Intraobserver and Interobserver Measurement Variability of the Rib-Vertebral Angle Difference.

BACKGROUND: The rib-vertebral angle (RVAD) differentiates between progressive and resolving infantile idiopathic scoliosis (IIS) curves. Those with a RVAD<20 degrees often resolve without treatment, whereas those >20 degrees often progress and require treatment. The mathematical magnitude of RVAD measurement variability has not been described, and was thus the purpose of this study. It is important to know the reliability of RVAD measurements so as to understand changes that can be attributed to observer error alone. PURPOSE: The purpose of the study was to mathematically determine the intraobserver and interobserver measurement variability of the RVAD difference in IIS. METHODS: A convenience sample of 50 patients with IIS was selected. The RVAD was measured twice by 7 different observers separated by a minimum of 3 weeks. The 7 different readers chosen to measure the RVAD were 2 orthopaedic residents, 1 pediatric radiologist, and 4 attending pediatric orthopaedic surgeons. The same goniometer was used for all measurements. Intraobserver and interobserver measurement variability was determined using 3 well known used statistical methods. RESULTS: The 3 different methods used to determine intraobserver and interobserver variability using 95% prediction/confidence limits gave very similar results. Intraobserver variability was ∼24 degrees and the interobserver variability was ∼23 degrees. DISCUSSION: The utility of the RVAD in medical decision-making and counseling of patients with IIS should be approached with caution when used in isolation due to the large measurement variability. LEVEL OF EVIDENCE: Level 3.

Operative Intervention of Supracondylar Humerus Fractures More Complicated in July: Analysis of the July Effect.

BACKGROUND: The "July Effect" involves the influx of new interns and residents early in the academic year (July and August), which may have greater potential for poorer patient outcomes. Current orthopaedic literature does not demonstrate the validity of this concept in arthroplasty, spine, hand, and arthroscopy. No study has investigated the possibility of this effect on common pediatric orthopaedic procedures, such as closed reduction and percutaneous pin fixation of supracondylar humerus fractures. METHODS: A retrospective review of all type II or III supracondylar humerus fractures that underwent primary closed reduction and percutaneous pin fixation (CPT code 24538) at a single pediatric level 1 trauma center from July 2009 to June 2013. Patients were grouped according to time in the academic year: early (July and August) and late (May and June). Demographic data included length of follow-up, age at surgery, sex, side of injury, and Wilkin's modified Gartland classification. Outcomes included length of operation, number of pins used, length of stay, complications, and the need for repeat surgery. RESULTS: There were 245 patients, 101 in the early and 144 in the late group. There was no increase in surgical time [33.32±24.74 (early) vs. 28.63±10.06 (late) min, P=0.07) or complication rates [7.0% (early) vs. 2.1% (late), P=0.06) between the early and the late groups. Cases performed with junior residents demonstrated longer operative (31.72±17.07 vs. 28.96±18.71 min, P=0.02) and fluoroscopy (48.63±30.96 vs. 34.12±27.38 s, P=0.01) times. CONCLUSIONS: The academic orthopaedic surgeon must ensure the education of residents, while providing the highest level of safety to patients. Our study shows that education of young residents early in the academic year results in no increase in operative times, radiation exposure, or complications. LEVEL OF EVIDENCE: Level III.

The Effect of Growing Rod Treatment on Hemoglobin and Hematocrit Levels in Early-onset Scoliosis.

BACKGROUND: This study examines preoperative hemoglobin (Hgb) and hematocrit (Hct) levels in a group of early-onset scoliosis (EOS) patients and the effect of distraction-based growing rods (GRs) on these levels. Children with EOS are at risk for respiratory insufficiency and chronic hypoxemia. Increased Hgb and Hct levels have been identified as surrogate markers for chronic hypoxemia. A study of patients who underwent VEPTR surgery showed a significant decrease in Hgb levels following surgery. METHODS: Data were retrospectively collected on 66 EOS patients without confounding respiratory issues or oxygen dependence who were treated with GRs at 5 institutions. Average age at initial surgery was 5.5 years. Patients were followed for a minimum of 2 years (average 3.7 y). Preoperative and postoperative Hgb and Hct levels were converted to Z-scores based on age-adjusted mean blood indices and were compared using a paired t test. RESULTS: The prevalence of elevated Hgb and Hct levels (Z-score >2) preoperatively was 15% (10/66) and 19% (12/64), respectively. The average Hgb Z-score decreased from 0.20 to -0.31 (P=0.005) 6 to 24 months following surgery and the Hct Z-score decreased from 0.31 to -0.28 (P=0.002) 6 to 24 months following surgery. CONCLUSIONS: Following distraction-based GR treatment of children with EOS there was a significant decrease in both their Hgb and Hct. This is a physiological marker of decreased hypoxemia and improved pulmonary function. LEVEL OF EVIDENCE: Level III-therapeutic study.

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.

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.

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.

Perioperative ketorolac use in children undergoing lower extremity osteotomies.

