The Utility and Feasibility of Smart Glasses in Spine Surgery: Minimizing Radiation Exposure During Percutaneous Pedicle Screw Insertion.

OBJECTIVE: Spine surgeons are often at risk of radiation exposure due to intraoperative fluoroscopy, leading to health concerns such as carcinogenesis. This is due to the increasing use of percutaneous pedicle screw (PPS) in spinal surgeries, resulting from the widespread adoption of minimally invasive spine stabilization. This study aimed to elucidate the effectiveness of smart glasses (SG) in PPS insertion under fluoroscopy. METHODS: SG were used as an alternative screen for fluoroscopic images. Operators A (2-year experience in spine surgery) and B (9-year experience) inserted the PPS into the bilateral L1-5 pedicles of the lumbar model bone under fluoroscopic guidance, repeating this procedure twice with and without SG (groups SG and N-SG, respectively). Each vertebral body's insertion time, radiation dose, and radiation exposure time were measured, and the deviation in screw trajectories was evaluated. RESULTS: The groups SG and N-SG showed no significant difference in insertion time for the overall procedure and each operator. However, group SG had a significantly shorter radiation exposure time than group N-SG for the overall procedure (109.1 ± 43.5 seconds vs. 150.9 ± 38.7 seconds; p = 0.003) and operator A (100.0 ± 29.0 seconds vs. 157.9 ± 42.8 seconds; p = 0.003). The radiation dose was also significantly lower in group SG than in group N-SG for the overall procedure (1.3 ± 0.6 mGy vs. 1.7 ± 0.5 mGy; p = 0.023) and operator A (1.2 ± 0.4 mGy vs. 1.8 ± 0.5 mGy; p = 0.013). The 2 groups showed no significant difference in screw deviation. CONCLUSION: The application of SG in fluoroscopic imaging for PPS insertion holds potential as a useful method for reducing radiation exposure.

Clinical Features and Therapeutic Process of Sacral Fatigue Fractures in Adolescents.

BACKGROUND: Sacral fatigue fractures are a rare injury but should be considered as a differential diagnosis for low back and buttock pain in young adults. Collective reports are limited, most of which have focused on long-distance runners. PURPOSE: To investigate the characteristics of sacral fatigue fractures in adolescents. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We analyzed patient background characteristics, physical examination and imaging findings, and treatment courses of those diagnosed with sacral fatigue fractures using magnetic resonance imaging. RESULTS: Among 34 patients with sacral fatigue fractures, 15 and 19 were male and female patients, respectively, with an age range of 11 to 19 years (mean age, 15.0 years). Almost all patients were athletes, and 29 patients performed their sport ≥5 times a week. Long-distance runners were the most commonly affected, comprising 7 patients, and participants in other common sports such as baseball (6 patients), basketball (4 patients), and soccer (3 patients) were also affected. Physical examination revealed tension sign (Lasègue test) on the affected side in 6 patients and tight hamstrings in 24 patients. Imaging findings included 18 patients with right-side involvement, 12 with left-side involvement, and 4 with involvement on both sides. In 11 patients, spina bifida occulta was observed at S1 and 8 patients had a history of lumbar spondylolysis with 4 patients having concurrent sacral fatigue fractures. Physical therapy was performed concurrently with the cessation of exercise, and return to exercise was permitted if the pain had been relieved after 1 month. All patients returned to sports at a median of 48 days (range, 20-226 days) after symptom onset. However, 2 patients experienced recurrence (1 patient on the ipsilateral side and 1 patient on the contralateral side). CONCLUSION: Sacral stress fractures are not limited to long-distance runners in this population and can manifest as lower back pain or buttock pain in athletes participating in a variety of sports. Although the course of treatment was generally good, the possibility of recurrence must always be considered.

Clinical Characteristics, Surgical Outcomes, and Risk Factors for Emergency Surgery in Patients With Spinal Metastases: A Prospective Cohort Study.

