Tetsuharu Nemoto

Long-term clinical outcomes of surgery for adolescent idiopathic scoliosis 21 to 41 years later.

Study Design. A case control study. Objective. To determine the clinical outcome of middle-aged patients surgically treated for adolescent idiopathic scoliosis and to compare their outcomes with assessments of age- and sex-matched healthy controls. Summary of Background Data. Several long-term follow-up studies have been published on the clinical outcomes of surgical treatment for adolescent idiopathic scoliosis in patients who have reached their 20s or 30s. However, clinical outcomes in patients who have reached middle age remain unknown. Methods. This study included 256 patients surgically treated for adolescent idiopathic scoliosis (AIS) between 1968 and 1988. The Scoliosis Research Society Patient Questionnaire (SRS-22) and Roland-Morris Disability Questionnaire (RDQ) were used for evaluating long-term clinical outcomes. Sixty-six (25.8%; 62 females, 4 males; mean age, 46.0 years [range 34–56]) of the 256 patients responded to the questionnaires. The mean follow-up period was 31.5 (range 21–41) years. Seventy-six healthy age- and sex-matched individuals with neither a history of spinal surgery nor scoliosis were selected as a control (CTR) group. Results. On the basis of the SRS-22 responses, AIS patients had significantly decreased function (AIS: 4.3 ± 0.6, CTR: 4.7 ± 0.5, P < 0.01) and decreased self-image (AIS: 3.0 ± 0.8, CTR: 3.7 ± 0.5, P < 0.01) in comparison with the controls, but the 2 groups were similar with respect to pain (AIS: 4.3 ± 0.6, CTR: 4.2 ± 0.5, P = 0.14) and mental health (AIS: 3.9 ± 0.9, CTR: 3.7 ± 0.7, P = 0.14). The RDQ responses indicated that low back pain was not significantly increased in the AIS group compared with the CTR group (AIS: 1.8 ± 3.5, CTR: 1.4 ± 3.1, P = 0.36). Conclusion. Surgery had no demonstrable adverse effects on pain or mental health in these middle-aged AIS patients 21–41 years after surgery, although the AIS patients did have significantly lower function and lower self-image than the controls.

Accuracy of Pedicle Screw Placement in Scoliosis Surgery: A Comparison between Conventional Computed Tomography-Based and O-Arm-Based Navigation Techniques.

Study Design Retrospective study. Purpose We compared the accuracy of O-arm-based navigation with computed tomography (CT)-based navigation in scoliotic surgery. Overview of Literature No previous reports comparing the results of O-arm-based navigation with conventional CT-based navigation in scoliotic surgery have been published. Methods A total of 222 pedicle screws were implanted in 29 patients using CT-based navigation (group C) and 416 screws were implanted in 32 patients using O-arm-based navigation (group O). Postoperative CT was performed to assess the screw accuracy, using the established Neo classification (grade 0: no perforation, grade 1: perforation <2 mm, grade 2: perforation ≥2 and <4, and grade 3: perforation ≥4 mm). Results In group C, 188 (84.7%) of the 222 pedicle screw placements were categorized as grade 0, 23 (10.4%) were grade 1, 11 (5.0%) were grade 2, and 0 were grade 3. In group O, 351 (84.4%) of the 416 pedicle screw placements were categorized as grade 0, 52 (12.5%) were grade 1, 13 (3.1%) were grade 2, and 0 were grade 3. Statistical analysis showed no significant difference in the prevalence of grade 2.3 perforations between groups C and O. The time to position one screw, including registration, was 10.9±3.2 minutes in group C, but was significantly decreased to 5.4±1.1 minutes in group O. Conclusions O-arm-based navigation facilitates pedicle screw insertion as accurately as conventional CT-based navigation. The use of O-arm-based navigation successfully reduced the time, demonstrating advantages in the safety and accuracy of pedicle screw placement for scoliotic surgery.

Health-related quality of life and low back pain of patients surgically treated for scoliosis after 21 years or more of follow-up: comparison among nonidiopathic scoliosis, idiopathic scoliosis, and healthy subjects.

Study Design. A case-control study. Objective. To compare health-related quality of life and low back pain of healthy subjects with those of patients with nonidiopathic scoliosis (non-IS) and idiopathic scoliosis (IS) 21 years or more after surgery. Summary of Background Data. There have been a very small number of reports on long-term results of surgery for non-IS. There have not been any reports that compare non-IS, IS, and healthy subjects. Methods. The subjects with scoliosis were 602 patients who had undergone surgery between 1968 and 1988. The Scoliosis Research Society Patient Questionnaire (SRS-22), Roland-Morris Disability Questionnaire (RDQ), and our institutions original questionnaire were used for evaluating long-term clinical outcomes. The 136 respondents consisted of 56 patients with non-IS (non-IS group) and 80 patients with IS (IS group). The control group (CTR group) consisted of 80 healthy volunteers who were age- and body mass index–matched to the scoliosis groups. Results. In the SRS-22, the 3 groups had no significant differences in pain and mental health. For function and self-image, the non-IS group and the IS group had a significantly lower score than the CTR group. In the RDQ, the non-IS group had significantly more severe low back pain than the CTR group. There was no significant difference in low back pain between the non-IS group and IS group or between the IS group and CTR group. The non-IS group had a significantly lower marriage rate than the IS and CTR groups. Conclusion. The patients with non-IS and IS had similar health-related quality of life and low back pain. The patients with non-IS were found to have lower function and self-image in the SRS-22 questionnaire and more severe low back pain in the RDQ than healthy subjects. The patients with non-IS had a significantly lower marriage rate than the other 2 groups.

