Acute onset of central diabetes insipidus during adolescent idiopathic scoliosis surgery.

This is a case report of a 12-year-old female with idiopathic scoliosis undergoing posterior scoliosis reconstruction that developed an acute onset of central diabetes insipidus (CDI) during surgery. The diagnosis was made as a result of an intraoperative increase in urine output to 6.82 ml/kg/hour (550 ml), a serum sodium increase from 139 to 147 mmol/L, a serum osmolality of 299 mOsmol/kg, a rapid response to vasopressin administration and a low vasopressin level of < 0.5 picograms/ml (normal, 1-5 picograms/ml). This is the first reported case of CDI with a documented low vasopressin level that has occurred in a pediatric scoliosis surgical patient.

Neurophysiological monitoring of spinal cord function during spinal deformity surgery: 2020 SRS neuromonitoring information statement.

The Scoliosis Research Society has developed an updated information statement on intraoperative neurophysiological monitoring of spinal cord function during spinal deformity surgery. The statement reviews the risks of spinal cord compromise associated with spinal deformity surgery; the statement then discusses the various modalities that are available to monitor the spinal cord, including somatosensory-evoked potentials, motor-evoked potentials, and electromyographic (EMG) options. Anesthesia considerations, the importance of a thoughtful team approach to successful monitoring, and the utility of checklists are also discussed. Finally, the statement expresses the opinion that utilization of intraoperative neurophysiological spinal cord monitoring in spinal deformity surgery is the standard of care when the spinal cord is at risk.

Early pelvic fixation failure in neuromuscular scoliosis.

BACKGROUND: To report on early failures of pelvic fixation in posterior spinal fusions for neuromuscular scoliosis. METHODS: A retrospective review of posterior-only spinal instrumentation and fusion to the pelvis with iliac screws was performed. Forty-one patients with a mean age of 14 years and mean 16 levels fused met the inclusion criteria. Diagnoses include cerebral palsy (22), Duchenne muscular dystrophy (7), other neuromuscular (10), and spina bifida (2). Cox proportional hazards regression modeling was used to compare rates of failure. RESULTS: The mean preoperative primary Cobb angle was 82 degrees (range, 21 to 144 degrees). The pelvic obliquity correction was 76%. The fixation in the pelvis failed in 12/41 patients (29%). Failures include: screw head disengaged from screw shaft (5), iliac screw disengaged from rod (2), iliac connector disengaged from rod (2), iliac connector disengaged from iliac screw (4), and iliac screw loosened from bone (3). No failures occurred if there were at least 6 screws in L5, S1, and pelvis (0/7 patients). The failure rate with <6 screws in L5, S1, and pelvis was higher at 35% (12/34 patients) (P=0.16). When using traditional iliac screws with connectors to rods, all constructs had <6 screws in L5, S1, and pelvis. Only 1 failure occurred when S2-iliac screws were used, but was without clinical consequence. The mean time from surgery to failure was 18 months (range, 1 to 49 mo). CONCLUSION: Not placing bilateral pedicle screws at L5 and S1, in addition to 2 iliac screws, was associated with a 35% early failure rate of pelvic fixation. LEVEL OF EVIDENCE: Level IV.

Spinal Deformity in Russell-Silver Syndrome.

STUDY DESIGN: Cross-sectional analysis. OBJECTIVES: To evaluate the prevalence of scoliosis and kyphosis in patients with Russell-Silver syndrome (RSS). SUMMARY OF BACKGROUND DATA: Russell-Silver syndrome was described by Silver and Russell in the 1950s and 1960s and is characterized by body asymmetry and other growth abnormalities. To the authors' knowledge, this is the first study to evaluate the prevalence of scoliosis and kyphosis in patients with Russell Silver Syndrome. METHODS: The authors performed a cross-sectional analysis of 163 persons, identified through a national RSS foundation, who consented to be included in the study and responded to a general survey questionnaire. Subjects who reported a diagnosis of scoliosis and/or kyphosis were subsequently asked to submit copies of prior spinal radiographs for evaluation at the authors' center. For evaluation of scoliosis and kyphosis on the radiographs, the researchers reviewed posteroanterior and lateral standing radiographs to measure coronal and sagittal Cobb angles. RESULTS: Of 163 respondents, 24 (14%) reported scoliosis, 5 (3.1%) reported kyphosis, and 6 (3.8%) reported both kyphosis and scoliosis, with average age of diagnosis of 8 years (range, 1-43 years). Of these respondents, 6 reported a history of bracing for scoliosis and/or kyphosis and 3 braced respondents reported having had surgery for scoliosis and/or kyphosis. An additional 3 respondents reported that corrective spinal surgery was "planned for the future." CONCLUSIONS: Persons with RSS have a high prevalence of spinal deformity (21%) and a significant number of these patients will undergo corrective surgery (6 of 34; 18%).

