Kyeong-Sik Ryu

Accuracy and Safety in Pedicle Screw Placement in the Thoracic and Lumbar Spines : Comparison Study between Conventional C-Arm Fluoroscopy and Navigation Coupled with O-Arm® Guided Methods.

Objective The authors performed a retrospective study to assess the accuracy and clinical benefits of a navigation coupled with O-arm® system guided method in the thoracic and lumbar spines by comparing with a C-arm fluoroscopy-guided method. Methods Under the navigation guidance, 106 pedicle screws inserted from T7 to S1 in 24 patients, and using the fluoroscopy guidance, 204 pedicle screws from T5 to S1 in 45 patients. The position of screws within the pedicle was classified into four groups, from grade 0 (no violation cortex) to 3 (more than 4 mm violation). The location of violated pedicle cortex was also assessed. Intra-operative parameters including time required for preparation of screwing procedure, times for screwing and the number of X-ray shot were assessed in each group. Results Grade 0 was observed in 186 (91.2%) screws of the fluoroscopy-guided group, and 99 (93.4%) of the navigation-guided group. Mean time required for inserting a screw was 3.8 minutes in the fluoroscopy-guided group, and 4.5 minutes in the navigation-guided group. Mean time required for preparation of screw placement was 4 minutes in the fluoroscopy-guided group, and 19 minutes in the navigation-guided group. The fluoroscopy-guided group required mean 8.9 times of X-ray shot for each screw placement. Conclusion The screw placement under the navigation-guidance coupled with O-arm® system appears to be more accurate and safer than that under the fluoroscopy guidance, although the preparation and screwing time for the navigation-guided surgery is longer than that for the fluoroscopy-guided surgery.

Radiological changes of the operated and adjacent segments following cervical arthroplasty after a minimum 24-month follow-up: comparison between the Bryan and Prodisc-C devices

OBJECT The purposes of this retrospective study were to determine the radiological changes at the index and adjacent levels after cervical arthroplasty using the Bryan disc and Prodisc-C disc after a minimum 24 months follow-up, and to demonstrate the possible clinical factors related to these changes. METHODS Following single-level cervical arthroplasty using either the Bryan disc or Prodisc-C, the degree of facet degeneration and other radiological changes at the index and adjacent levels were assessed by observing radiographs and CT scans at a minimum 24 months after the operations. These findings were determined in relation to the clinical outcome, various perioperative factors, and prosthesis factors. Thirty-six patients were included in this investigation (19 in the Bryan disc group and 17 in the Prodisc-C group). RESULTS At the index level, progression of facet arthrosis (PFA) was observed in 7 of 36 levels (1 level with the Bryan disc, 6 with the Prodisc-C). At adjacent levels, PFA was minimally observed. Heterotopic ossification (HO) was observed at 19 levels (11 with the Bryan disc, 8 with Prodisc-C). Progression of facet arthrosis at the index segments was positively related to malposition of the prosthesis on the frontal plane, and decreased postoperative functional spinal unit range of motion at the index level. Occurrence of HO was correlated with the preoperative calcification of the posterior longitudinal ligament at the operated level, regardless of prosthesis type. Clinical outcome and the occurrence of PFA or HO did not show any significant relationship. CONCLUSIONS This study demonstrates that the incidence of PFA at the index level is 19.4% after a minimum 24-month follow-up, and occurs more frequently in the Prodisc-C group. Progression of facet arthrosis is related to less functional spinal unit range of motion and anterior placement of the prosthesis. The occurrence rate of HO is high, regardless of the type of prosthesis, and it is significantly correlated with preoperative calcification of the posterior longitudinal ligament at the operated level.

Therapeutic Efficacy of Injectable Calcium Phosphate Cement in Osteoporotic Vertebral Compression Fractures: Prospective Nonrandomized Controlled Study at 6-Month Follow-up

