Dural perforation and life-threatening central nervous system complications associated with septic arthritis of the lumbar facet joint: illustrative case
A 54-year-old woman had experienced the sudden onset of low-back pain while stooping down 6 days before and posterior neck pain 2 days before she was transported to the emergency department. The day before transport, she exhibited incoherent speech and appeared disoriented. The following day, she was transported to the emergency department with impaired consciousness and difficulty walking due to complete paralysis of the bilateral lower extremities. There was no history of primary disease, except for hypertension, and no invasive procedure had been performed on the lumbar spine. She presented with disorientation (Glasgow Coma Scale score of E3V2M6), neck stiffness, and paraplegia upon arrival. The initial blood test results revealed a white blood cell count of 35,370 cells/μL, C-reactive protein (CRP) of 39.21 mg/dL, and glucose from venous blood gas of 161 mg/dL. Computed tomography (CT) and magnetic resonance imaging (MRI) scans of the brain revealed hydrocephalus, cerebral edema, meningitis, and ventriculitis ( ). A lumbar puncture was performed immediately after finding these results along Jacoby’s line to analyze the cerebrospinal fluid (CSF), which suggested a diagnosis of BM ( ). The patient’s condition deteriorated rapidly, necessitating tracheal intubation and immediate external ventricular drainage, followed by acute treatment for meningitis, including intravenous administration of meropenem (6 g/day, 2 g every 8 hours) and vancomycin (3 g/day, 1 g every 8 hours), intraventricular administration of meropenem (20 mg/day) and vancomycin (10 mg/day), immunoglobulin therapy and dexamethasone administration for such a severe condition, management of increased intracranial pressure, and anticonvulsant therapy. Antibiotic treatments were administered after sampling all cultures, including the blood and CSF. When the drain was placed, cloudy CSF was identified, similar to that obtained via lumbar puncture ( ). Even after neurosurgical treatment, impaired consciousness did not improve. The patient’s eyes remained closed, and she did not respond to medical instructions while being intubated, despite light analgesia and sedation. Cardiac ultrasonography revealed neither cardiac dysfunction nor vegetation indicative of infectious endocarditis. Contrast-enhanced CT performed to identify the infection focus revealed a low-density area around the left L3–4 facet joint, without evidence of erosive or degenerative bone changes ( and B). Given this discovery, lumbar MRI was performed for the first time, which showed the facet joint abscess extending into both the paraspinal muscle and the epidural space. Sagittal short tau inversion recovery (STIR) MRI showed an epidural mass with high signal intensity compressing the dural sac and disruption of the dura mater at the L3–4 level. Axial STIR MRI revealed a mass with a high signal intensity, which represented pus in the left L3–4 facet joint, communicating with the intradural space ( and ). There were no MRI findings suggesting that the lumbar puncture passed through the facet joint and the abscesses. MRI of the cervical and thoracic vertebrae was also performed, and T2-weighted imaging showed an extensive high-signal lesion almost entirely below the level of T3 in the sagittal plane, indicating longitudinally extensive transverse myelitis (LETM; ). Hence, the patient was eventually diagnosed with septic arthritis of the left L3–4 facet joint, which caused BM with hydrocephalus, pyogenic ventriculitis, and acute transverse myelitis (ATM). Paraplegia was believed to have developed due to myelitis. After determining that antibiotic treatment alone was not effective, we decided to perform surgery 4 days after admission. A large paraspinal muscle abscess was detected on the left side. When the interlaminar space at L3–4 was reached, cloudy CSF mixed with the contents of the abscess flowed from that space to the left side ( Video 1 ). After a laminectomy at L3, the lesion had thickened with inflammatory dura mater, and a dural hole from which the peculiar CSF continued to leak was observed ( Video 2 ). This hole was larger than that typically observed after lumbar puncture. A space was seen below the dura mater, and the arachnoid mater appeared intact, beneath which the cauda equina was identified ( ). Thorough debridement of all contaminated tissues, including the facet capsule at the left L3–4 level, was performed, dural reconstruction was undertaken, and a tube for intra–soft tissue antibiotic perfusion (iSAP) was inserted. Stitches could not be used to repair this dural injury, so an autologous fat graft, SURGICEL powder (oxidized regenerated cellulose hemostat), and a mesh and glue technique were utilized for the reconstruction. VIDEO 1. Clip showing cloudy CSF flowing from the interlaminar space on the left side of L3–4. Click here to view. VIDEO 2. Clip showing CSF continuing to leak from the dural hole. Click here to view. Upon returning from surgery, the patient regained the ability to respond to instructions. iSAP was initiated with 120 mg