OBJECTIVE: To elucidate the patient characteristics and outcomes of emergency surgery for spinal metastases and identify risk factors for emergency surgery. METHODS: We prospectively analyzed 216 patients with spinal metastases who underwent palliative surgery from 2015 to 2020. The Eastern Cooperative Oncology Group performance status, Barthel index, EuroQol-5 dimension (EQ5D), and neurological function were assessed at surgery and at 1, 3, and 6 months postoperatively. Multivariate analysis was performed to identify risk factors for emergency surgery. RESULTS: In total, 146 patients underwent nonemergency surgery and 70 patients underwent emergency surgery within 48 hours of diagnosis of a surgical indication. After propensity score matching, we compared 61 patients each who underwent nonemergency and emergency surgery. Regardless of matching, the median performance status and the mean Barthel index and EQ5D score showed a tendency toward worse outcomes in the emergency than nonemergency group both preoperatively and 1 month postoperatively, although the surgery greatly improved these values in both groups. The median survival time tended to be shorter in the emergency than nonemergency group. The multivariate analysis showed that lesions located at T3-10 (p = 0.002; odds ratio [OR], 2.92; 95% confidence interval [CI], 1.48-5.75) and Frankel grades A-C (p < 0.001; OR, 4.91; 95% CI, 2.45-9.86) were independent risk factors for emergency surgery. CONCLUSION: Among patients with spinal metastases, preoperative and postoperative subjective health values and postoperative survival are poorer in emergency than nonemergency surgery. Close attention to patients with T3-10 metastases is required to avoid poor outcomes after emergency surgery.

Imaging Characteristics of Non-Rheumatoid Arthritis Patients With Retro-Odontoid Pseudotumor: A Multicenter Case-Control Study.

STUDY DESIGN: Multicenter case-control study. OBJECTIVE: To identify imaging characteristics of the cervical spine in patients with retro-odontoid pseudotumor (ROP) without rheumatoid arthritis (RA) and determine the pathogenesis of ROP. SUMMARY OF BACKGROUND DATA: ROP results from proliferative changes in the soft tissue of the atlantoaxial junction surrounding the region of the transverse ligament, and is commonly seen in RA patients. However, the pathogenesis of ROP caused by mechanical instability of the upper cervical spine in patients without RA is yet to be explained. METHODS: We collected imaging data (preoperative radiographs, magnetic resonance imaging [MRI], and computed tomography [CT]) of patients who underwent surgery between April 2011 and March 2022 at the three university hospitals for ROP (cases) and cervical spondylotic myelopathy (as age, sex, and institution matched controls). The two groups were compared for different parameters on cervical dynamic radiographs, MRI, and CT. RESULTS: The ROP group consisted of 42 patients, and the control group comprised 168 patients. C2-C7 range of motion was significantly smaller in the ROP group (25.8 ± 2.6°) compared to the control group (33.0 ± 1.0°). C2-C7 sagittal vertical axis was significantly larger in the ROP group than the control group (39.3 ± 3.6 mm versus 32.2 ± 1.3 mm). MRI and CT assessment showed progressive degeneration at all intervertebral levels in the ROP group. A significant positive correlation was observed between the thickness of the soft tissue posterior to the dental process and the atlantodental interval in the flexion position (r = 0.501). CONCLUSION: The development of ROP was associated with degeneration of facet joints and intervertebral discs in the middle and lower cervical spine. Our findings suggest that decreased mobility of the middle and lower cervical spine may cause instability in the upper cervical spine, leading to the formation of ROP.

Rate and Duration of Bone Union for Conservative Treatment in Pediatric Lumbar Spondylolysis.

