Introduction: The purpose of this study was to investigate whether PSTS before or immediately after extubation correlates more strongly with postoperative PSTS and would be a predictor of airway narrowing after extubation.

Methods: The subjects were 93 patients (18 males and 11 females; mean age, 63 years) who underwent anterior cervical spine surgery and adapted our hospital's perioperative management protocol. The PSTS was measured at each level from C2 to C5 on lateral cervical radiographs. Radiological measurements were performed preoperatively, before extubation on POD1 (Pre-ex), immediately after extubation on POD1 (Post-ex), 2 days after surgery (POD2), and 6 days after surgery (POD6). The rate of increase (ΔPSTS [%]) was measured at each postoperative period and level. Moreover, in POD2, laryngeal fiberscopy was performed. We examined (1) changes in ΔPSTS over time at each level, (2) the correlation coefficients between pre-ex and postoperative (POD2, POD6) ΔPSTS and post-ex and post-extubation (POD2, POD6) ΔPSTS, and (3) comparison between ΔPSTS and laryngeal fiberscopic findings at POD2.

Results: The temporal changes in ΔPSTS at each level (Pre-ex, Post-ex, POD2, POD6) were C2 (219±123, 190±73, 300±143, 202±87[%]), C3 (175±86, 195±73, 303±125, 237±90[%]), C4 (167±65, 191±68, 268±109, 227±78[%]), C5 (129±55, 140±57, 173±80, 157±65[%]). The ΔPSTS was higher in the upper cervical region, and the ΔPSTS was highest at POD2 at each level. The correlation coefficient between pre-ex ΔPSTS and postoperative ΔPSTS (POD2, POD6) was C2 level (0.31, 0.28), C3 level (0.41, 0.43), C4 (0.43, 0.47), C5 (0.72, 0.77), and between post-ex ΔPSTS and postoperative ΔPSTS (POD2, POD6) was C2 level (0.56, 0.47), C3 level (0.58, 0.52), C4 (0.61, 0.51), C5 (0.70, 0.70). Post-ex ΔPSTS at each level showed a moderate correlation with ΔPSTS at POD2 and 6 and a stronger correlation than pre-ex ΔPSTS. Patients with severe posterior pharyngeal wall swelling at laryngeal fiberscopy had significantly higher C2-4 levels in the mean ΔPSTS on POD2. There were no cases of airway obstruction or reintubation due to postoperative complications.

Conclusions: The results of this study showed that the PSTS immediately after extubation would be useful for predicting the deterioration of the PSTS after surgery, and evaluation of the PSTS immediately after extubation may help predict the occurrence of postoperative airway stenosis caused by the PSTS.

Introduction: In recent years, circumferential minimally invasive surgery (CMIS) using lateral lumbar interbody fusion (LLIF) and percutaneous pedicle screws (PPS) has been used for adult spinal deformity (ASD). It has gradually become popular. However, no clear standards indicate the extent to which CMIS can be applied to spinal deformities. In this study, we investigated the conditions for satisfying postoperative PI-LL <10° in CMIS.

Methods: The subjects were 145 patients with ASD who had undergone CMIS at our hospital since 2018 and were followed up for more than 2 years. The fixation range was from the lower thoracic vertebrae to the pelvis in all the cases. The mean age was 72.1 years, and the mean follow-up period was 54 months. The patients were divided into two groups: G group with PI-LL < 10° and P group with PI-LL ≥10° in the postoperative standing lateral view of the entire spine. Patient background, various parameters, Oswestry Disability Index (ODI), and low back pain/leg pain visual analogue scale (VAS) were compared. Furthermore, we investigated the risk factors for postoperative PI-LL ≥10° using a multivariate logistic analysis.

Results: There were no significant differences between the two groups in terms of age, gender, follow-up period, diameter and number of rods used, number of fused levels, number of LLIF procedures, surgical time, and blood loss. Postoperative low back pain VAS and postoperative ODI were significantly higher in group P. Regarding various parameters, preoperative PI, postoperative LL, preoperative/post-LLIF/postoperative PI-LL were significantly greater in the P group, and preoperative PT was significantly greater. Multivariate analysis showed that post-LLIF PI-LL was a factor for postoperative PI-LL ≥10°, with a cutoff value of 20°.

Conclusions: Post-LLIF PI-LL was detected as a risk factor for postoperative PI-LL ≥10° in CMIS for ASD, with a cutoff value of 20°.

Introduction: Lumbar spinal fusion surgery attempts to alleviate pain and neurological symptoms at the expense of spinal mobility. The collateral impact of increased spinal stiffness from fusion can impair functional activities of daily living (ADL). This study analyzed whether patients perceived a greater degree of lumbar stiffness-related disabilities postoperatively with an increasing number of fusion segments compared with their preoperative state.

Objective: We assessed the functional trade-off between the positive and negative impacts of fusion surgery on postoperative ADL in the patients.

Methods: This study included 189 patients who underwent lumbar spinal fusion surgery with more than 1 year of follow-up. We measured the limitations of preoperative and postoperative ADL using the Oswestry disability index (ODI) and the Lumbar Stiffness Disability Index (LSDI) developed by Hart et al. (2013).

