Sung-Min Kim

Background and Objectives: Long spinal fusion terminating at L5 remains controversial because of the risk of postoperative junctional failure. Although degeneration of the residual L5–S1 disc has been suggested as a contributing factor, the relative impact of disc degeneration versus sagittal spinopelvic alignment on different junctional failure patterns has not been fully clarified. Materials and Methods: This retrospective cohort study included 47 patients aged ≥60 years who underwent ≥5-level thoracolumbar fusion ending at L5 with a minimum follow-up of 2 years. Junctional failures were classified as proximal junctional failure (PJF) or distal junctional failure (DJF). Preoperative L5–S1 disc degeneration was assessed using modified Weiner and Pfirrmann classifications. Spinopelvic parameters were measured preoperatively, postoperatively, and at final follow-up. Junctional failure–free survival was analyzed using the Kaplan–Meier method, and risk factors were explored using Cox proportional hazards models. Results: Junctional failures occurred in 28 patients (59.6%), including 16 PJFs (34.0%) and 10 DJFs (21.3%). Lower grades of L5–S1 disc degeneration (Weiner grades 0–1) were more frequently associated with PJFs, whereas higher grades (≥2) were predominantly associated with DJFs (p = 0.024). Multivariate analysis showed that preoperative thoracolumbar kyphosis (hazard ratio [HR] = 1.164), preoperative T1 pelvic angle (HR = 1.269), and postoperative pelvic incidence–lumbar lordosis mismatch (HR = 0.877) as significant risk factors for PJF. Postoperative proximal junctional angle (HR = 0.899) and lumbar lordosis (HR = 0.920) were independently associated with DJF. Conclusions: Sagittal spinopelvic alignment parameters appear to have a greater influence on junctional failure patterns than residual L5–S1 disc degeneration in long fusions terminating at L5. Adequate sagittal correction should be prioritized to reduce the risk of both proximal and distal junctional failures.

Enhanced recovery after surgery (ERAS) protocols have been widely adopted in various surgical disciplines to accelerate recovery and improve patient outcomes. However, the application of these programs in spinal surgery, particularly with an integrative medicine approach, remains limited. This study aimed to evaluate the effects of a customized integrative medicine-based program on postoperative recovery and to analyze patient-reported preferences for future protocol refinement. This study evaluated the enhanced recovery after spinal surgery (ERAS-K) program in single- and multi-segment spinal fusion surgeries, targeting improved activity as the primary endpoint. Secondary endpoints included pain, digestive dysfunction, and muscle weakness. Patients aged >40 years were divided into ERAS-K and non-ERAS-K groups. Statistical analyses, including ANCOVA and chi-square tests, adjusted for covariates, revealing significant outcomes ( P -values adjusted via Benjamini–Hochberg). This study evaluated the ERAS-K program in single- and multi-segment spinal fusion surgeries, with improved activity as the primary endpoint. Secondary endpoints included pain, digestive dysfunction, and muscle weakness. Patients aged >40 years were divided into ERAS-K (N) and non-ERAS-K (M) groups. Postoperative recovery metrics showed no significant differences in numeric rating scale-axial ( P = .5588) or numeric rating scale-leg ( P = .8576) pain scores at baseline. Postoperatively, axial pain reduction showed a near-significant trend ( P = .0525, ANCOVA; ERAS-K: 4.2 ± 1.1, non-ERAS-K: 4.8 ± 1.3). Short form-36 physical ( P = .1989; ERAS-K: 42.5 ± 8.2, non-ERAS-K: 41.3 ± 7.9) and mental component scores ( P = .9572) were similar. Mean days to improved activity were 4.81 ± 0.9 (ERAS-K) versus 4.96 ± 1.0 (non-ERAS-K; P = .63551). Non-ERAS-K patients preferred physical therapy ( P = .053). Outcomes suggest ERAS-K’s integrated rehabilitation may reduce the need for standalone physical therapy, though statistical significance was not achieved. Although the ERAS-K program did not demonstrate a statistically significant impact on conventional pain and quality-of-life metrics, this study highlights the critical importance of program standardization in future research. The findings also underscore strong patient-driven demand for the integration of traditional Korean medicine into conventional postoperative care pathways, suggesting that a holistic, patient-centered approach may improve satisfaction and outcomes beyond traditional metrics.

