Utility of a Navigated High-Speed Drill in Robotic-Assisted Screw Placement for Spine Surgery

Purpose To elucidate the utility of a navigated high-speed drill used after the version upgrade in surgeries assisted by a spinal robotics system. Methods The subjects were 166 patients who underwent screw placement using a spinal robotics system between April 2021 to July 2023. A significant change during the study was the introduction of a navigated high-speed drill in 80 post-upgrade cases, aimed at improving drilling accuracy. Screw accuracy was analyzed using the Gertzbein and Robbins classification on postoperative CT scans. Screws placed before (pre-upgrade group: 718 screws in 86 cases) and after the system upgrade (post-upgrade group: 747 screws in 80 cases) were compared in terms of perfect accuracy and deviation rates. Results There were no significant differences in demographics or surgical details between the two groups. No significant differences were observed in the overall perfect accuracy rate and deviation rate (2.4% pre-upgrade vs. 2.0% post-upgrade) between the two groups. For the percutaneous pedicle screw (PPS), the perfect accuracy rate was significantly higher, and the deviation rate was significantly lower in the post-upgrade group (26.1% pre-upgrade vs. 4.4% post-upgrade). Notably, the post-upgrade group achieved 100% perfect accuracy and 0% deviation for the cortical bone trajectory screw (CBT) technique. Conclusions The introduction of the navigated high-speed drill did not significantly alter the overall perfect accuracy or deviation rates for robotic-assisted screw placement. However, its use did demonstrate improved outcomes in specific techniques such as PPS and CBT, indicating its potential value in addressing skiving in robotic-assisted minimally invasive surgeries.

Learning curves for robotic-assisted spine surgery: an analysis of the time taken for screw insertion, robot setting, registration, and fluoroscopy

PURPOSE

The purpose of this study was to clarify the learning curve for robotic-assisted spine surgery. We analyzed the workflow in robotic-assisted spine surgery and investigated how much experience is required to become proficient in robotic-assisted spine surgery.

METHODS

The data were obtained from consecutive 125 patients who underwent robotic-assisted screw placement soon after introducing a spine robotic system at a single center from April 2021 to January 2023. The 125 cases were divided into phases 1-5 of sequential groups of 25 cases each and compared for screw insertion time, robot setting time, registration time, and fluoroscopy time.

RESULTS

There were no significant differences in age, body mass index, intraoperative blood loss, number of fused segments, operation time, or operation time per segment between the 5 phases. There were significant differences in screw insertion time, robot setting time, registration time, and fluoroscopy time between the 5 phases. The screw insertion time, robot setting time, registration time, and fluoroscopy time in phase 1 were significantly longer than those in phases 2, 3, 4, and 5.

CONCLUSION

In an analysis of 125 cases after the introduction of the spine robotic system, the screw insertion time, robot setting time, registration time, and fluoroscopy time were significantly longer in the 25 cases in the period initially after introduction. The times were not significantly different in the subsequent 100 cases. Surgeons can be proficient in robotic-assisted spine surgery after their experience with 25 cases.

Long-term changes in bone mineral density following adolescent idiopathic scoliosis surgery: a minimum 34-year follow-up

PURPOSE

To investigate longitudinal changes in bone mineral density (BMD) in middle-aged female patients who underwent spinal fusion for adolescent idiopathic scoliosis (AIS).

METHODS

The study subjects were 229 female patients who were diagnosed with AIS and underwent spinal fusion between 1968 and 1988. A two-step survey study was conducted on 19 female AIS patients. BMD, Z-scores, T-scores, and the prevalence of osteoporosis and osteopenia were compared between the initial (2014-2016) and second (2022) surveys. Correlations between the annual changes in Z-scores and T-scores with radiographic parameters, body mass index (BMI), and the number of remaining mobile discs were analyzed.

RESULTS

BMD decreased significantly from the initial (0.802 ± 0.120 g/cm2) to the second survey (0.631 ± 0.101 g/cm2; p < 0.001). Z-scores decreased from 0.12 ± 1.09 to - 0.14 ± 1.04, while T-scores decreased significantly from - 0.70 ± 1.07 to - 1.77 ± 1.11 (p < 0.001). The prevalence of osteopenia and osteoporosis increased significantly from 36.8% to 89.5% (p = 0.002), but the increase in osteoporosis alone was not statistically significant (5.3% to 26.3%; p = 0.180). Moderate negative correlations were found between annual changes in Z-scores and both main thoracic (MT) curve (r = - 0.539; p = 0.017) and lumbar curve (r = - 0.410; p = 0.081). The annual change in T-scores showed a moderate negative correlation with the MT curve (r = - 0.411; p = 0.081).

CONCLUSION

Significant reductions in BMD and an increased prevalence of osteopenia and osteoporosis were observed in middle-aged female AIS patients who had undergone spinal fusion. The decline in Z-scores in patients with AIS suggested that there was an accelerated loss of BMD compared with the general population. Larger residual curves could pose an added osteoporosis risk. Further research is needed to understand if the onset of osteoporosis in AIS patients is attributable to the condition itself or the surgical intervention.

Comparison of Radiographic and Patient-Reported Outcomes After Surgery in Adolescent Idiopathic Scoliosis Between Robotics and Navigation: An Analysis Using Propensity Score Matching

Purpose This study aimed to compare the radiographic and patient-reported outcomes after surgery in adolescent idiopathic scoliosis (AIS) between robotics and navigation using propensity score matching. Methods This retrospective study involved 50 patients undergoing posterior spinal fusion for AIS between October 2016 and August 2022, utilizing navigation or robotic systems, analyzing them using propensity score matching. The evaluations included assessments using X-ray, Scoliosis Research Society 22-Item (SRS-22) Questionnaire, and CT, considering variables such as age, gender, BMI, and Lenke type. Results Post matching, 13 cases each from robotics and navigation groups were compared. No significant differences were found in the demographic variables, preoperative X-ray parameters, and preoperative SRS-22 scores between the two groups. The robotics group demonstrated a higher perfect accuracy rate (94.0% vs. 84.7%, p=0.005) and a lower deviation rate in pedicle screw placements (1.6% vs. 4.1%, p=0.223). At one year postoperatively, there were no significant differences in the X-ray parameters between both groups. Likewise, no significant differences were found in each domain of SRS-22, but function, self-image, mental health, and satisfaction scores were numerically higher in the robotics group. Conclusion The application of a spinal robotic system in AIS surgery presented enhanced screw accuracy and lower deviation rates, compared to navigation, with no significant differences observed in the X-ray parameters and each domain of SRS-22 at one year postoperatively. This suggests that, to improve patient quality of life (QOL), it is essential for robotic-assisted spine surgery to focus not only on screw accuracy but also on the development of novel robotic-assisted techniques.

Accuracy of robotic-assisted pedicle screw placement comparing junior surgeons with expert surgeons: Can junior surgeons place pedicle screws as accurately as expert surgeons?

BACKGROUND

The purpose of this study was to verify whether a spine robotic system was useful for junior surgeons.

METHODS

Twenty-seven patients underwent posterior spinal fusion with open surgery using a spine robotic system (Mazor X Stealth Edition, Medtronic Inc., Dublin, Ireland) from April to August 2021. Pedicle screw insertions were performed by five surgeons. The surgeon and insertion time were recorded for each pedicle screw. Two surgeons who are board-certified spine surgeons by the Japanese Society for Spine Surgery and Related Research (JSSR) were defined as the expert surgeon group. Three surgeons who were training to acquire qualifications as JSSR board certified spine surgeons were defined as the junior surgeon group. In postoperative CT images, the deviation of 255 pedicle screws was evaluated using the Gertzbein-Robbins (GR) grades.

