Full endoscopic surgery for calcium pyrophosphate deposition disease (CPPD) in the cervical ligamentum flavum: report of two cervical myelopathy cases.

Calcium pyrophosphate deposition disease (CPPD), known as pseudogout, is characterized by the accumulation of calcium pyrophosphate crystals in musculoskeletal structures, primarily joints. While CPPD commonly affects various joints, involvement in the cervical spine leading to myelopathy is rare. Surgical intervention becomes necessary when conservative measures fail, but reports on full endoscopic surgeries are extremely rare. We present two successful cases where full endoscopic systems were used for CPPD removal in the cervical spine. The surgical technique involved a full endoscopic approach, adapting the previously reported technique for unilateral laminotomy bilateral decompression. Full-endoscopic removal of cervical CPPD inducing myelopathy were successfully removed with good clinical and radiologic outcomes. The scarcity of endoscopic cases for cervical ligamentum flavum CPPD is attributed to the condition's rarity. However, our successful cases advocate for endoscopic surgery as a potential primary treatment option for CPPD-induced cervical myelopathy, especially in elderly patients or those with previous cervical operation histories. This experience encourages the consideration of endoscopic surgery for managing cervical ligamentum flavum CPPD as a viable alternative.

Postoperative survival after lumbar instrumented surgery for metastatic spinal tumors: a nationwide population-based cohort analysis.

BACKGROUND: It is difficult to predict the expected survival after lumbar instrumented surgery for metastases owing to the difference among different cancer origins and the relatively short survival after surgery. AIMS: The aim of this study is to analyze the postoperative survival period of lumbar spinal metastasis patients who underwent lumbar instrumented surgery. METHODS: Data were collected from the Korean National Health Insurance Review and Assessment Service database. Patients who underwent lumbar spinal surgery with instrumentation between January 2011 and December 2015 for metastatic lumbar diseases were reviewed. The mean postoperative survival period of patients with metastatic lumbar cancer according to each primary cancer type was evaluated. RESULTS: A total of 628 patients were enrolled and categorized according to primary cancer type. The overall median survival rate was 1.11±1.30 years. The three most prevalent primary cancer groups were lung, hepatobiliary, and colorectal cancers, presenting relatively short postoperative survival rates (0.93±1.25, 0.74±0.75 and 0.74±0.88 years, respectively). The best postoperative survival period was observed in breast cancer (2.23±1.83 years), while urinary tract cancer showed the shortest postoperative survival period (0.59±0.69 years). CONCLUSION: The postoperative survival period of patients with lumbar metastatic spinal tumors according to different primary cancers after instrumented fusion was ˃1 year overall, with differences according to different primary origins. This result may provide information regarding the expected postoperative survival after instrumented surgery for lumbar spinal metastases.

A quantitative analysis of surgical smoke-derived particulate matter and formaldehyde exposure during spine surgery: a possible occupational hazard.