Yoon JY, et al. Yonsei Med J. 2026 Jun;67(6):492-501. https://doi.org/10.3349/ymj.2025.0325

Background and Objectives: The selection of the optimal distal level of fusion in long-level fusion surgery remains controversial. Fusion ending at L5 preserves motion but increases the risk of L5–S1 disc degeneration. The L5 laminar hook has been introduced to enhance distal fixation, but its indications and clinical effects remain unclear. This study aimed to investigate the indication of the L5 laminar hook and its effect on adjacent segment degeneration when performing long-level fusion terminating at L5 in patients with degenerative sagittal imbalance (DSI). Materials and Methods: 112 patients with DSI who had undergone corrective surgery and ended at L5 were analyzed retrospectively. Finally, 64 were treated with an L5 laminar hook (Group I), while 48 were not (Group II). We compared radiographic spinopelvic parameters between the two groups and followed up disc degeneration at the L5–S1 level. Additional analysis was conducted within Group I to determine the indications for L5 laminar hook. Results: Preoperative C7 sagittal vertical axis (C7SVA), lumbar lordosis (LL), and pelvic incidence (PI)-LL mismatch were significantly greater in Group I than in Group II (p < 0.05). At 2 years of follow-up, advanced L5–S1 disc degeneration had developed in 14 patients (21.9%) in Group I and 36 patients (75%) in Group II. Patients in Group B (exacerbated L5–S1) had a significantly higher body mass index (BMI), larger preoperative C7SVA, and PI-LL mismatch than patients in Group A (preserved L5–S1). The C7SVA and PI-LL mismatch cut-off values for Group A were 15.8 cm and 40.8°, respectively. Conclusions: L5 laminar hook helps to reduce disc degeneration at the L5–S1 level and can be used to maintain the deformity correction ending at L5 in patients with DSI. We propose a series of indicators for the use of L5 laminar hooks in patients with DSI: a low BMI, a PI-LL mismatch < 40.8°, and a C7SVA < 15.8 cm.

Background and Objectives: This study aimed to identify radiographic predictors and optimal cut-off values for determining the need for additional pedicle subtraction osteotomy (PSO) in patients with iatrogenic flatback syndrome following short-segment (≤3 levels) fusion surgery. Materials and Methods: From 2011 to 2022, a total of 49 patients who underwent deformity correction for iatrogenic flatback following short-segment fusion at a single institution were included. We divided all patients into group A (n = 33, only anterior column realignment, ACR) and group B (n = 16, ACR combined with PSO). Among group A patients, we further divided them into two subgroups: The Excessive group, who developed excessive anterior disc height distraction (EADH) during surgery, and the Non-excessive group, who did not. The Receiver Operating Characteristic (ROC) curve was used to determine the cut-off values for spinopelvic parameters associated with the decision to perform additional PSO. Results: Group A had a significantly lower number of previously fused segments compared to Group B (p < 0.001). Preoperative C7 sagittal vertical axis (C7SVA, p = 0.026) and its correction (p = 0.003) in group B were greater than those in group A. Group B showed a significantly more kyphotic preoperative fused segment angle (FSA) compared to Group A (p = 0.001). Postoperatively, EADH occurred in 7 patients (21.2%) in Group A, while no cases were observed in Group B. Subgroup analysis revealed that the dynamic segment angle (DA) was significantly lower in the Excessive group compared to the Non-excessive group (p < 0.001). The optimal cut-off values of preoperative radiographic parameters for selecting PSO were: C7-SVA > 242.8 mm, FSA > −3.2°, and DA < 4.3°. Conclusions: ACR alone and ACR combined with PSO showed satisfactory outcomes in patients with iatrogenic flat back. For selected patients with preoperative C7SVA > 242.8 mm, FSA > −3.2°, or DA < 4.3°, additional PSO may be reasonable to help optimize sagittal alignment.

Background and Objectives: To investigate the indication of the L5 laminar hook and its effect on adjacent segment degeneration when performing long-segment fusion terminating at L5 in patients with degenerative sagittal imbalance (DSI). Materials and Methods: 112 patients with DSI who had undergone corrective surgery and ended at L5 were analyzed retrospectively. Finally, 64 were treated with an L5 laminar hook (Group I), while 48 were not (Group II). We compared radiographic spinopelvic parameters between the two groups and followed up disc degeneration at the L5-S1 level. Additional analysis was conducted within Group I to determine the indications for L5 laminar hook. Results: Preoperative C7 sagittal vertical axis (C7SVA), lumbar lordosis (LL), and pelvic incidence (PI)-LL mismatch were significantly greater in Group I than in Group II (p<0.05). On 2 years follow-up, advanced L5-S1 disc degeneration had developed in 14 patients (21.9%) in Group I and 36 patients (75%) in Group II. Patients in Group B (exacerbated L5-S1) had a significantly higher body mass index (BMI), larger preoperative C7SVA, and PI-LL mismatch than patients in Group A (preserved L5-S1). The C7SVA and PI-LL mismatch cut-off values for Group A were 15.8 cm and 40.8°, respectively. Conclusions: L5 laminar hook helps the effective correction of sagittal balance by preventing the progression of disc degeneration at the L5-S1 level. We propose a series of indicators for the use of L5 laminar hooks in patients with DSI: a low BMI, a PI-LL mismatch < 40.8°, and a C7SVA < 15.8 cm.