RESULTS

In the expert surgeon group, the GR grades were Grade A for 79 screws (90.8%), Grade B for 6 (6.9%), Grade C for 2 (2.3%), and 0 (0%) for Grades D and E. I In the junior surgeon group, the GR grades were Grade A for 162 screws (96.4%), Grade B for 6 (3.6%), and 0 (0%) for Grades C, D, and E. There was no significant difference in the deviation rate between surgeon groups (p = 0.08). The mean insertion times were 174.5 ± 83.0 s in the expert surgeon group and 191.0 ± 111.0 s in the junior surgeon group. There was no significant difference in the insertion time between surgeon groups (p = 0.22).

CONCLUSIONS

There were no significant differences in the deviation rate and the insertion time of robotic-assisted pedicle screw placement between expert surgeons and junior surgeons who were training to acquire qualifications as JSSR board certified spine surgeons. Robotic-assisted pedicle screw placement can be effectively employed by junior surgeons.

Safety of robotic-assisted screw placement for spine surgery: Experience from the initial 125 cases

BACKGROUND

The present study aimed to evaluate the safety of robot-assisted screw placement in 125 cases after introducing a spinal robotics system and to identify the situations where deviation was likely to occur.

METHODS

The subjects were 125 consecutive patients who underwent robotic-assisted screw placement using a spinal robotics system (Mazor X Stealth Edition, Medtronic) from April 2021 to January 2023. The 1048 screws placed with robotic assistance were evaluated. We investigated intraoperative adverse events of the robotics system and complications occurring within 30 days after surgery. We evaluated screw accuracy and deviation and compared them for vertebral levels, screw insertion methods (open traditional pedicle screw [Open-PS], cortical bone trajectory screw [CBT], percutaneous pedicle screw [PPS], and S2 alar iliac screw [S2AIS]), diagnosis, and phases of surgical cases.

RESULTS

The deviation rate of robotic-assisted screw placement for spine surgery was 2.2%. Complications were reoperation due to implant-related neurological deficit in 0.8% and surgical site infection in 0.8%. There was significant difference in the deviation rate between vertebral levels. The deviation rate of the T1-T4 level was high at 10.0%. There was significant difference in the deviation rate between Open-PS, CBT, PPS, and S2AIS. The PPSs had a high deviation rate of 10.3%. The deviation rates were not significantly different between patients with and without deformity. The deviation rate did not change depending on the experience of surgical cases, and the deviation rate was favorable from the onset.

CONCLUSION

Although the robotic-assisted screw placement was safe, we should be extra vigilant when placing screws in the upper thoracic region (deviation rate 10.0%) and when using PPSs (deviation rate 10.3%).

Nutritional Status Is Associated With Survival Following Spinal Surgery in Patients With Metastatic Spinal Tumors

Background Preoperative and postoperative nutritional statuses are reported to influence the outcomes and complications of multidisciplinary treatment, including patient survival. However, a causal relationship between nutritional status and survival following spinal surgery has not been demonstrated in patients with metastatic spinal tumors. The present study was, therefore, designed to evaluate the correlation between the nutritional status and survival following spinal surgery in patients with metastatic spinal tumors. Methods Nutritional status was evaluated using the Japanese version of the modified Glasgow prognostic score (JmGPS), C-reactive protein-to-albumin ratio (CAR), prognostic nutrition index (PNI), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR), which were calculated from the results of preoperative laboratory tests. The survival period was defined as the interval between the day preoperative data were obtained and the day of death. Results Data from 57 of 113 consecutive surgeries were retrieved. The CAR, JmGPS, and PNI were significantly correlated with the survival period (CAR, r = -0.576, P < 0.01; JmGPS, r = -0.537, P < 0.01; PNI, r = 0.316, P = 0.02). Furthermore, patients with 0 points on the JmGPS had significantly longer survival. Using receiver operating characteristic curves, CAR cutoffs of ≥0.880 and ≤0.220 were found to be optimal in predicting the 90- and 180-day postoperative survival, respectively. Conclusions The findings of the present study indicate that preoperative assessment of the JmGPS, CAR, and PNI has utility in estimating nutritional status and predicting survival following spinal surgery in patients with metastatic spinal tumors.

Health-Related Quality of Life of Patients With Adolescent Idiopathic Scoliosis at Least 40 Years After Surgery

STUDY DESIGN

Retrospective study.

OBJECTIVE

The aim was to clarify the health-related quality of life (QOL) of patients who had adolescent idiopathic scoliosis (AIS) at a minimum of 40 years after surgery.

SUMMARY OF BACKGROUND DATA

The postoperative health-related QOL of middle-aged patients with AIS has been reported to be good, but that of middle-aged and older patients with AIS has yet to be completely explored.

MATERIALS AND METHODS

We included 179 patients with AIS who underwent spinal fusion(s) between 1968 and 1982. We conducted three surveys in 2009, 2014, and 2022. Patients self-administered both the Scoliosis Research Society-22 and the Roland-Morris Disability questionnaires three times (in 2009, 2014, and 2022) and the Oswestry Disability Index (ODI) questionnaire was self-administered in 2014 and 2022. We considered patients who responded to all three surveys in 2009, 2014, and 2022.

RESULTS

For the Scoliosis Research Society-22 questionnaires, no significant differences were detected among the three time points (2009, 2014, and 2022) for total scores, function domain, pain domain, self-image domain, mental domain, or satisfaction domain. The results of the Roland-Morris Disability Questionnaire were also not significantly different among the surveys over time. The ODI questionnaires revealed a significant worsening of the 2022 results compared with the 2014 results. Eight patients (29.6%) who had an ODI deterioration of 10% or more had numerically fewer mobile lumbar disks than those with <10% deterioration of the ODI, although the difference did not reach statistical significance.

CONCLUSION

Among patients with AIS who underwent spinal fusion(s) between 1968 and 1982, we found health-related QOL to be maintained over the last 13 years. Relatively good QOL was appreciated in this population of patients who are now middle-aged and older.

Accuracy of computer-assisted pedicle screw placement for adolescent idiopathic scoliosis: a comparison between robotics and navigation

PURPOSE

To compare the accuracy of pedicle screw placement in adolescent idiopathic scoliosis (AIS) between robotics and navigation and clarify the factors that cause screw deviation when robotics is used.

METHODS

Fifty consecutive patients who underwent posterior spinal fusions with computer-assisted pedicle screw placement including robotics and navigation for AIS were included. A total of 741 pedicle screws (250: Robot group, 491: Navi group) were evaluated on postoperative CT images. A rate of penetration of ≥ 2 mm was calculated as the deviation rate. After propensity score matching, we examined vertebral levels, the distance from the reference frame (RF), and the pedicle channel grade as factors for deviation.

RESULTS

The deviation rate was significantly lower in the Robot group than in the Navi group (Robot group: 1.6%, Navi group: 7.5%). After propensity score matching, 22 cases were extracted. At T5-T8, the deviation rate of the Robot group was significantly lower than that of the Navi group. In the Robot group, the T2-T4 deviation rate was significantly higher than at the other vertebral levels. The distance from the RF didn't affect the deviation rate. The deviation rate of pedicle channel Grade 4 (inner diameter of less than 1 mm) was significantly higher than for the other grades.

CONCLUSION

The deviation rate of robotics was 1.6%, lower than that of navigation. The narrow pedicles with an inner diameter of less than 1 mm (deviation rate: 22.2%) and the upper thoracic level (deviation rate: 14.3%) were factors related to screw deviation even when using robotics.

