Does Combining Drilling and Curettage to Percutaneous Trans-epiphyseal Screws Improve Correction of Limb Length Discrepancy? A Comparative Study.

Objectives: Physeal drilling and curettage (PDC) and percutaneous epiphysiodesis using transphyseal screws (PETS) are among the most widely used techniques to treat leg-length discrepancy (LLD). This study compared the efficacy and outcomes between PETS alone and PETS combined with PDC (PETS + PDC). Methods: Retrospective study of children who underwent epiphysiodesis of the proximal tibia or distal femur with either PETS or PETS + PDC between 2008 and 2018 at a single institution. Radiographic parameters and complications were reviewed at completion of treatment and most recent follow-up. Results: A total of 23 epiphysiodeses in 15 patients, average age 13.1 years, with either PETS (13 femur/tibias) or PETS + PDC (10 femur/tibias) were included. PETS patients were treated for a longer time (median: 24 months vs 11 months, p = 0.004), however, follow-up time was similar between groups (p = 0.577), on average 2.7 years. In the PETS group, LLD decreased from 2.55 to 0.84 cm at most recent follow-up (p = 0.010), and in the PETS + PDC group from 3.01 to 1.2 cm (p = 0.005), achieving a correction of 1.71 cm for PETS and 1.83 cm for PETS + PDC (p = 0.871). A correction of LLD to ≤ 2 cm was achieved in 8 PETS (89%) and 4 PETS + PDC cases (67%) (p = 0.525). Two PETS patients (22%) and 1 PETS + PDC (17%) patient returned to the OR for further correction due to persistent LLD (p = 1.000). No differences existed in total number of complications, angular deformity or return to physical activity between groups (p ≥ 0.05 for each comparison). Conclusions: This study showed equal efficiency in resolving LLD between the PETS and PETS + PDC procedures with minimal operative complications.Level of Evidence III.

The Effect of Guided Growth Surgery on Langenskiold Stage and Mechanical Axis in Early-Onset Blount Disease: A Retrospective Case Series.

INTRODUCTION: Our understanding of the efficacy of guided growth surgery with tension-band plating (TBP) in early-onset Blount disease is evolving. Preliminary work has demonstrated that TBP can normalize the mechanical axis, yet its effect on Langenskiöld stage (LS) has not previously been reported. The primary outcome of this study was improvement in LS after TBP. Secondary outcomes were improvement in LS at most recent follow-up and improvement in mechanical axis deviation (MAD), mechanical medial proximal tibial angle, and mechanical lateral distal femoral angle at treatment completion and most recent follow-up. METHODS: A retrospective review was done of patients with early-onset Blount disease treated with TBP between January 1, 2010, and December 31, 2019, across two institutions. Inclusion criteria were a radiographic diagnosis of early-onset Blount disease (LS changes present), surgery with TBP, and follow-up beyond implant removal. Radiographs before surgery, at removal of hardware (ROH), and at most recent follow-up were evaluated. RESULTS: Twenty-five limbs in 16 children who underwent TBP at a mean age of 5.8 ± 2.3 years were included. Implants were in situ a mean of 1.9 ± 0.7 years. The mean follow-up after ROH was 3.6 ± 1.4 years. LS ranged from 1 to 5 preoperatively with 14 of 25 limbs (56%) staged ≥3. LS improved in 15 of 25 limbs (60%) at ROH and in 21 of 25 limbs (84%) at most recent follow-up. Langenskiöld changes resolved in 7 of 25 limbs (28%) at most recent follow-up. Preoperatively, the MAD was varus in all limbs, but at ROH, the MAD had improved in 22 of 23 limbs with neutral or valgus alignment in 20 of 23 limbs (87%). At most recent follow-up, 16 of 23 limbs (70%) maintained improved alignment. DISCUSSION: There was improvement/resolution of LS and varus deformity in early-onset Blount disease in most patients who underwent TBP. Based on these results, TBP for early-onset Blount disease should be the first-line surgical treatment. LEVEL OF EVIDENCE: IV.

The Impact of Standardized Recovery Pathways on Language Barriers and Inpatient Pain Management.

