Toshiaki Kotani

To investigate the effectiveness of incentive spirometry on respiratory motion in healthy subjects using cine breathing magnetic resonance imaging (MRI). Ten non-smoking healthy subjects without any history of respiratory disease were studied. Subjects were asked to perform pulmonary training using incentive spirometry every day for two weeks. To assess the effectiveness of this training, pulmonary function tests and cine breathing MRI were performed before starting pulmonary training and two weeks after its completion. After training, there were significant improvements in vital capacity (VC) from 3.58±0.8 L to 3.74±0.8 L and in %VC from 107.4±10.8 to 112.1±8.2. Significant changes were observed in the right diaphragm motion, right chest wall motion, and left chest wall motion, which were increased from 55.7±9.6 mm to 63.4±10.2 mm, from 15.6±6.1 mm to 23.4±10.4 mm, and from 16.3±7.6 mm to 22.0±9.8 mm, respectively. Two weeks of training using incentive spirometry provided improvements in pulmonary function and respiratory motion, which suggested that incentive spirometry may be a useful preoperative modality for improving pulmonary function during the perioperative period.

Migration of neurogenic spinal tumours is uncommon. However, such possible mobility should be kept in mind during surgery for neurogenic tumours whenever the lesion is not found at the anticipated level. Conventional static imaging techniques, such as myelography and MRI, have not documented dynamic motion of tumours. A 12-year-old boy was diagnosed with a neurogenic spinal tumour in the thoracolumbar region. To assess the migratory tendency of the tumour, cine MRI was performed to acquire dynamic images under postural change. Cine MRI showed that the tumour migrated up to the lower part of the T12 vertebra from the upper part of the L1 vertebra during a change in spinal posture from cervical flexion to extension. The tumour was completely removed and histological examination revealed the tumour to be an ependymoma. Cine MRI is useful for dynamically and non-invasively assessing the migratory tendency of spinal tumours.

Kotani T, et al. Asian Spine J. 2014 Jun;8(3):331-338. http://dx.doi.org/10.4184/asj.2014.8.3.331

Spinal implants are occasionally removed due to infection or soft tissue irritation secondary to prominence. Several studies have reported loss of scoliotic curve correction after implant removal. However, further review of the literature reveals no similar cases of rapid curve progression following implant removal in patients with adolescent idiopathic scoliosis (AIS) necessitating repeat posterior instrumented fusion. To describe a 15-year-old female AIS patient treated by posterior instrumented fusion, who developed unusual rapid coronal and sagittal curve progression after implant removal. Case report. Retrospective case report. A 15-year-old female with Lenke type 1A AIS underwent a successful posterior spinal fusion with instrumentation. She initially had no complications after surgery, but three years after instrumentation, her implants were removed due to pain secondary to implant prominence. Fifteen months after removal, the main thoracic curve increased, compared with radiographs taken before removal, from 29° to 57°. This development required the patient to undergo additional surgery, which involved multiple osteotomies and posterior reinstrumentation. We must acknowledge that a remarkable amount of progression can occur rapidly following implant removal in scoliotic patients. Taking this into consideration,we need to carefully explain to patients that removal of their implants entails a risk of progressive deformity and that they need to follow-up with their physician after implant removal.

Postoperative pneumothorax in posterior fusion using pedicle screws is uncommon, but the complication needs to be kept in mind. There are reports of a pseudopneumothorax resulting from artifacts. We report a unique case of a pseudopneumothorax in a patient with scoliosis, diagnosed using O-arm intraoperative computed tomography. The pseudopneumothorax, initially appearing on a chest radiograph, turned out to be an area of partial atelectasis at the lateral border of the right lower lobe. Spine surgeons and anesthesiologists must recheck images and maintain a high degree of suspicion for a pseudopneumothorax when the radiographic image during scoliosis surgery does not match the patient's condition.