Impact of the COVID-19 Pandemic on Middle-Aged and Older Patients With Adolescent Idiopathic Scoliosis Who Underwent Spinal Fusion: A Questionnaire-Based Survey

Purpose To investigate the impact of the COVID-19 pandemic on middle-aged and older patients with adolescent idiopathic scoliosis (AIS) who underwent spinal fusion. Methods The subjects were 252 AIS patients who underwent spinal fusion between 1968 and 1988. The surveys were performed before the COVID-19 pandemic (a primary survey in 2014) and during the pandemic (a secondary survey in 2022). The self-administered questionnaires were mailed to the patients. We analyzed 35 patients (33 females and two males) who replied to both surveys. Results The pandemic had low impacts on 11 patients (31.4%). Two patients reported refraining from seeing a doctor because they were concerned about going to the clinic or hospital, eight reported that the pandemic impacted their work, and five reported fewer opportunities to go out (based on multiple-choice answers). Twenty-four patients reported that their lives were unaffected by the pandemic. No significant differences were detected between both surveys for Scoliosis Research Society-22 (SRS-22) in any domains (function, pain, self-image, mental, or satisfaction). The Oswestry Disability Index (ODI) questionnaires revealed a significant worsening of the survey during the pandemic compared with the survey before the pandemic. There was no significant difference in the impact of the pandemic between the ODI deterioration group (27.8%) and the ODI stable group (35.3%). Conclusion The COVID-19 pandemic had a low impact on 31.4% of middle-aged and older patients with AIS who underwent spinal fusion. The impact of the pandemic did not significantly differ between the groups with ODI deteriorations and the groups with stable ODI. The pandemic had a smaller impact on AIS patients at a minimum of 33 years after surgery.

Accuracy and Screw Insertion Time of Robotic-Assisted Cortical Bone Trajectory Screw Placement for Posterior Lumbar Interbody Fusion: A Comparison of Early, Middle, and Late Phases

Introduction The purpose of this study was to evaluate robotic-assisted cortical bone trajectory (CBT) screw placement. Early, middle, and late phases of robotic-assisted CBT screw placement were compared for accuracy and screw insertion time by comparing time and accuracy in every phase.  Methods A retrospective review was conducted on the initial 40 patients who underwent spinal fusion using CBT screws in one institution from September 2021 to September 2022 utilizing a spine surgery robot system (Mazor X Stealth Edition, Medtronic Inc., Dublin, Ireland). The inclusion criterion was one- or two-level posterior lumbar interbody fusion (PLIF). Exclusion criteria were 1) patients who underwent posterior-lateral fusion in other segments, 2) patients who underwent additional decompression in other segments, 3) patients who underwent reoperation, and 4) patients with spondylolysis. The deviation of the CBT screw was evaluated on computed tomography (CT) one week after surgery using the Gertzbein-Robbins grade system. The rate of Grade A was considered the perfect accuracy rate, and the rate of penetration of 2 mm or more (Grades C, D, and E) was calculated as the deviation rate. To assess the learning curve, patients were divided into three groups. The first 10 cases were in the early phase group, the subsequent 10 cases were in the middle phase group, and the last 10 cases were in the late phase group. We compared the perfect accuracy rate, deviation rate, operative time, operative time per segment, intraoperative blood loss, registration time, and screw insertion time among the three groups. Results Thirty patients met the criteria. Overall, the perfect accuracy (Grade A) rate of the screw was 95.3% and the deviation rate was 1.4%. The perfect accuracy rate was 90.4% in the early phase, 95.5% in the middle phase, and 100% in the late phase. The deviation rate was 3.8% in the early phase, 0% in the middle phase, and 0% in the late phase, and there was no statistically significant difference between the three groups. Among the three groups, the operative time, the operative time per segment, the intraoperative blood loss, and the registration time were not significantly different. There was no significant difference in the screw insertion time among the three groups, but it decreased with experience (early phase: 156.9 ± 54.7 sec, middle phase: 139.9 ± 41.6 sec, and late phase: 106.4 ± 39.9 sec, p=0.060). The screw insertion time of the late phase tended to be shorter than that of the early phase (p=0.052). Conclusions The deviation rate of robotic-assisted CBT screw placement with one- or two-level PLIF was 1.4%, which was highly accurate. The deviation rate was 3.8% in the early phase, 0% in the middle phase, and 0% in the late phase. Although the deviation rate was low even in the early period, the screw insertion time in the early 10 cases tended to be longer than that in the late 10 cases. After passing the experience of 10 cases, this study concluded that robotic-assisted CBT screw placement was proficient.

Robotics is useful for less-experienced surgeons in spinal deformity surgery

PURPOSE

To verify whether robotics was useful for surgeons who had less experience with spinal deformity surgery.

METHODS

A retrospective review was conducted of 70 consecutive patients who underwent robotic-assisted pedicle screw placements with open procedures using a spine robotic system (Mazor X Stealth Edition) at a single institution from April 2021 to April 2022. Gertzbein-Robbins grades were used to assess the deviation of the 599 pedicle screws in the postoperative CT images. The rate of Grade A was considered the perfect accuracy rate, and the rate of Grades C, D, and E was calculated as the deviation rate. The perfect accuracy rate and deviation rate were compared between the spinal deformity and the non-deformity groups. The perfect accuracy rate, deviation rate, and screw insertion time were compared in the spinal deformity cases between the expert surgeon group and the less-experienced surgeon group.

RESULTS

The deviation rate of the spinal deformity group was higher than that of the non-deformity group even though there was no statistically significant difference (spinal deformity group: 2.3%, non-deformity group: 1.2%, p = 0.350). In the spinal deformity cases, there was no significant difference in the perfect accuracy rate between the expert surgeon group and the less-experienced surgeon group, but the deviation rate was significantly lower in the less-experienced surgeon group (expert surgeon group: 5.0%, less-experienced surgeon group: 0%, p = 0.008). The screw insertion time was significantly shorter in the less-experienced surgeon group.

CONCLUSION

Robotics is particularly useful for surgeons with less experience in spinal deformity surgery.

The Learning Curve of Robotic-Assisted Pedicle Screw Placements Using the Cumulative Sum Analysis: A Study of the First 50 Cases at a Single Center

Introduction

The purpose of this study was to clarify how many cases surgeons need to experience to pass the learning phase of robotic-assisted spine surgery using the cumulative sum (CUSUM) analysis.

Methods

A retrospective review was conducted on the initial 50 consecutive patients who underwent robotic-assisted pedicle screw placements with open procedures using a spine robotic system (Mazor X Stealth Edition) at a single center from April 2021 to January 2022. There were 19 male and 31 female patients with a mean age of 58.7 (range, 13-86) years. To split the surgeries into the early and late phases using the CUSUM analysis of screw insertion time, we compared the screw insertion time, the robot setting time, the registration time, and the operation time in the early and late phases.

Results

The screw insertion time, the robot setting time, and the registration time declined as the number of surgical cases increased. The operation time did not decline as the number of surgical cases increased. The learning curve for screw insertion time can be separated into two stages based on the CUSUM analysis. The first 23 cases were in the early phase, and the later 27 cases were in the late phase. The mean screw insertion time was reduced from 3.2 min in the first 23 cases to 2.7 min in the subsequent 27 cases. The robot setting time and registration time in the late phase were also significantly shorter than those in the early phase.

Conclusions

The screw insertion time, robot setting time, and registration time decreased with experience. After 23 cases, surgeons passed the learning phase of robotic-assisted spine surgery and became more proficient.

Screw Insertion Time, Fluoroscopy Time, and Operation Time for Robotic-Assisted Lumbar Pedicle Screw Placement Compared With Freehand Technique

Introduction

The purpose of this study was to clarify the superiority of robotic-assisted lumbar pedicle screw placement in terms of screw insertion time, fluoroscopy time, and operation time.

Methods

The subjects were 46 patients who underwent a posterior lumbar interbody fusion with an open procedure for lumbar degenerative disease from April 2021 to February 2022. The robot group contained 29 cases of screw insertion using a spine robotic system (Mazor X Stealth Edition, Medtronic Inc., Dublin, Ireland). The freehand group contained 17 cases of screw insertion with the freehand technique utilizing the conventional C-arm image guidance. The screw insertion time, fluoroscopy time, and operation time were compared between the robot and the freehand group.