BACKGROUND AND OBJECTIVES: Inpatient postoperative care is reliant upon clear, open communication between providers and patient-families, and thus is particularly vulnerable to disparities when discordant languages exist. It is not yet understood how standardized postoperative protocols may mitigate disparities related to language discordance. METHODS: This is a retrospective cohort study among adolescent idiopathic scoliosis patients who underwent posterior spinal fusion at a tertiary care children's hospital in Bronx, New York after implementation of a postoperative pathway in 2017. Outcomes reliant upon communication between patient-families and providers were measured, including measures of pain management (number and type of pain medications requested, daily pain assessments, total opioids consumed), as well as outpatient pain scores. RESULTS: A total of 160 patients were included (39 language other than English [LOE]). Between patient cohorts, there were no significant differences in demographic or operative characteristics. On univariate analyses, LOE patients were more likely to be given a basal dosing of patient-controlled analgesia or additional boluses (26% vs 12%, P = .03), consumed 0.53 fewer benzodiazepine medications per day (P = .01), and were more likely to have pain at outpatient follow-up (67% vs 43%, P = .03). On multivariate analyses, LOE patients were more likely to be placed on basally dosed or receive additional boluses of patient-controlled analgesia (odds ratio 3.19, 95% confidence interval 1.15-8.85). CONCLUSIONS: As standardized pathways become more common in health care, it is critical to monitor for components of these protocols that may be vulnerable to language-related disparities, such as therapies reliant on symptom description and outpatient follow-up.

Pediatric Fractures: Does Vitamin D Play a Role?

BACKGROUND: Vitamin D (25-OHD) deficiency and insufficiency are reported in about half of all children. The literature on low 25-OHD and pediatric fracture risk presents inconsistent results. This study evaluates the association between pediatric fractures and 25-OHD, parathyroid hormone (PTH), and calcium. METHODS: This is a prospective case-control study in 2 urban pediatric emergency departments (2014-2017). Patients aged 1 to 17 requiring intravenous access were enrolled. Demographics, nutrition, and activity information were recorded and levels of 25-OHD, calcium, and PTH were measured. RESULTS: Two hundred forty-five subjects were enrolled: 123 fractures and 122 controls. Overall, the mean 25-OHD level was 23 ng/mL±8.5: 52 (21%) of patients were 25-OHD sufficient; 193 (79%) were not. Ninety-six percent of patients with lower extremity fractures had low 25-OHD versus 77% of patients with upper extremity fractures ( P =0.024). The fracture cohort was younger ( P =0.002), included more males ( P =0.020), and spent more time playing outdoor sports ( P =0.011) than the control cohort. The 25-OHD level (fracture 22.8 ng/mL±7.6 vs. nonfracture 23.5 ng/mL±9.3, P =0.494) and median calcium level (fracture 9.8 mg/dL vs. nonfracture 10.0 mg/dL, P =0.054) were similar between cohorts. The median PTH level was higher in the fracture than the control cohort (33 vs. 24.5 pg/mL; P <0.0005); PTH was elevated to hyperparathyroidism (>65 pg/mL) in 13% of fractures and 2% of controls ( P =0.006). Matched subgroup analysis of 81 fracture patients and 81 controls by age, gender, and race showed that PTH was the only variable independently associated with increased odds of fracture (odds ratio=1.10, 95% CI, 1.01-1.19, P =0.021) in a model adjusted for vitamin D sufficiency and time spent playing outdoor sports. CONCLUSIONS: Low 25-OHD is common in children with fractures but we found no difference in 25-OHD levels between fracture and nonfracture cohorts. This research can impact evidence-based guidelines on vitamin D level screening and/or supplementation after fracture. LEVEL OF EVIDENCE: Diagnostic level IV-case-control study.

Percutaneous epiphysiodesis using transphyseal screws (PETS) versus tension-band plating (TBP): comparative study of outcomes for correcting limb length discrepancy.