gentamicin dissolved in 50 mL of normal saline at a flow rate of 2 mL/hr, and an additional intravenous injection of cefazolin (6 g/day, 2 g every 8 hours) was administered for septic arthritis. The patient’s condition gradually improved, enabling tracheal extubation 3 days postoperatively. The hydrocephalus observed on images also improved with time. External ventricular drainage and iSAP were completed 8 and 9 days after surgery, respectively. Following extubation, a dental examination revealed periodontitis that required treatment. Consequently, appropriate care was provided to address this issue. Additionally, it was determined that the patient had a 34-year smoking history that had commenced at the age of 20 years. All cultures from blood, CSF, and intraoperative abscesses were positive for methicillin-sensitive Staphylococcus aureus . Intraspinal administration of meropenem and vancomycin ended with removal of the ventricular drain. For BM with pyogenic ventriculitis, intravenous injections of meropenem and vancomycin were continued for 5 and 10 weeks, respectively, until MRI findings indicated that the ventricular abscess had resolved. Cefazoline was administered for 12 weeks to treat septic arthritis. Although the patient remained paraplegic with sensory disturbance from the trunk to the lower legs due to accompanying thoracic myelitis, complete consciousness was regained. The patient remains confined to a wheelchair but has the use of her upper extremities. There was no recurrence of infection 1 year after surgery. Informed Consent The necessary informed consent was obtained in this study. 

The necessary informed consent was obtained in this study. 

Observations The present case is extremely rare because the abscess generated by the SALFJ could have perforated the dura mater and played a key role in impairing the CNS. Surgical intervention for the lumbar lesions was effective in improving the consciousness disorder, which was attributable to proper debridement, reconstruction of the dura mater, and local irrigation with intravenous antibiotics. Patients with SALFJ are typically in their 6th decade of life, with a mean age of 55 (range 45–65) years, and no sex predominance. , – This infection typically affects older adults or immunocompromised patients, such as those with intravenous drug use, alcoholism, diabetes, end-stage renal failure, chronic liver disease, or malignant disease, and can cause serious morbidity. Nevertheless, cases in younger patients, those with a history of facet joint injections, and immunocompetent patients have been reported. , – The clinical presentation varies and includes back pain, fever, neurological abnormalities, and septic shock. Most patients (90%) present with back pain, while 50% are febrile. Notably, most cases show normal vital signs upon initial presentation. , The diagnosis can be challenging because of the atypical nature of the primary symptoms. The chief complaints can imitate urological or stomach issues caused by the abscess spreading to the psoas or erector spinae muscles, which can cause considerable therapeutic delays. , , , Because of the narrowness of the facet joint cavity, the abscess can spread either anteriorly, causing epidural spread, or posteriorly into the paraspinal muscles. Epidural abscess complicates 25% of cases, 38% of which have serious neurological deficits. The abscess can develop within 2 days to 5 weeks. , , The patient described in this report displayed characteristics typical of SALFJ. However, it was unique in that the epidural abscess might have perforated the dural sac. Only one other study has reported injury to the dura mater and intradural extension of the abscess, as in our case, although it did not state whether there was a hole in the dura mater. In our case, a hole in the dura mater was definitively identified, which may have resulted from cytokine interactions. A large abscess could have formed rapidly, once the infection was established. Consequently, the ventral facet capsule ruptured due to internal pressure and rapidly spread in both the epidural and paraspinal muscle spaces without any bone changes of the facet joint. Bacterial abscesses can produce inflammatory cytokines, the levels of which are influenced by the bacterial pathogen, symptom duration, and predisposing factors. Although the time to onset was not prolonged in this case and the patient was not immunocompromised, all cultures from her revealed S. aureus as the culprit pathogen. Inflammatory cytokines in S. aureus infections are associated with necrotic damage to the CNS. Based on these biological indicators and the patient’s abnormally high CRP level, it appears that interactions among cytokines on the surface of the dura mater might have caused a perforation, allowing pus to directly invade the CNS. Another significant aspect of this case is that the influx of the epidural abscess, generated by the SALFJ, resulted in the manifestation of BM complicated by hydrocephalus, pyogenic ventriculitis, and ATM. BM is a serious infectious condition characterized by meningeal infections and inflammation that causes significant morbidity and mortality. The most common symptoms are headaches, fever, a