STUDY DESIGN: Retrospective case series. OBJECTIVE: To report the detailed bone fusion rates and duration of treatment in unilateral and bilateral cases of pediatric lumbar spondylolysis (LS). SUMMARY OF BACKGROUND DATA: Early diagnosis and optimal conservative management for LS are crucial for achieving bony healing without surgery. However, existing research on the conservative treatment of pediatric LS, particularly regarding bone union rates and treatment duration for each stage of bilateral spondylolysis, is limited. METHODS: We retrospectively analyzed 590 pediatric patients (522 boys and 68 girls) under 18 years of age diagnosed with LS and treated conservatively from 2015 to 2021. Diagnosis was based on computed tomography scans and magnetic resonance imaging findings, with stages classified as very early, early, progressive, or terminal. Patient background, sports history, level and stage of spondylolysis, presence of spina bifida occulta, bone union rate, duration of conservative treatment, and recurrence rate were retrospectively analyzed. RESULTS: The overall bone union rate was 81.9%, with a mean conservative treatment duration of 53.7 days. Unilateral LS cases showed decreased bone union rates with stage advancement (very early; 98.2%, early; 96.0%, progressive; 64.3%). Bilateral LS cases with progressive or terminal stage demonstrated low bone union rates (very early/very early; 100%, early/very early; 94.1%, progressive/very early; 66.7%, early/early; 82.9%, progressive/early; 32.3%, progressive/progressive; 23.7%, very early/terminal; 0%, early/terminal; 50.0%, progressive/terminal; 11.1%). The duration of conservative treatment extended as the stage of the main and contralateral lesions progressed, ranging from 39.1 days (very early/none) to 105 days (progressive/terminal). Recurrence rate after bone fusion was 16.6%, with no differences based on lesion stage. CONCLUSION: In this series of 590 patients, conservative treatment yielded high bone union rates for pediatric LS. However, union rates decreased with stage advancement, especially in bilateral cases. These findings provide valuable insights for prognosticating natural history and outcome regarding LS treatment, bone union and return to activity.

Clinical Characteristics and Surgical Outcomes of Metastatic Spine Tumors in the Very Elderly: A Prospective Cohort Study in a Super-Aged Society.

The number of advanced-age patients with spinal metastases is rising. This study was performed to clarify the characteristics and surgical outcomes of spinal metastases in advanced-age patients. We prospectively analyzed 216 patients with spinal metastases from 2015 to 2020 and divided them into three age groups: <70 years (n = 119), 70-79 years (n = 73), and ≥80 years (n = 24). Although there were no significant intergroup differences in preoperative characteristics and surgery-related factors except for age, patients aged ≥80 years tended to have a worse performance status (PS), Barthel index, and EuroQol-5 dimension (EQ-5D) before and after surgery than the other two groups. Although the median PS, mean Barthel index and mean EQ-5D greatly improved postoperatively in each group, the median PS and mean Barthel index at 6 months and the mean EQ-5D at 1 month postoperatively were significantly poorer in the ≥80-year group than the 70-79-year group. The rates of postoperative complications and re-deterioration of the EQ-5D were significantly higher in the oldest group than in the other two groups. Although surgery for spinal metastases improved the PS, Barthel index, and EQ-5D regardless of age, clinicians should be aware of the poorer outcomes and higher complication rates in advanced-age patients.

Anti-Inflammatory Effects of Adiponectin Receptor Agonist AdipoRon against Intervertebral Disc Degeneration.

Adiponectin, a hormone secreted by adipocytes, has anti-inflammatory effects and is involved in various physiological and pathological processes such as obesity, inflammatory diseases, and cartilage diseases. However, the function of adiponectin in intervertebral disc (IVD) degeneration is not well understood. This study aimed to elucidate the effects of AdipoRon, an agonist of adiponectin receptor, on human IVD nucleus pulposus (NP) cells, using a three-dimensional in vitro culturing system. This study also aimed to elucidate the effects of AdipoRon on rat tail IVD tissues using an in vivo puncture-induced IVD degeneration model. Analysis using quantitative polymerase chain reaction demonstrated the downregulation of gene expression of proinflammatory and catabolic factors by interleukin (IL)-1ß (10 ng/mL) in human IVD NP cells treated with AdipoRon (2 µM). Furthermore, western blotting showed AdipoRon-induced suppression of p65 phosphorylation (p < 0.01) under IL-1ß stimulation in the adenosine monophosphate-activated protein kinase (AMPK) pathway. Intradiscal administration of AdipoRon was effective in alleviating the radiologic height loss induced by annular puncture of rat tail IVD, histomorphological degeneration, production of extracellular matrix catabolic factors, and expression of proinflammatory cytokines. Therefore, AdipoRon could be a new therapeutic candidate for alleviating the early stage of IVD degeneration.

