Patients with a large ossification of the posterior longitudinal ligament have a higher incidence of arteriosclerosis in the carotid artery.

PURPOSE: This study aimed to investigate the impact of the severity of cervical ossification of the posterior longitudinal ligament (OPLL) on the incidence of arteriosclerosis in the carotid artery. METHODS: Patients with OPLL-induced cervical myelopathy were prospectively enrolled. The study involved analyzing patient characteristics, blood samples, computed tomography scans of the spine, and intima-media thickness (IMT) measurements of the common carotid artery. Patients were divided into two groups based on the size of the cervical OPLL to compare demographic data, comorbidities, and the presence of thickening of the carotid intima-media (max IMT ≥ 1.1 mm). RESULTS: The study included 96 patients (mean age: 63.5 years; mean body mass index: 26.9 kg/m2; 71.8% male; 35.4% with diabetes mellitus). The mean maximum anteroposterior (AP) diameter of the OPLL was 4.9 mm, with a mean occupancy ratio of 43%. The mean maximum IMT was 1.23 mm. Arteriosclerosis of the carotid artery was diagnosed in 62.5% of the patients. On comparing the two groups based on OPLL size, the group with larger OPLL (≥ 5 mm) had a higher BMI and a greater prevalence of carotid intima-media thickening. This significant difference in the prevalence of carotid intima-media thickening persisted even after adjusting for patient backgrounds using propensity score matching. CONCLUSIONS: Patients with a larger cervical OPLL showed a higher frequency of intima-media thickening in the carotid artery.

Trends in inpatient orthopedic surgery during the COVID-19 pandemic in Japan: a nationwide data study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has resulted in substantial morbidity and mortality globally. The National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) covers 99.9% of health insurance claim receipts by general practitioners. The purpose of this study is to investigate the nationwide number of inpatient orthopedic surgeries in Japan during the effect of state of emergency (SoE) due to COVID-19. METHOD: The NDB has been publicly available since 2014. We retrospectively reviewed the NDB from April 2019 to March 2022. We gathered the monthly number of all inpatient orthopedic surgeries. We also classified orthopedic surgeries into the following 11 categories by using K-codes, Japanese original surgery classification: fracture, arthroplasty, spine, arthroscopy, hardware removal, hand, infection/amputation, ligament/tendon, tumor, joint, and others. By using the average number from April to December 2019 as the reference period, we investigated the increase or decrease orthopedic surgeries during the pandemic period. RESULTS: The NDB showed that the average number of total inpatient orthopedic surgeries during the reference period was 115,343 per month. In May 2020, monthly inpatient orthopedic surgeries decreased by 29.6% to 81,169 surgeries, accounting for 70.3% of the reference period. The second SoE in 2021 saw no change, while the third and fourth SoEs showed slight decreases compared to the reference period. Hardware removal and tumor surgeries in May 2020 decreased to 45.3% and 45.5%, respectively, while fracture surgeries had relatively small decreases. CONCLUSION: According to NDB, approximately 1.3 million orthopedic inpatient surgeries were performed or claimed in a year in Japan. In May 2020, the first SoE period of the COVID-19 pandemic, the number of inpatient orthopedic surgeries in Japan decreased by 30%. Meanwhile, the decrease was relatively small during the SoE periods in 2021.

Estimated number of spine surgeries and related deaths in Japan from 2014 to 2020.

BACKGROUND: The total number of spine surgeries per year and their related deaths in Japan has not been adequately estimated in the literature. METHODS: We retrospectively reviewed the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) between April 2014 to March 2021, which covers 99.9 % of health insurance claim receipts by general practitioners. The annual number of surgeries was counted using K codes, a procedure classification unique to Japan, and classified into the following six categories; percutaneous vertebroplasty, endoscopic surgery, open discectomy, laminoplasty/laminectomy, instrumentation surgery, and others. The data distribution was also summarized by sex and age. Additionally, by reviewing DPC database-related papers for evaluation of the mortality rate after spine surgery in Japan, the number of spine surgery-related deaths was calculated. RESULTS: The NDB showed that the number of spine surgeries analyzed in this study increased from 170,081 in 2014 to 193,903 in 2019, with a slight decrease in 2020. The ratio of instrumentation surgery increased from 33.0 % in 2014 to 37.9 % in 2020. The rate of patients aged 75 or older increased 31.6 % to 39.6 %. Combining these findings with DPC data showing a mortality rate of 0.1 % to 0.4 % revealed that the estimated number of deaths related to spine surgery in Japan ranged from 200 to 800 per year. CONCLUSIONS: Approximately 200,000 spine surgeries and 200 to 800 spine surgery-related inpatient deaths were estimated to have occurred in Japan around 2020.

