This study aims to analyze the occurrence of wrong site spine surgery (WSSS) using a website questionnaire for the members of the Japanese Society for Spine Surgery and Related Research. Based on this study, we would like to discuss the possible preventive measures for WSSS. As a result, 80% of the respondents answered that they had experienced WSSS. The causes of WSSS were divided into the surgeon's and patient's oriented factors. Several preventive measures are considered, as follows.1) To confirm the surgical level by multiple surgeons, 2) to avoid hierarchical environment, 3) to put a marker at the spinous process and take X-ray, 4) to use fluoroscopy in cases with unclear X-ray, and 5) additionally, to check the spinal level before the patient is awakened from general anesthesia.

Introduction: Lateral lumbar interbody fusion (LLIF) with intraoperative navigation is used in corrective surgery for adult spinal deformity (ASD). However, there are few reports on the accuracy of navigation in this procedure. Therefore, we investigated the frequency of navigation errors and their risk factors in patients undergoing LLIF with intraoperative CT navigation for ASD.

Methods: Eighty-eight cases in which LLIF was performed under intraoperative navigation between three vertebrae from L2/3 to L4/5 with a reference frame fixed to the iliac crest for female ASD were included. A still image of the navigation was taken each time an intraoperative LLIF cage was inserted, and the deviation from the intraoperative CT was evaluated. The patient backgrounds of cases with and without misalignment were compared.

Results: There were 7/264 (2.6%) vertebrae with cage misalignment between navigation and CT images, all with navigation errors of <2 mm in coronal sections. The frequency of errors did not differ remarkably among the vertebrae. The group with navigation errors had remarkably lower bone density than the group without; there were no remarkable differences in other parameters.

Conclusions: Navigation errors result from misalignment between the reference frame and the surgical manipulation site. It is important to place the frame in a position that is strong and does not interfere with the operative field. In cases of spinal deformity, it is necessary to ensure that correction does not alter the positional relationship between the reference frame and the LLIF-operated vertebrae.

Introduction: In treating posttraumatic syringomyelia, subarachnoid-subarachnoid bypass (S-S bypass) surgery has been reported as not only a safe and effective surgical technique but also a safer physiological method owing to the reconstruction of cerebrospinal fluid flow. S-S bypass surgery is also performed for spinal arachnoid lesions with syringomyelia. This study aimed to investigate the results of S-S bypass surgery for spinal arachnoid lesions with syringomyelia and discuss its indications.

Methods: Forty-five patients (posttraumatic syringomyelia in 28 patients, arachnoid web in 6, and other spinal adhesive arachnoiditis in 11) who had progressive neurological symptoms and underwent S-S bypass surgery were included in this study. Clinical symptoms were assessed in terms of improvement, stabilization, or deterioration. The size of the cavity was assessed using preoperative and postoperative magnetic resonance imaging.

Results: Cavity reduction was observed in 36 of 45 patients (82%). Clinical symptoms improved in 32 patients (71%), Seven patients (16%) remained stable, whereas 6 deteriorated (13%).

Conclusions: S-S bypass surgery was effective in reducing the size of the cavity in most cases of spinal arachnoid lesions with syringomyelia.

Introduction: Dropped head syndrome caused by Parkinson's disease (PD) has a reported occurrence of 0.4-6%, but the difference in INEM (isolated neck extensor myopathy) concerning epidemiology, spinal alignment, and clinical futures is unclear.

Methods: Among 168 patients with DHS (41 males, 127 females, average age 74.1 years), we analyzed the differences in clinical findings among patients with INEM-DHS developed due to degenerative changes, patients with PD-DHS diagnosed with PD, and patients with PS-DHS diagnosed with drug-induced Parkinsonism.

Results: There were 116 cases (69.0%) with INEM-DHS, 13 (7.7%) with PD-DHS, and 6 (3.6%) with PS-DHS in addition to others. Females outnumbered males in all three groups. PD-DHS and PS-DHS had lower age onset than INEM-DHS. Three patients (1.8%) were diagnosed with PD at the initial examination for DHS, 4 (2.3%) developed DHS within 1 year from the diagnosis of PD, and 6 (3.6%) developed DHS in ≥1 year. Sagittal spinal alignment presented kyphotic deformity in PD-DHS and PS-DHS.

Conclusions: The complication rate of Parkinson's disease in patients with DHS was 7.7%, and 1.8% of the DHS cases were diagnosed with PD as a result of dropped head. Compared with INDM-DHS, PD-DHS was characterized by severe cervical kyphosis, and the clinical symptoms at onset were also severe, such as difficulty in walking with a continuous forward gaze. The prognosis tends to be poor.

Introduction: This study aimed to investigate the effect of early intervention of percutaneous balloon kyphoplasty (BKP) for osteoporotic vertebral fracture (OVF) on the quality of life (QOL) of elderly patients.