OBJECTIVE: Since its introduction, electrocautery has served as a valuable surgical tool, enabling precise tissue cutting and effective hemostasis in spine surgery. While there have been numerous efforts to elucidate the possible hazardous effects of surgical smoke in various surgical fields, there has been very little discussion in the context of spine surgery. The objective of this study was to measure and conduct a quantitative analysis of the particulate matter (PM) of different sizes and of formaldehyde (HCHO) generated by smoke during spine surgeries. METHODS: This study included a consecutive series of patients who underwent 1- or 2-level lumbar spinal fusion surgery between June and November 2021. Particle counts were measured using a particle counter, specifically focusing on six different sizes of PM (0.3, 0.5, 1, 2.5, 5, and 10 µm). Additionally, measurements were taken for HCHO in parts per million (ppm). Monopolar cautery was used in the surgical setting. Systematic measurements were conducted at specific time points during the surgical procedures to assess the levels of PM and HCHO. Furthermore, the efficacy of surgical smoke suction was evaluated by comparing the PM levels with and without adjacent placement of suction. RESULTS: This study involved 35 patients, with measurements of both PM and HCHO taken in 27 cases. The remaining 8 cases had measurements only for PM. In this study, statistically significant quantitative changes in various PM sizes were observed when electrocautery was used during spine surgery (12.3 ± 1.7 vs 1975.7 ± 422.8, 3.4 ± 0.5 vs 250.1 ± 45.7, and 1.9 ± 0.2 vs 78.1 ± 13.3, respectively, for 2.5-, 5-, and 10-µm PM; p < 0.05). The level of HCHO was also significantly higher (0.085 ± 0.006 vs 0.131 ± 0.014 ppm, p < 0.05) with electrocautery use. Utilization of adjacent suction of surgical smoke during electrocautery demonstrated a statistically significant reduction in PM levels. CONCLUSIONS: The findings of this study highlight the potential surgical smoke-related hazards that spine surgeons may be exposed to in the operating room. Implementing simple interventions, such as utilizing nearby suction, can effectively minimize the amount of toxic surgical smoke and mitigate these risks.

Psychosocial Effect of Brace Treatment in Adolescent Idiopathic Scoliosis: A Study Using EQ-5D.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To evaluate psychosocial effect of brace treatment in adolescent idiopathic scoliosis (AIS) using EuroQoL 5-dimension (EQ-5D) depression and anxiety category. BACKGROUND: AIS is a structural abnormality of the spine often affecting patients during the puberty, a critical period of developing psychosocial problems. Many questionnaires had been adapted to evaluate mental health and health-related quality of life of AIS patients. However, these questionnaires are often time consuming and difficult to obtain. Therefore, a simpler substitute-EQ-5D-was evaluated. METHODS: This is a single-center retrospective cohort analysis of adult idiopathic scoliosis patients aged between 8 and 19, visiting outpatient's clinic. Beck's depression inventory, EQ-5D and EuroQoL visual assessment scale, and Objectified Body Consciousness Scale for Youth were compared between brace group and non-brace group of AIS patients. Furthermore, difference between male and female were evaluated within brace group. RESULTS: None of the questionnaire showed significant difference between brace and non-brace group. However, when male and female patients were compared within brace group, female patients were significantly more susceptible to depression and anxiety based on EQ-5D and body consciousness. Furthermore, depression and anxiety according to both BDI and EQ-5D were significantly correlated to health-related quality of life. CONCLUSION: During brace treatment of female AIS patients, psychosocial status played a significant role in health-related quality of life. EQ-5D is a simple way to monitor the mental health status.

Radiologic risk factors associated with development of myelopathy in patients with ossification of the posterior longitudinal ligament of the cervical spine.

STUDY DESIGN: Retrospective Cohort Study OBJECTIVE: Myelopathy following ossification of the posterior longitudinal ligament (OPLL) is one of the devastating clinical features in these patients, while we still know little about which factors are associated with development of myelopathy. We evaluated the difference of radiologic measurements between OPLL patients with or without myelopathy and searched for the clinical significance with emphasis on the impact of dynamic motion. METHODS: 305 patients diagnosed of OPLL were enrolled for retrospective review. They were divided into two groups according to the coexistence of radiographic evidence of myelopathy. Demographic data as well as radiologic measures including the presence of disc degeneration (DD), anterior-posterior diameter (APD) of central canal, canal compromise (CC) ratio, global and segmental range of motion (gROM and sROM), OPLL type (morphologic classification) and K-line were collected. RESULTS: APD (odds ratio (OR); 0.411), CC ratio (OR; 1.100) and sROM (OR; 1.371) were significantly associated with the presence of myelopathy in the multivariate analysis. While the statistically significant factors were same in OPLLs with CC larger than 50%, presence of DD (OR; 4.509) and sROM (OR; 1.295) were significantly associated with myelopathy but not the CC itself in OPLLs with CC smaller than 50%. CONCLUSIONS: We discovered that the APD, CC ratio and sROM had significant association with development of myelopathy in OPLLs. And the presence of dynamic factors had significant association with myelopathy in OPLLs with smaller CC ratios. This observation and its clinical significance on development of myelopathy might enhance our understanding of OPLL.