Regulation of osteoarthritis development by ADAM17/Tace in articular cartilage.

INTRODUCTION: A disintegrin and metalloproteinase 17 (Adam17), also known as TNFα-converting enzyme (Tace), is a membrane-anchored protein involved in shedding of TNF, IL-6 receptor, ligands of epidermal growth factor receptor (EGFR), and Notch receptor. This study aimed to examine the role of Adam17 in adult articular cartilage and osteoarthritis (OA) pathophysiology. MATERIALS AND METHODS: Adam17 expression was examined in mouse knee joints during OA development. We analyzed OA development in tamoxifen-inducible chondrocyte-specific Adam17 knockout mice of a resection of the medial meniscus and medial collateral ligament (medial) model, destabilization of the medial meniscus (DMM) model, and aging model. We analyzed downstream pathways by in vitro experiments, and further performed intra-articular administration of an Adam17 inhibitor TAPI-0 for surgically induced mouse OA. RESULTS: Adam17 expression in mouse articular cartilage was increased by OA progression. In all models, Adam17 knockout mice showed ameliorated progression of articular cartilage degradation. Adam17 knockout decreased matrix metallopeptidase 13 (Mmp13) expression in both in vivo and in vitro experiments, whereas Adam17 activation by phorbol-12-myristate-13-acetate (PMA) increased Mmp13 and decreased aggrecan in mouse primary chondrocytes. Adam17 activation enhanced release of soluble TNF and transforming growth factor alpha, a representative EGF ligand, from mouse primary chondrocytes, while it did not change release of soluble IL-6 receptor or nuclear translocation of Notch1 intercellular domain. Intra-articular administration of the Adam17 inhibitor ameliorated OA progression. CONCLUSIONS: This study demonstrates regulation of OA development by Adam17, involvement of EGFR and TNF pathways, and the possibility of Adam17 as a therapeutic target for OA.

Does T1 slope minus cervical lordosis mismatch affect surgical outcomes of cervical laminoplasty in the absence of preoperative severe kyphosis?

BACKGROUND: The impact of the T1 slope minus cervical lordosis (T1S-CL) on surgical outcomes in patients with degenerative cervical myelopathy undergoing laminoplasty (LP) remain uncertain. METHODS: One hundred patients who underwent cervical LP were retrospectively reviewed. Radiographic measurements included C2-C7 lordosis (CL), T1 slope (T1S), and C2-C7 sagittal vertical axis (SVA). Additionally, pain numeric rating scale, neck disability index (NDI), 12-Item Short-Form Health Survey, Euro QOL 5 dimensions (EQ5D), and Japanese Orthopedic Association score were investigated. According to past reports, T1S-CL > 20° was defined as mismatched. Then, based on T1S-CL mismatching, patients were divided into 2 groups. RESULTS: This research understudied 67 males and 33 females with a mean age of 67 y. Preoperatively, only eight patients showed a T1S-CL mismatch. While the C2-7 Cobb angles did not change significantly after surgery, the T1 slope (T1S) angle increased, increasing the T1S-CL as a result. As we compared the clinical outcomes based on the preoperative T1S-CL mismatching, there were no significant differences between the two groups. On the other hand, the number of patients in the mismatched group increased to 21 patients postoperatively. As we compared clinical outcomes based on the postoperative T1S-CL mismatching, the postoperative NDI score and preop/postop EQ5D score were significantly worse in the mismatch group. CONCLUSIONS: Although cervical LP showed inferior outcomes in patients with postoperative T1S-CL mismatch even in the absence of severe preoperative kyphosis (> 10°), preoperative T1S-CL mismatch was not adversely prognostic.

Necrotizing fasciitis of the extremities in high and low Charlson Comorbidity Index: A multi-center retrospective cohort study.