Methods: Patients were eligible for BKP for thoracolumbar OVF if any of the following conditions were met within 4 weeks of injury: 1) extensive intravertebral low intensity or localized high intensity change on T2-weighted images, 2) extensive intravertebral low intensity on T1-weighted images, 3) progressive intravertebral compression or kyphosis, or 4) ADL limitation on conservative therapy. The Numeric Pain Rating Scale, time to postoperative discharge, and EuroQol 5 dimensions 5-level Japanese version were compared between preoperative (including preinjury) values and postoperative values at 1, 6, and 12 months (p < 0.05).

Results: A total of 88 patients (16/72 male/female, mean age 80.7 years) completed the follow-up. Their bone density T score was −2.18. The mean time to BKP intervention after injury was 15.4 days, and postoperative discharge was 16.1 days. Postoperative Numeric Pain Rating Scale score improved significantly (p < 0.05). QOL at 1 month after surgery was similar to that before injury (p > 0.05) and was maintained until 12 months (p > 0.05). QOL of elderly patients aged >80 years was the same before injury and 1 month postoperatively (p > 0.05) and was maintained thereafter. However, in 13 patients (13/88, 14.8%) with postoperative secondary vertebral fractures, the EuroQol 5 dimensions 5-level score was significantly lower than before injury.

Conclusions: The impact of early intervention of BKP surgery for OVF on the QOL of the elderly was investigated. The results showed that even elderly patients aged >80 years were able to return to society early and maintain the same QOL as before the injury. However, postoperative secondary vertebral fractures affected the maintenance of QOL.

Introduction: This study aims to quantitatively evaluate degeneration of the intervertebral disc nucleus pulposus and vertebral cartilage endplates using MRI ultrashort TE, and to investigate the relationship between the two.

Methods: Intervertebral disc nucleus pulposus and vertebral cartilage endplates at L2/3, L3/4, and L4/5 levels were evaluated with 3.0 Tesla sagittal MRI images. Pfirrmann classification on T2-weighted sagittal image and endplate classification and score on T1-weighted image for visual evaluations of intervertebral disc nucleus pulposus and vertebral body cartilage endplates were quantitatively utilized, respectively. It was measured using T2 mapping via the ultrashort TE method for evaluation.

Results: The T2* value of the intervertebral disc nucleus pulposus decreased as the grade of the Pfirrmann classification progressed. In the end plate classification and score of the vertebral body cartilage endplates, the T2* value increased when degeneration progressed to Grades 2 and 3, but the T2* value decreased when degeneration progressed to Grades 4, 5, and 6. When the intervertebral disc nucleus pulposus T2* value is shortened, the vertebral body cartilage endplate T2* value is extended once, but then shortened.

Conclusions: A quantitative evaluation using the T2* value of the intervertebral disc and vertebral body cartilage endplate was reported. In the future, by proceeding with longitudinal studies using quantitative evaluation methods, it may be possible to elucidate which of the intervertebral disc and vertebral body cartilage endplate degeneration progresses first.

Introduction: Poor prognostic factors (PPF) on magnetic resonance imaging (MRI) (confined high intensity area or diffuse low intensity area in fractured vertebrae on T2-weighted MR images) predict delayed union after osteoporotic vertebral fractures (OVF). However, although we have treated OVF without PPF on MRI conservatively, there have been a few cases with residual low back pain. Therefore, the objectives of this study were to identify the risk factors of residual low back pain despite the absence of PPF on MRI, and to investigate clinical and radiographical characteristics during follow-up in such patients.

Methods: This retrospective cohort study included 55 patients (mean age 75.1 years, 47 females) who were followed up for over 6 months after conservative treatment for OVF. The cases with PPF on MRI or with cauda equina or nerve root compressed on MRI were excluded. The participants were divided into two groups: the residual low back pain group (VAS in low back pain ≥40 at 6 months; 16 patients) and the control group (39 patients). Evaluation items included radiographic parameters on dynamic films (sitting/supine lateral views) and whole spine X-ray, VAS in low back pain/buttock pain at the initial examination and 6 months after injury.

Results: Firstly, to identify the risk factors, univariate analysis showed significant differences in VAS in buttock pain at initial examination (p = 0.002), motion angle of fractured vertebrae (p = 0.047), TK (p = 0.046), and LL (p = 0.031). Multivariate analysis showed that VAS in buttock pain at first examination was an independent risk factor for residual low back pain 6 months after injury (adjusted odds ratio = 1.526, p = 0.019). Secondly, the patients in the residual low back pain group were significantly larger SVA at 6 months and more change in the height of anterior wall of fractured vertebrae in dynamic films at 6 months than those in the control group (p = 0.029 and p = 0.011, respectively). Moreover, the cases with confined high intensity area on T2-weighted images at 6 months were significantly more in the residual low back pain group than in the control group (p = 0.006).

Conclusions: The risk factor for residual low back pain after conservative treatment for OVF without PPF on MRI was buttock pain at the initial examination. The causes of residual low back pain were a larger SVA and delayed union of the fractured vertebrae. Patients with buttock pain at the initial examination should be carefully followed up, and surgical intervention such as vertebroplasty might be considered as necessary.

Introduction: We examined the factors that contribute to early improvement of symptoms after condoliase intradiscal injection therapy for lumbar disc herniation, including T2* values of the nucleus pulposus (NP) before the injection.

