Introduction: Introduction of procedures such as oblique lateral interbody fusion (OLIF25) and OLIF51 have led to significant advances in the domain of spine surgery. OLIF25 enables access to the L1-L5 intervertebral discs without splitting the psoas muscle, and OLIF51 provides access to the L5-S1 intervertebral discs. Despite being less invasive, reportedly, these approaches were associated with vascular injury in 3.6% of patients, and preventive measures are warranted.

Technical Note: Preoperative three-dimensional reconstructed computed tomographic images provide accurate visualization of the surgical approach, which may reduce the risk of vascular injury. However, in the event of such injury, prompt and accurate intervention is important to avoid fatality. In addition to a discussion regarding the role of preoperative imaging in vascular injury prevention, we discuss strategies for management of vascular injuries (both arterial and venous).

Conclusions: Preoperative imaging, as well as improved knowledge and skills for management of inadvertent intraoperative vascular injuries during OLIF are important for patient safety.

Introduction: We prospectively investigated the safety and bone fusion achieved with a new mini-titanium plate used for simple and firm fixation of a hydroxyapatite (HA) spacer for en-bloc cervical laminoplasty.

Methods: The study included the first nine consecutive patients (follow-up duration: 3-24 months, mean pre-Japanese Orthopaedic Association [JOA] score: 12.3 points). Computed tomography (CT) was performed 3, 6, 12, 18, and 24 months postoperatively. The ratio of bone fusion at the gutter, lateral mass, and lamina was measured at each level. We defined "partial fusion" as bone fusion observed in more than one slice and "complete fusion" as bone fusion observed in all slices.

Results: The mean improvement ratio in JOA scores was 68%, and no postoperative complications were observed. We used 25 plates and 75 screws in this study and observed no instrument failures. Partial fusion rates were 48, 79, 94, 92, and 83% at the gutter; 8, 16, 39, 58, and 50% at the lateral mass; and 8, 16, 39, 42, and 50% at the lamina. Complete fusion rates were 12, 58, 94, 92, and 83% at the gutter; 0, 0, 11, 17, and 33% at the lateral mass; and 0, 0, 11, 17, and 17% at the lamina.

Conclusion: A mini-titanium plate showed adequate safety. Bone fusion commenced at the gutter in approximately 50% of patients 3 months postoperatively and was completed in more than 90% of patients in 12 months and progressed gradually around the HA spacer.

Introduction: Diffuse idiopathic skeletal hyperostosis (DISH) is the spontaneous osseous fusion of the spine with anterior bridging osteophytes. Previous studies have reported that fractures in patients with DISH often lead to unstable fractures in fused segments, while stable fractures are more common in non-fused segments. In the present study, we focused on the positional relationship of the vertebral body and examined the intravertebral bone mineral density (BMD) of DISH using quantitative computed tomography (QCT).

Methods: The subjects were 20 patients in the DISH group and 32 patients in the control group who underwent bone mineral density evaluation by QCT. In the DISH group, BMD was assessed at the mid-height of the fused vertebral body, the lower end of the fused vertebral body, the lower end adjacent vertebral body, and the non-fused vertebral body, and in the control group, BMD was measured at the corresponding vertebral body height.

Results: BMD of the mid-height of the fused vertebral body and the non-fused vertebral body were significantly lower in the DISH group in the anterior region. On the other hand, there was no significant difference in BMD between the two groups in the lower end of the fused vertebral body and the adjacent vertebral body.

Conclusions: BMD loss in the anterior region in the mid-height of the fused vertebral body is considered to be affected by stress-sealing due to ligamentous ossification. In this study, anterior BMD loss was also observed in the non-fused vertebral body. Fractures of the non-fused vertebral body have been reported to be affected by the lever arm. However, no anterior BMD loss was observed in the lower end of the fused vertebral body and adjacent to the lower end, which is affected by the lever arm. Therefore, it is suggested that fractures in the non-fused vertebral body might be due to the influence of the lever arm and the anterior BMD loss.

Introduction: Anterior decompression and fusion are the mainstay of surgical methods for thoracic disc herniation (TDH), but recent improvements in surgical techniques and other advances have enabled the use of the posterior approach. The surgical outcomes of posterior surgery for TDH in our hospital were investigated.

Patients and Methods: For TDH, patients with a large hernia, or patients with malalignment, conserved disc height, and instability at the affected level are treated with posterior thoracic interbody fusion (PTIF), and with posterolateral fusion (PLF) if the hernia is small, without instability. The study subjects were eight patients (six men, two women) who underwent posterior surgery for TDH in our hospital from January 2018 to May 2021.

Results: The mean age at surgery was 64.6 years, and the hernia level was T10/11 in four, T11/12 in one, and T12/L1 in three patients. PTIF was conducted in three patients and PLF in five patients. Improved gait function and reduced pain were observed postoperatively in all the patients. Their JOA scores also significantly improved, with a mean improvement rate of 52.8%. There were no perioperative complications.