BACKGROUND: Necrotizing fasciitis (NF) is a life-threatening and acute progressive soft tissue infection and needs early surgical intervention, that is, debridement or amputation. Surgical strategy or prognosis is influenced by the speed of progression and patients' general condition, which can be calculated by the Charlson Comorbidity Index (CCI). The purpose of this study was to investigate the association between the CCI scores and prognosis of patients with NF of the upper/lower extremities. METHODS: In the retrospective cohort study, we analyzed patients with NF of the upper/lower extremities who were determined to undergo surgery by orthopedic surgeons at four tertiary hospitals between August 2003 and April 2016. We divided the patients into two groups, Group L (low CCI scores of 0-2) and Group H (high CCI scores of ≥3). The primary event of this study was defined as death or amputation. Mortality cases were included when amputation was informed with documented certification but patients died while waiting for surgery. We compared the patients' background, laboratory data on admission, the laboratory risk indicator for necrotizing fasciitis (LRINEC) score, and primary outcome between the two groups. RESULTS: Of the 56 patients, 28 patients were classified into Group L and the other 28 patients into Group H. The data in this study showed that patients in Group H had lower white blood cell counts and hemoglobin and higher creatinine than Group L, but there was no difference in LRINEC scores between the two groups. Streptococcus pyogenes was the most common infectious agent in Group L (54%) but not in Group H (11%). Poorer outcome was observed in Group H compared with Group L (4 mortality and 16 amputation vs. no mortality and 9 amputation, P = 0.007). CONCLUSIONS: Laboratory data and causative microorganisms were different between high CCI and low CCI patients with NF. High CCI scores were associated with limb amputation or death caused by NF of the upper/lower extremities; whereas, low CCI scores were more likely associated with S. pyogenes monoinfection.

Minimum clinically important change for outcome scores among patients aged 75 or over undergoing lumbar spine surgery.

PURPOSE: To elucidate the minimum clinically important change (MCIC) of the physical component summary (PCS) of the Short Form-12, Oswestry Disability Index (ODI), EuroQOL-5 dimensions (EQ-5D), and the Core Outcome Measures Index (COMI) in patients aged ≥ 75 years undergoing lumbar spine surgery. METHODS: We retrospectively reviewed patients aged ≥ 75 years with degenerative lumbar spine disease who underwent lumbar spine decompression or fusion surgery within three levels between April 2017 and June 2018. We also evaluated patients aged < 75 years in the same period as reference. We evaluated the baseline and postoperative PCS, ODI, EQ-5D, and COMI scores. Patients were asked to answer an anchor question regarding health transition for MCICs using the anchor-based method. RESULTS: A total of 247 patients aged ≥ 75 years and 398 patients aged < 75 years were included for analysis. Of patients aged ≥ 75 years, 83.4% showed at least "somewhat improved" outcomes, while 91.0% of patients aged < 75 years reported this outcome. PCS change score was not adequately correlated to health transition in patients aged ≥ 75 years. Receiver operating characteristic curve analyses revealed MCICs of 17.8 for ODI, 0.18 for EQ-5D, and 1.6 for COMI in patients aged ≥ 75 years, and 12.7 for ODI, 0.19 for EQ-5D, and 2.3 for COMI in patients aged < 75 years. CONCLUSION: In patients aged ≥ 75 years, PCS may not be feasible for evaluation of health transition. The MCIC value for ODI score was higher and that for EQ-5D/COMI score was lower in patients aged ≥ 75 years, compared with those in patients aged < 75 years.

Validity of the Japanese core outcome measures index (COMI)-neck for cervical spine surgery: a prospective cohort study.

