Jack C. Y. Cheng

Adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) affects 1-3% of children in the at-risk population of those aged 10-16 years. The aetiopathogensis of this disorder remains unknown, with misinformation about its natural history. Non-surgical treatments are aimed to reduce the number of operations by preventing curve progression. Although bracing and physiotherapy are common treatments in much of the world, their effectiveness has never been rigorously assessed. Technological advances have much improved the ability of surgeons to safely correct the deformity while maintaining sagittal and coronal balance. However, we do not have long-term results of these changing surgical treatments. Much has yet to be learned about the general health, quality of life, and self-image of both treated and untreated patients with AIS.

A 10-year study of the changes in the pattern and treatment of 6,493 fractures.

A total of 6,493 fractures was studied from 6,389 children younger than 16 years admitted as inpatients to one center in a 10-year period. The boy-to-girl ratio increased from 1.4:1 in the infants to 4.9:1 in the adolescents. The most common fractures were the distal radius (20.2%), supracondylar fracture of the humerus (17.9%), forearm shaft (14.9%), and the tibial shaft (11.9%). A distinct age-specific fracture pattern also was found, with supracondylar fracture of the humerus being the most common fracture in the age 0- to 3-year (26.7%) and the 4- to 7-year (31.6%) groups and distal radius in the 8- to 11-year and the 12- to 16-year groups (24.3 and 25.7%, respectively). Although the overall pattern of the major fractures had not changed over the 10-year period, significant changes in the treatment pattern were observed. The closed-reduction and percutaneous pinning rates increased from 9.5 to 38.7% in fracture of the distal radius, 4.3 to 40% in the supracondylar humerus, and 1.8 to 22% in the forearm shaft. The changes in treatment pattern were also accompanied by a corresponding decrease in the open-reduction rate and hospital stay periods from <10% to 38% of patients being discharged within 1 day of admission in the 10-year period.

Infantile torticollis: a review of 624 cases.

We reviewed 624 cases of infantile torticollis in one centre over a period of 7 years. The incidence of torticollis was found to be 1.3% in Chinese children. Boy-to-girl ratio was 3:2. Obstetric histories of the mothers showed a total of 62.2% with difficult labour, breech deliveries, or caesarean section, and 6.04% had associated congenital anomalies. Of all the cases, 27.88% were found to be postural, 35.4% had torticollis that presented with sternomastoid tumor, and 36.7% presented with muscular torticollis alone. When limitation of neck range was considered, 36.7% had a passive rotation deficit > 15 degrees. In patients presenting in the early stages, 97% of all infantile torticollis cases resolved with conservative treatment, active stimulation, and a passive stretching program. For those responding to treatment, the mean treatment period was < 6 months for varying degrees of neck rotational deficit. Patients with cord-like muscular torticollis and a rotational > 30 degrees were more likely to need surgery. Presence of sternomastoid tumor alone was not found to increase the likelihood of surgery. Musculoskeletal sequelae after torticollis had resolved included intermittent head tilt and persistence of mild craniofacial asymmetry. We recommend continuous follow-up in cases of infantile torticollis, particularly in patients with progression of sternomastoid tumor to muscular torticollis.

Clinical determinants of the outcome of manual stretching in the treatment of congenital muscular torticollis in infants. A prospective study of eight hundred and twenty-one cases.