Nutritional improvement following growing rod surgery in children with early onset scoliosis.

PURPOSE: We aimed to evaluate the nutritional status of children with early onset scoliosis (EOS) and to determine if treatment with growing rod instrumentation improves weight percentile. METHODS: Data was retrospectively collected on 88 EOS patients treated with growing rods at six institutions. Mean age at surgery was 5.8 years, and mean Cobb angle was 75°. All patients were followed for at least 2 years (mean 4 years). Weights were converted to normative percentiles based on the patients' age and gender. RESULTS: Preoperatively, 47 % (41/88) of patients were <5 percentile for weight, thus failing to thrive. There was a significant increase in mean postoperative weight percentiles at latest follow-up (p = 0.004). 49 % of patients gained weight, with a mean of 18 percentile. A significant relationship exists between age at initial surgery and percentile weight gain (p < 0.005), with children <4 years old not demonstrating postoperative improvement. This relationship was not confounded by preoperative weight, preoperative Cobb angle, or years of follow-up (p > 0.05). Children with neuromuscular and syndromic diagnoses do not appear to improve their mean nutritional status after surgery when compared to patients with idiopathic or congenital/structural scoliosis (p = 0.006). CONCLUSION: Following growing rod treatment, there was significant improvement in nutritional status in approximately 50 % of patients, similar to that reported with VEPTR. Neuromuscular and syndromic patients did not experience nutritional improvement post-operatively. These findings support the theory that growing rods improve the clinical status of EOS patients, as nutritional improvement is one outcome of improved clinical status. The relationship between age at initial surgery and nutritional improvement is intriguing.

The Use of Pedicle Screws in Children 10 Years of Age and Younger With Growing Rods.

STUDY DESIGN: Retrospective review of a multicenter database. OBJECTIVES: To evaluate the incidence of implant-related complications of pedicle screws versus hooks in children with early-onset scoliosis treated with growing rods. SUMMARY OF BACKGROUND DATA: Because growing rods have a high rate of implant complications compared with spinal fusion, this challenging, fusionless group of patients is a provocative environment in which to evaluate implant-related complications of pedicle screws. METHODS: A total of 159 patients with growing rods treated at 18 institutions were included. Inclusion criteria were children aged less than 10 years who had growing rod surgery between 1998 and 2008 with minimum 2-year follow-up from index surgery. Charts and radiographs were evaluated only for complications directly related to a pedicle screw or hook. The researchers evaluated 464 pedicle screws and 643 hooks. RESULTS: Of the 464 pedicle screws, there were 17 complications (3.7%) directly related to screws: acute loss of fixation (2), migration (14), and breakage (1). Of the 643 hooks, there were 47 complications (7.3%): acute loss of fixation (28), migration (16), and unspecified loss of fixation (3). When loss of fixation occurred, the mean time to loss of fixation was similar for both implants: 33 months for hooks and 30 months for screws (p = .95). There were no complications involving neurologic or vascular injury directly related to a hook or screw. CONCLUSIONS: Pedicle screws in growing rod constructs had fewer implant-related complications than hooks in patients with early-onset scoliosis in a minimum 2-year follow-up period (p = .02). It is encouraging that there were no neurological or vascular injuries associated with either implant in 159 children with over 4.5 years of mean follow-up, in a provocative, fusionless environment.

Are Rib Versus Spine Anchors Protective Against Breakage of Growing Rods?

