Differential growth and development of the upper and lower human thorax

The difficulties in quantifying the 3D form and spatial relationships of the skeletal components of the ribcage present a barrier to studies of the growth of the thoracic skeleton. Thus, most studies to date have relied on traditional measurements such as distances and indices from single or few ribs. It is currently known that adult-like thoracic shape is achieved early, by the end of the second postnatal year, with the circular cross-section of the newborn thorax transforming into the ovoid shape of adults; and that the ribs become inclined such that their anterior borders come to lie inferior to their posterior. Here we present a study that revisits growth changes using geometric morphometrics applied to extensive landmark data taken from the ribcage. We digitized 402 (semi) landmarks on 3D reconstructions to assess growth changes in 27 computed tomography-scanned modern humans representing newborns to adults of both sexes. Our analyses show a curved ontogenetic trajectory, resulting from different ontogenetic growth allometries of upper and lower thoracic units. Adult thoracic morphology is achieved later than predicted, by diverse modifications in different anatomical regions during different ontogenetic stages. Besides a marked increase in antero-posterior dimensions, there is an increase in medio-lateral dimensions of the upper thorax, relative to the lower thorax. This transforms the pyramidal infant thorax into the barrel-shaped one of adults. Rib descent is produced by complex changes in 3D curvature. Developmental differences between upper and lower thoracic regions relate to differential timings and rates of maturation of the respiratory and digestive systems, the spine and the locomotor system. Our findings are relevant to understanding how changes in the relative rates of growth of these systems and structures impacted on the development and evolution of modern human body shape.

Spinal deformities among pupils - A growing issue

This paper presents data obtained by somatic examination of pupils in the 1st, 5th and 8th grade of elementary school in the area of the Town of Split in the period of three school years. There was a corresponding increase in bad posture, over the school years observed, with an increase in kyphosis among pupils of both genders, The occurrence of kyphosis among boys ranged from 0.49% in the first grade, 0.88% in the fifth grade, to 2.11% in the eighth grade. The frequency of kyphosis was at first somewhat lower in girls; however, it significantly increased later, exceeding the frequency among male students. Thus, kyphosis in girls ranged from 0.42% in the first grade, 0.88% in the fifth grade, and even up to 4.60% in the eighth grade of elementary school. Therefore, the ratio of 14-year old girls to boys with kyphosis was 2.2:1. The frequency of scoliosis among boys ranged from 0.55% in the first grade, 2.13% in the fifth grade, and up to 3.01% in the eighth grade. Throughout the whole period, the frequency of this deformity was higher in girls than boys. Thus, scoliosis in female students ranged from 0.89% in the first grade, 3.23% in the fifth grade, and even up to 5.70% in the eighth grade. It is obvious that scoliosis as a deformity affects girls significantly more often than boys during the entire period of elementary school, and the ratio at the age of 14 is 1.8:1.

Marginal increment analysis: a new statistical approach of testing for temporal periodicity in fish age verification

This paper proposes a new and flexible statistical method for marginal increment analysis that directly accounts for periodicity in circular data using a circular-linear regression model with random effects. The method is applied to vertebral marginal increment data for Alaska skate Bathyraja parmifera. The best fit model selected using the AIC indicates that growth bands are formed annually. Simulation, where the underlying characteristics of the data are known, shows that the method performs satisfactorily when uncertainty is not extremely high.

