Risk factors for preoperative neurological impairment in patients with spinal meningioma: A retrospective multicenter study.

BACKGROUND: Patients with spinal meningioma may present preoperatively with paralysis and sensory deficits. However, there is a paucity of detailed evaluations and a lack of consensus regarding imaging findings that are predictive of neurological symptoms in patients with spinal meningioma. METHODS: Herein, a total of 55 patients who underwent surgical resection of spinal meningiomas in eight hospitals between 2011 and 2021 were enrolled. Patient characteristics, degree of muscle weakness, sensory disturbances, and the presence of bowel/bladder dysfunction (BBD) before surgical treatment were evaluated using medical records. Patients with American Spinal Injury Impairment Scale grades A-C and the presence of BBD were classified into the paralysis (+) group. Patients with sensory disturbances were assigned to the sensory disturbance (+) group. Based on magnetic resonance (MR) and computed tomography images, the tumor location was classified according to the spinal level and its attachment to the dura mater. To evaluate tumor size, the tumor occupation ratio (OR) was calculated using the area and distance measurement method in horizontal MR images, and the maximum length and area of the tumor in the sagittal plane were measured. RESULTS: Of all patients, 85 % were women. The mean age of patients at surgery was 69.7 years. Twenty-eight (51 %) and 41 (75 %) patients were classified into the paralysis (+) and sensory disturbance (+) groups, respectively. The average tumor length and area in the sagittal plane were 19.6 mm and 203 mm2, respectively; OR-area and diameters were 70.3 % and 72.3 %, respectively. In univariate analyses, tumor length and area in the sagittal plane were significant risk factors for paralysis. OR-diameter, symptom duration, and a low MIB-1 index correlated with sensory disturbances. Multivariate logistic regression analysis demonstrated that the area and length of the tumor in the sagittal plane were significantly correlated with paralysis, whereas the OR-diameter and symptom duration significantly correlated with sensory disturbances. The cut-off values for the area and length of the tumor in the sagittal plane to predict paralysis were 243 mm2 and 20.1 mm, respectively. CONCLUSIONS: Preoperative paralysis in patients with spinal meningiomas was significantly associated with sagittal tumor size than with high tumor occupancy in the horizontal plane. Sensory disturbances were associated with high occupancy in the horizontal plane. Patients with spinal meningiomas > 20 mm in length or 243 mm2 in area in the sagittal plane are at risk of developing paralysis and could be considered for surgery even in the absence of paralysis.

IRIS U kit usefulness in transanal total mesorectal excision for lower rectal cancer to avoid urethral injury.

Transanal total mesorectal excision (taTME) has improved the laparoscopic dissection for rectal cancer in the narrow pelvis. Although taTME has more clinical benefits than laparoscopic surgery, such as a better view of the distal rectum and direct determination of distal resection margin, an intraoperative urethral injury could occur in excision ta-TME. This study aimed to determine the feasibility and efficacy of the ta-TME with IRIS U kit surgery. This retrospective study enrolled 10 rectal cancer patients who underwent a taTME with an IRIS U kit. The study endpoints were the safety of access (intra- or postoperative morbidity). The detectability of the IRIS U kit catheter was investigated by using a laparoscope-ICG fluorescence camera system. Their mean age was 71.4±6.4 (58-78) years; 80 were men, and 2 were women. The mean operative time was 534.6 ± 94.5 min. The coloanal anastomosis was performed in 80%, and 20% underwent abdominal peritoneal resection. Two patients encountered postoperative complications graded as Clavien-Dindo grade 2. The transanal approach with IRIS U kit assistance is feasible, safe for patients with lower rectal cancer, and may prevent intraoperative urethral injury.

Prognostic Factors after Surgical Treatment for Spinal Metastases.