STUDY DESIGN: Retrospective multicenter, case-control study. OBJECTIVE: To compare the risks of rod breakage and anchor complications between distraction-based growing rods with proximal spine versus rib anchors. SUMMARY OF BACKGROUND DATA: Rod breakage is a known complication of distraction-based growing rod instrumentation. METHODS: A total of 176 patients met inclusion criteria: minimum 2-year follow-up, younger than age 9 years at index surgery, non-Vertical Expandable Prosthetic Titanium Rib distraction-based growing rods, and known anchor locations. Mean follow-up was 56 months (range, 24-152 months). Survival analyses using Cox proportional hazards model (accounting for varying lengths of follow-up) of rod breakage, anchor complications, preoperative Cobb angle, number of growing rods, age, and number of levels instrumented were performed using a significance level of p < .05. RESULTS: Thirty-four patients had rib-anchored growing rods and 142 had spine-anchored growing rods. This analysis found that proximal rib-anchored growing rods have a 23% risk of lifetime rod breakage compared with spine-anchored growing rods (6% vs. 29%) (p = .041) without a significant increase in risk of anchor complications (38% vs. 33%) (p = .117). The number of implanted rods (p = .839), age (p = .649), and number of instrumented levels (p = .447) were not statistically significant regarding rod breakage risk, although higher preoperative Cobb angles were significant (p = .014). CONCLUSIONS: Preoperative Cobb angle appears to be the most influential factor in determining whether growing rods break (p = .014). Univariate analysis found that rib anchors were associated with less than one-fourth the risk of rod breakage than spine anchors (p = .04) but multivariate analysis found no significant association between anchors and rod breakage (p = .07). This trend suggests that rib-anchored growing rod systems may be associated with less rod breakage because the system is less rigid as a result of some "slop" at the hook-rib interface, as well as the normal motion of the costovertebral joint.

Neuromonitoring Changes Are Common and Reversible With Temporary Internal Distraction for Severe Scoliosis.

STUDY DESIGN: Retrospective review of consecutive cases. OBJECTIVE: To examine the neurologic implications of applying intraoperative distraction to large curves. SUMMARY OF BACKGROUND DATA: Temporary rods provide internal distraction during correction of severe scoliosis and may be an alternative to prolonged halo traction or vertebral column resection. METHODS: A single surgeon's consecutive experience with posterior-only spinal fusion with temporary distraction rods was reviewed retrospectively. Inclusion criteria were long posterior-only spinal fusion (10 or more levels) for severe scoliosis (major Cobb angle 80° or greater), treated with temporary internal distraction. Records were reviewed for age, gender, diagnosis, intraoperative course, and complications. Radiographs were reviewed for Cobb angles, T1-S1 length, and space available for each lung. RESULTS: Twenty-two patients with a mean age of 14 years and a mean of 15 levels fused (range, 10-18 levels) were included. The mean preoperative coronal Cobb angle was 113° (range, 83°-144°), and a mean correction of 62° (54%) was achieved. There was a mean T1-S1 increase of 8.4 cm (range, 2.4-14 cm). Nine patients had 2-stage procedures separated by a mean of 7 days. Thirteen patients had a single procedure. Of 22 patients, 9 (41%) had intraoperative neuromonitoring changes. All neuromonitoring changes were reversed after releasing distraction on the temporary rod, except in 1 case. No patient had a clinical neurologic deficit. CONCLUSIONS: Use of temporary distraction rods for severe scoliosis produces curve correction while providing a mean increase in T1-S1 height of 8 cm. Most steps in this surgery are reversible. Neuromonitoring changes are common, but they are reversible with release of some distraction. Neuromonitoring changes did not affect the final magnitude of correction, and there were no clinical neurologic deficits. We recommend that this procedure be performed only with good neuromonitoring.

Simple steps to minimize spine infections in adolescent idiopathic scoliosis.