BACKGROUND: Ketorolac has previously been shown to afford good pain relief in children undergoing surgery. Due to concerns about potential complications, particularly nonunion, delayed union, and excessive blood loss, ketorolac use has been limited in pediatric orthopaedics. The goal of this study is to examine complications associated with the perioperative use of ketorolac in children undergoing lower extremity osteotomies. METHODS: A retrospective review was conducted of 327 consecutive children undergoing osteotomy surgery who had a minimum of 6 months follow-up. Of the 327 patients, 299 patients (625 osteotomies) had received ketorolac perioperatively and 28 (57 osteotomies) had not. RESULTS: There was no significant difference in the rate of either osseous or soft tissue complications between the 2 groups. There were no nonunions in either of the groups. Delayed union occurred in 5 of 682 osteotomies (0.7%), including 0.6% in the ketorolac group (4/625 osteotomies), and 1.8% (1/57 osteotomies) in the nonketorolac group (P=0.893). Wound complications occurred in 16/327 patients overall (4.9%), including 13/299 (4.3%) in the ketorolac group and 3/28 (10.7%) in the nonketorolac group (P=0.301). There was no significant difference in estimated blood loss (EBL) (P=0.584) or the need for blood transfusion (P=0.777) between the 2 groups. Of the 19 occasions when blood was transfused perioperatively in the ketorolac group, 15 patients had undergone unilateral (3 patients) or bilateral (12 patients) varus derotational osteotomy as part of their surgery. Overall, 15 of 113 patients (13.3%) in the ketorolac group who underwent unilateral or bilateral varus derotational osteotomy required blood transfusion, with rates of 31.8% (7/22) in those who had undergone concomitant pelvic osteotomy(ies) and 8.7% (8/91) in those who had not. CONCLUSIONS: The results of this study support the safety of perioperative ketorolac use in children undergoing lower extremity osteotomies. LEVEL OF EVIDENCE: Level III.

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.

Complications of ketorolac use in children undergoing operative fracture care.

BACKGROUND: Ketorolac is commonly used for pain relief perioperatively, but its safety is questioned in children undergoing orthopaedic surgery. The aims of this study are to evaluate the rates of osseous and soft tissue complications after operative pediatric fracture care in children treated with ketorolac, and to compare the rates to those in children treated without ketorolac. METHODS: A retrospective review was conducted for 221 consecutive children who underwent operative fracture care by a single surgeon and were followed until fracture healing. Of the 221 children, 169 had received ketorolac perioperatively and 52 had not received. The children were evaluated for potential complications associated with the perioperative parenteral administration of ketorolac, specifically including nonunion, delayed union, need for transfusion, wound complications and infection. RESULTS: There was no difference in overall complication rates between the 2 groups (P=0.928). There were 3 cases in which blood transfusion was needed, 2/169 (1.2%) in the ketorolac group and 1/52 (1.9%) in the nonketorolac group. The wound infection was comparable in the 2 groups, occurring in 1/52 (1.9%) patients in the nonketorolac group and in 4/169 (2.3%) patients in the ketorolac group. There were no cases of delayed union or nonunion in either group. CONCLUSIONS: The results of this study indicate that perioperative ketorolac use does not increase the risk of complications after operative fracture care in children (P=0.928). Specifically, there was no increased risk with regard to infection or wound complications, and there were no cases of delayed union or nonunion. LEVEL OF EVIDENCE: Level III.

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.

Methadone-based Multimodal Analgesia Provides the Best-in-class Acute Surgical Pain Control and Functional Outcomes With Lower Opioid Use Following Major Posterior Fusion Surgery in Adolescents With Idiopathic Scoliosis.

INTRODUCTION: Posterior spinal fusion for idiopathic scoliosis is extremely painful, with no superior single analgesic modality. We introduced a methadone-based multimodal analgesia protocol, aiming to decrease the length of hospital stay (LOS), improve pain control, and decrease the need for additional opioids. METHODS: We analyzed 122 idiopathic scoliosis patients with posterior instrumented spinal fusion. They were matched by age, sex, surgeon, and the number of levels fused before and after the implementation of the new protocol. This analysis included 61 controls (intrathecal morphine, gabapentin, intravenous opioids, and adjuncts) and 61 patients on the new protocol (scheduled methadone, methocarbamol, ketorolac/ibuprofen, acetaminophen, and oxycodone with intravenous opioids as needed). The primary outcome was LOS. Secondary outcomes included pain scores, total opioid use (morphine milligram equivalents), time to a first bowel movement, and postdischarge phone calls. RESULTS: New protocol patients were discharged earlier (median LOS, 2 days) compared with control patients (3 days; P < 0.001). Total inpatient morphine consumption was lower in the protocol group (P < 0.001). Pain scores were higher in the protocol group on the day of surgery, similar on postoperative day (POD) 1, and lower by POD 2 (P = 0.01). The new protocol also reduced the median time to first bowel movement (P < 0.001), and the number of postdischarge pain-related phone calls (P < 0.006). CONCLUSION: Methadone-based multimodal analgesia resulted in significantly lower LOS compared with the conventional regimen. It also provided improved pain control, reduced total opioid consumption, and early bowel movement compared with the control group.

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%).

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.

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.

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%.

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.

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.