BACKGROUND Alternative biocompatible filler materials replacing polymethylmethacrylate (PMMA) cement have been introduced and clinically tested. Callos calcium phosphate cement (CPC) is one of them. A prospective nonrandomized controlled study was performed to assess the clinical and radiologic results after balloon kyphoplasty with Callos CPC in osteoporotic vertebral compression fractures. METHODS Twenty-six patients were enrolled in this study. Clinical outcome was assessed using the Visual Analogue Scale (VAS) and the Oswestry Disability Index (ODI). The degree of vertebral height loss and changes in the kyphotic angle were measured using plain-film x-rays. Blood tests were carried in all cases out to observe the variation in postoperative serum calcium levels. RESULTS The VAS and ODI scores decreased from 7.5 ± 1.1 to 2.2 ± 1.4 (P = .000) and from 31.7 ± 1.6 to 16.9 ± 1.7 (P = .000), respectively. Although vertebral height loss (M = 25.4% ± 17.4%) was reduced after the operation (M=22.1% ± 15.3%, P = .002), recurrent progression of height loss was observed during the follow-up (M = 32.7% ± 19.6%, P = .001). The kyphotic angle (M = 8.1° ± 4.8°) did not significantly change postoperatively (M = 8.7° ± 5.5°, P = .350), and the serum calcium level was within normal ranges. CPC leakage to the spinal canal was observed in 15 cases (48.4%), and none of them presented any related clinical symptoms except one patient, who had transient intercostal neuralgia. CONCLUSIONS Subsequent loss of augmentation properties during follow-up is a serious problem of kyphoplasty using injectable CPC in osteoporotic vertebral compression fractures. The clinical use of injectable CPC in kyphoplasty should be reconsidered.

The prognostic factors influencing on the therapeutic effect of percutaneous vertebroplasty in treating osteoporotic vertebral compression fractures.

OBJECTIVE This retrospective study of 215 patients with 383 symptomatic osteoporotic vertebral compression fractures (VCFs) treated by percutaneous vertebroplasty (PVP), was performed to evaluate the clinical outcomes, and to analyze the various clinical factors affecting these results. METHODS The authors assessed the clinical outcome under the criteria such as the pain improvement, activity, requirement of analgesics, and the patients satisfaction, and determined the relation to various peri- and intra-operative factors, and postoperative imaging findings. RESULTS The outcome was determined as 84.2% in relief of pain, 72.0% in change in activity, 65.7% in analgesics use, and 84.7% of satisfaction rate. More severe focal back pain, high uptake bone scan, and the lower mean T-score were related to the better pain relief following PVP. The longer the duration between fracture and PVP, the less severe focal back pain, low uptake bone scan, and leakage of PMMA into the paravertebral space were related to the less improvement in activity. Female and low uptake bone scan showed a correlation with more analgesic use. The longer the duration between fracture and PVP, low uptake bone scan, and the higher the mean T-score were correlated with the less the patients satisfaction. CONCLUSION Our study suggests that PVP may be more effective in the acute phase of VCFs, more severe focal pain, and far advanced osteoporosis on BMD. Leakage of PMMA into the paravertebral spcae also could be affecting the surgical results.

Direct pars repair surgery using two different surgical methods : pedicle screw with universal hook system and direct pars screw fixation in symptomatic lumbar spondylosis patients.

Objective The authors performed a retrospective study to assess the clinical and radiological outcome in symptomatic lumbar spondylolysis patients who underwent a direct pars repair surgery using two different surgical methods; pedicle screw with universal hook system (PSUH) and direct pars screw fixation (DPSF), and compared the results between two different treated groups. Methods Forty-seven consecutive patients (PSUH; 23, DPSF; 15) with symptomatic lumbar spondylolysis who underwent a direct pars repair surgery were included. The average follow-up period was 37 months in the PSUH group, and 28 months in the DPSF group. The clinical outcome was measured using visual analogue pain scale (VAS) and Oswestry disability index (ODI). The length of operation time, the amount of blood loss, the duration of hospital stay, surgical complications, and fusion status were also assessed. Results When compared to the DPSF group, the average preoperative VAS and ODI score of the PSUH group were less decreased at the last follow-up; (the PSUH group; back VAS : 4.9 vs. 3.0, leg VAS : 6.8 vs. 2.2, ODI : 50.6% vs. 24.6%, the DPSF group; back VAS : 5.7 vs. 1.1, leg VAS : 6.1 vs. 1.2, ODI : 57.4% vs. 18.2%). The average operation time was 174.9 minutes in the PSUH group, and 141.7 minutes in the DPSF group. The average blood loss during operation was 468.8 cc in the PSUH group, and 298.8 cc in the DPSF group. The average hospital stay after operation was 8.9 days in the PSUH group, and 7 days in the DPSF group. In the PSUH group, there was one case of a screw misplacement requiring revision surgery. In the DPSF group, one patient suffered from transient leg pain. The successful bone fusion rate was 78.3% in the PSUH group, and 93.3% in the DPSF group. Conclusion The present study suggests that the technique using direct pars screw would be more effective than the method using pedicle screw with lamina hook system, in terms of decreased operation time, amount of blood loss, hospital stay, and increased fusion success rate, as well as better clinical outcome.