OBJECTIVES: The best effective treatment strategy for limb length discrepancy (LLD) is still being debated. The goal of this study was to compare the efficacy and results of tension-band plating (TBP) and percutaneous epiphysiodesis using transphyseal screws (PETS) for LLD correction. METHODS: From June 2008 to January 2019, children who had lower extremity epiphysiodesis with either TBP or PETS were reviewed retrospectively. At the conclusion of treatment, LLD, angular deformity, and complications were reviewed. The t-test or Wilcoxon rank sum test was used to compare continuous variables. Categorical variables were evaluated using Fisher's exact test or χ2 test. RESULTS: A total of 32 epiphysiodeses with TBP (14 patients, 24 femur/tibias) or PETS (13 patients, 23 femur/tibias) were compared. TBPs were conducted while the patients were younger (11.0 vs. 13.1 years, p = 0.005). The treatment durations were similar in both groups (TBP: 23.5 months vs. PETS: 24 months, p = 0.132). PETS had significantly shorter operative time (p = 0.047), length of hospital stay (p = 0.014), and time to return to full activity (p = 0.043). LLD in the TBP group reduced from 2.64 to 1.38 cm (p = 0.005), while in the PETS group it decreased from 2.76 to 1.08 cm (p = 0.001). During treatment, the rate of LLD correction was 0.49 ± 0.9 cm/year for limbs treated with TBP and 1.0 ± 1.1 cm/year for limbs treated with PETS (p = 0.185). At the end of treatment, 8 TBP cases (47%) and 9 PETS cases (60%) had achieved LLD ≤ 2 cm (p = 0.502), and at the most recent follow-up, this had grown to 11 (65%) in the TBP group and 12 (80%) in the PETS group. There were no significant differences in the total number of complications between groups (p > 0.05). Revision surgery was required in 11 TBP and 3 PETS limbs due to persistent LLD or angular deformity (AD) (p = 0.016). Logistic regression did not reveal any significant association between TBP and the rate of complication or revision surgery. CONCLUSION: PETS and TBP are both effective methods for limb length equalization. PETS, on the other hand, was linked to a shorter operative time, a shorter hospital stay, a faster recovery to pre-operative function, and a lower complication rate. The rate of revision surgery due to persistent LLD or AD was higher in TBP. We advise surgeons against utilizing TBP to correct LLD. LEVEL OF EVIDENCE: III.

Pre-operative prone radiographs can reliably determine spinal curve flexibility in adolescent idiopathic scoliosis (AIS).

PURPOSE: The purpose of this study was to evaluate the correlation between non-effort prone and bending radiographs in determining curve flexibility in adolescent idiopathic scoliosis (AIS). METHODS: A retrospective review of AIS patients who underwent pre-operative full spine radiographic imaging from 2006 to 2019 was performed. The Cobb angle (CA) of proximal thoracic (PT), main thoracic (MT) and thoracolumbar/lumbar (TL/L) curves were measured and correlated on standing, prone and bending radiographs. Standing, bending, and prone measurements were correlated using Spearman's analysis, and intra-rater reliability was evaluated using intraclass correlation analysis. RESULTS: A total of 381 patients (74% female) with a mean age of 15.1 ± 2.5 years were identified. A strong correlation existed between the prone and bending CA for the PT (rs = 0.797, p < 0.01) and MT (rs = 0.779, p < 0.01) curve and a moderate correlation existed between the prone and bending TL/L curve (rs = 0.641, p < 0.01). For a non-structural PT curve, a prone CA < 25° correctly identified a bending CA < 25° 96.7% of the time (p < 0.005). For a non-structural MT curve, a prone CA < 35° correctly identified a bending CA < 25° 90.2% of the time (p < 0.005). For a non-structural TL/L curve, a prone CA < 35° correctly identified a bending CA < 25° 95% of the time (p < 0.005). CONCLUSION: Prone radiographs demonstrated a moderate to strong correlation with bending radiographs and may be used as a proxy for determining spinal flexibility, especially when bending films are deemed unreliable. LEVEL OF EVIDENCE: III.

Sagittal spinopelvic changes after posterior spinal fusion in adolescent idiopathic scoliosis.