Conclusions: PLF can be performed as posterior surgery for TDH if the hernia can be safely removed posteriorly, but PTIF should be selected for hernias of large sizes. Overall, the treatment outcomes in the present study were good.

Purpose: We investigated the factors that cause poor postoperative segmental lordosis (SL) acquisition in minimally invasive spinal fusion using anterior column realignment (ACR), extreme lateral interbody fusion (XLIF), and percutaneous pedicle screws (PPS) in patients with adult spinal deformity (ASD).

Methods: Seventy-four ASD patients underwent correction surgery with ACR, XLIF, and PPS between 2018 and 2020 and were followed up for more than 12 months. We examined the surgical level, fused range, preoperative disc condition, SL, anterior disc height (ADH), posterior disc height (PDH), cage lordotic angle, cage height, and spinopelvic parameters. The patients were divided into two groups for comparison. The first group consisted of postoperative SL of segment underwent ACR <17° (Group P). The other group consisted of postoperative SL ≥ 17° (Group G). We classified disc condition into six types using computed tomography: the less-degenerative type with lordosis (type N), less-degenerative type with kyphosis (type K), unilateral degeneration type (type U), disc-cavity disappearance type (type D), anterior-degeneration type (type A), and posterior-degeneration type (type P).

Results: There were no significant differences in the age, gender, cage lordotic angle, cage height, cage position, and spinopelvic parameters. Pre- and postoperative SL was significantly lower and preoperative PDH was higher in group P than in group P. Disc types A was significantly higher in group P. Logistic regression analysis was performed with postoperative SL < 17° as the dependent variable. Preoperative PDH and, preoperative SL were detected as risk factors. ROC analysis revealed that the preoperative SL was 4° (AUC 0.76), and the preoperative PDH cutoff value was 3.7 mm (AUC 0.78).

Conclusions: Factors causing poor SL acquisition were investigated in patients who underwent correction surgery using ACR, XLIF, and PPS. High preoperative PDH and low preoperative SL were risk factors for poor postoperative SL in the segment undergoing ACR.

Introduction: We report dynamic stabilization with vertebroplasty for thoracolumbar osteoporotic vertebral fractures (OVF).

Materials: Twenty patients that underwent this method were included. We investigated surgical invasion, bone union, change of ROM, and shortening of the segment before and after surgery, and the changes in ADL.

Results: The average operation time was 117.9 minutes and blood loss was 31 ml. Bone fusion was obtained in 11 out of 12 cases on follow-up of more than 1 year. The shortening was 5.1 mm, and the ROM decreased from 18.9 days preoperative to 6.1 days follow-up. ADL improved in all the cases.

Conclusions: This method was a effective minimally invasive method for OVF.

Introduction: Although much research has focused on the degree of stability necessary for unstable degenerative lumbar spinal disease, results remain inconclusive. Rigid fusion can achieve a high degree of stability, and decompression alone may not provide adequate stability.

Methods: The study included 24 patients who underwent non-fusion stabilisation using the Segmental Spinal Correction System (SSCS); 15 patients presented with lumbar spinal canal stenosis, 5 with degenerative spondylolisthesis, and 4 with disc herniation.

Results: The Japanese Orthopaedic Association score improved from 14.4 to 25.1. The mean range of motion of the stabilised segment decreased from 9.2 to 3.7 at final follow-up. The operated segment was fused in 7 patients. We observed no recurrence at the stabilised segment, and no patient underwent additional surgery.

Conclusions: SSCS was associated with favourable outcomes for treatment of unstable degenerative lumbar spinal disease in the middle term period and may serve as a useful alternative to intervertebral fusion and decompression alone.

Spinous process-splitting laminectomy for thoracic and lumbar lesions is followed by implantation of screws a few millimetres lateral to the bilateral edge of the laminectomy. A hydroxyapatite (HA) spacer is threaded using a nylon thread, which is passed through the screws and tied to secure the laminae in place.

The study included five patients (aged 42-72 years) who underwent surgery using this technique.

We used one spacer in one, two spacers in three, and three spacers in one patient.

Postoperative computed tomography revealed good outcomes following this technique, without breakage of laminae and screw back-out.

This method led to a shorter interval between dural suture placement and completion of the operation.

To date, HA spacers were threaded through holes created in the opened laminae and were fixed using nylon threads; however, fixation of nylon threads to the opened lateral laminae was often challenging. The aforementioned technique enables easy and firm fixation of HA spacers with minimal exposure and without any injury to the laminae.

Introduction: Fixation of burst fractures of the thoracolumbar spine using the Percutaneous Pedicle Screw (PPS) has been used with good results. In our hospital, we use the side loading system and the top loading system devices.