Sagittal Sacropelvic Morphology and Balance in Patients with Sacroiliac Joint Pain Following Lumbar Fusion Surgery

Objective To investigate the sagittal sacropelvic morphology and balance of the patients with SIJ pain following lumbar fusion. Methods Among 452 patients who underwent posterior lumbar interbody fusion between June 2009 and January 2013, patients with postoperative SIJ pain, being responded to SIJ block were enrolled. For a control group, patients matched for sex, age group, the number of fused level and fusion to sacrum were randomly selected. Patients were assessed radiologic parameters including lumbar lordosis, pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS). To evaluate the sagittal sacropelvic morphology and balance, the ratio of PT/PI, SS/PI and PT/SS were analyzed. Results A total of 28 patients with SIJ pain and 56 patients without SIJ pain were assessed. Postoperatively, SIJ pain group showed significantly greater PT (p=0.02) than non-SIJ pain group. Postoperatively, PT/PI and SS/PI in SIJ pain group was significantly greater and smaller than those in non-SIJ pain group respectively (p=0.03, 0.02, respectively) except for PT/SS (p=0.05). SIJ pain group did not show significant postoperative changes of PT/PI and SS/PI (p=0.09 and 0.08, respectively) while non-SIJ pain group showed significantly decrease of PT/PI (p=0.00) and increase of SS/PI (p=0.00). Conclusion This study presents different sagittal sacropelvic morphology and balance between the patients with/without SIJ pain following lumbar fusion surgery. The patients with SIJ pain showed retroversed pelvis and vertical sacrum while the patients without SIJ pain have similar morphologic features with asymptomatic populations in the literature.

Thoracic Intramedullary Schwannoma Accompanying by Extramedullary Beads-Like Daughter Schwanommas

Thoracic intramedullary schwannomas are rare spinal cord tumors. Most of these tumors have been reported as a single lesion in the spinal cord. The authors report the first case of intramedullary schwannoma accompanying by extramedullary beads-like daughter masses of the thoracic spine. A 68-year-old male presented with walking disturbance and decreased sensation below T10 dermatome. Imaging workup revealed an intramedullary mass at T6 and T7. T6 and T7 laminectomy and mass removal were performed. Intraoperatively, extramedullary beads-like daughter masses along the nerve roots adjacent to intramedullary mass were identified. Total removal of intramedullary lesion and partial resection of extramedullary masses were done. Histological analysis confirmed the diagnosis of schwannoma. The patient could ambulate independently at postoperative 1 month without any neurological sequelae. The authors experienced a surgical case of intramedullary schwannoma accompanying by extramedullary beads-like same pathologies in the thoracic spine.

Comparison of SpineJet XL and Conventional Instrumentation for Disk Space Preparation in Unilateral Transforaminal Lumbar Interbody Fusion.