stiff neck, and altered mental status. Hydrocephalus is a serious intracranial issue that is frequently caused by BM, occurring in 5% of adult cases, which exacerbates the condition and is associated with a high fatality rate. Furthermore, pyogenic ventriculitis, an inflammation of the ventricles or periventricular region caused by infection, is also known to worsen the prognosis. Common causes of pyogenic ventriculitis include dissemination of meningitis into the ventricles, perforation of a brain abscess within the ventricles, neurosurgical procedures, and traumatic injuries to the brain. In this case, no brain abscess was identified from the onset, but the ventricular abscess had already been identified before external ventricular drain placement. Intraventricular drainage was not effective, but evacuation of the lumbar epidural abscess improved the condition. Considering these facts, it could be postulated that the direct invasion of the pus impeded normal CSF circulation, resulting in both hydrocephalus and pyogenic ventriculitis. This condition is associated with ATM. This myelitis is specifically classified as LETM, which is defined as a condition causing inflammation of the spinal cord extending over three or more vertebral segments. The thoracic segment is more frequently involved in these wide-range myelitis cases (82.2%) than in short myelitis cases (39.3%). S. aureus –related infectious myelitis has also been previously reported. Cytokines and chemokines play pivotal roles in neuroinflammation, neurodegeneration, and demyelination in BM. Thus, the LETM in this case was considered to be bacterial infectious myelitis following abscess intrusion. Although there was a hole in the dura mater, the arachnoid mater appeared normal during surgery. This finding indicates the existence of a space between the dura mater and the arachnoid mater. This space is usually filled with the dural border cell layer, which is an internally weak structure. Therefore, histological damage can easily disrupt it and create an unusual space. Since this layer closely interacts with the arachnoid layer below, it is likely that the abscess was able to destroy the tissue connections and enter the subarachnoid space somewhere from that space, even though the arachnoid mater seemed not to have ruptured at that location. S. aureus was reported to be responsible for SALFJ in 70% of cases, followed by Streptococcus spp., gram-negative rods, Enterococcus faecalis , and other organisms, accounting for 16%, 7%, 1%, and 5% of cases, respectively. In our case, S. aureus was isolated from all cultures. This organism establishes itself in the nasal passages, skin, and digestive system and often infiltrates the epidermis, soft tissues, and bloodstream. It is also a potential causative agent of various oral disorders. Although the mechanism by which these organisms develop SALFJ is unknown, its pathogenesis can be categorized into three distinct paths: the hematogenous process, direct inoculation of the facet joint, and transmission of infection from neighboring areas, such as the vertebral body, disc, or muscle. The hematogenous source is believed to be largely disseminated from a gastrointestinal, urinary, or dermatological focus. , However, the specific point of entry, such as chronic osteomyelitis, tooth abscess, or urinary infection, remains unidentified in approximately one-third of patients. Direct inoculation implies that mechanical tension on the facet joint could lead to the development of effusion or hemarthrosis, which in turn could facilitate bacterial growth. The infectious spread from nearby lesions is believed to be less common. , , The dental status of this patient, who was a smoker, was unfavorable, but there were neither degenerative findings of the facet joint nor complications with other spinal infections. Therefore, the possibility that the patient’s oral condition provided a hematogenous gateway for the SALFJ could not be excluded in this case. SALFJ is typically conservatively managed with antibiotic therapy. , Only in rare instances of neurological impairment or persistent infection after effective antibiotic treatment is surgical intervention warranted. , In our case, dural reconstruction and debridement were crucial. The dural suture was avoided because it was inappropriate for the infection. Therefore, a fat transplantation technique combined with the mesh-and-glue technique was selected, based on previous reports. , However, contaminated CSF from the ruptured area could potentially cause the reconstructed region to become detached. SURGICEL powder, an oxidized regenerated cellulose hemostat, has bactericidal properties against various bacteria, including S. aureus , and can produce a clot that robustly adheres to surrounding tissues. Hence, the clots generated with this hemostat were added to the surface of the fat graft on the side of the dura mater, and the graft was transplanted onto the ruptured lesion, followed by the application of polyglycolic acid meshes and the thrombin-fibrin polymer glue. Furthermore, the efficacy of continuous local antibiotic perfusion in the infected bone and soft tissue has been documented. The iSAP was effective