Results

The screw insertion time did not differ significantly between the two groups (robot group: 179.0 ± 65.2 sec; freehand group: 164.2 ± 83.4 sec; p = 0.507). The fluoroscopy time was significantly shorter in the robot group (robot group: 28.3 ± 25.8 sec; freehand group: 67.5 ± 72.8 sec; p = 0.011). The fluoroscopy time per segment was also significantly shorter in the robot group (robot group: 17.8 ± 23.0 sec; freehand group: 60.2 ± 74.8 sec; p = 0.007). The operation time was significantly longer in the robot group (robot group: 249.6 ± 72.5 min; freehand group: 195.8 ± 60.1 sec; p = 0.013), but the operation time per segment did not differ significantly between the two groups (robot group: 144.1 ± 39.0 min; freehand group: 159.7 ± 34.4 min; p = 0.477).

Conclusions

The screw insertion time and operation time per segment were similar when employing the spine robotic system compared to the freehand technique; however, the fluoroscopy time was shorter. The fluoroscopy time per segment in the robot group was 29.6% of the time of the freehand group using the C-arm. The surgeon's radiation exposure is thought to be decreased since the spine robotic system shortens the fluoroscopy time.

Diagnosis of Spinal Infection with Alpha-defensin Lateral Flow Test: A Preliminary Report

Introduction

The alpha-defensin lateral flow test has been used in periprosthetic joint infection as a diagnostic support tool because of its simplicity and speed. However, the test has not been used to diagnose spinal infections. The purpose of this study was to investigate the efficacy of the alpha-defensin lateral flow test for diagnosing spinal infections.

Methods

The subjects were 11 patients who were suspected of having spinal infections from October 2019 to August 2021 and underwent biopsies at a single institution. There were nine male and two female patients, with an average age of 60.7 (14-87) years. For diagnosing infection, the patient's consent for biopsy was obtained, and the sample was collected by computed tomography-guided aspiration biopsy or open biopsy at the site considered to be a possible abscess. The samples were subjected to a bacterial culture test, an acid-fast bacillus culture test, and an alpha-defensin lateral flow test (Synovasure^Ⓡ lateral flow test; Zimmer Biomet, IN, USA).

Results

Of the 11 suspected spinal infections, the alpha-defensin lateral flow test was positive in 8 cases, negative in 2 cases, and undeterminable in 1 case. Of the 10 cases excluding the undeterminable case, the definitive diagnosis was 9 cases of spinal infection (spondylitis: 6 cases, spinal implant infection: 3 cases) and 1 case of vertebral body fracture. The alpha-defensin lateral flow test demonstrated a sensitivity of 88.9%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 50%. The biopsy sample culture test demonstrated a sensitivity of 77.8%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 33.3%.

Conclusions

We suggested that the alpha-defensin lateral flow test might be useful as a diagnostic support tool for spinal infections.

Increase in pancreatic enzymes following spinal alignment changes in the thoracolumbar junction: Potential for acute pancreatitis after kyphosis correction

BACKGROUND

Despite the identification of various risk factors for pancreatitis and hyperamylasemia following spinal surgery, no report has investigated the relationship between spinal alignment changes and elevated serum amylase levels. The purpose of this study was to investigate the relationship between spinal alignment changes and hyperamylasemia after spinal fusion.

METHODS

A total of 222 patients whose serum pancreatic amylase levels were measured before and after spinal surgery from December 2017 to May 2019 were included. Inclusion criteria were (1) spinal fusion including the thoracolumbar junction (T10-L2) and (2) serum pancreatic amylase measurements before, immediately after surgery (day 0), the day after surgery (day 1), and 1 week after surgery. Ultimately, 37 patients who met the criteria were analyzed. Patients with hyperamylasemia at day 0 and/or day 1 (H group) were then compared with those without hyperamylasemia (N group).

RESULTS

No significant differences in age, sex, surgical procedure, number of fused segments, intraoperative blood loss, operative time or American Society of Anesthesiologists physical status classification were observed between both groups. The H group had significantly larger preoperative thoracolumbar kyphosis (TLK) (H group: 22.6°, N group: 6.4°), postoperative TLK (H group: 16.8°, N group: 7.6°), and preoperative T12-L1 kyphosis angles (H group: 16.2°, N group: 7.9°) compared with the N group. Moreover, the H group demonstrated a significant decrease in TLK after surgery (H group: -5.8°, N group: 1.6°).

CONCLUSIONS

Risk factors for hyperamylasemia included a large preoperative TLK angle and a greater postoperative decrease in TLK. Thus, decreased TLK after spinal fusion surgery should prompt careful attention to abdominal symptoms and elevated pancreatic amylase levels.

Tranexamic Acid Reduces Total Blood Loss and the Amount of Stored Preoperative Autologous Blood Donation Needed for Adolescent Idiopathic Scoliosis Patients Undergoing Posterior Spinal Fusion

Introduction

There are few published studies on posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) that have reported that the stored amounts of autologous blood donation (ABD) needed for the procedure were estimated by taking into account total blood loss (TBL). The aim of this study was to clarify the following clinical questions: (1) Does the use of tranexamic acid (TXA) reduce the TBL during PSF for AIS? (2) What volume of ABD should be stored to avoid allogeneic blood transfusions?

Methods

This study investigated 44 female patients who underwent PSF for AIS. A total of 33 patients underwent PSF without TXA (non-TXA group) and 11 patients underwent PSF with TXA (TXA group). TBL was determined by the hemoglobin (Hb) balance method calculated with circulating blood volume, Hb levels, hematocrit (Ht) levels before and three days after surgery, and the volumes of blood transfusions, including stored ABD. For the TXA patients, TBL was used to determine the appropriate amount of stored ABD and the number of ABD collections.

Results

The amount of TBL was lower in the TXA group compared to the non-TXA group. The mean required volume of stored ABD in the TXA group was 218.2 ± 577.3 mL, with a required maximum volume of 699.0 mL. The proportions of patients requiring allogeneic blood transfusion were as follows: 72.7% for those with no ABD collection, 45.5% for one ABD collection, and 0% for two ABD collections when TXA was used during surgery. 

Conclusions

TXA reduced the TBL of patients undergoing PSF for AIS. The maximum amount of stored ABD needed was 699.0 mL. Allogeneic blood transfusion can be avoided by storing two ABD collections when TXA is used during the surgery.

Mobile Application for Scoliosis Screening Using a Standard 2D Digital Camera

Several scoliosis detection systems, using three-dimensional (3D) cameras or sensors, have been developed in recent years. Because these systems require specific 3D digital cameras or sensors, and the equipment is expensive, they are rarely used in many countries and regions. The development of a scoliosis screening system that uses standard two-dimensional (2D) digital cameras that come with tablet personal computers (PCs) and smartphones will facilitate the efforts made to detect scoliosis patients on a global scale. The aim of this technical note was to report on a mobile application for scoliosis screening that uses a standard 2D digital camera. The subjects were patients aged 10 years or older who visited our outpatient clinic for scoliosis or suspected scoliosis and underwent whole-spine radiography. Photographs of subjects were obtained using a standard 2D digital camera connected to a tablet PC. For analysis, we used the simplified scoliosis diagnosis support application (Cobb First, Its Corporation, Kawasaki, Japan) which operates on Windows 10 operating system (OS). When an image was imported into the application, it was displayed within a grid. The grid consisted of four columns and 40 rows and was divided into 160 areas. Each image was converted into binarized image data by demarcating skin and background color. The image of the subject was displayed as a black subject on a white background. Two types of conditions were presented to process differences in the environment versus skin color. A binarized image with a clear outline was selected. The determination was displayed as a percentage of the black area in each grid. In each row of the grid, the left and right sides of the black area were compared, and the part with the larger area with respect to the opposite side was colored and displayed. Depending on the ratio of the difference, it was possible to display green, yellow, and red. If this mobile application is available for clinical use, it has the potential to improve the accuracy of screening by physicians and nurses. Furthermore, it may also be used globally to check for possible evidence of scoliosis at home to facilitate the early detection of patients who require a medical checkup for scoliosis. Although it is essential to perform a radiographic examination for the definitive diagnosis of scoliosis, our future goal is to limit radiation exposure and replace a radiologic method with one based on a tablet PC or smartphone. A mobile application using a standard 2D digital camera may improve the accuracy of screening scoliosis by physicians and may have global application in home environments.

