Gun Woo Lee

A Prospective Randomized Clinical Trial Comparing Bone Union Rate Following Anterior Cervical Discectomy and Fusion Using a Polyetheretherketone Cage: Hydroxyapatite/B-Tricalcium Phosphate Mixture versus Hydroxyapatite/Demineralized Bone Matrix Mixture

Study Design Prospective randomized noninferiority trial. Purpose To evaluate whether the union rate of anterior cervical discectomy and fusion (ACDF) using a polyetheretherketone (PEEK) cage filled with a mixture of hydroxyapatite (HA) and demineralized bone matrix (DBM) is inferior to that of a mixture of β-tricalcium phosphate (β-TCP) and HA. Overview of Literature There have been no clinical trials investigating the outcomes of a mixture of HA and DBM in a PEEK cage in ACDF. Methods Eighty-five eligible patients were randomly assigned to group B (n=43), in which a PEEK cage with a mixture of HA and DBM was used, or group C (n=42), in which a PEEK cage with a mixture of HA and β-TCP was used. The primary study endpoint was the fusion rate, which was assessed with dynamic radiographs and computed tomography (CT) scans. Secondary endpoints included pain intensity using a visual analogue scale, functional outcome using a neck disability index score, laboratory tests of inflammatory profiles, and the infection rate. Results Seventy-seven patients (38 in group B and 39 in group C) were included in the final analysis. One year postoperatively, bone fusion was achieved in 87% of group B patients and 87% of group C patients on dynamic radiographs, and 87% of group B patients and 72% of group C patients on CT scans (p=1.00 and 0.16, respectively). There were also no between-groups differences with respect to the secondary endpoints. Conclusions A HA/DBM mixture inside a PEEK cage can provide noninferior outcomes compared to a HA/TCP mixture in ACDF.

A reconstruction with extracorporeal irradiated autograft in osteosarcoma around the knee

An extracorporeal irradiated (ECI) autograft was first reported in Israel in 1968 for the treatment of primary malignant bone tumor. However, subsequent reports covered mostly short‐term follow up results, and the reported results of reconstruction vary from study to study. We analyze the long‐term follow up results of reconstruction using an extracorporeal irradiated (ECI) autograft in osteosarcoma around the knee.

Feasibility Study of Free-Hand Technique for Pedicle Screw Insertion at C7 without Fluoroscopy-Guidance.

Study Design Retrospective interventional study. Purpose To introduce a free-hand pedicle screw (PS) insertion technique without fluoroscopic guidance in the C7 vertebra and evaluate the procedures feasibility and radiologic outcomes. Overview of Literature Although PS insertion at C7 has been recognized as a critical procedure in posterior cervical fusion surgery, conventional techniques for C7 PS have several limitations. Methods Thirty two patients (64 screws) who underwent PS insertion in C7 with the novel technique were included in this study. Postoperative clinical and radiological outcomes were evaluated. Special attention was paid to the presence of any problems in the screw position including cortical breaches of the PS and encroachment of the PS into the spinal canal or the vertebral foramen. This novel technique for PS insertion in C7 without fluoroscopy guidance had three key elements. First, the ideal PS entry point was chosen near the C6–7 facet joint using preoperative images. Second, the convergent angle distance was measured at axial computed tomography (CT) imaging, which defined the distance between the tip of C7 spinous process and the extended line passing through the pedicle axis from the ideal entry point. Third, the cranial-caudal angle distance was measured in sagittal CT images, which defined the distance between the tip of the C7 spinous process and the extended line passing through the pedicle axis. Results Cortical breach on postoperative CT images was observed in three screws. All violated only the lateral wall of the affected pedicle. The breached screws occurred in the initial five cases. Postoperative neurologic deterioration was not observed in any patient, regardless of cortical breaching. Conclusions The novel technique successfully allows for C7 PS to be placed and is associated with a low rate of cortical breach.