PURPOSE: This article examines if longer posterior spinal fusions with instrumentation (PSFI) into the lumbar spine (L3/4) alter spinopelvic parameters compared with selective fusions to T12/L1/L2 in adolescent idiopathic scoliosis (AIS) patients. METHODS: We analysed radiographs of 84 AIS patients, 58 (69%) females and 26 (31%) males, who underwent PSFI at an mean age of 15 years ± 2.5 years, range 10 years to 21 years, between 1st January 2007 and 31st December 2014. Radiographic parameters were measured pre- and post-operatively at most recent follow-up (range 2 years to 8.2 years): pelvic incidence (PI), lumbar lordosis (LL, L1-S1 and L4-S1), sagittal vertical alignment (SVA), scoliosis angle and proximal junctional kyphosis (PJK). PI-LL was calculated. Data was analysed using t-tests or Wilcoxon rank-sum tests. RESULTS: In total, 32 patients underwent a selective fusion with lowest instrumented vertebra (LIV) T12-L2, and 52 patients underwent a fusion with LIV L3-L4. In both groups, scoliosis angle was significantly corrected at follow-up (p < 0.005).Pre-operatively, both groups had similar LL (L1-S1) and PI-LL. Post-operatively, LL increased in the L3-4 fusion group (p < 0.005) but did not change in the selective fusion group (p = 0.116). This change in LL in the L3-4 fusion group affected the post-operative PI-LL (T12-L2 fusion -4.9° versus L3-4 fusion -13.6°, p = 0.002). No differences were seen in PI, SVA or LL L4-S1 between groups. Radiographic PJK occurred in seven of the L3-4 patients with and without PJK (noPJK -8.8° versus PJK -25.8°, p = 0.026). CONCLUSIONS: In patients who underwent a fusion ending at L3 or L4, LL was increased. This altered the PI-LL relationship, and appeared to increase the risk of PJK. LEVEL OF EVIDENCE: III.

What's New in Pediatric Limb Lengthening and Deformity Correction?

Over the past 5 years, published literature regarding treatment of pediatric limb deformity and limb length discrepancy demonstrates much interest in better understanding, categorizing and treating these challenging problems. Many studies explore expanding and refining indications for traditional treatment methods like guided growth techniques. Other studies have evaluated the results of new techniques such as lengthening via mechanized intramedullary nails. Additionally, series comparing older and newer techniques such as lengthening with external devices versus mechanized nails are becoming increasingly available.

Parental understanding of intoeing gait - A preliminary study.

OBJECTIVE: Evaluation of a child's intoeing gait is one of the most common referrals made to a pediatric orthopedist. Families may have difficulty understanding the often transient and usually benign nature of intoeing. The purpose of this study was to investigate parental perceptions of an intoeing gait both before and after consultation with an orthopedic practitioner. METHODS: 48 parents of children referred to pediatric orthopedic surgeons for evaluation of intoeing gait completed a 22-item questionnaire that assessed demographics, anxiety, and parental perceptions of intoeing. Questionnaires were administered before and after visits. Statistical analysis was performed using Wilcoxon signed-rank tests and Fisher exact tests. RESULTS: Before their visits, parents reported similar levels of anxiety and understanding regarding intoeing, independent of their age or education. After the visits, anxiety decreased (P < 0.001), and understanding increased (P < 0.001) although younger parents (18-25 years) reported higher post-visit anxiety compared to parents older than 25 (P = 0.014). Similarly, parents with a high school degree or less reported higher post-visit anxiety compared to parents who attended college (P = 0.009). Post-visit understanding was inversely correlated with post-visit anxiety (r = -0.717; P < 0.001). Additionally, parents who reported high anxiety post-visit stated they were more likely to seek additional care (P < 0.001). CONCLUSIONS: Younger parents with lower education levels were more likely to leave visits with high anxiety and poor understanding. These parents were more likely to consider seeking further treatment for their child's intoeing, placing additional stress on their child, themselves and an overburdened healthcare system.

Ultrasound elastography of the patellar tendon in young, asymptomatic sedentary and moderately active individuals.

