Takuya Taoka

Introduction: Guidelines published in 2013 recommend early closed reduction for cervical spine dislocation. There are two types of closed reduction: manual reduction and traction. Manual reduction can be performed early. In addition, it can correct rotation and requires a short time for complete reduction. We perform manual reduction for cervical spine dislocation. This study aimed to evaluate early manual reduction's success rate and safety for cervical dislocation. We also examined the relationship between time to reduction and improvement in paralysis.Methods: This retrospective cohort study included 361 patients with cervical spine injuries treated at our hospital between July 2010 and December 2021. We assigned patients to the early group if the time from injury to reduction was ≤6 hours and to the late group if >6 hours. We performed awake manual reduction on the patients. Furthermore, we compared reduction's success rate and safety, including neurological outcomes.Results: Overall, 46 patients were included in the study: 31 and 15 in the early and late groups, respectively. The success rate of reduction was 93%, and no neurological complications from reduction were observed. The neurological outcomes and reduction success rates were significantly superior in the early group than in the late group.Conclusions: Neurological outcomes were significantly superior when reduction was performed within 6 hours than after 6 hours. Manual reduction can be performed early, safely, and easily. It is effective for cervical spine dislocation requiring early reduction for an excellent neurologic prognosis.

Objectives and Background: To present a novel technique of treatment for a patient with basilar invagination. Basilar invagination (BI) is a congenital condition that can compress the cervicomedullary junction, leading to neurological deficits. Severe cases require surgical intervention, but there is debate over the choice of approach. The anterior approach allows direct decompression but carries high complication rates, while the posterior approach provides indirect decompression and offers good stability with fewer complications. Materials and Methods: A 15-year-old boy with severe myelopathy presented to our hospital with neck pain, bilateral upper limb muscle weakness, and hand numbness persisting for 4 years. Additionally, he experienced increased numbness and gait disturbance three months before his visit. On examination, he exhibited hyperreflexia in both upper and lower limbs, muscle weakness in the bilateral upper limbs (MMT 4), bilateral hypoesthesia below the elbow and in both legs, mild urinary and bowel incontinence, and a spastic gait. Radiographs revealed severe basilar invagination (BI). Preoperative images showed severe BI and that the spinal cord was severely compressed with odontoid process. Results: The patient underwent posterior surgery with the C-arm free technique. All screws including occipital screws were inserted into the adequate position under navigation guidance. Reduction was achieved with skull rotation and distraction. A follow-up at one year showed the following results: Manual muscle testing results and sensory function tests showed almost full recovery, with bilateral arm recovery (MMT 5) and smooth walking. The cervical Japanese Orthopedic Association score of the patient improved from 9/17 to 16/17. Postoperative images showed excellent spinal cord decompression, and no major or severe complications had occurred. Conclusions: Basilar invagination alongside Klippel–Feil syndrome represents a relatively uncommon condition. Utilizing a posterior approach for treating reducible BI with a C-arm-free technique proved to be a safe method in addressing severe myelopathy. This novel navigation technique yields excellent outcomes for patients with BI.