Wedge-shaped Resection of the Posterior Bony Arch During Open Door Laminoplasty to Prevent Postoperative Motion Limitation

Study Design. Prospective randomized double-arm noninferiority study. Objective. To evaluate an additional surgical procedure (wedge-shaped resection of the cranial portion of the posterior bony arch) during open-door laminoplasty (ODLP), and to compare the outcomes with those of conventional ODLP surgery. Summary of Background Data. In clinical practice, spine surgeons sometimes encounter patients who show bony impingement on lateral radiographs after ODLP; bony impingement may lead to reduced motion of the cervical spine and posterior neck pain. However, this problem has not been well studied, and no methods have been developed to prevent it. Methods. Of total 79 patients, 75 were enrolled and randomly assigned to either group A (additional procedure in ODLP, n = 38) or group B (ODLP alone, n = 37). The primary outcome measure was range of motion (ROM) of the cervical spine. Secondary endpoints included clinical outcomes based on pain intensity, 12-item short form health survey (SF-12), and modified Japanese Orthopedic Association scale; presence of bony impingement on dynamic lateral radiographs; surgical outcomes; and surgery-related complications. Results. ROM of the cervical spine was significantly greater at 6 months (P = 0.04) and 1 year (P = 0.02) postoperative in group A than in group B. Pain intensity at the posterior neck was significantly lower 1 year after surgery in group A than in group B (P = 0.03). In lateral radiographs 1 year after surgery, the presence of posterior bony impingement was 0% in group A and 32.4% in group B (P <0.01). Clinical outcomes and surgery-related complications were similar between groups. Conclusion. Performing wedge-shaped resection of the cranial portion of the posterior bony arch in ODLP surgery can lead to better outcomes than ODLP alone in terms of preservation of cervical ROM, prevention of posterior bony impingement, and amelioration of posterior neck pain. Level of Evidence: 2

Which Technique Is Better Option for C3 Segment in Multilevel Open-door Laminoplasty of the Cervical Spine?: Laminectomy versus Laminoplasty

Study Design. A post-hoc comparative study. Objective. To evaluate postoperative clinical, radiological, and surgical outcomes after laminoplasty (LP) involving the C3 segment and to compare outcomes with those of patients who underwent LP with C3 laminectomy (LN). Summary of Background Data. In many of the pathologies that require LP involving C3 segment, most spine surgeons perform LP at C3 and other cervical segments. Considering the peculiarities of the C2-C3 level, spine surgeons should take into account those in LP involving the C3 segment, but the particular aspects of the C2-C3 levels have not been fully evaluated. Methods. Of 93 patients, 66 patients (39 in group A, LP involving C3; 27 in group B, LP with C3 LN) were enrolled in the study. The primary outcome measure was pain intensity of the posterior neck measured with visual analog scale. Secondary endpoints included the following: (1) radiologic outcomes based on the cervical range of motion and rate of bony impingement and spontaneous fusion between C2 and C3, (2) clinical outcomes based on the 12-item short-form health survey and Japanese Orthopedic Association scale, and (3) surgical outcomes. Results. The primary end-point of the present study, posterior neck pain, exhibited a greater improvement in the group with C3 LN than in the group with C3 LP at 6 months and 1 year after surgery (P = 0.03 and 0.01, respectively). The cervical range of motion of C3 LN group was significantly greater than C3 LP group at postoperative 1 year (P = 0.02). Radiologic evidences of bony impingement and spontaneous fusion between C2 and C3 were significantly greater in C3 LP group than in C3 LN group. Clinical outcomes and surgical outcomes did not differ significantly between groups. Conclusion. We recommend performing LN instead of LP for the C3 segment in cases requiring multilevel LP surgery involving C3. Level of Evidence: 3

A preliminary study on surgical navigation for epiduroscopic laser neural decompression.

Epiduroscopic laser neural decompression is an emerging therapeutic modality to treat lumbar spine pathologies including chronic low back pain, spinal stenosis, and disk herniation via catheter insertion followed by laser ablation of the lesion. Despite the efficacy of epiduroscopic laser neural decompression, excessive radiation doses due to fluoroscopy during epiduroscopic laser neural decompression have limited its widespread application. To address the issue, we propose a surgical navigation system to assist in epiduroscopic laser neural decompression procedures using radiation-free image guidance. An electromagnetic tracking system was used as the basic modality to track the internal location of the surgical instrument with respect to the patient body. Patient-to-image registration was carried out using the point-based registration method to determine the transformation between the coordinate system of the patient and that of the medical images. We applied the proposed system in epiduroscopic laser neural decompression procedures to assess its effectiveness, and the outcomes confirmed its clinical feasibility. To the best of our knowledge, this is a report on the first surgical navigation applied for epiduroscopic laser neural decompression procedure.