Pulmonary Function Improves in Patients with Adolescent Idiopathic Scoliosis who Undergo Posterior Spinal Fusion Regardless of Thoracoplasty: A Mid-Term Follow-Up

Introduction

The purpose of the present study was to determine, in a mid-term follow-up 5 years or more after surgery, the forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and expiratory flow in patients with adolescent idiopathic scoliosis (AIS) who underwent posterior spinal fusion (PSF) with or without thoracoplasty.

Methods

The subjects were 134 patients with AIS who underwent PSF between 2004 and 2013. Forty-five patients agreed to participate in the study. We divided the patients into two groups as follows: 24 patients who underwent PSF with thoracoplasty from 2004 to 2010 in the TP group and 21 patients who underwent PSF without thoracoplasty from 2011 to 2013 in the non-TP group. We evaluated whole spine X-ray imaging and pulmonary function tests (PFTs) in these patients. PFTs measured FVC, FEV1, peak expiratory flow (PEF), maximum expiratory flow at 50% FVC (V50), maximum expiratory flow at 25% FVC (V25), and the ratio of V50 to V25 (V50/V25).

Results

The main thoracic curves were 53.6 ± 10.1° before surgery, 19.8 ± 7.6° 1 week after surgery, 22.3 ± 8.3° 2 years after surgery, and 23.3 ± 7.6° at the most recent observation. Compared with preoperative values, FVC, FEV1, and % FEV1 were improved significantly at the most recent observation. No significant difference was observed between % FVC before surgery and at the most recent observation. Compared with preoperative values, PEF, V50, and V25 were improved significantly at the most recent observation. V50/V25 did not change significantly. The changes in PFT values in the TP group and the non-TP group were compared. No significant differences were observed in FVC, % FVC, FEV1, % FEV1, PEF, V50, or V25.

Conclusions

Regardless of whether thoracoplasty was performed or not, FVC, FEV1, and expiratory flow were improved 5 years or later after PSF.

Optimization of the Revised Tokuhashi Scoring System: New Prognostic Criteria for Metastatic Spinal Tumor in Surgical Cases

Introduction

The revised Tokuhashi scoring system has been used to predict survival in patients with metastatic spinal tumors. Because of the rapid progress of cancer therapy, the original criteria of the revised Tokuhashi scoring system became in recent years unsuitable. The study aim was to evaluate the validity of the revised Tokuhashi scoring system in patients who underwent spinal surgery and to establish new prognostic criteria.

Methods

The study enrolled 85 patients with metastatic spinal tumors who underwent spinal surgery. The patients' survival outcomes in October 2019 were as follows: 57 patients died; 10 were alive; and 18 had unknown prognoses. The study evaluated the validity of the Tokuhashi scoring system, and established and validated the new prognostic criteria.

Results

The accuracies of the Tokuhashi scoring system were 66.7% in the short-term group, 60% in the midterm group, and 100% in the long-term group. Among the patients who died, the survival period and total score were significantly correlated. Total score cutoff point was six points in the patients whose predicted survival was <6 months. Total score cutoff point was eight points in the patients whose predicted survival was ≥1 year.

Conclusions

As the prognosis of patients has improved in recent years, the original criteria of the revised Tokuhashi scoring system have been questioned as to their suitability to current treatments. Especially, the survival period among the patients with total scores of 7 and 8 points was not accurate. According to this study, the new prognostic criteria of the revised Tokuhashi scoring system were set to 0 to 6 points for the short-term group, 7 points for the midterm group, and 8 to 15 points for the long-term group.

540 Assessment of left ventricular ejection fraction from echocardiographic images using machine learning algorithm

Background

Precise and reliable echocardiographic assessment of LVEF is needed for clinical decision-making. LVEF is currently determined through an observer dependent process that requires manual tracing. To remove this manual tracing step, which is both time-consuming and user dependent, automatic computer aided diagnosis systems may be useful in the clinical setting.

Purpose

The aim of this study was to evaluate whether a 3-dimensional convolutional neural networks (3DCNN) could estimate left ventricular ejection fraction (LVEF) and differentiate types of heart failure (preserved EF/reduced EF) using conventional 2-dimensional echocardiographic images.

Methods

We developed a deep learning model to automatically estimate LVEF from echocardiographic data. The 3DCNN model was trained on a dataset of 340 patients. The dataset creation consisted of three main steps: firstly, for each exam, cine-loops showing the parasternal and apical views were manually selected; then, 10 sequential frames were extracted from each 1 beat and; finally, each frame was pre-processed to fit the learning model. Each patient has 2 views, resulting in a total of 6,800 images. Reference LVEF measurement was calculated by two highly experienced readers in each case.

Results

A good correlation was found between estimated LVEF based on apical 2 and 4 chamber views and reference LVEF (r =0.88, p &lt;0.001) (Figure). For classification of heart failure types based on LVEF (LVEF ≥50% or &lt;50%), the area under the receiver-operating characteristic curve by the 3DCNN algorithm was over 0.95.

Conclusions

The 3DCNN can be applied to estimate and classify the LVEF in the clinical setting. Furthermore, this work will serve as a driver for future research using million image databases.

Abstract 540 Figure.

P1526 Updated prevalence of lambls excrescences using the latest three-dimensional transesophageal echocardiography

Background

Lambl’s excrescences (LEs), filiform strands that occur at sites of cardiac valves, have been suggested the cause cryptogenic stroke. The diagnosis is primarily based upon the echocardiographic study, but conventional two-dimensional transthoracic echocardiography has limitation to detect such as small strands. Latest three dimensional-transesophageal echocardiography (3D-TEE) have high-resolution images with many slices, so small structures are able to be clearly visible and detected.

Purpose

The aim of this study was to assess the prevalence of LEs using the latest 3D-TEE images.

Methods

We retrospectively reviewed consecutive 140 patients who underwent 3D-TEE from November 2018 to May 2019. Forty-seven patients were excluded due to unmeasurable, such as mitral valve prolapse, severe aortic stenosis, prosthetic valves and poor-quality images. We carefully evaluated the mitral and aortic valve leaflets in order to find mobile string structure (diameter &lt;1 mm and length 1–20 mm) in each cardiac cycle. Total analyzed images were over 50 slices per one patient.

Results

Among 93 patients, 83 patients (89%) was detected the presence of LEs. No difference in age and gender were found between patients with LEs and patients without LEs. Of the total 83 patients, there were 35 patients with strands on mitral valve, 32 patients with strands on aortic valve, and 16 patients with strands on both valves. Distribution of LEs at each valve leaflet were shown in Figure. Right coronary cusp of aortic valve (42%) and P2 of mitral valve (35%) were high prevalence among leaflets.

Conclusions

3D-TEE provides an update prevalence of LEs. The prevalence of LEs might be potentially high in the real world.

Abstract P1526 Figure.

MRI evaluation of dural sac enlargement by interspinous process spacers in patients with lumbar spinal stenosis: Does it play a role in the long term?