PURPOSE: To investigate the psychometric properties of the Japanese version of the Core Outcome Measures Index-Neck (COMI-Neck) in patients undergoing cervical spine surgery. METHODS: A total of 177 patients undergoing cervical spine surgery for spinal disorders from April to December 2017 were enrolled. Patient-reported outcomes (PROs) included EuroQOL, Neck Disability Index, and treatment satisfaction. To address whether the questionnaire's scores relate to other outcomes based on a predefined hypothesis, the correlations between the COMI-Neck and the other PROs were measured (Spearman's rank correlation coefficients). The minimum clinically important difference (MCID) of the COMI summary score was calculated using the receiver operating characteristic (ROC) curve with a 7-point Likert scale of satisfaction with the treatment results. To assess reproducibility, another group of 59 volunteers with chronic neck pain were asked to reply to the COMI-Neck twice with an interval of 7-14 days. RESULTS: The COMI summary score showed no floor or ceiling effects preoperatively or postoperatively. Each of the COMI domains and the COMI summary score correlated to the hypothesized extent with the scores of the reference questionnaires (ρ = 0.40-0.79). According to the ROC curve with satisfaction (including "very satisfied" and "satisfied"), the area under the curve and MCID of the COMI summary score were 0.78 and 2.1. The intraclass correlation coefficient and the minimum detectable change (MDC 95%) of the COMI summary score were 0.97 and 0.77. CONCLUSION: The Japanese version of the COMI-Neck is valid and reliable for Japanese-speaking patients with cervical spinal disorders.

Risk factors for worsening sexual function after lumbar spine surgery and characteristics of non-responders to the questionnaire of sex life.

PURPOSE: To precisely assess the Oswestry Disability Questionnaire (ODQ) and its total score (Oswestry Disability Index: ODI) and reveal characteristics of non-responders of the 8th item of ODQ (ODI-8) relating to sexual function. Furthermore, we evaluated risk factors for aggravation of postoperative sexual function. METHODS: We enrolled patients undergoing lumbar spine surgery at eight hospitals between April 2017 and November 2018. Patients' background data and operative factors were collected. We also assessed pain or dysesthesia (lower back, buttock, leg, and plantar area) on a numerical rating scale, EuroQol 5 Dimension, core outcome measures index back, and ODI before and 1 year after surgery. Factor analysis was conducted for the ODQ. Non-responders of the ODI-8 were compared with full-responders using propensity score matching. Risk factors for worsening ODI-8 were evaluated by multivariate logistic regression analysis. RESULTS: Of the 2,610 patients enrolled, 601 (23.0%) answered all but the ODI-8 item; these patients were likely to show better preoperative clinical symptoms than full-responders, even after adjusting for age and gender using propensity scores. Age, spinal deformity, and the American Society of Anesthesiologists physical status (ASA-PS) 3/4 were significant risk factors for postoperative aggravation of the ODI-8. Factor analysis revealed that the ODQ was composed of dynamic and static activities; the ODI-8 was considered a dynamic activity. CONCLUSION: Almost a fourth of the patients skipped the ODI-8. Age, the presence of spinal deformity, and worse ASA-PS were found to be risk factors for postoperative aggravation of sexual function. LEVEL OF EVIDENCE I: Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Validity of the Japanese Core Outcome Measures Index (COMI)-Back for thoracic and lumbar spine surgery: a prospective cohort study.

PURPOSE: To investigate the psychometric properties of the Japanese version of the Core Outcome Measures Index-Back (COMI-Back), only recently published according to the established linguistic and cultural conversion guidelines, in patients undergoing spine surgery. METHODS: We recruited 145 patients who underwent thoracic or lumbar spine surgery in one of the five specific tertiary care institutions. They were asked to complete a booklet questionnaire (the COMI-Back, the Numerical Rating Scale for pain, the Short Form-12, Euro-QOL-5 dimensions, and Oswestry Disability Index) at baseline and 12 months postoperatively to investigate floor/ceiling effect, construct validity, and postoperative responsiveness. The patients were also asked to answer an anchor question (Global Treatment Outcome) to analyze the minimum clinically important difference (MCID) by receiver operating characteristics curves. Of the 145 patients, 112 completed the study. Another group of 59 volunteers with chronic symptoms completed the questionnaire twice within a 7-14-day interval for the test-retest reproducibility. RESULTS: The COMI summary score displayed no notable floor or ceiling effects. Except for symptom-specific well-being, the individual COMI domains and the COMI summary score correlated as expected with the scores of the chosen reference measures (ρ = 0.4-0.8). A similar trend was observed between the pre-/postoperative changes in the COMI score and those in the reference measures. The MCID for the COMI summary score was 2.5. The intraclass correlation coefficient and minimum detectable change (MDC95%) were 0.93 and 1.26, respectively. CONCLUSION: The Japanese COMI-Back was a reliable and responsive questionnaire in our Japanese patients undergoing thoracic/lumbar spine surgery. These slides can be retrieved under Electronic Supplementary Material.