as a local infection treatment for our patient, and the irrigated antibiotic had no adverse effects. This suggests that the dural reconstruction served not only as reinforcement but also in preventing the medication from inadvertently entering the intradural space. Various types of antibiotics were administered in this case, but this was unavoidable because it was necessary to select appropriate agents for each entity, comprising infections of the bone, soft tissue, and CNS. This approach was adopted because the tissue penetration of each antibiotic had to be considered, adhering to the proper recommended dosages, although there were no guidelines specific to SALFJ. Generally, first-generation cephalosporins are indicated for bone and soft tissue infections. However, it was necessary to prioritize treatment for BM to preserve the patient’s life. Consequently, empirical therapy was initiated with meropenem and vancomycin, which can effectively penetrate the CSF. Subsequently, cefazolin, which does not migrate to the CSF, was administered for SALFJ according to the operative findings. Intraventricular antibiotics were also administered because the patient had a very severe consciousness disorder. , Furthermore, determining the appropriate duration of antibiotic administration is crucial. The recommended treatment duration for SALFJ is approximately 6–8 weeks. , , In the case of vertebral osteomyelitis, the optimal duration should be tailored based on the specific risk of recurrence, such as an undrained abscess, wherein prolonged antibiotic treatment for more than 8 weeks can be beneficial. On the other hand, the optimal duration of treatment is unclear for BM complicated by pyogenic ventriculitis. According to the guidelines, 7–21 days or more is recommended in customary practice, whereas there are studies in which antibiotic therapy for BM lasted for 3 months. – In fact, the duration of meningitis therapy might need to be adjusted based on the patient’s clinical condition. , Therefore, we decided to continue antibiotic administration for BM until the findings of pyogenic ventriculitis improved and to keep treatment for SALFJ for more than 8 weeks based on the recommendation for vertebral osteomyelitis because we considered the presence of an undrained abscess. Lessons The potential for lumbar facet abscesses caused by SALFJ to disseminate bacterial clusters into the brain has not been previously described in the literature. This is a rare report indicating that SALFJ could perforate the dura mater and directly disturb the CNS. The patient developed BM, hydrocephalus, and pyogenic ventriculitis, along with ATM. Consciousness was fully recovered following surgical treatment at the lumbar level, which included thorough debridement, dural reconstruction, and iSAP, with appropriate antibiotics. This is an extremely meaningful case demonstrating that lumbar surgery contributed to saving the patient’s life. 

The present case is extremely rare because the abscess generated by the SALFJ could have perforated the dura mater and played a key role in impairing the CNS. Surgical intervention for the lumbar lesions was effective in improving the consciousness disorder, which was attributable to proper debridement, reconstruction of the dura mater, and local irrigation with intravenous antibiotics. Patients with SALFJ are typically in their 6th decade of life, with a mean age of 55 (range 45–65) years, and no sex predominance. , – This infection typically affects older adults or immunocompromised patients, such as those with intravenous drug use, alcoholism, diabetes, end-stage renal failure, chronic liver disease, or malignant disease, and can cause serious morbidity. Nevertheless, cases in younger patients, those with a history of facet joint injections, and immunocompetent patients have been reported. , – The clinical presentation varies and includes back pain, fever, neurological abnormalities, and septic shock. Most patients (90%) present with back pain, while 50% are febrile. Notably, most cases show normal vital signs upon initial presentation. , The diagnosis can be challenging because of the atypical nature of the primary symptoms. The chief complaints can imitate urological or stomach issues caused by the abscess spreading to the psoas or erector spinae muscles, which can cause considerable therapeutic delays. , , , Because of the narrowness of the facet joint cavity, the abscess can spread either anteriorly, causing epidural spread, or posteriorly into the paraspinal muscles. Epidural abscess complicates 25% of cases, 38% of which have serious neurological deficits. The abscess can develop within 2 days to 5 weeks. , , The patient described in this report displayed characteristics typical of SALFJ. However, it was unique in that the epidural abscess might have perforated the dural sac. Only one other study has reported injury to the dura mater and intradural extension of the abscess, as in our case, although it did not state whether there was a hole in the dura mater. In our case, a hole in the dura mater was definitively identified, which may have resulted from cytokine interactions. A large abscess could have formed rapidly, once the infection