Nighttime bracing versus observation for early adolescent idiopathic scoliosis.

BACKGROUND: Spinal bracing is widely utilized in patients with moderate severity adolescent idiopathic scoliosis with the goal of preventing curve progression and therefore preventing the need for surgical correction. Bracing is typically initiated in patients with a primary curve angle between 25 and 40 degrees, who are Risser sign 0 to 2 and <1-year postmenarchal. The purpose of this study is to determine whether nighttime bracing using a Charleston bending brace is effective in preventing progression of smaller curves (15 to 25 degrees) in skeletally immature, premenarchal female patients relative to current standard of care (observation for curves <25 degrees). METHODS: Premenarchal, Risser 0 female patients presenting to 2 pediatric orthopaedic specialty practices for evaluation of idiopathic scoliosis with Cobb angle measurements between 15 and 25 degrees were selected. They were randomized by location to receive nighttime bending brace treatment or observation. Patients in the observation group were converted to fulltime TLSO wear if they progressed to >25 degrees primary curve Cobb angle. Curve progression was monitored with minimum 2-year follow-up. RESULTS: Sixteen patients in the observation group and 21 patients in the bracing group completed 2-year follow-up. All patients in the observation group progressed to fulltime bracing threshold. In the nighttime bracing group, 29% of the patients did not progress to 25 degrees primary curve magnitude. Rate of progression to surgical magnitude was similar in the 2 groups. CONCLUSIONS: Risser 0 patients presenting with mild idiopathic scoliosis are at high risk for progression to >25 degrees primary curve magnitude. Treatment with the Charleston nighttime bending brace may reduce progression to full-time bracing threshold. No difference in progression to surgical intervention was shown between nighttime bracing and observation for small curves. LEVEL OF EVIDENCE: Level II--therapeutic study (prospective comparative study).

Primary auditory cortex is necessary for the acquisition and expression of categorical behavior.

The primary auditory cortex (ACtx) is critically involved in the association of sensory information with specific behavioral outcomes. Such sensory-guided behaviors are necessarily brain-wide endeavors, requiring a plethora of distinct brain areas, including those that are involved in aspects of decision making, motor planning, motor initiation, and reward prediction. ACtx comprises a number of distinct excitatory cell-types that allow for the brain-wide propagation of behaviorally-relevant sensory information. Exactly how ACtx involvement changes as a function of learning, as well as the functional role of distinct excitatory cell-types is unclear. Here, we addressed these questions by designing a two-choice auditory task in which water-restricted, head-fixed mice were trained to categorize the temporal rate of a sinusoidal amplitude modulated (sAM) noise burst and used transient cell-type specific optogenetics to probe ACtx necessity across the duration of learning. Our data demonstrate that ACtx is necessary for the ability to categorize the rate of sAM noise, and this necessity grows across learning. ACtx silencing substantially altered the behavioral strategies used to solve the task by introducing a fluctuating choice bias and increasing dependence on prior decisions. Furthermore, ACtx silencing did not impact the animal's motor report, suggesting that ACtx is necessary for the conversion of sensation to action. Targeted inhibition of extratelencephalic projections on just 20% of trials had a minimal effect on task performance, but significantly degraded learning. Taken together, our data suggest that distinct cortical cell-types synergistically control auditory-guided behavior and that extratelencephalic neurons play a critical role in learning and plasticity.

Can we alter the natural history of osteoarthritis after SCFE with early realignment?

In situ fixation has been the gold standard for the treatment of slipped capital femoral epiphysis for some time. This technique has been popular despite obligate residual proximal femoral deformity due to the increased risk for catastrophic avascular necrosis of the femoral head with closed manipulation and historical open reduction techniques. As the body of evidence regarding long-term outcome has grown, it has become evident that early osteoarthritis is common after in situ or conservative treatment because of femoroacetabular impingement of the deformed femoral neck on the acetabular rim. New techniques have been developed that show promise in preventing the early onset of osteoarthritis while minimizing the risk of avascular necrosis with early realignment of the proximal femoral anatomy and elimination of femoroacetabular impingement.

Physeal stapling versus 8-plate hemiepiphysiodesis for guided correction of angular deformity about the knee.

