Hyun-Joon Jang
Yonsei University · Medicine
About the Lab
Professor Hyun-Joon Jang's research lab specializes in spinal surgery and deformity, with a strong focus on improving surgical outcomes through advanced imaging, biomechanical analysis, and personalized risk prediction. The lab investigates critical complications such as implant subsidence, proximal junctional kyphosis (PJK), and mechanical failures after spinal fusion, particularly in adult spinal deformity and degenerative conditions. A key direction involves developing patient-specific predictive models—such as risk calculators for PJK and evaluation of anatomical parameters like the K-line and T1 slope—to guide precision spinal surgery. The lab also explores the impact of frailty and short-term prognosis in elderly patients, emphasizing individualized decision-making in high-risk populations.
Research Overview
Research Output Trend
Figures are computed from collected data and may differ slightly.
Selected Papers
15STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Implant subsidence is an important prognostic factor after anterior cervical discectomy and fusion (ACDF). Our purpose in this study was to investigate whether graft position affects subsidence after ACDF and to determine if there is a difference in clinical results based on allograft subsidence and position. METHODS: We reviewed 92 patients who underwent single-level ACDF with allograft and plate between January 2012 and October 2018. Treatme
OBJECTIVE: Although adult spinal deformity (ASD) surgery aims to restore and maintain alignment, proximal junctional kyphosis (PJK) may occur. While existing scoring systems predict PJK, they predominantly offer a generalized 3-tier risk classification, limiting their utility for nuanced treatment decisions. This study seeks to establish a personalized risk calculator for PJK, aiming to enhance treatment planning precision. METHODS: Patient data for ASD were sourced from the Korean spinal deform
There was no relationship in long-term survival according to frailty in patients 80 years of age or older, but a difference was identified in short-term mortality. When making a surgical decision for lumbar spine surgery in frail patients over 80 years of age, surgeons should pay attention to the short-term prognosis.
OBJECTIVE: In this study, we investigate about relationship between postoperative global sagittal imbalance and occurrence of mechanical complications after adult spinal deformity (ASD) surgery. In global sagittal balance parameters, odontoid-hip axis (OD-HA) angle and T1 pelvic angle (TPA) were analyzed. METHODS: Between January 2009 and December 2016, 199 consecutive patients (26 males and 173 females) with ASD underwent corrective fusion of more than 4 levels and were followed up for more tha
OBJECTIVE: To evaluate the impact of the K-line and canal-occupying ratio (COR) on surgical outcomes in patients with multilevel cervical ossification of the posterior longitudinal ligament (OPLL). METHODS: Patients with cervical myelopathy due to multilevel OPLL who underwent decompression surgery (anterior or posterior) from 2013 to 2022, with 2-year minimum follow-up, were enrolled. Radiological evaluations included K-line, COR, OPLL type/level, and cervical parameters (C2 slope [C2S], T1 slo
High-flow vertebral arteriovenous fistulas (VAVF) are rare complications of cervical spine surgery and characterized by iatrogenic direct-communication of the extracranial vertebral artery (VA) to the surrounding venous plexuses. The authors describe two patients with VAVF presenting with ischemic presentation after C1 pedicle screw insertion for a treatment of C2 fracture and nontraumatic atlatoaxial subluxation. The first patient presented with drowsy consciousness with blurred vision. The dif
Adjacent segment disease (ASD) is a prevalent complication following lumbar fusion surgery, representing a significant challenge in spinal surgery. This study aimed to assess the long-term outcomes of Nitinol spring rod semi-rigid fixation, a potential alternative to traditional rigid fixation, in reducing the incidence of ASD. This retrospective case study evaluated 89 patients who underwent lumbar or lumbosacral surgeries using a combination of Bioflex® (a Nitinol spring rod dynamic stabilizat
OBJECTIVE: Spinal stenosis is a prevalent condition; however, the optimal surgical treatment for central lumbar stenosis remains controversial. This study compared the clinical outcomes and radiological parameters of 3 surgical. METHODS: unilateral laminectomy bilateral decompression with unilateral biportal endoscopy (ULBD-UBE), conventional subtotal laminectomy (STL), and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). METHODS: This retrospective study included 86 patient
Proximal junctional vertebral compression fractures with greater early-stage decrement of adjacent disc height were associated with increased risk of future neurological deterioration and necessity of revision. The condition of adjacent disc degeneration should be considered regarding severity and revision rate of proximal junctional kyphosis/proximal junction failures.
OBJECTIVE: This study aimed to investigate the efficacy of transverse process (TP) hook system at the upper instrumented vertebra (UIV) for preventing screw pullout in adult spinal deformity surgery using the pedicle Hounsfield unit (HU) stratification based on K-means clustering. METHODS: We retrospectively reviewed 74 patients who underwent deformity correction surgery between 2011 and 2020 and were followed up for >12 months. Pre- and post-operative data were used to determine the incidence o
EOS showed a negative SVA shift and lesser PT compared to WSX, especially in patients with sagittal imbalance. When preparing a surgical plan, surgeons should consider these differences between EOS and WSX.
OBJECTIVE: Spinal intramedullary hemangioblastoma is a rare and highly vascularized benign tumor. The characteristics of the tumor, its corresponding location, and surgical outcomes remain unknown. The purpose of this study was to identify risk factors and strategies for neurologic deterioration following hemangioblastoma surgery. METHODS: A comprehensive retrospective analysis was undertaken to evaluate patients who underwent surgical intervention for intramedullary hemangioblastoma at our inst
Pain is subjective and varies among individuals. Doctors determine pain severity based on a patient’s self-reported symptoms. In such situations, a language barrier may prevent patients from expressing their pain accurately, which may cause doctors to underestimate their pain degree. Moreover, patients’ subjective descriptions of pain can determine their eligibility for secondary benefits, as in the case of compensation for traffic or industrial accidents. Therefore, to perform a multiclass pred
Research Areas
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