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Meticulous clinical examination is essential for spinal disorders to utilize the diagnostic methods and technologies that strongly support physicians and enhance clinical practice. A significant change in the approach to diagnosing spinal disorders has occurred in the last three decades, which has enhanced a more nuanced understanding of spine pathology. Traditional radiographic methods such as conventional and functional X-rays and CT scans are still the first line in the diagnosis of spinal disorders due to their low cost and accessibility. As more advanced imaging technologies become increasingly available worldwide, there is a constantly increasing trend in MRI scans for detecting spinal pathologies and making treatment decisions. Not only do MRI scans have superior diagnostic capabilities, but they also assist surgeons in performing meticulous preoperative planning, making them currently the most widely used diagnostic tool for spinal disorders. Positron Emission Tomography (PET) can help detect inflammatory lesions, infections, and tumors. Other advanced diagnostic tools such as CT/MRI fusion image, Functional Magnetic Resonance Imaging (fMRI), Upright and Kinetic MRI, magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI), and diffusion tensor imaging (DTI) could play an important role when it comes to detecting more special pathologies. However, some technical difficulties in the daily praxis and their high costs act as obstacles to their further spread. Integrating artificial intelligence and advancements in data analytics and virtual reality promises to enhance spinal procedures’ precision, safety, and efficacy. As these technologies continue to develop, they will play a critical role in transforming spinal surgery. This paradigm shift emphasizes the importance of continuous innovation and adaptability in improving the diagnosis and treatment of spinal disorders.

Objective: Postoperative lymphopenia is reported as an excellent indicator to predict surgical-site infection (SSI) after spine surgery. However, there is still controversy concerning which serological markers can predict spinal SSI. This study aims to evaluate excellent and early indicators for detecting SSI, focusing on spine instrumented surgery. Materials and Methods: This study included 268 patients who underwent spinal instrumented surgery from January 2022 to December 2023 (159 female and 109 male, average 62.9 years). The SSI group included 20 patients, and the non-SSI group comprised 248 patients. Surgical time, intraoperative blood loss, and glycemic levels were measured in both groups. The complete blood cell counts, differential counts, albumin, and C-reactive protein (CRP) levels were measured pre-surgery and postoperative on Days 1, 3, and 7. In comparing the groups, the Mann–Whitney U test analysis was used for continuous variables, while the chi-squared test and Fisher’s exact test were used for dichotomous variables. Results: The incidence of SSI after spinal instrumentation was 7.46% and was relatively higher in scoliosis surgery. The SSI group had significantly longer surgical times (248 min vs. 180 min, p = 0.0004) and a higher intraoperative blood loss (772 mL vs. 372 mL, p < 0.0001) than the non-SSI group. In the SSI group, the Day 3 (10.5 ± 6.2% vs. 13.8 ± 6.0%, p = 0.012) and Day 7 (14.4 ± 4.8% vs. 18.8 ± 7.1%, p = 0.012) lymphocyte ratios were lower than the non-SSI group. Albumin levels on Day 1 in the SSI group were lower than in the non-SSI group (2.94 ± 0.30 mg/dL vs. 3.09 ± 0.38 mg/dL, p = 0.045). There is no difference in CRP and lymphocyte count between the two groups. Conclusions: SSI patients had lower lymphocyte percentages than non-SSI patients, which was a risk factor for SSI, with constant high inflammation. The Day 3 lymphocyte percentage may predict SSI after spinal instrumented surgery.

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.

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.

