Comparison of pedicle screw placement accuracy between two types of imaging support (Artis Zeego versus two-dimensional fluoroscopy): a cross-sectional observational study.

BACKGROUND: The pedicle screw system is widely used in spine surgery, and it provides rigid fixation and leads to successful subsequent deformity correction and bony fusion. The standard imaging technique for pedicle screw insertion is two-dimensional images obtained from C-arm-type X-ray fluoroscopy. Artis Zeego is an emerging intraoperative imaging technique that can provide conventional two-dimensional fluoroscopic images and rapid three-dimensional fluoroscopic computed tomography reconstruction imaging. The aim of this study is to compare the insertion accuracies of PS placement using Artis Zeego and conventional 2D X-ray fluoroscopy. METHODS: In this study, we retrospectively reviewed the postoperative images of thoracolumbar fusion patients who underwent surgery using pedicle screws between 2013 and 2018. Pedicle screw malplacement was assessed using a four-grade classification by Rao et al. Misplacement rates were compared between pedicle screws assisted with Artis Zeego and two-dimensional fluoroscopy. RESULTS: A total of 1107 pedicle screws in 153 patients were inserted using Artis Zeego, and 427 pedicle screws in 80 patients were inserted using fluoroscopy. The overall perforation rate was 4.2% (46 perforations of 1106 pedicle screws) in the Artis Zeego group and 7.7% (33 perforations of 427 pedicle screws) in the fluoroscopy group. In the Artis Zeego group, 43 (3.9%) screws were classified as grade 1, and three (0.3%) screws were classified as grade 2. In the fluoroscopy group, 21 (4.9%) screws were classified as grade 1, 10 (2.3%) screws were classified as grade 2, and 2 (0.5%) screws were classified as grade 3. The use of Artis Zeego was associated with a significantly lower screw malplacement rate than was the use of fluoroscopy (p < 0.001). CONCLUSIONS: Our results demonstrated that pedicle screw placement with Artis Zeego was associated with a lower malplacement rate than was conventional two-dimensional fluoroscopy. No severe malplacement was observed in the Artis Zeego group. Thus, Artis Zeego could be a good option for improving pedicle screw accuracy.

The new international tax regime: analysis from a power-basis perspective.

Scholars of international relations have not cultivated the groundwork of international taxation. However, the Organization for Economic Cooperation and Development's Base Erosion and Profit Shifting (BEPS) Project, Post-BEPS, and the Common Reporting Standard system, have attracted political attention on an international level. The purpose of this paper is to explain the recently formed and still being formed international tax regime by applying international regime theory from a power-based perspective. This study addresses the regime in two aspects: tax rulemaking and tax administration. The author uses qualitative discussion, breaking down the recent international tax regime issues for each sub-regime. Through the discussion, this research implies that major economic powers, pressures of fear of being labeled uncooperative, the force of theoretically grounded idea regarding a fundamental international tax principle, and the desperate need for tax authorities to ensure taxpayer and money flow transparency, are assisting the formulation of the new international tax regime.

Radiological features of cervical spine in dropped head syndrome: a matched case-control study.

PURPOSE: Dropped head syndrome (DHS) is presumably caused by focal myopathy in the cervical posterior muscles; however, distinguishable radiological features of the cervical spine in DHS remain unidentified. This study investigated the radiological features of the cervical spine in dropped head syndrome. METHODS: The records of DHS patients and age- and sex-matched cervical spondylotic myelopathy (CSM) patients were reviewed. Cervical spinal parameters (C2-7, C2-4, and C5-7 angles) were assessed on lateral cervical spine radiographs. Quantitative radiographic evaluation of cervical spine degeneration was performed using the cervical degenerative index (CDI), which consists of four elements: disk space narrowing (DSN), endplate sclerosis, osteophyte formation, and listhesis. RESULTS: Forty-one DHS patients were included. Statistically significant differences were noted between the upper and lower cervical spine in the sagittal angle parameters on the neutral, flexion, and extension radiographs in DHS group, whereas no significant differences were observed in CSM group. CDI comparison showed significantly higher scores of DSN in C3/4, C4/5, C5/6, and C6/7; sclerosis in C5/6 and C6/7; and osteophyte formation in C4/5, C5/6, and C6/7 in DHS group than in CSM group. Comparison of listhesis scores revealed significant differences in the upper levels of the cervical spine (C2/3, C3/4, and C4/5) between two groups. CONCLUSION: Our results demonstrated that the characteristic radiological features in the cervical spine of DHS include lower-level dominant severe degenerative change and upper-level dominant spondylolisthesis. These findings suggest that degenerative changes in the cervical spine may also play a role in the onset and progression of DHS.