STUDY DESIGN: A retrospective multicenter case series was conducted. PURPOSE: This study aimed to investigate survival and prognostic factors after surgery for a metastatic spinal tumor. OVERVIEW OF LITERATURE: Prognostic factors after spinal metastasis surgery remain controversial. METHODS: A retrospective multicenter study was conducted. The study participants included 345 patients who underwent surgery for spinal metastases from 2010 to 2020 at nine referral spine centers in Japan. Data for each patient were extracted from medical records. To identify the factors predicting survival prognosis after surgery, univariate analyses were performed using a Cox proportional hazards model. RESULTS: The mean age was 65.9 years. Common primary tumors were lung (n=72), prostate (n=61), and breast (n=39), and 67.8% (n=234) presented with osteolytic lesions. The epidural spinal cord compression scale score 2 or 3 was recognized in 79.0% (n=271). Frankel grade A paralysis accounted for 1.4% (n=5), and 73.3% (n=253) were categorized as intermediate or high risk according to the new Katagiri score. The overall survival rates were -71.0% at 6 months, 57.4% at 12, and 43.3% at 24. In the univariate analysis, Frankel grade A (hazard ratio [HR], 3.59; 95% confidence interval [CI], 1.23-10.50; p<0.05), intermediate risk (HR, 3.34; 95% CI, 2.10-5.32; p<0.01), and high risk (HR, 7.77; 95% CI, 4.72-12.8; p<0.01) in the new Katagiri score were significantly associated with poor survival. On the contrary, postoperative chemotherapy (HR, 0.23; 95% CI, 0.15-0.36; p<0.01), radiation therapy (HR, 0.43; 95% CI, 0.26-0.70; p<0.01), and both adjuvant therapy (HR, 0.21; 95% CI, 0.14-0.32; p<0.01) were suggested to improve survival. CONCLUSIONS: Surgical indications for patients with Frankel grade A or intermediate or high risk in the new Katagiri score should be carefully considered because of poor survival. Chemotherapy or radiation therapy should be considered after surgery for better survival.

Trends in patterns of treatment and survival of colorectal cancer patients using cancer registry data in Japan: 1995-2015.

Recent advances in treating colorectal cancer (CRC) have increased the importance of multidisciplinary treatment. This study aimed to clarify trends in the treatment and survival of CRC using population-based cancer registry data in Japan. We analyzed the survival of CRC cases diagnosed from 1995 through 2015 from a population-based cancer registry of six prefectures. The year of diagnosis was classified into five periods, and the trends in the detailed categorization of treatments and survival were identified. We calculated net survival and excess hazard of death from cancer using data on 256,590 CRC patients. The use of laparoscopic surgery has been increasing since 2005 and accounts for the largest proportion of treatment types in the most recent period. Net survival of CRC patients diagnosed after 2005 remained high for laparoscopic surgery and endoscopic surgery (endoscopic mucosal resection or endoscopic submucosal dissection). There was an upward trend in treatment with chemotherapy in addition to open and laparoscopic surgery. Using the excess hazard ratio at the regional stage since 2005, there has been a significant improvement in survival in the younger age group and the rectum cancer group. By type of treatment, there was a tendency toward significant improvement in the open surgery + chemotherapy group. We clarified the trends in treating CRC and the associated trends in survival. Continuous survey based on population-based data helps monitor the impact of developments in treatment.

A quantitative study of the development of taste pores in mice.

OBJECTIVES: This study determined the early development of taste buds by observing the changes in the three-dimensional structures of taste pores and microvilli in the circumvallate papillae (CVP) of mice, from pre- and postnatal stages to the adult stages. METHODS: Fragments of mouse CVP tissue were collected on embryonic day (E) 18 and postnatal days (P) 0, 3, 6, 7, 14, 21, 28, and 56. The surfaces of the tissue fragments located pore apertures via scanning electron microscopy, and the sizes of the CVP and maximum diameters of the pores were estimated from the recorded images. Likewise, changes in the structures of the epithelium around the pore aperture and microvilli protruding from the pores were examined. RESULTS: The size of the CVP exhibited a linear increase with age from E18 to P56. The epithelium around the pore aperture demonstrated changes to form microridges, indicating a characteristic pattern during CVP development. The size of the pore aperture also increased with age from E18 to P56. Furthermore, an increase in the number of pores with protruding microvilli was observed at the base of the epithelial trench. A significant positive correlation was observed between the maximum diameter of the pore and the size of the CVP. CONCLUSIONS: The expansion in the lateral view of the CVP was associated with the developmental stage from E18 to P56, suggesting that the growth of the CVP leads to the opening and enlargement of the taste pores with microvillus projections during these stages.

