Background
This study aims to assess the clinical and radiographic outcomes of biportal endoscopic lumbar discectomy compared to microscopic lumbar discectomy in obese patients with lumbar herniated discs. Previous research has established a positive correlation between operation time and estimated blood loss in obese patients undergoing microscopic lumbar discectomy, based on an increase in body mass index. However, no studies have specifically examined the outcomes of biportal endoscopic lumbar discectomy in this patient population. Therefore, this study seeks to fill this research gap and provide valuable insights into the effectiveness of these two surgical approaches for obese patients with lumbar herniated discs.
Methods
This retrospective multicenter study analyzed and compared clinical and radiological data from 48 obese patients with a body mass index (BMI) greater than 30 kg/m² who underwent either microscopic or biportal endoscopic lumbar discectomy. The study assessed clinical outcomes using the visual analog scale (VAS), Oswestry Disability Index (ODI), and EuroQol-5D (EQ-5D) scores. Radiological data were obtained through magnetic resonance imaging (MRI) scans.
Results
The study included a total of 48 patients, with 31 patients undergoing microscopic discectomy and 17 patients undergoing biportal endoscopic discectomy. Both groups showed improvements in VAS, ODI, and EQ-5D scores following surgery compared to preoperative scores. However, there was no significant difference in these outcome measures between the two surgical techniques. Although there was a no significant difference in the occurrence of recurrent disc herniation confirmed by postoperative MRI, there was significant difference in the number of patients requiring additional surgery between the two groups.
Conclusions
For obese patients with lumbar disc herniation that did not respond to conservative treatment, this study found no significant differences in clinical or radiological outcomes between microscopic and biportal endoscopic surgery methods. However, it is worth noting that the biportal group had a lower incidence of reoperation compared to the microscopic group.

Objective
Proximal junctional fracture (PJFx) at the uppermost instrumented vertebra (UIV) or UIV+1 is the most common mechanism of PJF. There are few studies assessing the radiographic progression after PJFx development. Therefore, this study sought to identify the risk factors for radiographic progression of PJFx in surgical treatment for ASD.
Methods
In this retrospective study, among 317 patients aged > 60 years who underwent ≥5-level fusion from the sacrum, 76 with PJFx development were included. According to the change in proximal junctional angle (PJA), two groups were created: Group P (change ≥10°) and Group NP (change <10°). Patient, surgical, and radiographic variables were compared between the groups to demonstrate risk factors for PJFx progression using uni- and multivariate analysis. The receiver operating characteristic (ROC) curve was used to calculate cutoff values. Clinical outcomes, such as visual analog scale (VAS) scores for back and leg pain, the Oswestry Disability Index (ODI) score, and the Scoliosis Research Society (SRS)-22 score, and revision rate were compared between the two groups.
Results
The mean age at the index surgery was 71.1 years, and there were 67 women enrolled in the study (88.2%). There were 45 patients in Group P and 31 in Group NP. A mean increase of PJA was 15.6° (from 23.2° to 38.8°) in Group P and 3.7° (from 17.2° to 20.9°) in Group NP. The clinical outcomes were significantly better in Group NP than Group P, including back VAS score, ODI value, and the SRS-22 scores for all items. Revision rate was significantly greater in group P than in group NP (17.8% vs. 51.6%, p=0.001). Multivariate analysis revealed that overcorrection relative to the age-adjusted ideal pelvic incidence (PI)–lumbar lordosis (LL) target at the index surgery (odds ratio [OR]=4.484, p=0.030], PJA at the time of PJFx identification (OR=1.097, p=0.009), fracture at UIV versus UIV+1 (OR =3.410, p=0.027) were significant risk factors for PJFx progression. The cutoff value of PJA for PJFx progression was calculated as 21° using the ROC curve.
Conclusions
The risk factors for further progression of PJFx were overcorrection relative to age-adjusted PI–LL target at the index surgery, PJA > 21° at initial presentation, and fracture at the UIV level. Close monitoring is warranted for such patients not to miss the timely revision surgery.

Purpose
The biplanar whole body imaging system (EOS) is a new tool for measuring whole body sagittal alignment in a limited space. This tool may affect the sagittal balance of patients compared to conventional whole spine radiography (WSX). This study is to investigate the difference in sagittal alignment between WSX and EOS.
Materials and Methods
We compared spinal and pelvic sagittal parameters in 80 patients who underwent EOS and WSX within one month between July 2018 and September 2019.The patients were divided based on sagittally balanced and imbalanced groups according to pelvic tilt (PT) >20˚, pelvic incidence-lumbar lordosis >10°, C7-sagittal vertical axis (SVA) > 50 mm in WSX.
Results
In sagitally imbalanced group, for WSX versus EOS, the pelvic parameters demonstrated compensation in EOS with smaller PT (27.4±11.6° vs. 24.9±10.9°, p=0.003), greater sacral slope (SS), and patients tended to stand more upright with smaller C7-SVA (58.4±17 mm vs. 48.9±57.3 mm, p=0.003), T1-pelvic angle (TPA), T5-T12, and T2-T12. However, in sagitally balanced group, these differences were less pronounced only with smaller PT (10.8±6.9° vs. 9.4±4.7°, p=0.04), TPA and T2-T12 angle, but SS and C7-SVA were similar (p>0.05).
Conclusions
EOS shows a negative SVA shift and lesser pelvic tilt than WSX especially in patients with sagittal imbalance. When making a surgical plan, surgeon should consider these differences between EOS and WSX.

After posterior cervical arthrodesis, many problems can arise, including adjacent segment degeneration and the related adjacent segment disease (ASD). As indicated by studies on the causes of ASD, posterior cervical arthrodesis can produce biomechanical and kinematic changes in adjacent unfused segments due to inappropriate forces. Several studies have been conducted to determine the appropriate lowest instrumented vertebra, specifically regarding whether to cross the cervicothoracic junction via extension of long-segment posterior cervical fusion. We searched for relevant articles in electronic databases including PubMed, the Cochrane Registry, Embase, and Ovid. Five meta-analyses were reviewed on this topic. Among these, Goyal et al. (2019), Rajjoub et al. (2022), and Chang et al. (2022) argued that ending instrumentation at the cervical level was associated with higher rates of ASD and reoperation. However, Truumees et al. (2022) and Coban et al. (2022) found no statistically significant differences between cases of instrumentation ending at the cervical and thoracic levels in the rates of ASD and requirement of revision surgery. Cervicothoracic junction breakage is a known possibility after cervical spine surgery because of the anatomical fragility of the junction. Terminating at the thoracic level reduces the stress on the cervicothoracic junction, thereby decreasing complications such as cervicothoracic junction breakage and lowering the frequency of reoperation. Based on the findings published to date, instrumentation across the cervicothoracic junction can be reasonably recommended in cases of multilevel posterior cervical fusion based on the lower reoperation and higher fusion rate.