BACKGROUND: To examine the surgical site infection (SSI) rates in patients undergoing posterior spinal fusion surgery for adolescent idiopathic scoliosis (AIS) after implementation of a change in antibiotic prophylaxis and intraoperative irrigation. METHODS: A retrospective review of all consecutive spinal fusions for AIS from 1996 to 2008 was performed. In 2003, 2 changes in our protocol were implemented: (1) routine antibiotic prophylaxis was changed from cefazolin alone to vancomycin and ceftazidime; (2) intraoperative irrigation technique was changed from bulb syringe to pulse lavage irrigation. We compared the rates of deep SSI requiring irrigation and debridement before institution of these changes (1996 to 2002) to the rates after these changes (2003 to 2008). RESULTS: Before the change in the antibiotic and lavage regimen, 261 spinal fusions were performed. Of these, 28/261 (11%) patients underwent irrigation and debridement for SSI. The most common infecting pathogen was coagulase-negative Staphylococcus aureus (47%). Between the years 2003 and 2008, 263 spinal fusions were performed. Only 2/263 (0.7%) patients underwent irrigation and debridement for SSI. This decrease in infection rate is highly significant (P<0.001). CONCLUSIONS: Routine use of vancomycin and ceftazidime and pulsatile lavage for posterior spinal fusion in AIS patients decreased the rates of postoperative infection by 10 fold. As 2 variables were changed, it is impossible to know the relative effect of each. However, as spine infections can be so devastating, and the potential risks of these changes are small, we recommend both the new antibiotic and irrigation protocol. LEVEL OF EVIDENCE: Level III.

A classification of growth friendly spine implants.

BACKGROUND: Various types of spinal implants have been used with the objective of minimizing spinal deformities while maximizing the spine and thoracic growth in a growing child with a spinal deformity. PURPOSE: The aim of this study was to describe a classification system of growth friendly spinal implants to allow researchers and clinicians to have a common language and facilitate comparative studies. Growth friendly spinal implant systems fall into 3 categories based upon the forces of correction the implants exert on the spine, which are as follows: Distraction-based systems correct spinal deformities by mechanically applying a distractive force across a deformed segment with anchors at the top and bottom of the implants, which commonly attach to the spine, rib, and/or the pelvis. The present examples of distraction-based implants are spine-based or rib-based growing rods, vertical expandable titanium rib prosthesis, and remotely expandable devices. Compression-based systems correct spinal deformities with a compressive force applied to the convexity of the curve causing convex growth inhibition. This compressive force may be generated both mechanically at the time of implantation, as well as over time resulting from longitudinal growth of vertebral endplates hindered by the spinal implants. Examples of compression-based systems are vertebral staples and tethers. Guided growth systems correct spinal deformity by anchoring multiple vertebrae (usually including the apical vertebrae) to rods with mechanical forces including translation at the time of the initial implant. The majority of the anchors are not rigidly attached to the rods, thus permitting longitudinal growth over time as the anchors slide over the rods. Examples of guided growth systems include the Luque trolley and Shilla. CONCLUSIONS: Each system has its benefits and shortcomings. Knowledge of the fundamental principles upon which these systems are based may aid the clinician to choose an appropriate treatment for patients. Having a common language for these systems may aid in comparative research. Vertical expandable titanium rib prosthesis is used with humanitarian exemption. The other devices mentioned in this manuscript are not approved for growing constructs by the Food and Drug Administration and are used off-label.

Ten percent of patients with adolescent idiopathic scoliosis have variations in the number of thoracic or lumbar vertebrae.

BACKGROUND: Surveys have demonstrated that wrong-site surgery of the spine is performed by up to 50% of spine surgeons over the course of a career. Inaccurate identification of appropriate vertebral levels is a common reason for wrong-site spine surgery. The present study examined the prevalence of variations in the number of vertebrae in patients with adolescent idiopathic scoliosis. METHODS: A retrospective review of radiographs and reports of 364 consecutive patients undergoing operative treatment for adolescent idiopathic scoliosis at a single center was performed. The study included eighty-eight male patients (24%) and 276 female patients (76%) with a mean age of fourteen years (range, ten to twenty years). Radiographs were reviewed to assess the number of thoracic and lumbar vertebrae and the presence of a lumbosacral transitional vertebra. RESULTS: Ten percent of the patients (thirty-eight) had an atypical number of vertebrae in the thoracic and/or lumbar spine. Twenty-one patients (5.8%) had an atypical number of thoracic vertebrae, with fourteen having eleven thoracic vertebrae and seven patients having thirteen. Twenty-four patients (6.6%) had an atypical number of lumbar vertebrae, with four having four lumbar vertebrae and twenty patients having six. A lumbosacral transitional vertebra was present in 6.3% (twenty-three) of the patients. Multilevel vertebral anomalies were present in 1.9% of the patients (seven of 364). A variation in the number of vertebrae had been identified in 0.5% (two) of the reports by the radiologist. CONCLUSIONS: Variations in the number of thoracic or lumbar vertebrae were found in 10% of patients with adolescent idiopathic scoliosis but had been identified in only 0.5% of the radiology reports.