Use of prophylactic perioperative antibiotics for lumbar spinal fusions: A nationwide population-based cohort study.

BACKGROUND: Perioperative prophylactic antibiotic (PPA) use in spine surgery is known to reduce the rate of surgical site infections. In the past decade, several evidence-based guidelines have been published and surveillance systems to monitor the proper use of antimicrobials had been adapted by many institutes. OBJECTIVE: To report the trends of PPA prescription in lumbar fusion surgeries nationwide in the Republic of Korea. METHODS: This is a nationwide registry study. Using the population-based data from the Republic of Korea provided by the Korean Health Insurance Review and Assessment Service, data of all lumbar spinal fusion surgeries performed between 2010 and 2018 in adult patients (age ≥19 years) were reviewed. RESULTS: The most frequently used antibiotics were first-generation cephalosporins, which accounted for 38.2 % of total PPA prescriptions and were prescribed in 58.96 % of lumbar fusion surgeries. A gradual increase in prescription trends was observed. The second most frequently used PPAs were second-generation cephalosporins, which showed decrease in use from 2016. The frequency of vancomycin prescriptions gradually increased over the observation period and showed an almost four-fold increase in 2018 compared to 2010. First- and second-generation cephalosporins were prescribed less frequently to patients with renal disease. CONCLUSION: The pattern of PPA use has changed remarkably over the observation period. Furthermore, specific differences in PPA prescriptions were observed among patients with certain co-morbidities.

Elucidating the effect of mechanical stretch stress on the mechanism of ligamentum flavum hypertrophy: Development of a novel in vitro multi-torsional stretch loading device.

OBJECTIVE: We developed a novel multi-torsional mechanical stretch stress loading device for ligamentum flavum cells and evaluated its influence on the development of ligamentum flavum hypertrophy, a common cause of lumbar spinal canal stenosis. MATERIALS AND METHODS: Stretch strength of the device was optimized by applying 5% and 15% MSS loads for 24, 48, and 72 h. A cytotoxicity assay of human ligamentum flavum cells was performed and the results were compared to control (0% stress). Inflammatory markers (interleukin [IL]-6, IL-8), vascular endothelial growth factor [VEGF], and extracellular matrix (ECM)-regulating cytokines (matrix metalloproteinase [MMP]-1, MMP-3 and MMP-9, and tissue inhibitor of metalloproteinase [TIMP]-1 and TIMP-2) were quantified via enzyme-linked immunosorbent assay. RESULTS: Using our multi-torsional mechanical stretch stress loading device, 5% stress for 24 hour was optimal for ligamentum flavum cells. Under this condition, the IL-6 and IL-8 levels, VEGF level, and MMP-1, MMP-3, and TIMP-2 were significantly increased, compared to the control. CONCLUSION: Using the novel multi-torsional mechanical stretch stress loading device we confirmed that, mechanical stress enhances the production of inflammatory cytokines and angiogenic factors, and altered the expression of ECM-regulating enzymes, possibly triggering ligamentum flavum hypertrophy.

Characteristics of Sagittal Spinopelvic Alignment Changes After Symptom Relief After Simple Lumbar Decompression.

