL, whereas that of the control group patients was 4,789±4,719 mL. The difference was statistically significant (p<.05). The average RBL of the patients in the TXA group was 80.6%±49.6% versus 160.8%±163.1% in the control group (p<.05). The blood transfusion requirements for the patients in the TXA group were significantly less than that in the control group (p<.05). Blood loss, RBL, and blood transfusion requirements were all significantly lower in the TXA group, compared with the control group among both PVCR patients and non-PVCR patients. In the TXA group, there was an average of 57.4% reduced blood loss in patients who received PVCR and 39.8% in patients not receiving PVCR. There were no differences in liver and renal functions between the TXA and control groups. There was no lower limb vein thrombus, symptomatic myocardial infarction, symptomatic pulmonary embolism, seizures, or acute renal failure reported in the TXA group.

CONCLUSIONS

In our study, high doses of TXA have been shown to effectively control blood loss and reduce the transfusion requirement. This effect was more apparent in patients receiving PVCR. No adverse drug reaction was recorded in the study. In the future, prospective randomized controlled trials to validate our results will be necessary. Future studies conducted on older patient cohort may also be necessary to confirm the safety of extending the use of TXA to the older patients.

Spinal deformities in a wild line of Poecilia wingei bred in captivity: report of cases and review of the literature

OBJECTIVE

To describe the occurrence of various spinal deformations in a captive-bred wild line of Poecilia wingei (P. wingei).

METHODS

Fish belonging to a wild line of P. wingei caught from Laguna de Los Patos, Venezuela, were bred in an aquarium home-breeding system during a period of three years (2006-2009). The spinal curvature was observed to study spinal deformities in P. wingei.

RESULTS

Out of a total of 600 fish, 22 showed different types of deformities (scoliosis, lordosis, kyphosis), with a higher incidence in females. Growth, swimming and breeding of deformed fish were generally normal.

CONCLUSIONS

Possible causes for spinal curvature in fish are discussed on the basis of the current literature. While it is not possible to determine the exact cause(s) of spinal deformities observed in the present study, traumatic injuries, nutritional imbalances, genetic defects or a combination of these factors can be supposed to be involved in the pathogenesis of such lesions.

Association between body mass index, body height, and the prevalence of spinal deformities

BACKGROUND CONTEXT

The most common spinal deformities among adolescents are adolescent idiopathic scoliosis (AIS; 2%-3% prevalence) and Scheuermann kyphosis (SK; 1%-8% prevalence). Both are believed to have a genetic influence in their etiology. The association between body mass index (BMI) and body stature and their possible association to spinal deformities is uncertain.

STUDY DESIGN

A cross-sectional prevalence study.

PURPOSE

To examine the prevalence of all adolescent spinal deformities according to the extent of their severity as well as their possible association to BMI and body height.

OUTCOME MEASURES

Subjects diagnosed as having spinal deformities were classified into one of three severity groups; "Mild," "Intermediate," or "Severe," according to their curve scoliosis or kyphosis measurement with a standing X-ray.

METHODS

The data for this study were derived from a medical database containing records of 17-year-old male and female patients before their recruitment into mandatory military service. Information on the disability codes associated with spinal deformities according to the Regulations of Medical Fitness Determination was retrieved. Logistic regression models were used to assess the association between the BMI and body height to various degrees of spinal deformities by severity.

RESULTS

The study cohort included 829,791 consecutive subjects, of whom 103,249 were diagnosed with spinal deformities (76% were mild in degree). The prevalence of spinal deformities was significantly greater among the underweight male and female patients (p<.001). Increased BMI had a protective effect for developing spinal deformities. The odds ratios for severe spinal deformities were greater compared with mild spinal deformities in the underweight groups. The risk for developing spinal deformities increased significantly with height for both genders (p<.001).

CONCLUSIONS

An association between height and the risk for spinal deformities by severity was found for all height groups. Below normal BMI is associated with severity of spinal deformities, whereas above-normal BMI apparently has a protective effect. Body height is also positively associated with the severity of spinal deformities.

Neurophysiological changes during shortening osteotomies of the spine

BACKGROUND CONTEXT

Kyphotic deformities with sagittal imbalance of the spine can be treated with spinal osteotomies. Those procedures are known to have a high incidence of neurological complications, in particular at the thoracic level. Motor evoked potentials (MEPs) have been widely used in helping to avoid major neurological deficits postoperatively. Previous reports have shown that a significant proportion of such cases present with important transcranial MEP (Tc-MEP) changes during surgery with some of them being predictive of postoperative deficits.

PURPOSE

Our aim was to study Tc-MEP changes in a consecutive series of patients and correlate them with clinical parameters and radiological changes.

STUDY DESIGN/SETTING

Retrospective case notes study from a prospective patient register.

PATIENT SAMPLE

Eighteen patients undergoing posterior shortening osteotomies (nine at thoracic and nine at lumbar levels) for kyphosis of congenital, degenerative, inflammatory, or post-traumatic origin were included.

OUTCOME MEASURES

Loss of at least 80% of Tc-MEP signal expressed as the area under the curve percentual change, of at least one muscle.

METHODS

We studied the relation between outcome measure (80% Tc-MEP loss in at least one muscle group) and amount of posterior vertebral body shortening as well as angular correction measured on computed tomography scans, occurrence of postoperative deficits, intraoperative blood pressure at the time of the osteotomy, and hemoglobin (Hb) change.

RESULTS

All patients showed significant Tc-MEP changes. In particular, greater than 80% MEP loss in at least one muscle group was observed in five of nine patients in the thoracic group and four of nine patients in the lumbar group. No surgical maneuver was undertaken as a result of this loss in an effort to improve motor responses other than verifying the stability of the construct and the extent of the decompression. Four patients developed postoperative deficits of radicular origin, three of them recovering fully at 3 months. No relation was found between intraoperative blood pressure, Hb changes, and Tc-MEP changes. Severity of Tc-MEP loss did not correlate with postoperative deficits. Shortening of more than 10 mm was linked to more severe Tc-MEP changes in the thoracic group.

CONCLUSIONS

Transcranial MEP changes during spinal shortening procedures are common and do not appear to predict severe postoperative deficits. Total loss of Tc-MEP (not witnessed in our series) might require a more drastic approach with possible reversal of the correction and wake-up test.