A sliding scale to predict postoperative complications undergoing posterior spine surgery.

BACKGROUND: There is a lack of consensus of operative time (OT) and estimated blood loss (EBL) for elderly patients based on the predicted risk of complications after posterior spine surgery. The purpose of this study was to evaluate the effect of age, OT, and EBL on the postoperative complication risk and to develop a simple sliding scale. METHODS: We explored prospectively collected data of consecutive patients who underwent posterior spine surgery in seven tertiary referral hospitals from November 2013 to May 2016. Age (<70, 70-74, 75-79, 80-84, ≥85 years), OT (<2, 2-<3, 3-<4, 4-<5, ≥5 h), and EBL (<500, 500-<1000, 1000-<1500, 1500-<2000, ≥2000 ml) were categorized ranging from 1 (lowest) to 5 (highest). The association between the crude cumulative categories' number and the incidence of complications was analyzed. We further evaluated the association by re-categorizing the cumulative number into three groups (3-4, 5-10, ≥11). RESULTS: Total of 2416 patients (median age: 70 years old) were enrolled and major complications were observed in 75 (3.1%) patients. Age, OT, and EBL showed similar odds ratio (1.18-1.19) as each category increased. The cumulative categories' number fitted the estimate complication risk (Hosmer-Lemeshow P = 0.87), and statistically significant trend was observed between predicted and actual complication rates (Cochran-Armitage test, P < 0.001). When cumulative categories' numbers were stratified into three groups, significant increasing trend of risk were observed (Mantel-Haenszel P < 0.001). Based on the categorical numbers, we proposed a simple sliding scale. CONCLUSION: Our data indicated that the risk of postoperative complication was associated with cumulative score based on increased age, OT, and EBL. A simple sliding scale was developed based on these factors, which may be useful to predict complication risk after posterior spine surgery.

Non-inferior comparative study comparing one or two day antimicrobial prophylaxis after clean orthopaedic surgery (NOCOTA study): a study protocol for a cluster pseudo-randomized controlled trial comparing duration of antibiotic prophylaxis.

BACKGROUND: Antimicrobial prophylaxis (AMP) is one of the most important measures for preventing surgical site infections (SSIs); however, controversies remain regarding its adequate duration. Although the World Health Organization and the Center for Disease Control and Prevention do not recommend additional AMP after closure, the American Society of Health-System Pharmacists and the Musculoskeletal Infection Society permit the use of postoperative AMP, but recommend discontinuation within 24 h. Similarly, the Japanese Society of Chemotherapy and the Japan Society for Surgical Infection also permit AMP within 24-48 h after various orthopaedic procedures. In these guidelines, recommendations regarding AMP duration were weak due to a relative lack of evidence, and currently, there is no high-quality evidence comparing AMP use within 24 h versus 24-48 h regarding orthopaedic procedures. Urinary tract infection (UTI) and respiratory tract infection (RTI) are also important health care-associated infections (HAIs) faced after surgery. Although AMP duration may affect these HAIs, its effects have not been well evaluated. METHODS: We have organized a multicenter, prospective, cluster pseudo-randomized controlled trial to examine the non-inferiority of shorter AMP duration (within 24 h) against longer duration (24-48 h) in preventing postoperative HAIs. Participating facilities will be divided into two groups. In Group 24, AMP will be discontinued within 24 h after surgery. In Group 48, AMP will be discontinued within 24-48 h after surgery. The group allocation will be switched every 2 months until the targeted recruitment (500 participants per group) is met. The primary outcome will be the cumulative incidence of all HAIs (SSI, UTI, RTI, and other infectious diseases), which require antibiotic therapies within 30 days after surgery. In addition to mortality and cardiovascular events, prolonged hospitalization (> 30 days) and the rate of antibiotic resistance rate of SSI pathogens will also be evaluated. Outcomes will be evaluated within 30-180 days after surgery in person by the surgeon, by mail, or by telephone survey. Data will be analyzed by a statistician not engaged in data collection. DISCUSSION: This study may provide valuable information for developing future recommendations for adequate AMP duration after clean orthopaedic surgery. TRIAL REGISTRATION: UMIN000030929, registered January 22, 2018.