Background: The natural history of congenital muscular torticollis and the outcome of different treatment modalities have been poorly investigated, and the results of treatment have varied considerably. Methods: The main objective of this prospective study was to evaluate the outcomes of 821 consecutive patients with congenital muscular torticollis who were first seen when they were less than one year old, were treated with a standardized program of manual stretching, and were followed for a mean of 4.5 years. Before treatment, the patients were classified into one of three clinical groups: (1) palpable sternomastoid tumor, (2) muscular torticollis (thickening and tightness of the sternocleidomastoid muscle), and (3) postural torticollis (torticollis but no tightness or tumor). Results: Of the 821 patients, 452 (55%) had a sternomastoid tumor; 276 (34%), muscular torticollis; and ninety-three (11%), postural torticollis. Multivariate analysis of the outcomes showed that (1) the duration of treatment was significantly associated with the clinical group (p < 0.0001), a passive rotation deficit of the neck (p < 0.0001), involvement of the right side (p < 0.0001), difficulties with the birth (p < 0.009), and age at presentation (p < 0.0001); (2) the overall final assessment score was associated with the rotation deficit (p = 0.02), age at presentation (p = 0.014), and duration of treatment (p < 0.0001); and (3) subsequent surgical treatment was required by 8% (thirty-four) of the 452 patients in the sternomastoid tumor group compared with 3% (eight) of the 276 patients in the muscular torticollis group and 0% (none) of the ninety-three patients in the postural torticollis group. Conclusions: This large prospective study demonstrated that controlled manual stretching is safe and effective in the treatment of congenital muscular torticollis when a patient is seen before the age of one year. The most important factors that predict the outcome of manual stretching are the clinical group, the initial deficit in rotation of the neck, and the age of the patient at presentation. Surgical treatment is indicated when a patient has undergone at least six months of controlled manual stretching and has residual head tilt, deficits of passive rotation and lateral bending of the neck of >15°, a tight muscular band or tumor, and a poor outcome according to our special assessment chart.

Relative anterior spinal overgrowth in adolescent idiopathic scoliosis: RESULTS OF DISPROPORTIONATE ENDOCHONDRAL-MEMBRANOUS BONE GROWTH

There is no generally accepted scientific theory for the etiology of adolescent idiopathic scoliosis (AIS). As part of its mission to widen understanding of scoliosis etiology, the International Federated Body on Scoliosis Etiology (IBSE) introduced the electronic focus group (EFG) as a means of increasing debate on knowledge of important topics. This has been designated as an on-line Delphi discussion. The text for this EFG was written by Professor Jack Cheng and his colleagues who used whole spine magnetic resonance imaging (MRI) to re-investigate the relative anterior spinal overgrowth of progressive AIS in a cross-sectional study. The text is drawn from research carried out with his co-workers including measurement of the height of vertebral components anteriorly (vertebral body) and posteriorly (pedicles) in girls with AIS and in normal subjects. The findings confirm previous anatomical studies and support the consensus view that in patients with thoracic AIS there is relatively faster growth of anterior and slower growth of posterior elements of thoracic vertebrae. The disproportionate anteroposterior vertebral size is associated with severity of the scoliotic curves. In interpretating the findings they consider the Roth/Porter hypothesis of uncoupled neuro-osseous growth in the spine but point out that knowledge of normal vertebral growth supports the view that the scoliosis deformity in AIS is related to longitudinal vertebral body growth rather than growth of the canal. In the mechanical mechanism (pathomechanism) they implicitly adopt the concept of primary skeletal change as it affects the sagittal plane of the spine with anterior increments and posterior decrements of vertebral growth and, in the biological mechanism (pathogenesis) propose a novel histogenetic hypothesis of uncoupled endochondral-membranous bone formation. The latter is viewed as part of an ‘intrinsic abnormality of skeletal growth in patients with AIS which may be genetic’. The hypothesis that AIS girls have intrinsic anomalies (not abnormalities) of skeletal growth related to curve progression and involving genetic and/or environmental factors acting in early life is not original. While the findings of Professor Cheng and his colleagues have added MRI data to the field of relative anterior spinal overgrowth in AIS their interpretation engenders controversy. Three new hypotheses are proposed to interpret their findings: (1) hypoplasia of articular processes as a risk factor for AIS; (2) selection from the normal population to AIS involves anomalous vertebral morphology and soft tissue factors—this hypothesis may also apply to certain types of secondary scoliosis; and (3) a new method to predict the natural history of AIS curves by evaluating cerebro-spinal fluid (CSF) motion at the cranio–cervical junction. What is not controversial is the need for whole spine MRI research on subjects with non-idiopathic scoliosis.

