The risk of delayed spinal cord injury in pediatric spinal deformity surgery.

Delayed spinal cord injury (SCI) hours or days after surgery, with uneventful monitoring and initial normal postoperative neurological examination, is a rare complication. Based on anecdotal evidence, the risk of delayed spinal cord injury might be higher than previously assumed. Therefore the aim of this study was to determine the risk of delayed SCI after pediatric spinal deformity surgery between 2013-2019 in the Netherlands. The total number of pediatric spinal deformity surgeries performed for scoliosis or kyphosis between 2013-2019 was obtained from the Dutch National Registration of Hospital Care. All eleven Dutch hospitals that perform pediatric spinal deformity surgery were contacted for occurrence of delayed SCI. From the identified patients with delayed SCI, the following data were collected: patient characteristics, details about the SCI, the surgical procedure, management and degree of improvement.2884 pediatric deformity surgeries were identified between 2013-2019. Seven patients (0.24%) with delayed SCI were reported: 3 idiopathic, 2 neuromuscular (including 1 kypho-scoliosis) and 2 syndromic scoliosis. The risk of delayed SCI after pediatric deformity surgery was 1:595 in idiopathic scoliosis, 1:214 in syndromic scoliosis, 1:201 in neuromuscular scoliosis. All seven patients had a documented normal neurological examination in the first postoperative period; neurological deficits were first diagnosed at a median 16h (range 2.5-40) after surgery. The risk of delayed SCI after pediatric deformity surgery is higher than previously reported, especially in patients with non-idiopathic scoliosis. Regular postoperative testing for late neurologic deficit should be performed for timely diagnosis and management of this devastating complication.

Surgeon equipoise as an inclusion criterion for the evaluation of nonoperative versus operative treatment of thoracolumbar spinal injuries.

BACKGROUND CONTEXT: Prospective studies have failed to demonstrate the superiority of either operative or nonoperative treatment of thoracolumbar fractures. Similar to other surgical fields, research has been limited by the variability in surgical interventions, difficult recruitment, infrequent pathology, and the urgency of interventions. PURPOSE: To outline factors precluding randomized controlled trials in spinal fractures research, and describe a novel methodology that seeks to improve on the design of observational studies. STUDY DESIGN/SETTING: A preliminary report describing an observational study design with clinical equipoise as an inclusion criterion. The proposed methodology is a cohort study with head-to-head comparison of operative and nonoperative treatment regimens in an expertise-based trial fashion. Patients are selected retrospectively by an expert panel and clinical outcomes are assessed to compare competing treatment regimens. Surgeon equipoise served as an inclusion criterion. PATIENT SAMPLE: Patients with closed or open thoracolumbar spinal fracture with or without neurological impairment, presenting to one of two different trauma centers between 1991 and 2005 (N = 760). OUTCOME MEASURES: Homogeneity of baseline clinical and demographic data and distribution of prognostic risk factors between the operative and the nonoperative cohort. METHODS: Patients treated for spine fractures at two University hospitals practicing opposing methods of fracture intervention were identified by medical diagnosis code searches (n = 760). A panel of spine treatment experts, blinded to the treatment received clinically has assessed each case retrospectively. Patients were included in the study when there was disagreement on the preferred treatment, that is, operative or nonoperative treatment of the injury. Baseline and initial data of a study evaluating nonoperative versus operative spinal fracture treatment are presented. RESULTS: One hundred and ninety patients were included in the study accounting for a panel discordance rate of 29%. The distribution of baseline characteristics and demographics of the study populations were equal across the parallel cohorts enrolled in the study, that is, no differences in prognostic factors were observed. CONCLUSIONS: The use of clinical equipoise as an inclusion criterion in comparative studies may be used to avoid selection bias. Using multivariate analysis of retrospectively assembled parallel cohorts, a valid comparison of operative and nonoperative spine fracture treatment strategies and their outcomes is possible.

Scoliosis in Prader-Willi syndrome: prevalence, effects of age, gender, body mass index, lean body mass and genotype.

BACKGROUND: The reported prevalence of scoliosis in children with Prader-Willi syndrome varies from 15% to 86%. OBJECTIVE: To study the prevalence of scoliosis and the effects of age, gender, body mass index (BMI), total lean body mass (LBM), LBM of the trunk (trunkLBM) and genotype. DESIGN: Radiographs were taken, length and weight were measured (BMI standard deviation scores (BMI SDS) and body surface area (BSA)), and dual energy x-ray absorptiometry was performed, measuring LBM and trunkLBM. PATIENTS: 96 children, median (interquartile range) age 4.8 years (2.1 to 7.5), were included in a multicentre study. None received growth hormone treatment. MAIN OUTCOME MEASURES: Two types of scoliosis were identified: (1) long C-curve type scoliosis (LCS) and (2) idiopathic scoliosis (IS). Children were divided into age categories (infants, 0-3 years; juveniles, 3-10 years; adolescents, 10-16 years). RESULTS: The prevalence of scoliosis was 37.5% and increased with age (infants and juveniles, approximately 30%; adolescents, 80%); 44% of children with scoliosis had a Cobb angle above 20 degrees . Children with scoliosis were significantly older than those without. Children with LCS were younger and more hypotonic than those with IS: median (interquartile range) age 4.4 years (1.7-5.9) vs 11.1 years (6.5-12.1) (p = 0.002) and trunkLBM/BSA ratio 7080 (6745-7571) vs 7830 (6932-8157) (p = 0.043). CONCLUSIONS: The prevalence of scoliosis in children with Prader-Willi syndrome is high (37.5%). Many children with scoliosis (13%) had undergone brace treatment or surgery. The type of scoliosis is affected by age and trunkLBM/BSA ratio.