Methods: Consecutive 30 patients with lumber disc herniation were enrolled. The mean age was 58.2 years. Patients whose leg pain visual analog scale improved by >50% 1 week after treatment were defined the early improvement group, while those who exhibited improvement of <50% were defined the nonimprovement group.

Results: The disease duration tended to be shorter in the early improvement group and longer in the nonimprovement group (p = 0.08). Additionally, pretreatment T2* values of the NP were higher, and the T2* value changes before and after the treatment were larger in the early improvement group (p < 0.05). In the receiver operating characteristic analysis, the cutoff value for pretreatment intervertebral disc T2* values was 31.42 ms (sensitivity: 77.8%, specificity: 81.0%).

Conclusions: T2* value of the NP may be used as an index when deciding on intradiscal enzyme injection therapy for lumbar disc herniation.

Introduction: Previous report showed that history of preoperative radiotherapy was a risk factor for surgical site infection (SSI) in patients with spinal metastases, who underwent surgery of affected spine. This study aimed to clarify the correlation between the timing or dose of radiation and SSI.

Methods: Participants comprised 113 patients who underwent surgery for treating spinal metastases between January 2004 and December 2014. All patients had a history of preoperative radiotherapy for the affected spine. Patients who suffered SSI within 1 month after surgery were categorized as infected, and all others were categorized as noninfected. We evaluated and compared the two groups based on the period between preoperative radiotherapy and surgery (days), and total dose of radiation. We evaluated and compared the SSI rate among four groups, classified by the period, super-early (within 1 week), early (within 1 month), late (1 month-1 year), and super-late (>1 year).

Results: The median period did not differ between infected and noninfected groups (278 and 360 days). Total dose of radiation also did not differ. The rate of SSI did not differ in the super-early (7.7%), early (7.7%), late (8.6%), and super-late groups (9.6%).

Conclusions: The timing or dose of preoperative radiation therapy did not correlate with the risk of SSI in spinal metastasis patients.

Introduction: Locomotor examination has been reported to reveal postural abnormalities, including restricted forward bending in children, malalignment, and spinal deformity. This study aimed to clarify the relationship between thoracic kyphosis angle and cervical kyphosis angle and age-related changes in children with restricted forward bending.

Methods: A total of 105 cases of children with restricted forward bending (straight leg raise < 45°) were examined. Their average age was 11.2 (7-15) years, with 48 girls and 57 boys. For the evaluation, the thoracic kyphosis angle on whole spinal X-ray (AeroDR system) was examined by age and gender.

Results: The average thoracic kyphosis was 21.5°, and the average cervical lordosis was 2.8°. No gender-based difference was noted between both kyphosis angles. There was a correlation between the cervical kyphosis angle and the thoracic kyphosis angle, and cervical lordosis decreased with age. The group with a thoracic kyphosis angle of <22° had a significantly larger cervical kyphosis angle than the group with a thoracic spine kyphosis angle of ≥22°. In the cervical spine, 86% of the cases had a normal average lordosis of ≤17°, and in the thoracic spine, 97% of the cases had a normal average kyphosis of ≤35°. This tendency became remarkable with the increase in age.

Conclusions: The thoracic kyphosis angle and the cervical kyphosis angle are inversely correlated, and it may be possible to determine cervical kyphosis deformity by focusing on the decrease in thoracic kyphosis in children with restricted forward bending revealed upon locomotor examination.

Introduction: The rate of reoperation due to screw backout is high after posterior fusion (PSF) combined with percutaneous vertebroplasty using hydroxyapatite blocks (VPHA) for osteoporotic vertebral fractures at our institution. Between January 2018 and May 2021, VPHA+PSF treatment was performed in ten cases, and reoperation was performed in four. Eight cases are reported in detail and discussed with additional literature review.

Case Report: A 78-year-old male was injured in a fall, with a Th12 vertebral fracture. He was referred to our department approximately 3 months after the injury, and VPHA+PSF was performed at 3 above 2 below approximately 4 months after the injury. Preoperative lumbar spine bone mineral density was 64.4% young adult mean. The local kyphosis angle was −34° preoperatively but improved to −2°postoperatively. Symptoms of lower limb paralysis gradually improved, and he was able to walk with a walker. However, 1 month postoperatively, lateral X-ray of the lumbar spine showed the L1 vertebral fracture and lower screw backout, and the local kyphosis angle worsened to −22°. There was no worsening of paralysis of the lower limbs, but he had severe back pain and difficulty in walking; thus, reoperation was performed 2 months after primary surgery. After reoperation, his back pain improved, and he is now able to walk unassisted 1 year after the second surgery.

Conclusions: Although vertebral body-height reconstruction by VPHA is easy to perform, the power of the anterior column support can be weak. In cases in which the correction angle is large, reoperation may be required because fixation force cannot be maintained until the column is stabilized. We believe that it is necessary to avoid revision surgery after VPHA. Therefore, we must consider using augmentation techniques, such as sublaminar wiring or hooks, and another screw insertion method.