Background: Adult spinal deformity is a complex condition that causes lower back pain, causing spinal imbalance and discomfort in activities of daily life. After corrective spinal surgery, patients’ gait and balance abilities might not revert to normalcy and they might be at increased risk of falling. Therefore, early evaluation of such a risk is imperative to prevent further complications such as a fall, or even worse, fractures in post-surgery ASD patients. However, there has been no report of an investigation of such early changes in gait sway before and after ASD surgery. This is a prospective to investigate changes in gait sway before and following ASD surgery, using accelerometers, and also to examine motor function related to postoperative gait sway. Methods: Twenty patients were included who underwent corrective surgery as treatment for ASD, from October 2019 to January 2023. Measurement parameters included a 10 m walking test and the timed up-and-go test (TUG), gait sway was evaluated using accelerometers (root mean square; RMS), and hip flexion and knee extension muscle strength were tested. RMS included RMS vertical: RMS_V; RMS anterior posterior: RMS_AP; RMS medial lateral: RMS_ML. The radiographic spinopelvic parameters were also evaluated preoperatively and postoperatively. p < 0.05 was noted as remarkably significant. Results: Preoperative and postoperative RMS_V were 1.07 ± 0.6 and 1.31 ± 0.8, respectively (p < 0.05). RMS_ML significantly decreased from 0.33 ± 0.2 to 0.19 ± 0.1 postoperatively (p < 0.01). However, RMS_AP did not change postoperatively (0.20 ± 0.2 vs. 0.14 ± 0.1, p > 0.05). Patients’ one-month postoperative hip flexor muscle strength became significantly weaker (0.16 ± 0.04 vs. 0.10 ± 0.03 kgf/kg, p = 0.002), but TUG was maintained (11.6 ± 4.2 vs. 11.7 s, p = 0.305). RMS_V was negatively correlated with quadriceps muscle strength and positively with TUG. RMS_AP was negatively correlated with quadriceps muscle strength. All spinopelvic parameters became normal range after surgery. Conclusions: After corrective spinal fusion for ASD patients, the gait pattern improved significantly. Iliopsoas (hip flexor) and quadriceps femoris (knee extensor) muscles may play important roles for gait anterolateral and vertical swing, respectively.

Objectives: To investigate the outcomes of early balloon kyphoplasty (BKP) intervention compared with late intervention for osteoporotic vertebral fracture (OVF). Background: Osteoporotic vertebral fracture can lead to kyphotic deformity, severe back pain, depression, and disturbances in activities of daily living (ADL). Balloon kyphoplasty has been widely utilized to treat symptomatic OVFs and has proven to be a very effective surgical option for this condition. Furthermore, BKP is relatively a safe and effective method due to its reduced acrylic cement leakage and greater kyphosis correction. Materials and Methods: A retrospective cohort study was conducted at our hospital for patients who underwent BKP for osteoporotic vertebral fractures in the time frame between January 2020 and December 2022. Ninety-nine patients were included in this study, and they were classified into two groups: in total, 36 patients underwent early BKP intervention (EI) at Results: Adjacent segmental fractures were more frequently observed in the LI group compared to the EI group (33.3% vs. 13.9%, p = 0.034). There was a significant improvement in postoperative vertebral angles in both groups (p = 0.036). The cement volume injected was 7.42 mL in the EI, compared with 6.3 mL in the LI (p = 0.007). The mean surgery time was shorter in the EI, at 30.2 min, compared with 37.1 min for the LI, presenting a significant difference (p = 0.0004). There was no statistical difference in the pain visual analog scale (VAS) between the two groups (p = 0.711), and there was no statistical difference in cement leakage (p = 0.192). Conclusions/Level of Evidence: Early BKP for OVF treatment may achieve better outcomes and fewer adjacent segmental fractures than delayed intervention.

Study design: Technical note. Objectives: To present a new technique of treatment for a patient with thoracolumbar focal kyphosis due to osteoporotic verte-bral fracture (OVFs). Background : OVFs are common among the elderly population. Following a severe wedged fracture, patients often experience low back pain and disruptions in activities of daily living. Reconstruction surgeries, such as corpectomy, are among the treatment options for this condition. However, corpectomy requires longer surgical times and involves a significant amount of blood loss. Materials and Methods : An 80-year-old woman presented to our hospital with severe low back pain and gait disturbance. She had experienced an L2 OVF six years prior. Although she had no neurological deficit, she could not walk more than 200m due to pain. Preoperative spinal radiographs revealed severe sagittal malalignment, with the L2 vertebra collapsed and focal kyphosis of L1-3 measuring 34 degrees. Results: The patient underwent anterior and posterior surgery in the right decubitus position using a C-arm free technique. The surgical time was 133 minutes with an estimated blood loss of 100 ml. Hyperlordotic cages were inserted in the upper and lower disc space via a lateral approach, while percutaneous pedicle screws (PPS) were inserted from a posterior approach. These procedures were performed simultaneously under navigation guidance only. Post-operative images showed excellent spinal alignment, with local kyphosis reduced from 34 to 14 degrees, and no major or severe complications occurred. At one-year follow-up, the patient was able to walk smoothly, with her visual analogue scale for low back pain improving from 73mm to 13mm, and her Oswestry Disability Index improving from 53.3% to 13.3%. Conclusions/Level of Evidence : The simultaneous use of hyperlordotic cages and PPS is an effective and innovative navigation technique that yields promising outcomes for thoracolumbar focal kyphosis resulting from OVFs. This approach not only reduces surgical time but also minimizes intraoperative blood loss. Level V.