A randomized double-blind controlled calcium supplementation trial, and bone height acquisition in children

There is limited information relating Ca intake to bone and height acquisition among Oriental children who consume little or even no milk. The present controlled study investigated the acquisition of bone mass and height of Chinese children with an initial Ca intake of approximately 567 mg/d who were supplemented to about 800 mg/d. Eighty-four 7-year-old Hong Kong Chinese children underwent an 18-month randomized, double-blind, controlled Ca-supplementation trial. The children were randomized to receive either 300 mg elemental Ca or a placebo tablet daily. Bone mass of the distal one-third radius was measured by single-photon absorptiometry, lumbar spine and femoral neck were determined using dual-energy X-ray absorptiometry. Measurements were repeated 6-monthly. Baseline serum 25-hydroxycholecalciferol concentration and physical activity were also assessed. Baseline Ca intakes of the study group and controls were respectively 571 (SD 326) and 563 (SD 337) mg/d. There were no significant differences in baseline serum 25-hydroxycholecalciferol concentration (P = 0.71) and physical activity (P = 0.36) between the study and control groups. After 18 months the study group had significantly greater increases in lumbar-spinal bone mineral content (20.9 v. 16.34%; P = 0.035), lumbar-spinal area (11.16 v. 8.71%; P = 0.049), and a moderately greater increment in areal bone mineral density of the radius (7.74 v. 6.00%; P = 0.081) when compared with the controls. The results confirm a positive effect of Ca on bone mass of the spine and radius but no effects on femoral-neck and height increase. A longer trial is warranted to confirm a positive Ca effect during childhood that may modify future peak bone mass.

Relative anterior spinal overgrowth in adolescent idiopathic scoliosis

There is no generally accepted scientific theory for the etiology of adolescent idiopathic scoliosis (AIS). As part of its mission to widen understanding of scoliosis etiology, the International Federated Body on Scoliosis Etiology (IBSE) introduced the electronic focus group (EFG) as a means of increasing debate on knowledge of important topics. This has been designated as an on-line Delphi discussion. The text for this EFG was written by Professor Jack Cheng and his colleagues who used whole spine magnetic resonance imaging (MRI) to re-investigate the relative anterior spinal overgrowth of progressive AIS in a cross-sectional study. The text is drawn from research carried out with his co-workers including measurement of the height of vertebral components anteriorly (vertebral body) and posteriorly (pedicles) in girls with AIS and in normal subjects. The findings confirm previous anatomical studies and support the consensus view that in patients with thoracic AIS there is relatively faster growth of anterior and slower growth of posterior elements of thoracic vertebrae. The disproportionate anteroposterior vertebral size is associated with severity of the scoliotic curves. In interpretating the findings they consider the Roth/Porter hypothesis of uncoupled neuro-osseous growth in the spine but point out that knowledge of normal vertebral growth supports the view that the scoliosis deformity in AIS is related to longitudinal vertebral body growth rather than growth of the canal. In the mechanical mechanism (pathomechanism) they implicitly adopt the concept of primary skeletal change as it affects the sagittal plane of the spine with anterior increments and posterior decrements of vertebral growth and, in the biological mechanism (pathogenesis) propose a novel histogenetic hypothesis of uncoupled endochondral-membranous bone formation. The latter is viewed as part of an ‘intrinsic abnormality of skeletal growth in patients with AIS which may be genetic’. The hypothesis that AIS girls have intrinsic anomalies (not abnormalities) of skeletal growth related to curve progression and involving genetic and/or environmental factors acting in early life is not original. While the findings of Professor Cheng and his colleagues have added MRI data to the field of relative anterior spinal overgrowth in AIS their interpretation engenders controversy. Three new hypotheses are proposed to interpret their findings: (1) hypoplasia of articular processes as a risk factor for AIS; (2) selection from the normal population to AIS involves anomalous vertebral morphology and soft tissue factors—this hypothesis may also apply to certain types of secondary scoliosis; and (3) a new method to predict the natural history of AIS curves by evaluating cerebro-spinal fluid (CSF) motion at the cranio–cervical junction. What is not controversial is the need for whole spine MRI research on subjects with non-idiopathic scoliosis.

Melatonin receptor 1B (MTNR1B) gene polymorphism is associated with the occurrence of adolescent idiopathic scoliosis.