Abstract Background Symptomatic pseudarthrosis and cage migration/protrusion are difficult complications of transforaminal or posterior lumbar interbody fusion (TLIF/PLIF). If the patient experiences severe radicular symptoms due to cage protrusion, removal of the migrated cage is necessary. However, this procedure is sometimes very challenging because epidural adhesions and fibrous union can be present between the cage and vertebrae. We describe a novel classification and technique utilizing a navigated osteotome and the oblique lumbar interbody fusion at L5/S1 (OLIF51) technique to address this problem. Methods This retrospective study investigated consecutive patients with degenerative lumbar diseases who underwent TLIF/PLIF. Symptomatic cage migration was evaluated by direct examination, radiography, and/or computed tomography (CT) at 1, 3, 6, 12, and 24 months of follow-up. Cage migration/protrusion was defined as symptomatic cage protrusion > 5 mm from the posterior border of the over and underlying vertebral body compared with initial CT. We evaluated patient characteristics including body mass index, smoking history, fusion level, and cage type. A total of 113 patients underwent PLIF/TLIF (PLIF n = 30, TLIF n = 83), with a mean age of 71.1 years (range, 28–87 years). Mean duration of follow-up was 25 months (range, 12–47 months). Results Cage migration was identified in 5 of 113 patients (4.4%). All cases of symptomatic cage migration involved the L5/S1 level and the TLIF procedure. Risk factors for cage protrusion were age (younger), sex (male), and level (L5/S1). The mean duration to onset of cage protrusion was 3.2 months (range, 2–6 months). We applied a new classification for cage protrusion: type 1, only low back pain without new radicular symptoms; type 2, low back pain with minor radicular symptoms; or type 3, cauda equina syndrome and/or severe radicular symptoms. According to our classification, one patient was in type 1, three patients were in type 2, and one patient was in type 3. For all cases of cage migration, revision surgery was performed using a navigated high-speed burr and osteotome, and the patient in group 1 underwent additional PLIF without removal of the protruding cage. Three revision surgeries (group 2) involved removal of the protruding cage and PLIF, and one revision surgery (group 3) involved anterior removal of the cage and OLIF51 fusion. Conclusions The navigated high-speed burr, navigated osteotome, and OLIF51 technique appear very useful for removing a cage with fibrous union from the disc in patients with pseudarthrosis. This new technique makes revision surgery after cage migration much safer, and more effective. This technique also reduces the need for fluoroscopy.

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.

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: C-arm-free MIS techniques can offer significantly reduced rates of postoperative complications such as inadequate decompression, blood loss, and instrumentation misplacement. Another advantageous long-term aspect is the notably diminished exposure to radiation, which is known to cause malignant changes. This study emphasizes that, in some cases of spinal conditions that require a procedural intervention, C-arm-free MIS techniques hold stronger indications than open surgeries guided by image intensifiers. Materials and Methods: This study includes a retrospective analysis and review of various cervical and thoracic spinal procedures, performed in our hospital, applying C-arm-free techniques. The course of this study explains the basic steps of the procedures and demonstrates postoperative and intraoperative results. For anterior cervical surgery, we performed OPLL resection, while for posterior cervical surgery, we performed posterior fossa decompression for Chiari malformation, minimally invasive cervical pedicle screw fixation (MICEPS), and modified Goel technique with C1 lateral mass screw for atlantoaxial subluxation. Regarding the thoracic spine, we performed anterior correction for Lenke type 5 scoliosis and transdiscal screw fixation for diffuse idiopathic skeletal hyperostosis fractures. Results: C-arm-free techniques are safe procedures that provide precise and high-quality postoperative results by offering sufficient spine alignment and adequate decompression depending on the case. Navigation can offer significant assistance in the absence of normal anatomical landmarks, yet the surgeon should always appraise the quality of the information received from the software. Conclusions: Navigated C-arm-free techniques are safe and precise procedures implemented in the treatment of surgically demanding conditions. They can significantly increase accuracy while decreasing operative time. They represent the advancement in the field of spine surgery and are hailed as the future of the same.

Abstract Background In several previous studies, Charlson comorbidity index (CCI) score was associated with postoperative complications, mortality, and re-admission. There are few reports about the influence of CCI score on postoperative clinical outcome. The purpose of this study was to investigate the influence of comorbidities as calculated with CCI on postoperative clinical outcomes after PLIF. Methods Three hundred sixty-six patients who underwent an elective primary single-level PLIF were included. Postoperative clinical outcome was evaluated with the Japanese Orthopaedic Association lumbar score (JOA score). The correlation coefficient between the CCI score and postoperative improvement in JOA score was investigated. Patients were divided into three groups according to their CCI score (0, 1, and 2+). JOA improvement rate, length of stay (LOS), and direct cost were compared between each group. Postoperative complications were also investigated. Results There was a weak negative relationship between CCI score and JOA improvement rate (r = − 0.20). LOS and direct cost had almost no correlation with CCI score. The JOA improvement rate of group 0 and group 1 was significantly higher than group 2+. LOS and direct cost were also significantly different between group 0 and group 2+. There were 14 postoperative complications. Adverse postoperative complications were equivalently distributed in each group, and not associated with the number of comorbidities. Conclusions A higher CCI score leads to a poor postoperative outcome. The recovery rate of patients with two or more comorbidities was significantly higher than in patients without comorbidities. However, the CCI score did not influence LOS and increased direct costs. The surgeon must take into consideration the patient’s comorbidities when planning a surgical intervention in order to achieve a good clinical outcome.

