Does the external remote controller's reading correspond to the actual lengthening in magnetic-controlled growing rods?

PURPOSE: Magnetic-controlled growing rods (MCGRs) are now routinely used in many centres to treat early-onset scoliosis (EOS). MCGR lengthening is done non-invasively by the external remote controller (ERC). Our experience suggests that there may be a discrepancy between the reported rod lengthening on the ERC and the actual rod lengthening. The aim of this study was to investigate this discrepancy. METHODS: This was a prospective series. Eleven patients who were already undergoing treatment for EOS using MCGRs were included in this study. RESULTS: One hundred and ninety-two sets of ultrasound readings were obtained (96 episodes of rod lengthening on dual-rod constructs) and compared to their ERC readings. Only 15/192 (7.8%) readings were accurate; 27 readings (14.9%) were false positive; and 8 readings (4.2%) were an underestimation while 142 readings (74.0%) were an overestimation by the ERC. Average over-reporting by the ERC was 5.31 times of the actual/ultrasound reading. When comparing interval radiographs with lengthening obtained on ultrasound, there was a discrepancy with an average overestimation of 1.35 times with ultrasound in our series. There was a significant difference between ERC and USS (p = 0.01) and ERC and XR (p = 0.001). However, there was no significant difference between USS and XR (p > 0.99). CONCLUSION: The reading on the ERC does not equate to the actual rod lengthening. The authors would recommend that clinicians using the MCGR for the treatment of early-onset scoliosis include pre- and post-extension imaging (radiographs or ultrasound) to confirm extension lengths at each outpatient extension. In centres with ultrasound facilities, we would suggest that patients should have ultrasound to monitor each lengthening after distraction but also 6-month radiographs. These slides can be retrieved under Electronic Supplementary Material.

Do magnetic growing rods have lower complication rates compared with conventional growing rods?

BACKGROUND CONTEXT: The main advantage cited for the use of the magnetic controlled growing rod (MCGR) system over the conventional growing rod (CGR) in early-onset scoliosis is avoiding repeated invasive surgical procedures for lengthening, thus reducing, complications. PURPOSE: The study aimed to evaluate the complications of the MCGR system against the CGR system in our center. STUDY DESIGN/SETTING: This is a retrospective case control series. PATIENT SAMPLE: The sample includes patients with early-onset scoliosis treated with MCGR or CGR. OUTCOME MEASURES: Complications and unplanned return to theater were the outcome measures. RESULTS: Of the 37 patients (MCGR, N=10; CGR, N=27) in our cohort, 28 patients (76%) had at least one complication. Taking into account the follow-up period, MCGR had a higher complication rate than CGR group (0.32 complication per patient per year vs. 0.15 complication per patient per year). The use of MCGR was associated with a lower risk of deep infection (odds ratio [OR]: 0.22; p=.22) and superficial infection (OR: 0.07, p=.017) but increased risk of metalwork problems (OR: 4.67; p=.045) and unplanned return to theater (OR: 2.92; p=.05) compared with CGR. CONCLUSIONS: Although MCGR has a lower rate of both deep and superficial infections when compared with CGR, it does not completely avoid repeated invasive surgical procedures as previously suggested. It does have a significant increased risk of metalwork problems and unplanned return to theater.

Magnetic controlled growing rods for early-onset scoliosis: a 4-year follow-up.

BACKGROUND CONTEXT: There have been no studies with medium-term follow-up of magnetic controlled growing rods (MCGRs). PURPOSE: This study aimed to report our single center experience of a magnetic growing rod system with an average of 4 years' follow-up. STUDY DESIGN/SETTING: A retrospective case series was carried out. PATIENT SAMPLE: The sample comprised patients with early-onset scoliosis treated with magnetic controlled growth rods who were operated in 2011. OUTCOME MEASURES: Cobb angle, spinal growth rate, complications, and revision were the outcome measures. METHODS: Clinical case notes and radiographs were reviewed. RESULTS: There were 8 patients (5 dual-rod construct, 3 single-rod construct) who had a minimum of 44 months' follow-up and average of 48 months (44-55 months). Mean age at surgery was 8.2 years (range 3-10). Mean preoperative Cobb angle was 60° (34-94), whereas mean postoperative Cobb angle was 42° (32-63). The average number of extensions was 13.8 (range: 12-20). There were 6 patients (75%) who required 8 revision surgeries: rod problems (N=4), proximal screw pull-out (N=3), and development of proximal junction kyphosis (N=1). All three patients who had single-rod construct underwent revision procedure. Currently, four patients (50%) still have the magnetic rods in situ. The mean duration of MCGR in the patient in the removed group was 39 months (range: 34-46). CONCLUSIONS: Medium-term results of MCGR are not as promising as previously reported early results. Hence, MCGRs should be used with caution. Single-rod constructs should definitely be avoided. The role of MCGRs in revision cases still remains unknown.