Study design: Retrospective cohort study. Objectives: To investigate the outcomes of early ballon kyphoplasty (BKP) intervention compared with late intervention for osteoporotic vertebral fracture. Background: Osteoporotic vertebral fractures, can lead to kyphotic deformity, severe back pain, depression, and disturbances in activities of daily living (ADL). BKP has been widely utilized to treat symptomatic OVFs and has proven to be a very effective surgical option for this condition. BKP is relatively a safe and effective method due to less acrylic cement leakage and greater kyphosis correction. Materials and Methods: A retrospective comparative study was conducted at our hospital for patients who underwent BKP for osteoporotic vertebral fractures in the time frame between January 2020 and December 2022. Ninety-nine patients were included in this study, patients were classified into two groups: 36 patients underwent early BKP intervention (EI)

Study design: Technical note. Objectives: To present a novel technique of treatment for patient with basilar invagination. Background : Basilar invagination (BI) is considered a congenital condition and can compress the cervicomedullary junction, causing neurologic deficit. Severe neurological deficit due to BI should be treated surgically. However, there is controversy regarding whether an anterior or posterior approach should be used. Anterior approach is optimal for decompression of cervicomedullary junction, but this approach has high complication rates. Posterior reduction has a high risk of occipital screws backout and/or instrument failure. Materials and Methods : A 15-year-old boy with severe myelopathy was referred to our hospital. He had neck pain, muscle weakness of bilateral upper limbs, gait disturbance appeared 3 months before he visited our hospital, he drops a cup several times recently. In the examination, he had hyperreflexia of upper and lower limbs and muscle weakness of bilateral arms (MMT 4), hypoesthesis was observed bilaterally below elbow and both legs. He also had clumsiness of bilateral hands, mild urinary and bowel incontinence, and spastic gait. His 10 second grip and release test was 16 in both hands. His grip power was 20 kg in right and 17 kg in left. Radiograms showed severe BI and spinal cord was severely compressed with odontoid process.. Results : The patinet underwent posterior surgery with C-arm free technique. All screws including occipital screws were inserted adequate position under navigation guidance. Reduction was achieved with skull rotation and distraction. A follow-up at one year we have these results : Manual muscle testing results and sensory function tests showed almost full recovery, bilateral arms (MMT 5) ,walking smoothly. Cervical Japanese orthopedic association score of the patient has improved from 9/17 to 16/17. Post-operative images showed an excellent spinal cord decompression, and no major or severe complications has occured . Conclusions/Level of Evidence : Basilar invagination with Klippel-Feil syndrome is relatively rare condition. Posterior approach and occipito-cervical fixation for BI treatment with navigation technique is a safe method to treat severe myelopaty with reducible odontoid. This novel navigation technique provides an excellent results for a patient with BI. Level V.