The Identification of Risk Factors for Symptomatic Spinal Metastasis Onset: A Prospective Cohort Study of 128 Asymptomatic Spinal Metastasis Patients.

Background: Symptomatic spinal metastasis (SSM) decreases the activities of daily living (ADL) and quality of life of cancer patients. However, the risk factors for SSM onset remain unclear. This prospective cohort study aimed to statistically analyze the significant risk factors. Methods: From 2016 to 2018, 210 consecutive patients with spinal metastases were prospectively registered. Patients with SSM at the first consultation and those who were unable to be followed-up owing to poor general condition were excluded. The demographic factors (age, sex, primary cancer, performance status, and ADL), clinical factors (radiation therapy, chemotherapy, molecularly targeted drugs, and bone-modifying agents (BMAs)), and Spinal Neoplastic Instability Score (SINS) were evaluated. Multivariate analysis was performed to identify the risk factors for SSM onset. Furthermore, the threshold was calculated from the receiver operating characteristic curve using the Youden index. Results: Thirty-nine patients who presented with SSM at the first consultation and 43 patients who were unable to be followed-up owing to poor general condition were excluded. Finally, 128 asymptomatic patients were included. Thirty-seven patients (28.9%) developed SSM during the follow-up period. The total SINS (OR: 1.739; 95% CI: 1.345-2.250) was identified as the most significant factor. The cut-off value of the SINS was 9.5 (sensitivity: 67.6%; specificity: 83.5%). Twenty-five (62.5%) of the forty patients with a SINS ≥ 10 developed SSM within a mean of 5.5 months (95% CI: 1.17-9.83). Furthermore, all patients with a SINS ≥ 13 developed SSM (n = 5) within a mean of 1.37 months (95% CI: 0.0-3.01). Conclusions: This study identified the significant risk factors for SSM onset and the threshold of the SINS. If long-term survival is expected, patients with a SINS ≥ 10 should be considered for intervention to prevent SSM.

Survival Rate after Palliative Surgery Alone for Symptomatic Spinal Metastases: A Prospective Cohort Study.

The effect of spine surgery for symptomatic spinal metastases (SSM) on patient prognosis remains unclear. This study aimed to reveal the prognosis of patients with SSM after spine surgery. One hundred twenty-two patients with SSM were enrolled in this prospective cohort study. The patients who received chemotherapy after enrollment were excluded. The decision of surgery depended on patient's willingness; the final cohort comprised 31 and 24 patients in the surgery and non-surgery groups, respectively. The patients were evaluated by their performance status (PS), activities of daily living (ADL) and ambulatory status. Survival was evaluated by the Kaplan-Meier method. The PS, ADL and ambulation were significantly improved in the surgery group compared to non-surgery group. The median survival was significantly longer in the surgery group (5.17 months, 95% confidence interval (CI) 3.27 to 7.07) than in the non-surgery group (2.23 months, 95% CI 2.03 to 2.43; p = 0.003). Furthermore, the patients with a better PS, ADL and ambulatory status had a significantly longer survival. Surgery improved the PS, ADL, ambulation and survival of patients with SSM. In the management of SSM, spine surgery is not only palliative but may also prolong survival.

Influence of the Preoperative Duration of Symptoms on Patients' Clinical Outcomes after Minimally Invasive Surgery-Transforaminal Lumbar Interbody Fusion for Degenerative Lumbar Spinal Diseases.

