Actions of remimazolam on inhibitory transmission of rat spinal dorsal horn neurons.

Remimazolam is an ultra-short benzodiazepine that acts on the benzodiazepine site of γ-aminobutyric acid (GABA) receptors in the brain and induces sedation. Although GABA receptors are found localized in the spinal dorsal horn, no previous studies have reported the analgesic effects or investigated the cellular mechanisms of remimazolam on the spinal dorsal horn. Behavioral measures, immunohistochemistry, and in vitro whole-cell patch-clamp recordings of dorsal horn neurons were used to assess synaptic transmission. Intrathecal injection of remimazolam induced behavioral analgesia in inflammatory pain-induced mechanical allodynia (six rats/dose; p < 0.05). Immunohistochemical staining revealed that remimazolam suppressed spinal phosphorylated extracellular signal-regulated kinase activation (five rats/group, p < 0.05). In vitro whole-cell patch-clamp analysis demonstrated that remimazolam increased the frequency of GABAergic miniature inhibitory post-synaptic currents, prolonged the decay time (six rats; p < 0.05), and enhanced GABA currents induced by exogenous GABA (seven rats; p < 0.01). However, remimazolam did not affect miniature excitatory post-synaptic currents or amplitude of monosynaptic excitatory post-synaptic currents evoked by Aδ- and C-fiber stimulation (seven rats; p > 0.05). This study suggests that remimazolam induces analgesia by enhancing GABAergic inhibitory transmission in the spinal dorsal horn, suggesting its potential utility as a spinal analgesic for inflammatory pain.

Delayed paraparesis after posterior spinal fusion for congenital scoliosis: a case report.

INTRODUCTION: Although multimodal intraoperative neuromonitoring (IONM), which has high sensitivity and specificity, is typically performed during spinal deformity surgery, neurological status may deteriorate with delay after surgical maneuvers. Here, we report a rare case of delayed postoperative neurological deficit (DPND) that was not detected by IONM during posterior spinal fusion (PSF) for congenital scoliosis. CASE PRESENTATION: A 14-year-old male presented with congenital scoliosis associated with T3 and T10 hemivertebrae. Preoperative Cobb angle of proximal thoracic (PT) and main thoracic (MT) curves were 50° and 41°, respectively. PSF (T1-L1) without hemivertebrectomy was performed, and the curves were corrected to 31° and 21° in the PT and MT curves, respectively, without any abnormal findings in IONM, blood pressure, or hemoglobin level. However, postoperative neurological examination revealed complete loss of motor function. A revision surgery, release of the curve correction by removing the rods, was immediately performed and muscle strength completely recovered on the first postoperative day. Five days postoperatively, PSF was achieved with less curve correction (36° in the PT curve and 26° in the MT curve), without postoperative neurological deficits. DISCUSSION: Possible mechanisms of DPND in our patient are spinal cord ischemia due to spinal cord traction caused by scoliosis correction and spinal cord kinking by the pedicle at the concave side. Understanding the possible mechanisms of intra- and postoperative neural injury is essential for appropriate intervention in each situation. Additionally, IONM should be continued to at least skin closure to detect DPND observed in our patient.

Neck and shoulder pain in thoracic adolescent idiopathic scoliosis 10 years after posterior spinal fusion.

PURPOSE: We aimed to determine the clinical significance of neck and shoulder pain (NSP) 10 years after posterior spinal fusion (PSF) for thoracic adolescent idiopathic scoliosis (AIS) and the relationship between radiographic parameters and NSP. METHODS: Of 72 patients who underwent PSF for thoracic AIS (Lenke 1 or 2) between 2000 and 2013, we included 52 (46 females; Lenke type 1 in 34 patients and type 2 in 18; mean age, 25.6 years) who underwent NSP evaluation using visual analog scale (VAS, 10 cm) 10 years postoperatively (follow-up rate, 72.2%). Correlation analyses were performed using Spearman's rank correlation coefficient (r). RESULTS: The VAS for NSP was 2.6 cm in median and 3.4 cm in mean at 10 years. The VAS had significant negative correlations with several SRS-22 domain scores (rs = - 0.348 for pain, - 0.347 for function, - 0.308 for mental health, and - 0.372 for total) (p < 0.05). In addition, the VAS score was significantly correlated with cervical lordosis (CL) (rs = 0.296), lumbar lordosis (rs = - 0.299), and sacral slope (rs = 0.362) (p < 0.05). Furthermore, at the 10-year follow-up, CL was significantly negatively correlated with T1 slope (rs = - 0.763) and thoracic kyphosis (TK) (- 0.554 for T1-12 and - 0.344 for T5-12) (p < 0.02). CONCLUSION: NSP was associated with deterioration in SRS-22 scores, indicating that NSP is a clinically significant long-term issue in PSF for thoracic AIS. Restoring or maintaining the TK and T1 slopes, which are controllable factors during PSF, may improve cervical lordosis and alleviate NSP at 10-year follow-up.

