Reliability analysis of Cobb angle measurements of congenital scoliosis using X-ray and 3D-CT images.

PURPOSE: Therapeutic decisions for congenital scoliosis rely on Cobb angle measurements on consecutive radiographs. There have been no studies documenting the variability of measuring the Cobb angle using 3D-CT images in children with congenital scoliosis. The purpose of this study was to compare the reliability and measurement errors using X-ray images and those utilizing 3D-CT images. MATERIALS AND METHODS: The X-ray and 3D-CT images of 20 patients diagnosed with congenital scoliosis were used to assess the reliability of the digital 3D-CT images for the measurement of the Cobb angle. Thirteen observers performed the measurements, and each image was analyzed by each observer twice with a minimum interval of 1 week between measurements. The analysis of intraobserver variation was expressed as the mean absolute difference (MAD) and standard deviation (SD) between measurements and the intraclass correlation coefficient (IaCC) of the measurements. In addition, the interobserver variation was expressed as the MAD and interclass correlation coefficient (IeCC). RESULTS: The average MAD and SD was 4.5° and 3.2° by the X-ray method and 3.7° and 2.6° by the 3D-CT method. The intraobserver and interobserver intraclass ICCs were excellent in both methods (X-ray: IaCC 0.835-0.994 IeCC 0.847, 3D-CT: IaCC 0.819-0.996 IeCC 0.893). There was no significant MAD difference between X-ray and 3D-CT images in measuring each type of congenital scoliosis by each observer. CONCLUSIONS: Results of Cobb angle measurements in patients with congenital scoliosis using X-ray images in the frontal plane could be reproduced with almost the same measurement variance (3°-4° measurement error) using 3D-CT images. This suggests that X-ray images are clinically useful for assessing any type of congenital scoliosis about measuring the Cobb angle alone. However, since 3D-CT can provide more detailed images of the anterior and posterior components of malformed vertebrae, the volume of information that can be obtained by evaluating them has contributed greatly to the development of strategies for the surgical treatment of congenital scoliosis.

Management of Thoracic Insufficiency Syndrome in Patients With Jeune Syndrome Using the 70 mm Radius Vertical Expandable Prosthetic Titanium Rib.

BACKGROUND: Jeune syndrome (JS) often results in lethal thoracic insufficiency syndrome. Since 1991, vertical expandable prosthetic titanium rib Dynamic PosteroLateral Expansion Thoracoplasty was used at our institution for treatment of JS. This study assesses the safety and efficacy of this procedure. METHODS: Twenty-four JS patients were treated, 2 lost to follow-up, 17 with a minimum of 2-year follow-up retrospectively reviewed for clinical course: Assisted Ventilation Rate, respiratory rate, capillary blood gases, pulmonary function testings, and complications. Upright anteroposterior/lateral radiographs were measured for Cobb angle, kyphosis, lordosis, thoracic width, and thoracic/lumbar spinal height. Computed tomography scan lung volumes were obtained in 12 patients. RESULTS: Mean age at initial implant was 23 months (7 to 62 mo) with an average 8.4 years (2.3 to 15.6 y) of follow-up. Average chest width increased from 121 to 168 mm at follow-up (P<0.001). Preoperatively, 7/17 (41%) patients had scoliosis. The remainder developed scoliosis during treatment, 8 requiring additional implants. Thoracic and lumbar spinal height was normal preoperatively and stayed normal during treatment. Thoracic kyphosis/lumbar lordosis was stable. Average computed tomography scan total lung volumes increased 484 to 740 mm3 (P<0.001), and Assisted Ventilation Rate status tended to improve (P=0.07). Average forced vital capacity was 34% predicted at first test and 27% predicted at last follow-up. Early demise after surgery was common with multisystem disease. Mean respiratory rate decreased from 35 to 24 bpm at last follow-up (P<0.05). Survival rate of the 22 patients was 68%. Migration of the rib cradles/titanium slings occurred in 12 patients, superficial infections in 5 patients, deep infections in 4 patients, and wound dehiscence in 5 patients. Infection rate was 4.6% per procedure. CONCLUSIONS: The survival rate in JS with surgery was nearly 70% (compared with 70% to 80% mortality without treatment) with less ventilator dependence. Both C1 stenosis and scoliosis are common in JS. Spinal height in JS is normal. Complications are frequent, but tolerable in view of the clinical gains and increase in survival.

Vertical expandable prosthetic titanium rib as treatment of thoracic insufficiency syndrome in spondylocostal dysplasia.

