Asian Spine Journal最新文献

Study design: Retrospective observational study.

Purpose: To evaluate the effectiveness of the inlet view in detecting anterior deviations of the S2 alar iliac (S2AI) screw during spinopelvic surgery and to assess the utility of the obturator inlet (OI) and iliac oblique (IO) views as alternative imaging methods.

Overview of literature: S2AI screws are increasingly utilized in spinopelvic fixation due to their biomechanical advantages. However, malpositioning of screws can lead to neurovascular complications. While inlet views in fluoroscopic techniques are generally effective for identifying screw deviations, there are instances where deviations go unnoticed.

Methods: We analyzed data from 101 patients who underwent spinopelvic surgery involving 202 S2AI screws. Postoperative computed tomography (CT) images were reviewed to identify screw deviations. The reconstructed fluoroscopic views from CT, including the inlet, OI, and IO views, were assessed for their effectiveness in detecting deviations. An experimental study using pelvic bone models simulated scenarios where deviations were undetectable in the inlet view but visible in the OI view.

Results: Screw deviations were identified in 12 cases (11.9%) and 13 screws (6.4%), including six screws (3.0%) with anterior deviations and seven screws (3.5%) with posterior deviations. The accurate inlet view detected anterior deviations in three of the five cases analyzed with reconstructed images. However, two cases of anterior deviation were missed due to an insufficient inlet view caused by a 30° caudal tilting angle. In contrast, the OI view successfully identified all cases of both anterior and posterior deviations. In particular, deviations above the arcuate line of the pelvic brim were not detectable in the inlet view.

Conclusions: The inlet view alone is inadequate for detecting anterior deviations, especially those located above the arcuate line of the pelvis. The OI and IO views demonstrated greater effectiveness in identifying deviations, thereby enhancing the accuracy and safety of S2AI screw placement.

Study design: Observational cadaveric anatomical study.

Purpose: To investigate the anatomical relationship between the segmental vessels and the diaphragmatic crus, aiming to reduce the risk of segmental vessel injury.

Overview of literature: Total en bloc spondylectomy and lateral lumbar interbody fusion are advanced surgical procedures associated with segmental vessel injury. Previous research suggests these injuries may arise from anatomical variations where segmental vessels intersect intervertebral discs. At upper lumbar levels, the diaphragmatic crus lies adjacent to the vertebral bodies, and its relationship with segmental vessels may increase vascular risk. Although this proximity has been noted, no study has specifically examined the detailed anatomy of the crus in relation to segmental vessels. Clarifying this relationship is critical for surgical planning and safety.

Methods: Fifteen Thiel-embalmed human cadavers (three males, 12 females; mean age 90.1 years) were dissected. Segmental arteries and veins from L1 to L5 and both crura were identified and measured. Crus origin, width, and distance from the vertebral midline were assessed. Data were analyzed using paired t-tests and Wilcoxon signed-rank tests.

Results: The right crus was broader, originated more caudally, and was positioned closer to the vertebral midline along the ventral surface of the vertebral body than the left crus, especially at L1-L3. Segmental arteries and the left segmental vein coursed between the crus and vertebral bodies, whereas the right segmental vein consistently passed ventral to the crus.

Conclusions: The diaphragmatic crus shows laterality in origin, width, and position, with distinct relationships to segmental vessels. Recognizing these anatomical features may help surgeons minimize vascular injury and improve safety during lumbar spinal surgery.

Endoscopic transforaminal lumbar interbody fusion (TLIF) offers substantial advantages in the management of degenerative spinal diseases, including accelerated postoperative recovery. However, its technical complexity and steep learning curve pose risks for nerve root injury. Optimizing nerve root protection in full-endoscopic facet-sparing TLIF (FE fs-TLIF) and full-endoscopic facet-resecting TLIF (FE fr-TLIF) is essential for enhancing surgical safety. This study aimed to improve the nerve root protection in FE fs-TLIF and FE fr-TLIF by optimizing cage glider selection and insertion techniques based on the specific cage shape-banana-shaped or bullet-shaped. The goal was to ensure safe cage positioning and mitigate nerve root injury during discectomy, endplate preparation, and cage insertion. These strategies were validated through cadaveric simulations and clinical implementation. In FE fr-TLIF utilizing bullet-shaped (straight) cages, one-tip and two-tip cage gliders effectively protected the traversing nerve root by facilitating medial cage entry, thereby minimizing irritation of the exiting nerve root. Conversely, in FE fr-TLIF with banana-shaped cages, the lateral tilt of the cage holder during implantation required the use of a two-tip cage glider to protect the traversing and exiting nerve roots, thereby mitigating the potential risk of nerve irritation. In FE fs-TLIF, a one-tip cage glider is preferred for safeguarding the exiting nerve root, while the traversing root is inherently protected by the medial wall of the facet joint. The use of a two-tip cage glider in FE fs-TLIF can cause injury to the nerve root during glider insertion. In addition to the selection of cage gliders, improper cage insertion steps can also contribute to postoperative neurapraxia. The appropriate selection of cage gliders with corresponding insertion techniques is critical for nerve root protection in endoscopic TLIF. Tailoring these choices to the specific approach (FE fs-TLIF or FE fr-TLIF) and cage type (banana or bullet) enhances surgical safety and clinical outcomes.