Omega-conotoxin MVIIA reduces neuropathic pain after spinal cord injury by inhibiting N-type voltage-dependent calcium channels on spinal dorsal horn.

Spinal cord injury (SCI) leads to the development of neuropathic pain. Although a multitude of pathological processes contribute to SCI-induced pain, excessive intracellular calcium accumulation and voltage-gated calcium-channel upregulation play critical roles in SCI-induced pain. However, the role of calcium-channel blockers in SCI-induced pain is unknown. Omega-conotoxin MVIIA (MVIIA) is a calcium-channel blocker that selectively inhibits N-type voltage-dependent calcium channels and demonstrates neuroprotective effects. Therefore, we investigated spinal analgesic actions and cellular mechanisms underlying the analgesic effects of MVIIA in SCI. We used SCI-induced pain model rats and conducted behavioral tests, immunohistochemical analyses, and electrophysiological experiments (in vitro whole-cell patch-clamp recording and in vivo extracellular recording). A behavior study suggested intrathecal MVIIA administration in the acute phase after SCI induced analgesia for mechanical allodynia. Immunohistochemical experiments and in vivo extracellular recordings suggested that MVIIA induces analgesia in SCI-induced pain by directly inhibiting neuronal activity in the superficial spinal dorsal horn. In vitro whole-cell patch-clamp recording showed that MVIIA inhibits presynaptic N-type voltage-dependent calcium channels expressed on primary afferent Aδ-and C-fiber terminals and suppresses the presynaptic glutamate release from substantia gelatinosa in the spinal dorsal horn. In conclusion, MVIIA administration in the acute phase after SCI may induce analgesia in SCI-induced pain by inhibiting N-type voltage-dependent calcium channels on Aδ-and C-fiber terminals in the spinal dorsal horn, resulting in decreased neuronal excitability enhanced by SCI-induced pain.

Anatomical Pelvic Parameters Using the Anterior Pelvic Plane: Normative Values and Estimation of the Standing Sagittal Alignment in Healthy Volunteers.

Introduction: In this study, we aim to estimate the natural standing sagittal alignment in patients with adult spinal deformity (ASD), firstly by investigating the normative values of anatomical pelvic parameters based on the anterior pelvic plane (APP) in a healthy population, and to clarify the relationships between the anatomical and positional pelvic parameters in standing position. Methods: The images of biplanar slot-scanning full-body stereoradiography in 140 healthy Japanese volunteers (mean age, 39.5 years; 59.3% female) were examined. In addition to three-dimensional measurements including pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT), the APP angle (APPA; anterior tilting=positive) was measured as the angle between the APP and the vertical line using the two-dimensional lateral image. Anatomical SS and PT (aSS and aPT) were calculated as the angles of SS and PT in reference to APP. Results: The mean (range) values of APPA, aSS, and aPT were determined to be 0.7° (-16.8°/15.5°), 36.8° (18.3°/64.9°), and 13.2° (-0.6°/28.7°), respectively. Moreover, SS was found to be significantly correlated with PI and aSS, while PT was significantly correlated with PI, aSS, aPT, and body weight. Also, PT was significantly larger in females than in males. Multiple linear regression analysis deduced the following equations: SS=0.404×aSS+0.203×PI+12.463, PT=-0.391×aSS+0.774×PI+1.950×sex (male=0, female=1)-12.971, wherein aSS had the greatest effect for predicting SS among the included factors and PI had the greatest effect for predicting PT. In addition, no significant differences were noted between PT/PI and aPT/PI. Conclusions: As per the results of this study, significant correlations were noted among parameters and predicting models for positional parameters (SS and PT) using anatomical parameters (aSS and aPT) in a healthy population. This novel measurement concept based on the APP has been considered to be useful in estimating natural SS and PT in standing position using the anatomical pelvic parameters in patients with ASD.