BACKGROUND

To investigate dural sac enlargements and spinal alignments in patients who underwent indirect decompression with interspinous spacers.

METHODS

The subjects were 20 patients who underwent indirect decompression using an interspinous spacer (X-STOP) without laminectomy. Of these 20 patients, 1 patient underwent implant removal surgery 1 month after X-STOP surgery and two patients dropped out. Ultimately, 17 patients were included in this study. MRI and X-ray images were investigated before surgery, 1 week after surgery, 3 months after surgery, and 2 years after surgery.

RESULTS

On MRI, the mean cross-sectional areas of the dural sac were 52.7 mm² before surgery, 73.2 mm² 1 week after surgery, 62.4 mm² 3 months after surgery, and 58.3 mm² 2 years after surgery. There was a significant 37% increase at 1 week postoperatively compared with that before surgery, but there were no significant differences between 3 months postoperatively and 2 years postoperatively. The disc angle in an extension posture was significantly decreased at 1 week after surgery compared with that before surgery, but there were no significant differences between before surgery, 3 months after surgery, and 2 years after surgery.

CONCLUSIONS

The interspinous process spacer increased the dural sac area by 37% 1 week after surgery, but the enlargement was not maintained at 3 months or 2 years after surgery. The use of interspinous process spacers produced an enlargement of the dural sac by limiting extension of the stenotic level only. However, its effect diminished 2 years after surgery.

P3437Impact of epicardial adipose tissue on global longitudinal strain: a study in patients with normal left ventricular ejection fraction

Background

Epicardial adipose tissue (EAT) locates anatomically and functionally contiguous to the myocardium and coronary arteries. It has been suggested that EAT accumulation is associated with cardiac remodeling and impaired cardiac performance. However, its role in left ventricular (LV) wall strain remains unclear.

Purpose

In this study, we aimed to clarify: whether EAT accumulation is related to global longitudinal (GLS), circumferential (CS) and radial strain (RS); and if so, in which extent or by which amount of EAT are required to deteriorate these strain.

Methods

Total 180 patients who had no obstructive coronary artery disease (CAD) on multi-detector computed tomography (MDCT) coronary angiography and normal left ventricular ejection fraction (LVEF) on conventional echocardiography were recruited. Cardiac CT was used to quantify EAT volume (EATV) and echocardiographic speckle tracking was used to measure the GLS, CS and RS. EATV index (EATV/Body surface area) was determined as: EAT volume, the sum of the EAT area from the base to the apex of the heart (cm3)/body surface area (m2). Adipose tissue was determined as the density range between −190 and −30 Hounsfield unit. According to the median value (68 cm3/m2), patients were divided into lower and higher EATV index two groups.

Results

In higher EATV index group (95±19 cm3/m2), mean age, body mass index (BMI), prevalence of hyperlipidemia and prevalence of CAD were larger than in lower EATV index group (48±14 cm3/m2). Male gender, hypertension, diabetes, smoking and LV mass index were comparable between two groups. Patients in higher EATV index had lower GLS than those in lower EATV index (−19.4±1.2% vs. −18.8±1.3%, p=0.002). However, there were no significant difference between two groups regarding to the CS and RS. Linear regression analysis showed that there was strong correlation between EATV index and GLS (R=0.216, p=0.004); whereas, both RS and CS were strongly associated with the interventricular septum thickness (RS: R=0.248, p=0.003; CS: R= −0.192, p=0.023) and relative wall thickness (RS: R=0.178, p=0.036; CS: R= −0.184, p=0.030) but not with EATV; on multiple regression analysis, EATV was a predictor of GLS independent of age, male gender, BMI, diabetes, hyperlipidemia, hypertension and CAD (Adjusted R2=0.238, p<0.001).

Conclusion

EATV is independently associated with GLS despite the preserved LVEF and lacking of obstructive CAD, and may play a significant role in estimating impaired longitudinal LV performance.

Spinal Alignments of Residual Lumbar Curve Affect Disc Degeneration after Spinal Fusion in Patients with Adolescent Idiopathic Scoliosis: Follow-up after 5 or More Years

Introduction

Despite preserving lumbar disc mobility, spinal sagittal, and/or coronal alignment might ultimately impede surgical success. The purpose of this study was to elucidate the effects of spinal alignment on lumbar disc degeneration after 5 or more years in adolescent idiopathic scoliosis (AIS) patients who underwent spinal fusion.

Methods

Subjects were 49 AIS patients who underwent posterior spinal fusion without lumbar curve fusion. The inclusion criteria were the following: 1) Lenke type 1A, 1B, 2A or 2B, 2) age 10 to 19 years at the time of operation, and 3) minimum 5-year follow-up. The exclusion criteria were the following: 1) diagnosed as other than AIS, 2) history of lumbar disc herniation and spondylolysis, 3) subsequent surgery, and 4) history of surgery before AIS surgery. Nineteen patients agreed to participate in this research. X-rays, lumbar MRI, and questionnaires were evaluated. Disc degeneration in non-fused segments was defined as Pfirrmann grade 3 or higher. Patients with disc degenerations at the final observation (DD[+] group) were compared to those without disc degenerations (DD[−] group).

Results

There were no significant differences in the preoperative or postoperative 1-week X-ray parameters between both groups. The lumbar curve was significantly larger in the DD[+] group compared with the DD[−] group at the final observation (DD[+]: 16.8 degrees, DD[−]: 10.4 degrees, p = 0.035). The sagittal vertical axis (SVA) was significantly larger in the DD[+] group compared with the DD[−] group at the final observation (DD[+]: −4.4 mm, DD[−]: −34.3 mm, p = 0.006). SRS-22 function, self-image, and satisfaction scores were lower in the DD [+] group compared with the DD[−] group at the final observation.

Conclusions

The patients with DD had significantly larger lumbar curve and SVA with lower SRS-22 function, self-image, and satisfaction scores at the final observation. Even though the non-fused segments were preserved, spinal alignments of non-fused lumbar curve affect the DDs.

Hooks at the Upper Instrumented Vertebra Can Adjust Postoperative Shoulder Balance in Patients with Adolescent Idiopathic Scoliosis: 5 Years or More of Follow-up

Study Design

A retrospective cohort study.

Purpose

This study aims to investigate postoperative shoulder imbalance (PSI) ≥5 years postoperatively in patients who underwent posterior spinal fusion using hooks at the upper instrumented vertebra (UIV) for Lenke type 1 adolescent idiopathic scoliosis (AIS).

Overview of Literature

Studies have reported PSI due to excessive correction of the main thoracic curve.

Methods

We examined 56 patients with AIS who underwent a posterior spinal fusion with hooks at the UIV from 2004 to 2010. Of these, we enrolled 14 patients who underwent surgery, at least, 5 years ago. X-rays and Scoliosis Research Society-22 (SRS-22) questionnaire were administered. To evaluate the shoulder balance, T1 vertebral tilt angle (T1 tilt), clavicle angle, and radiographic shoulder height (RSH) were measured. PSI was considered as the absolute value of the postoperative RSH being ≥20 mm. Based on radiographs obtained immediately postoperatively, we divided patients into two groups as follows: the balanced group (absolute value of RSH <20 mm) and imbalanced group (absolute value of RSH ≥20 mm).

Results

The frequency of PSI was 28.6% immediately postoperatively, 0% 2 years postoperatively, and 7.1% at the last follow-up. In the balanced group, PSI did not occur even at 2 years postoperatively or at the last follow-up. In the imbalanced group, PSI was improved in all patients 2 years postoperatively and all patients, except one patient, at the last follow-up. No significant differences were noted in the frequency of distal adding-on at 2 years postoperatively or the last follow-up between the balanced group and the imbalanced group. We observed moderate negative correlations between the absolute value of T1 tilt and the SRS-22 pain and satisfaction at the last follow-up.