BACKGROUND: Angular deformity in the lower extremities results in cosmetic deformity, gait disturbance, pain, and early joint degeneration. Corrective osteotomy is the gold standard for angular deformity, but is a major surgical intervention with significant incidence of complication. For these reasons, hemiepiphysiodesis is an attractive alternative in the growing child to allow "guided growth" to correct the angular deformity. Physeal stapling has proven success, but hardware prominence or failure has been problematic. Recently, the tension band plate construct ("8-plate") has been promoted for hemiepiphysiodesis, citing ease of surgical technique and more rapid rate of correction. We sought to test the claim that the 8-plate effected a more rapid correction of angular deformity with a lower complication rate. METHODS: Hemiepiphysiodesis for angular deformity in 63 lower extremities from 2000 to 2007 were retrospectively reviewed. Thirty-nine limbs received staple hemiepiphysiodesis and 24 received 8-plate hemiepiphysiodesis. Angular measurements were compared preoperatively, during the first year postoperatively, and at the time of hardware removal or skeletal maturity. Complications requiring additional surgery for the correction of angular deformity were noted in each group. RESULTS: There was no difference between the 2 groups in the rate of correction (approximately 10 degrees/y, P=0.48). Complication rates were similar (12.8% vs. 12.5%, P=1.0). Patients with abnormal physes (eg, Blount disease, skeletal dysplasias) had a higher complication rate (27.8% vs. 6.7% for patients with normal physes, P=0.04) with no difference between the 8-plate and staple groups (P=1.0). The patients in the 8-plate group were significantly younger than those in the staple group (P=0.04). CONCLUSIONS: The 8-plate is as effective as staple hemiepiphysiodesis for guided correction of angular deformity with respect to rate of correction and complications, even in somewhat younger patients. Higher complication rates are observed in patients with pathologic physes.

The effect of kneeling during spine surgery on leg intramuscular pressure.

BACKGROUND: Acute compartment syndrome has been an underreported complication during spine surgery with the patient positioned on the so-called 90/90 kneeling frame (with 90 degrees of both hip and knee flexion), presumably because of elevated intramuscular pressures in the dependent leg compartments. The purpose of the present study was to characterize and quantify certain parameters that affect the risk for acute compartment syndrome experimentally and to make objective comparisons with other spine surgery positions. METHODS: Eight healthy volunteers were positioned in three spine surgery positions: the 90/90 kneeling position, the so-called 45/45 suspended position (with the hips and knees both flexed to 45 degrees with the legs suspended on a sling), and the prone position. Intramuscular pressures were measured in all four left leg compartments with slit catheters. Local blood pressure and applied load beneath the leg were also measured. RESULTS: The 90/90 kneeling position was associated with significantly increased intramuscular pressure in the anterior compartment (30.8 +/- 5.7 mm Hg) in comparison with the prone position (13.5 +/- 1.7 mm Hg) and the 45/45 suspended position (13.8 +/- 1.7 mm Hg). In the 90/90 kneeling position, these values correlated with subject weight (r = 0.72, p = 0.045) and the applied body weight load measured beneath the leg (r = 0.74, p = 0.037). The mean differences between intramuscular pressure and ankle blood pressure were more pronounced as the position of the ankle dropped below the level of the heart in the 45/45 suspended and the 90/90 kneeling positions. CONCLUSIONS: The 90/90 kneeling position results in elevated intramuscular pressure in the anterior compartment of the leg. This elevated pressure correlates also with subject weight. The 90/90 kneeling position may predispose patients to the development of an acute compartment syndrome during prolonged spine surgery, with heavier patients being at increased risk. In certain instances, the surgeon may consider using the 45/45 suspended position to minimize this risk.

Noninvasive measurements of intramuscular pressure using pulsed phase-locked loop ultrasound for detecting compartment syndromes: a preliminary report.