Intensive care unit versus hospital floor: a comparative study of postoperative management of patients with adolescent idiopathic scoliosis.

BACKGROUND: Patients undergoing posterior spinal instrumentation and fusion surgery for adolescent idiopathic scoliosis were admitted to the intensive care unit until two years ago, at which time we changed our protocol to admit these patients to the general hospital floor following a brief stay in a postanesthesia care unit. This study compared postoperative management on a hospital floor with that in the intensive care unit for patients with adolescent idiopathic scoliosis undergoing posterior spinal fusion. METHODS: A retrospective review of 124 consecutive patients with adolescent idiopathic scoliosis treated with spinal fusion from August 2007 to August 2010 was performed. Inclusion criteria were a diagnosis of adolescent idiopathic scoliosis and posterior spinal instrumentation and fusion surgery. RESULTS: Of 124 patients, sixty-six were managed postoperatively in the intensive care unit and fifty-eight, on the hospital floor. The mean age at the time of surgery was fourteen years. A mean of eleven vertebral levels (range, six to fifteen levels) were fused. No significant difference between the groups was found with respect to the mean age at the time of surgery, mean weight, mean preoperative and postoperative Cobb angles, and mean number of levels fused (p ≥ 0.12). However, the use of analgesic and antianxiety medication, number of postoperative blood tests, days of hospital stay, and number of physical therapy sessions were significantly decreased in the floor group compared with the intensive care unit group (p ≤ 0.05). No patient from the floor group had to be admitted to the intensive care unit. The mean charge was $33,121 for the floor group and $39,252 for the intensive care unit group (p < 0.001). CONCLUSIONS: Initial postoperative management of patients with adolescent idiopathic scoliosis following a posterior spinal instrumentation and fusion surgery on a general hospital floor, rather than in an intensive care unit, was associated with a shorter hospital stay, fewer blood tests, less analgesic and antianxiety medication usage, and fewer physical therapy sessions at this high-volume, academic, tertiary-care children's hospital. In addition to improved patient outcomes, there was a significant decrease of 16% in hospital charges for the group that did not go to the intensive care unit.

Improvement of Kyphoscoliosis in a 9-Year-Old Using Growth Modulation With a Posterior Tether: A Case Report.

OBJECTIVE: Our aim was to report the first case of a posterior tether used for growth modulation in the treatment of spinal deformity. METHODS: A 9-year-old boy with progressive kyphoscoliosis failed multiple attempts of brace treatment; the deformity progressed to kyphosis of 73° and scoliosis of 41° on standing radiographs. We placed a posterior tether using hydroxyapatite-coated pedicle screws with a flexible polymer cord under modest compression unilaterally from T3 to T11 with no subperiosteal dissection and no attempt at fusion. RESULTS: Immediately postoperatively, the kyphosis improved from 73° to 65° and the scoliosis from 41° to 26°. At 26 months postoperatively, the kyphosis improved to 42° and the scoliosis to 26°. At 31 months postoperatively, distal junctional kyphosis developed. The patient then underwent a spine fusion at age 11 years. We noted at surgery that the previously tethered spine from T3 to T11 was fused with no motion present even after implants were removed. CONCLUSION: A posterior unilateral tether was successful at progressively improving kyphosis and preventing worsening of scoliosis in a 9-year-old boy, but it led to fusion of the spine within 31 months.

Some Connectors in Distraction-based Growing Rods Fail More Than Others.