Abstract Background Bertolotti’s syndrome is widely known to cause low back pain in young patients and must be considered as a differential diagnosis. Its treatment such as conservative therapy or surgery remains controversial. Surgical procedure is recommended for intractable low back pain. The three-dimensional (3D) lumbosacral transitional vertebrae anatomy should be completely understood for a successful surgery. Using an intraoperative 3D navigation and preoperative preliminary surgical planning with a patient-specific 3D plaster model contribute for safe surgery and good outcome. Case presentation A case of a 22-year-old Japanese male patient with intractable left low back pain due to lumbosacral transitional vertebrae with Bertolotti’s syndrome. The symptom resisted the conservative treatment, and anesthetic injection at pseudoarticulation only provided a short-term pain relief. Posterior resection using intraoperative three-dimensional (3D) navigation has been performed through microendoscopic view. Pseudoarticulation was totally and successfully resected in a safe manner. Conclusions Preoperative surgical planning and rehearsal using a patient-specific 3D plaster model was greatly useful and effective for surgeons in performing accurate and safe pseudoarticulation resection.

Background: Retro-odontoid pseudotumor (ROPT) is a non-neoplastic pathology of the craniovertebral junction that is usually associated with atlantoaxial instability. The mass compresses the spinal cord, causing cervical myelopathy and potentially resulting in severe disability. Posterior atlantoaxial fixation without laminectomy is a suitable surgical option when the symptoms are mild and the static compression is moderate. In the setting of patients with severe symptoms and large ROPTs, posterior decompression becomes necessary. However, achieving solid posterior atlantoaxial fusion is difficult without a bony surface, namely the C1 posterior arch. Here, we describe a novel technique of C1 laminoplasty to achieve C1 decompression, and posterior atlantoaxial fusion with a modified Goel technique. Methods: An 83-year-old man was referred to our orthopedic department with quadriplegia due to atlantoaxial instability. His daily life had been affected by severe neck pain, clumsiness of bilateral hands, and gait disturbance for more than 2 years. Preoperative cervical radiograms revealed atlantoaxial instability, and magnetic resonance imaging showed a large pseudotumor compressing to the spinal cord. Results: The patient underwent C1 laminoplasty to decompress the spinal cord and retain the posterior arch as a bony surface for grafting and posterior atlantoaxial fusion. The procedure was well tolerated. The patient’s quadriparesis was improved and his Japanese Orthopedic Association score improved from 9/17 to 15/17 and his visual analog scale score for neck pain improved from 75 mm to 28 mm at the 1-year follow-up. Conclusion: C1 laminoplasty and posterior atlantoaxial fusion appears useful when C1 decompression and atlantoaxial fusion become necessary.

Background: Adult spinal deformity (ASD) is caused by spinal malalignment and results in severe low back pain, neurological dysfunction, and severe deformity. Surgical treatment, such as long spinal fusion offers improved patient-reported outcomes compared to conservative treatment. However, surgical complication of proximal screw pullout represents a difficult problem in minimally invasive ASD surgery. We describe a novel technique to prevent screw pullout in ASD. Case presentation: A 71-year-old woman was referred to our hospital with severe low back pain and gait difficulty. Her daily life had been affected by severe lower back pain for more than 6 months. Standing radiograms indicated severe kyphoscoliosis. Two-stage minimally invasive corrective T10-to-pelvis fixation was performed. The first surgery was an L1–S1 image-guided oblique lumbar interbody fusion, with an operation time of 3 h 57 min and an estimated blood loss of 240 mL. After 1 week, the second percutaneous pedicle screw (PPS) fixation was performed and proximal screws were inserted under a transdiscal approach (T11) and with a lower angulation trajectory (T10) to enhance pullout strength. For this second surgery, operation time was 3 h 33 min, and estimated blood loss was 320 mL. No postoperative complications or neurological compromise was reported. In terms of clinical outcomes, Oswestry Disability Index improved from 56% to 24%, and visual analog scale score for lower back pain improved from 62 mm to 24 mm at the 1-year follow-up. Conclusions: Minimally invasive circumferential surgery with triangular fixation is effective for preventing proximal screw back-out and surgical invasiveness. With this new technique, surgeons and operating room staff can avoid the risk of adverse events due to intraoperative radiation exposure.