OBJECTIVES: To develop a human model for compartment tamponade and test the efficacy of ultrasonic pulsed phase-locked loop (PPLL) fascial displacement waveform analysis for noninvasive measurement of intramuscular pressure (IMP). DESIGN: Human subject experiment. SETTING: University Level 1 trauma center. PARTICIPANTS: Nine male and 1 female volunteers (age 20 to 59),3 male acute compartment syndrome (ACS) patients (age 31 to 38). INTERVENTION: Thigh tourniquet was inflated in a stepwise fashion from 40 to 100 mm Hg to increase IMP transiently in volunteers. MAIN OUTCOME MEASUREMENTS: Invasive IMP by slit catheter and PPLL fascial displacement waveform in volunteers with model ACS and patients with ACS. RESULTS: In the model compartment tamponade group, thigh cuff occlusion increased IMP in the anterior compartment from a mean of 12.1 mm Hg (SE = 1.5) to a mean of 27.4 mm Hg (SE = 2.4, N = 8, P < 0.0001). By fast Fourier transform, the ratio of the amplitude of the fundamental frequency to the amplitude of the second harmonic frequency of the fascial displacement waveform as measured by PPLL increased from a resting mean of 1.12 (SE = 0.07) to a mean of 1.85 (SE = 0.18) under the same protocol (N = 6, P = 0.001). Combined data with compartment syndrome patients revealed linear correlation between IMP and PPLL with an R value of 0.8887. CONCLUSIONS: Subarterial thigh cuff pressure causes a significant and transient increase in IMP, serving as a model for anterior compartment tamponade. PPLL is able to detect fascial displacement waveforms corresponding to arterial pulsation and furthermore distinguishes between normal and elevated IMP. There is a linear correlation between PPLL measurements and invasive IMP. The PPLL shows potential utility as a device for noninvasive measurement of IMP for detecting compartment syndromes.

Core Decompression with Synthetic Grafting as a Joint Preservation Strategy in Humeral Avascular Necrosis Due to Sickle Cell Anemia: A Case Report.

INTRODUCTION: Avascular necrosis (AVN) of the femoral or humeral heads in patients with sickle cell anemia is a common and painful condition. There is currently no gold standard treatment protocol for this condition. Typically, the pain is managed with narcotics and activity restriction until there has been collapse of the subchondral bone with a degree of arthrosis sufficient to warrant total joint arthroplasty. This method entails prolonged pain for the patient and decreases the ability to function occupationally and recreationally. CASE REPORT: A 51-year-old African-American woman with a history of sickle cell anemia presented for the evaluation of significant bilateral shoulder pain that was confirmed to be AVN via radiographs and magnetic resonance imaging of both her humeral heads without joint collapse. She tried and failed conservative management with physical therapy and optimization of sickle cell treatment with pain medications for years, so she desired surgical management. Arthroscopically assisted core decompression of her humeral heads with synthetic grafting was performed in an attempt at joint preservation. CONCLUSION: This report demonstrates a technique of staged decompression of necrotic bone in the bilateral humeral heads with synthetic bone grafting to determine if this could function as a joint preservation strategy. This procedure was considered successful to alleviate the patients' pain in both of her arms. The application of this procedure is significant because it could be used in various future medical joint preservation cases for a wide range of patients.

Actomyosin purse strings: renewable resources that make morphogenesis robust and resilient.

Dorsal closure in Drosophila is a model system for cell sheet morphogenesis and wound healing. During closure two sheets of lateral epidermis move dorsally to close over the amnioserosa and form a continuous epidermis. Forces from the amnioserosa and actomyosin-rich, supracellular purse strings at the leading edges of these lateral epidermal sheets drive closure. Purse strings generate the largest force for closure and occur during development and wound healing throughout phylogeny. We use laser microsurgery to remove some or all of the purse strings from developing embryos. Free edges produced by surgery undergo characteristic responses as follows. Intact cells in the free edges, which previously had no purse string, recoil away from the incision and rapidly assemble new, secondary purse strings. Next, recoil slows, then pauses at a turning point. Following a brief delay, closure resumes and is powered to completion by the secondary purse strings. We confirm that the assembly of the secondary purse strings requires RhoA. We show that alpha-actinin alternates with nonmuscle myosin II along purse strings and requires nonmuscle myosin II for its localization. Together our data demonstrate that purse strings are renewable resources that contribute to the robust and resilient nature of closure.