The effect of denosumab on pedicle screw fixation: a prospective 2-year longitudinal study using finite element analysis.

BACKGROUND: Pedicle screw loosening is a major complication following spinal fixation associated with osteoporosis in elderly. However, denosumab is a promising treatment in patients with osteoporosis. The effect of denosumab on pedicle screw fixation is unknown. Therefore, we investigated whether denosumab treatment improves pedicle screw fixation in elderly patients with osteoporosis. METHODS: This was a 2-year prospective open-label study. From February 2015 to January 2016, we included 21 patients with postmenopausal osteoporosis who received initial denosumab treatment. At baseline, 12 months, and 24 months, we measured volumetric bone mineral density (BMD) using quantitative computed tomography (QCT) and performed CT-based finite element analysis (FEA). Finite element models of L4 vertebrae were created to analyze the bone strength and screw fixation. RESULTS: BMD increased with denosumab treatment. FEA revealed that both pullout strength of pedicle screws and compression force of the vertebra increased significantly at 12 and 24 months following denosumab treatment. Notably, pullout strength showed a stronger correlation with three-dimensional volumetric BMD around pedicle screw placement assessed by QCT (r = 0.83, at 24 months) than with two-dimensional areal BMD assessed by dual energy X-ray absorptiometry (r = 0.35, at 24 months). CONCLUSION: To our knowledge, this is the first study to reveal that denosumab treatment achieved strong pedicle screw fixation with an increase in BMD around the screw assessed by QCT and FEA; therefore, denosumab could be useful for osteoporosis treatment during spinal surgery in elderly patients with osteoporosis.

Lateral lumbar interbody fusion in revision surgery for restenosis after posterior decompression.

OBJECTIVE: The purpose of this study was to compare the clinical results of revision interbody fusion surgery between lateral lumbar interbody fusion (LLIF) and posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF) with propensity score (PS) adjustments and to investigate the efficacy of indirect decompression with LLIF in previously decompressed segments on the basis of radiological assessment. METHODS: A retrospective study of patients who underwent revision surgery for recurrence of neurological symptoms after posterior decompression surgery was performed. Postoperative complications and operative factors were evaluated and compared between LLIF and PLIF/TLIF. Moreover, postoperative improvement in cross-sectional areas (CSAs) in the spinal canal and intervertebral foramen was evaluated in LLIF cases. RESULTS: A total of 56 patients (21 and 35 cases of LLIF and PLIF/TLIF, respectively) were included. In the univariate analysis, the LLIF group had significantly more endplate injuries (p = 0.03) and neurological deficits (p = 0.042), whereas the PLIF/TLIF group demonstrated significantly more dural tears (p < 0.001), surgical site infections (SSIs) (p = 0.02), and estimated blood loss (EBL) (p < 0.001). After PS adjustments, the LLIF group still showed significantly more endplate injuries (p = 0.03), and the PLIF/TLIF group demonstrated significantly more dural tears (p < 0.001), EBL (p < 0.001), and operating time (p = 0.04). The PLIF/TLIF group showed a trend toward a higher incidence of SSI (p = 0.10). There was no statistically significant difference regarding improvement in the Japanese Orthopaedic Association scores between the 2 surgical procedures (p = 0.77). The CSAs in the spinal canal and foramen were both significantly improved (p < 0.001). CONCLUSIONS: LLIF is a safe, effective, and less invasive procedure with acceptable complication rates for revision surgery for previously decompressed segments. Therefore, LLIF can be an alternative to PLIF/TLIF for restenosis after posterior decompression surgery.

Risk factors predicting osteosarcopenia in postmenopausal women with osteoporosis: A retrospective study.