Conclusions

Hooks at the UIV could adjust the shoulder balance to avoid long-term PSI in patients with AIS.

Thoracic Deformity Correction and Changes of Vital Capacity, Forced Expiratory Volume in 1 Second, and Expiratory Flow in Adolescent Idiopathic Scoliosis Five Years or More after Posterior Spinal Fusion with Thoracoplasty

Introduction

The purpose of this study is to investigate thoracic deformity correction and pulmonary function changes in patients with adolescent idiopathic scoliosis (AIS) five years or more after undergoing posterior spinal fusion with thoracoplasty for correction of a thoracic deformity.

Methods

Subjects were 57 patients with AIS who underwent posterior spinal fusion between 2004 and 2010. 24 patients who had undergone thoracoplasty at least five years earlier agreed to participate in this research. X-rays, pulmonary function tests, and thoracic cage computed tomography (CT) were performed, and the Scoliosis Research Society Outcomes Questionnaire (SRS-22) was administered. CT axial images were used at the apex of the main thoracic (MT) curve. Apical vertebral rotation was evaluated using rotation angle to the sagittal plane (RA_sag). Thoracic deformities were evaluated using the rib hump index (RHi) and the posterior hemithoracic symmetry ratio (PHSr).

Results

There were no significant differences between the preoperative and the final observation forced vital capacity (FVC) or the preoperative and the final observation %FVC. The forced expiratory volume in 1 s (FEV1) and %FEV1 were significantly improved at the final observation: FEV1 (preoperative: 1.88 L, final observation: 2.05 L, p = 0.045) and %FEV1 (preoperative: 57.1%, final observation: 66.2%, p = 0.001). FEV1/FVC was also significantly improved at the final observation (preoperative: 83.0%, final observation: 86.4%, p = 0.019). The peak expiratory flow (PEF) was significantly improved at the final observation (preoperative: 3.67 L/s, final observation: 4.38 L/s, p = 0.029). On the CT assessment for thoracic deformities, there were no significant changes in RA_sag or RHi. PHSr was significantly increased at the final observation compared with the preoperative period.

Conclusions

With posterior spinal fusion in combination with thoracoplasty for AIS, although the correction of deformities was limited, the pulmonary function testing demonstrated the preservation of vital capacity (VC) and improvements in the forced expiratory volume in 1 s and expiratory flow.

Safety and Efficacy of Percutaneous Pedicle Screw Placement Using a Power Tool

Introduction

This study compared traditional manual methods and power tool use with regard to the speed and accuracy of percutaneous pedicle screw (PPS) placement and determined the advantages associated with the use of power tools.

Although the indication of PPS placement in minimally invasive spine stabilization (MISt) procedures has been recently expanded, there are no reports on PPS insertion using a power tool.

Methods

We evaluated 35 patients who underwent PPS insertion using a power tool during MISt procedures. On one side, PPS insertion was performed using the manual (M) method, whereas on the contralateral side, insertion was performed using the power tool (P) method. We assessed the number of implanted PPSs, time taken to implant PPSs after guidewire insertion, and accuracy of PPS placement as ranked postoperatively using computed tomography images.

Results

A total of 294 PPSs were inserted (147 using the M method and 147 using the P method). The mean PPS insertion time was 10.5 s using the P method and 27.4 s using the M method. The time required for inserting a screw using the P method remained consistent in the range of 10-15 s, whereas the time using the M method tended to increase from the second screw onward, with a range of 25-30 s. With regard to PPS insertion accuracy, a 2 mm or more pedicle breach was noted in 2 (1.4%) case after the P method and in 2 (1.4%) case after the M method.

Conclusions

PPS placement using power tools has the potential to save the surgical time during MISt procedures.

Quantification of L5 radiculopathy due to foraminal stenosis using three-dimensional magnetic resonance myelography

Introduction

This study aimed to evaluate morphological changes in the L5 nerve roots in control and symptomatic patients using magnetic resonance myelography [MRM]. Moreover, the utility of MRM for the diagnosis of intraforaminal or extraforaminal lesions in patients with L5 radiculopathy was evaluated using healthy subjects as controls.

Methods

Of 270 subjects who underwent MRM of the lumbar spine at our institution between April 2007 and December 2010, 135 patients (78 men and 57 women; average age: 61.3 years) with no history of spinal surgeries and nerve roots without infections, tumors, or malformations were selected for this study.

The end-point measurements included the bifurcation angle of inclination (proximal tilting angle [PTA]) of the L5 nerve root as observed via MRM, lateral angle of inclination (lateral tilting angle [LTA]), bifurcation diameter (proximal nerve root width [PW]), and dorsal root ganglion (DRG) diameter (DRG width [DW]). DW ratio was then calculated for healthy controls and symptomatic subjects. We measured each parameter using the image information unification system ShadeQuest (Yokogawa, Tokyo, Japan). Two spinal surgeons conducted the magnetic resonance imaging evaluation.

Results

Swelling of the L5 DRG was detected in cases with intraforaminal or extraforaminal stenosis. With regard to the cutoff value of 6.5 mm for L5 DW, foraminal stenosis can be confirmed if DW is ≥6.5 mm or more via MRM. In cases where L5 DRG was swollen to ≥1.2 times the size in healthy subjects, L5 radiculopathy with foraminal lesions can be diagnosed.

Conclusions

Our findings indicated that 3D MRM is a noninvasive technique and a useful tool for the diagnosis of intraforaminal or extraforaminal lesions in the lumbar spine. Therefore, it can be combined with other diagnostic methods used for the identification of intraforaminal or extraforaminal L5 nerve root lesion.

Spinal fusion on adolescent idiopathic scoliosis patients with the level of L4 or lower can increase lumbar disc degeneration with sagittal imbalance 35 years after surgery

Introduction

The purpose of this study was to investigate the long-term incidence of lumbar disc degeneration and Modic changes in the non-fused segments of patients with adolescent idiopathic scoliosis (AIS) who previously underwent spinal fusion.

Methods

Study subjects consisted of 252 patients with AIS who underwent spinal fusion between 1968 and 1988. Of 252 patients, 35 subjects underwent lumbar spine MRI and whole spine X-ray examination. The mean patient age at the time of follow-up was 49.8 years, with an average follow-up period of 35.1 years. We classified the subjects into two groups based on the lowest fused vertebra: H group whose lowest fused vertebra was L3 or higher levels and L group whose lowest fused vertebra was L4 or lower levels.

Results

The L group had significantly advanced disc degeneration on MRI. There was no significant difference between two groups in Modic changes. The L group showed less lumbar lordosis than the H group (H group: 48.1 degrees; and L group: 32.1 degrees) and greater SVA (H group: 1.2 cm; and L group: 5.5 cm).

Conclusions

In AIS patients, 35 years after spinal fusion surgery on average, we evaluated lumbar disc degeneration and Modic changes of the non-fused segments. In patients with the lowest fusion level at L4 or lower, there were reduced lumbar lordosis, considerable SVA imbalance, and severe disc degeneration compared with those with the lowest fusion level at L3 or higher. The lowest fusion level at L3 or higher is recommended to reduce disc degeneration in midlife.

Midlife changes of health-related quality of life in adolescent idiopathic scoliosis patients who underwent spinal fusion during adolescence

PURPOSE

Our previous study reported a good health-related quality of life (HRQOL) in adolescent idiopathic scoliosis (AIS) patients 21 years or more after surgery. The purpose of this study is to investigate midlife changes in HRQOL among AIS patients who passed further 5 years from the previous survey.

METHODS

Subjects were 252 individuals who underwent spinal fusion for AIS between 1968 and 1988. The survey was administered twice-in 2009 and in 2014 using Scoliosis Research Society Patient Questionnaire (SRS-22). We analysed survey responses from 42 individuals (39 females, 3 males) who responded to both surveys.