Adaptation and limitation of anterior column reconstruction for pyogenic spondylitis in lower thoracic and lumbar spine.

BACKGROUND: Surgical strategy for pyogenic spondylitis is controversial when vertebral body erosion is severe. Radical debridement and anterior column reconstruction is indicated for the purpose of early ambulatory to prevent secondary complication for long bed rest. However, such aggressive debridement and risk of perioperative complications are trade-off. The purpose of this study was to evaluate the risk factor of poor prognosis after anterior column debridement and reconstruction for pyogenic spondylitis in lower thoracic and lumbar spine. METHODS: We performed a retrospective review of 40 patients diagnosed with pyogenic spondylitis in lower thoracic and lumbar spine who were introduced to our institution due to losing ambulatory ability and underwent anterior column debridement and reconstruction between January 2008 and May 2016. After the patient population was split into a regaining ambulatory group (Group A; n = 23) and a poor prognosis group (Group P; n = 17), we used Fisher exact tests and t-tests as appropriate for univariate analyses to compare patient characteristics and outcomes between the 2 groups. RESULTS: Univariate analysis showed that the significant variables were massive bleeding (>2000 ml) (P < 0.01), Charlson Comorbidity Index ≥3 (P = 0.01), and two-stage surgery needed (P = 0.04). Logistic regression analysis showed that the factors associated with poor prognosis were massive bleeding (Odds Ratio 11.9; 95% confidence interval 1.8 to 119.7; P = 0.04). CONCLUSIONS: Massive bleeding was associated with poor prognosis after debridement followed by anterior column reconstruction for pyogenic spondylitis in lower thoracic and lumbar spine.

Acute complete paraplegia of 8-year-old girl caused by spinal cord infarction following minor trauma complicated with longitudinal signal change of spinal cord.

INTRODUCTION: Spinal cord infarction followed by minor trauma in pediatric patients is rare and causes serious paralysis. Fibrocartilaginous embolism (FCE) is a possible diagnosis and there have been no consecutive magnetic resonance imaging (MRI) reports. Here, we report a case of an acute complete paraplegia with spinal cord infarction and longitudinal spinal cord signal change following minor trauma in an 8-year-old girl. CASE DESCRIPTION: An 8-year-old girl presented to our hospital emergency services with total paraplegia 2 h after she hit her back and neck after doing a handstand and falling down. She completely lost pain, temperature sensation, and a sense of vibration below her bilateral anterior thighs. Four hours later on MRI, the T2-weighted sequence showed no spinal cord compression or signal change in vertebral bodies. The patient was treated with rehabilitation after complete bed rest. A week after the trauma, the T2-weighted sequence indicated longitudinal extension of the lesion between T11 and C6 vertebral level with ring-shaped signal change. In addition, the diffusion-weighted MRI showed increased signal below C6 vertebral level. Two weeks after the trauma, we performed the T2 star sequence images, which showed minor bleeding at T11 vertebral area and spinal cord edema below C6. Four weeks after the trauma, MRI showed minor lesion at C6 vertebral level, but spinal cord atrophy was observed at T11 vertebral level without disc signal change. Thirteen weeks after the trauma, her cervical spinal cord became almost intact and severe atrophy of the spinal cord at T11 vertebral level. At 1 year following her injury, complete paraplegia remained with sensory loss below T11 level. CONCLUSION: Her clinical presentation, lack of evidence for other plausible diagnosis, and consecutive MRI findings made FCE at T11 vertebral level with pencil-shaped softening the most likely diagnosis. In addition, consecutive cervical MRI indicated minor cervical spinal cord injury. This Grand Round case highlights the consecutive MRI in a case with double spinal cord lesion with longitudinal spinal cord signal change.

Early versus delayed reduction of cervical spine dislocation with complete motor paralysis: a multicenter study.