Background and Objectives: This study aimed to identify radiographic predictors and opti-mal cut-off values for determining the need for additional pedicle subtraction osteotomy (PSO) in patients with iatrogenic flatback syndrome following short-segment (≤3 levels) fusion surgery. Materials and Methods: From 2011 to 2022, a total of 49 patients who un-derwent deformity correction for iatrogenic flatback following short-segment fusion at a single institution were included. We divided all patients into group A (n= 33, only ACR) and group B (n= 16, ACR combined with PSO). Among group A patients, we further di-vided them into two subgroups: The Excessive group, who developed excessive anterior disc height distraction (EADH) during surgery, and the Non-excessive group, who did not. The Receiver Operating Characteristic (ROC) curve was used to determine the cut-off val-ues for spinopelvic parameters associated with the decision to perform additional PSO. Results: Group A had a significantly lower number of previously fused segments com-pared to Group B (p < 0.001). Preoperative C7 sagittal vertical axis (C7SVA, p=0.026) and its correction (p=0.003) in group B were greater than those in group A. Group B showed a significantly more kyphotic preoperative fused segment angle (FSA) compared to Group A (p = 0.001). Postoperatively, EADH occurred in 7 patients (21.2%) in Group A, while no cases were observed in Group B. Subgroup analysis revealed that the dynamic segment angle (DA) was significantly lower in the Excessive group compared to the Non-excessive group (p 242.8mm, FSA > -3.2°, and DA < 4.3°. Conclusions: ACR alone and ACR combined with PSO showed satisfactory outcomes in patients with iatro-genic flat back. In particular, we highly recommend ACR combined with the PSO in pa-tients with preoperative C7SVA > 242.8 mm, FSA > -3.2°, or DA < 4.3°.

Background and Objectives: This study is a retrospective analysis aimed at understanding the incidence and risk factors of proximal junctional kyphosis (PJK) following long-instrumented spinal fusion from L1 to the sacrum in patients with mild to moderate sagittal imbalance. Materials and Methods: It recruited consecutive patients undergoing instrumented fusion from L1 to the sacrum for degenerative lumbar disease between June 2006 and November 2019 in a single institution. The patients’ preoperative clinical data, muscle status at T12-L1 on magnetic resonance images, and sagittal spinopelvic parameters were analyzed. Univariate analysis was used to compare clinical and radiographic data between PJK and non-PJK patients. Logistic regression analysis was used to investigate the independent risk factors for PJK. Results: A total of 56 patients were included in this study. The mean age at surgery was 67.3 years and mean follow-up period was 37.3 months. In total, 10 were male and 46 were female. PJK developed in 23 (41.1%) out of 56; of these patients, 20 (87.0%) developed PJK within 1 year postoperatively. In the univariate analysis between PJK and non-PJK patients, the PJK group showed more frequent osteoporosis, lower body mass index, smaller cross-sectional area (CSA) and more fat infiltration (FI) in erector spinae muscle at T12-L1 and larger preoperative TLK and PT with statistical significance (p < 0.05). In the logistic regression analysis, severe (>50%) FI in erector spinae muscle (OR = 43.60, CI 4.10–463.06, R₂N = 0.730, p = 0.002) and osteoporosis (OR = 20.49, CI 1.58–264.99, R₂N = 0.730, p = 0.021) were statistically significant. Conclusions: Preexisting severe (>50%) fat infiltration in the erector spinae muscle and osteoporosis were independent risk factors associated with PJK following instrumented fusion from L1 to the sacrum, but age was not a risk factor.

Background and Objectives: Many risk factors for postoperative C5 palsy (PC5P) have been reported regarding a “cord shift” after a posterior approach. However, there are few reports about shoulder traction as a possible risk factor of anterior cervical surgery. Therefore, we assessed the stretched nerve roots when shoulder traction was applied on cadavers. Materials and Methods: Eight cadavers were employed in this study, available based on age and the presence of foramen stenosis. After dissecting the sternocleidomastoid muscle of the cadaver, the shoulder joint was pulled with a force of 2, 5, 8, 10, 15, and 20 kg. Then, the stretched length of the fifth nerve root was measured in the extra-foraminal zone. In addition, the same measurement was performed after cutting the carotid artery to accurately identify the nerve root’s origin. After an additional dissection was performed so that the superior trunk of the brachial plexus could be seen, the stretched length of the fifth and sixth nerve roots was measured again. Results: Throughout the entire experiment, the fifth nerve root stretched out for an average of 1.94 mm at 8 kg and an average of 5.03 mm at a maximum force of 20 kg. In three experiments, the elongated lengths of the C5 nerve root at 8 kg and 20 kg were 1.69/4.38 mm, 2.13/5.00 mm, and 0.75/5.31 mm, respectively, and in the third experiment, the elongated length of the C6 nerve root was 1.88/5.44 mm. Conclusions: Although this was a cadaveric experiment, it suggests that shoulder traction could be the risk factors for PC5P after anterior cervical surgery. In addition, for patients with foraminal stenosis and central stenosis, the risk would be higher. Therefore, the surgeon should be aware of this, and the patient would need sufficient explanation.