Methods: The purpose of this study is to clarify the surgical outcomes of thoracolumbar rupture fractures by using different devices.

Among 287 cases of thoracolumbar spine injury, 55 cases that met the criteria were included. Radiological parameters were measured at preoperative, postoperative, and follow-up CT scans, and compared between the side loading system (S group) and the top loading system (T group).

Result: There was no significant difference in the correction of Anterior Vertebral Height (AVH), Posterior Vertebral Height (PVH), Vertebral Body Angle (VBA), and Canal Occupying Ratio (COR) at postoperative and follow-up. The S group was significantly better in the correction of Local Kyphotic Angle (LKA) at postoperative and follow-up (p< 0.05).

Conclusion: The side loading system is not originally a PPS system and the procedure is rather complicated, but it may have a strong corrective power. It is important to select an implant from the viewpoint of necessary corrective force and minimally invasive.

Purpose: We investigated the factors associated with cage subsidence (CS) in segments treated with anterior column realignment (ACR) in patients who underwent minimally invasive spinal fusion using ACR, extreme lateral interbody fusion (XLIF), and percutaneous pedicle screw (PPS) placement for management of adult spinal deformity (ASD).

Methods: The study included 42 patients with ASD, who underwent surgical correction using ACR, XLIF, and PPS between 2018 and 2020 and were followed up for >12 months. Patients were categorised into the cage subsidence group (Group CS, 13 patients) and the non-cage subsidence group (Group NCS, 29 patients). We recorded the surgical level, range of fusion, segmental lordosis (SL), anterior disc height (ADH), posterior disc height, cage lordotic angle, anterior and posterior cage heights, cage position, and spinopelvic parameters.

Results: The mean age was higher and posterior cage height was significantly lower in Group CS. A significantly larger number of patients used 30° cages and had an anterior cage position. Postoperative pelvic incidence-lumbar lordosis was higher and SL and ADH were lower in Group CS. Logistic regression analysis using CS as the dependent variable showed that use of the 30° cage was a risk factor for CS.

Conclusions: We investigated factors associated with CS in segments treated with ACR and also the optimal cage position in patients who underwent surgical correction using ACR, XLIF, and PPS. We observed that placement of a 20° lordotic cage at the centre of the vertebral body may prevent CS and achieve good lordosis.

Introduction: Myelomeningocele (MMC) is a common neural tube defect. Skin closure for MMC repair is challenging, and the surgical approach remains controversial, particularly in cases of MMC accompanied by severe kyphosis and large skin defects. We describe MMC in a newborn and discuss the surgical procedure of skin closure in this patient.

Case Report: A full-term female neonate born by caesarean delivery was diagnosed with hydrocephalus on fetal ultrasonography at 28 weeks of gestation and was referred to our hospital. Fetal magnetic resonance imaging revealed MMC at the thoracolumbar region, gibbus apex, cerebellar deformity, and hydrocephalus. She was born by caesarean delivery at 38 weeks' gestation and weighed 2,892 g with head circumference of 34.5 cm (+1.1 standard deviation) at birth. Clinically, she presented with MMC measuring 50×62 mm in size, bilateral club feet, and severe spinal kyphosis. No other congenital anomalies were detected, and she underwent MMC closure surgery at 2 days of age. Based on the extent of kyphosis and skin defect, we concluded that the skin defect did not need skin flap closure. After closure of the neural duct, we performed U-shaped sutures for skin closure. The skin was retracted using U-shaped sutures thrice intermittently and was closed during a single operative procedure. The patient showed no complications associated with wound closure, 6 months postoperatively.

Conclusions: U-shaped sutures used for MMC skin closure ensure complete preservation of the subcutaneous tissue without massive blood loss or invasion, which serves as an advantage of this approach, particularly in newborns with vulnerable skin. U-shaped sutures may be useful for closure of skin defects >50 mm in size, without major operative complications. We report the case of a neonate with MMC who underwent successful skin closure using U-shaped sutures.

Introduction: A sequestrated lumbar disc hernia in the dorsal epidural space is extremely rare. We report a case of a huge lumber disc hernia in the dorsal epidural space.

Case report: A 65-year-old man. The patient developed sudden gait disturbance due to muscle weakness and pain in both lower extremities. A dorsal epidural lesion located from the L2 upper endplate to the L3 lower endplate was identified in MR imaging. The signal intensity of this lesion was low to iso in T1 and slightly high in T2. Preoperatively, the suspected diagnosis was spinal epidural hematoma; however, the intra- and post-operative diagnosis was sequestrated disc hernia. Sequestrated disc hernia on the dorsal side of dural sac has been reported to occur more frequently in the upper lumber level compared with the usual disc hernia. Although a precise preoperative diagnosis is often difficult, a marginal enhanced effect on Gd contrast-enhanced MR imaging could help to differentiate epidural hematoma from a tumor.