BACKGROUND: The recent use of ultrasound elastography to study patellar tendon softness has demonstrated increased tendon softness in high-level athletes. We hypothesized that measurable alterations in patellar tendon softness may be present in young asymptomatic subjects engaging in moderate levels of physical activity. METHODS: This was a cross-sectional study. Gray-scale ultrasound and ultrasound elastography of the right and left patellar tendons were performed in young asymptomatic sedentary subjects and moderately active subjects who engaged in at least 30 min of physical activity 4-5 times weekly. The distribution of soft, intermediate and stiff tissue within each tendon was analyzed. Tendon softness was correlated with subject age, gender and level of athletic activity. RESULTS: Sixty patellar tendons in 30 subjects were evaluated (18 males, 12 females, mean age 22.5 years). Seventeen subjects were defined as "active" and 13 as "sedentary." All tendons had a normal gray-scale sonographic appearance. Tendon softness was significantly higher in active subjects (P = 0.01) and decreased with age (P = 0.04). In sedentary individuals there was no significant correlation between age and tendon softness (P = 0.404). Similarly, gender showed no correlation with tendon softness (P > 0.05). CONCLUSIONS: Patellar tendon softness is higher in young subjects and in those engaging in moderate physical activity. This may reflect an adaptation to increased tendon load. Tendon softness in active subjects decreases with age, while it remains at a constant value in sedentary individuals. LEVEL OF EVIDENCE: Level 3.

A National Analysis on Predictors of Discharge to Rehabilitation After Corrective Surgery for Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Retrospective study of a national database. OBJECTIVE: To identify the incidence and risk factors for discharge to a rehabilitation facility after corrective surgery for adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: The vast majority of patients who undergo surgery for AIS are discharged home, with limited data on rates and causes for discharge to a rehabilitation facility. METHODS: The United States National Inpatient Sample (NIS) database was queried for the years 2012 to 2014. Inclusion criteria were children aged 10 to 18 who underwent surgery for idiopathic scoliosis. Studied data included patient demographics, operative parameters, length of stay, and hospital charges. Perioperative complications were also examined, along with their association with discharge to an inpatient rehabilitation facility. Statistical analysis was performed via chi-squared testing and multivariate analysis, with significance defined as a P-value <0.05. RESULTS: A total of 17,275 patients were included (76.3% female, mean age 14 yr). Out of the entire cohort, 4.8% of patients developed a complication and 0.6% were discharged to a rehabilitation facility. The most common complications included respiratory failure (2.3%), reintubation (0.8%), and postoperative hematoma (0.8%). Following multivariate analysis, male sex (Odds ratio (OR) 4.7; 95% Confidence Interval (CI), 1.8-12.2; P = 0.002), revision surgery (OR 29.6; 95% CI, 5.7-153.5; P < 0.001), and development of a perioperative complication (OR 12.3; 95% CI, 4.7-32.4; P < 0.001) were found to be significant predictors of discharge to rehabilitation. Average length of stay was 8 ±â€Š6 versus 5 ±â€Š3 days and hospital charges were $254,425 versus $186,273 in the complication and control groups, respectively (both P < 0.001). CONCLUSION: Discharge to rehabilitation after AIS surgery is uncommon. However, patients who are male, undergo revision procedures, or develop a complication may have a higher risk of a non-routine discharge. Complication occurrence also resulted in significantly longer lengths of stay and healthcare costs. LEVEL OF EVIDENCE: 3.

Effect of body mass index on surgical outcomes after posterior spinal fusion for adolescent idiopathic scoliosis.