Distraction Arthrodesis of the Atlantoaxial Facet Joint with Preservation of the C2 Root for the Management of Intractable Occipital Neuralgia Caused by C2 Root Compression

Introduction Vertical collapse of the C1-C2 facet joint may cause narrowing of the C2 root foramen with root compression, resulting in severe occipital neuralgia. The purpose of this study was to evaluate the prospectively collected outcomes data of a distraction arthrodesis surgical group (Study group) in comparison to a Control group in a non-randomized design. Material and Methods The Study group underwent intraoperative skeletal traction, preservation of the C2 nerve roots, facet joint distraction and insertion of a bone block and cancellous bone into the joint along with posterior fusion, and segmental screw fixation using posterior C1 arch screws instead of lateral mass screws. The Control group had C2 root transection with C1-C2 segmental screw fixation and arthrodesis. Inclusion criteria for both groups were (1) occipital neuralgia caused by C2 root compression confirmed by clinical manifestation and imaging studies including radiographs, CT scan, and MRI, (2) intractable pain (VAS≥7) unresponsive to nonoperative treatment, and (3) follow-up period ≥12 months. We compared the preoperative and postoperative 10-point VAS scores for occipital neuralgia and neck pain; NDI; and JOA scores and recovery rates. Results There were 15 patients in the Study group and 8 in the Control group. All had facet joint destruction and/or collapse caused by underlying disorders including rheumatoid arthritis (Study group: 5 ; Control group: 3), rheumatoid arthritis with odontoid nonunion (2, 0), odontoid nonunion (3, 1), unifacet spondylosis (3, 2), os odontoideum (2, 1), and cerebral palsy (0, 1). There was no significant difference in age (61 ± 6, 62 ± 9), gender (4 and 3 men, respectively), and the number of cases with accompanying myelopathy (5, 2) between the 2 groups. The follow-up period averaged 21 ± 12 versus 33 ± 25 months, respectively. There was no significant difference in the VAS score for the preoperative occipital neuralgia (8.2 ± 0.9, 7.9 ± 0.6, p = 0.39). However, it was significantly lower in the Study group at 1, 3, 6, and 12 months postoperatively (p = <0.01, respectively). At 12 months, the VAS was 0.4 ± 0.6 versus 2.5 ± 2.6 (p = 0.01). In the Study group, all patients had little or no pain (VAS ≤2) while 2 patients (25%) in the Control group were still on medication (Gabapentin) with moderate to severe pain (VAS 4 and 8 respectively). There was no significant difference in preoperative and postoperative VAS scores for neck pain, NDI, and JOA scores and recovery rate, since these values are minimally influenced by occipital neuralgia. Conclusion Our results suggest that our novel technique of distraction arthrodesis can be an effective option for the management of intractable occipital neuralgia caused by C2 root compression. Prospective randomized studies are required for better evaluation.

Comparison of lumbar discectomy alone and lumbar discectomy with direct repair of pars defect for patients with disc herniation and spondylolysis at the nearby lumbar segment

BACKGROUND CONTEXT It is unknown whether direct repair (DR) of pars defect after lumbar discectomy (LD) for patients with lumbar disc herniation (LDH) and spondylolysis leads to better outcomes than LD alone. PURPOSE The aim was to compare two surgical methods, LD alone and LD with DR, for LDH patients with spondylolysis at a nearby lumbar segment. STUDY DESIGN This was a retrospective comparative study. PATIENT SAMPLE This study enrolled 89 patients who were diagnosed with LDH and spondylolysis at the same or adjacent lumbar segment and were followed up for at least 1 year. OUTCOME MEASURE The primary outcome was pain intensity of the lower back and lower extremities as measured with visual analog scale. Secondary outcomes included clinical outcomes as assessed with the Oswestry Disability Index and the 12-item short form health survey, radiologic outcomes as assessed with the gap distance and the union rate at the pars defect, surgical outcomes, and complications. METHODS Enrolled patients were classified into two groups: LD alone (Group A, 48 patients) and LD with DR (Group B, 41 patients). RESULTS Pain intensity of the lower back and lower extremities and clinical outcomes were significantly improved 1 year after surgery compared with preoperative scores. However, the scores in the group receiving LD alone steadily worsened during follow-up, whereas the scores in the group receiving LD with DR did not deteriorate over time. The difference in the gap distance of the pars defect between baseline and 1 year after surgery was significantly different between the groups. The fusion rate of the pars defect was 59% (24/41). With the exception of surgical time, which was longer in Group B, surgical outcomes and complications did not differ significantly between the groups. CONCLUSIONS At the 1-year follow-up, DR after LD was associated with better outcomes for LDH with spondylolysis than LD alone.