Usefulness of the spectral shaping dual-source computed tomography imaging technique in posterior corrective fusion for adolescent idiopathic scoliosis.

PURPOSE: Since childhood exposure to radiation has been demonstrated to increase cancer risk with increase in radiation dose, reduced radiation exposure during computed tomography (CT) evaluation is desired for adolescent idiopathic scoliosis (AIS). Therefore, this retrospective study aimed to investigate the radiation dose of dual-source CT using a spectral shaping technique and the accuracy of the thoracic pedicle screw (TPS) placement for posterior spinal fusion (PSF) in patients with AIS. METHODS: Fifty-nine female patients with thoracic AIS who underwent PSF using CT-guided TPSs were included and divided into two groups comprised of 23 patients who underwent dual-source CT (DSCT) with a tin filter (DSCT group) and 36 who underwent conventional multislice CT (MSCT group). We assessed the CT radiation dose using the CT dose index (CTDIvol), effective dose (ED), and accuracy of TPS insertion according to the established Neo's classification. RESULTS: The DSCT and MSCT groups differed significantly (p < 0.001) in the mean CTDIvol (0.76 vs. 3.31 mGy, respectively) and ED (0.77 vs. 3.47 mSv, respectively). Although the correction rate of the main thoracic curve in the DSCT group was lower (65.7% vs. 71.2%) (p = 0.0126), the TPS accuracy (Grades 0-1) was similar in both groups (381 screws [88.8%] vs. 600 screws [88.4%], respectively) (p = 0.8133). No patient required replacement of malpositioned screws. CONCLUSION: Spectral shaping DSCT with a tube-based tin filter allowed a 75% radiation dose reduction while achieving TPS insertion accuracy similar to procedures based on conventional CT without spectral shaping.

Characteristics of back pain in patients with adolescent idiopathic scoliosis: Considerations in candidates for corrective surgery.

BACKGROUND: Previous studies have demonstrated that the point prevalence of back pain ranges from 12 % to 33 % and that the lifetime prevalence of back pain ranges from 28 % to 51 % in adolescents. However, few studies on back pain in patients with Adolescent idiopathic scoliosis (AIS) have been conducted, and these studies had significant limitations, including a lack of comparative controls and detailed information about scoliotic deformity or pain location. This study aimed to determine whether adolescents with AIS experience back pain in specific regions. METHODS: This retrospective case-control study included 189 female adolescents with AIS who underwent corrective fusion from 2008 to 2020. Questionnaires on back pain and health-related quality of life (HRQOL) using the Scoliosis Research Society Outcomes Instrument-22 (SRS-22) were conducted preoperatively. The control group included 2909 general female adolescents. RESULTS: The mean Cobb angles in the main thoracic and thoracolumbar/lumbar curves were 51.4 ± 15.3° and 40.4 ± 12.9°. Back pain characteristics included higher point prevalence (25.9 %) and lifetime prevalence (64.6 %) compared to healthy controls. Adolescents with back pain showed lower scores in the pain and mental health domains of the SRS-22. Adolescents with major thoracic AIS showed more back pain in the upper and middle right back compared to adolescents with major thoracolumbar/lumbar AIS. CONCLUSION: The point and lifetime prevalence of back pain were definitely higher in patients with AIS, which affected their HRQOL. There was a relationship between pain around the right scapula and the right major thoracic curve with a rib hump deformity.

Gait Analysis by the Severity of Gait Disturbance in Patients with Compressive Cervical Myelopathy.