Comparative study of longevity, growth, and biomarkers of metal detoxication and oxidative stress between normal and deformed Aphanius fasciatus (Pisces, Cyprinodontidae)

This study compared fish longevity, growth, and oxidative stress between normal and deformed Aphanius fasciatus collected from the Gulf of Gabes. For this purpose, fish were collected from control (S1) and polluted (S2) sites in Tunisian coast and percentages of spinal deformities were determined. Oxidative stress biomarkers were also compared between normal and deformed fish, including levels of protein sulfhydryl (SH), malondialdehyde (MDA), and metallothioneins (MT), as well as activities of superoxide dismutase (SOD) and alkaline phosphatase (AP). Levels of heavy metals (Cd, Cu, and Zn) and polycyclic aromatic hydrocarbons (PAH) were also measured. Data showed that the highest occurrence of deformities was observed in younger fish and decreased significantly thereafter with age. Chemical analysis demonstrated high levels of heavy metals and PAH at polluted sites compared to a reference location. In deformed fish, a growth perturbation marked by a decrease of growth rate and condition index (CI), a high accumulation of Cd was noted. In addition, oxidative stress marked by changes in the studied biomarkers was observed. Taken together, oxidative stress, diminished longevity, and a disturbance of growth may be considered to be responsible factors contributing to spinal deformities.

Developmental structure of the vertebral column, fins, scutes and scales in bester sturgeon, a hybrid of beluga Huso huso and sterlet Acipenser ruthenus

In the larval bester, a hybrid sturgeon of beluga Huso huso and sterlet Acipenser ruthenus, development of cartilage around the notochord began 7 days post hatch (dph) (14.0 mm, total length, L(T)). The vertebral cartilage develops in the following sequence: basidorsals and basiventrals, neural canals, neural spines and ribs. The development of ribs remained incomplete in the largest specimen (181 dph, 179 mm L(T) ) that was examined. Endoskeletal development of the fins began 4 dph for the dorsal and anal fins, 6 dph for the pectoral fin and 10 dph for the caudal and pelvic fins. Complete elements of all fins were observed by 91 dph and complete ossification of fin rays was observed by 122 dph in the double-stained specimens. Observation of the histological sections, however, suggested that ossification occurred soon after the formation of the organic matrix in the fin rays. Dorsal scutes were first visible by 25 dph, followed by the lateral and ventral scutes, which were visible by 37 and 44 dph, respectively. The number of scutes was fixed at 44, 59 and 91 dph and ossification was complete by 59 (dorsal) and 91 dph (lateral and ventral scutes) in the double-stained specimens. Ossification occurred soon after the formation of the scute organic matrix in the histological sections. Four types of scales were observed in the H. huso×A. ruthenus hybrid. Median predorsal, preanal and small scales on the anterior section of the head were visible by 59 dph. Scales on the caudal fin were visible by 91 dph and a variable assemblage of scales anterior to the anal fin was visible by 122 dph. Both the scutes and scales developed in a process that is similar to that of intramembranous ossification.

Age and growth of endangered smalltooth sawfish (Pristis pectinata) verified with LA-ICP-MS analysis of vertebrae

Endangered smalltooth sawfish (Pristis pectinata) were opportunistically sampled in south Florida and aged by counting opaque bands in sectioned vertebrae (n = 15). Small sample size precluded traditional age verification, but fish collected in spring and summer had translucent vertebrae margins, while fish collected in winter had opaque margins. Trends in Sr:Ca measured across vertebrae with laser ablation-inductively coupled plasma-mass spectrometry corresponded well to annual salinity trends observed in sawfish estuarine nursery habitats in south Florida, thus serve as a chemical marker verifying annual formation of opaque bands. Based on that finding and assumptions about mean birth date and timing of opaque band formation, estimated age ranged from 0.4 y for a 0.60 m total length (TL) male to 14.0 y for a 4.35 m TL female. Von Bertalanffy growth parameters computed from size at age data were 4.48 m for L_∞, 0.219 y⁻¹for k, and −0.81 y for t₀. Results of this study have important implications for sawfish conservation as well as for inferring habitat residency of euryhaline elasmobranchs via chemical analysis of vertebrae.