Fibroblast growth factor signalling regulates the development of tooth root.

Fibroblast growth factor (FGF) signalling plays a crucial role in the morphogenesis of multiple tissues including teeth. While the role of the signal has been studied in tooth crown development, little is known about root development. Of several FGF ligands involved in hard tissue formation, we suggest that FGF18 regulates the development of murine tooth roots. We implanted FGF18-soaked heparin beads into the lower first molar tooth buds at postnatal day 6 (P6), followed by transplantation under the kidney capsule. After 3 weeks, FGF18 significantly facilitated root elongation and periodontal tissue formation compared to the control. In situ hybridisation showed that Fgf18 transcripts were initially localised in the dental pulp along Hertwig's epithelial root sheath at P6 and P10 and subsequently in the dental follicle cells at P14. Fgf receptors were expressed in various dental tissues during these stages. In vitro analysis using the dental pulp stem cells revealed that FGF18 inhibited cell proliferation and decreased expression levels of osteogenic markers, Runx2, Alpl and Sp7. Consistently, after 1 week of kidney capsule transplantation, FGF18 application did not induce the expression of Sp7 and Bsp, but upregulated Periostin in the apical region of dental mesenchyme in the grafted molar. These findings suggest that FGF18 facilitates molar root development by regulating the calcification of periodontal tissues.

Trends in the stage distribution of colorectal cancer during the COVID-19 pandemic in Japan: a nationwide hospital-claims data analysis.

BACKGROUND: The COVID-19 pandemic has affected cancer care. The aim of this study was to clarify the trend of colorectal cancer (CRC) stage distribution in Japan during the COVID-19 pandemic. METHODS: In this retrospective study, we used an inpatient medical claims database established at approximately 400 acute care hospitals. From the database, we searched patients who were identified as having the main disease (using ICD-10codes [C18.0-C20]) between January 2018 and December 2020. A multivariate logistic regression analysis was used to determine the impact of the pandemic on CRC stage distribution each month, and the odds ratio (OR) for late-stage cancer was calculated. RESULTS: We analyzed 99,992 CRC patients. Logistic regression analysis, including the interaction term between increased late-stage CRC effect during the pandemic period and by each individual month, showed that the OR for late-stage CRC was highest in July during the pandemic, at 1.31 (95%CI: 1.13- 1.52) and also significantly higher in September at 1.16 (95%CI: 1.00- 1.35). CONCLUSION: We investigated the trend of CRC stage distribution during the COVID-19 pandemic using a nationwide hospital-claims database in Japan, and found that the proportion of early-stage cancers tended to decrease temporarily after the state of emergency declaration due to the COVID-19 pandemic, but the effect was only temporary.

Clinical Epidemiological Studies of Colorectal Cancer by Record Linkage of Cancer Registries and Biospecimen Data: A Systematic Review.

BACKGROUND: The incidence and prognosis of colorectal cancer are associated with lifestyle, family history, and genetic predisposition. Record linkage between cancer registries and biospecimen data would enable us to conduct clinical epidemiological studies on incidence or prognosis including genome information. In this study, we conducted a systematic review of clinical epidemiological studies of colorectal cancer using record linkage between cancer registries and biospecimen data and examined the possibilities for future use of this linkage. METHODS: We searched PubMed and Google Scholar for articles regarding cancer registries and biospecimen data use published before December 2021. Selected articles were summarized by cancer registry use, biospecimen use, exposure, outcome, informed consent, and participant numbers by study design and type of cancer registry. RESULTS: Of the 2,793 identified articles, 81 studies were included in this review. The most frequently used cancer registries and study design were site specific cancer registries and cohort studies. Most use of cancer registries was for patient selection in cohort studies and case selection in case-control studies. Most use of biospecimen data was for prognostic factors in cohort studies and risk factors in case-control studies. In site specific cancer registries for the examination of familial colorectal cancer, most use of biospecimen data is to examine genome mutation, expression, or deficiency. CONCLUSION: We suggest that record linkage between cancer registries and biospecimen data would enable the accurate capture of outcomes and detailed genome-environmental factors, and to conduct clinical epidemiological studies according to specific research questions and tailored study designs.