was established. Consequently, the ventral facet capsule ruptured due to internal pressure and rapidly spread in both the epidural and paraspinal muscle spaces without any bone changes of the facet joint. Bacterial abscesses can produce inflammatory cytokines, the levels of which are influenced by the bacterial pathogen, symptom duration, and predisposing factors. Although the time to onset was not prolonged in this case and the patient was not immunocompromised, all cultures from her revealed S. aureus as the culprit pathogen. Inflammatory cytokines in S. aureus infections are associated with necrotic damage to the CNS. Based on these biological indicators and the patient’s abnormally high CRP level, it appears that interactions among cytokines on the surface of the dura mater might have caused a perforation, allowing pus to directly invade the CNS. Another significant aspect of this case is that the influx of the epidural abscess, generated by the SALFJ, resulted in the manifestation of BM complicated by hydrocephalus, pyogenic ventriculitis, and ATM. BM is a serious infectious condition characterized by meningeal infections and inflammation that causes significant morbidity and mortality. The most common symptoms are headaches, fever, a stiff neck, and altered mental status. Hydrocephalus is a serious intracranial issue that is frequently caused by BM, occurring in 5% of adult cases, which exacerbates the condition and is associated with a high fatality rate. Furthermore, pyogenic ventriculitis, an inflammation of the ventricles or periventricular region caused by infection, is also known to worsen the prognosis. Common causes of pyogenic ventriculitis include dissemination of meningitis into the ventricles, perforation of a brain abscess within the ventricles, neurosurgical procedures, and traumatic injuries to the brain. In this case, no brain abscess was identified from the onset, but the ventricular abscess had already been identified before external ventricular drain placement. Intraventricular drainage was not effective, but evacuation of the lumbar epidural abscess improved the condition. Considering these facts, it could be postulated that the direct invasion of the pus impeded normal CSF circulation, resulting in both hydrocephalus and pyogenic ventriculitis. This condition is associated with ATM. This myelitis is specifically classified as LETM, which is defined as a condition causing inflammation of the spinal cord extending over three or more vertebral segments. The thoracic segment is more frequently involved in these wide-range myelitis cases (82.2%) than in short myelitis cases (39.3%). S. aureus –related infectious myelitis has also been previously reported. Cytokines and chemokines play pivotal roles in neuroinflammation, neurodegeneration, and demyelination in BM. Thus, the LETM in this case was considered to be bacterial infectious myelitis following abscess intrusion. Although there was a hole in the dura mater, the arachnoid mater appeared normal during surgery. This finding indicates the existence of a space between the dura mater and the arachnoid mater. This space is usually filled with the dural border cell layer, which is an internally weak structure. Therefore, histological damage can easily disrupt it and create an unusual space. Since this layer closely interacts with the arachnoid layer below, it is likely that the abscess was able to destroy the tissue connections and enter the subarachnoid space somewhere from that space, even though the arachnoid mater seemed not to have ruptured at that location. S. aureus was reported to be responsible for SALFJ in 70% of cases, followed by Streptococcus spp., gram-negative rods, Enterococcus faecalis , and other organisms, accounting for 16%, 7%, 1%, and 5% of cases, respectively. In our case, S. aureus was isolated from all cultures. This organism establishes itself in the nasal passages, skin, and digestive system and often infiltrates the epidermis, soft tissues, and bloodstream. It is also a potential causative agent of various oral disorders. Although the mechanism by which these organisms develop SALFJ is unknown, its pathogenesis can be categorized into three distinct paths: the hematogenous process, direct inoculation of the facet joint, and transmission of infection from neighboring areas, such as the vertebral body, disc, or muscle. The hematogenous source is believed to be largely disseminated from a gastrointestinal, urinary, or dermatological focus. , However, the specific point of entry, such as chronic osteomyelitis, tooth abscess, or urinary infection, remains unidentified in approximately one-third of patients. Direct inoculation implies that mechanical tension on the facet joint could lead to the development of effusion or hemarthrosis, which in turn could facilitate bacterial growth. The infectious spread from nearby lesions is believed to be less common. , , The dental status of this patient, who was a smoker, was unfavorable, but there were neither degenerative findings of the facet joint nor complications with other spinal infections. Therefore, the possibility that the patient’s oral condition provided a hematogenous gateway for the SALFJ could