Genetic deletion of NR3A accelerates glutamatergic synapse maturation

Glutamatergic synapse maturation is critically dependent upon activation of NMDA-type glutamate receptors (NMDARs); however, the contributions of NR3A subunit-containing NMDARs to this process have only begun to be considered. Here we characterized the expression of NR3A in the developing mouse forebrain and examined the consequences of NR3A deletion on excitatory synapse maturation. We found that NR3A is expressed in many subcellular compartments, and during early development, NR3A subunits are particularly concentrated in the postsynaptic density (PSD). NR3A levels dramatically decline with age and are no longer enriched at PSDs in juveniles and adults. Genetic deletion of NR3A accelerates glutamatergic synaptic transmission, as measured by AMPAR-mediated postsynaptic currents recorded in hippocampal CA1. Consistent with the functional observations, we observed that the deletion of NR3A accelerated the expression of the glutamate receptor subunits NR1, NR2A, and GluR1 in the PSD in postnatal day (P) 8 mice. These data support the idea that glutamate receptors concentrate at synapses earlier in NR3A-knockout (NR3A-KO) mice. The precocious maturation of both AMPAR function and glutamate receptor expression are transient in NR3A-KO mice, as AMPAR currents and glutamate receptor protein levels are similar in NR3A-KO and wildtype mice by P16, an age when endogenous NR3A levels are normally declining. Taken together, our data support a model whereby NR3A negatively regulates the developmental stabilization of glutamate receptors involved in excitatory neurotransmission, synaptogenesis, and spine growth.

Beef carcasses with larger eye muscle areas, lower ossification scores and improved nutrition have a lower incidence of dark cutting

This study evaluated the effect of eye muscle area (EMA), ossification, carcass weight, marbling and rib fat depth on the incidence of dark cutting (pH(u)>5.7) using routinely collected Meat Standards Australia (MSA) data. Data was obtained from 204,072 carcasses at a Western Australian processor between 2002 and 2008. Binomial data of pH(u) compliance was analysed using a logit model in a Bayesian framework. Increasing eye muscle area from 40 to 80 cm², increased pH(u) compliance by around 14% (P<0.001) in carcasses less than 350 kg. As carcass weight increased from 150 kg to 220 kg, compliance increased by 13% (P<0.001) and younger cattle with lower ossification were also 7% more compliant (P<0.001). As rib fat depth increased from 0 to 20mm, pH(u) compliance increased by around 10% (P<0.001) yet marbling had no effect on dark cutting. Increasing musculature and growth combined with good nutrition will minimise dark cutting beef in Australia.

Reassessment of spiny dogfish Squalus acanthias age and growth using vertebrae and dorsal-fin spines

Male and female spiny dogfish Squalus acanthias were collected in the western North Atlantic Ocean in the Gulf of Maine between July 2006 and June 2009. Squalus acanthias ranged from 25 to 102 cm stretch total length and were caught during all months of the year except January. Age estimates derived from banding patterns visible in both the vertebrae and second dorsal-fin spines were compared. Vertebral growth increments were visualized using a modified histological staining technique, which was verified as appropriate for obtaining age estimates. Marginal increment analysis of vertebrae verified the increment periodicity, suggesting annual band deposition. Based on increased precision and accuracy of age estimates, as well as more biologically realistic parameters generated in growth models, the current study found that vertebrae provided a more reliable and accurate means of estimating age in S. acanthias than the second dorsal-fin spine. Age estimates obtained from vertebrae ranged from <1 year-old to 17 years for male and 24 years for female S. acanthias. The two-parameter von Bertalanffy growth model fit to vertebrae-derived age estimates produced parameters of L∞ = 94·23 cm and k = 0·11 for males and L∞ = 100·76 cm and k = 0·12 for females. While these growth parameters differed from those previously reported for S. acanthias in the western North Atlantic Ocean, the causes of such differences were beyond the scope of the current study and remain to be determined.