BACKGROUND: Sagittal spinopelvic alignment (SSPA) parameters are essential for the diagnosis of adult spinal deformities (ASDs) and their progression. Certain clinical symptoms that occur in patients with lumbar spinal stenosis (LSS) and herniated nucleus pulposus (HNP) may distort the SSPA and mimic ASD. OBJECTIVE: To differentiate SSPA in symptomatic patients from asymptomatic patients within 10 minutes in the standing position. METHODS: This retrospective cohort study evaluated changes in SSPA after simple lumbar decompression surgery in patients with LSS and HNP. Relative sagittal alignment (RSA), relative pelvic version, relative lumbar lordosis (RLL), Lordosis Distribution Index (LDI), and global alignment and proportion (GAP) values were calculated using the conventional Schwab classification method. First, the preoperative and postoperative SSPA parameters were compared. Second, patients were subgrouped into symptomatic within 10 minutes of standing (SP group) and other symptoms of LSS and HNP as controls. Changes in SSPA parameters after symptom relief after simple lumbar decompression surgery were compared between the two groups. RESULTS: Overall, all SSPA parameters improved after surgery. However, after subgrouping, patients in the control group did not show significant SSPA alterations, except for LDI, whereas patients in the SP group significantly improved in terms of their RSA, RLL, LDI, and GAP values after symptom relief after surgery. CONCLUSION: Patients with pain on standing within 10 minutes showed significant correction in RSA, RLL, and GAP values after simple lumbar decompression. Therefore, it is important to observe such clinical symptoms to avoid misdiagnosis of ASD.

Current Knowledge and Future Therapeutic Prospects in Symptomatic Intervertebral Disc Degeneration.

Intervertebral disc (IVD) degeneration is the main source of intractable lower back pain, and symptomatic IVD degeneration could be due to different degeneration mechanisms. In this article, we describe the molecular basis of symptomatic IVD degenerative disc diseases (DDDs), emphasizing the role of degeneration, inflammation, angiogenesis, and extracellular matrix (ECM) regulation during this process. In symptomatic DDD, pro-inflammatory mediators modulate catabolic reactions, resulting in changes in ECM homeostasis and, finally, neural/vascular ingrowth-related chronic intractable discogenic pain. In ECM homeostasis, anabolic protein-regulating genes show reduced expression and changes in ECM production, while matrix metalloproteinase gene expression increases and results in aggressive ECM degradation. The resultant loss of normal IVD viscoelasticity and a concomitant change in ECM composition are key mechanisms in DDDs. During inflammation, a macrophage-related cascade is represented by the secretion of high levels of pro-inflammatory cytokines, which induce inflammation. Aberrant angiogenesis is considered a key initiative pathologic step in symptomatic DDD. In reflection of angiogenesis, vascular endothelial growth factor expression is regulated by hypoxia-inducible factor-1 in the hypoxic conditions of IVDs. Furthermore, IVD cells undergoing degeneration potentially enhance neovascularization by secreting large amounts of angiogenic cytokines, which penetrate the IVD from the outer annulus fibrosus, extending deep into the outer part of the nucleus pulposus. Based on current knowledge, a multi-disciplinary approach is needed in all aspects of spinal research, starting from basic research to clinical applications, as this will provide information regarding treatments for DDDs and discogenic pain.

A New Classification for Cervical Ossification of the Posterior Longitudinal Ligament Based on the Coexistence of Segmental Disc Degeneration.

OBJECTIVE: Classification systems for cervical ossification of the posterior longitudinal ligament (OPLL) have traditionally focused on the morphological characteristics of ossification. Although the classification describes many clinical features associated with the shape of the ossification, including the concept of spondylosis seems necessary because of the similarity in age distribution. METHODS: Patients diagnosed with OPLL who presented with increase signal intensity (ISI) on magnetic resonance imaging were surgically treated in our department. The patients were divided into two groups (pure versus degenerative) according to the presence of disc degeneration. RESULTS: Of 141 patients enrolled in this study, more than half (61%) were classified into the degenerative group. The pure group showed a profound male predominance, early presentation of myelopathy, and a different predilection for ISI compared to the degenerative group. The mean canal compromise ratio (CC) of the ISI was 47% in the degenerative group versus 61% in the pure group (p<0.0000). On the contrary, the global and segment motions were significantly larger in the degenerative group (p<0.0000 and p=0.003, respectively). The canal diameters and global angles did not differ between groups. CONCLUSION: Classifying cervical OPLL based on the presence of combined disc degeneration is beneficial for understanding the disorder's behavior. CC appears to be the main factor in the development of myelopathy in the pure group, whereas additional dynamic factors appear to affect its development in the degenerative group.