Results: We categorized the patients into 5 groups according to the number of fusion segments: Group A with 1-level lumbar fusion for 45 cases; Group B with 2-level lumbar fusion for 33 cases; Group C with 3-level lumbar fusion for 38 cases; Group D with 4-level (i.e., L1-2 to L4-5) or 5-level fusion (i.e., L1-2 to L5-S1) for 34 cases; and Group E with long-segment fusion from the thoracic spine to the pelvis for 39 cases. The ODI scores in all groups, including group E, significantly (p < 0.0001) improved postoperatively. The LSDI scores significantly (p < 0.04) improved postoperatively in the 4 groups of A, B, C, and D, compared with the preoperative values, but the postoperative scores progressively worsened with increasing number of fusion segments from group A to D. In contrast, the LSDI scores in group E significantly (p < 0.0001) changed for the worse compared with the preoperative values.

Conclusions: Groups A to D showed a significant postoperative improvement in LSDI and ODI scores, which reflects the positive impact of the fusion surgery beyond its negative influence despite a progressively worse postoperative LSDI score with increasing number of fusion segments. Unlike the other 4 groups, group E with extensive fusion from the thoracic spine to the pelvis showed significantly worse postoperative LSDI score, although the ODI score in this group significantly improved. Spine surgeons need to know the adverse but unavoidable consequence of long-segment fusion from the thoracic spine to the pelvis, which deprives patients of spinopelvic mobility causing more disability more than the benefits it provides as a trade-off.

Introduction: Clinical outcomes, radiographic alignment, and complications of Oblique Lateral Interbody Fusion at L5/S1 (OLIF51) for degenerative diseases of the lumbosacral region and spinal deformities were investigated in 150 cases of spinal fusion surgery.

Methods: Among them, single-level fusion was performed in 55 cases and multi-level fusion in 95 cases, with an average number of fusion levels being 2.2 (range 1-5). The mean follow-up period was 46 months (range 13-86).

Results: The average surgical time and intraoperative blood loss per level were 112 minutes and 60 ml, respectively. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire demonstrated effective rates of 85% for pain and 82% for walking. The preoperative L5/S1 lordotic angle and disc height increased significantly from 10 degrees and 4 mm to 18 degrees and 5.7 mm at the follow-up. Fusion was achieved in 97% of the cases. No severe neurovascular complications were observed; however, instrumentation-related complications were noted in the deformity cases.

Conclusions: Lumbosacral fusion using OLIF51 was found to be useful because of its low invasiveness, high fusion rate, excellent lordotic correction, and power to reduce residual lower back pain. The application of this technique, particularly in cases of spinal deformity, allows for significant and harmonious lordotic correction in the lumbosacral region. Additionally, strategic lordotic correction of the lumbosacral region, considering pelvic incidence, is achievable even in short-segment fixation.

Introduction: Literature on good short-term results of intradiscal condoliase injection therapy for lumbar disc herniation are found. However, few reports have focused on its side effects. In this study, we examined the transition of Modic changes after intravertebral disc injection therapy with condoliase.

Methods: In total, 74 patients (48 males and 26 females), who were treated with condoliase injections and followed-up for >6 months, were enrolled in this prospective study. Their mean age was 46.8 years (range: 17-80 years). We investigated Visual Analog Scale (VAS) scores for low back pain and Oswestry disability index (ODI) as clinical assessments at preinjection, and 1, 3, and 6 months postinjection. Imaging evaluation was performed using MRI to examine disc height, Modic changes, and the progression of disc degeneration using Pfirrmann classification.

Results: The mean VAS score for low back pain notably improved from 5.2 preinjection to 2.2 postinjection, and ODI also improved from 39.0 to 14.5. The disc height decreased from 9.5 mm preinjection to 8.5 mm postinjection. Alteration of Modic changes was finally seen in seven cases, where newly type 1 appeared, and in five cases, where type 2 was changed to type 1. Progressive disc degeneration was observed in 41 cases. No significant difference was observed in the VAS for low back pain at either period despite the alteration of Modic changes, and a decrease in disc height or progression of disc degeneration at 6 months after injection were not significant factors of the alteration of Modic changes.

Conclusions: The alteration of Modic changes was observed in 12 patients (16%) at 6 months postinjection and did not correlate with a decrease in disc height or progression of disc degeneration. Although the lower back pain did not worsen despite the alteration of Modic changes, long-term follow-up will be necessary in the future.

Introduction: Considering the increasing number of spinal degenerative disorders, there is a need to shorten the length of hospital stay (LOS), and early identification of cases that deviate from the clinical pathway is crucial. This study aimed to investigate the relationship between early postoperative physical function and LOS and discharge home in patients postoperation with lumbar spinal stenosis (LSS).

Methods: The study participants included 288 postoperative patients with LSS. Clinical pathway at our hospital aimed to discharge patients on the 11th day after the operation. The administered survey items included questions regarding physical function on the third day after the operation, LOS, surgical information, and basic information. Moreover, patients were classified into two groups: those discharged on the 11th day postoperation (path-ENT group) and those discharged on the 12th day or later postoperation or transferred.