Background and Objectives: Adult spinal deformity (ASD) surgery, L5-S1 lordosis is very important factor. The main objective of the research is to retrospectively compare symptomatic presentation and radiological presentation in the sequelae of oblique lumbar inter-body spinal fusion at L5-S1 (OLIF51) and transforaminal lumbar interbody fusion (TLIF) for ASD. Materials and Methods: We retrospectively evaluated 54 patients who underwent corrective spinal fusion for ASD between October 2019 and January 2021. Thirteen patients underwent OLIF51 (average 74.6 years old, group O) and 41 patients underwent TLIF51 (average 70.5 years old, group T). Mean follow-up period was 23.9 months for group O and 28.9 months for group T, ranging from 12 to 43 months. Clinical and radiographic outcomes are assessed using values including visual analogue scale (VAS) for back pain and Oswestry disability index (ODI). Radiographic evaluation was also collected preoperatively and at 6, 12, and 24 months postoperatively. Results: Surgical time in group O was less than that in group T (356 min vs. 492 min, p = 0.003). However, intraoperative blood loss of both groups were not significantly different (1016 mL vs. 1252 mL, p = 0.274). Changes in VAS and ODI were similar in both groups. L5-S1 angle gain and L5-S1 height gain in group O were significantly better than those of group T (9.4° vs. 1.6°, p = 0.0001, 4.2 mm vs. 0.8 mm, p = 0.0002). Conclusions: Clinical outcomes were not significantly different in both groups, but surgical time in OLIF51 was significantly less than that in TLIF51. The radiographic outcomes showed that OLIF51 created more L5-S1 lordosis and L5-S1 disc height compared with TLIF 51.

Background: Indirect decompression for lumbar canal stenosis as a technique of minimally invasive surgery (MIS), is receiving considerable attention. Conventional MIS indirect decompression at L5-S1 is performed using intraoperative fluoroscopy. In this work, we describe a novel C-arm free simultaneous MIS indirect decompression technique for L5-S1 pathology. Methods: A 72-year-old woman with symptomatic L5 isthmic spondylolisthesis was referred to our hospital. The patient’s daily life had been affected by severe low back pain for 5 years and left leg pain for 2 years. The surgery was performed without C-arm fluoroscopy. The percutaneous pedicle screws and intervertebral cages were inserted only under navigation guidance in a single lateral position. Results: The patient was successfully treated with surgery. Her low back pain and left leg pain improved dramatically. Her clinical outcomes, the Oswestry disability index (ODI) improved from 48% to 14% and the low back pain visual analog scale (VAS) score improved from 78 mm to 23 mm at 1 year of final follow-up. Conclusions: C-arm-free simultaneous MIS indirect decompression for L5-S1 is a useful technique, which may reduce surgical time and blood loss. With this new technique, surgeons and operation room staff can avoid the risk of an adverse event of intraoperative radiation.

Background: Navigation surgery is becoming very popular for anterior cervical surgery. However, one difficult problem for anterior cervical surgery is setting the reference frame (RF), due to the lack of reliable structures. If the RF is attached to the head holder or operation table instead of the patient, the accuracy of navigation is not good. Materials and methods: This retrospective study included six patients who underwent anterior cervical surgeries with O-arm navigation. The RF was attached to the Caspar retractor using a special adaptor. Patients comprised three men and three women with a mean age of 62.8 years. Anterior cervical discectomy and fusion was performed in three cases, and anterior cervical corpectomy and fusion in three cases. We evaluated the accuracy of navigation, surgical time, intraoperative blood loss, complications, bony fusion, and clinical results. Results: Mean accuracy of anterior navigation was 1.1 ± 0.7 mm (range, 0–2 mm). Mean surgical time and blood loss were 166 ± 39 min (range, 121–359 min) and 280 ± 189 ml (range, 50–600 ml), respectively. Complications comprised one case of postoperative C5 palsy that recovered within 6 months. Mean Japanese Orthopedic Association (JOA) recovery rate was 52.4% (range, 20–100%). Adequate decompression and solid fusion were obtained in all cases. Conclusions: Intraoperative O-arm navigation-guided anterior cervical decompression and fusion is an effective technique for achieving precise decompression. This new navigation technique provides excellent results for severe cervical ossification of the posterior longitudinal ligament (OPLL) with minimum risk of adverse events from intraoperative radiation. We advocate the use of this novel technique in cases of cervical canal stenosis due to large disc osteophyte complex and OPLL, and also in cases of distorted cervical anatomy due to deformity, tumor, or revision surgery.