The in-vivo effect of torque on growth in caudal vertebrae

Numerous studies involving axial distraction and compression of the spine indicate that longitudinal loading affects the vertebral growth plate as well as modulation of spinal growth. Furthermore, asymmetric loading is involved in curve progression as a result of vertebral bone changes and disc wedging. As with longitudinal loading, direct or indirect application of torque to the growth plate may have an influence as well. A study was undertaken to develop a fixture that may be applied in-vivo to generate controlled torsional loads and to examine the effect of such torsional loads on the growth plate in caudal vertebrae. It is shown that application of torque leads to curvature in the morphology of the growth plate, a reduced width (medial to lateral distance of the growth plate) and remarkably increased thickness (height of 3 physeal zones in the growth plate) and dramatically widened disc space.

The growing spine: how spinal deformities influence normal spine and thoracic cage growth

PURPOSE

This article aims to provide an overview of how spinal deformities can alter normal spine and thoracic cage growth.

METHODS

Some of the data presented in this article are gathered from studies performed in 1980 and 1990, and their applicability to populations of different ethnicity, geography or developmental stage has not yet been elucidated. In the present article, older concepts have been integrated with newer scientific data available to give the reader the basis for a better understanding of both normal and abnormal spine and thoracic cage growth.

RESULTS

A thorough analysis of different parameters, such as weight, standing and sitting height, body mass index, thoracic perimeter, arm span, T1-S1 spinal segment length, and respiratory function, help the surgeon to choose the best treatment modality. Respiratory problems can develop after a precocious vertebral arthrodesis or as a consequence of pre-existing severe vertebral deformities and can vary in patterns and timing, according to the existing degree of deformity. The varying extent of an experimental arthrodesis also affects differently both growth and thoracopulmonary function.

CONCLUSIONS

Growth is a succession of acceleration and deceleration phases and a perfect knowledge of normal growth parameters is mandatory to understand the pathologic modifications induced on a growing spine by an early onset spinal deformity. The challenges associated with the growing spine for the surgeon include preservation of the thoracic spine, thoracic cage, and lung growth without reducing spinal motion.

Clinical and radiological outcome of the growing rod technique in the management of scoliosis in young children

OBJECTIVE

The aim of this study was to investigate the effects of growing rod treatment on the clinical and radiographic outcome and respiratory function of young children with scoliosis.

METHODS

Data from 25 patients (24 females, 1 male) who underwent surgical treatment with growing rods for scoliosis between 1997 and 2007 were evaluated retrospectively. Dual growing rods were used in 16 patients and single growing rods in 9. Patients' average age was 7.38 ± 3.8 years at the initial surgery. Cobb angle, T1-S1 length, and instrumentation length were measured radiographically. Respiratory functions were evaluated at the final follow-up.

RESULTS

Patients received an average of 4.2 lengthening treatments over an average period of 44.9 months. Cobb angles improved from 56.7° to 25.1° after final fusion. T1-S1 length increased from 27.2 ± 3.4 to 34.9 ± 3.6 cm after the initial surgery and 38.6 ± 3.7 cm post final fusion. Average growth was 1 ± 0.4 cm per year. Mean values of respiratory parameters at the last follow-up were FVC: 83.5 ± 3.5, FEV: 84.8 ± 5.3, and FVC/FEV1: 1 ± 0.046. Twelve patients experienced complications, of which eight were instrument-related and four medical.

CONCLUSION

The growing rod technique is effective in the treatment of spinal deformity in young scoliosis patients and appropriate for improving both spinal column height and pulmonary function.

The value of different Risser grading systems in determining growth maturity of girls with adolescent idiopathic scoliosis