Study design: Prospective observational radiographic study.

Purpose: To evaluate how different car seat recline angles affect global spinal alignment and lap belt positioning in healthy adults, and to assess the influence of demographic factors on these changes.

Overview of literature: Seated posture alters global spinal alignment and may contribute to spinal symptoms, especially in individuals with adult spinal deformity (ASD) or following spine surgery. However, radiographic data on reclined seated postures and their impact on spinal alignment and restraint safety remain limited.

Methods: Lateral radiographs were obtained from 100 healthy adults in standing and seated postures at 25°, 35°, and 45° recline angles. Spinal parameters (cervical lordosis, thoracic kyphosis, thoracolumbar kyphosis, lumbar lordosis, sacral slope, pelvic tilt, and T1 spinopelvic inclination) and seat belt metrics (X-value, Z-value, and lap belt angle) were measured. Multivariate regression was used to assess associations with sex, age, height, and body mass index (BMI).

Results: Reclining reduced cervical/lumbar lordosis and sacral slope, while thoracic kyphosis and pelvic tilt increased. Higher BMI was associated with a cranially shifted and more horizontal lap belt. Taller individuals showed greater T1 spinopelvic inclination and pelvic parameters. Females exhibited more pronounced thoracic kyphosis and pelvic retroversion across reclining angles.

Conclusions: Car seat recline significantly alters spinal alignment and seat belt positioning, with changes influenced by age, height, and BMI. These findings support ergonomic improvements in seat design and may inform surgical planning for ASD.

Study design: Randomized, double-blind, placebo-controlled trial.

Purpose: To evaluate the efficacy and safety of inhaled methoxyflurane for pain relief during transforaminal epidural steroid injection (TFESI) in patients with lumbar radiculopathy.

Overview of literature: TFESI is a common intervention for lumbar radiculopathy, but procedural pain remains a concern. Methoxyflurane is a rapid-onset, inhaled analgesic with a favorable safety profile. While its effectiveness in procedural pain relief has been demonstrated in other medical settings, its role in TFESI remains underexplored.

Methods: Sixty patients undergoing TFESI were randomized to receive inhaled methoxyflurane or placebo before the procedure. Pain intensity was assessed using the Visual Analog Scale (VAS) at multiple time points during and after TFESI. Secondary outcomes included patient and physician satisfaction, as well as the incidence of adverse events. Renal and hepatic function parameters were evaluated pre- and post-procedure to assess safety.

Results: The methoxyflurane group reported significantly lower worst pain scores during TFESI compared to placebo (3.33±0.70 vs. 5.71±1.23, p <0.01), with sustained pain relief for up to 60 minutes post-procedure. Adverse events in the methoxyflurane group were mild and self-limiting (dizziness, nausea/vomiting, and dry mouth), occurring in 10% of patients. No significant between-group differences were observed in renal or hepatic function indices. Patient satisfaction was significantly higher with methoxyflurane (96.67%) than with placebo.

Conclusions: Inhaled methoxyflurane is a safe and effective analgesic for TFESI, offering significant procedural pain reduction and high patient satisfaction, while maintaining a favorable safety profile.

This systematic review and meta-analysis aimed to conduct a systematic review and meta-analysis to evaluate whether opioid-free anesthesia (OFA) is as effective as opioid-based anesthesia (OBA) in managing perioperative pain in spine surgery patients. Given the well-documented adverse effects of opioids, there has been a growing interest in performing surgeries using OFA. However, the effectiveness of OFA in managing postoperative pain remains uncertain. Prior studies have yielded inconclusive results, and to date, no systematic review of randomized controlled trials (RCTs) has evaluated completely opioid-free analgesia in spine surgery. A systematic review was performed using PubMed, Web of Science, and Embase, with results imported into Covidence. Two reviewers independently screened 1,376 titles and abstracts, reviewed 54 full-text articles, and extracted data from eight eligible RCTs. Extracted outcomes included patient- reported postoperative pain, pain-free period, rescue analgesia use, and postoperative nausea/vomiting (PONV). Statistical analysis was conducted using RevMan Web with results reported as mean differences (MDs) and risk ratios (RR). OFA group reported lower postoperative visual analog scale scores than the OBA group (MD, -18.22), though the difference was not statistically significant. OFA showed a significantly lower risk of rescue analgesia use in the post-anesthesia care unit (RR, 0.34) and a significantly longer postoperative pain-free period (MD, 3.36 hours). At 24 hours, numerical rating scale scores were significantly lower in the OFA group (MD, -0.79). OFA also resulted in significantly reduced total rescue analgesia consumption (MD, -4.15 mg oral morphine) and a significantly lower risk of postoperative nausea and vomiting (RR, 0.56). OFA is effective in certain spine surgeries, offering comparable or improved pain control 24 hours postoperatively, reduced rescue analgesia use, and less PONV. Further studies are needed to obtain more robust findings.

Study design: Retrospective observational study.