Transsacral screw fixation for high-grade spondylolisthesis.

BACKGROUND CONTEXT: Symptomatic high-grade spondylolisthesis (Meyerding III-V) is usually treated by surgery. Recent literature shows that in situ fusion is better than reduction of the slip and fusion in high-grade spondylolisthesis. Furthermore, the outcome is improved if circumferential fusion is performed in severe spondylolisthesis. We have performed a new technique of circumferential fusion in high-grade spondylolisthesis using two transsacral hollow modular anchorage (HMA) screws supplemented with pedicle screw fixation and posterolateral fusion. PURPOSE: The aim of the study is to analyze the results of circumferential fusion using transsacral HMA screws supplemented with posterolateral fusion and pedicle screw fixation. STUDY DESIGN: Retrospective study. PATIENT SAMPLE: Twelve patients with high-grade spondylolisthesis were reviewed. OUTCOME MEASURES: Outcome was measured using short form 36 (SF-36) and the ability to return to work at the most recent follow-up. METHODS: All patients had interbody fusion using transsacral HMA screws filled with cancellous bone graft and supplemented with pedicle screw instrumentation and posterolateral fusion. RESULTS: The male to female ratio was 2:1 with a mean age of 31 years (range 13-54 years). Eleven of 12 patients had disappearance of leg pain. There were no neurological complications in any of them. Circumferential fusion was achieved in all of them at a mean follow-up of 21 months. The average physical function score improved from 22.50+/-10.34 to 57.50+/-17.39 (p=.001, 95% confidence interval [CI] -44.48 to -25.52), whereas the average pain score improved from 22.22+/-13.40 to 61.11+/-15.35 (p=.001, 95% CI -51.12 to -26.66). CONCLUSIONS: HMA screws avoid the complications associated with autologous cortical fibular strut graft and also are useful to promote interbody fusion, as the hollowness in the screw can be filled with cancellous bone graft that helps in better fusion. Supplementary pedicle screw fixation is necessary to protect the HMA screws, and they together give a stable construct that can achieve a circumferential fusion in high-grade spondylolisthesis.

Genetic characterization and molecular epidemiology of foot-and-mouth disease viruses isolated from Afghanistan in 2003-2005.

Foot-and-mouth disease virus (FMDV) isolates collected from various geographic locations in Afghanistan between 2003 and 2005 were genetically characterized, and their phylogeny was reconstructed utilizing nucleotide sequences of the complete VP1 coding region. Three serotypes of FMDV (types A, O, and Asia 1) were identified as causing clinical disease in Afghanistan during this period. Phylogenetic analysis revealed that the type A viruses were most closely related to isolates collected in Iran during 2002-2004. This is the first published report of serotype A in Afghanistan since 1975, therefore indicating the need for inclusion of serotype A in vaccine formulations that will be used to control disease outbreaks in this country. Serotype O virus isolates were closely related to PanAsia strains, including those that originated from Bhutan and Nepal during 2003-2004. The Asia 1 viruses, collected along the northern and eastern borders of Afghanistan, were most closely related to FMDV isolates collected in Pakistan during 2003 and 2004. Data obtained from this study provide valuable information on the FMDV serotypes circulating in Afghanistan and their genetic relationship with strains causing FMD in neighboring countries.

Pandemic strain of foot-and-mouth disease virus serotype O.

A particular genetic lineage of foot-and-mouth disease virus (FMDV) serotype O, which we have named the PanAsia strain, was responsible for an explosive pandemic in Asia and extended to parts of Africa and Europe from 1998 to 2001. In 2000 and 2001, this virus strain caused outbreaks in the Republic of Korea, Japan, Russia, Mongolia, South Africa, the United Kingdom, Republic of Ireland, France, and the Netherlands, countries which last experienced FMD outbreaks decades before (ranging from 1934 for Korea to 1984 for the Netherlands). Although the virus has been controlled in all of these normally FMD-free or sporadically infected countries, it appears to be established throughout much of southern Asia, with geographically separated lineages evolving independently. A pandemic such as this is a rare phenomenon but demonstrates the ability of newly emerging FMDV strains to spread rapidly throughout a wide region and invade countries previously free from the disease.