RESULTS

The average scores for each respective domain of the SRS-22 in 2009 and 2014, respectively, were: function, 4.3 and 4.2; pain, 4.3 and 4.3; self-image, 3.0 and 2.9; mental, 3.9 and 3.8; satisfaction, 3.6 and 3.5. There were no significant differences in any domain of the SRS-22 between 2009 and 2014. Comparing non-fused segments of the lumbar spine of patients with fewer than four discs remaining with patients with four discs or more remaining, SRS-22 satisfaction score decreased more in patients with fewer than four discs (change in patients with four discs or more: -0.02; change in patients with fewer than four discs: -0.38; P = 0.05).

CONCLUSION

Each SRS-22 subscore was similar between 2009 and 2014 surveys. Those scoliosis patients who underwent spinal fusion during adolescence had good HRQOL scores in midlife. Even after five years passed, good conditions were maintained.

Actinomyces denticolens colonisation identified in equine tonsillar crypts

Recently, submandibular abscesses associated with Actinomyces denticolens have been reported in horses. The actinomycotic clumps have been observed in the tonsillar crypts. The aim of this study was to demonstrate colonisation of A denticolens in equine tonsils. Twelve equine tonsils obtained from a slaughterhouse were divided into two parts for histopathological examination and for isolation of A denticolens. When actinomycotic clumps were found in these tonsillar crypts, immunohistochemistry using hyperimmune serum against A denticolens (DMS 20671) was performed on the serial sections. To determine whether Actinomyces-like bacteria isolated using immunoantigenic separation technique were A denticolens, the isolates were analysed for the 16S rRNA gene sequence. Actinomycotic clumps were found in the tonsillar crypts of 11 (91.7 per cent) horses. The clumps were of the saprophytic type accompanied with the feedstuffs, but a few clumps were surrounded by inflammatory cells. A denticolens antigens were immunodetected not only in the clumps of 11 (100 per cent) tonsils, but also in the tonsillar parenchyma. Six isolates obtained from four tonsils showed 99.7–99.9 per cent similarity to A denticolens in the 16S rRNA gene sequence. In horses, the colonisation sites of A denticolens are the tonsils, thus the authors suggest that the tonsils provide the intrinsic infection site for A denticolens.

The problems of cervical conization for postmenopausal patients

PURPOSE

Cervical conization is the definitive treatment for women of any age who have cervical intraepithelial neoplasia (CIN). However, complications of the procedure have not been fully investigated in postmenopausal patients. The aim of this retrospective study was to evaluate the results and complications of cervical conization performed on premenopausal and postmenopausal patients.

MATERIALS AND METHODS

This study recruited 405 patients who had undergone cervical laser conization. The median age was 36 years (range 20 to 75), and there were 361 (89.1%) premenopausal and 44 (10.9%) postmenopausal women.

RESULTS

The length of the cone removed from the postmenopausal patients was significantly longer than the length from the premenopausal patients (17.9 ± 3.9 mm vs. 15.7 ± 3.6 mm, respectively; p = 0.02). The rate of positive endocervical cone margins from the premenopausal patients was significantly higher than the rate from the postmenopausal patients (9.1% vs. 0%, respectively; p = 0.037). The rate of cervical stenosis was significantly higher in postmenopausal patients than in premenopausal patients (59.1% vs. 8.3%; respectively; p < 0.0001). There was no difference in the rates of frequency of intraoperative complications.

CONCLUSIONS

Although deep incision is mandatory for complete excision of CIN in postmenopausal patients, it increases the incidence of cervical stenosis. Cervical conization may be a less invasive surgical procedure for older women with CIN than hysterectomy; however, the risk of postoperative complications remains, causing a dilemma for physicians treating postmenopausal women with CIN.

Effectiveness of a simulated patient training programme based on trainee response accuracy and appropriateness of feedback

INTRODUCTION

Simulated patients (SPs) need education and training in required skills to be effective resources in education. This study was conducted to examine the effectiveness of an SP training programme based on the accuracy of trainee responses and the appropriateness of their feedback.

METHODS

Thirty-two applicants to the training programme and 35 experienced SPs were included in this study. The experienced SPs served as a reference group. The rate of accurate responses and the rate of appropriate feedback were assessed with pre- and post-training tests, and these two outcome measures were compared with those of the experienced SPs.

RESULTS

No significant differences were found in trainee response accuracy or appropriateness of feedback between pre- and post-training tests. The response accuracy rate of the trainees on the pre-training test was significantly lower than that of SPs with 1-2 years of experience, whilst there was no significant difference between these SPs and the trainees on the post-training test.

CONCLUSIONS

Although our study suggests that more training is needed to improve the skills of SPs, the training programme may contribute to helping trainees reach a novice level in the skill of providing accurate responses. SP training should be encouraged to contribute to the effectiveness of such teaching and to establish the validity of the assessment.

Anti-interferon-α neutralizing antibody is associated with nonresponse to pegylated interferon-α plus ribavirin in chronic hepatitis C

Pegylated interferon-α (PEG-IFN-α) plus ribavirin (RBV) treatment fails to achieve a sustained virological response (SVR) in approximately 20-50% of patients with chronic hepatitis C virus (HCV) infection. We assessed the contribution of an anti-IFN-α neutralizing antibody (NAb) on the nonresponse to treatment. NAbs were detected using an antiviral assay that assessed the neutralizing effects of serum samples against IFN. Serum samples were obtained at the end of the treatment and evaluated for the presence of NAbs using recombinant IFN-α as a standard. We studied 129 PEG-IFN-α/RBV-treated patients. In the 82 end-of-treatment responders, no NAbs were detected. Of the 47 patients who did not respond, seven (15%) were positive for NAbs. We also examined an additional 83 patients who had not responded to PEG-IFN-α treatment, and detected 12 with NAbs. Patients with good IFN-responsive characteristics, including HCV genotype 2/3 and major allele homozygotes for interleukin-28B, were included in the 19 patients with NAbs. No NAbs interfered with the antiviral activity of natural human IFN-β (nIFN-β) and re-treatement of patients with NAbs with nIFN-β/RBV achieved SVR. Our analyses revealed that the emergence of anti-IFN-α NAbs was a candidate causal factor of PEG-IFN-α-treatment failure. Therefore, these antibodies should be assayed in patients who do not respond to PEG-IFN-α therapy, and if detected, other effective treatments, i.e., medications that are not neutralized by anti-IFN-α NAbs, should be considered.

Self-assembled Nano-layering at the Adhesive Interface

According to the ‘Adhesion–Decalcification’ concept, specific functional monomers within dental adhesives can ionically interact with hydroxyapatite (HAp). Such ionic bonding has been demonstrated for 10-methacryloyloxydecyl dihydrogen phosphate (MDP) to manifest in the form of self-assembled ‘nano-layering’. However, it remained to be explored if such nano-layering also occurs on tooth tissue when commercial MDP-containing adhesives (Clearfil SE Bond, Kuraray; Scotchbond Universal, 3M ESPE) were applied following common clinical application protocols. We therefore characterized adhesive-dentin interfaces chemically, using x-ray diffraction (XRD) and energy-dispersive x-ray spectroscopy (EDS), and ultrastructurally, using (scanning) transmission electron microscopy (TEM/STEM). Both adhesives revealed nano-layering at the adhesive interface, not only within the hybrid layer but also, particularly for Clearfil SE Bond (Kuraray), extending into the adhesive layer. Since such self-assembled nano-layering of two 10-MDP molecules, joined by stable MDP-Ca salt formation, must make the adhesive interface more resistant to biodegradation, it may well explain the documented favorable clinical longevity of bonds produced by 10-MDP-based adhesives.