Transonic dislocation propagation in diamond.

The motion of line defects (dislocations) has been studied for more than 60 years, but the maximum speed at which they can move is unresolved. Recent models and atomistic simulations predict the existence of a limiting velocity of dislocation motion between the transonic and subsonic ranges at which the self-energy of dislocation diverges, though they do not deny the possibility of the transonic dislocations. We used femtosecond x-ray radiography to track ultrafast dislocation motion in shock-compressed single-crystal diamond. By visualizing stacking faults extending faster than the slowest sound wave speed of diamond, we show the evidence of partial dislocations at their leading edge moving transonically. Understanding the upper limit of dislocation mobility in crystals is essential to accurately model, predict, and control the mechanical properties of materials under extreme conditions.

Molecular epidemiological analyses of Clostridioides difficile isolates in a university hospital in Japan.

Background: We performed molecular epidemiological analyses of Clostridioides difficile isolates in a university hospital in Japan to reveal the risk of C. difficile infection. Methods: Cultured isolates from 919 stool samples from 869 patients obtained from July 2015 to August 2016 were subjected to toxin gene detection, ribotyping, multilocus sequence typing, antimicrobial susceptibility testing, and quantitative real-time polymerase chain reaction testing for C. difficile toxin gene expression. Results: Of the 919 stool samples from 869 patients, C. difficile was isolated from 153 samples (16.6%), of which 49 (32%) and 104 (68%) were from patients with and without C. difficile infection, respectively. Analyses showed genetic diversity, with ST8 and ST17 strains of healthcare-associated infections, some of which caused C. difficile infections. There was no significant difference in the transcription levels of C. difficile toxin genes between isolates from patients with and without C. difficile infection. Conclusions: Major Japanese clonal strains, ST8 and ST17, have been in the hospital environment for a long time and cause healthcare-associated C. difficile infections. The C. difficile toxin genes were transcribed in the isolates from both patients with and without C. difficile infection but were no significant relationship with the development of C. difficile infection.

Bilateral L5 pedicle fracture with L5-S1 spondylolisthesis after single-level L4-5 posterior lumbar interbody fusion: illustrative case.

BACKGROUND: Single-level posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF) is a commonly performed surgical procedure for L4-5 isthmic spondylolisthesis. Postoperative L5 pedicle fracture with rapidly progressive spondylolisthesis at L5-S1 segment after L4-5 PLIF/TLIF is quite rare, and the etiology remains unclear. This report describes this rare complication and proposes a possible etiology focusing on the lumbosacral sagittal imbalance characterized by an anteriorly shifted lumbar loading axis. OBSERVATIONS: The authors report a case complicated by L5 bilateral pedicle fractures and rapidly progressive spondylolisthesis at the L5-S1 segment very early after a single-level PLIF for L4-5 isthmic spondylolisthesis. Meyerding grade III anterolisthesis was observed at L5-S1 segment by 3 months after the initial surgery. Additional surgery was performed, and the fixation was extended to L4-ilium. Fracture healing was observed at 6 months postoperatively. LESSONS: This complication may have been caused by abnormal local shear forces on the posterior neural arch of L5 vertebra and L5-S1 intervertebral disc, which were triggered by the fusion surgery for L4 shear-type spondylolisthesis. L4 sagittal vertical axis is considered a reasonable parameter representing lumbosacral sagittal imbalance with an anteriorly shifted loading axis and may be a candidate for the predictive parameters of this rare complication.

Risk Factors for Cage Migration Following Lateral Lumbar Interbody Fusion Combined With Posterior Instrumentation: A Multicenter Retrospective Study of 983 Cases.