OBJECTIVE Although unilateral transforaminal lumbar interbody fusion (TLIF) is widely used because of its benefits, it does have some technical limitations. Removal of disk material and endplate cartilage is difficult, but essential, for proper fusion in unilateral surgery, leading to debate regarding the surgerys limitations in removing the disk material on the contralateral side. Therefore, authors have conducted a randomized, comparative cadaver study in order to evaluate the efficiency of the surgery when using conventional instruments in the preparation of the disk space and when using the recently developed high-pressure water jet system, SpineJet XL. METHODS Two spine surgeons performed diskectomies and disk preparations for TLIF in 20 lumbar disks. All cadaver/surgeon/level allocations for preparation using the SpineJet XL (HydroCision Inc., Boston, MA, USA) or conventional tools were randomized. All assessments were performed by an independent spine surgeon who was unaware of the randomizations. The authors measured the areas (cm(2)) and calculated the proportion (%) of the disk surfaces. The duration of the disk preparation and number of instrument insertions and withdrawals required to complete the disk preparation were recorded for all procedures. RESULTS The proportion of the area of removed disk tissue versus that of potentially removable disk tissue, the proportion of the area of removed endplate cartilage, and the area of removed disk tissue in the contralateral posterior portion showed 74.5 +/- 17.2%, 18.5 +/- 12.03%, and 67.55 +/- 16.10%, respectively, when the SpineJet XL was used, and 52.6 +/- 16.9%, 22.8 +/- 17.84%, and 51.64 +/- 19.63%, respectively, when conventional instrumentations were used. The results also showed that when the SpineJet XL was used, the proportion of the area of removed disk tissue versus that of potentially removable disk tissue and the area of removed disk tissue in the contralateral posterior portion were statistically significantly high (p < 0.001, p < 0.05, respectively). Also, compared to conventional instrumentations, the duration required to complete disk space preparation was shorter, and the frequency of instrument use and the numbers of insertions/withdrawals were lower when the SpineJet XL was used. CONCLUSION The present study demonstrates that hydrosurgery using the SpineJet XL unit allows for the preparation of a greater portion of disk space and that it is less traumatic and allows for more precise endplate preparation without damage to the bony endplate. Furthermore, the SpineJet XL appears to provide tangible benefits in terms of disk space preparation for graft placement, particularly when using the unilateral TLIF approach.

Ureter Injury as a Complication of Oblique Lumbar Interbody Fusion

BACKGROUND Oblique lumbar interbody fusion is a commonly used surgical method of achieving lumbar interbody fusion. There have been some reports about complications of oblique lumbar interbody fusion at the L2-L3 level. However, to our knowledge, there have been no reports about ureter injury during oblique lumbar interbody fusion. We report a case of ureter injury during oblique lumbar interbody fusion to share our experience. CASE DESCRIPTION A 78-year-old male patient presented with a history of lower back pain and neurogenic intermittent claudication. He was diagnosed with spinal stenosis at L2-L3, L4-L5 level and spondylolisthesis at L4-L5 level. Symptoms were not improved after several months of medical treatments. Then, oblique lumbar interbody fusion was performed at L2-L3, L4-L5 level. During the surgery, anesthesiologist noticed hematuria. A retrourethrogram was performed immediately by urologist, and ureter injury was found. Ureteroureterostomy and double-J catheter insertion were performed. The patient was discharged 2 weeks after surgery without urologic or neurologic complications. At 2 months after surgery, an intravenous pyelogram was performed, which showed an intact ureter. CONCLUSIONS Our study shows that a low threshold of suspicion of ureter injury and careful manipulation of retroperitoneal fat can be helpful to prevent ureter injury during oblique lumbar interbody fusion at the upper level.

Surgical Outcomes of Anterior Cervical Fusion Using Deminaralized Bone Matrix as Stand-Alone Graft Material: Single Arm, Pilot Study

Objective To investigate the safety and efficacy of demineralized bone matrix (DBM) as a bone graft substitute for anterior cervical discectomy and fusion (ACDF) surgery. Methods Twenty consecutive patients treated with ACDF using stand-alone polyestheretherketone (PEEK) cages (Zero-P) with DBM(CGDBM100) were prospectively evaluated with a minimum of 6 months of follow-up. Radiologic efficacy was evaluated with a 6-point scoring method for osseous fusion using plain radiograph and computed tomogrpahy scans. Clinical efficacy was evaluated using the visual analogue scale (VAS), Owestry disability index (ODI), and short-form health questionnaire-36. The safety of the bone graft substitute was assessed with vital sign monitoring and a survey measuring complications at each follow-up visit. Results There were significant improvements in VAS and ODI scores at a mean 6-month follow-up. Six months after surgery, solid fusion was achieved in all patients. Mean score on the 6-point scoring system was 5.1, and bony formation was found to score at least 4 points in all patients. There was no case with implant-related complications such as cage failure or migration, and no complications associated with the use of CGDBM100. Conclusion ACDF using CGDBM100 demonstrated good clinical and radiologic outcomes. The fusion rate was comparable with the published results of traditional ACDF. Therefore, the results of this study suggest that the use of a PEEK cage packed with DBM for ACDF is a safe and effective alternative to the gold standard of autologous iliac bone graft.