PURPOSE: Reduction of cervical facet dislocation should be performed as soon as possible to depressurize neuron cells although some randomized control studies defined early reduction as over 24 h after trauma. The purpose of this study was to define the actual time limit for early reduction in patients with complete motor paralysis. METHODS: Cervical spine dislocation patients with complete motor paralysis admitted between April 2007 and December 2014 were analyzed as retrospective cohort study. We separated the patients into three groups according to the number of hours lapsed between the trauma and reduction, within 4 h (very early group), >4-6 h (early group), and >6 h (delayed group). We compared the neurological outcomes, patient injury patterns, the arrival time at the hospital, and the injury severity score (ISS). RESULTS: Of 30 patients who enrolled, 8 (27%) were recovered to American Spinal Injury Association Impairment Scale Grades C-E. The delayed group had poorer neurological outcomes than the very early group and early group, although no significant differences were noted in the recovery rate between the very early group and early groups. The injury pattern, arrival time, and ISS were not found to be associated with the neurological outcome. CONCLUSION: Our data suggest that early (<6 h) reduction of cervical spine dislocation is associated with favorable neurological outcome as compared with those performed after 6 h.

Direct Damage to a Vertebral Artery Better Predicts a Vertebral Artery Injury than Elongation in Cervical Spine Dislocation.

Cervical spine dislocation and fracture of a transverse process are isolated risk factors for vertebral artery injuries (VAIs), which can cause a life-threatening ischemic stroke. Since in vivo experiments are not possible, it has not been unclear whether damage to or extension of vertebral arteries is more predictive of a VAI. To identify the imaging characteristics associated with VAI, we analyzed 36 vertebral arteries from 22 cervical spine dislocation patients who underwent computed tomography angiography (Aug. 2008-Dec. 2014). We evaluated (1) the posttraumatic elongation of the vertebral artery and (2) the presence of fracture involving the transverse foramen. VAI was found in 20 (56%) of the 36 vertebral arteries. The rate of residual shift (vertebral artery elongation) was not markedly different between the VAI and no-VAI groups. However, the rate of >1 mm displacement into the foramen and that of fracture with gross displacement (≥2 mm) differed significantly between the groups. We found that greater displacement of fractured transverse processes with cervical spine dislocation was a risk factor for VAI. These results suggest that direct damage to the vertebral arteries by transverse process fragments is more likely to predict a VAI compared to elongation, even in cervical spine dislocation.

A Diagnostic Algorithm for Eosinophilic Granulomatosis with Polyangiitis Initially Diagnosed as Lumbar Disc Hernia or Lumbar Spinal Stenosis: Personal Experience and Review of the Literature.

Eosinophilic granulomatosis with polyangiitis (EGPA, Churg-Strauss syndrome) is a rare systemic vasculitis and is difficult to diagnose. EGPA has a number of symptoms including peripheral dysesthesia caused by mononeuropathy multiplex, which is similar to radiculopathy due to lumbar disc hernia or lumbar spinal stenosis. Therefore, EGPA patients with mononeuropathy multiplex often visit orthopedic clinics, but orthopedic doctors and spine neurosurgeons have limited experience in diagnosing EGPA because of its rarity. We report a consecutive series of patients who were initially diagnosed as having lumbar disc hernia or lumbar spinal stenosis by at least 2 medical institutions from March 2006 to April 2013 but whose final diagnosis was EGPA. All patients had past histories of asthma or eosinophilic pneumonia, and four out of five had peripheral edema. Laboratory data showed abnormally increased eosinophil counts, and nerve conduction studies of all patients revealed axonal damage patterns. All patients recovered from paralysis to a functional level after high-dose steroid treatment. We shortened the duration of diagnosis from 49 days to one day by adopting a diagnostic algorithm after experiencing the first case.

Risk Factors for Medial Breach During Robotic-Assisted Cortical Bone Trajectory Screw Insertion.