STUDY DESIGN: Retrospective review of a prospectively collected patient cohort. OBJECTIVES: This study examined the rate of failure of various types of spinal rod connectors in distraction-based growing rod constructs for early-onset scoliosis. SUMMARY OF BACKGROUND DATA: Distraction-based growing rods have a high rate of reported complications. METHODS: We performed a retrospective review of a single surgeon's consecutive cases with growing rod constructs for early-onset scoliosis. Connector failure was defined as loosening of the connector-rod interface, which resulted in shortening of the construct and loss of distractive force. We included 30 patients with average age of 5 years (range, 1-10 years) with diagnoses of congenital scoliosis (15), neuromuscular (10), idiopathic (4), and other (1). Minimum follow-up was 2 years, with a mean follow-up of 49 months (range, 24-83 months). RESULTS: Of 98 connectors, there were 12 connector failures (12.2%) in 9 patients. In all failures, the set screw loosened, resulting in rod slippage. On average, failures occurred 25.5 months after the index procedure, and after the third lengthening. Simple side-to-side closed connectors with circular slots had the highest rate of slippage (7 of 17; 41%). Side-to-side connectors with V-groove slots that mechanically lock the rod had 10 times fewer failures, (1 of 27; 4%) (p = .006). Only 1 of 34 longitudinal connectors failed (3%) (p = .002). The average T1-S1 gain during growth was 6.5 mm/year for patients with a connector failure and 9.0 mm/year for those who did not (p = .25). Connectors failed in dual rods (6 of 18; 33%) and single rods (6 of 15; 40%) at similar rates (p = .97). CONCLUSIONS: Connector failure in distraction-based growing rods is associated with 28% less T1-S1 gain. Side-to-side connectors with circular slots had a failure rate of 41% compared with side-to-side connectors with V-groove slots (4%). Longitudinal connectors had a failure rate of 4%.

Upper thoracic pedicle screw loss of fixation causing spinal cord injury: a review of the literature and multicenter case series.

STUDY DESIGN: Case Series and Review of the Literature. OBJECTIVE: To report on cases of spinal cord injury from loss of fixation of upper thoracic pedicle screws. SUMMARY OF BACKGROUND DATA: Despite generally low rates of intraoperative neurological injury from pedicle screws, there is 1 reported case of T2 pedicle screw pullout causing spinal cord injury. METHODS: A review of the literature and an informal poll of 2 professional societies searching for cases in which thoracic pedicle screws migrated postoperatively into the spinal canal was performed. RESULTS: Three patients had failure of spinal instrumentation with the most cephalad pedicle screws (T2, T4 and T4) plowing into the spinal canal, causing direct trauma to the spinal cord with resulting clinical and neurological injury. Failure of fixation occurred at 1 month, 1 year, and 2 years after index procedure. In 2 patients, neurological injury was severe enough that they became nonambulatory; the third patient had rapidly progressive leg weakness. In each case, there were only 1 or 2 pedicle screws at the top of the construct, and a span of 6 to 7 vertebrae without rigid fixation below this. One similar case was found in the literature. CONCLUSIONS: Spinal instrumentation with only 1 to 2 pedicle screws at the top of the construct, and a span of >5 vertebrae below these screws without rigid fixation may be at risk for implant failure and catastrophic spinal cord injury. In the rare instance in which only 1 to 2 pedicle screws can be placed at the cephalad half of long spinal constructs, one may consider using hooks that would fail posteriorly and may present less risk to the spinal cord.

Ewing sarcoma of the tibia mimicking fibrous dysplasia.

Ewing sarcoma (ES) family of tumors is the second most common primary bone malignancy in children. It usually presents as an aggressive looking lesion often located in the meta-diaphyseal region of long bones, with bone destruction, permeation, cortical thinning and/or destruction, periosteal reaction, and large soft-tissue mass. The purpose of this study is to illustrate the occurrence of a fibrous dysplasia (FD)-appearing ES of the tibia. These cases underscore the potential difficulties encountered in the diagnosis of ES. In this study, we performed a retrospective review of children who presented with an otherwise benign-appearing lesion of the tibia, suggestive of FD, which proved to be ES after biopsy. As a result, all patients presented with a history of indolent lower extremity pain of several months of duration, without significant swelling or constitutional symptoms. Plain films revealed an otherwise benign-appearing/FD-like lesion without bone destruction and mild cortical thinning, little or no periosteal reaction. Magnetic resonance imaging revealed the intramedullary extension of the lesion without significant cortical or periosteal involvement and no soft tissue mass. Lesions were hypointense on T1-weighted imaging and hyperintense on T2-weighted imaging. All patients underwent open incisional biopsy and after cytogenetic and molecular studies, the diagnosis of ES was confirmed. We conclude that ES is a deadly malignant tumor if left untreated or if mismanaged. Although it usually presents as an aggressive-looking lesion, at times it may mimic FD and has a benign-looking appearance, making the diagnosis unlikely and challenging. Summation of these cases demonstrates that the potential reasons for misdiagnoses include a low level of suspicion, an atypical site occurrence, a benign radiographic appearance, and a lack of or insufficient histologic specimens.