A grading system for ossification of the iliac apophysis (Risser sign) was developed for skeletal maturity assessment in the United States (US) then adopted with modifications in France (Fr) and other countries. Despite the same name, these systems have important differences. With the aim to analyzing the difference between US and Fr Risser grading systems in determining the growth maturity of girls with adolescent idiopathic scoliosis (AIS), Fifty-three AIS girls undergoing posterior spinal correction with autogenous bone graft were recruited. The Risser grades were recorded for the non-dominant side iliac crest apophysis according to the US and Fr grading systems. Growth activity was determined by standard histologic grades (HGs) on iliac crest cartilage. As a result, Kappa statistics showed poor agreement between two grading systems. The US system showed higher correlation with HGs compared to Fr system by Spearman correlation analysis. It was also found that growth cessation could be determined by Risser grade 5 of US system or Risser grade 4 of Fr system. Furthermore, by employing Receiver Operating Characteristic (ROC) curve analysis, it was found that the Risser grade 4-5 of US system with two years after menarche could be used in determining growth cessation with the highest sensitivity, specificity and accuracy. Hence it was concluded that the US Risser grading system was better in determining maturity of girls with AIS than Fr Risser grading system. By combining years since menarche, the accuracy of Risser grades in determining growth cessation could be enhanced, and the time of weaning from a brace could be advanced.

Abnormal anthropometric measurements and growth pattern in male adolescent idiopathic scoliosis

PURPOSE

The progression of adolescent idiopathic scoliosis is closely correlated with longitudinal growth during puberty. A decreased incidence of curve progression has been found in male patients with adolescent idiopathic scoliosis compared with female patients with the condition. This finding implies that there might be a sexual dimorphism in the pubertal growth patterns of adolescent idiopathic scoliosis patients. Abnormal pubertal growth in female adolescent idiopathic scoliosis patients has been well characterized; however, the pubertal growth patterns of male adolescent idiopathic scoliosis patients have not been reported. We conducted a cross-sectional study of anthropometric measurements to compare the growth patterns of male patients with adolescent idiopathic scoliosis with those of healthy boys during puberty and explore the difference in the pubertal growth patterns of female and male patients with adolescent idiopathic scoliosis.

METHODS

A total of 688 subjects were involved in the study, including 332 male adolescent idiopathic scoliosis patients and 356 age-matched healthy boys. The subjects were categorized according to their chronological ages. Their body weights, heights and arm spans were obtained using standard methods; the corrected body heights of the adolescent idiopathic scoliosis boys were determined using Bjour's equation. The inter-group differences in the anthropometric parameters were analyzed. Multivariate regression analysis was carried out in the adolescent idiopathic scoliosis patients to identify the anthropometric parameters that influence curve severity.

RESULTS

The corrected standing heights and arm spans of male adolescent idiopathic scoliosis patients were similar to those of the matched controls during puberty. However, the body weights of the adolescent idiopathic scoliosis patients who were more than 14 years old were significantly less than those of the control group. The body mass index of the adolescent idiopathic scoliosis patients between the ages of 15 and 17 were also significantly less than those of the control subjects. Moreover, a significantly higher incidence of underweight was found in adolescent idiopathic scoliosis patients (8.6%) than in the controls (3.4%). Upon multivariate regression analysis, body weight and chronological age were identified as independent predictors of curve magnitude in male adolescent idiopathic scoliosis patients. The male adolescent idiopathic scoliosis patients with variable curve patterns exhibited no significant differences in their anthropometric parameters.

CONCLUSIONS

The results showed abnormal pubertal growth in the male adolescent idiopathic scoliosis patients compared with their age- and gender-matched normal controls. Despite similar longitudinal growth, the male patients with adolescent idiopathic scoliosis exhibited significantly lower body weights and a higher incidence of underweight during the later stage of puberty compared with their normal controls. These abnormalities in the pubertal growth of male patients were different from those observed in female patients with adolescent idiopathic scoliosis. Body weight could be an important parameter for further longitudinal studies on the prognostication of curve progression in adolescent idiopathic scoliosis.