Introduction: Gait disturbance due to compressive cervical myelopathy has been previously described. However, data on how gait disturbance varies with the degree of lower extremity motor impairment are limited. Therefore, we investigated the characteristics of gait analysis based on severity and determined how gait disturbance progresses in compressive cervical myelopathy. Methods: We enrolled 44 patients (32 men and 12 women; mean age, 65.0 years) out of 108 consecutive patients with compressive cervical myelopathy who underwent spinal cord decompression surgery in our hospital. The exclusion criteria were inability to gait and complications affecting gait. Twenty-two patients with Japanese Orthopaedic Association scores 1 or 2 for lower extremity motor functions were assigned to the severe group, and 22 patients who scored 3 or 4 were assigned to the moderate group. Gait analysis was performed preoperatively using a long thin-type sensor sheet, and 25 healthy volunteers were assigned to the control group. Results: Stride length, swing phase, and gait speed decreased whereas step angle, stance phase, and double support duration increased as myelopathy progressed. Step width was significantly larger in the severe group than in the moderate and control groups. The cutoff values based on severe myelopathy with the inability to ascend or descend stairs without support were 60% for the stride length percentage of body height and 100 cm/s for gait speed. Conclusions: Decreases in stride length, swing phase, and gait speed and increases in step angle, stance phase, and double support duration are compensatory changes as cervical myelopathy progresses. Step width is a compensatory change that is not significantly altered in moderate myelopathy but increases when gait becomes affected, such that the patient cannot ascend or descend stairs without support.

Usefulness and limitations of intraoperative pathological diagnosis using frozen sections for spinal cord tumors.

BACKGROUND: Intraoperative pathological diagnosis has a major influence on the intra- and postoperative management of spinal cord tumors. Thus, the aim of this study was to assess the reliability of intraoperative pathological diagnosis for spinal cord lesions by comparing it with the final pathological diagnosis and to determine its usefulness and limitations. METHOD: Three-hundred and three consecutive patients (mean age, 53.9 years) with neoplastic spinal cord lesions who underwent initial surgery between 2000 and 2021 were included. The anatomical locations of the spinal cord tumors and the implementation rate of intraoperative pathological diagnosis in each tumor type were evaluated. As the primary outcome, we determined the concordance rates between the intraoperative pathological diagnosis and the final diagnosis. When the intraoperative pathological diagnosis and final diagnosis were the same, the diagnosis was defined as a "match." Otherwise, the diagnosis was defined as a "mismatch." RESULTS: The overall implementation rate of intraoperative pathological diagnosis was 53%, with implementation rates of 71%, 45%, 47%, and 50% for intramedullary, intradural extramedullary, extradural, and dumbbell tumors, respectively. The overall concordance rate was 87.6%, with concordance rates of 80%, 95%, 75%, and 90% for intramedullary, intradural extramedullary, extradural, and dumbbell tumors, respectively (p < 0.05). The diagnoses of ependymomas, low-grade astrocytomas, and high-grade astrocytomas was occasionally difficult among intramedullary tumors. Among intradural extramedullary tumors, differentiation between grade 1 meningioma and high-grade meningioma was difficult using intraoperative pathological diagnosis. CONCLUSIONS: Surgeons must recognize the lower accuracy of intraoperative pathological diagnosis for intramedullary and extradural lesions and make a final decision by considering the intraoperative gross findings, preoperative clinical course, and imaging.

Impact of spinal sagittal malalignment on locomotive syndrome and physical function in community-dwelling middle aged and older women.

BACKGROUND: Adult spinal deformity has a substantially debilitating effect on older people's physical and mental health. However, the impact of sagittal malalignment on locomotive syndrome (LS), sarcopenia, and physical function in community-dwelling older women has not yet been clarified. This study aimed to investigate the association between these factors in community-dwelling middle aged and older women. METHODS: A total of 361 women were recruited from participants performing aquatic exercises in a rural area of Japan. The body mass index, skeletal muscle mass index, trunk muscle mass, spinal inclination angle (SIA), grip strength, timed up-and-go test (TUG), maximum stride of the participants, and one-leg standing time were measured. Low back pain (LBP)- and health-related quality of life (HRQOL) were evaluated using the Oswestry Disability Index (ODI) and the Short-Form 8 questionnaire. Associations between the global sagittal alignment using SIA and investigating parameters were analyzed. RESULTS: The prevalence of sarcopenia was 3.6%. The prevalence of LS (stages 1, 2, and 3) was 43.8% (158 of 361), and the number of participants in each LS stage was 203 (stage 0), 95 (stage 1), 28 (stage 2), and 35 (stage 3). The SIA was significantly correlated with the 25-question geriatric locomotive function scale (r' = 0.292, p < 0.001), ODI (r' = 0.267, p < 0.001), and TUG (r' = 0.453, p < 0.001) after adjusting for age. In the receiver-operating characteristic curve analysis, the cutoff values of SIA for LS ≥ stage 2 and ODI ≥ 20% were 5°. CONCLUSIONS: LBP-related QOL and physical performance were significantly associated with global sagittal alignment. Global sagittal alignment was correlated with the three-stage category of LS. The spinal inclination of 5° was a cutoff value to predict exacerbation of mobility function and HRQOL status.