Prospective trial of virtual endoscopy in spinal surgery. To investigate the utility of virtual endoscopy of the spine in conjunction with spinal surgery. Several studies have described clinical applications of virtual endoscopy to visualize the inside of the bronchi, paranasal sinus, stomach, small intestine, pancreatic duct, and bile duct, but, to date, no study has described the use of virtual endoscopy in the spine. Virtual endoscopy is a realistic 3-dimensional intraluminal simulation of tubular structures that is generated by postprocessing of computed tomographic data sets. Five patients with spinal disease were selected: 2 patients with degenerative disease, 2 patients with spinal deformity, and 1 patient with spinal injury. Virtual endoscopy software allows an observer to explore the spinal canal with a mouse, using multislice computed tomographic data. Our study found that virtual endoscopy of the spine has advantages compared with standard imaging methods because surgeons can noninvasively explore the spinal canal in all directions. Virtual endoscopy of the spine may be useful to surgeons for diagnosis, preoperative planning, and postoperative assessment by obviating the need to mentally construct a 3-dimensional picture of the spinal canal from 2-dimensional computed tomographic scans.

The motions of chest wall and diaphragm were measured in patients with scoliosis and healthy individuals using dynamic breathing magnetic resonance imaging. To investigate the motions of the chest wall and the diaphragm during deep breathing in patients with idiopathic scoliosis. Despite the central role of the respiratory motions in maintaining ventilation, it is difficult to measure and describe the motions because of the limited methods available. The kinematics of respiration in scoliosis have not yet been clarified. Dynamic fast spoiled gradient-recalled echo sequences were used for 18 patients with idiopathic scoliosis and 9 healthy individuals. The chest wall and diaphragm motions were evaluated using a cineloop view and a fusion display of maximal inspiratory and expiratory images. The data were analyzed quantitatively by measuring displacements. Respiratory chest wall movements were significantly restricted in patients with scoliosis, although the diaphragm motion was normal. An analysis of the fusion magnetic resonance displays superimposed with the maximal inspiratory and expiratory images facilitated the understanding of the abnormal respiratory motion in patients with scoliosis. There was some correlation between the values of respiratory motions and pulmonary function tests. The present technique is useful for assessing respiratory mechanisms dynamically and noninvasively. One of the distinguishing features of respiratory dysfunction in patients with scoliosis is their limited chest wall motion.

Three hundred and four girls with adolescent idiopathic scoliosis were investigated to determine if DNA polymorphisms in the vitamin D receptor (VDR), estrogen receptor (BR), and CYP17 gene were related to curve progression of idiopathic scoliosis. The results suggested that XbaJ site polymorphism in the ER gene was associated with curve progression. The Cobb's curve angle with genotype XX and Xx was statistically greater than that with genotype xx. The curve progression risk (approximately 5 degrees) was higher for genotype XX and Xx than for genotype xx. Furthermore, patients with genotype XX and Xx had a higher risk of receiving operative treatment than those with genotype xx. In conclusion, DNA analysis may predict curve progression, although other polymorphisms were not associated with curve severity.

The mechanical inefficiency during respiration in scoliosis remains unclear. To study the three-dimensional motion of the chest wall during deep breathing in healthy and scoliotic individuals. Three-dimensional chest wall motion during breathing was studied in 17 scoliotic patients (right thoracic curvature) and 9 healthy individuals. Measurements were performed using a Zebris CMS 70P system (Zebris Medizintechnik Gmbll, Isny, Germany) which analyzes the time delay of ultrasound pulses emitted from markers placed on the chest wall. Nine markers were attached on the upper, the middle and the lower chest wall. Subjects were seated on a chair and asked to breathe deeply and slowly with no elevation of the shoulders for one minute. The amplitudes were symmetric between the two sides in healthy individuals while scoliotic patients exhibited asymmetric chest wall motion. The amplitudes of the right convex side of the chest wall exhibited less motion than those of the left concave side, especially on the lower chest wall. Chest wall motion was asymmetric in the scoliotic patients with diminished motion of the right lower chest wall. This locally diminished ventilation may cause ventilation-perfusion inequality and result in hypoxemia.