Inhibition of nitric oxide synthesis accelerates the recovery of polysynapitc reflex potentials after transient spinal cord ischemia in cats

Abstract Nitric Oxide (NO) has been implicated as a mediator of neuronal injury in vascular stroke. On the other hand, NO is suggested to play a neuroprotective role by increasing blood flow during cerebral ischemia. In order to evaluate the role of NO in the spinal cord ischemia, effects of nitric oxide synthase (NOS) inhibition on the recovery of reflex potentials after a transient spinal cord ischemia were examined in urethane-chloralose anesthetized spinal cats. Spinal cord ischemia was produced by occlusion of the thoracic aorta and the both internal mammary arteries for 10min. Regional blood flow (RBF) in the spinal cord was continuously measured with a laser-Doppler flow meter. The monosynaptic (MSR) and polysynaptic reflex (PSR) potentials elicited by electrical stimulation of the tibial nerve, were recorded from the L7 or S1 ventral root. The recovery process of spinal reflex potentials was reproducible when the oclusion was repeated twice at an interval of 120min. Pretreatment with NG-monomethyl-l-arginine (l-NMMA, 10mg/kg), a NOS inhibitor significantly accelerated the recovery of PSR potentials after spinal cord ischemia. The accelerating effect of l-NMMA on the recovery of PSR potentials was abolished by co-administration of l-arginine (1mg/kg/min) but not by that of d-arginine (1mg/kg/min). l-NMMA failed to improve RBF in the spinal cord during ischemia and reperfusion. Nitroprusside (10μg/kg/min), a NO donor, retarded the recovery of PSR potentials after spinal cord ischemia. These results suggest that NO production has a significant influence on the functional recovery after transient spinal cord ischemia.

Effects of lipo-prostaglandin E1 on blood flow and oxygen pressure in lumbo-sacral nerve roots

Lipo-prostaglandin E1 (lipo-PGE1) is reported to be effective in the treatment of intermittent neurogenic claudication associated with lumbar spinal stenosis. However, the underlying mechanisms by which lipo-PGE1 improves the neurological symptoms have not been fully clarified. We examined the effects of lipo-PGE1 on blood flow and oxygen pressure in the lumbar nerve roots in cats and in patients with lumbar spinal stenosis. In anesthetized cats, blood flow and oxygen pressure in the L7 nerve root were measured with a laser-Doppler flowmeter and a polarographic oxygen monitor, respectively. Lipo-PGE1 (0.075 and 0.15μg/kg, i.v.) significantly increased blood flow and oxygen pressure in the nerve roots, following transient decreases. When the dural tube was compressed by a balloon at the L6 level, lipo-PGE1 (0.15 μg/kg) significantly increased blood flow and oxygen pressure in the nerve roots. Lipo-PGE1 also increased the intraoperative nerve-root blood flow in seven of ten patients with lumbar spinal stenosis. The results suggest that one of the favorable effects of lipo-PGE1 on neurogenic claudication is to increase nerve-root blood flow and oxygen pressure.

Effects of nicorandil on the recovery of reflex potentials after spinal cord ischaemia in cats

1 The pathophysiological significance of ATP‐sensitive K+ (KATP) channels in the central nervous system is not fully understood. In this study the effects of nicorandil (a hybrid vasodilator having a dual mechanism of action as a K+ channel opener and a nitrate) on the recovery of the spinal cord reflex potentials after spinal cord ischaemia were examined and compared with those of pinacidil and nitroprusside in anaesthetized spinal cats 2 Spinal cord ischaemia was produced by occlusion of the thoracic aorta and the bilateral internal mammary arteries for 10 min. Regional blood flow in the spinal cord was continuously measured with a laser‐Doppler flow meter. The monosynaptic (MSR) and polysynaptic reflex (PSR) potentials, elicited by electrical stimulation of the tibial nerve, were recorded from the lumbo‐sacral ventral root. The recovery process of spinal reflex potentials was reproducible when the occlusion was repeated twice at an interval of 120 min 3 Pretreatment with nicorandil (30–100 μg kg−1) accelerated the recovery of PSR potentials after spinal cord ischaemia. Such an accelerating effect on the recovery of PSR potentials was also shared by pinacidil (100 μg kg−1), another K+ channel opener. In addition, the accelerating effect of nicorandil (100 μg kg−1) on the recovery of PSR potentials was abolished by co‐administration of glibenclamide (3 mg kg−1), a sulphonylurea KATP channel blocker. Nitroprusside (8 μg kg−1 min−1) retarded rather than improved the recovery of PSR potentials after spinal cord ischaemia. AH of these drugs failed to improve the spinal cord blood flow during ischaemia and reperfusion 4 These results suggest that nicorandil promotes the recovery of polysynaptic reflex potentials after spinal cord ischaemia by opening the KATP channels of neurones rather than by increasing local blood flow. K+ channel openers may exert a salutary effect on the functional recovery of the ischaemic spinal cord.

Effects of Incentive Spirometry on Respiratory Motion in Healthy Subjects Using Cine Breathing Magnetic Resonance Imaging

Objective To investigate the effectiveness of incentive spirometry on respiratory motion in healthy subjects using cine breathing magnetic resonance imaging (MRI). Methods 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. Results 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. Conclusion 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.

Virtual endoscopic imaging of the spine.

Study Design. Prospective trial of virtual endoscopy in spinal surgery. Objective. To investigate the utility of virtual endoscopy of the spine in conjunction with spinal surgery. Summary of Background Data. 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. Methods. 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. Results. 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. Conclusion. 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.