Spontaneous remodeling of the spinal canal after conservative management of thoracolumbar burst fractures.

STUDY DESIGN: Forty-two conservatively treated patients with a burst fracture of the thoracic, thoracolumbar, or lumbar spine with more than 25% stenosis of the spinal canal were reviewed more than 1 year after injury to investigate spontaneous remodeling of the spinal canal. OBJECTIVES: To investigate the natural development of the changes in the spinal canal after thoracolumbar burst fractures. SUMMARY OF THE BACKGROUND DATA: Surgical removal of bony fragments from the spinal canal may restore the shape of the spinal canal after burst fractures. However, it was reported that restoration of the spinal canal does not affect the extent of neurologic recovery. METHODS: Using computerized tomography, the authors compared the least sagittal diameter of the spinal canal at the time of injury with the least sagittal diameter at the follow-up examination. RESULTS: Remodeling and reconstitution of the spinal canal takes place within the first 12 months after injury. The mean percentage of the sagittal diameter of the spinal canal was 50% of the normal diameter (50% stenosis) at the time of the fracture and 75% of the normal diameter (25% stenosis) at the follow-up examination. The correlation was positive between the increase in the sagittal diameter of the spinal canal and the initial percentage stenosis. There was a negative correlation between the increase in the sagittal diameter of the spinal canal and age at time of injury. Remodeling of the spinal canal was not influenced by the presence of a neurologic deficit. CONCLUSION: Conservative management of thoracolumbar burst fractures is followed by a marked degree of spontaneous redevelopment of the deformed spinal canal. Therefore, this study provides a new argument in favor of the conservative management of thoracolumbar burst fractures.

Peroneus longus and tibialis anterior muscle activity in the stance phase. A quantified electromyographic study of 10 controls and 25 patients with chronic ankle instability.

The electromyographic activity of the peroneus longus and anterior tibial muscles of 25 patients with chronic ankle instability (18 patients with bilateral symptoms and 7 patients with unilateral complaints) and 10 controls was registered during the stance phase under different walking conditions. With balance secured by external support, there was a variable amount of peroneal activity, most of which was found in the third quarter of stance. A high increase in peroneus longus activity starting after foot-flat was found when subjects had to maintain balance in a natural way. No difference in peroneal activity was found in relation to instability complaints. It is thought that the peroneus longus serves to maintain balance, that this function decreases with increase of speed and that one cannot rely on this muscle to prevent an inversion injury during normal walking. The anterior tibial muscle was predominantly active in the first quarter after heel contact. An increase in activity in the second quarter as an effect of loss of secured balance suggests that this muscle plays some part in balance control, but this is not its main function. A significant increase in tibialis anterior activity was found in patients with bilateral instability. No significant difference was found between the symptomatic and asymptomatic leg of patients with unilateral instability under the same walking conditions. These findings suggest changes in central control.

Recurrent kyphosis after posterior stabilization of thoracolumbar fractures. 24 cases treated with a Dick internal fixator followed for 1.5-4 years.

24 patients with Th12-L1 fractures treated with a Dick internal fixator were analyzed to assess predictors of poor outcome. 4 patients had fixation without bone transplantation, 20 patients had a posterior fusion, and 12 of them had additional transpedicular spongioplasty. There were fractures of the transpedicular screws in 4 and screw migration in 2 cases. The increase in the local kyphosis angle was greater than the increase in the anterior compression angle and this did not correlate with spongioplasty or fusion. Fixation failure was in all cases related to a disproportionate increase in the local kyphosis angle. There was no difference between the patients with transpedicular spongioplasty and posterior fusion and the other patients with respect to results and complications. Bony collapse was not the major cause of failure and consequently there was no measureable contribution of transpedicular spongioplasty. We found that the Dick internal fixator for unstable fractures was associated with a higher complication rate than earlier reported.

CT scan prediction of neurological deficit in thoracolumbar burst fractures.

In 139 patients with burst fractures of the thoracic, thoracolumbar or lumbar spine, the least sagittal diameter of the spinal canal at the level of injury was measured by computerised tomography. By multiple logistic regression we investigated the joint correlation of the level of the burst fracture and the percentage of spinal canal stenosis with the probability of an associated neurological deficit. There was a very significant correlation between neurological deficit and the percentage of spinal canal stenosis; the higher the level of injury the greater was the probability. The severity of neurological deficit could not be predicted.

Homosexual and heterosexual partner preference in ovariectomized female rats: effects of testosterone, estradiol and mating experience.

Ovariectomized female rats, longterm treated with estradiol benzoate (EB, 20 micrograms, 3 x/week) or testosterone propionate (TP, 0.4 mg, 3 X/week), were tested for homo- or heterosexual partner preference behavior with either tethered animals (sexually active male vs. estrous female) or animals behind a wire mesh. A preference score was calculated by subtracting the time spent in the vicinity of the stimulus female from the time spent in the vicinity of the stimulus male. Thus, a positive score indicates preference for the male (heterosexual preference), a negative score preference for the female (homosexual preference). Two weeks of EB treatment caused a clearcut preference for the male incentive. This heterosexual preference was significantly different from the indistinct preference of the TP-treated females. Sexual interaction with a freely moving active male (with or without a vaginal mask which prevented intromissions) did not alter the preference for the male of the EB-treated females. It did affect, however, the preference behavior of the TP-treated females significantly: it changed in the direction of the sexually active estrous incentive female, i.e., a homosexual preference. This change in preference could not be attributed to the experience of penile intromissions, it occurred despite the presence of a vaginal mask. Apparently, being mounted by a sexually active male had a negative reinforcing value in the TP-treated female rats and provoked a homosexual partner preference.