Published papers

Study Design.Case-control study.Objective.To examine factors influencing cervical alignment after corrective surgery for adult patients with adolescent idiopathic scoliosis (AdIS)Summary of Background Data.Corrective surgery for spinal deformity influences postoperative cervical spinal alignment, but changes in the cervical alignment in adults with AdIS are scarcely reported.Methods.We retrospectively examined 85 patients with AdIS who underwent posterior corrective surgery for thoracic or lumbar major curve and were followed up for 2 years. Clinical characteristics, radiographic parameters, and health-related quality of life (HRQOL) were evaluated. Cervical deformity (CD) was defined as one of the following cases: (1) T1 tilt minus C2-C7 angle more than 20°, (2) C2-C7 SVA more than 40mm, (3) and C2-C7 angle less than-10°. Patients were divided into those with and without CD based on the defined criteria; statistically relevant factors were analyzed.Results.There were 19 patients in the postoperative CD group. The average age at the time of surgery was lower in the CD group (26.5 vs. 31.4). In the CD group, the average preoperative T1 tilt was smaller (1.1° vs. 12.5°), and the C2-C7 angle was kyphotic (-16.1° vs. 3.0°). The average kyphotic angle at thoracic spine (T5-T12) was lower in the CD group preoperatively (12.5° vs. 19.5°) and postoperatively (15.2° vs. 20.8°). HRQOL outcomes were comparable between the groups. Of the patients with preoperative CD, 51.5% (n=17) maintained their deformity at the final follow-up, and baseline C2-C7 angle was lower than those who converted to non-CD following surgery (n=16) (-17.0° vs.-10.3°).Conclusion.More than half of the patients with baseline CD maintained their cervical malalignment postoperatively. Patients with postoperative CD presented cervical kyphotic and thoracic hypokyphotic alignments before surgery. Because CD has the potential to lead to cervical degeneration, careful follow-up observation is necessary for these young patients.Level of Evidence: 3.

Study design: Retrospective chart audit. Objectives: This study investigated changes in sagittal alignment in adults after excision of thoracic spinal cord tumors without spinal fixation. Setting: Single-center study at an academic orthopedic department in Japan. Methods: We retrospectively reviewed records for 32 adults who underwent excision of thoracic spinal cord tumors by multilevel laminectomies without fixation. The participants were divided according to whether the tumor was in the upper (T1–4), middle (T5–8), or lower (T9–12) thoracic spine. We analyzed parameters such as age, sex, time in surgery and estimated blood loss, follow-up period, and preoperative and follow-up the Japanese Orthopaedic Association (JOA) scores and radiographs. Results: Postoperative T1-12 kyphotic changes did not correlate with age, the number of resected laminae, or preoperative T1-12 kyphosis. JOA recovery rates were similar regardless of the tumor location. Participants with tumors in the upper thoracic spine had significant postoperative increases in T1–4 kyphosis, T1 slope (p <.05, respectively). In contrast, there were no significant changes in alignment in participants with tumors in the middle or lower thoracic spine. Conclusion: Even without fixation, sagittal alignment did not change after surgery to excise tumors in the middle and lower thoracic spine, indicating that fixation may not be necessary when excising spinal cord tumors in this region. In contrast, postoperative kyphosis may increase when the tumor is in the upper thoracic spine.