This is a prospective study that has been done to assess the lumbar sagittal alignment of patients positioned prone over an adjustable hinged carbon fiber operating table. The following three variations of table position have been considered: neutral, 20° convex, and 20° concave bending. A total of 33 patients who underwent lumbar disc herniation and lumbar canal stenosis surgery were enrolled. Patients who presented with spinal deformity akin to lumbar scoliosis or spondylolisthesis were excluded. For the surgical procedure, following the induction of endotracheal general anesthesia, patients were positioned prone on the adjustable hinged carbon fiber operating table. Radiographs of the lateral view of the lumbar spine were acquired for the three table positions, i.e., neutral, 20° convex, and 20° concave. The lumbar lordosis was measured on radiographs. The lumbar lordosis presented divergently in all three variations of the table (p < 0.01): 45.2 ± 11.0° in neutral; 52.0 ± 10.7° in 20° lumbar extension bending; and 35.9 ± 10.8° in 20° lumbar flexion bending. The efficacy of table bending was 46.5% in convex and 34.0% in concave bending. In conclusion, the lumbar lordosis in three different table positions were 35.9° in 20° convex bending, 45.2° in neutral, and 52.0° in concave bending. The efficacy of table bending was 46.5% in convex and 34.0% in concave bending.

Study design: Technical note. Objectives: To present a novel C-arm-free technique guided by navigation to insert and place a C1 lateral mass screw. Background and Objectives: Atlantoaxial subluxation (AAS) is a relatively common sequelae in patients with rheumatoid arthritis (RA) and upper cervical trauma. If they present with severe symptoms, surgical intervention such as posterior fusion is indicated. The established treatment for AAS is fixation with a C1 lateral mass screw and C2 pedicle screw (modified Goel technique) to achieve bony fusion. However, this technique requires fluoroscopy for C1 screw insertion. To avoid exposing the operating team to radiation, we present here a novel C-arm-free C1 lateral mass screw insertion technique for AAS. Materials and Methods: A 67-year-old man was referred to our hospital with neck pain, quadriparesis, and clumsiness and numbness of both upper and lower limbs. He had undergone C3–6 posterior fusion previously in another hospital. In physical examination, he had severe muscle weakness of bilateral upper limbs and hypoesthesia of all four limbs. He had hyper-reflexia of bilateral lower limbs and pollakiuria. His Japanese orthopedic score was 8 points out of 17. Preoperative radiograms showed AAS with an atlantodental interval (ADI) of 7 mm. MRI indicated retro-odontoid pseudotumor and severe spinal cord compression at the C1–2 level. The patient underwent posterior atlantoaxial fixation under navigation guidance. To prevent epidural bleeding during the insertion and placement of a C1 lateral mass screw, we have here defined a novel screw insertion technique. Results: The surgical time was clocked as 127 min and blood loss was 100 mL. There were no complications per-operatively or in the postoperative period. The patient showed almost full recovery (JOA 16/17) at two months follow-up and a solid bony fusion was noticed in the radiograms at one year follow-up. Conclusions: This novel surgical procedure and C1 lateral mas screw placement technique is a practical and safe method in recent advances of AAS treatment. Procedurally, the technique helps prevent epidural bleeding from the screw entry point and also allows for proper C1 screw insertion under navigation guidance without exposing surgeons and staff to the risk of fluoroscopic radiation.

