Maximal Force Generated by Magnetically Controlled Growing Rods Decreases With Rod Lengthening.

OBJECTIVES: To evaluate the maximal force generated by magnetically controlled growing rods (MCGRs) at three different lengthened positions. SUMMARY OF BACKGROUND DATA: The introduction of MCGRs has been met with great enthusiasm by surgeons managing early-onset scoliosis. These devices offer the potential to decrease the cost and morbidity associated with repeated surgeries, compared to traditional growing rods. One potential negative consequences of growing rod treatments is the law of diminishing returns, where the spine length gained decrease with each subsequent lengthening. The cause of this phenomenon is unknown and probably multifactorial, yet it may be affected by the strength of the lengthening mechanism in the MCGRs. METHODS: Twelve MCGRs (90-mm actuator length) were obtained and tested to evaluate the maximal force generated at different lengths. The maximal lengthening force measured in pounds-of-force generated by each rod was recorded at expansion lengths of 0, 25, and 40 mm. Longitudinal analysis was performed using mixed effects linear regression to account for repeated measures and variability between individual implants. RESULTS: At 0 mm of actuator lengthening, the mean maximum force was 46.8 lb (standard deviation [SD] 2.06, range 43-50). At 25 mm of expansion, the mean maximum force was 44.9 lb (SD 2.48, range 39.4-49.5). At 40 mm of lengthening, the mean maximum force was 43.2 lb (SD 5.56, range 27.3-49.1). In the mixed effects linear model, there was a statistically significant decrease in the maximal force generated with progressive MCGR lengthening, at an average decrease of 0.089 lb of force (95% CI, 0.030-0.148; p = .003) per millimeter of lengthening. CONCLUSION: There is a small but statistically significant decrease in the maximal force generated by MCGR as the rods are lengthened. The decrease in force generated may result in diminished spine length gained with each subsequent MCGR lengthening. LEVEL OF EVIDENCE: Level IV.

Indirect costs associated with surgery for low back pain-a secondary analysis of clinical trial data.

This study examines the indirect costs associated with surgery for axial low back pain using data obtained from a prospective multicenter clinical trial that compared Charité artificial disc replacement with anterior lumbar interbody fusion using iliac crest bone graft. While 75% of study subjects reported full- or part-time employment prior to surgery, this percentage dropped to 45% at 6 weeks postoperatively. Return to preoperative employment levels occurred at approximately 6 months postoperatively. Two years after surgery, employment levels were 16% higher than preoperative levels. Lost productivity related to absenteeism resulted in lost wages averaging $2884 per patient during the first postoperative year. Although short-term indirect costs of surgery are substantial from a societal perspective, the higher employment rate at 2 years suggests a long-term economic benefit. The findings demonstrate the significant, though not surprising, impact of spinal disability on productivity, and the importance of including measurement of lost productivity and return to work in the economic evaluation of related interventions.

A history of bracing for idiopathic scoliosis in North America.

The care of the patient with scoliosis has a history extending back over two millennia with cast and brace treatment being a relatively recent endeavor, the modern era comprising just over half a century. Much of the previous literature provides a modest overview with emphasis on the history of the operative management. To better understand the current concepts of brace treatment of scoliosis, an appreciation of the history of bracing would be helpful. As such, we review the history of the treatment of scoliosis with an emphasis on modern brace treatment, primarily from a North American perspective. Our review utilizes consideration of historical texts as well as current treatises on the history of scoliosis and includes discussion of brace development with their proponents' rationale for why they work along with an appraisal of their clinical outcomes. We provide an overview of the current standards of care and the braces typically employed toward that standard including: the Milwaukee brace, the Wilmington brace, the Boston brace, the Charleston brace, the Providence brace and the SpineCor brace. Finally, we discuss future trends including improvements in methods of determining the critical period of peak growth velocity in children with scoliosis, the exciting promise of gene markers for progressive scoliosis and "internal bracing" options.

Early outcomes of soft tissue sarcomas presenting with metastases and treated with chemotherapy.

OBJECTIVES: The purpose of this study is to describe outcomes for patients with metastatic soft tissue sarcoma treated with chemotherapy. METHODS: We retrospectively reviewed the records of 383 soft tissue sarcoma patients treated at our institution from 1997 to 2006. Thirty-five patients met the inclusion criteria-metastatic disease on presentation; primary tumor outside the abdomen; treatment with chemotherapy; and minimum follow-up of 3 months. Treatments were individualized and determined by a multidisciplinary oncology team. Patient survival was calculated from the diagnostic biopsy to the date of death or last follow-up using the Kaplan-Meier method. RESULTS: Mean age was 47 years (range 17-74 years). Most common tumors involved were MFH and leiomyosarcoma. Sixteen of 35 (46%) patients had died at last follow-up. Mean patient survival was 24 months (range 4-102). The 2-year and 5-year survival rates were 64% and 24%, respectively. Twenty-nine patients (83%) presented with pulmonary metastasis, 6 with bone metastases (17%), 4 with regional node metastases (11%), and 4 with soft tissue metastases (11%). Survival was the same for those with pulmonary and only extrapulmonary metastases. The 10 patients with complete resection or complete chemotherapy response of all detectable lesions had longer mean survival (34 months) than the 25 patients who had partial/no resection or response (20 months) (P = 0.02). CONCLUSIONS: Soft tissue sarcoma patients presenting with metastatic disease have a low survival rate, but complete eradication of tumor correlated with longer survival. Longer-term studies especially those tracking the outcome of complete responders and those completely resected will help determine the efficacy of chemotherapy.