not be excluded in this case. SALFJ is typically conservatively managed with antibiotic therapy. , Only in rare instances of neurological impairment or persistent infection after effective antibiotic treatment is surgical intervention warranted. , In our case, dural reconstruction and debridement were crucial. The dural suture was avoided because it was inappropriate for the infection. Therefore, a fat transplantation technique combined with the mesh-and-glue technique was selected, based on previous reports. , However, contaminated CSF from the ruptured area could potentially cause the reconstructed region to become detached. SURGICEL powder, an oxidized regenerated cellulose hemostat, has bactericidal properties against various bacteria, including S. aureus , and can produce a clot that robustly adheres to surrounding tissues. Hence, the clots generated with this hemostat were added to the surface of the fat graft on the side of the dura mater, and the graft was transplanted onto the ruptured lesion, followed by the application of polyglycolic acid meshes and the thrombin-fibrin polymer glue. Furthermore, the efficacy of continuous local antibiotic perfusion in the infected bone and soft tissue has been documented. The iSAP was effective as a local infection treatment for our patient, and the irrigated antibiotic had no adverse effects. This suggests that the dural reconstruction served not only as reinforcement but also in preventing the medication from inadvertently entering the intradural space. Various types of antibiotics were administered in this case, but this was unavoidable because it was necessary to select appropriate agents for each entity, comprising infections of the bone, soft tissue, and CNS. This approach was adopted because the tissue penetration of each antibiotic had to be considered, adhering to the proper recommended dosages, although there were no guidelines specific to SALFJ. Generally, first-generation cephalosporins are indicated for bone and soft tissue infections. However, it was necessary to prioritize treatment for BM to preserve the patient’s life. Consequently, empirical therapy was initiated with meropenem and vancomycin, which can effectively penetrate the CSF. Subsequently, cefazolin, which does not migrate to the CSF, was administered for SALFJ according to the operative findings. Intraventricular antibiotics were also administered because the patient had a very severe consciousness disorder. , Furthermore, determining the appropriate duration of antibiotic administration is crucial. The recommended treatment duration for SALFJ is approximately 6–8 weeks. , , In the case of vertebral osteomyelitis, the optimal duration should be tailored based on the specific risk of recurrence, such as an undrained abscess, wherein prolonged antibiotic treatment for more than 8 weeks can be beneficial. On the other hand, the optimal duration of treatment is unclear for BM complicated by pyogenic ventriculitis. According to the guidelines, 7–21 days or more is recommended in customary practice, whereas there are studies in which antibiotic therapy for BM lasted for 3 months. – In fact, the duration of meningitis therapy might need to be adjusted based on the patient’s clinical condition. , Therefore, we decided to continue antibiotic administration for BM until the findings of pyogenic ventriculitis improved and to keep treatment for SALFJ for more than 8 weeks based on the recommendation for vertebral osteomyelitis because we considered the presence of an undrained abscess. 

The potential for lumbar facet abscesses caused by SALFJ to disseminate bacterial clusters into the brain has not been previously described in the literature. This is a rare report indicating that SALFJ could perforate the dura mater and directly disturb the CNS. The patient developed BM, hydrocephalus, and pyogenic ventriculitis, along with ATM. Consciousness was fully recovered following surgical treatment at the lumbar level, which included thorough debridement, dural reconstruction, and iSAP, with appropriate antibiotics. This is an extremely meaningful case demonstrating that lumbar surgery contributed to saving the patient’s life. 

We thank Editage for providing English-language editing of this paper. 

Dr. Itabashi reported personal fees from Daiichi Sankyo, Abbott Medical Japan, Bayer Japan, and Novartis Japan outside the submitted work. 

Conception and design: Yan, Taguchi, Doita. Acquisition of data: Yan, Taguchi, Chida, Y Suzuki, Shitogishi, Itabashi, Maeda. Analysis and interpretation of data: Yan, Yamabe. Drafting the article: Yan. Critically revising the article: Yan, Tsuda, Y Suzuki, M Suzuki, Chiba, Itabashi. Reviewed submitted version of manuscript: Murakami, Yan, Chida, Tsuda, Y Suzuki, Itabashi, Maeda. Approved the final version of the manuscript on behalf of all authors: Murakami. Administrative/technical/material support: Yan, Taguchi, Chida, Y Suzuki, Shitogishi. Study supervision: Murakami, Yamabe, Taguchi, Itabashi, Maeda, Doita. 

Videos Video 1 . https://vimeo.com/1031581287 . Video 2 . https://vimeo.com/1031583402 . 

Hideki Murakami: Iwate Medical University, Shiwa-gun, Iwate Prefecture, Japan. hmura1@icloud.com . 