STUDY DESIGN: A multicenter retrospective study. OBJECTIVE: This study aimed to elucidate the incidence and risk factors of lateral cage migration (LCM) after lateral lumbar interbody fusion (LLIF) combined with posterior instrumentation. SUMMARY OF BACKGROUND DATA: LLIF has recently become a widely accepted procedure for the treatment of lumbar degenerative diseases. Although LLIF complications include vascular, nerve, and abdominal organ injuries, few studies have identified specific risk factors for LCM after LLIF. MATERIALS AND METHODS: Between January 2015 and December 2020, 983 patients with lumbar degenerative diseases or osteoporotic vertebral fractures underwent LLIF combined with posterior instrumentation. The fusion sites were located within the lumbosacral lesions. LCM was defined as a change of >3 mm in the movement of the radiopaque marker on radiographs. The patients were classified into LCM and non-LCM groups. Medical records and preoperative radiographs were also reviewed. The 1:5 nearest-neighbor propensity score matching technique was used to compare both groups, and radiologic parameters, including preoperative disk height (DH), preoperative sagittal disk angle, disk geometry, height variance (cage height minus DH), and endplate injury, were analyzed to identify the factors influencing LCM incidence. RESULTS: There were 16 patients (1.6%) with LCM (10 men and 6 women; mean age 70.1 yr). The Cochran-Armitage trend test showed a linear trend toward an increased rating of LCM with an increasing number of fused segments ( P =0.003), and LCM occurred at the terminal cage-inserted disk level in all patients in the LCM group. After propensity-matched analysis, we identified high DH ( P <0.001), large sagittal disk angle ( P =0.009), round-type disk ( P =0.008), and undersized cage selection ( P <0.001) as risk factors for LCM. CONCLUSION: We identified risk factors for LCM after LLIF combined with posterior instrumentation. To avoid this complication, it is important to select the appropriate cage sizes and enhance posterior fixation for at-risk patients.

Association of two-staged surgery with systemic perioperative complications in lateral lumbar interbody fusion for adult spinal deformity: a propensity score-weighted study.

PURPOSE: Adult spinal deformity (ASD) surgery carries a higher risk of perioperative systemic complications. However, evidence for the effect of planned two-staged surgery on the incidence of perioperative systemic complications is scarce. Here, we evaluated the effect of two-staged surgery on perioperative complications following ASD surgery using lateral lumbar interbody fusion (LLIF). METHODS: The study was conducted under a retrospective multi-center cohort design. Data on 293 consecutive ASD patients (107 in the two-staged group and 186 in the one-day group) receiving corrective surgery using LLIF between 2012 and 2021 were collected. Clinical outcomes included occurrence of perioperative systemic complications, reoperation, and intraoperative complications, operation time, intraoperative blood loss, transfusion, and length of hospital stay. The analysis was conducted using propensity score (PS)-stabilized inverse probability treatment weighting to adjust for confounding factors. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated in a PS-weighted cohort. RESULTS: In this cohort, 19 (18.4%) patients in the two-staged group and 43 (23.1%) patients in the one-day group experienced any systemic perioperative complication within 30 days following ASD surgery. In the PS-weighted cohort, compared with the patients undergoing one-day surgery, no association with the risk of systemic perioperative complications was seen in patients undergoing two-staged surgery (PS-weighted OR 0.78, 95% CI 0.37-1.63; p = 0.51). CONCLUSION: Our study suggested that two-staged surgery was not associated with risk for perioperative systemic complications following ASD surgery using LLIF.

The Prognostic Value of Preoperative Serum Markers and Risk Classification in Patients with Hepatocellular Carcinoma.