Chronic spinal cord injury in the pediatric population: does magnetic resonance imaging correlate with the International Standards for Neurological Classification of Spinal Cord Injury examination?

STUDY DESIGN: Prognostic, retrospective case series. OBJECTIVE.: This study is part of a larger investigation to develop and validate a standardized and reliable method to evaluate and classify the neurologic consequence of spinal cord injury (SCI) in children. Such an instrument may also find use in the evaluation of patients with concomitant brain injury and/or cognitive impairment. We examined the relationship between the International Standards for Neurologic Classification of Spinal Cord Injury (ISCSCI) examination and magnetic resonance imaging (MRI) findings in a pediatric SCI population. SUMMARY OF BACKGROUND DATA: Recently, the reliability of the ISCSCI in young children with SCI who are unable to cognitively engage in the examination has been called into question. This has important implications as appropriate classification of these patients is necessary for prognostication, follow-up care, and appropriate placement into clinical trials. METHODS: Our longitudinal pediatric SCI database was reviewed for children with chronic SCI (>6 months), ISCSCI examinations performed by experienced testers, and adequate MRIs of the spine. ISCSCI results were correlated with MRI findings. Twenty-six subjects were identified. RESULTS: Overall, good to excellent relationships between ISCSCI neurologic level (NL) and MRI level of injury were found [Kendall tau correlation coefficient 0.90 (P < 0.001)]. The ISCSCI NL was on an average, two-thirds of a vertebral level cephalad to the center of the lesion on MRI. One child with MRI evidence of cord disruption tested incomplete at ISCSCI examination. CONCLUSION: The ISCSCI examination was found to have good to excellent relationships with MRI level in children with chronic SCI. Our results suggest MRI may be a useful adjunct for the determination of NL in children unable to participate with the examination. Our results also suggest caution in using the ISCSCI for the determination of completeness in young children. Further research into new methods (e.g., diffusion tensor imaging) to determine completeness of injury is warranted.

Fractures of the distal humeral metaphyseal-diaphyseal junction in children.

BACKGROUND: To our knowledge, there is no report in the English-language literature of metaphyseal-diaphyseal junction fractures of the distal humerus in children. The purpose of this study was to review our experience with this uncommon fracture. METHODS: Between 1998 and 2004, 422 displaced supracondylar humerus fractures underwent operative reduction and fixation at our institution. A retrospective review of medical records and radiographs revealed that 14 (3.3%) of these fractures occurred at the metaphyseal-diaphyseal junction just proximal to the olecranon fossa. In 8 patients, the fracture line was oblique (group A), and in 6 patients, the fracture line was transverse (group B). RESULTS: Average age at the time of fracture was 4.9 years (range, 1.5-10 years). All patients were treated by closed reduction and Kirschner wire fixation and had at least 1-year follow-up. In group A, operative time for reduction and fixation was significantly increased in comparison to the 408 remaining supracondylar humerus fractures. However, the clinical course in group A was uncomplicated, and no loss of fixation at follow-up was noted. The operative time in group B was even longer. These fractures were more problematic as loss of fixation occurred in 5 of the 6 patients, 4 occurring in the sagittal plane. In addition, multiple complications arose in group B including reoperation, cubitus varus, pin migration, and prolonged loss of motion. CONCLUSION: Metaphyseal-diaphyseal junction fractures of the distal humerus in children are rare but can be problematic. The transverse fracture pattern requires additional attention in the operating room with optimal pin fixation. Close postoperative follow-up is necessary. The oblique fracture pattern, while requiring increased time in the operating room for reduction and fixation, is typically stable with the usual fixation used for supracondylar humerus fractures. In summary, metaphyseal-diaphyseal junction fractures of the distal humerus are uncommon elbow fractures in children that should be differentiated from the more common supracondylar humerus fracture for optimal outcomes. LEVEL OF EVIDENCE: Therapeutic level 4 (case series).

Case report: cefazolin-induced hemolytic anemia.

Antibiotic-induced hemolytic anemia is a rare complication. Prophylactic cephalosporins are widely used in patients having orthopaedic procedures. When there is a precipitous drop in hemoglobin levels, it is important for the clinician to consider the possibility of drug-induced anemia when other causes of blood loss have been excluded. We present a patient with no prior drug allergies who had antibiotic-induced hemolytic anemia develop after total knee arthroplasty.