There is growing interest in "osteosarcopenia" as the coexistence of osteoporosis and sarcopenia exacerbates negative outcomes. However, limited information is available regarding the risk factors of osteosarcopenia development in patients with osteoporosis. Therefore, we retrospectively reviewed 276 consecutive patients with postmenopausal osteoporosis who regularly visited Showa University Hospital. Patients were eligible for the study if they were ≥65 years of age and underwent dual-energy X-ray absorptiometry, blood sampling, and physical performance assessment. Patients were divided into the osteosarcopenia and osteoporosis alone groups according to the diagnostic criteria of the Asian Working Group for Sarcopenia. Of the 276 patients with osteoporosis, 54 patients (19.6%) had osteosarcopenia. Patients in the osteosarcopenia group had a greater risk of frailty than did those in the osteoporosis alone group (odds ratio 2.33; 95% confidence interval, 1.13-4.80, P = 0.028). Low body mass index seemed to be the strongest factor related to the development of osteosarcopenia, and none of the patients in the osteosarcopenia group were obese (BMI ≥27.5 kg/m2). Multiple logistic analyses revealed that patients aged 65-74 years who had comorbidities such as kidney dysfunction and high levels of HbA1c were at risk of developing osteosarcopenia. Thus, we strongly recommend the assessment of the key components of the diagnosis of osteosarcopenia in an osteoporosis clinic for patients with low body mass index. Furthermore, appropriate assessments, including comorbidities, will help in identifying patients at greater risk of developing osteosarcopenia.

Impact of Spinopelvic sagittal alignment on the surgical outcomes of dropped head syndrome: a multi-center study.

BACKGROUND: Most of the previous studies about the surgical treatment of dropped head syndrome (DHS) are small case series, and their primary outcome measures were cervical alignment parameters. Therefore, little is known about the associations between pre- and postoperative global sagittal alignment in the whole spine and the clinical outcomes of the surgical treatment of DHS. In this study, we investigated the surgical outcomes of DHS, including correction of cervical and global spinal sagittal alignment. METHODS: This study was a retrospective observational study. Fifteen patients with DHS who had undergone correction surgery were enrolled. Surgical outcomes, including complications and implant failures, were investigated. We assessed cervical alignment parameters as well as spinopelvic global alignment parameters, including pelvic incidence (PI), lumbar lordosis (LL), and C7-sacral sagittal vertical axis (SVA). We examined the changes in these parameters using pre- and posoperative whole spine lateral radiographs. The parameters were compared between the failure and nonfailure groups. RESULTS: Recurrence of sagittal imbalance and horizontal gaze difficulty was observed in 6 cases (40%). In all, 3 cases (20%) exhibited a distal junctional failure and required multiple surgeries with extension of fusion. Of all the radiographic parameters compared between the failure and nonfailure groups, significant differences were only observed in pre and postoperative SVA and PI-LL. CONCLUSIONS: Our results suggest that the global sagittal alignment parameters, including PI-LL and SVA, were different between the patients with failure and non failure, and these parameters might have notable impacts on surgical outcomes. Surgeons should consider PI-LL and SVA while determining the surgical course for patients with DHS.

Analysis of three-dimensional bone mineral density and bone strength measured by quantitative computed tomography following denosumab discontinuation in a patient with postmenopausal osteoporosis.

Discontinuation of denosumab during osteoporosis treatment leads to rapid loss of bone mineral density and induces a bone turnover rebound effect. Previous studies have reported analysis based on dual-energy X-ray absorptiometry scanning (DXA). Here, we report the first case involving analysis of three-dimensional bone mineral density and bone strength, measured by quantitative computed tomography (QCT) after discontinuation of denosumab. An 82-year-old woman who discontinued denosumab because of patient's wish was administered the fifth dose after a gap of 14 months. Her bone mineral density evaluated by DXA and QCT, bone strength, and bone turnover marker levels showed significant rebound phenomenon. The levels of the cortical parameters of the hip were also decreased indicating an increased risk of femoral fractures after denosumab interruption. Our case highlights the increased risk of fractures after discontinuation of denosumab. Therefore, denosumab must be used judiciously without interruption in the dosage schedule.

Overview of dropped head syndrome (Combined survey report of three facilities).

BACKGROUND: Dropped head syndrome (DHS) is a low prevalence and the clinical features remain unclear. The purpose of the present study was to clarify the general overview of DHS. METHODS: The subjects were 67 consecutive DHS patients (17 men and 50 women; average age 72.9 ± 10.2 years) presenting difficulty of horizontal gaze in up-right position. The patients' background, global spinal alignment, clinical findings and treatment were analyzed. RESULTS: The peak population of DHS was 75-79-year-old females. The comorbidities included Parkinson's disease in 9 cases, minor trauma in 9 cases, post-cervical operation in 3 cases, mental depression in 3 cases, malignant tumor in 3 cases, diabetes mellitus in 2 cases and rheumatoid arthritis in 2 cases. The C2-C7 cervical coronal vertical axis was distributed more to the right side (2.6 ± 12.8 mm). Regarding sagittal alignment, 24 cases (35.8%) showed negative balanced DHS (N-DHS) and 43 cases (64.2%) showed positive balanced DHS (P-DHS). There were significant differences in C2-C7 angle, T1S, LL and PI-LL between the two groups. Cervical or back pain was present in 62 cases (92.5%), and average numerical rating scale was 3.0 ± 2.6. Fourteen cases (20.9%) recovered (average 11.3 months), but 29 cases (43.3%) did not recover without surgery. Twenty-four cases (35.8%) underwent surgery, 20 for cervical spine and 4 for thoraco-lumbar spine, and horizontal gaze difficulty was improved in all patients post-surgery. CONCLUSION: DHS was mainly observed in elderly women. About 20% of DHS patients recovered without surgical treatment. DHS was accompanied by scoliosis in 37.3% of the cases.