Corrigendum to "The Analysis of Biomechanical Properties of Proximal Femur after Implant Removal".

[This corrects the article DOI: 10.1155/2016/4987831.].

Coronavirus Disease (COVID-19) Outbreak and Its Impact on Spinal Daily Practice : Preliminary Report from a Single (Regional) University Hospital in Republic of Korea.

OBJECTIVE: Since the first discovery of the 2019 novel coronavirus (COVID-19), rapid and wide spread of the disease has been reported and the World Health Organization announced that a 'pandemic' has started. Up to date there is little known regarding the impact of this outbreak on spinal specialists' daily clinical practice. We intended to evaluate how COVID-19 has affected the number of spinal disease patients we meet and operate in daily practice. METHODS: The de-identified data regarding number of patients visiting the spine clinic at a tertiary referral hospital and a secondary level hospital from January, February and March of 2017 to 2020 were retrospectively reviewed. The number of out-patient department (OPD) visits, number of emergency room (ER) visits as well as number of surgeries performed during the reviewed period were collected and analyzed, comparing 2020 to the previous 3 years. RESULTS: The number of daily OPD visits showed a steady decrease starting from January, and presented a statistically significant decrease by early March 2020, compared to the previous 3 years. During the same period, decrease in number of daily ER visits was statistically significant as well. The number of elective surgeries or number of surgeries for patients admitted via ER during COVID-19 outbreak remained similar to that of 2017-2019 suggesting, despite the decrease of patients visiting the hospital for spinal diseases, those whom required surgery still visited the hospital. The results were consistant among other hospital level. CONCLUSION: The outbreak of COVID-19 affected our daily practice as OPD and ER visits reduced but did not affect the number of surgeries. We believe that this report will be informative to spinal specialists worldwide fighting the COVID-19 pandemic.

Metallosis: A Complication in the Guided Growing Rod System Used in Treatment of Scoliosis.

Soft tissue reaction following metallic debris formation with the use of guided growing rod system has not been previously reported in human. The purpose of this study is to report complications caused by metallosis in a guided growing rod system. A 9-year-old female patient, who underwent treatment for the progressive idiopathic scoliosis (with Cobb's angle of 71°) with the guided growing rod system. Her Cobb's angle was corrected to 13° with the index surgery. During the 5 years postoperative period, she manifested recurrent episodes of skin irritation and progressive worsening of lateral curvature of the spine to an angle of 57°. Furthermore, at her final followup, Risser stage 4 with a gain in height of 26.4 cm was achieved. Considering adequate growth attainment and deterioration in the curvature, revision surgery with fusion was performed. Postoperative Cobb's angle of 23° was achieved with the final correction. During the revisional surgery, signs of implant wear and metallosis were observed at the location of the unconstrained screws. On histological evaluation, chronic inflammation with foreign body granules was seen. However, titanium level in the body was within normal range. She was discharged without any complications. More research on implant wear as a complication in the guided growing rod system is necessary before its widespread use. The occurrence of metallosis with the use of guided growing rod system in growing young children should be considered, when designing the implants.

The Analysis of Biomechanical Properties of Proximal Femur after Implant Removal.