Determining factors that maintain physical function or increase frailty using the Kihon checklist among community-dwelling older adults: a six-year longitudinal study in Agano, Japan.

BACKGROUND: A significant increase in the older adult population in Japan will significantly increase healthcare costs. This study aimed to examine the risk factors contributing to robustness transitioning to frailty in older residents. METHODS: Participants were aged 70 in 2016 and 76 in 2022. Participants were evaluated using the Kihon Checklist (KCL). RESULTS: Participants for this longitudinal study included 444 older persons who completed the KCL surveys in 2016 and 2022. The follow-up rate was 80.6%; therefore, 358 participants were included in the analysis. The median KCL score increased significantly from 2 to 2016 to 3 in 2022 (p < 0.001). The prevalence of robustness significantly decreased from 60.9 to 48.6% (p = 0.042). In a stepwise logistic regression analysis, robustness was independently associated with regular continuous walks for 15 min and a body mass index of above 18.5%. The following variables were associated with the transition to prefrailty: experiencing a fall in the past year and not going out at least once a week. For the transition to frailty, the variables were turned to family or friends for advice, experienced a fall in the past year, and felt helpless in the last two weeks. The independent factor for the transition from prefrailty to frailty was having a BMI of less than 18.5. In contrast, the independent factor for improving from frailty to robustness or prefrailty was going out at least once a week. CONCLUSIONS: We recommend maintaining continuous walking for more than 15 min, maintaining a BMI of at least 18.5, and going out more than once a week to improve being house-bounded and depressive mood, not only to prevent the transition to prefrailty or frailty but also to improve frailty.

Predictive biomarkers of ossification progression and bone metabolism dynamics in patients with cervical ossification of the posterior longitudinal ligament.

PURPOSE: This study aimed to establish biomarkers to predict the progression of ossification by examining ossification volume and bone metabolism dynamics in patients with ossification of the posterior longitudinal ligament (OPLL). METHODS: We assessed OPLL progression using computed tomography-based three-dimensional (3D) image analysis and examined bone metabolism dynamics in 107 patients with OPLL (men, 72; women, 35; mean age, 63.6 years). The volume of OPLL was calculated twice during the follow-up period, and OPLL progression was evaluated by the annual rate of ossification increase. Bone metabolism dynamics were assessed by routine blood tests and analysis of various serum biomarkers (including 25-hydroxyvitamin D, intact parathyroid hormone, fibroblast growth factor 23, intact N-terminal propeptide of type 1, tartrate-resistant acid phosphatase isoform 5b, sclerostin, and Dickkopf-1) and bone mineral density (BMD). Patients were classified into the progression (P) or non-progression (NP) group according to the annual rate of increase in previous 3D image analyses, and associated factors between these groups were compared. RESULTS: The P and NP groups consisted of 29 patients (23 men and 6 women) and 78 patients (49 men and 29 women), respectively. Univariate analysis revealed significant differences in terms of age, body mass index, serum phosphorus, serum sclerostin, and BMD. In multivariate analysis, age, serum phosphorus, and serum sclerostin were identified as independent factors associated with OPLL progression. CONCLUSION: Younger age, hypophosphatemia, and high serum sclerostin are risk factors for OPLL progression. Serum phosphorus and sclerostin could serve as important biomarkers for predicting ossification progression.

Marriage and childbirth of patients who were surgically and non-surgically treated for adolescent idiopathic scoliosis: a survey at the age of 30 years or older.