Study design :Technical note. Objectives : To present a new unilateral biportal endoscopic technique for lumbar disc herniation without C-arm . Background : Lumbar disc herniation requires surgical intervention when conservative methods fail. Shifts towards minimally invasive percutaneous endoscopic lumbar discectomy, including uniportal and biportal approaches, have been hindered by challenges such as steep learning curves and reliance on radiation-intensive C-arm guidance. Our study introduces the use of standard intraoperative navigation in unilateral biportal endoscopy (UBE) to reduce radiation exposure and increase surgical acuracy. Materials and Methods : A 24-year-old man with low back and bilateral leg pain with gait disturbance was referred to our hospital. He had have conservative treatment for 12 months in another hospital before admission. However, the conservative treatment did not work for him. He had low back pain (VAS 4/10) and bilateral leg pain (VAS 8/10), muscle waekness of bilateral legs (Manual muscle testing ;MMT of extensor hullusis longs 4 4), and numbness of bilateral lower leg. Preoperative lumbar MRI showed L4/5 large central disc herniation. Results: He underwent C-arm free unilateral biportal endoscopic discectomy under the guidance of O-arm navigation. The patient was successfully treated surgically. Postoperative lumbar MRI showed good decompression of dural sac and bilateral L5 nerve roots. MMT and sensory function of both leg had recovered fully on final follow-up at one year. Conclusions/Level of Evidence: The new unilateral biportal endoscopic technique under navigation guidance is useful technique for lumbar disc herniation. This innovative technique proved to be safe, accurate, and minimized radiation exposure for surgeons for the treatment of lumbar intervertebral disc herniation. Level V.

Background and Objectives: To present a new spinal shortening technique for tethered cord syndrome. Tethered cord syndrome (TCS) is a debilitating condition leading to progressive neurological decline. Surgical detethering for TCS is the gold standard of treatment. However, symptomatic retethering of TCS has been reported in 5%–50% of patients after initial release. To solve this problem, posterior spinal shortening osteotomy has been reported. This technique has risks of massive blood loss and neurological deterioration. The authors hereby report a new safe spinal shortening technique for tethered cord syndrome. Materials and Methods: A 31-year-old man with gait disturbance was referred to our hospital. After the delivery of treatment, he underwent surgical untethering of the spinal cord in another hospital. He had hyperreflexia of the Achilles tendon reflex and bilateral muscle weakness of the legs (MMT 3-4). He also had urinary and bowel incontinence, and total sensory loss below L5. An anteroposterior lumbar radiogram indicated partial laminectomy of L3 and L4. Lumbar MRI showed retethering of spinal cord. Results: The patient underwent a new spinal shortening technique for tethered cord syndrome under the guidance of O-arm navigation. First, from the anterior approach, disectomy from T12 to L3 was performed. Second, from the posterior approach, Ponte osteotomy was performed from T12 to L3, shortening the spinal column by 15 mm. The patient was successfully treated surgically. Postoperative lumbar MRI showed that the tension of the spinal cord was released. Manual muscle testing results and the sensory function of the left leg had recovered almost fully upon final follow-up at one year. Conclusions: A retethered spinal cord after initial untethering is difficult to treat. This new spinal shortening technique can represent another good option to release the tension of the spinal cord.

Background and Objectives: The implementation of intraoperative imaging in the procedures performed under the guidance of the same finds its history dating back to the early 1990s. This practice was abandoned due to many deficits and practicality. Later, fluoroscopy-dependent techniques were developed and have been used even in the present time, albeit with several disadvantages. With the recent advancement of several complex surgical techniques, which demand higher accuracy and are in conjunction with the existence of radiation exposure hazard, C-arm-free techniques were introduced. In this review study, we aim to demonstrate the various types of these techniques performed in our hospital. Materials and Methods: We have retrospectively analyzed and collected imaging data of C-arm-free, minimally invasive techniques performed in our hospital. The basic steps of the procedures are described, following with a discussion, along with the literature of findings, enlisting the merits and demerits. Results: MIS techniques of the thoracolumbar and lumbar spine that do not require the use of the C-arm can offer excellent results with high precision. However, several disadvantages may prevail in certain circumstances such as the navigation accuracy problem where in the possibility of perioperative complications comes a high morbidity rate. Conclusions: The accustomedness of performing these techniques requires a steep learning curve. The increase in accuracy and the decrease in radiation exposure in complex spinal surgery can overcome the burden hazards and can prove to be cost-effective.