A Novel Method for the Prediction of the Pedicle Screw Stability: Regional Bone Mineral Density Around the Screw.

STUDY DESIGN: Prospective feasibility study on consecutive patients. OBJECTIVE: The aim of this study was to investigate the ability of regional BMD around the pedicle screw to predict the screw fixation. SUMMARY OF BACKGROUND DATA: Pedicle screw fixation is the gold standard technique for spinal fusion. Despite the advantage of biomechanical stability, screw loosening is a common complication. In previous studies, pullout strength and screw insertional torque were correlated, and most importantly, affected by bone mineral density (BMD). Although the density and structure of the vertebral body are not homogeneous, no study has yet evaluated the relationship between screw insertional torque and regional BMD around the pedicle screw in vivo. METHODS: Consecutive 50 patients, scheduled for transpedicular fixation, were evaluated preoperatively for BMD measured by dual-energy absorptiometry (DXA) and quantitative computed tomography (QCT). Regional volumetric BMD around the pedicle screw (PS-vBMD) using the novel QCT technique was also evaluated. Among all patients, 190 screws (diameter, 7.5 to 8.5 mm; length, 40 to 45 mm, inserted from L1 to L5) were eligible for this study and were analyzed to identify factors contributing to insertional torque. The following factors were investigated: age, body mass index, laboratory data, pedicle diameter, screw diameter, screw length, and 5 types of bone mineral density measures [DXA: spine-areal BMD (aBMD), total hip-aBMD, femoral neck-aBMD, QCT: central-vBMD, PS-vBMD]. RESULTS: Insertional torque was significantly correlated with each BMD measurement and strongest with PS-vBMD (r=0.61, P<0.001). Multiple regression analysis showed PS-vBMD was most strongly correlated with screw insertional torque (stdß=0.494; P<0.001). A model containing the following 5 predictors was significantly associated with screw insertional torque: age, pedicle diameter, screw diameter, screw length, and PS-vBMD. CONCLUSIONS: The preoperative measurement of PS-vBMD was technically feasible and reliably predictive of screw insertional torque during transpedicular fixation in a clinical setting.

A Case of Successful Foraminotomy for Severe Bilateral C5 Palsy following Posterior Decompression and Fusion Surgery for Cervical Ossification of Posterior Longitudinal Ligament.

We report a very rare (5~7%) case of bilateral C5 palsy after cervical surgery. A 71-year-old male patient with cervical ossification of posterior longitudinal ligament (OPLL) with foraminal stenosis at bilateral C4/5 underwent posterior decompression and fusion surgery. After surgery, muscle weakness in his both deltoid and biceps was detected and gradually deteriorated to complete paralysis. Postoperative MRI showed sufficient decompression of the spinal cord and posterior shifting. Subsequently, an additional bilateral foraminotomy at C4/5 was performed, with a suspicion that bilateral foraminal stenosis at C4/5 may have been the cause of the paresis. After foraminotomy, muscular contraction was seen in both deltoid and biceps. Finally, complete motor recovery was achieved in a year. Although the gold standard procedure for the prevention and treatment of postoperative C5 palsy has not yet been established, an additional foraminotomy may be recommended for severe C5 palsy in cases of foraminal stenosis even after the occurrence of palsy.

[A case of myxofibrosarcoma of the bladder].

A 43-year-old woman presented to our hospital with the chief complaints of gross hematuria and dysuria. Cystoscopy and magnetic resonance imaging showed a tumor on the dome of the bladder and large blood clots. Computed tomography demonstrated no findings of distant metastasis. Following transurethral resection of the tumor, the tumor was histologically diagnosed as myxofibrosarcoma with muscular invasion, and partial cystectomy was performed in September 2009. There has been no evidence of recurrence or metastasis for 24 months postoperatively. In addition, the Japanese literature on myxofibrosarcoma of the bladder was reviewed and discussed.

[Two cases of urolithiasis induced by topiramate].