Purpose: This study aimed to determine the predictive utility of Hounsfield unit (HU) values, derived from single-slice computed tomography (CT) images, for identifying postoperative pedicle screw (PS) loosening in patients undergoing lumbar interbody fusion. The HU values were specifically measured along the planned PS trajectory.

Overview of literature: PS loosening is a frequent complication following spinal fusion surgery, particularly in individuals with compromised bone quality. Although prior research has explored the correlation between screw loosening and general vertebral HU values or bone mineral density, the specific predictive capability of a simple, single-slice measurement along the screw path remains a gap in the literature.

Methods: We retrospectively reviewed data from 47 patients (212 screws) who underwent lumbar interbody fusion between November 2020 and September 2022. Preoperative CT images were used to measure HU values in both the vertebral body and along the PS trajectories. Patients were then stratified into two groups based on the presence (L group, n=9) or absence (no-loosening [NL] group, n=38) of screw loosening identified on 1-year follow-up CT. Comparative analyses were conducted, followed by a receiver operating characteristic curve analysis to establish the optimal predictive HU cutoff.

Results: The incidence of postoperative screw loosening was 11.8% (25/212). While no significant inter-group differences were observed regarding age, bone mineral density, or vertebral body HU values, the PS trajectory HU was significantly lower in the L group (111±40) compared to the NL group (157±74) (p <0.001). Receiver operating characteristic curve analysis identified an optimal HU cutoff of 123. The area under the curve was 0.7106, with an odds ratio of 3.18, sensitivity of 0.31, and specificity of 0.41.

Conclusions: Lower HU values measured along the PS trajectory using single-slice CT images were significantly associated with a higher risk of screw loosening. This straightforward method may serve as a valuable tool for identifying high-risk patients during the preoperative planning phase of spinal fusion surgery.

Lumbar interbody fusion is widely employed to treat degenerative spinal conditions. The procedure frequently involves the use of intervertebral cages to enhance segmental stability and facilitate spinal fusion. While bilateral cage placement has traditionally been the standard approach, recent studies have questioned its routine use. This meta-analysis aimed to determine whether unilateral cage placement offers comparable safety and efficacy to bilateral placement in lumbar interbody fusion. A comprehensive search of PubMed, Scopus, and Cochrane databases identified eight eligible randomized control trials involving 509 patients. The primary outcome was the spinal fusion rate. Secondary outcomes included surgery-related outcomes (operative time, estimated blood loss, length of stay), patientreported outcomes VAS, ODI, patient satisfaction), and complications. The analysis revealed no significant differences in successful spinal fusion rates between the two groups (p =0.41). Unilateral cage placement was significantly associated with shorter operation time (p <0.0001) and reduced estimated blood loss (p <0.0001). However, the length of hospital stay was not significantly affected by the number of cages used (p =0.05). Patient-reported outcomes, including Visual Analog Scale (VAS) for back pain (p =0.61), VAS for leg pain (p =0.64), Oswestry Disability Index score (p =0.18), and patient-reported rate of successful clinical outcomes (p =0.55), exhibited no substantial differences between the two groups. Patients in the unilateral group exhibited a lower overall risk of complications (p =0.03), but no difference in the risk of cage migration was noted between the two groups (p =0.97). Unilateral cage placement for lumbar interbody fusion is as effective as bilateral cage placement in achieving fusion, without compromising patient outcomes. Furthermore, it offers significant advantages, such as decreased operative time, blood loss, and complication risk.

Study design: A retrospective study.

Purpose: To compare the predictive utility between Hounsfield unit (HU) values and vertebral bone quality (VBQ) scores for adjacent vertebral fracture (AVF) risk after balloon kyphoplasty (BKP) and to identify the appropriate measurement site.

Overview of literature: HU and VBQ have emerged as novel bone strength assessment methods. However, no study has compared the efficacy of these methods for evaluating AVF risk.

Methods: This single-center study included 130 patients with osteoporotic vertebral fractures who underwent BKP and preoperative computed tomography and magnetic resonance imaging. After propensity score matching for age; sex; body mass index; fracture level; use of steroids, teriparatide, or osteoporosis medication; and previous AVF, patients were classified into the AVF (-) and AVF (+) groups, each of which included 34 patients. Bone strength was assessed using the L1 HU, L1-4 HU (mean HU of L1-L4), L1 VBQ, and L1-4 VBQ. Group differences were analyzed, and the predictive accuracy for AVF was evaluated using area under the receiver operating characteristic curve (AUC).

Results: L1 HU was significantly lower in the AVF (+) group than in the AVF (-) group (92.1±29.4 vs. 71.6±21.4, p =0.013). No significant differences between the groups were observed for L1-4 HU, L1 VBQ, and L1-4 VBQ. L1 HU had the highest AUC (0.657), compared with those for L1-4 HU (0.625), L1 VBQ (0.524), and L1-4 VBQ (0.523). The predictive accuracy of L1 was superior to that of L1-4 for both HU and VBQ scores.

Conclusions: HU was superior to VBQ in predicting AVF risk after BKP, with L1 HU being the most effective indicator of bone strength and AVF risk.