Background: Some patients suffer from long-lasting symptoms after whiplash injury. However, there are few reports on the long-term changes in the cervical spine after whiplash injury using imaging tests. The purpose of this longitudinal study was to determine the changes on MRI of the cervical spine 20 years after whiplash injury, and to examine the relationships between changes in the cervical spine on MRI and changes in related clinical symptoms. Methods: Eighty-one subjects finally participated in this study (follow-up rate 16%). The mean follow-up duration was 21.7 years. All subjects filled out a questionnaire about their clinical symptoms. The MRI findings were assessed using numerical grading system applied in the original study. Statistic analyses were used to investigate whether the progression of each MRI finding was associated with the severity of neck pain, stiff shoulders, dizziness and tinnitus. Results: All subjects had complained of some clinical symptoms in the original study: 71 had neck pain, 53 stiff shoulders, and others. In the present study, 66 subjects (81.5%) complained of some clinical symptoms: 57 had stiff shoulders, 20 neck pain, and others. The progression of degeneration on MRI was observed in 95% of the subjects, with C4/5 and 5/6 being the most frequently involved levels. Changes in the severity of neck pain, stiff shoulders, dizziness and tinnitus over 20 years were not significantly associated with the progression of degenerative changes in the cervical spine on MRI. Conclusions: Twenty years after whiplash injury, 95% of the subjects showed a progression of degeneration in the cervical spine. The progression of the intervertebral disc degeneration in the cervical spine on MRI after whiplash injury was not significantly associated with changes in the severity of related clinical symptoms, indicating that the degenerative changes on MRI may reflect the physiological aging process rather than post-traumatic sequelae.

Background: Few studies have addressed in detail long-term degenerative changes in the cervical spine. In this study, we evaluated the progression of degenerative changes of the cervical spine that occurred over a 20-year period in an originally healthy cohort. We also sought to clarify the relationship between the progression of cervical degenerative changes and the development of clinical symptoms. Methods: For this prospective follow-up investigation, we recruited 193 subjects from an original cohort of 497 participants who had undergone magnetic resonance imaging (MRI) of the cervical spine between 1993 and 1996. The subjects were asked about the presence or absence of cervical spine-related symptoms. Degenerative changes of the cervical spine were assessed on MRI using an original numerical grading system. The relationship between the progression of degenerative changes and the onset of clinical symptoms was evaluated by logistic regression analysis. Results: Degeneration in the cervical spine was found to have progressed in 95% of the subjects during the 20-year period. The finding of a decrease in signal intensity of the intervertebral disc progressed in a relatively high proportion of the subjects in all age groups and occurred with similar frequency (around 60%) at all intervertebral disc levels. The rate of progression of other structural failures on MRI increased with age and was highest at C5-C6. The progression of foraminal stenosis was associated with the onset of upper-limb pain (odds ratio, 4.71 [95% confidence interval, 1.02 to 21.7]). Conclusions: A progression of degenerative changes in the cervical spine on MRI over the 20-year period was detected in nearly all subjects. There was no relationship between the progression of degeneration on MRI and the development of clinical symptoms, with the exception of an association found between foraminal stenosis and upper-limb pain. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

In diffuse idiopathic hyperostosis (DISH), the ankylosed spine becomes susceptible to spinal fractures and spinal cord injuries due to the long lever arms of the fractured segments that make the fracture extremely unstable. The aim of this retrospective multicenter study was to examine the differences in DISH-affected spine fractures according to fracture level. The data of 285 cases with fractures of DISH-ankylosed segments diagnosed through computed tomography (CT) imaging were studied and the characteristics of 84 cases with cervical fractures were compared to 201 cases with thoracolumbar fractures. Examination of the CT images revealed that cervical fracture cases were associated with ossification of the posterior longitudinal ligament and had fractures at the intervertebral disc level, while thoracolumbar fracture cases were associated with ankylosing of the posterior elements and had fractures at the vertebral body. Neurologically, cervical fracture cases had a higher ratio of spinal cord injury leading to higher mortality, while thoracolumbar fracture cases had lower rates of initial spinal cord injury. However, a subset of thoracolumbar fracture cases suffered from a delay in diagnosis that led to higher rates of delayed neurological deterioration. Some of these thoracolumbar fracture cases had no apparent injury episode but experienced severe neurological deterioration. The information provided by this study will hopefully aid in the education of patients with DISH and raise the awareness of clinicians to potential pitfalls in the assessment of DISH trauma patients.