Clay-shoveler's fracture equivalent in children.

STUDY DESIGN: Case report and literature review. OBJECTIVE: This article reports 2 cases of clay-shoveler's fracture equivalent in children presenting acutely after participation in sports. SUMMARY OF BACKGROUND DATA: The clay-shoveler's fracture in adults is an avulsion fracture of the lower cervical or upper thoracic spinous process. To our knowledge, this is the first report in English literature on soft-tissue avulsion injury of the spinous process in children presenting with history and symptoms similar to clay-shoveler's fractures. METHODS: Retrospective review of 2 cases. RESULTS: A 14-year-old baseball player and a 16-year-old wrestler experienced acute posterior neck pain after participation in sports. Both patients presented with a history and physical examination suggestive of clay-shoveler's fracture but showed no evidence of injury on radiographs. Subsequent magnetic resonance images demonstrated an acute soft-tissue avulsion of the spinous process at C7 in 1 patient and T2 in the other. With nonoperative therapy, both patients returned to sports by 4 months, with occasional, intermittent discomfort a year after injury, which did not limit any activities. CONCLUSION: In adolescents, if the history and physical examination are consistent with a clay-shoveler's fracture, but radiographs are normal, magnetic resonance imaging may be indicated to diagnose a soft-tissue avulsion.

Spondylolysis is frequently missed by MRI in adolescents with back pain.

PURPOSE: Magnetic resonance imaging (MRI) is often used in the evaluation of lower back pain in adolescents. The purpose of our study is to report on the frequency of MRI missing spondylolysis in adolescents with back pain in a pediatric orthopaedic practice. METHODS: A retrospective review of all patients with a diagnosis of spondylolysis who presented from January 2000 to March 2010 was performed. All patients were evaluated at a single institution by the senior author. Inclusion criteria were patients with spondylolysis confirmed on computed tomography (CT) or plain film that also received an MRI. RESULTS: Eleven patients with spondylolysis had an MRI performed. The mean age of the study patients was 14.2 years (range 10-17). The diagnosis of spondylolysis was missed in the MRI radiology reading in 7 out of 11 (64 %) studies. CONCLUSIONS: MRI missed a spondylolysis in over half of the adolescents in this consecutive series. In patients with a history or physical findings suggestive of spondylolysis, such as localized pain of the lumbar spine with back extension, further radiographic evaluation should be considered, even if an MRI is negative. LEVEL OF EVIDENCE: III, retrospective review.

Comparison of the post-transcriptional regulation of the mRNAs for the surface proteins PSA (GP46) and MSP (GP63) of Leishmania chagasi.

MSP (GP63) and PSA (GP46) are abundant 63- and 46-kDa glycolipid-anchored proteins on the surface of the promastigote form of most Leishmania species. MSP is a zinc metalloprotease that confers resistance to host complement-mediated lysis. PSA contains internal repeats of 24 amino acids, and its function is unknown. The steady state levels of mRNAs for both glycoproteins are regulated post-transcriptionally, resulting in about a 30-fold increase as Leishmania chagasi promastigotes grow in vitro from logarithmic phase to stationary phase. Previous studies showed the 3'-untranslated regions (3'-UTRs) of these mRNAs are essential for this post-transcriptional regulation. These two 3'-UTRs of 1.0 and 1.3 kilobases were cloned immediately downstream of a beta-galactosidase reporter gene in a plasmid, and segments were systematically deleted to examine which portions of the 3'-UTRs contribute to the post-transcriptional regulation. The 92-nucleotide segment of greatest similarity between the two 3'-UTRs was deleted without loss of regulation, but the segments flanking this similarity region have positive regulatory elements essential for the regulation. We propose that similar, but non-identical, molecular mechanisms regulate the parallel expression of these two L. chagasi mRNAs despite their lack of sequence identity. These post-transcriptional mechanisms resemble the mechanism recently suggested for the regulation of mRNAs encoding the dipeptide (EP) and pentapeptide (GPEET) repeat proteins in Trypanosoma brucei that involves interactions between positive and negative regulatory elements in the 3'-UTR.