Study Design. A genetic association study to comprehensively investigate variations of melatonin receptor 1B gene polymorphism by a set of tagging single nucleotide polymorphisms (tagSNPs) derived from the International Hapmap project. Objectives. To determine whether melatonin receptor 1B (MTNR1B) gene polymorphisms are associated with the predisposition and/or disease severity of adolescent idiopathic scoliosis (AIS). Summary of Background Data. Linkage studies suggested a genetic predisposition for AIS. In addition, evidence showed that AIS might be related to melatonin deficiency and dysfunction of melatonin signaling pathway. Locating in one of the chromosomal regions linked to AIS, MTNR1B gene is a potential candidate gene for AIS. Methods. This study was carried out in 2-stage case-control analysis: 1) initial screening (472 cases and 304 controls) and 2) separate replication test (342 cases and 347 controls) to confirm results in the screening. In the first screening stage, 5 tagSNPs were selected to cover most of the genetic variation in the MTNR1B gene. In the second stage, SNPs showing association in the screening stage were studied in a separate replication sample set to confirm the association. Genotyping was performed by PCR-RFLP. Results. The first stage showed a putative association between rs4753426 and AIS, which was confirmed in the replication sample set. By meta-analysis, the frequency of C allele of this SNP locating in the promoter was significantly higher in the cases than controls (P = 0.006 aftermeta-analysis). Subjects with the CC genotype had an odds ratio of 1.29 for AIS. Another SNP rs741837 in promoter region, being moderate linkage disequilibrium with rs4753426, was also marginally associated with AIS. Conclusion. Polymorphisms of the promoter of MTNR1B gene were associated with AIS, but not with the curve severity in AIS patients. This suggested that MTNR1B was an AIS predisposition gene.

Abnormal peri-pubertal anthropometric measurements and growth pattern in adolescent idiopathic scoliosis : a study of 598 patients

Study Design. A cross-sectional study of anthropometric parameters in adolescent idiopathic scoliosis (AIS). Objective. To compare anthropometric parameters and growth pattern of AIS girls versus normal controls during peri-puberty. Summary of Background Data. Abnormal pattern of growth has been reported in AIS patients. The sequential changes of growth and the correlation with curve severity have not been properly studied. Materials and Methods. Five hundred ninety-eight AIS girls and 307 healthy girls entered the study. Weight, height, body mass index (BMI), arm span, sitting height, and leg length were determined using standard techniques. Height and sitting height were adjusted by using the greatest Cobb angle to correct for spinal deformity (Bjure’s formula). Puberty was graded by Tanner’s staging. Results. AIS girls had significantly shorter height (P = 0.001), corrected height (P = 0.005), arm span (P = 0.022), sitting height (P = 0.005) and leg length (P = 0.004) than the controls at pubertal stage I. From pubertal stages II through V, corrected height (P ≤ 0.033) and arm span (P ≤ 0.038) were significantly longer in the AIS than controls. Corrected sitting height was also longer in AIS from stages II through IV (P ≤ 0.043). Furthermore, BMI of AIS was significantly lower than that of controls from stages II through IV (P ≤ 0.038). In addition, significant correlations of the curve severity versus weight, BMI, and arm span were also found (P ≤ 0.048). Conclusions. Various body segmental lengths were initially significantly shorter in AIS before puberty. However, after the onset of puberty, significantly longer corrected height, arm span, and various body segments were found. And there were significant correlations between anthropometric parameters and the scoliotic curve severity. Results of this large-scale study revealed the presence of abnormal growth in AIS patients during peripubertal development.

The Chinese Visible Human (CVH) datasets incorporate technical and imaging advances on earlier digital humans

We report the availability of a digitized Chinese male and a digitzed Chinese female typical of the population and with no obvious abnormalities. The embalming and milling procedures incorporate three technical improvements over earlier digitized cadavers. Vascular perfusion with coloured gelatin was performed to facilitate blood vessel identification. Embalmed cadavers were embedded in gelatin and cryosectioned whole so as to avoid section loss resulting from cutting the body into smaller pieces. Milling performed at −25 °C prevented small structures (e.g. teeth, concha nasalis and articular cartilage) from falling off from the milling surface. The male image set (.tiff images each of 36 Mb) has a section resolution of 3072 × 2048 pixels (∼170 µm, the accompanying magnetic resonance imaging and computer tomography data have a resolution of 512 × 512, i.e. ∼440 µm). The Chinese Visible Human male and female datasets are available at http://www.chinesevisiblehuman.com. (The male is 90.65 Gb and female 131.04 Gb). MPEG videos of direct records of real‐time volume rendering are at: http://www.cse.cuhk.edu.hk/~crc