Gender- and region-specific variations of estrogen receptor α and β expression in the growth plate of spine and limb during development and adulthood

Although estrogen action is indispensable for normal bone growth in both genders, the roles of estrogen receptors (ERs) in mediating bone growth are not fully understood. The effects of ER inactivation on bone growth are sex and age dependent, and may differ between the axial and appendicular regions. In this study, the spatial and temporal expression of ERα and β in the tibial and spinal growth plates of the female and male rats during postnatal development was examined to explore the possible mechanisms. The level of mRNA was examined and compared with quantitative real-time PCR. The spatial location was determined by immunohistochemical analysis. The 1-, 4-, 7-, 12- and 16-week age stages correspond to early life, puberty and early adulthood after puberty, respectively. Gender- and region-specific differences in ERα and β expression were shown in the growth plates. Mainly nuclear staining of ERα and β immunoreactivity was demonstrated in the spinal and tibial growth plate chondrocytes for both genders. Moreover, our study indicated significant effect of gender on temporal ERα and β expression and of region on temporal ERα/ERβ expression ratio. However, spatial differences of region-related ERα and β expression were not observed. Gender-related spatial changes were detected only at 16 weeks of both spine and limb growth plates. ERα and β immunoreactivity was detected in the resting, proliferative and prehypertrophic chondrocytes in the early life stage and during puberty. After puberty, ERα expression was mainly located in the late proliferative and hypertrophic chondrocytes in female, whereas the expression still extended from the resting to hypertrophic chondrocytes in males. Gender- and region-specific expression patterns of ERα and β gene might be one possible reason for differences in sex- and region-related body growth phenotypes. Gender, age and region differences should be taken into consideration when the roles of ERs in the growth plate are investigated.

Heated indoor swimming pools, infants, and the pathogenesis of adolescent idiopathic scoliosis: a neurogenic hypothesis

BACKGROUND

In a case-control study a statistically significant association was recorded between the introduction of infants to heated indoor swimming pools and the development of adolescent idiopathic scoliosis (AIS). In this paper, a neurogenic hypothesis is formulated to explain how toxins produced by chlorine in such pools may act deleteriously on the infant's immature central nervous system, comprising brain and spinal cord, to produce the deformity of AIS.

PRESENTATION OF THE HYPOTHESIS

Through vulnerability of the developing central nervous system to circulating toxins, and because of delayed epigenetic effects, the trunk deformity of AIS does not become evident until adolescence. In mature healthy swimmers using such pools, the circulating neurotoxins detected are chloroform, bromodichloromethane, dibromochloromethane, and bromoform. Cyanogen chloride and dichloroacetonitrile have also been detected.

TESTING THE HYPOTHESIS

In infants, the putative portals of entry to the blood could be dermal, oral, or respiratory; and entry of such circulating small molecules to the brain are via the blood-brain barrier, blood-cerebrospinal fluid barrier, and circumventricular organs. Barrier mechanisms of the developing brain differ from those of adult brain and have been linked to brain development. During the first 6 months of life cerebrospinal fluid contains higher concentrations of specific proteins relative to plasma, attributed to mechanisms continued from fetal brain development rather than immaturity.

IMPLICATIONS OF THE HYPOTHESIS

The hypothesis can be tested. If confirmed, there is potential to prevent some children from developing AIS.

Asynchronous neuro-osseous growth in adolescent idiopathic scoliosis--MRI-based research

Adolescent idiopathic scoliosis (AIS) is a common worldwide problem and has been treated for many decades; however, there still remain uncertain areas about this disorder. Its involvement and impact on different parts of the human body remain underestimated due to lack of technology in imaging for objective assessment in the past. The advances in imaging technique and image analysis technology have provided a novel approach for the understanding of the phenotypic presentation of neuro-osseous changes in AIS patients as compared with normal controls. This review is the summary of morphological assessment of the skeletal and nervous systems in girls with AIS based on MRI. Girls with AIS are found to have morphological differences in multiple areas including the vertebral column, spinal cord, skull and brain when compared with age- and sex-matched normal controls. Taken together, the abnormalities in the skeletal system and nervous system of AIS are likely to be inter-related and reflect a systemic process of asynchronous neuro-osseous growth. The current knowledge about the anatomical changes in AIS has important implications with respect to the understanding of fundamental pathomechanical processes involved in the evolution of the scoliotic deformity.