Study design: Retrospective comparative study. Objective: Comparative study of C-arm free O-arm navigated minimally invasive cervical pedicle screw (MICEPS) fixation with conventional cervical pedicle screw fixation. Methods: Twenty-five patients with different cervical spine pathologies were operated with MICEPS with O-arm navigation (group M; 18 patients) and conventional pedicle screw (group C; 7 patients) from June 2017 to January 2020. Operative time, blood loss were recorded. Preoperative and postoperative radiograms, CT scans and MRI were evaluated. Postoperatively screw position accuracy and angulation was determined on CT. Breach rate was evaluated on CT scan and classified according to Neo grading. Complications if any were noted. Results: The average blood loss in group M and group C was 129 ml and 329 ml, respectively. The average operative time in group M and group C was 77.4 min and 82.3 min, respectively. A total of 148 screws were inserted. In group M, no patient showed grade 2 and 3 breach while in group C, grade 0 and 1 breach was found in 85.7% screws and grade 2 in 14.3% screws. Mean screw medial angulation was 45.2 degrees in group M and 33.4 degrees in group C. There was one dural tear and two C5 palsies in each group. Conclusion: With C -arm free O-arm navigated MICEPS fixation operative time and blood loss are less though not statistically significant. It has less pedicle breach rate, less incidence of neurovascular complications than conventional technique. There is no radiation exposure to operating surgeon and staff.

Background: Percutaneous pedicle screw (PPS) fixation as a minimally invasive surgery (MIS) is becoming the standard method for stabilizing thoracolumbar burst fractures. However, with the conventional PPS percutaneous reduction is difficult, and a great amount of usage of fluoroscopy is necessary. We describe a novel technique of C-arm free PPS with new reduction device for thoracolumbar fractures. Methods: A 22-year-old man presented to our hospital with severe low back pain and impending paraplegia secondary to T12 burst fracture. We performed short-segment fixation and reduction for this patent. The special PPS which have reduction mechanism were inserted under O-arm navigation guidance. The trauma reduction system was applied and the fracture was reduced without fluoroscopy. Results: Postoperative computed tomography (CT) showed the adequate screws position and complete reduction of the vertebral body. On one-year follow-up, the patient was asymptomatic, with the fracture healed and no implant loosening. Conclusions: C-arm free PPS and reduction is a useful MIS technique for thoracolumbar burst fractures.

Background and Objectives: Gait ability and spinal postural balance affect ADL in patients who underwent adult spinal deformity (ASD) surgery. However, it is still unclear how to determine what the cause is. This study was done to investigate various factors affecting gait, postural balance and activities of daily living (ADL) in patients who were operated on for ASD over a period of one year, following corrective surgery. Materials and Method: A cohort of 42 (2 men, 40 women, mean age, 71.1 years) who were operated on for ASD were included in this study. According to Oswestry Disability Index (ODI), based on their ADL, patients were segregated into satisfied and unsatisfied groups. Gait and postural balance abilities were evaluated before and after the operative procedure. Radiographs of spine and pelvis as well as the rehabilitation data (static balance, standing on single-leg; dynamic postural adaptation, timed up and go test (TUG); Gait Capability, walk velocity for a distance of 10 m) were acquired 12 months after surgery and analyzed. Spinopelvic parameters such as (lumbar lordosis (LL), pelvic tilt (PT), sagittal vertical axis (SVA), pelvic incidence (PI)) were marked and noted. The factors which affect patients’ satisfaction with their ADL were evaluated. Results: The ADL satisfied group included 18 patients (1 man, 17 women, mean age 68.6 years) and the unsatisfied group included 24 patients (1 man, 23 women, mean age 73.1 years). One year after the surgery, the two groups were tested. TUG (8.5 s vs. 12.8 s), 10 m walk velocity (1.26 m/s vs. 1.01 m/s), and single leg standing test (25 s vs. 12.8 s) were regarded as notably different. According to logistic regression analysis, only TUG was extracted as a significant factor. The cut-off value was 9.7 s, with sensitivity 75%, specificity 83%, area under the curve 0.824, and a 95% confidence interval of 0.695–0.953. Conclusions: A significant factor among all evaluations in postoperative ASD patients was TUG, for which the cut-off value for ADL satisfaction was 9.7 s.