BACKGROUND: Complex hepatocellular carcinoma (HCC) prognostic biomarkers have been reported in various studies. We aimed to establish biomarkers that could predict prognosis, and formulate a simple classification using non-invasive preoperative blood test data. METHODS: We retrospectively identified 305 patients for a discovery cohort who had undergone HCC-related hepatectomy at four Japanese university hospitals between January 1, 2011 and December 31, 2013. Preoperative blood test parameter optimal cut-off values were determined using receiver operating characteristic curve analysis. Cox uni- and multivariate analyses were used to determine independent prognostic factors. Risk classifications were established using classification and regression tree (CART) analysis. Validation was performed with 267 patients from three other hospitals. RESULTS: In multivariate analysis, α-fetoprotein (AFP, p < 0.001), protein induced by vitamin K absence or antagonist-II (PIVKA-II, p = 0.006), and C-reactive protein (CRP, p < 0.001) were independent prognostic factors for overall survival (OS). AFP (p = 0.007), total bilirubin (p = 0.001), and CRP (p = 0.003) were independent recurrent risk factors for recurrence-free survival (RFS). CART analysis results formed OS (CRP, AFP, and albumin) and RFS (PIVKA-II, CRP, and total bilirubin) decision trees, based on machine learning using preoperative serum markers, with three risk classifications. Five-year OS (low risk, 80.0%; moderate risk, 56.3%; high risk, 25.2%; p < 0.001) and RFS (low risk, 43.4%; moderate risk, 30.8%; high risk, 16.6%; p < 0.001) risks differed significantly. These classifications also stratified OS and RFS risk in the validation cohort. CONCLUSION: Three simple risk classifications using preoperative non-invasive prognostic factors could predict prognosis.

Time to Treatment Initiation for Six Cancer Types: An Analysis of Data from a Nationwide Registry in Japan.

BACKGROUND: Delay in the time to treatment initiation (TTI) may adversely affect the survival of patients, but its current status in Japan is unknown. This study aims to describe the TTI for six cancer types: lung, breast, colorectal, stomach, head and neck (H&N), and cervical. Data for this study were derived from a nationwide registry in Japan. METHODS: This observational study employed the national database of hospital-based cancer registries (HBCRs) and health services utilization data. Using HBCR data, we identified all patients with cancer who started their cancer therapy at the same hospitals between January 1 and December 31, 2017. We calculated the TTI for each cancer type and treatment option, stratifying the results by age group and geographical region. RESULTS: The overall median TTI was 33 days, with shorter TTIs for colorectal and H&N cancers and chemotherapy. The TTI was the shortest for younger patients and the longest for the elderly, especially for lung cancer. When categorized by eight Japanese geographical regions, Tohoku and Kanto had the longest TTI. The result remained the same even after adjusting cancer type, treatment, age, and stage information. CONCLUSION: For colorectal and H&N cancers, in which a longer TTI is associated with a poorer prognosis, TTI was found to be particularly shorter. Although we could not discuss our results in light of the patient survival in this study, future research should explore the best balance between thorough evaluation before treatment and necessary time for that.

Short-term Outcomes of Laparoscopic and Open Distal Pancreatectomy Using Propensity Score Analysis: A Real-world Retrospective Cohort Study.

OBJECTIVE: This study aimed to compare the short-term outcomes between laparoscopic and open distal pancreatectomy for lesions of the distal pancreas from a real-world database. BACKGROUND: Reports on the benefits of laparoscopic distal pancreatectomy include 2 randomized controlled trials; however, large-scale, real-world data are scarce. METHODS: We analyzed the data of patients undergoing laparoscopic or open distal pancreatectomy for benign or malignant pancreatic tumors from April 2008 to May 2020 from a Japanese nationwide inpatient database. We performed propensity score analyses to compare the inhospital mortality, morbidity, readmission rate, reoperation rate, length of postoperative stay, and medical cost between the 2 groups. RESULTS: From 5502 eligible patients, we created a pseudopopulation of patients undergoing laparoscopic and open distal pancreatectomy using inverse probability of treatment weighting. Laparoscopic distal pancreatectomy was associated with lower inhospital mortality during the period of admission (0.0% vs 0.7%, P <0.001) and within 30 days (0.0% vs 0.2%, P =0.001), incidence of reoperation during the period of admission (0.7% vs 1.7%, P =0.018), postpancreatectomy hemorrhage (0.4% vs 2.0%, P <0.001), ileus (1.1% vs 2.8%, P =0.007), and shorter postoperative length of stay (17 vs 20 d, P <0.001). CONCLUSIONS: The propensity score analysis revealed that laparoscopic distal pancreatectomy was associated with better outcomes than open surgery in terms of inhospital mortality, reoperation rate, postoperative length of stay, and incidence of postoperative complications such as postpancreatectomy hemorrhage and ileus.