OBJECTIVE: We describe the incidence of, and identify the risk factors for, a medial breach of the pedicle wall during robotic-assisted cortical bone trajectory (RA-CBT) screw insertion. METHODS: We analyzed a consecutive series of adult patients who underwent RA-CBT screw placement from January 2019 to July 2022. To assess the pedicle wall medial breach, postoperative computed tomography (CT) images were analyzed. Patient demographic data and screw data were compared between patients with and without a medial breach. The Hounsfield units (HUs) on the L1 midvertebral axial CT scan was used to evaluate bone quality. RESULTS: Of 784 CBT screws in 145 patients, 30 (3.8%) had a medial breach in 23 patients (15.9%). One screw was grade 2, and the others were grade 1. Patients with a medial breach had a lower HU value compared with the patients without a medial breach (123.3 vs. 150.5; P = 0.027). A medial breach was more common in the right than left side (5.5% vs. 2.0%; P = 0.014). More than one half of the screws with a medial breach were found in the upper instrumented vertebra (UIV) compared with the middle construct or lowest instrumented vertebra (6.7% vs. 1.3% vs. 2.7%; P = 0.003). Binary logistic regression showed that low HU values, right-sided screw placement, and UIV were associated with a medial breach. No patients returned to the operating room for screw malposition. No differences were found in the clinical outcomes between patients with and without a medial breach. CONCLUSIONS: The incidence of pedicle wall medial breach was 3.8% of RA-CBT screws in the postoperative CT images. A low HU value measured in the L1 axial image, right-sided screw placement, and UIV were associated with an increased risk of medial breach for RA-CBT screw placement.

Normative Bone Mineral Density Measured on Computed Tomography Scans in Children and Adolescents.

STUDY DESIGN: Retrospective chart review. OBJECTIVE: To provide reference values for Hounsfield unit (HU) measured on computed tomography (CT) scans of children and adolescents. SUMMARY OF BACKGROUND DATA: Spine surgeons increasingly use HU on spine CT as a measure of bone mineral density (BMD). This has not been described in children and adolescents. PATIENTS AND METHODS: Pediatric patients who had a spine CT between 2012 and 2022 were identified. Patients who had more than 1 comorbidity or were syndromic were excluded. Using the bone window, 3 axial images (cephalad, middle, and caudal) of each vertebra were selected. In each axial view, the HU was measured using a "region of interest" (ROI) that included the total cancellous bone area and an ROI excluding the radiolucency present in the posterior vertebral body ("total" vs . "limited"). HU values were compared between total and limited areas and between the axial images at the cephalad, middle, and caudal levels. Each age category data were estimated and stratified. RESULTS: A total of 144 patients (79 females and 65 males) from 2 to 17 years old were included. Mean limited HU was consistently lower than total HU across all images and lumbar levels except for L1. Limited HU taken mid-vertebral body was also consistently lower than those taken cephalad or caudad. Mean limited HU across all ages including all levels was 227 ± 50 (range: 109-357). Stratifying by age showed a gradual decrease in BMD from age 2 to 10 followed by an increase. CONCLUSIONS: This is the first study to measure HU on lumbar CTs in children and adolescents. The technique of measuring BMD in adults should be modified in children by using an ROI that excludes the rarefaction present in the posterior vertebral body. Further studies are needed to evaluate the age-dependent changes in BMD seen in this study.

Comparison of No Tap (two-step) and tapping robotic assisted cortical bone trajectory screw insertion.

Workflow for cortical bone trajectory (CBT) screws includes tapping line-to-line or under tapping by 1 mm. We describe a non-tapping, two-step workflow for CBT screw placement, and compare the safety profile and time savings to the Tap (three-step) workflow. Patients undergoing robotic assisted 1-3 level posterior fusion with CBT screws for degenerative conditions were identified and separated into either a No-Tap or Tap workflow. Number of total screws, screw-related complications, estimated blood loss, operative time, robotic time, and return to the operating room were collected and analyzed. There were 91 cases (458 screws) in the No-Tap and 88 cases (466 screws) in the Tap groups, with no difference in demographics, revision status, ASA grade, approach, number of levels fused or diagnosis between cohorts. Total robotic time was lower in the No-Tap (26.7 min) versus the Tap group (30.3 min, p = 0.053). There was no difference in the number of malpositioned screws identified intraoperatively (10 vs 6, p = 0.427), screws converted to freehand (3 vs 3, p = 0.699), or screws abandoned (3 vs 2, p = 1.000). No pedicle/pars fracture or fixation failure was seen in the No-Tap cohort and one in the Tap cohort (p = 1.00). No patients in either cohort were returned to OR for malpositioned screws. This study showed that the No-Tap screw insertion workflow for robot-assisted CBT reduces robotic time without increasing complications.