Simulated evolution of the vertebral body based on basic multicellular unit activities

A numerical model based on the theory of bone remodeling is proposed to predict the evolution of trabecular bone architecture within the vertebral body and to investigate the process of degeneration in vertebral bone. In this study, particular attention is paid on the description of microstructure changes during the aging process. To take into account the effect of basic multicellular units (BMUs), a set of computational algorithms has been developed. It is assumed that BMU activation probability depends on the state of damaged bone tissue (damage accumulation, ω), which is evaluated according to previous research concerning bone fatigue damage. Combining these algorithms with the finite-element method (FEM), the microstructure of vertebral bone has been predicted for up to 8 simulated years. Moreover, biomechanical material properties have been monitored to investigate the changes of vertebral bone with age. This study shows that the simulation based on BMU activities has the potential to define and predict the morphological evolution of the vertebral body. It can be concluded that the novel algorithms incorporating the coupled effects of both adaptive remodeling and microdamage remodeling could be utilized to gain greater insight into the mechanism of bone loss in the elderly population.

Can VEPTR(®) control progression of early-onset kyphoscoliosis? A cohort study of VEPTR(®) patients with severe kyphoscoliosis

BACKGROUND

Kyphoscoliosis is considered a relative contraindication to treatment with the Vertical Expandable Prosthetic Titanium Rib (VEPTR(®); Synthes Inc, Paoli, PA). Nevertheless, patients do present with early-onset kyphoscoliosis and thoracic insufficiency syndrome, and no suitable alternative treatments are currently available. However, it is unclear whether VEPTR(®) is reasonable for treating patients with kyphoscoliosis.

QUESTIONS/PURPOSES

We determined whether VEPTR(®) controls progression in patients with kyphoscoliosis and, if so, what methods might be used to improve control of deformity progression in these patients.

PATIENTS AND METHODS

We retrospectively reviewed 14 patients who had VEPTR(®) treatment of early-onset kyphoscoliosis. Degrees of kyphosis and scoliosis before, during, and after treatment were measured, and levels of instrumentation, thoracic dimensions, and complications were recorded. Minimum followup was 1.7 years (average, 5.8 years; range, 1.7-12.8 years).

RESULTS

While scoliosis was stabilized, kyphosis increased a mean of 22° at last followup. Supple kyphosis became rigid during treatment. Proximal cradle cutout was a recurring problem. Distal anchors placed too proximally had inadequate lever arms to control kyphosis.

CONCLUSIONS

Progression of kyphosis can be minimized during VEPTR(®) treatment by early extension of the construct to the second ribs bilaterally, distal extension of hybrid constructs to the pelvis, use of bilateral hybrid VEPTR(®) implants, and use of redesigned VEPTR(®) constructs that enhance fixation at the upper end. While our early results suggest these devices control progression of kyphosis, longer followup with more patients will be required to confirm the concept in these patients.

Surgical technique: modern Luqué trolley, a self-growing rod technique

BACKGROUND

The challenge when managing early-onset scoliosis (EOS) is to prevent curve progression while maintaining spinal growth. Current surgical treatments (growing rods, VEPTR) require repetitive interventions to lengthen the implants.

QUESTIONS/PURPOSES

We asked whether a modern Luqué trolley construct could achieve and maintain scoliosis correction in EOS during spinal growth without the need for repetitive surgeries, thus decreasing the morbidity of the surgical treatment.

METHODS

We retrospectively reviewed five patients who underwent a modern Luqué trolley construct between 2003 and 2008. This construct consists of inserting apical gliding spinal anchors using muscle-sparing techniques to the proximal and distal fixed anchors found in the dual growing rod construct. We documented age at surgery, correction and maintenance of deformity, spinal growth, number of procedures, and complications.