Adult spinal deformity (ASD) is highly prevalent in persons older than 65 years, affecting more than 30% of the total population. There are many important reports that describe excellent postoperative results for ASD surgery. However, there is no report that describes a chronological evaluation of gait ability and spinal balance after ASD surgery. The present prospective study aimed to determine the recovery time of gait and spinal balance ability after adult spinal deformity (ASD) surgery. Patients with ASD (n = 25: mean age, 73.0 years) who underwent corrective surgery and preoperative and postoperative gait and spinal balance ability evaluation. Spinal radiographs and gait analysis data (static balance; single-leg standing, dynamic balance; time-up and go test, gait ability; 10 m walk velocity) were acquired preoperatively, 1 month, 6 months, and 12 months after surgery. The radiographic parameters of the spine and pelvis (lumbar lordosis; LL, pelvic tilt; PT, sagittal vertical axis; SVA, pelvic incidence; PI) were measured. The mean postoperative SVA, LL, PT, and PI-LL became 30.0 mm, 50.1 degrees, 14.1 degrees, and 0.35 degrees, respectively. Preoperatively, all spinal balance and gait ability were worse than the normal threshold (one-leg standing; 14.2 s vs. 15.0 s, time-up and go test; 13.9 s vs. 13.5 s, 10-m walk speed; 0.91 m/s vs. 1.00 m/s). At 12 months after surgery, all spinal balance and gait ability became normal or improved (single-leg standing; 14.7 s, time-up and go test; 11.0 s, 10-m walk speed; 1.09 m/s). The ODI at one-year follow-up improved from 46.8 ± 12.6% to 27.8 ± 18.1%. In conclusion, gait and spinal balance analysis revealed that ASD patients could not recover gait and spinal balance ability one month after surgery. At 12 months after surgery, gait ability and dynamic spinal balance became better than preoperative levels. However, the static spinal balance was at the same level as that of preoperative status.

Study design: Prospective study. Objective: The aim of this study is to visualize the morphology of a lumbar herniated disc and Kambin’s triangle in three dimensions (3D) based on preoperative CT/MRI fusion images. Methods: CT/MRI fusion images of 23 patients (10 males and 13 females; mean age 58.2 years) were used to evaluate Kambin’s triangle, which is created between the superior articular process (SAP), exiting nerve root (ENR), inferiorly by the superior endplate of the lower lumbar vertebra and dural canal medially at 60 degree and 45 degree endoscopic approach angles. The percentage of the safe usage of transforaminal endoscopic approach was evaluated to utilize a 5 mm dilater without partial facet resection in the fusion image. The 3D lumbar nerve root sleeve angulation (3DNRA), which is the angle between the axis of the thecal sac and the nerve root sleeve, was calculated. The herniated discs were also visualized in the CT/MRI fusion image. Results: The 3DNRA became smaller from L2 to S1. The L2 3DNRA was statistically larger than those of the other root, and the S1 3DNRA was significantly smaller than the others (p < 0.05). (L2, 41.0°; L3, 35.6°; L4, 36.4°; L5, 33.9°; and S1, 23.2°). The SAP-ENR distance at 60° was greatest at L4/5 (5.9 mm). Possible needle passages at 60° to each disc level were 89.1% at L2/3, 87.0% at L3/4 and 84.8% at L4/5. However, the safe 5 mm dilater passage at 60° without bony resection to each disc level were 8.7% at L2/3, 28.3% at L3/4 and 37.0% at L4/5. The 60° corridor at L2/3 was the narrowest (p < 0.01). All herniated discs were visualized in the fusion image and the root compression site was clearly demonstrated especially with foraminal/extraforaminal herniations. Conclusion: The 3D lumbar CT/MRI fusion image enabled a combined nerve-bony assessment of Kambin’s triangle and herniated disc. A fully endoscopic 5 mm dilater may retract the exiting nerve root in more than 60% of total cases. This new imaging technique could prove to be very useful for the safety of endoscopic lumbar disc surgery.

Background and Objectives: The thoracolumbar burst fracture is one of the most common spinal injuries. If the patient has severe symptoms, corpectomy is indicated. Currently, minimally invasive corpectomy with a navigated expandable vertebral cage is available thanks to spinal surgical technology. The aim of this study is to retrospectively compare clinical and radiographic outcomes of conventional and navigational minimally invasive corpectomy techniques. Materials and Methods: We retrospectively evaluated 21 patients who underwent thoracolumbar minimally invasive corpectomy between October 2016 and January 2021. Eleven patients had a navigated expandable cage (group N) and 10 patients had a conventional expandable cage (group C). Mean follow-up period was 31.9 months for group N and 34.7 months for group C, ranging from 12 to 42 months in both groups. Clinical and radiographic outcomes are assessed using values including visual analogue scale (VAS) for back pain and Oswestry disability index (ODI). This data was collected preoperatively and at 6, 12, and 24 months postoperatively. Results: Surgical time and intraoperative blood loss of both groups were not significantly different (234 min vs. 267 min, 656 mL vs. 786 mL). Changes in VAS and ODI were similar in both groups. However, lateral cage mal-position ratio in group N was lower than that of group C (relative risk 1.64, Odds ratio 4.5) and postoperative cage sinking was significantly lower in group N (p = 0.033). Conclusions: Clinical outcomes are not significantly different, but radiographic outcomes of lateral cage mal-position and postoperative cage sinking were significantly lower in the navigation group.