OBJECTIVE Obesity is an increasing public health concern in the pediatric population. The purpose of this investigation was to examine the impact of body mass index (BMI) on 30-day outcomes after posterior spinal fusion for adolescent idiopathic scoliosis (AIS). METHODS The American College of Surgeons National Surgical Quality Improvement Program Pediatric database (2013 and 2014) was reviewed. Patients 10-18 years of age who had undergone fusion of 7 or more spinal levels for AIS were included. Thirty-day outcomes (complications, readmissions, and reoperations) were compared based on patient BMI per age- and sex-adjusted growth charts as follows: normal weight (NW; BMI < 85th percentile), overweight (OW; BMI 85th-95th percentile), and obese (OB; BMI > 95th percentile). RESULTS Patients eligible for study numbered 2712 (80.1% female and 19.9% male) and had a mean age of 14.4 ± 1.8 years. Average BMI for the entire cohort was 21.9 ± 5.0 kg/m2; 2010 patients (74.1%) were classified as NW, 345 (12.7%) as OW, and 357 (13.2%) as OB. The overall complication rate was 1.3% (36/2712). For NW and OW patients, the complication rate was 0.9% in each group; for OB patients, the rate was 4.2% (p < 0.001). The 30-day readmission rate was 2.0% (55/2712) for all patients, 1.6% for NW patients, 1.2% for OW patients, and 5.0% for OB patients (p < 0.001). The 30-day reoperation rate was 1.4% (39/2712). Based on BMI, this reoperation rate corresponded to 0.9%, 1.2%, and 4.8% for NW, OW, and OB patients, respectively (p < 0.001). After controlling for patient age, number of spinal levels fused, and operative/anesthesia time on multiple logistic regression analysis, obesity remained a significant risk factor for complications (OR 4.61), readmissions (OR 3.16), and reoperations (OR 5.33; all p < 0.001). CONCLUSIONS Body mass index may be significantly associated with short-term outcomes after long-segment fusion procedures for AIS. Although NW and OW patients may have similar 30-day outcomes, OB patients had significantly higher wound complication, readmission, and reoperation rates and longer hospital stays than the NW patients. The findings of this study may help spine surgeons and patients in terms of preoperative risk stratification and perioperative expectations.

Complications associated with surgical repair of syndromic scoliosis.

BACKGROUND: There are a number of syndromes that have historically been associated with scoliosis e.g.: Marfan, Down, and Neurofibromatosis. These syndromes have been grouped together as one etiology of scoliosis, known as syndromic scoliosis. While multiple studies indicate that these patients are at high risk for perioperative complications, there is a paucity of literature regarding the collective complication rates and surgical needs of this population. METHODS: PubMed and Embase databases were searched for literature encompassing the surgical complications associated with the surgical management of patients undergoing correction of scoliosis in the syndromic scoliosis population. Following exclusion criteria, 24 articles were analyzed for data regarding these complications. RESULTS: The collective complication rates and findings of these articles were categorized based on specific syndrome. The rates and types of complications for each syndrome and the special needs of patients with each syndrome are discussed. Several complication trends of note were observed, including but not limited to the universally nearly high rate of wound infections (>5% in each group), high rate of pulmonary complications in patients with Rett syndrome (29.2%), high rate (>10%) of dural tears in Marfan and Ehlers-Danlos syndrome patients, high rate (>20%) of implant failure in Down and Prader-Willi syndrome patients, and high rate (>25%) of pseudarthrosis in Down and Ehlers-Danlos patients. CONCLUSIONS: Though these syndromes have been classically grouped together under the umbrella term "syndromic," there may be specific needs for patients with each of these ailments. Given the high rate of complications, further research is necessary to understand the unique needs for each of these patient groups in the preoperative, intraoperative, and postoperative settings.

Juvenile osteochondritis dissecans of the knee: current concepts in diagnosis and management.

Osteochondritis dissecans of the knee is a diagnosis that encompasses a wide spectrum of pathologies that can result in irreversible damage to articular cartilage and subchondral bone. Osteochondritis dissecans was first described more than 100 years ago, and despite substantial research on the topic, large gaps remain in the understanding of its etiology and optimal treatment. An underlying vascular insult, resulting in separation of the progeny lesion from the parent subchondral bone, is a suspected cause but remains unproven. No single standardized classification exists to accurately predict long-term risk. Nonsurgical treatment with activity modification remains an option for stable lesions in young patients. Surgical treatment to encourage vascular ingrowth and healing is gaining popularity and represents a shift in thinking regarding the risk of disease progression. Unstable and displaced lesions remain a difficult treatment challenge. Various salvage procedures have shown promise, but the potential for long-term morbidity remains.

Creation of rabbit bone and soft tissue tumor using cultured VX2 cells.