PURPOSE: We aimed to investigate the marital status and childbirth in adolescent idiopathic scoliosis (AIS) patients. METHODS: This study included women who were treated surgically or non-surgically for AIS with a scoliosis magnitude ≥ 30° before surgery or at skeletal maturity and were followed up until age 30 years or older. Patients were divided into surgically treated (S-AIS, n = 55) and non-surgically treated AIS groups (N-AIS, n = 86). Data from the national fertility survey were used as control values. RESULTS: There were no significant differences in age at the final follow-up between the S- (40.7 years) and N-AIS (42.1 years) groups. The unmarried rate among all women and the nulliparous rate among married women in the S-AIS group (29.1% and 18.4%, respectively) were similar to those in the N-AIS group (26.7% and 16.1%, respectively). The mean number of children per married woman also did not differ between the S- and N-AIS groups (1.5 vs 1.4). Compared to the control group, after adjusting for age, the common odds ratio in the AIS group was 1.56 (p = 0.031) for unmarried status and 1.88 (p = 0.026) for nulliparity among married women. Moreover, the mean number of children per married woman was significantly lower in the AIS group than in the control group (1.3 vs 1.7, p < 0.001). CONCLUSION: Surgically and non-surgically treated women with AIS had a similar status with regard to marriage and childbirth, while women with AIS were more likely to be unmarried and nulliparous and to have fewer children compared to the nationwide population.

Association of success of brace treatment and various aspects of in-brace correction in patients with adolescent idiopathic scoliosis.

BACKGROUND: Although skeletal maturity and brace wear time contribute to the success of brace treatment in adolescent idiopathic scoliosis (AIS), the extent of initial in-brace correction for ensuring successful outcomes remains unclear. We hypothesized that the degree of initial in-brace correction correlates with brace success in patients with AIS. METHOD: The study included 135 AIS patients with a major Cobb angle of 20°-40° treated with a thoracic lumbosacral orthosis for at least one year and followed up for skeletal maturity. The subjects were divided into two groups: the skeletally immature group (group I, n = 72), who met the Bracing in Adolescent Idiopathic Scoliosis Trial study protocol at the start of brace treatment, and the skeletally mature group (group M, n = 63). Treatment success was defined as not needing surgical treatment and a major Cobb angle <40° at the end of brace treatment. RESULTS: In both groups, the mean major Cobb angles before treatment, while wearing the brace, and at the end of brace treatment were 30.6°/31.7°, 22.9°/24.2°, and 38.8°/33.9° (p < 0.05), respectively, and the treatment success rate was 56.9% and 77.8%, respectively (p < 0.05). Univariate regression analysis revealed the following risk factors: Risser grade 0 in group I, major Cobb angles before treatment, initial in-brace major Cobb angle, and in-brace correction rate in both groups. Cutoff values of in-brace major Cobb angle for treatment success calculated by ROC curve in groups I and M were 24° and 29°, respectively. CONCLUSIONS: In-brace major scoliosis correction of <25° in patients with immature skeletal status and <30° in patients with mature skeletal structure should be aimed at to achieve significant brace treatment success.

Axial Neck-Shoulder Pain After Posterior Correction and Fusion for Adolescent Idiopathic Scoliosis With Structural Thoracic Curve: Does Cranial Fusion Level Affect Neck Symptoms?