Conclusions: We should consider sequestrated hernia as one of the differential diagnoses for a dorsal epidural lesion in the upper lumber level.

Osteoid osteoma often occurs in young men under the age of 20 and appears in many long trunk bones. It does not grow larger than 15 mm in diameter. Prostaglandin materials related to osteoid osteoma induces local tissue edema even in small osteomas. We describe the case of a 17-year-old woman who presented with cervical pain and radiculopathy due to osteoid osteoma close to the cervical pedicle. We opted for surgical treatment to treat her symptoms. Open surgery was performed under CT guidance for the safe and correct removal of tumor, because a less invasive ablation technique under CT or MRI guidance may injure surrounding nerves and vessels.

Introduction: We report a rare case of ectopic cerebrospinal fluid (CSF) pooling that developed after idiopathic spinal cord herniation (ISCH) surgery.

Case Report: A 57-year-old man presented with Brown-Séquard syndrome. Magnetic resonance imaging (MRI) revealed ISCH at the T4/5 level.

Intraoperatively, we observed herniation of the spinal cord into an intramural pouch between the duplicated ventral dura mater. We released and repaired the hernia using an expanded polytetrafluoroethylene (ePTFE) sheet. The patient's symptoms worsened by the 7^th month postoperatively, and MRI revealed ectopic CSF pooling at the ventral aspect of the spinal canal from the cervical to lumbar levels. During re-operation, we identified a wide cavity through the dural defect. Intraoperative findings confirmed extension of the pre-existing intramural pouch that encompassed all spinal levels.

Conclusions: Membranous adhesion secondary to an ePTFE sheet may function as a one-way valve on the pulsatile CSF and result in the aforementioned complication.

Introduction: We report a case of a diffuse idiopathic skeletal hyperostosis (DISH) -induced vertebral fracture in an elderly patient who was treated using percutaneous reduction.

Case Report: An 83-year-old man presented with an L1 fracture showing anteroposterior displacement and paralysis (Frankel B class) accompanied by DISH. We inserted a percutaneous screw using the penetrating endplate screw (PES) method with the patient placed in the prone position. The rod was adjusted based on the appropriate reduction position and was fixed to the screw initially at the caudal aspect. The screw at the cranial aspect was gradually pulled toward the rod by fixing it. Reduction was successful without screw loosening. Paralysis recovered to Frankel class C1 postoperatively, and no screw loosening was observed one year later.

Conclusion: Percutaneous reduction is advantageous for low invasion and bone fusion. The PES method may be a useful treatment option in patients with the aforementioned clinical presentation.

Introduction: We report two cases of thoracic pyogenic spondylitis with rapidly worsening myelopathy due to epidural abscess, and two cases of spinal fusion with transpedicular arch drainage for rapid decompression of the spinal cord and rapid control of the infected lesion in patients with pulmonary pyogenic disease and periaortic inflammation.

Case Report: Case 1. A 62-year-old man. The patient developed sudden gait disturbance due to muscle weakness in both lower extremities, and bladder and bowel dysfunction. MR imaging of the thoracic spine showed evidence of pyogenic spondylitis and epidural abscess at the Th7-8 level causing significant spinal cord compression. A laminectomy was performed on Th6-8, and transpedicular drainage was inserted into the Th7/8 discs from the root of the Th8, and PPS fixation was performed on Th5, 6-10, and 11. The patient's lower extremity muscle strength gradually improved, and he was able to walk unaided one year after the surgery.

Case 2. A 61-year-old woman. A diagnosis of pyogenic spondylitis of Th4/5 was made and antibiotics were started. CT chest on the 5th day of hospitalization showed a pyogenic right lung and inflammation around the aorta, and surgery was performed on the 11th day. The lesion was fixed with PPS at Th 2, 3-6, and 7 on one side without deployment deeper than the muscle layer.

On the non-deployed side, transpedicular drainage was percutaneously placed from the Th5 root to the Th4/5 discs. The inflammatory response gradually improved after the surgery, and the patients' symptoms disappeared without further exacerbation.

Conclusion: The procedure performed in this case was considered to be effective for immediate decompression of the spinal cord and rapid drainage of the infected area.

Introduction: We report a simple, inexpensive, and excellent novel method for surgical hemostasis in epidural bleeding.

Technical note: An AbiteneR sheet type (0.8 g) was mixed with 1 bottle of thrombin solution (5,000 units) and 10 ml of saline, and the mixed solution was prepared by lightly stirring and filled in a syringe with a 14 G intravenous catheter and sprayed on the bleeding site. If you put surgical cotton on it and suck it, you can stop the bleeding quickly and easily without pressure.

Conclusions: This method has the same excellent hemostatic properties as the SurgifloR, however, it is significantly cheaper.