Results: Mean age of the patients was 71.2 years, 162 underwent fusion, and 96 underwent surgery for more than two vertebral segments. The path-ENT group comprised 169 patients. The results of logistic regression analysis adjusted for surgical information and basic attributes revealed that a decline in walking ability (odds ratio [OR] = 7.80, 95% confidence interval [CI: 3.20-19.00]) and sensory impairment (OR = 2.78, 95% CI: 1.49-5.17) were risk factors for failure to be discharged home within 11 days after surgery.

Conclusions: In our patients with LSS postoperation, early postoperative physical functions were associated with LOS and discharge home.

Introduction: The purpose of this study was to verify the reliability of a noninvasive digital camera sagittal vertical axis (SVA) and its relation to X-ray.

Methods: The subjects were six healthy subjects and eight patients with kyphosis. Digital camera SVA was taken in the upright position with markers attached to C7 spinous process and midpoints of superior and posterior iliac spines. The digital camera SVA was then calculated using Image J.

Statistical analysis was performed using intraclass correlation coefficient (ICC) and Spearman's rank correlation coefficient.

Results: For the digital camera SVA "taken from marker attachment" in six healthy subjects, ICC (1,1) = 0.83-0.84 and ICC (2,1) = 0.93-0.97. In eight patients with kyphosis, ICC (1,1) = 0.99 and ICC (2,1) = 0.99, as measured by Image J. The results of the "measurement with Image J" in eight patients with kyphosis showed that ICC (1,1) = 0.99 and ICC (2,1) = 0.99.

A moderate correlation was found between the digital camera SVA and SVA from standing full spine X-ray lateral images (rs = 0.86-0.90).

Conclusions: Digital camera SVA assessment had high intra- and interrater reliability and moderate correlation with X-ray. The digital camera SVA assessment is simple, noninvasive, and can be frequently performed, making the digital camera SVA assessment possible to track changes over time and to determine the effectiveness of physical therapy.

Introduction: In thoracolumbar/lumbar (TL/L) curve of Lenke types 1B and 1C, poor Cobb-angle correction is sometimes observed on the X-ray images after selective thoracic fusion, even when the hump shows good improvement. Our objective was to evaluate the relationship between postoperative improvement in the angle of trunk rotation (ATR) and Cobb angle of the TL/L curve.

Methods: Sixteen subjects (1 male and 15 females; mean age, 15.8 years) who underwent selective thoracic fusion for Lenke type 1B and 1C curves between 2009 and 2015 were followed up for ≥2 years. Improvement was analyzed for the correlation between the ATR measured by a scoliometer and Cobb angle measured on plain X-ray images preoperatively and at 2 years postoperatively. Cobb-angle improvement was predicted by regression analysis based on ATR improvement; Cobb-angle improvement was classified as poor or good when the actual improvement was less than or equal to the predicted value. Factors related to Cobb-angle improvement in the perioperative period were identified using logistic regression analysis.

Results: Moderate positive correlation was observed between the improvement in ATR and Cobb angle for TL/L curves at 2 years postoperatively (Pearson correlation coefficient 0.54, p = 0.02). Poor or good improvement in the Cobb angle was observed in eight cases each. The only perioperative factor that altered the effect of ATR improvement on Cobb-angle improvement was preoperative L4 tilt (odds ratio 0.58, p = 0.05). Significant effects were not observed for factors including body mass index, ATR or Cobb-angle improvement of the main thoracic curve, flexibility or apical vertebral translation of the preoperative TL/L curve, lumbar spine modifier, and thoracolumbar kyphotic angle. No domain of the Scoliosis Research Society questionnaire differed significantly between poor and good Cobb-angle improvements at 2 years.

Conclusions: ATR and Cobb-angle improvement in compensatory TL/L curves showed a correlation, and larger preoperative L4 tilt was related to better ATR but not Cobb-angle improvement. Larger preoperative L4 tilt might have a negative influence on the correction of frontal-plane curves but not on rotational deformity. Further investigation with a larger numbers of subjects is required.

Introduction: This study aimed to compare cases of spontaneous spinal epidural hematoma (SSEH) who underwent conservative treatment with those who underwent surgical treatment.

Methods: The targets of this study were 22 cases of SSEH comprising 8 males and 14 females. The average age was 72 years, and the average observation period was 247 days. Among these cases, 11 patients underwent conservative treatment and were placed in group C, while 11 patients underwent surgery and were placed in group O; comparisons were made between the groups.

Results: There were no significant differences in age, sex, and period from onset to hospital visit, presence of hemorrhagic diathesis, antithrombotic medication use, comorbidities, pain, Frankel Grade at the last observation, high location of hematoma, extent and location of hematoma, PT activity, PT-INR, PT time, and APTT. However, significant differences were observed in the initial Frankel grade, spinal canal hematoma occupation rate, and platelet counts.

Conclusions: SSEH cases that underwent surgical treatment exhibited significantly higher severity in terms of initial Frankel grade, higher spinal canal hematoma occupation rate, and lower platelet count compared to those who underwent conservative treatment. The cutoff value for platelet count was 163,000/μl.