Preoperative Serum Markers and Risk Classification in Intrahepatic Cholangiocarcinoma: A Multicenter Retrospective Study.

Accurate risk stratification selects patients who are expected to benefit most from surgery. This retrospective study enrolled 225 Japanese patients with intrahepatic cholangiocellular carcinoma (ICC) who underwent hepatectomy between January 2009 and December 2020 and identified preoperative blood test biomarkers to formulate a classification system that predicted prognosis. The optimal cut-off values of blood test parameters were determined by ROC curve analysis, with Cox univariate and multivariate analyses identifying prognostic factors. Risk classifications were established using classification and regression tree (CART) analysis. CART analysis revealed decision trees for recurrence-free survival (RFS) and overall survival (OS) and created three risk classifications based on machine learning of preoperative serum markers. Five-year rates differed significantly (p < 0.001) between groups: 60.4% (low-risk), 22.8% (moderate-risk), and 4.1% (high-risk) for RFS and 69.2% (low-risk), 32.3% (moderate-risk), and 9.2% (high-risk) for OS. No difference in OS was observed between patients in the low-risk group with or without postoperative adjuvant chemotherapy, although OS improved in the moderate group and was prolonged significantly in the high-risk group receiving chemotherapy. Stratification of patients with ICC who underwent hepatectomy into three risk groups for RFS and OS identified preoperative prognostic factors that predicted prognosis and were easy to understand and apply clinically.

Reoperation for Misplaced Pedicle Screws: A Multicenter Retrospective Study.

STUDY DESIGN: A multicenter retrospective analysis. OBJECTIVE: This study aims to investigate reoperation of misplaced pedicle screws (MPSs) after posterior spinal fusion (PSF), focusing on neurological complications. SUMMARY OF BACKGROUND DATA: The management strategy for MPSs and the clinical results after reoperation are poorly defined. MATERIALS AND METHODS: Subjects were 10,754 patients (73,777 pedicle screws) who underwent PSF at 11 hospitals over 15 years. The total number of reoperations for MPS and patient clinical data were obtained from medical records at each hospital. RESULTS: The rate of reoperation for screw misplacement per screw was 0.17%. A total of 69 patients (mean age, 67.4±16.5 yr) underwent reoperation because of 82 MPS. Reasons for reoperation were neurological symptoms (58 patients), contact with vessels (5), suboptimal bone purchase (4), and misplacement recognized during operation (2). Neurological symptoms were the major reason for reoperation in cervical (5/5 screws, 100%) and lumbo-sacral (60/67 screws, 89.6%) regions. Contact with vessels was the major reason for reoperation in the thoracic spine (6/10 screws, 60.0%). We further evaluated 60 MPSs in the lumbo-sacrum necessitating reoperation because of neurological symptoms. The majority of MPSs necessitating reoperation were placed in the lower lumbar spine (43/60 screws, 71.7%). The mean pedicle breach tended to be larger in the incomplete recovery group than in the complete recovery group (6.8±2.4 vs . 5.9±2.2 mm, P =0.146), and the cutoff value resulting in incomplete resolution was 5.0 mm. Multivariate analysis revealed that medial-caudal breaches ( vs . medial breach, odds ratio: 25.8, 95% confidence interval: 2.58-258, P =0.0057) and sensory and motor disturbances ( vs . sensory only, odds ratio: 8.57, 95% confidence interval: 1.30-56.6, P =0.026) were significant factors for incomplete resolution of neurological symptoms. CONCLUSIONS: After reoperation, 70.1% of the patients achieved complete resolution of neurological symptoms. Factors associated with residual neurological symptoms included sensory and motor disturbance, medial-caudal breach, and larger pedicle breach (>5 mm).