Background and Objectives: The impact of the duration of symptoms (DOS) on postoperative clinical outcomes of patients with degenerative lumbar spinal diseases is important for determining the optimal timing of surgical intervention; however, the timing remains controversial. This prospective case−control study aimed to investigate the influence of the preoperative DOS on surgical outcomes in minimally invasive surgery-transforaminal lumbar interbody fusion (MIS-TLIF). Materials and Methods: Patients who underwent single-level TLIF for lumbar degenerative diseases between 2017 and 2018 were reviewed. Only patients with full clinical data during the 1-year follow-up period were included. The patients were divided into two groups (DOS < 12 months, group S; DOS ≥ 12 months, group L). The clinical outcomes, including the Oswestry disability index (ODI) and visual analog scale (VAS) for lower back pain, leg pain, and numbness, were investigated preoperatively and at 1, 3, and 6 months, as well as 1 year, after surgery. Furthermore, postoperative patient satisfaction 1 year after surgery was also surveyed. Results: A total of 163 patients were assessed: 60 in group S and 103 in group L. No differences in baseline characteristics and clinical outcomes were found. The ODI and VAS significantly improved from the baseline to each follow-up period (all p < 0.01). Group S had significantly lower ODI scores at 3 months (p = 0.019) and 6 months (p = 0.022). In addition, group S had significantly lower VAS scores for leg pain at 3 months (p = 0.027). In a comparison between both groups, only the patients with cauda equina symptoms showed that ODI and leg pain VAS scores at 3 months after surgery were significantly lower in group S (19.9 ± 9.1 vs. 14.1 ± 12.5; p = 0.037, 7.4 ± 13.9 vs. 14.7 ± 23.1; p = 0.032, respectively). However, the clinical outcomes were not significantly different between both groups 1 year after surgery. Patient satisfaction was also not significantly different between both groups. Conclusions: Patients with a shorter DOS tended to have a significantly slower recovery; however, clinical outcomes 1 year after surgery were good, regardless of the DOS.

Medial Pelvic Migration of the Lag Screw after Intramedullary Nailing for Trochanteric Femoral Fracture.

Internal fixation with intramedullary nails has gained popularity for the treatment of trochanteric femoral fractures, which are common injuries in older individuals. The most common complications are lag screws cut-out from the femoral head and femoral fracture at the distal tip of the nail. Herein, we report a rare complication of postoperative medial pelvic migration of the lag screw with no trauma. The patient was subsequently treated by lag screw removal via laparoscopy. This case suggests that optimal fracture reduction, adequate position of the lag screw, and careful attention to set screw insertion are important to prevent complications. Additionally, laparoscopic surgery might be able to remove the lag screw more safely than removal from the femoral side.

Spinal Subarachnoid Hematoma After Cerebrospinal Fluid Drainage in Thoracoabdominal Aortic Aneurysm Repair: Case Report and Literature Review.

BACKGROUND: Cerebrospinal fluid (CSF) drainage reduces the risk of paraplegia in thoracoabdominal aortic aneurysm (TAAA) repair. Intracranial hemorrhage after TAAA repair has been reported as a rare complication of CSF drainage; however, spinal subarachnoid hematoma has never been reported. Here, we present a case of lumbosacral subarachnoid hematoma after CSF drainage in TAAA repair. CASE DESCRIPTION: The patient was a 76-year-old man who was hospitalized for TAAA repair. Just before the operation, a CSF drainage catheter was inserted into the L4/5 vertebral interspace. Continuous CSF drainage was performed during the operation. The CSF drain was clamped just after the operation, and the drainage catheters were removed at 24 hours after the operation. On postoperative day 1, the patient experienced pain and paralysis in both lower limbs that worsened over time. Magnetic resonance imaging of the brain and spinal cord was indicative of a spinal subarachnoid hematoma. Removal of hematoma with thoracolumbar and lumbosacral laminectomy was performed, and immediately after the surgery, the pain and paralysis in both lower limbs improved. Six months after the removal of the hematoma, the paralysis in both lower limbs completely resolved and the patient achieved the preinjury activity level. CONCLUSIONS: We present a rare case of lumbosacral subarachnoid hematoma after CSF drainage in TAAA repair. We should consider spinal subarachnoid hematoma when paralysis in the lower limbs occurs after CSF drainage.