BACKGROUND: To create rabbit VX2 bone tumors, it is surgically less demanding to implant VX2 cell suspensions than minced tumor fragments. A VX2 cell line that can be expanded using standard cell culture techniques might provide an unlimited supply of cells needed to create these bone tumors. Therefore, the aim of the present study was to establish a VX2 cell line and verify its tumorigenicity in an athymic mouse and rabbit animal model. MATERIALS AND METHODS: Minced VX2 tumor fragments were allowed to grow as a monolayer in 10 mL Dulbecco's modified Eagle medium/nutrient mixture F-12 (1:1) supplemented with 10% fetal calf serum and passaged multiple times. The tumorigenecity of the cultured VX2 cells were tested in athymic mice (intradermal tumor development) and in New Zealand white rabbits (bone and soft tissue tumor model). RESULTS: The VX2 cells proliferated rapidly in tissue culture flasks containing Dulbecco's modified Eagle medium/nutrient mixture F-12 medium supplemented with 10% fetal bovine serum. After reaching confluence, the VX2 cells can only be subcultured when plated at a greater density (e.g., at a dilution of 1:1). All 6 athymic mice developed tumors within 15 d of VX2 cell suspension implantation. In the rabbits, the VX2 cells were able to produce tumors in muscle tissue and in the distal femurs but not in the proximal tibia. CONCLUSIONS: VX2 cell lines can be successfully created from VX2 tumor fragments and passaged multiple times. In contrast to previous reports, the VX2 cells grown in vitro are capable of maintaining their tumorigenecity. However, successful tumor growth might depend on the initial number of cells implanted and the use of extracellular matrices for tumor proliferation.

Evaluation of elution and mechanical properties of two injectable chemotherapeutic bone cements.

Chemotherapeutic bone cements can both stabilize the bone fractures as well as deliver chemotherapy agents directly to the bone metastatic site and adjacent soft tissue tumors. This study evaluated the in vitro elution and flexural properties of Vertebroplastic™ and Confidence Ultra™ bone cements (Depuy Spine Inc., Raynham, Mass., USA) containing methotrexate. In vitro elution was measured by placing bone cement specimens containing 4 different methotrexate amounts in 20 ml saline, and the methotrexate elution was measured at regular intervals for 672 h. The flexural properties of bone cement containing 2 different initial methotrexate amounts after storage in physiological saline were measured using a 3-point bending test. The drug elution rate depended on the initial methotrexate amount added and the type of bone cement used. The relationship between the initial drug amount added and the drug elution rate was not linear. Methotrexate elution decreased the flexural modulus and strength of specimens; this decrease was not proportional to the initial amount of methotrexate added. The results show that bone cements are well suited for use with chemotherapy agents. However, the elution and mechanical properties of each bone cement-drug amount combination should be thoroughly quantified in vitro before using such a combination in a clinical setting.

The role of the vertical expandable titanium rib in the treatment of infantile idiopathic scoliosis: early results from a single institution.

OBJECTIVES: Few studies exist on the management of progressive curves in the setting of infantile idiopathic scoliosis. We have performed a retrospective review of our experience treating those patients unresponsive to conservative management with the vertical expandable prosthetic titanium rib. METHODS: We reviewed 8 consecutive patients with infantile idiopathic scoliosis treated at our institution between 2000 and 2009. All patients were screened to ensure that no confounding congenital anomalies or comorbidities contributed to the spinal deformity. Pretreatment, posttreatment, and most recent Cobb angle, sagittal balance, and spinal length, were measured to assess overall curve correction. Patient charts were reviewed for the occurrence of complications. RESULTS: The average age at the time of surgery was 45.8 months (range: 24 to 84 mo). The average preoperative Cobb angle was 84 degrees (range: 50 to 119 degrees) and showed mean curve correction of 35.1% (range: 20% to 60%) over an average follow-up of 32 months (range: 14 to 45 mo). Spinal height increased a mean of 71 mm (range: 51 to 98 mm) over an average of 4 lengthenings (range: 2 to 7). Three of the patients (37%) experienced minor hardware complications, none experienced a neurologic deficit. CONCLUSIONS: Our results suggest that the vertical expandable prosthetic titanium rib device is a safe and effective treatment option for large-magnitude curves in this unique patient population. LEVEL OF EVIDENCE: IV--case series.