RESULTS

The primary curve was corrected from 60° to 21° and was maintained at 21° at a minimum followup of 2 years (mean, 4 years; range, 2-5.5 years). An average of 10 vertebrae was spanned allowing the spine to grow a mean of 3 cm over 4 years, representing a mean of 77% of the expected growth. Two of the five cases outgrew the construct requiring lengthening of rods. One patient had gradual recurrence of deformity without substantial axial growth that required revision surgery after 4 years.

CONCLUSION

Modifications of the Luqué trolley may be useful for managing EOS without the morbidity of repetitive surgery. However, questions such as the effect of wear debris and the risk of spontaneous fusions still remain.

VEPTR™ growing rods for early-onset neuromuscular scoliosis: feasible and effective

BACKGROUND

The Vertical Expandable Prosthetic Titanium Rib (VEPTR™; Synthes North America, West Chester, PA) reportedly controls spinal deformity associated with constrictive chest wall conditions.

QUESTIONS/PURPOSES

We asked whether spine-to-spine constructs using VEPTR™ instrumentation in combination with standard spinal instrumentation could be deployed to salvage failed rib-to-spine constructs used originally in patients with constricted chest walls and to primarily treat progressive spinal deformity without chest wall abnormalities.

PATIENTS AND METHODS

Fifty patients were treated with VEPTR™ constructs for thoracic insufficiency syndrome at our center between 2001 and 2007. Fourteen of these 50 patients had placement of a spine-to-spine construct using a VEPTR™ implant in combination with standard spinal implants and are the subject of this retrospective review. Five had prior rib-based VEPTR™ or growing implants with an average of two failures before this surgery. Radiographic variables, preceding treatment, complications, and changes in ambulatory status, were recorded. The minimum followup was 2 years (mean, 35 months; range, 2-4 years).

RESULTS

After an average of five expansions in these 14 patients, positive changes were recorded for Cobb angle, T1-S1 height, sagittal balance, and space available for the lung. Complications included two rod fractures, two superficial infections, and one deep infection with rod removal.

CONCLUSIONS

VEPTR™ instrumentation as a spine-to-spine growing-rod construct demonstrated ease of implantation and expansion, with complication rates similar to other reported devices. This study suggests growing constructs using VEPTR™ can be used with relatively few complications and extends the potential uses of this instrumentation system.

Age-related variations of leptin receptor expression in the growth plate of spine and limb: gender- and region-specific changes

Leptin is a potent growth-stimulating factor of bone. The effects of leptin on bone growth differ significantly between axial and appendicular regions. Gender differences of leptin function have also been suggested in normal pubertal development. To explore the mechanisms underlying these effects, we investigated the spatial and temporal expressions of the active form of the leptin receptor (Ob-Rb) in the tibial and spinal growth plates of the female and male rats during postnatal development. The 1-, 4-, 7-, 12- and 16-week age stages are representative for early life, puberty and early adulthood after puberty, respectively. Quantitative real-time PCR was used for Ob-Rb mRNA examination and comparison. The spatial location of Ob-Rb was determined by immunohistochemical analysis. There were gender- and region-specific differences in Ob-Rb mRNA expression in the growth plate. Mainly cytoplasm staining of Ob-Rb immunoreactivity was observed in the spinal and tibial growth plate chondrocytes of both genders. Spatial differences of region- and gender-related Ob-Rb expression were not observed. Ob-Rb immunoreactivity was detected in the resting, proliferative and prehypertrophic chondrocytes in early life stage and during puberty. After puberty, staining was mainly located in the late proliferative and hypertrophic chondrocytes. The results of Ob-Rb HSCORE analysis were similar to those obtained from quantitative real-time PCR. Our study indicated direct effects on the chondrocytes of the growth plate in different development stages. The region-specific expression patterns of Ob-Rb gene might be one possible reason for contrasting phenotypes in limb and spine. Different Ob-Rb expression patterns might partly contribute to age- and gender- related differences in trabecular bone mass.