Introduction. To compare the biomechanical stability of the femur following the removal of proximal femoral nail antirotation (PFNA-II) and dynamic hip screw (DHS). Material and Methods. 56 paired cadaveric femurs were used as experimental and control groups. In the experimental group, PFNA-II and DHS were randomly inserted into femurs on both sides and then removed. Thereafter, compression load was applied until fracture occurred; biomechanical stability of the femurs and associated fracture patterns were studied. Results. The ultimate load and stiffness of the control group were 6227.8 ± 1694.1 N and 990.5 ± 99.8 N/mm, respectively. These were significantly higher than experimental group (p = 0.014, <0.001) following the removal of PFNA-II (4085.6 ± 1628.03 N and 656.3 ± 155.3 N/mm) and DHS (4001.9 ± 1588.3 N and 656.3 ± 155.3 N/mm). No statistical differences in these values were found between the 2 device groups (p = 0.84, 0.71), regardless of age groups. However, fracture patterns were different between two devices, intertrochanteric and subtrochanteric fractures. Conclusions. Mechanical stability of the proximal femurs does not differ after the removal of 2 different of fixation devices regardless of the age. However, it was significantly lower compared to an intact femur. Different fracture patterns have been shown following the removal of different fixation devices as there are variations in the site of stress risers for individual implants.

Modification of tooth development by heat shock protein 60.

Although several heat shock proteins have been investigated in relation to tooth development, no available information is available about the spatial and temporal expression pattern of heat shock protein 60 (Hsp 60). To characterize Hsp 60 expression in the structures of the developing tooth germ, we used Western blotting, immunohistochemistry and in situ hybridization. Hsp 60 was present in high amounts in the inner and outer enamel epithelia, enamel knot (EK) and stratum intermedium (SI). Hsp 60 also appeared in odontoblasts beginning in the bell stage. To obtain data on the possible effect of Hsp 60 on isolated lower incisors from mice, we performed in vitro culturing. To investigate the effect of exogenous Hsp 60 on the cell cycle during culturing, we used the 5-bromo-2-deoxyuridine (BrdU) incorporation test on dental cells. Exogenously administered Hsp 60 caused bluntness at the apical part of the 16.5-day-old tooth germs, but it did not influence the proliferation rate of dental cells. We identified the expression of Hsp 60 in the developing tooth germ, which was present in high concentrations in the inner and outer enamel epithelia, EK, SI and odontoblasts. High concentration of exogenous Hsp 60 can cause abnormal morphology of the tooth germ, but it did not influence the proliferation rate of the dental cells. Our results suggest that increased levels of Hsp 60 may cause abnormalities in the morphological development of the tooth germ and support the data on the significance of Hsp during the developmental processes.

Evaluation of accuracy of plain radiography in determining the Risser stage and identification of common sources of errors.

BACKGROUND: Risser's sign is an established radiological marker for predicting growth potential in adolescent idiopathic scoliosis, but the accuracy of Risser's staging has been debated. This research was designed to evaluate the accuracy of Risser's staging and to identify causes of errors in Risser's staging. MATERIALS AND METHODS: Plain radiographs of 89 adolescent idiopathic scoliosis patients were evaluated for Risser's stage using both the Original and French methods. A three-dimensional computed tomography (3D-CT) was used to evaluate the accuracy of the plain radiographs. Inter- and intra-observer reliability of both methods was assessed on radiographs and 3D-CT images using weighted kappa statistics. The concordance rate for Risser's staging between plain radiographs and 3D-CT images were calculated. The various sources of staging differences between the two imaging methods were noted, grouped, and analyzed to identify common error patterns. RESULTS: Intra- and inter-observer staging reliabilities on plain radiography were 0.91 and 0.94, respectively, using the Original method and 0.91 and 0.92, respectively, using the French method. Intra- and inter-observer reliabilities on 3D-CT were 0.98 and 0.99, respectively, using the Original method and 0.97 and 0.99, respectively, using the French method. Mean concordance rates between plain radiography and 3D-CT were 59.76% and 67.42% using the Original and French methods, respectively. Common sources of error leading to misinterpretation of Risser's staging were miscalculation of apophysis excursion, skip ossification, isolated non-linear ossification, micro-fusion, and pseudo-fusion. CONCLUSIONS: Risser's staging by plain radiography is reliable but not accurate. Variations in the iliac apophysis ossification and misinterpretation of apophysis fusion are the main sources of error.