BACKGROUND: Spondylocostal dysplasia (SCD) constitutes a heterogeneous patient group with multiple vertebral formations and segmentation defects of the entire spine, with asymmetric rib malformations. Respiratory failure has been reported in spondylocostal dysplasia secondary to thoracic insufficiency syndrome. The vertical expandable prosthetic titanium rib (VEPTR) reconstructs the chest wall to address the thoracic insufficiency seen in this patient population. The purpose of this study is to evaluate spinal deformity correction and respiratory function outcomes in a spondylocostal dysplasia population treated with VEPTR. METHODS: A cohort of 20 patients with spondylocostal dysplasia and 2-year follow-up were evaluated from a multicenter IDE study of 214 patients who had surgery with the VEPTR device. Data collected included gender, nonskeletal malformations, age at surgery, number of procedures, estimated blood loss, length of stay, and surgical time. Clinical and radiographic parameters were collected, and respiratory function was assessed. RESULTS: In 14 of 20 patients (70%), spinal deformity was controlled evidenced by a decrease of the initial Cobb coronal angle at last follow-up. Fourteen patients (70%) maintained their oxygen level throughout treatment. At preoperative and last evaluation, assisted ventilation rating (AVR) scores showed that 5 patients improved their level of ventilation and 14 patients maintained their AVR level at room air. One patient decreased his level from supplemental oxygen to night ventilation. Mean thoracic spinal length (growth) by year was 0.82 cm. No mortality occurred in this group of patients. CONCLUSIONS: VEPTR implantation in SCD allows continued thoracic spine growth while controlling progressive spine deformity. The improved AVR ratings after surgery suggest a beneficial effect on the natural history of TIS in this population. Mortality and complication rate seem acceptable in this high-risk population of SCD patients. LEVEL OF EVIDENCE: Therapeutic study, Level IV, (case series, no comparison group).

Expansion Thoracoplasty for Thoracic Insufficiency Syndrome Associated with Jarcho-Levin Syndrome.

INTRODUCTION: Although surgical treatment of spondylothoracic dysplasia (STD) is controversial, we have found that an expansion thoracoplasty using a Vertical Expandable Prosthetic Titanium Rib (VEPTR; DePuy Synthes) results in favorable outcomes, including 100% survivability (at an average follow-up of 6.2 years), increased thoracic spinal length, and decreased requirements for ventilation support. STEP 1 PREOPERATIVE PREPARATION: Make anteroposterior and lateral radiographs of the spine. STEP 2 POSITION THE PATIENT FOR THE PROCEDURE: The patient is placed in the prone position. STEP 3 THE INCISION: A curvilinear skin incision is made, starting proximally between the spine and the medial edge of the scapula. STEP 4 THE OSTEOTOMY: Perform the v-osteotomy. STEP 5 PLACEMENT OF THE VEPTR DEVICE: A number-4 VEPTR-I device is wedged in, starting laterally within the osteotomy sites, wedging the osteotomies apart, distracting the superior ribs proximally and the inferior ribs distally, lengthening the hemithorax, and stopping approximately at the posterior axillary line, when there is maximum stress on the superior and inferior ribs, to avoid fracture, and the lamina spreaders are then removed. STEP 6 WOUND CLOSURE: Insert drains and local anesthetic catheters and close the wound. STEP 7 EXPANSION AND REPLACEMENT PROCEDURES: Lengthen the devices with the standard VEPTR technique of limited 3-cm incisions every three to six months. RESULTS: VEPTR treatment in patients with STD is associated with increased thoracic spine height and reduced thoracic width-to-height ratio, suggesting a greater gain in height than in width. WHAT TO WATCH FOR: IndicationsContraindicationsPitfalls & Challenges.

Management of thoracic insufficiency syndrome in patients with Jarcho-Levin syndrome using VEPTRs (vertical expandable prosthetic titanium ribs).

BACKGROUND: Jarcho-Levin syndrome represents a spectrum of clinical and radiographic irregularities including abnormal vertebral segmentation or formation defects, rib deformities, and short-trunk dwarfism. These abnormalities cause reduced thoracic capacity for lung development, resulting in thoracic insufficiency syndrome. In the present study, we reviewed outcome measures related to scoliotic curve correction, thoracic growth, and respiratory function following VEPTR treatment in patients with Jarcho-Levin syndrome. METHODS: Twenty-nine patients with Jarcho-Levin syndrome, subclassified as spondylocostal dysostosis (SCD) or spondylothoracic dysplasia (STD), were treated with VEPTR expansion thoracoplasty and followed for at least two years since the initial implantation. Spinal and respiratory measures were collected prior to the initial VEPTR implantation, immediately after implantation, and at the most recent follow-up. RESULTS: VEPTR treatment was associated with improved clinical respiratory function and with increases in thoracic height (by 50% in the SCD group and 42% in the STD group) and thoracic width (by 37% in the SCD group and 28% in the STD group). VEPTR treatment resulted in scoliosis curve correction (improvement in the Cobb angle of 41% [22°] in the SCD group and 26% [3.7°] in the STD group) and in improved thoracic symmetry in patients with SCD. Patients with SCD displayed increased lumbar lordosis, and both groups of patients developed increased thoracic kyphosis approaching normal. CONCLUSIONS: VEPTR treatment improved thoracic symmetry, controlled spinal deformity, and was associated with improved clinical respiratory function.