Topiramate is an antiepileptic medicine that has been used adjunctively in the treatment of refractory seizures in Japan since 2007. Topiramate has been shown to inhibit specific carbonic anhydrase activity in the kidney and may induce a distal type of renal tubular acidosis. Case 1 : A 22-year-old male was referred to our hospital after complaining of left flank pain. He developed a seizure disorder and had been using topiramate for 4 months. Drip infusion pyelography showed a left ureteral stone. Case 2 : A 7-year-old boy presented with gross hematuria. He developed West syndrome and had been using topiramate for 6 months. A computed tomographic scan showed a right kidney stone.

[Bilateral giant renal angiomyolipoma following hemodialysis in a patient with tuberous sclerosis].

A 49-year-old woman with tuberous sclerosis visited our hospital complaining of left abdominal pain. She had been diagnosed with bilateral renal angiomyolipoma (AML) when she was 32 years old and had been on maintenance hemodialysis since the age of 44. Magnetic resonance imaging showed bilateral giant renal AML and hemorrhage in the AML of the left kidney. Transthoracolumbar left nephrectomy was performed in March 2008. The resected specimen weighed 3.2 kg. The histological diagnosis was consistent with AML. In addition, the Japanese literature on giant renal AML was reviewed and discussed.

Temporal aspect of three visual search tasks by using TMS.

Transcranial magnetic stimulation (TMS) is applied as an important method to investigate human cognitive process. In this study, we used TMS to investigate temporal aspect of the right posterior parietal cortex involved in visual search. Subjects were required to respond as quickly and accurately as possible by pressing a mouse button to indicate the presence or absence of the target, and the reaction times were measured. Subjects received three experiments which the TMS stimulus onset asynchronies (SOA) were set as 100, 150 and 200 ms after visual stimulus presentation. When we examined the effects of TMS on pop-out visual search, there was a significant elevation in target-present reaction time when the TMS pluses were applied 150 ms after visual stimulus presentation. However for the other SOA cases and conjunction visual search task, there was no significant difference between no-TMS and TMS conditions. Therefore, we considered that the right posterior parietal cortex was involved in the pop-out visual search at about 150 ms after visual stimulus presentation.

TMS effect on visual search task.

In this study, we examined the temporal aspects of the right posterior parietal cortex in easy feature and hard feature "pop-out" visual searches using transcranial magnetic stimulation (TMS). The transcranial magnetic stimulations were applied over the right posterior parietal cortex of subjects. Subjects received 4 tests which the TMS onset times were set as 100, 150, 200 and 250 msec after visual stimulus presentation. We found that, when SOA=150 msec, compared to no-TMS condition, There was a significant elevation in response time when the TMS pluses were applied. However for the other SOA cases, there was no significant difference between TMS and no-TMS conditions. Therefore, we considered that "pop-out" visual search was processed in the right posterior parietal cortex at about 150 msec after stimulus present.

[Successful subtotal parathyroidectomy for giant tumor calcinosis with secondary hyperparathyroidism].

A 54-year-old woman was referred to our hospital for the treatment of secondary hyperparathyroidism due to chronic renal failure. She was on hemodialysis for 7 years and suffered from giant tumor calcinosis of the major joints associated with severe hypercalcemia and hyperphosphatemia. The largest one of the left hip joint caused gait disturbance. Medical therapy was unsuccessful and she underwent subtotal parathyroidectomy. After the operation, although the levels of serum calcium and phosphate were not normalized, the level of parathyroid hormone was lowered to the normal range. The volume of the tumor calcinosis gradually reduced and she became able to walk for a short distance 10 months after the operation.

[A case of incomplete distal renal tubular acidosis undergoing repeated treatment by extracorporeal shock-wave lithotripay and transureteral lithotripsy for recurrent urolithiasis].

A 65-year-old woman was referred to our hospital for further examination of recurrent urinary stone formation. She had undergone 49 sessions of extracorporeal shock-wave lithotripay (ESWL) and 3 sessions of transureteral lithotripsy (TUL) under the diagnosis of idiopathic recurrent urolithiasis at another hospital. An excretory urography showed bilateral hydronephrosis and a retrograde urography revealed bilateral lower ureteral stricture. Ammonium chloride loading test demonstrated incomplete distal renal tubular acidosis. Potassium citrate therapy had begun and bilateral nephrostomies were required in order to prevent recurrent urinary tract infection and new stone formation. Literature was reviewed and discussion was made on the ureteral stricture after ESWL and TUL, and on incomplete distal renal tubular acidosis.