STUDY DESIGN: A retrospective cohort study using prospectively collected data. OBJECTIVES: To investigate the incidence and impact of fusion to the upper thoracic spine on neck-shoulder symptoms after posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Axial neck-shoulder pain is established as a sequela of posterior cervical spine surgery and is mainly caused by the dissection of extensor muscles in the cervical and upper thoracic spine. MATERIALS AND METHODS: Sixty-three female patients with AIS who underwent PSF using segmental pedicle screw constructs for structural main thoracic curve with a minimum 2-year follow-up were included. Axial neck-shoulder pain was assessed using the visual analog scale and cervical spine function domain score of the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire. The patients were divided into 2 groups, a higher group (underwent fusion up to T3 or above, n=27) and a lower group (underwent fusion up to T4 or below, n=36), and radiologic and clinical outcomes were compared. RESULTS: The incidence of axial neck-shoulder pain (visual analog scale ≥30) preoperatively and at the 2-year follow-up was 29 and 40%, respectively. The pain and mental health domains of the Scoliosis Research Society-22 and cervical spine function domain of the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire were correlated with the severity of axial neck pain. In the comparison of clinical outcomes between the 2 groups, the pain domain score of the Scoliosis Research Society-22 in the lower group was significantly better than that in the higher group at the 2-year follow-up ( P <0.05). Other parameters showed no significant differences preoperatively or at the 2-year follow-up. CONCLUSION: Female patients with AIS had a relatively high incidence of axial neck-shoulder pain after PSF, which affected their health-related quality of life. Both groups showed similar clinical outcomes, and the cranial fusion level did not affect axial neck-shoulder pain and cervical spine function. LEVEL OF EVIDENCE: Level 3.

Dynamics of surgical smoke in the operating room during spinal surgery: Comparison of particulate matter 2.5-air concentration between the electric scalpel with and without a smoke evacuation pencil: A cross-sectional study.

BACKGROUND: Surgical smoke is a vaporous by-product generated during tissue incision and cauterization with an electric scalpel. This smoke contains tissue- and blood/vascular-derived substances, bacteria, viruses, and chemical substances. Among them, it contains many fine particles called particulate matter (PM) 2.5, which are harmful and hazardous to the human body. We aimed to investigate the occurrence of PM2.5 in surgical smoke produced during spinal surgery and to evaluate the efficacy of an electric scalpel with a smoke evacuation pencil. METHODS: In this retrospective observational study, 89 patients who underwent spinal surgery between June 2019 and May 2021 were included. A dust monitor was installed in the operating room to measure the PM2.5 air concentration during the surgery. During each surgery, the total amount of PM2.5, the maximum PM2.5 air concentration, the exposure time to PM2.5, and the average value of PM2.5 air concentration from the start to the end of the surgery were calculated. RESULTS: We found that in 29 of the 89 cases (32.6%), the air concentration of PM2.5 increased to a level that could cause health damage during the surgery. Twelve cases (13.4%) reached the level that could cause serious health damage, and 8 cases (9%) reached an emergency warning level. The total amount and the maximum and average levels of PM2.5 were significantly suppressed in the surgery with a smoke evacuation pencil group than in the surgery without a smoke evacuation pencil group. CONCLUSION: We detected hazardous levels of PM2.5 in the air during spinal surgery, highlighting the importance of considering smoke control or reduction during spinal surgery. We recommend using an electric scalpel with a smoke evacuation pencil for regulating PM2.5 levels in the operating room.

Evaluating flexibility and predicting curve correction using fulcrum-bending radiographs in Lenke type 2 adolescent idiopathic scoliosis.

BACKGROUND: Fulcrum-bending (FB) correction is considered to provide the best estimation of main thoracic (MT) curve flexibility and postoperative correction in surgical treatment for adolescent idiopathic scoliosis (AIS). However, few studies evaluated the usefulness of FB radiographs for proximal thoracic (PT) curve. We aimed to perform flexibility assessments using both active side-bending (SB) and FB radiographs and evaluate surgical outcomes after posterior spinal fusion (PSF) for Lenke type 2 AIS. METHODS: This study included 38 consecutive patients with Lenke type 2 AIS who underwent PSF using a pedicle screw construct with a minimum 2-year follow-up. Radiographic parameters, including correction rate, SB and FB flexibility, and FB correction index (FBCI: [correction rate/FB flexibility] × 100), were evaluated preoperatively, immediately after surgery, and at the 2-year follow-up. The clinical outcomes were preoperatively evaluated using the Scoliosis Research Outcomes Instrument-22 and at the follow-up. RESULTS: All scoliosis curves significantly improved and shoulder balance shifted toward left shoulder elevation (all comparisons, p < 0.0001). There were significant differences between the SB and FB corrections in the PT and MT curves (p < 0.0001). The magnitudes of the discrepancies between the SB and FB corrections in the PT and MT curves were 11.2° ± 5.2° and 11.6° ± 7.2°, respectively. FB correction did not differ from postoperative Cobb angles correction immediately after surgery or at the 2-year follow-up; the mean FBCIs in the PT and MT curves were 98.8% and 105.5%, respectively. The self-image domain SRS-22 scores had significantly increased at the 2-year follow-up (p < 0.0001). CONCLUSIONS: There were significant differences between the SB and FB corrections, and FB correction tended to approximate the postoperative curve correction (FBCI = 100%) for PT and MT curves in patients with Lenke type 2 AIS. FB flexibility is more reliable than SB flexibility in evaluating actual curve flexibility even for the PT curve.