Background: Conventional L5 corpectomy requires a large incision and an extended period of intraoperative fluoroscopy. We describe herein a new L5 corpectomy technique. Methods: A 79-year-old woman was referred to our hospital for leg pain and lower back pain due to an L5 vertebral fracture. Her daily life had been affected by severe lower back pain and sciatica for more than 2 months. We initially performed simple decompression surgery, but this proved effective for only 10 months. Results: For revision surgery, the patient underwent minimally invasive L5 corpectomy with a navigated expandable cage without fluoroscopy. The second surgery took 215 min, and estimated blood loss was 750 mL. The revision surgery proved successful, and the patient could then walk using a cane. In terms of clinical outcomes, the Oswestry Disability Index improved from 66% to 24%, and the visual analog scale score for lower back pain improved from 84 to 31 mm at the 1-year follow-up. Conclusions: Minimally invasive L5 corpectomy with a navigated expandable vertebral cage is effective for reducing cage misplacement and surgical invasiveness. With this new technique, surgeons and operating room staff can avoid the risk of adverse events due to intraoperative radiation exposure.

Study design: Prospective study. Objective: Medical image fusion can provide information from multiple modalities in a single image. The present study aimed to determine whether three-dimensional (3D) lumbosacral vascular anatomy could be adequately portrayed using a non-enhanced CT–MRI medical image fusion technique. Summary of Background Data: Lateral lumbar interbody fusion has gained popularity for the surgical treatment of adult spinal deformity (ASD). Oblique lumbar interbody fusion at L5–S1 (OLIF51) is receiving considerable attention as a method of creating good L5–S1 lordosis. Access in OLIF51 requires evaluation of the vascular anatomy in the lumbosacral region. Conventional imaging modalities need a contrast medium to describe the vascular anatomy. Methods: Participants comprised 15 patients with ASD or degenerative lumbar disease who underwent corrective surgery at our hospital between January 2020 and June 2021. A 3D vascular image with bony structures was obtained by fusing results from MRI and CT. We processed the merged image and measured the distance between left and right common iliac arteries and veins at two levels: the lower end of the L5 vertebral body (Window A) and the upper end of the S1 vertebral body (Window B). Results: The mean sizes of Window A and Window B were 29.7 ± 10.7 mm and 36.9 ± 10.3 mm, respectively. The mean distance from the bifurcation to the lower end of the L5 vertebra was 23.7 ± 10.9 mm. Coronal deviation of the bifurcation was, from center to left, 12.6 ± 12.3 mm, and the distance from the center of the L5 vertebral body to the bifurcation was 0.79 ± 7.3 mm. Only one case showed a median sacral vein (6.7%). Clinically, we performed OLIF51 in 12 of the 15 cases (80%). Conclusion: Evaluating 3D lumbosacral vascular anatomy using a non-enhanced MRI and CT medical image fusion technique is very useful for OLIF51, particularly for patients in whom the use of contrast medium is contraindicated.

Study DesignLevel 4 retrospective review.PurposeBrace treatment is the standard nonoperative treatment for adolescent idiopathic scoliosis (AIS). Rotation correction is also important, because AIS involves a rotation deformity. The purpose of this study was to evaluate the impact of rotation correction after Osaka Medical College (OMC) brace treatment on clinical outcomes in AIS.Overview of LiteratureBrace treatment has a significant effect on the progression of AIS. However, few reports have examined rotation correction after brace treatment.MethodsA total of 46 patients who wore the OMC brace were retrospectively reviewed. The curve magnitude was determined according to the Cobb method, and the rotation angle of the apical vertebrae was measured by the modified Nash-Moe method. Based on the difference in the rotation angle before and after the initial brace treatment, patients were divided into two groups. Group A (n=33) was defined as no change or improvement of the rotation angle; group B (n=13) was defined as deterioration of the rotation angle. If the patients had curve or rotation progression of 5° or more at skeletal maturity, or had undergone surgery, the treatment was considered a failure.ResultsDifferences of rotation angle between before and after the initial brace treatment were 2°±2° in group A and –3°±2° in group B (p