Mid- to Long-Term Outcomes After Resection of Thoracic Dumbbell Tumors Managed by Laminectomy and Unilateral Total Facetectomy Without Instrumented Fusion.

STUDY DESIGN: Retrospective multicenter study. OBJECTIVE: To evaluate mid- to long-term surgical outcomes of thoracic dumbbell tumors managed by laminectomy and unilateral total facetectomy without instrumented fusion. METHODS: A total of 15 patients with thoracic dumbbell tumors who underwent primary resection by laminectomy and unilateral total facetectomy without spinal instrumented fusion between 2000 and 2015 were reviewed. Patient characteristics, surgical outcomes (including spinal alignment and stability), disc degeneration, pain, disability, and health-related quality of life were evaluated. Additionally, to analyze the impact of the affected levels on these outcomes, we divided the patients into 2 groups: a middle thoracic group and a thoracolumbar group. RESULTS: The mean duration of follow-up was 100.5 months (range, 36-190 months). The affected level was T3-T4 or below in all patients. Although the local kyphosis angle (8.1° to 12.7°), thoracic kyphosis angle (25.6° to 33.9°), and coronal Cobb angle (6.6° to 9.5°) significantly increased from preoperative to the final visit (P ≤ .02), no patient demonstrated spinal instability. From magnetic resonance imaging, no patient had a worse grade of disc degeneration in the affected level than those in the adjacent levels. The percentage of patients who presented with an Oswestry disability index ≤ 22% was 80%. Moreover, the surgical region did not adversely affect the outcomes. No patient required additional surgery due to spinal instability or deformity. CONCLUSIONS: Unilateral total facetectomy without fusion to resect thoracic dumbbell tumors caused neither spinal deformity nor instability requiring additional surgery at the mid- to long-term follow-up.

Low back pain significantly influences locomotive syndrome in older people: Evaluation using the 3-stage categories.

BACKGROUND: The Japanese Orthopaedic Association (JOA) introduced the concept of locomotive syndrome (LS), which indicates a decline in mobility function by musculoskeletal disorders with new 3-staged category. Additionally, sarcopenia indicates a decline in the quantity and/or quality of skeletal muscle. However, the relationship between low back pain (LBP) and LS or sarcopenia in older people has not been sufficiently understood. This study aimed to investigate the association between them through a cross-sectional locomotorium survey. METHODS: A total of 302 participants were drawn from the aquatic exercise participants in a rural area of Japan. The body mass index, body fat percentage, skeletal muscle mass index (SMI), spinal inclination angle (SIA), grip strength, timed up-and-go test (TUG), and maximum stride of the participants were measured. LBP and LBP-related quality of life (QOL) were evaluated using the Oswestry Disability Index (ODI), visual analogue scale (VAS) of LBP, and the Short-Form 8 (SF-8). Associations between the investigating parameters and sarcopenia or LS were analyzed. RESULTS: There were no significant differences in the findings except grip strength between the non-sarcopenia and sarcopenia groups. However, the LS group showed significantly larger SIA, higher ODI, higher VAS of LBP, lower physical component score (PCS) of the SF-8, longer time in TUG, and lower value in maximum stride than the non-LS group. In addition, the ODI and PCS of the SF-8 significantly deteriorated as the LS stage progressed, and the GLFS-25 score was significantly correlated with ODI (r = 0.706, p < 0.001) and PCS (r = -0.643, p < 0.001) scores. CONCLUSIONS: LBP, LBP-related QOL, and physical performance were found to be significantly associated with LS, not sarcopenia, with LBP-related QOL and physical function being closely correlated with 3-stage categories of LS. Thus, these results suggested that LBP is a key factor for LS prevalence.